C O B B I N • A I R W A Y S

Airspace Files

2005-11-30T12:00:00.000-08:00

Worked out some glitches on getting the airspace files stored in the right directory / file for Flightgear to display the circular cores of B, C, and D class airspace. I'm only using an 8 sided cylinder for the circles at this point. Next, I'll work on routines to get the circular arcs and line segments in that make up the gerrymandering of the overal. airspace system.

The first shot is coming from Burlington, VT towards Lebanon, NH. Lebanon is 50 nautical miles off, and the blue band on the horizon is Lebanon's Class D airspace circle of 4.8 miles radius. The second shot is from the Manchester NH airport area toward Boston with Boston's inner and outer circular core of Class B airspace depicted. This is the classic upside down wedding cake airspace structure with a central core to the ground surrounded by an other shelf. There is a lot more complexity to the airspace system to put in, but this is a pretty interesting start. Generation of the airspace files is automated using the Defense Mapping Agency's DAFIFT data files to put together the airspace system into a flightgear compatable format. What a hoot!

As a low-time pilot, I always have a heck of a time pinpointing runways from far off and it sure will be nice to spot some by there airspace. Next, I want to see if I can modify the companion Atlas moving map software to display the airspace perimeter outlines, ala the way Klog does.

Class D Air

2005-11-26T12:00:00.000-08:00

So far I have managed to automate generating files for displaying the circlular core of airspace around class D airfields. Here is Lebanon in a reverse contrast image and the conventional summer terrain texturing native to Flightgear. My old 2nd seat in the legislator, also an A/P, Phil Weber, came by over the holidays from Pennsylvania.

I have also finally gotten around to doing a rewrite of my website to put some of the synthetic vision material on there, including the sources for the revised hud and code to interface with the Crossbow uNAV device. I also have been looking into getting a mini-ATX computer board to make the synthetic vision system portable so I can run some field tests... But, it turns out the graphic accelerator cards are power hungry and I haven't found an mini-ATZ with a power supply big enough to support the graphics card. If I had my choice, I would go with a Panasonic ruggedized laptop, the ones with the sunlight readable display, but at $3500 clams, that's a bit much.

Now, back to burrowing into the DAFIFT database. This is the same database, by the way, the defense mapping agency claims to want to take out of the public domain and make secret? I'm still curious as to what the hell the big secret is as to the boundaries of airspace already depicted on sectional maps! This sounds more like an effort to force people to get their data from some congressional chairman's pet defense contractor... For a fee. Come to think of it, one of those folks just got clipped in Kalifornia for being ye olde bribe bait.

Predatory Visit

2005-11-18T12:00:00.000-08:00

Have been working on automating decoding the defense mapping agency's DAFIFT database for airspace boundaries so I can display them in the synthetic image. Friday, two weeks ago, I was working away at the computer when up pops papa fox for a visit. As expected, he snooped his way around the corner to the (closed) chicken coop. Sorry pal, no chicken din-din today. This fella was pretty big, first time I've seen one with a white tipped tail.

Catching Up

2005-11-17T12:00:00.000-08:00

Couldn't resist trying out a crude adaptation of a logitech joystick to the control stick on the plane. Mickey mouse, but it works if you hold it down with one hand. Serously though, it was a nice excercise to see what kind of ergonomic nightmares/opportunites are associated with a keyboard in the cockpit. Definitely needs some tuning, but it turns out the logitech joystick controller probably is doable to track stick status at the cost of a usb port. The controller will interface to regular ports so the next step will be to machine up some bracketing to hold the resister and linkage to the stick.

Sunday Flying

2005-11-13T12:00:00.000-08:00

Sure got a tad hazy Sunday, but I wanted to get up anyway as I haven't flown since July 3rd. Was a bit rusty on the currency take offs and landings before taking Cathy and her mom up for some hazy sightseeing out towards Mt. Ascutney and Hawks' peak, the site of the 1947 B-29 wreck. The haze did not make for a perfect picture taking day. Here's a shot of the approach to 18 at Lebanon and a flightgear rendering of approximately the same position. Now, if I can scrounge up a laptop with an accelerated graphics board, I can get flightgear and the sensor running in an a portable unit.

For now, I'm still driving flight gear around to position the viewpoint and comparing them to photographs of the area. I'm pretty confident now that I can get the synthetic vision to work with Crossbow's certificied sensors in addition to their uNAV sensor... It is my understanding crossbow supplies the inertial device for the Chelton system. I also note that if other simulation software such as x-plane, or even (bannish the thought) microsoft publish an interface and support a documented socket programming protocol you could using sensors like the uNAV with a small programming translator to drive other simulation displays. A secondary issue arrises as to the pedigree of the terrain database(s) used by the flight sim, but that class of problem sure beats creating the display software from scratch!

From Canaan

2005-11-08T12:00:00.000-08:00

I finally got my sensor talking to Flightgear in real time via socket programming. If you're willing to thrash around for a while you can learn to do just about anything by studying source codes. It turned out I only had to tweak the uNav/Stargate published source codes a bit and run Flightgear on the TCP protocol (until I figure out how to shift to others? ...If it matters). First you make things work, then you make them elegant!

The output jitters a bit with about (1) degree of variation over time in heading position. I think this may be a calibration issue, but it will a while before I burrow into things and check that out. I may be getting effects from the fact that the sensor is in a cardboard box on top of the Linux box. Of course, for an extra $10,000 to $15,000 you can get a sensor that doesn't jitter... Anyhow, the uNav definitely is sensitive to iron as readily illustrated by moving a small screw driver near the device. I think I swung the compass (and the display depiction) about 15 to 20 degrees with the screwdriver. I wanted to take the picture of the device next to the monitor but nixed the idea because of the steel used in the support frame the monitor sits on. Plus I figured it probably wasn't a great ideat to get it anywhere near a flyback transformer...

Progress only cost me two lock-ups of my machine and I have some file system cleanup to do from the wreckage, but it is nice to verify that you can combine an inertial sensor with a flight simulation package and produce a sophisticated cockpit display capability.

Meanwhile, back at the ranch... Joel Godston (retired from Pratt & Whitney) gave a talk on jet engines this evening at our EAA chapter meeting. Joel brought parts! ...From his development days when they tested engines, and that occasionally meant frying them... When you think of it, the development of gas turbines over the last 50+ years has produced the most reliable and fuel efficient high output engines ever produced.

Synth Vision

2005-11-02T12:00:00.000-08:00

OK, so it takes a little spit chewing gum and bailing wire... But HOT DIGGITY DOG - It works! I have my uNAV sensor from Crossbow talking to my Linux box which runs the Kalman filtering algorithm stuff to output honest to goodness inertial data. I currently have the software writting a binary file in a Flightgear compatible format; then I feed the file into Flightgear to play it back and voila - the view from the house (which isn't all that interesting) so we artificially modified the altitude by adding 500 meters and presto... For your viewing enjoyment: The view from about 1500 feet above the house... And this is all with off the shelf technology!

Now, to get all this stuff working in a mobile package...

Back Home

2005-10-29T12:00:00.000-07:00

After finishing priming the fusalage this week, today was the big day to move the fusalage back into the house. Took a little wrestling. I've removed the sliding doors enough times now that I have that part of the procedure more or less down pat.

The trick we used this time was to drag it backwards up the slope to the opening and then place my small rivet cart under the rear spar bulkhead area of the fusalage. Then Cathy got the chore of weighing the tail down to lift the nose area so we could remove the gear and scoot it back into the room. Only hitch was we couldn't quite get enough lift to remove the main gear... So, a little mule lifting on my part under the fusalage and voila... We had the gear off.

Once it was back into the room we had to get a little extra lift again with the ol' thighs to get that little extra to insert the gear into their respective tubes. In any event, the fusalage is back in the house for the winter and sitting securely on a pair of steel saw horses.

Bush Plane

2005-10-28T12:00:00.000-07:00

One of the advantages of being newsletter editor is the opportunity to visit other chapter members' projects, like Dave Bridgham's shop where he is working a bush plane comparable to the Murphy line of bushplanes... Sort of an affordable version of a Beaver.

