#51
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A Better Mouse Trap
Progress update-
Static tested the new 29mm motor mount. Worked as designed and will allow me to use an F20-3w motor in the Booster/Carrier. The Orbiter will now carry an E15-P. The catch/release mechanism now stays with the booster. I got the idea from looking at the upper half of a clothes pin. The torque on the hinge is provided by small magnets instead of a spring. A forward set attracting and an aft set repelling. Attached to the parachute piston/motor mount is a small clip that holds it all together during boost and coast. In the catch position, drag loads on the Orbiter are transferred to the mouse trap hinge pin and not the motor mount. Hopefully the photos below will help explain. An additional 6" was added to the booster to get the C.G and C.P. to fall into the "stable" range (without adding a ton of nose ballast). Overall length is now 53 1/2 inches. Next launch window will be March 20th. Hope for light winds. Regards, FlyBack Last edited by FlyBack : 03-07-2010 at 05:32 PM. Reason: Launch date changed |
#52
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F20 Boost
Larger motors... a good thing.
Finally got the photos for the March 20th shot. The Booster/Carrier model flew with an F20-4W and the Orbiter had an E15-WP. Booster delay was cut down to 3 seconds. The stack flew as designed with a nice stable boost. Altitude was estimated to be between 450 to 600 feet (based on observer polling). Separation was flawless with the improved "mouse trap" mechanism and parachute deployment was 90 percent flawless. The glider was brought in for a controlled, wings level landing (after loosing it for a split second watching the booster going straight in). The other 10 percent... a 35 cent snap swivel connecting the shock cord to the Booster harness failed. Which ment that the motor mount / parachute piston came down just fine... but the booster augerd. Soft mud saved most of the model (about 9 inches of the forward body tube was crushed). Amazingly, the wing and all the other hard to build parts were undamaged. The nose cone is getting replaced with 8 lb/cuft pour foam, cast in vacuformed .020 in. thick PVC skins (more on that next post). Regards, DJ Miller Photo credit: Lee Spinner NHRC Last edited by FlyBack : 02-01-2011 at 09:48 PM. Reason: syntax |
#53
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F20 Boost
Sorry.. no photos of the wreckage. However the photo below with me holding the motor mount/parachute piston does show the booster harness clearly. The part that failed connects the parachute and motor assembly to the booster. Also attached a few setup pictures with the now destroyed nose section.
Photos of the new foam nose and floating canard will be the subject of the next update. Regards DJ Miller Photo Credit: Lee Spinner NHRC |
#54
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Nice liftoff photo sequence!
Sorry to read about the damage. I love the dual flame. Are you using stock AeroTech Copperheads, or something else? Greg |
#55
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Thanks Greg,
Lee Spinner does some terrific camera work at our launches. All credit goes to Lee for capturing that sequence. Thanks Lee! The damage is easily repaired. I had planned on redoing the nose section after a few more flights anyway. The crash just motivated me to finish tooling for the new parts. I had already done the design work for a floating/active canard that will be used on the R/c booster version. (Very similar to what I did with an Edmonds ECEE Thunder R/c conversion a couple of years ago.) Igniters.. First Fire Juniors only (12in leads). NO COPPERHEADS! No twisted connections either. All connections are crimped or friction fit plug-in connectors. Regards, DJ Miller |
#56
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Vacu-formed Nose
Finally finished the vacu-formed nose cone. All repairs complete. Ready for next launch window.
The new nose and forward fuselage are built from tooling that I will use for the R/c version of the booster/carrier vehicle. It is made from three .020" PVC plastic vacu-formed parts. They are reinforced with molded 8lb density two part urethane foam. The canard flap is designed to "float" up and down for testing on this version. The nose cone has been ballasted to weigh close to what it will weigh with a receiver, battery pack, voltage converter and canard flap servo. The center of gravity has also been adjusted to mimic the dynamics of a R/c version. Assuming I get her back in one ( err... two) pieces, I can finish the CAD drawings and print up some decals. Next update... flight report for the final configuration. Stay tuned, this is the last series of mods planned for this version. Regards, DJ Miller |
#57
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F25W Flight Report
Well, I finally got a chance to fly it with an F25-3W and E15-PW motor combo. Due to a failure of the E15 in the Orbiter to light, and the failure of the hold backs, I made a very important discovery…
The stack flies just fine on just the F25 motor in the Carrier Vehicle. This is huge. It means I can simplify and lighten the Orbiter model by about 25 percent. It also means the elimination of the hold back requirement and about four different launch failure modes. Looks like it’s back to the drawing board… time to build the Mark II version. Until I can get a good start on that… here are some pics of the R/c Carrier Vehicle mock-up. It will initially be flown without the Orbiter. Power will be from two electric motors turning counter rotating pusher propellors. Enjoy. DJ Miller Last edited by FlyBack : 02-01-2011 at 09:57 PM. Reason: syntax |
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