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SS1 4-inch RC Boost Glider
I decided early on that I would NOT be the guy to pilot the SS1. I needed to find a willing and slightly crazy hobbyist who understood both rockets and RC aircraft. I found him at the local NAR club, the Superstition Spacemodeling Society.
Gerald Meux became my scapegoat RC consultant. He is the one I will blame if anything goes wrong thank with each successful flight.
I was hoping that I might be able to rescue Gerald from the unsavory influence of those degenerates at Hillbilly Roketry. I'm afraid that he has been associated with them for too long and the damage will prove to be irreversible. We'll see.
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At left Gerald is posing with his 4" diameter upscale Estes Maniac. The rocket above is his famous Arizona-themed level-3 rocket, a 10" diameter Nike Smoke.
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I got Gerald involved in the SS1 project about the same time that I built and flew the 4" test glider. Since I'd already built a working rocket and a working glider, the next logical step would be to build a 4" rocket-boosted glider. It was Gerald who suggested that we add micro-servos and actually make it into a radio-controlled vehicle. I was pleased with the idea that the pilot would have the opportunity to practice on a smaller version of the same design.
I made a set of parts, and Gerald and I cobbled together a version of the 4" test mule that was heavier than the foam glider but lighter than the all-fiberglass rockets. We decided that we would have an ejectable motor pod like the 1/4 scale rocket, complete with nose weight that was ejected at apogee. The construction details are noted below.
Pre-Flight Testing
To the right, Gerald is preparing the boost glider for one of our early tests prior to actually flying it with a motor.
The first flight test was pretty much a bust. Basically, Gerald did what I did with the foam glider and gave it a hefty toss — but the rocket wasn't balanced correctly and it had a rather undignified landing. In other words, it crashed hard. This messed up quite a bit of Gerald's work, including a broken servo. But Gerald was undeterred, and he soon had it repaired and ready for a second test.
We rejected most of the advice we received about what the second test should be (including the suggestion that we fling it from a giant slingshot).
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For the second test we decided we would fly it the way powered model planes were flown back in my youth. In those prehistoric times hobbyists used to fly control-line model airplanes in a giant circle, tunring around and around until you got so dizzy that you fell down or threw up or both. But for this test, I would swing the SS1 in a wide circle while Gerald would fly it with his RC controls. It worked.
We attached the line at the Center of Gravity (CG). with a screw eye driven into the edge of the wing. Not only did it fly with the predicted stability, but Gerald was able to control the flight attitude and altitude.
Rocket-Boosted Flight #1
Gerald and I made a special trip out the Rainbow Valley to fly the RC boost glider. He loaded in a G64-7 with the delay trimmed down to (he thought) four seconds. (It was closer to six and should have been two.) We loaded it onto the pad. I manned the video camera while Gerald worked the launcher and the RC controls.
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Not pretty, but functional.
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Also not pretty, and mainly dysfunctional.
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Was the flight perfect? No - but we learned some things that we wouldn't have learned form a perfect flight, so that made the experiment a success.
For example, we had tried a way to lock down the elevons during boost — one of the elevons stayed locked, causing the glide to be sub-optimal. So we made some inquiries afterward, and learned that locking down the elevons was unnecessary. And in addition...
- the boost was good
- the motor pod ejected as planned
- the CG shifted as designed, and
- the glide was OK (right up to the harder-than-planned landing).
...all of which taught us something about how this glider is supposed to work and how to get ready for the next test!
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Click [HERE!] for video.
Construction Details
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Lightweight aluminum tubing fits in a slot in the honeycomb Nomex. This is the pivot arm for the control surface.
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The aluminum tubing is epoxied into place and held with a clamp while it cures.
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This collar holds the pivot arm in place.
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The pivot arm extends through the vertical stabilizer.
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The pivot arm from each horizontal stabilizer slides smoothly inside a slightly larger tube that extends between the two vertical booms.
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By connecting the opposing stabilizers together we created a strong and lightweight pivot mechanism that needs no additional reinforcement.
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This cavity in the edge of the wing fits the servo. The wiring harness runs through the wing, into the fuselage, and out the forward bulkhead.
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This photo doesn't show much, except the incontrovertable evidence that Gerald is a bachelor. No married man could epoxy his rockets on the living room carpet.
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Servos, and control arms installed.
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Opposite side
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We used PVC to extend the core tube all the way to the front of the nose cone so the boost ballast can be placed as far forward as possible.
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The ejectable motor mount slides inside this core tube. The boost ballast will be attached to the motor mount, which is also extended to reach all the way to the front of the core tube.
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The motor mount extension (which holds the lead boost ballast) is made out of copper. These sturdier materials were used because they are easier to mount firmly than paper tubing, and the lead ballast needs to be held in place in a solid fixture.
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This weird photo looks into the aft end of the motor mount and out the front. The hole in the center got plugged with lead. The copper tube is centered in the motor tube by three blocks of wood. Ejection gasses pass through the spaces between.
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The battery pack and receiver are mounted in the nose. Note the additional weight attached to the core tube cap.
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These wires are the antennae for the receiver. Don't ask what that silver thing is in Gerald's hand because I don't know either.
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The lead weight installed in the motor mount extention. Also notice the way the copper tubing is centered in the motor mount tube, and the spaces for the ejection gases to pass through.
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The motor mount is partially inserted into place in the SS1. To reiterate, this pod ejects along with the nose weight in order to reduce overall weight and shift the CG for the glide phase.
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INDEX
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