From the looks of the welded steel fusalage it will be as strong as an ox! Some of the features include use of spades rather than a conventional aerodynamic counter balance on the elevator to avoid the possibility of getting a jammed up elevator condition from twigs etc. in the rough terrain bush planes inhabit.

The floor tube structure of the fusalage is even trussed so this brute can handle some real loads... Dressed bull moose? Anyhow, Dave has a beutiful shop this looks to be a very interesting project to follow for the newsletter.

Flight Resources

2005-10-27T12:00:00.000-07:00

Had a chance to get together with our EAA Chapter's flight advisor Dino Vlahakis, pictured here with his beutiful Stearman. The irony, the photo is taken at Lebanon Airport (KLEB) in New Hampshire, and Dino is an international captain veteran with time logged flying into Bierut.... aka Bierut, Lebanon.

One of the things we are hoping to take advantage of is Lebanon Airport, because it has a tower, long, and wide, paved runways, and people like Dino in the chapter, who have been through the aircraft birthing process.

Meanwhile, back at the ranch: Put a the crosscoat of primer on the fusalage and when I was finished it was the end of my gallon of Dupont Corlar fleet grade primer. If things go well, we will have the bird back in it's nest for winter tomorrow afternoon or Sunday.

Making Power

2005-10-26T12:00:00.000-07:00

It took til about 2:30 this afternoon to get power... for 45 minutes then kaput! ...By then I had the fusalage taped off for priming, and I figured, "Phooey on the electric co-op, I'll just run the generator."

About midway through priming, it looked like the local area was back on the grid so I could turn off the generator. Man do those things make a lot of noise!... I'll double check the results Thursday to see if I need any touching up on the priming. Otherwise, I'll let it cure through the weekend and then it back into the nest for winter.

Storm System

2005-10-25T12:00:00.000-07:00

Cruising along alodining the fusalage, and I kept thinking, "Boy, the Wilma storm system is moving up the coast fast... Gee, that rain looks awful white." Got the fusalage alodined and then about 3:30 pm... ZAP! ...No power for like 23 hours ...Grr!

Oh well, nice opportunity to drink beer and play cards by the light of my ancient anchor light. Lately it seems like if two chipmunks get in a fist fight the power goes off! Come on boys, chainsaws are for clearing trees from around and about them power lines... Seriously, I'm begining to to think those power grid yahoos are just doing chicken and turning the power off. I'll be darned if I could find anything wrong with the power lines in Canaan.

Lake RV-7

2005-10-24T12:00:00.000-07:00

Fun upside down today scotchbriting the underside of the fusalage. Acid etched the skins. Tried using the sponge and bucket of water routine to clean the skins after etching. Finally threw in the towel... literally... and got the hose out to rinse everything off. Next stop, Alodine, Step B.

Heel Hook

2005-10-23T12:00:00.000-07:00

One thing I've always hated about working on cars is the issue of working upside down under the dash, etc. with your head held up. Makes for some interesting sore muscles the next morning! As a countebalance device, I found that hooking my foot over the saw horse seemed to eliminate the neck strain while running the drill motor to scotchbrite the fusalage bottom skins on the tail cone.

Hopefully I can finish the initial scotchbriting work on the fusalage tomorrow and then go on to acid etch and alodine the skins for priming. Then maybe we will have the fusalage primered and back home in the back room by November first. We'll see...

Prime Finish

2005-10-22T12:00:00.000-07:00

I started scotchbriting the fusalage friday, this should take a couple of days work through alodinining the skins. It took about a half day + to prime the other wing and after it cured somewhat I moved it to the house. I had to close off the back room as the solvent evaporation was getting a bit much, and I didn't think my mother in law would appreciate the cheap high her cockatiel was getting off the fumes...

I'll prime, if I can, the fusalage in the garage, sans the paint booth which I disassembled to make for some turn around space, so I could get the Elantra station wagon to pass inspection this year. Boy, with that paint booth out of there the garage is starting to look cavernous. Looks like a lot of rain coming our way, so I'll use the time to work on prepping the skins of the fusalage. If I can get the fusalage primed and back in the house before the snow flies hard we'll declare it a successful season.

Wing Prep

2005-10-21T12:00:00.000-07:00

Friday we managed to get the wing scotchbrited, acid etched, and alodined in preperation for priming. ...Ya know, the water off the hose is a tad cold this time of year!

Heading Home

2005-10-20T12:00:00.000-07:00

10-20a

Priming the wing takes a while! ...Like half a day. Starting to migrate the various pieces back into the house for winter. I have worked it out so I can put the wings, fusalage and empenage assembly parts all in the back room and still work on the fusalage innards. That, or the dining room is going to get stuck with the wings again!

But since pretty much all the fabrication and installation on the airframe proper is pretty much done, it's internal wiring and firewall forward on the fusalage. I am going to try to get the fusalage back in there and put it back on it's main gear so I can finish the gear leg details, like the brake lines, in the comfort of the house this winter.

Wing Saga

2005-10-19T12:00:00.000-07:00

Scoped out putting the wing tip on and decided against it for now, I'll do it during the winter in the house. Finished the platenut detailing for the wing root fairing, and acid etched and alodined the skins. In the evening, Cathy and I finished the grouting on the floor so we could start moving things back in for winter.

On the uNav front, I got the source codes for the stargate computer compiler on my Linux box and now I can run the uNav data through the serial port and have the software do the filtering to product the AHRS results, i.e. the pitch, roll and yaw angles, altitude, speed, latitude and longitude. Now to dig up a laptop, or it's going to look kind of funny with with my Samsung monitor in the back seat of the Oldsmobile for testing!

I figure to run the device in the station wagon I'll have to put it on a cardboard box to keep it away from all the iron! The magnetometers are sensitive, as demonstrated quite easily with a screwdriver placed a few inches from the device.

Hard Drive

2005-10-11T12:00:00.000-07:00

A simple little power failure, sometime after midnight, just after I had published my EAA Chapter's newsletter, and when the power came back on Linux would not boot and I got a nasty surprise to see the words "Kernel Panic!" as the last words on the monitor.

It took from the wee hours of last Thursday morning until about 3 o'clock yesterday afternoon to get the drive put back together and running again. For those who may run into this little disaster, here's a run down of what seems to have happened and how it got fixed:

Apparently from the power failure the superblock on the drive became corrupted, and accordingly Linux, would not mount it. But it gets a little more complicated. The system under Fedora Core 3 was set up with the Logical Volume Management (LVM2) disk management system. Under this approach the boot sector is on an Ext3 partition and the root "/" and swap partititions are logical volumes in a LVM2 partition. It took a while for that to sink in, particularly after repeated attempts run dumpe2fs to find the backup superblocks failed using the hardware mount points.

After I could not get a rescue disk to mount the drive I took a new 120gb drive and built a Fedora Core 3 system from scratch and dug out the source codes for the file system utilities. After some snooping around I started modifying a hack routine called "findsuper.c" to raw read the device and see what was on it. The boot partition looked fine, when I dumped some of the second partition to disk and looked it with a binary editor I got a nasty surprise when I went to where the superblock on an ext3 system should be. I found the text reference for the LVM partition. The real meanng of my fdisk checks on the disk now dawned me!

I didn't have very good tools for LVM under Core 3 so I bought the book on Core 4 and built a core 4 system from scratch on the 120gb drive. I got a little smarter (this is key!) when I built the core 4 system. I explicitly named the LVM components differently then the Core 4 defaults. This was necessary because if I didn't I never would get Core 4 to see the defective drive's LVM structure because it would have the same identifiers. With this construction I could then use the LVM gui to find the mount point which would now be under /dev/VolGroup00/LogVol00. I also installed Core 3 on a small, otherwise useless 5gb drive. With the little drive for testing I could now mount it's root partition at /dev/VolGroup00/LogVol00 and run dumpe2fs to get a report on the structure of the drive and where the backup superblocks where.

Armed with that info I started dumping sections of the drive to disk for snooping with the binary editor to make sure our understanding of how ext3 was structured jived with reality. Headway there, now it was time to try the bad drive.

