Passion 3D CG
03-25-2005, 10:50 PM
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Passion 3D CG
Just finishing a CMP Passion 3D and have a question about what CG everyone is using...
The manual says to use the range of 90mm - 110mm from the leading edge, which is roughly right on the wing spar... 110mm translates to about 4 3/8" from the LE... Mine is tail-heavy and balances at 6 3/8" from the LE dry...
I started adding weight to the firewall to try and get it to balance and stopped at 10oz... With 10oz of lead on the nose it still balances at 5 1/2" from the LE... The AUW of the airplane without weight is 5 lbs, 12oz... It seems pretty whacky to have to add another pound of ballast to get it to come close to the manual's recommendations...
Anybody have experience with this airframe and what it a reasonable CG without have to carry a boat anchor around for ballast???
The manual says to use the range of 90mm - 110mm from the leading edge, which is roughly right on the wing spar... 110mm translates to about 4 3/8" from the LE... Mine is tail-heavy and balances at 6 3/8" from the LE dry...
I started adding weight to the firewall to try and get it to balance and stopped at 10oz... With 10oz of lead on the nose it still balances at 5 1/2" from the LE... The AUW of the airplane without weight is 5 lbs, 12oz... It seems pretty whacky to have to add another pound of ballast to get it to come close to the manual's recommendations...
Anybody have experience with this airframe and what it a reasonable CG without have to carry a boat anchor around for ballast???
03-26-2005, 09:16 AM
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RE: Passion 3D CG
I used Saito 72 four stroke on mine... Others have recommended everything from an OS .61 to a Saito 100...
There are several build threads here on RCU, just no one ever addressed what they did about the CG...
The only tips I have are to:
1. Use thin CA on everything you can get to since the airframe is put together with White Glue
2. Reinforce the firewall with an additional layer of thin aircraft quality ply, pin it and epoxy over the top to seal it
3. Use two servos on the elevators instead of one with the torque bar
4. Put flying wires on the horizontal / vertical stab to keep the tail from "departing" during flight
The last two items are what pushed the CG back on my airplane, but others have indicated that they have done the same to reinforce the tail section and they wrote that airplane flew well... Do a search in the forums for "Passion 3D" and you will find the other build threads.
Mark
There are several build threads here on RCU, just no one ever addressed what they did about the CG...
The only tips I have are to:
1. Use thin CA on everything you can get to since the airframe is put together with White Glue
2. Reinforce the firewall with an additional layer of thin aircraft quality ply, pin it and epoxy over the top to seal it
3. Use two servos on the elevators instead of one with the torque bar
4. Put flying wires on the horizontal / vertical stab to keep the tail from "departing" during flight
The last two items are what pushed the CG back on my airplane, but others have indicated that they have done the same to reinforce the tail section and they wrote that airplane flew well... Do a search in the forums for "Passion 3D" and you will find the other build threads.
Mark
