<Chapter Eight cont. cont.
After much sanding, grunting, and sweating, we got the belly into a reasonable state and decided that the old girl could get off her back . We turned her over, put it back into the cradles and sat back to admire our handiwork. Picture below shows an elegant leg.
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After the all too long admiration bout, we started looking at the next steps and decided to tackle the horizontal stabilizer (HS).
First, the fuselage was set into a correct orientation with the center of the earth, again use was made of the hi-tech water level. The stabilizer was then set to the correct orientation with respect to the firewall and the center of the earth. There are several (4) degrees of freedom so a whole bunch of measuring, tweaking, re-measuring, and re-tweaking went on. We marked the parts and then prepared the surfaces. Applied Hysol in copious quantities, reattached the HS, one round of measure-tweak and a weight applied to the center of the HS, a stabilizing 1x2 screwed to the workbench and the HS and we let the little molecules do their work. Photos show the crew, Bruce DeChasel (Henry’s friend from Australia) Henry, me, and Nathan in the "measure-tweak cycle" and the second shows the stab in place while the Hysol "cooks."
Next I decided to tackle the back seat and associated parts. I quickly ran out of prepreg. I’m convinced that I never received all the prepreg I should have. Vern very kindly sent out a sheet which should take me close to where I need be. The back seats, elevator control tube tunnel, spar cover and front seat web cover are all in place and look pretty good. This whole assembly proved quite straight forward and easy. The picture below shows a view looking forward and the elevator tube cover and back seats can easily be seen.
Now onto completing the tail feathers. Followed the manual in mounting the vertical stabilizer. Attached the right half first, bonded in the air scoop for cabin air. I’m toying with the idea of correcting the NACA duct assembly. There is no fairing on the inside of the scoop as the information on NACA duct says there ought to be. I think a piece of foam covered with a 1 or 2 bid should do it. But that’ll come later. The right side went on quite easily after I bonded in the stern post. The ribs and spars went in next and were completed by attaching their caps. We futzed around for a while with the flange for the ventilation SCAT tube and landed up with the world’s strongest flange. Then attached the left side skin. We clamped straight edges to the trailing edge of the skin to ensure it set straight. Came up with a simple idea of ensuring the skin is intimate with the rib and spar caps. A couple of strategically placed deck screws snugged things down quite nicely. When all was done, not too close inspection showed that I too have the twisted tail. We’re going to fly it and then fix it if needed. First pic shows how handsome the empanage is starting to look and the second the innards of the Vstab, note the com1 antenna at the leading edge.
Now started stringing wires through the fuselage. There is a LOT of wire in this thing. Constructed a panel to which the avionics mount. The KG 102 remote gyro, 12 to 24 Volt converter and the WX 500 Stormscope processor live here.
This naturally progressed to the panel. The first phase was to determine what goes into it. A lot of soul searching and thought went into deciding as to whether this was going to be all electric or not. The pro’s were… one electric system dies, the second takes over all the stuff that makes it easy to aviat, navigate and communicate (as my first flight instructor used to chant). The minus to me was that in all the designs I’d seen there was always a single point of failure that would render the entire system inoperative--a bad thing in the murk. Also in my 1400 hours, I’ve had five electrical failures (three were busted belts), one failure was in IMC. And zero vacuum failures--did have an artificial horizon die though. So I went with the hybrid-system (vacuum and electric) we’ve come to know and love. I rationalized it by putting a connector in the panel, so my handheld radio can connect to the com2 antenna and I’ll carry my handheld GPS. The panel comprises…
EI engine analyser
2 ¼" Manifold pressure gauge
2 ¼" electric tach (don’t have to run a mechanical cable through the firewall)
Navaid Devices wing leveler.
1" Suction gauge
TAS indicator
Electric turn coordinator
4 gauge cluster of 1 ½" Mitchell gauges (Oil pressure, oil temp, voltage and current)
Vertical card compass
Vacuum driven artificial horizon
Sandel HIS
Mitchell clock
Altimeter
3000 fpm ROC indicator
4 gauge cluster of 1 ½" Mitchell gauges (Fuel pressure, left, right and aux. fuel quantity)
6 lamp annunciator
ELT control panel
RS audio panel
Garmin GNS 430 Nav, GPS com
UPS SL60 GPS com.
UPS SL70 transponder
Then on the far right several trim indicators and the Hobbs.
Another area in which I spent several hours pondering was the circuit breakers vs. fuses debate. I eventually decided to go with fuses. The rationale here was that the circuit protection device is there to protect the wire not the load. All the avionics are protected with a fuse anyway, so fuses it is. The design process evolved and the path was…
Still to come is the fuel probe sensor to analog fuel gauge convertor.
More wires…
Now we’re ready to attach the engine mount and nose wheel. But Egads!! The facility is too small. It finally gets to the point where the 25ft airplane will not fit in the 20ft garage. Thanks to Nathan, with his framing background, he whips up a design that incorporates a tarp. I run-off and ask my neighbors if it’s OK. They don’t mind. So, within one Saturday morning Nathan builds the extension…
Now we attach the engine mount. This was relatively straight forward. The results are shown below…