Dumpe2fs would not work on the bad drive, but now debugfs would if you mounted it read only and with the catastrophic option (-c) turned on. I though, well, here goes nothing... Lets just run the "ls" command to see if we can read a directory... Voila!... or "Balok" in Lord of the Rings parlance ...We could read the drive root directory. That 5gb drive key to figuring out how to run debugfs and get it to mount the drive. From the little drive I could see that Linux sets the block size at 4096. And from that 5gb drive I got the backup superblock address. The boot sector block size is 1024, the root partition is 4096 and the difference is very important.

Anyhow, you have to run debugfs with both the blocksize and the backup superblock address specified. That done, I was able to start dumping directories onto the new Core 4 drive. After pulling off every key thing I could think of (including the 10+gb flightgear terrain, my nasa shuttle radar altimeter database etc.) I was now ready to take the plunge and run e2fsck on the sick drive to try to repair it. It took a couple of e2fsck runs with different settings and about 5 or six hours but finally, the drive passed systems tests with a clean bill of health and would boot. This email was generated from the system running with the fixed drive.

Gee, now that... That killed a week. I can hopefully go back to looking at the uNav, but first I've got to get some priming done before winter and there is still some firewood to rustle up... The fox picture is of a young one that keeps dropping by for a visit and taking a nap out in the open in the back yard.

Communications

2005-10-02T12:00:00.000-07:00

Solved my little communications protocol problem to talk and listen to the uNav sensor from a Linux box courtesy of some help from my ISP John Babiarz.

Crossbow doesn't provide datalogging source codes for the uNav so I'm taking the data log code for one of their other navigation sensors to write one from scratch. With that alligator skinned, I've still been pushing to get things primed before winter.

Finished fitting and drilling the wing root fairing. Also double checked the motion limits on the elevator and rudder per Van's specs. With that done, it was time to take the empenage apart and put everything back onto the storage cart. With the wing root fairing drilling completed we next took the temporary pins out and removed the wings. I'll next fit the wing tips to the wings and take the fuel tanks off to test them. If all goes well, I can then prime the wings, put them back on the storage cart, and prep and prime the fusalage.

I want to get the hardware processed before the weather runs out on me. I figure in the dark days of winter I can take my time working on the software/hardware to get the synthetic vision system up and running. I figure I'll test the system using the station wagon initially, then use a laptop to run some tests in a rented Cessna.

Priming Drill

2005-09-27T12:00:00.000-07:00

Acid etched the flaps and ailerons, then alodined, and finally primered them this evening.

Stop Position

2005-09-26T12:00:00.000-07:00

Yesterday I figured out a way of laying out the aileron stop position using a conveniently thick file. The aileron stop is a tiny little rascal so clamping it is a bit of a trick. With both drilled, I re-checked the travel limits and both sides are within Van's specs for limits. That done, it's onward and upward to start prepping the aileron and flaps for priming. Hopefully the weather will clear tomorrow and the temperature will rise so I can prep and prime the aileron and flaps.

Turkey Day

2005-09-25T12:00:00.000-07:00

The Turkeys keep making a visit to browse the field. It turns out the
large hens check out the place first then the rest of the flock shows up with this years youngsters to browse. Really neat to watch them.

Aileron Stops

2005-09-24T12:00:00.000-07:00

Priming of the empenage parts worked out pretty well. Found a fit problem with the fiberglass/rib on top of the rudder and formed up another rib and drilled and fitted it to make sure there is no interference with the rudder. Machined the stops for the ailerons and used my location jig (the angle pinned to the end wing rib) to drill the stops. Van's calls for the stops on the inboard aileron hinge bracket. I found the outboard hinge easier to set up on so I used that. I'll check with Van's to see if there is a big deal with doing that, but I doubt it. The ailerons are pretty stiff torsionally.

Paint Booth

2005-09-23T12:00:00.000-07:00

Tried out the new paint booth set up on the empenage assembly. The new primer was nice to work with. I went to a fancy cooking store to get a small assortment of dippers to mix the 5:1 ratio on the primer/activator for Dupont's OEM/Fleet grad Corlar primer. The sales lady was wondering what planet I dropped in from...

What's nice about the new primer was was you just mix it and shoot it. The industrial grade (a darker grey) has to be thinned somewhat to shoot. The wings and fusalage should be a bit of a wrestling match to primer... Stay tuned!

Turkey Trot

2005-09-22T12:00:00.000-07:00

Zipped out the front door and ...Nice surprise, the girls are in the front yard. By the time I went back in the house to get the camera the flock of turkeys were pretty well moved on.

Finally finished the paint booth and did another attempt at getting the crossbow sensor to interface with the software, this time with sucess. Looks like a bad or loose serial cable was the problem.

I really have to work at getting all the junk in front of the garage to the dump! Anyone need about 20 gallons of quenching oil? Also, you can figure it's a redneck household by the Christmas lights, which are still attached to the garage... Thank you!

Crossbow

2005-09-21T12:00:00.000-07:00

After a couple go-rounds via email with Crossbow I got the sensor running. Here, the shot is of the sensor powered up, but the software didn't recognize it, apparently because of a cabling problem.

Turned out the Crossbow check out software requires Windows 2000 or better and would not run on my 98 box. So, thanks to my ISP who had a Windows 2000 package in the shrink wrap... After swapping cables I got the sensor and the PC talking on Thursday the 22nd. Now to get Linux to interface with the sensor.

The secondary circuit with the large LED is the unit's power supply to guarantee a nice clean 4.98 volts to the device. Still hard to believe the little rascal has three accelerometers, three rate gyros, three magnetometers, a GPS, two pressure sensors, and a partridge in a...

The Sensor

2005-09-19T12:00:00.000-07:00

Finished welding the paint booth panels and started piecing... err... duct taping the panels together when the UPS guy showed up with the navigation sensor from Crossbow. Sure is a tiny little rascal. Hard to believe it has three accelerometers, three rate gyros, a GPS receiver and two pressure sensors on board!

Squaring Up

2005-09-17T12:00:00.000-07:00

The little details take a while to build the paint booth. Here we do a quick and dirty jig to weld the piece square...

Wingbathing

2005-09-16T12:00:00.000-07:00

Saw my aeromedical doc today to get a medical for the pilot's license. I see my Cardiologist Tuesday, and he'll be the key guy on info to the FAA for the medical. The treadmill test (a full nuclear imaging study) showed the schemia (low blood supply) downstream of the stent is still there... Course this all shows up when they have you zipping along at a rate I keep telling them I wouldn't do outside of direct medical supervision unless they were firing LIVE AMMUNITION at me! Other than that, no hiccups at the aeromedical... Wish me luck Tuesday with the Cardiologist.

Meanwhile, back at the ranch, we continued development on the paint booth with a modular plenum assembly to deliver filtered air to the booth. I figure I'll deliver air with a shop vac and duct the discharge downwind so I can keep overspray off parts in the garage. Of course there are alternatives, i.e. not that I haven't painted car parts outside, particularly when doing a quick and dirty rocker panel to get some old iron past inspection for another year. (Cathy's Geo Tracker has a particularly attractive set of rocker panels made from aluminum flashing complete with matching factory paint color sans the clear coat.)

Paint Booth

2005-09-15T12:00:00.000-07:00

To date I've been priming parts in the garage, and mostly interior surfaces. So if the odd bug or speck of dust got into the final result, I didn't worry about it. But now that we need to prime the exterior I thought I'd better take some precautions to protect the primed surface or face endless hours of sanding!

The mission has turned into one of how to make a portable paint booth without spending any money on it. I had a lot of 1/4 inch and 7/16 bar laying around the shop so I cooked up a modular 10' by 10' by 7' skeleton for a paint booth for starters. I figure I'll use plastic sheeting and duct tape to wall it all in...

EAA BBQ

2005-09-13T12:00:00.000-07:00

Tuesday I ScotchBrited the horizontal stabilizer and elevator parts then got to thinking it was time to bite the bullet on getting primer for the exterior of the aircraft.

Our EAA Chapter (740 Twin State Flyer's) met for the last BBQ of the season and we
had a pretty good turnout. I think I'm getting the hang of using the grill to flip the burgers.

Things were going just ducky until I went to the paint shop on Wednesday to get a gallon of primer... $350 poorer I went. I was not able to get the aircraft specific primer DuPont reps advocated at Oshkosh because DuPont does not sell it to jobbers, only direct mfg's like Cessna et al. So, after some discussion with the New England DuPont person we chose to go with the fleet version of the Corlar primer used in high end big rigs i.e. Autocar's.

