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gibb -> B25 (1/31/2002 7:42:17 PM)
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I used the ziroli method for all the control surfaces and they all work surprisingly well, however, here is what Iwould do if I built another.
1) Elevators- I used 2 servos driving each elevator- I would'nt change this.
2) Ailerons- 2 servos again- no problems: ( side note: the ailerons are very small and a standard torque servo will work fine)
3) Throttle- 2 servos mounted on the back of the firewall with short and closely matched linkages. Make sure you don't mount them too tight. Let the grommets absorb the vibration.
4) rudder/steering- I used 1 giant servo driving bothe the rudder and the steering. I would change this to 1 servo for steering and 2 mini's or maybe even the new volz servos mounted in the rudders. The weight of the servos are minimal since if you use the pushrod /bellcrank method you have to add all of the pushrods,etc..
5) retracts- 1 servo
6) flaps- I used 1 servo per ziroli and made the bellcrank linkage method: Although it works OK, I would use separate servos for each flap. The linkage/ bellcrank method hides all the stuff internally, but it is just too much work. The positive thing about individual servos is that since the flap are small, you don't need more than standard torque servos.
7) bomb bay- I used 1 servo driving bellcranks. It works OK, but could use more authority since the air flow under the fuse tends to close the doors. They stay open enough to drop bombs.
The roll out is of course up to the headwind and the landing approach, but I have been able to stop it quite easily on both grass and cement. Grass stops are in the 50 -75 feet and hard surface is around 100-200. You can scrub speed easily with a tricycle gear plane. Brakes are not required at this weight. Maybe at 35 lbs+. I don't use more than about 20-25 degrees of flap for landing. It just does'nt need it at 30 lbs.
Heres my recommendations for the building another:
1) Keep the linkage simple and all the scale amenities
2) When setting the engines, concentrate on the linkage being close first then go to tuning. Set one of the engines idles with the carb throttle stop and then adjust the other via the transmitter. That way you can keep the idle settings close. Believe it or not, the idle is more important than full throttle When coming in to land, you really don't want to fight the yaw from asymetric thrust. I also use 15/8 Graupner 3 blade props. They are not the best for performance, however, they are heavy and help the engine idle very well. I have never had a flame out!
3) Keep it light! Its easy to have great plans to add all the bells and whistles, but remember this (101") is only 1/8 scale.
Jim
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