I was previously using a heavier commercial version of Corlar and liked it, but thought I'd play it safe on the exterior primer to avoid any surprises from the unique thermal shock environment aircraft can exhibit relative to automotive and trucking applications.

Since we can't get aviation topcoat colors from DuPont I'm thinking maybe going with Ferrari Red isn't such a bad idea after all... But for now, we'll stick with just getting the bird primed for storage for winter. Onward and upward, we have more important things to work on than paint... But not just yet.

Stabilizer

2005-09-12T12:00:00.000-07:00

I liked how the horizontal stabilizer ribs came out so much I decided to make one for the vertical stabilizer as well. Not shown, but I actually made two of them, then took a little shortcut on the drilling (on the bench) and when found out it was crooked on the assembly. So... We cooked up a second one. These little custom
formed small ribs are really not that hard to make.

Rib Making

2005-09-11T12:00:00.000-07:00

The usual routine on RVs is to do some variation on fiberglassing the end pieces shut on the horizontal and vertical stabilizer sections. Now with some 2024 in fully annealled "0" temper around (from the canopy work out) and a piece of oak I got to thinking, gee maybe I should try to form a little rib to fill in the hole and just rivet the assembly shut.

Took a couple of practice pieces but, in the end it was worth it. Now all I have to do is rivet the rib to the fiberglass and pop rivet it to the empenage assembly. I did the first one before taking the hike to the B-29 crash site in Perkinsvill, VT this afternoon. When we got home we popped out the second rib and drilled and fitted them.

Now all I have to do is make another oak mandrel to form the the rib for the vertical stabilizer.

Dead B-29

2005-09-11T11:00:00.000-07:00

The Weathersfield Vermont Historical society hosted a "moderately strenuous" hike in Perkinsville VT today to the site of the 1947 crash a B-29 bomber on a training mission in rainy weather. Twelve souls were lost on what started out as a training flight from Tucson, AZ heading for Bedford Massachusetts.

Apparently the pilot had earlier tempted fate by dropping down and taking a peak and almost lost it according to one report where it almost hit the bridge in Bellows Falls. If he was dropping down to take a peak the second time, he got a very nasty surprise. He pulled and banked to avoid Hawks Mtn. (named after a 1700's militia general), but he didn't make it.

One hundred and seven people of all ages showed up for the hike. According to the Historical Society and the land owner, the parents, children, and grandchildren of those who died have made pilgramages to the site. It's very pretty, now, the accident at the time woke the whole town up and locals were on the seen in about an hour or so after making the tough hike with no trail in heavy rain to search for survivors.

It was a gorgeous day for the hike. By the way, the Historical Society published a reprint of some of the newspaper headlines from the time. My how time does not change. Among the headlines on "The Boston Herald": "Wallace Says U.S. 'Would Fight for Arab Oil'...

Fairings

2005-09-10T12:00:00.000-07:00

Took all day putzing around on the various platenut and hole drilling details to finish the gap fairings on the empenage assembly. Came out nice, and now to acid etch, alodine and prime everything.

Poking Around

2005-09-09T12:00:00.000-07:00

Small details day: After spending some time re-familiarizing myself with flightgears source code I finally took a break and finished up some details on the tail of the fusalage, namely drilling and tapping the 6-32 threaded holes for the horizontal stabilizer gap fairing attachment.

Chemistry

2005-09-08T12:00:00.000-07:00

After finishing up some details on the vertical stabilizer and rudder I tried out some Dupont treatments for aluminum to make sure the paint stays put when it gets on. First you acid etch the surface then you put on an alodine treatment to bond a sacrificial material to the surface as a last resort against corrosion. After treating and washing everything I was a little stuck for a place to dry the parts on. So the Oldsmobile rack got pressed into service.

More Feathers

2005-09-05T12:00:00.000-07:00

Turned my attention to the intersection fairing between the empennage assembly and the fusalage. I also started fitting the underneith metal fairing strip. I'll do as much as I can at this juncture before having to take the tail assembly apart to get at some drilling and platenut work for the fasteners to hold the fairings on the fusalage.

Once off the bird, the tail feathers will be primed before all the parts go back in house for winter. Should be a nice cavernous garage this winter for the winter sprawl of the plow truck et al... We were going to do some grouting today in the plane room but Cathy got a nasty case of tendonitis from working on the floor the day before. Slate floors last forever, but installing them can definitely leave you somewhat the worse for wear.

Tail Feathers

2005-09-04T12:00:00.000-07:00

Been doing some light detail work on the tail lately. Trimmed the empennage to fusalage piece, and will sand and drill it later. Finally got around to drilling the fiberlass pieces for the elevator and rudder. Have some more detail drilling on the bottom part of the rudder, and also need to form a little rib to close off the leading edge pieces.

We've been laying a slate floor in the room the fusalage sits in for the winter so I've only got these small items done while Cathy and I "recover" from laying the floor. Slate is pretty much indestructable once you finally get it installed.

Earlier in the week I finally ordered an intertial sensor from Crossbow in California. Thier uNav sensor. Their certificated sensor is something like $15,000 clams. Since this will be a VFR bird we are going to make the most of the uNave sensor which is actually designed for use in RC and UAV robotic aircraft... It's also only %10 percent the cost of it's certified big brother used I believe in the Chelton glass panel systems.

Chapter Items

2005-09-01T00:00:00.000-07:00

Message from C.G. Vlahakis:

Chapter patches are available at $5.00 each. See me at the next BBQ. We are planning to order golf shirts again. The last batch cost about $22/each. I will be getting a new catalog and will get current prices. Members can order colors and sizes and will be required to put $20 down before we will order. We do not want to be stuck with inventory and find that this is the best way. T shirts are available from Bill Molloy. See him at next BBQ or meeting.

Fiberglass Rudder

2005-08-26T00:00:00.000-07:00

Measured the fiberglass piece that fits to the bottom of the rudder for fitting. There are witness lines molded in the piece for trimming but I know better than to just assume they are correct, i.e. avoid the "cut once, cry often" problem.

Ditch Day

2005-08-25T00:00:00.000-07:00

Some days, when you can, there are better things to do than work on the airplane. Got out for a little climbing at whitehorse ledge at Conway NH with Shane Stewert and Mark Cave who are back from Iraq.

A Visitor

2005-08-23T00:00:00.000-07:00

Today we received a visit from my EAA chapter's newsletter editor regarding Frank Brunot's Rans project. Frank's getting started on the covering process for this fabric-covered plane, so he's pretty far along, and lucky dog, he's got an engine for it also. Really nice shop. I'm strarting the initial trim work on the fiberglass parts that attach to the tips of the tail feathers.

Bareplane

2005-08-22T00:00:00.000-07:00

Naked lady: We took the blue plastic wrap off to survey for nicks and scratches that need work before priming the surfaces. Finished some tweaking trimming on the flaps. Mainly surveying what details handle next. I may be able to order the crossbow sensor in a few more days so I can work this fall on some software development and testing for the flight display. Nice to have it at least look kinda sorta like an airplane, but the big ticket items are on the horizon.

Legal Beagle

2005-08-21T12:00:00.000-07:00

Legal beagling has kept me busy for a few days, but other than that I've had a chance to sit in as editor for my local EAA chapter's newsletter, on a meeting with our state's Executive Councilor Ray Burton to review Lebanon Airport issues (It's a little appreciated gem in the north country).

Dino Vlahakis (second from right with glasses in the 12 o'oclock is key member of our eaa chapter and, an EAA tech councilor, retired Pan Am pilot, and is currently on the local airport advisory committee. Phil Weber my seat mate in the legislature in the mid 90's and a A&P came by for a visit and look-see on how things are going.

After what my friend, retired navy chief George Shadowens, calls an SRC (S... Reduction Campaign) I was able to re-organize the garage so I could put the airframe together so I can work on fitting all the fiberglass and little details like setting the aileron and rudder stops etc. I'll probably strip all the blue plastic protective wrap and prime the parts before she goes back into the house in late fall.

Meanwhile, back at the ranch, we've orderd some slate so I can finish the back room before the fusalage goes back in there for winter.

Dolt Day

2005-08-11T12:00:00.000-07:00

Okay, it's official: DOLT for a day! Where's my beanie!? Cathy will be in the validation mode: "See if you'd stop to ask directions once in a while...." After horsing around with the camera to get a nice shot of our aged cat "Woody."

I finally figured out what I have been doing wrong with regard to getting programs downloaded and running on my microprocessor I bought to investigate the analog device rate gyro's, accelerometers, and those tricky honneywell magnetometer chips: It's a guy thing: READ THE DIRECTIONS CLOSELY, i.e. as my high school english teacher would yammer on... It's reading comprehension, stupid!

After leaving the book open to the right page for couple of days and actually reading it a few times while working on something else I thought gee... Maybe if I push the little button (a) and hold it and push the little button (b) once and with a little effort at coordination move the mouse over and press the reset button on the software... Presto!

Now I get to get lost in assembler. It's been years since I did any, never was good at it, and boy can you lock up computers mucho pronto... Good thing the magic incantations were not in one of the files the vendor shipped, which were still in the original Thai language.

EAA BBQ

2005-07-29T12:00:00.000-07:00

Had a great EAA chapter BBQ this Tuesday. Earlier in the day I checked and checked, and checked again my setup for the analog device microprocessor (just like a guy... hint) and NO WORKY! Very frustrating...

More Ideas

2005-07-27T12:00:00.000-07:00

Found some interesting metal working equipment ideas at Oshkosh this year. Like using a rivet gun mounted in a frame as an air hammer for forming parts. This would have made making the front skirt on the canopy bit easier to do.

I also finally got a good shot of the behind-the-panel view of Van's RV-7a demonstrator aircraft. Most of our intelligence work on aircraft details we committed to memory rather than take a ton of photographs. That way I could walk more and enhance the nasty blister I got on one of my toes!

Camping at Oshkosh was again very nice. It's had to believe you can be camping with 30,000 people and it's actually fairly quiet at night and everybody is very freindly.

Oshkosh 2005

2005-07-26T12:00:00.000-07:00

The seminars were a bit disappointing this year at Oshkosh. The NASA presentations in particular were bad. NASA two years earlier had some really interesting and useful technical presentions on synthetic vision, etc. This year, they were third rate.

On the bright side, the Crossbow folks showed up with a micro IMU intended for use on R/C and UAV aircraft. Still a bit pricey at $1500, the unit includes a GPS and pressure sensors for airspeed and altitude, but the ram air pressure sensor is ranged to top out at 80 m/s which is under the VNE for an RV... But I figured on using a Honeywell pressure sensor when I can afford it.

The firmware is supposed to be open sourced and there is a 400mhz motherboard available with Linux installed for doing the kaulfman filtering on the sensor inputs. I kept trying to trick the gyros at the display booth running just the sensor output fed serially to a laptop and it kept remembering where straight and level was, so my guess is they are doing some filtering on device itself which includes an atmell 128 microprocessor. Oh yeah, they include magnetometers on this puppy also... So in summary it's a 6 axis IMU with accelerometers and rate gyros, a GPS, pressure sensors and magnetometers.

I was happy as a clam to find out that the device uses the same chips I have been researching to use in building my own device. Last year the lowest priced Crossbow device was like 10 grand! The certificated rascals are still around 15 grand and Crossbow supplied the IMU for the Global Flyer.

Fire Valley

2005-07-22T12:00:00.000-07:00

Not content to cook in Death Valley, we thought we'd scope out what the story was on "Valley of Fire" north of Vegas and took my sister along for sightseeing and scorching...

Vegas Vacation

2005-07-20T12:00:00.000-07:00

Before going to Oshkosh we spent some time in and around Las Vegas. One day we managed to go from over 8000 feet to below sea level, which happened to be the day Death Valley hit 127 degrees. We set the camera to snap the one picture at the sand dune area near stovepipe wells. There actually were people who were going out to the sand dunes in this heat.

We drove a loop from Beatty Nevada to Stovepipe wells, then to Furnace Creek and then back to Death Valley Junction. The little jaunt required us to split a gallon of water and only cranked the windows down to enjoy the air for no more than 1/2 hour the whole circuit. I wouldn't want to have car trouble in that kind of heat, things can get serious pretty quickly. We were suprised how many people (fellow idiots) were at Death Valley... More than I usually see there in the winter time.

Beauty Shot

2005-07-14T12:00:00.000-07:00

Before going on vacation I couldn't resist putting the fusalage and tail feathers on for a picture in the driveway.

Winblows 98

2005-07-12T12:00:00.000-07:00

My last post included a screen shot showing some extensive backup copying of Windows 98 files on my Linux box. About the time I got the new USB device running under Windows 98 the old one hung up under Windows 98, and Windows claimed it now couldn't find a driver and proceeded to lock up the machine.

By the time the dust settled and after a number of reboot option attempts I booted the machine under Linux and analyzed the 98 drive and found Billy Gates and his whack operating system had eaten the Windows/system directory. So... Got to back up 99.999% of the files and 98 drive, then had to reformat it and reinstall from scratch.

Meanwhile, the postal service delivered my Analog Devices Micro Controller from Futurlec. This a Thai manufactured board and the brains of the little rascal is the surface mount chip on the board. It features 8 analog to digital channels (ADC's) which are 12 bit resolution. This is enought to get started with analyzing the rate gyro, accelerometer, and magnetometer signals. Eventually if things work out I'd like to get an instrument grade Analog Device model with 24 bit resolution.

The AHRS systems in use for radio control and UAV helicopter systems are using 8-bit ADC's. Honeywell regards 8-bit ADC's for their magnetometer chips as sufficient for only cardinal point representations of compass headings. The device costs as shown are about $60 bucks and about $100 dressed out with a meg of ram, eeprom chip and real time clock chip. In addition to orientaton sensor work I hope to evaluate the board for use in tracking flight surface position.

I'm wrestling with getting cars inspected (and fixed) before we leave on vacation early this year, including the annual pilgramage to Oshkosh. This year we'll concentrate on wiring, avionics, fiberglass, and painting seminars.

Device Drivers

2005-07-09T12:00:00.000-07:00

Worked out the initial setup for the hardware (or so I thought) to read the serial port under Linux. Finally broke down and got the volt meter out to check for tranmission activity and discovered (a) the transmit/receive lines were backwards and (b) a 3.3 volt supply voltage was wrong, you need a ttl voltage in the 5 volt range. The voltage issue was sort of obvious in hindsight, but than again hindsight is always equal to or better than 20/20!

Still could not read the device under Linux and downloaded Windows drivers for the new USB device to verify it was working. Finally have gotten to the state the new device will read under Windows. There seems to be a problem with the Linux driver: I can open the device as a virtual serial com port and when I go to read it I can see from the volt meter the little rascal starts transmitting away... But my Linux code gets stuck on the read call which does not return. This sounds like a driver issue, so we are going to have to sink a little deeper and burrow into the driver source codes and see if we can do some debug routines in there find out what the hang up is.

We're getting there, but it is a tad frustrating to get stuck on I/O issues to get the data off the hardware.

Ferrari Red

2005-07-06T12:00:00.000-07:00

Late spring cleaning: Throw the plane out of the house!

Came up with a simple wheeled arrangement to wheel the fusalage out of the house after taking the sliding door apart. Boy, once the mains and the nose wheel are on with the tires it sure stands up there a tad, making me wonder about that decision not to build in the optional step kit!

I figure with some fiberglass work to do I'd rather have that dust out in the garage than in the house. I used to machine fiberglass at Tech Systems in Thomaston CT years ago and I still itch just thinking about it. I'm thinking of taking all the blue plastic off and doing a coat of grey epoxy primer on the fusalage.

Now if I can just figure out how to get 180-200 hp powerplant, prop, wiring and lights... Boy it sure does look bigger than it did in the back room! I may later in the week plug the wings and the rest of the flight surfaces in just to oogle it a bit. We're kicking aroun the idea of painting it Ferrari Red.

Buck & Roll

2005-07-05T12:00:00.000-07:00

Made a simple little modification to one of my bucking bars so I could add a little 2 inch length of tool steel to make a foot. With this bucking bar hand I was able set the last 4/5 rivets on the forward canopy skirts. Figured while I was at it, it was time to finish the last few rivets on the roll bar assembly. I would say the airframe is complete at this point... But for a couple of rivets on the firewall to lock the firewall recess in place.

Rock Face

2005-07-04T12:00:00.000-07:00

Okay there's more to life than working on the airframe:

My climbing partner from law school, Shane Stewart, is back from Iraq and wanted to go climbing. Nice day on Whitehorse Ledges at Conway, NH and we were able to climb through the crowd. This section is pretty easy friction climbing although people new to the sport can use the crack in the arch to plug in some protection. Just out of sight in the picture to the right of Shane here in the lead is a small army camped out the belay: an Eastern Mountain Sports guided party with a zillion ropes.

At 51, with two heart attacks under my belt, it's a real treat to still be able to do these duffer routes, but I sure pace myself. I was also more than happy to let the young whipper snapper do all the leading, particularly as one of the pitch up over the granite bands above requires some overhead work and I try to keep the arm power work in limits as both heart attacks got kicked off with over doing it in the upper body department.

We wound up passing all the college kids, as it turned out. We are both pretty efficient at the gear change over at belay stations. Hopefully next time we'll bring some more carabiners as I was scrounging all day. I took and drank a liter of water on the route. The days of going all day on little or no water are now long gone.

In The Air

2005-07-03T12:00:00.000-07:00

Finally got some decent flying weather! We were planning on going out on the second for my birthday but it was just too windy and I'm still a low time pilot planning on living to be a high time pilot.

Haven't flown for a little over six months so after doing some touch and goes to get current we just did a little snooping over the homestead. The house is 3/4 the way up the frame and 3/8 over from the left edge. Sure was nice to be able to impress Cathy with a nice smooth greaser of a landing on the return to Lebanon.

Circuit Work

2005-07-01T12:00:00.000-07:00

Put together a 3.3 and 5.0v power supply for use in testing the rate gyro and accelerometer. Also received a USB device for use in circuit development. I'm a little chicken yet to try to patch it into the circuit board that the GPS attaches to in light of my little boo-boo with the magnetometer the other day. For now I'm still studying the circuitry.

Test Rig

2005-06-29T12:00:00.000-07:00

Made up a test rig to evaluate the Z-axis magnetometer from Honneywell. I got three sets of 3-axis magnetometer chips for building a tilt compensated compass. The chips are all micro tiny surface mount chips with the largest one being the Z-axis magnetometer.

I have to fabricate a circuit board to mount the other chips just to test them so they are going to sit for awhile. The magnetometer signal is a small (millivolt) range signal indicating the magnetic field.

Finally started to get the hang out of mapping the signal when I had a slight misunderstanding of the proper method to cycle the reset pin... Over amp'd it and zap - Adios! Lesson learned the hard way. Good thing Honneywell sells those chips on a minimum order quantity of 3.

Accelerometer

2005-06-27T12:00:00.000-07:00

Worked up a quick test rig to get a feel for what the accelerometer signal looks like on a little road test with the Elantra stationwagon. The voltmeter shows about the midpoint of the supply voltage. The Analog Devices two axis unit modifies the voltage on the pin to reflect the applied acceleration for ± 5g's.

This type of sensor appears to be originally developed for tilt compensation of digital compasses, but people have gone on to use them along with rate gyros for attitude/heading reference systems for remote control/UAV helicopters.

Test Fit

2005-06-26T12:00:00.000-07:00

Cathy wasn't available when it came time to take the canopy off, so I came up with a simple solution to hold the nuts on the inside under the front of the windscreen while I removed the screws. It really is nice to be able to take the plexiglass back off the plane. This should be a real advantage when it comes time to paint everything.

Black Hole

2005-06-22T12:00:00.000-07:00

Pretty darn small. This is the GPS unit I got from SparkFun electronics. I'm not knocking them but the Silicon Lab's outfit out of Austin Texas that makes that little tiny black chip... Grr! Seems as though they are committed to playing hide the ball on device drivers.

I finally verified the device was working with a GPS diagnostic tool downloaded from the GPS unit manufacturer running binary drivers for Windows (rebooted to a legacy Windows 98 box for this type of problem). So, we know the chips and the board are working, but getting the communications to work accross the last 1/4 inch from the USB connector to the GPS unit in the silver box... A proverbial black hole.

Silicon Labs has releases source code for a Linux driver for 2.4 kernals (I'm running a 2.6 kernal) but some BOZO thought he would be cute by chopping the source file into single token bits and be a real wise guy and convert all the identifiers to variations of "O0100101010101" type strings make the file gibberish. I wouldn't care if it compiled but it don't...

On the bright side, I've been able to use some tools to interrogate the little rascal to get it to identify it's USB-2 parameters. Now if I can get the bulkread function to work, I may be able to get the GPS unit's output stream. Still, it's a cute little rascal. Kind-of funny how the antenna is bigger than the actual unit, and the power for the whole shebang comes off the USB cable.

Oh well, at least I now know the front steps of the house are more or less located at 72.06864 degrees West and 43.71213 degrees North at an elevation about 335 meters above mean sea level.

GPS Time

2005-06-21T12:00:00.000-07:00

Put some finishing touches on the canopy plexiglass to countersink the holes and draw-knife the edges to get rid of any stress-riser scratches. I tested out installing the canopy with Cathy and we got screws and nuts finger tight in practically all the holes.

Got a call from the post office about 4pm to see if I wanted to pick up an express package that had come in late, which turned out to be the GPS/USB board combo I ordered from Sparkfun Electronincs. Cute little unit, but it turns out the USB chip maker has been playing games on releasing driver information... A very bad start.

Looks like we are in for a little "fall in the ol' black hole" session chasing communication protocols. Looks like I am about to get immersed in the trials and tribulations of Linux USB interfacing (LIBUSB). After burning through the afternoon and all evening I was able to verify the kernal sees the device and knows who it is.

Now I need to figure out how to get the bulk transfer protocol to work and burrow through the GPS chip's documentation. This ought to kill a solid two weeks... Honeywell sent me an e-mail saying they shipped the chipset for the digital compass.

Canopy Day

2005-06-20T12:00:00.000-07:00

Finally, after months of various details it was time to rivet the canopy frame. It turned out the key to riveting the skirts and skin in place (with the underlying stiffeners) was to rivet the skin/stiffeners on the outboard edges first, then rivet the skirt on and then rivet the center stiffener in place.

To make this sequence work I machined up a modified version of the bucking bar I worked out helping Brian on his 7A. What I needed was a larger "foot" to fit under the stiffener to buck the rivets on the outboard sides of the skin. When the dust settled I was still four rivets short of having them all installed. (I need to make a bar from scratch with a longer "foot" to buck the last four rivets.)

Van's aircraft should really consider providing a little more information on the option of making a metal skirt instead of the fiberglass layup method of attaching the front of the canopy. It really isn't all that hard (just tedious) to make those front skirts using essentially just a stick of oak with a slot cut it in. It may be the old fashioned way of hand forming aluminum parts, but it works!

When I worked at Connor Engineering in Danbury, CT in the 70's there was an old timer in the prototype shop who would tell stories of his early days making aircraft parts for Chance Vought et al. When he started out, he was shown a bucket of mallets, a sand bag, and a sheet of aluminum with the announcement: Sonny I'm going to show you how to make an engine cowling... May be slow but hand forming parts still works.

If you look at the air inlets on the leading edge of EAA's Aluminum Overcast B17 you can see they are hand formed. In any event, I sure had fun working out how to make those skirts and I would recomend anyone building an RV at least consider the alternative to the fibeglass layup method. Think of it as a stress reducer - or producer - depending on your disposition.

Thanks to Dino for getting me the invite to Plymouth Airport to crash their BBQ so I could talk the builder of the RV-9 which had aluminum front canopy skirts. It was a real boost to talk to someone who had actually done it and get some insights into how it should be done.

Bright Light

2005-06-19T12:00:00.000-07:00

Finally some sunshine! Took advantage of it by priming some canopy parts for final assembly.

Sequential

2005-06-18T12:00:00.000-07:00

Finally worked out the sequence for riveting the final assembly (I hope) and it's kind-of tricky as I am trying to flush rivet the forward canopy skirts and the riveting of the braces inside the assembly makes for a sort of dock and dinghy problem...

More Plans

2005-06-17T12:00:00.000-07:00

Prepping parts and planning out the riveting for the canopy...

Final Drill

2005-06-16T12:00:00.000-07:00

Finished drilling the front skirts to the canopy frame. It took a little bit to work out the details to zig-zag around some structures. Came up with a simple gauge to check for clearance for a screw to secure the canopy to the front skirt. Once the hole locations were worked out it was time to take everything back apart to drill pilot holes in the skirts, then put it all back together to drill the pilot holes through the canopy.

Now it's time to take it all apart once again for the final drilling to size and countersinking on the canopy etc. and then we'll be ready for final assembly of the parts. Kind of neat to be able to bolt the canopy on and then be able to take it back apart again, hopefully this will pay dividends when it comes time to paint the plane.

Some Issues

2005-06-15T12:00:00.000-07:00

With the skirts formed and fitted it's time to lay out the holes and drill them. This is still a work in progress, in stages, as there are some issues with a couple areas regarding to how to interface with some of the other structures that make up the canopy frame. This is going to be a riveter's nightmare on final assembly, as we try to avoid having to use blind rivets.

Form Fitting

2005-06-14T12:00:00.000-07:00

A couple of days back the 2024-0 sheet arrived. So today it was time to form, then drill the skirts into place... Here's a three photo synopsis of the sequence of forming and fitting the skirts.

You basically set the flange with the notched oak stick, wipe the bend to fit the cross section with your fist "ironing" the sheet over the bend in the fusalage. The ironing takes some of the flange angle out, but not all of it. So you trial fit the piece, then do a little more with the oak stick, iron the piece etc. until you get the fit right. After that I trimmed the left and right ends to butt up against the canopy frame sheet metal.

Stainless

2005-06-12T12:00:00.000-07:00

Saturday and Sunday finished up some miscellaneous firewall details like making the hole big enough through the firewall so you get the bolt into the engine mount weldment which holds the front gear leg on. Deburring stainless takes a real effort.

Monsoons

2005-06-10T12:00:00.000-07:00

Canaan has been getting hammered by thunderstorms the last couple days. Closed route 118 with a washout. We've been pestering the town for a couple years to fix the culvert and thank goodness they finally put in a new 2 footer to replace the ancient (collapsed) stone culvert.

Meanwhile, we're finishing firewall and canopy details. The side skirts and canopy latch fingers are ready for priming. If my GPS unit gets here I'll see if I can run some software tests: Of course, without a laptop it's going to look pretty funny to lug the workstation out to the station wagon. If I can mooch an oscilliascope somewhere I'll also take a whack at testing my analog devices gyro.

The Dallas Texas based robotics group's website at http://www.dprg.org has an interesting page on circuit board for use in a two wheeled standing robot and links to expresspcb an internet based prototype board fab shop. Was looking at patent number 6,671,648 on the USPTO's website on gyros which gives an interesting background on just how many types of gyro's there are. I might put a little summary doc together after I do a little more background vacuuming of sources.

Skirt Flash

2005-06-08T12:00:00.000-07:00

Pumped up with the knowledge it can be done, courtesy of the RV-9 yesterday, I proceeded to work out the kinks (literally) in forming a front skirt molding for the canopy using aluminum roofing flashing as a test media. I figure flashing has to be at least strain hardened to a half hard state to begin with, as the stuff doesn't form worth beans. Still with a lot of patience you can do it... It came out so well I went ahead and ordered some -O temper annealed aluminum sheet from airparts to take a crack at the real thing.

Bullwinkle BBQ

2005-06-07T12:00:00.000-07:00

Finished mounting the main tires to the rims and assembling everything onto the main gear legs this afternoon, but not before an interesting and productive diversion. Dino Vlahakis called to let me know of a BBQ for retired airline pilots at Plymouth airport and suggested I come over to look at some of the RV's.

I finally got a chance to see the RV-9 I spotted back in May without the canopy covered so I could check out the interesting approach the builder, Malcomb Brawm of Hebron NH, used to secure the windscreen. Normally, the front edge of the canopy on RVs are fiberglassed to the fusalage. This RV-9 uses a sheet metal skirt to do the same thing, only with this method you can remove the canopy (for painting).

Malcomb was very helpful in sharing how he fabricated the windscreen skirt. The shot of the Stearman is Dino's plane on departure from Plymouth. I couldn't see worth beans on the digital camera display because of the glare and took the shot anyway. The young moose are moving around now and it was a real treat on the drive home to get the shot of the young bull moose, but unfortunately I don't think he'll fit on the tail as a mascot.

Rolling Along

2005-06-06T12:00:00.000-07:00

Finished the last pop rivet details on the center harness anchor this morning. Here's a shot of the the cockpit with all the sheet metal (etc.) in place.

Shortly after taking the shot I also put in the vents and piping. I've been itching to move on to get the wheels done to be able to kick the fusalage out of the house for the summer. The nose wheel and its assembly worked out pretty straight forward but... And there's always a but... The main gear stumped me.

There are a couple of fastener details to the main gear's tubes on the nozzle I need to figure out before I can for sure split the rims, insert the tube, and inflate the tires. The plans for the disk brakes on the mains are a tad sketchy also, so it's going to take a bit to get the order of assembly down pat.

On the avionics front I ordered a GPS unit that I can read through a USB port the other day, and may have a source for an experimental six axis attitude sensor system. The GPS unit is sold by the same outfit that pretty much tracks all the big rigs you see on the highway these days.

Harnessing

2005-06-05T12:00:00.000-07:00

Used my new pop rivet gun to start installing the center seat belt attachment point. I kept removing a little metal here and there on my old pop rivet gun then ...Argh! Dropped it and disintegrated the nose piece.

Side Skirting

2005-06-03T12:00:00.000-07:00

NC drilled the rivet hole pattern in the side skirts and fitted them to the canopy frame. CNC drilling the hole patterns looks a whole lot better then my battling with a wandering drill point with a hand laid pattern.

I found particularly with drilling that cleco's that the occasional extra clamp is all that's needed to hold the sheet metal against a piece of wood. What I did here was drill a series of 10 holes, then I moved the piece on the jig and reran the program to extend the pattern... Do that a couple times and you have nice, evenly spaced holes.

Canopy Skirt

2005-06-02T12:00:00.000-07:00

If I were a master at metal forming arts, I would make the front canopy skirt in one piece. Since I'm not, I'm going for the two-piece approach using a pair of "flat" patterns to develop the skirt.

The upper pattern is for the piece to wrap around the canopy, and the second is for the tie-down piece which wraps accross the canopy frame skin. The upper pattern requires a blank about 54 inches in width and the lower one requires about 48 inches.

Eveningwear

2005-06-01T12:00:00.000-07:00

Doing some work on pattern development. I've been playing around with aluminum flashing to work out fabrication and fastening options. This is going to kill a lot of surface area of some aluminum sheet(s) eventually so I'd really like to get this right the first time.

The idea is to wrap the upper piece accross the plexiglass and with the tabs bent up to intersect the canopy frame's skin... Then put a cap over the combination to rivet the assembly to the canopy frame/skin and then bolt the canopy to the skirt. Cathy says this is like the pattern work to make a shirt collar.

Plexi Finish

2005-05-31T12:00:00.000-07:00

I've tried sanding edges but I have finally settled on the draw knife method to remove nicks and grinding marks. The trick is to ALWAYS use a negative rake angle... You want to take marks out of the edge not put them in. The Bowie here was homegrown from a leaf spring.

Long Reach

2005-05-30T12:00:00.000-07:00

Finishing up some of the miscellaneous details laying around for the cockpit. This shot shows off the L-O-N-G-reach yoke we picked up last summer at Oshkosh to finish some of those hard to reach spots.

Gator Time

2005-05-29T12:00:00.000-07:00

Boy, that alligator squezer we bought at Oshkosh two years ago sure comes in handy sometimes. You have to rivet the skin on first (i.e. the day before) before you can set some of the bulkhead rivets or you will find yourself in a riveter's trap. With the skin on, it was time to go back inside the tunnel and get the last couple of 1/8 rivets that had to be set.

Skin Wrap

2005-05-28T12:00:00.000-07:00

The skin that wraps around the rear window has always impressed me as begging for a hanger rash accident in the making. So we were quite pleased to finally get to rivet it on. Boy is it cramped in there, but not as bad as I thought. I made up a plywood panel to lay on, and Cathy ran the gun and did the bucking bar chores.

Last Prep

2005-05-27T12:00:00.000-07:00

Deburred dimpled and primed the rest of my small parts and the parts for the canopy. This is probably the last time I will need the big c-frame press to dimple the sheet metal for riveting.

Patterns

2005-05-26T12:00:00.000-07:00

Working on build-up of a set of patterns to comprise a metal fairing for the front to the canopy bubble. This will be a two piece affair. I'll try anything at least once to minimize my exposure to working with fiberglass... I used to machine the stuff years ago, and I still remember itching!

Experiment

2005-05-25T12:00:00.000-07:00

Besides drilling some more harness brackets in place using the right angle attachment on my dremel tool, I cooked up a little test jig to see how accurate logitech joystick controllers are. My micro steppers for the mill divide 360 degrees into 2000 steps... So, since I do not have an indexing head I hooked a 150Kohm pot to the saddle's stepper motor and moved my regular computer out the garage read the joystick output data.

The joystick reports motion scaled on the interval from 0 to 1 with one axis being -1 to 1. My readings showed the controller outputting on the 0 to 1 interval with 0.01 being the minimum increment. Now the bad news: With an external resister alligator clipped to the circuit the noise is in the range of 0.03 and seems to drift up and down over time making my suspicios of (a) noisy device and (b) something funny going on in the chip's a/d sampling. The tiny pots native to the controller seem to work on 0.01 increments by and large without the noise.

Even with the noise, the accuracy is probably more than sufficient for use tracking actual control surface positioning such as the flap.

Belt Harness

2005-05-24T12:00:00.000-07:00

After some epic battles with the cars, I was able to start on fitting the extra seat belt harness location between the legs. Something tells me this job would have been easier before putting the fusalage skins on.

I had lots of fun with the Elantra... Seems as though its clutch works backassward of the usual fork press on the throughout bearing which presses on the pressure plate. Oh no, those sneaky Korean engineers had to come up with a clutch where you pull on the pressure plate with the fork/throwout bearing! Which means you can pull like all heck and nothing comes apart until you do the magic trick of removing the slave cylinder actuator arm so the fork can over-travel and disengage said transaxle from said engine.

Light Duty

2005-05-19T12:00:00.000-07:00

Last Thursday was the last day I worked on the plane. I'm slowly working off the odd rivet here and there, and have a tray of parts to do the final prepping on for priming and installation. I'm planning on making a pattern from the top skin of the canopy frame to see if I can make a metal fairing for the front of the canopy instead of the usual fiberglass lay-up.

It's firewood season now that the logger finished taking some pines off the property. I skidded some logs up to the front of the house for chain sawing into fire wood. It's definitely black fly season, too! I've been stuck under the Elantra for the last couple of days putting a new clutch in... Man do I hate the smell of Hypoid gear oil!

Bucker's Eye

2005-05-17T12:00:00.000-07:00

Tuesday night we finished the riveting on the F-771 forward top skin. It isn't as cramped under the hood as I had feared but it isn't a cushy sofia neither.

Upsy Daisy

2005-05-16T12:00:00.000-07:00

We got most of the forward top skin riveted tonight. The firewall was the trivial part with the aligator squeezer. The rest of it was fun with Phil on his back on top of the main bulkhead for the wing mainspar with my legs draped over the side, my head under the skin and one arm curled over the other side to get some leverage to hold the bucking bar under the skin while Cathy ran the rivet gun from above.

Wasn't really as much of a Harry Houdini session as I had feared, but we called it a night and we'll finish the outboard rivets on the left side tomorrow... Assuming my neck doesn't turn to rubber tomorrow...

The photo a few days ago showing a pile of wiring and circuit boards was the innards of a Logitech Extreme 3D-Pro joystick. I'm looking into the feasability of using it to track the position of the elevator, rudder, aileron, and flaps, plus stick hat switches.

I also picked up a breadboard at Radio Shack so I can start running some tests on the analog device's rate sensor I picked up a while back.

Bucking Bar

2005-05-15T12:00:00.000-07:00

Machined a simple bucking bar to get under the main longeron and set the rivets. Other than this bar I only needed some simple 1/4 inch thick steel bars to get at a couple of the more cramped space locations.

At this juncture we are doing finishing details to get ready to rivet the top skin on. I have decided I want the top skin buttoned up before finishing the canopy as I found (with the gas struts) the canopy position can be move slightly when just the clecoes are used.

Riveting Details

2005-05-14T12:00:00.000-07:00

Decided it's finally time to rivet some of the parts for the on the fuselage before going any further on the canopy. Riveting the to top rail pieces turned out to be easy, but I'll need to make a bucking bar to set the rivets that go through the main longeron. Started fitting the air vents to the fusalage, and I'll seal those in place and rivet them.

Gas Struts

2005-05-12T12:00:00.000-07:00

Finally finished the small parts to mount the gas struts to hold the canopy open. Took about two days of fiddling to machine all the parts and a drill jig to set the position of the front mounts. A funny thing happened after I drilled everything and installed the struts: The gap between the canopy and rear window opened up! Those struts do a lot of prying on a clecoed assembly and even more when you do not have the front top skin clecoed on.

Upshod: You do not want those gas struts anywhere near the fusalage while you are fitting up the skirts, etc. - Until everything is riveted finally into place. Of course, the final riveting of all the fuselage/canopy parts is starting to look like the proverbial chicken and egg problem... Who goes first and after that what order?

Field Trip

2005-05-11T12:00:00.000-07:00

Dino Vlahakis, our EAA chapter's flight advisor, came by for a visit and we went over to the grass runway at Plymouth, NH to visit Bill Grady, a retired airline pilot, and his RV-7 which is nearing completion.

Bill had previously built a very nice RV-6 back in the days when you had to lay out and then drill all the holes. I won't bore everyone with samples of my 40-odd intel shots of Bill's RV-7 or the brand spanking new (as of May 1, 2005) RV-9 parked on the grass awaiting inspection to get an airworthiness certificate by Mr. Malcomb Brawm of Hebron, NH.

Those RV's just keep popping up, what a great airplne kit!

Small Parts

2005-05-10T12:00:00.000-07:00

Back making small parts for the lift struts for the canopy. Had an interesting EAA Chapter meeting this evening with a presentation from an engineer who worked on the Garmin glass cockpit display's attitude reference system.

Speaking of attitude reference systems: a little while back I received the following info on a new system developed in Europe:

We are pleased to inform you about the release of the MTi, the world's smallest Attitude and Heading Reference System. The MTi is the successor of Xsens' MT9 Inertial Measurement Unit and its main improvement is the internal computation and direct output of the Pitch, Roll and Heading angles with 0.5 degree accuracy.

The MTi will be released at the Sensor + Test tradeshow, to be held from May 10-12 in Nurnberg, Germany. Together with the MTi, we introduce the even smaller MTx 3DOF Orientation Tracker for human motion measurement. Please, visit http://www.xsens.com/mti_ahrs.htm or contact me for more info about the MTi.

Try Again

2005-05-09T12:00:00.000-07:00

The ejector rods for pulling the pins on the canopy hinge were both machine 1/2 too short... Speedy blueprint reading on my part... So I ordered some new steel tubing from aircraft spruce and got to make a second set.

Nice View

2005-05-08T12:00:00.000-07:00

Finished the basic countersinking and hole prepping for the rear window and then the initial trimming to get about a 1/32 inch gap between the canopy and the rear window. Cathy got first dibs on sitting in it with the canopy on. It sure gets warm under that canopy. Time to start working on the gas strut mounts to hole the canopy open.

Rear Window

2005-05-07T12:00:00.000-07:00

Finished the initial drilling of the back window and the countersinking and dimpling of the rear edge. The procedure I have been using is to set one countersink cage to the countersink depth for the screw and sheetmetal, and one for chamfering the inside edge slightly to remove the stress riser. At this point, what's left is the countersinking on the roll bar, the trimming for the line between the canopy and the rear window, and the internal aluminum strips to finish securing the rear window.