So, I've got this slightly used and abused APM1.4 that I want to try putting on an airplane because it won't fly a helicopter anymore. And I've got a 10 year old 80" Hangar 9 Cub ARF that I haven't flown in 6 years, and I'm not particularly attached to, so I figure it would be a great candidate? It's got a Saito 56 4-stroke nitro engine that has always been reliable and efficient. I don't think it's ever flamed out once after adding an on-board glow driver. This is a balsa, ply and Monocote model, not foam.
I read through the Wiki, but have a few questions:
1. To mount the APM, do I need to worry about vibrations from the motor? This is a problem with my helis, and I'm not sure if I need to worry with the airplane. The Saito does vibrate a fair amount given it's a 4-stroke. What would be the best way to mount it?
2. Since the fuselage is balsa and ply covered in monocote, can I just stick ALL the electronics right in the fuse, antennas and all? Right now it has a 72MHz receiver with the antenna inside, never been a problem.
3. Currently the model has a 4.8V NiCad 800mAh battery pack. Can I power everything with this, or should I definitely go ahead and retrofit with a 2S 2200mAh Lipo and BEC? I'm pretty sure using that NiCad is high up on the "bad idea" list, but just thought I'd check.
4. Ultimately if this worked out, I'd try to put a larger Aux fuel tank under the CG for longer range. With the huge wing, the airplane has plenty of lift, but I wonder about the power. It's well over-powered for a scale Cub in it's current configuration, but can't pull vertical (loops are no problem). I have no idea about how much weight it could actually take up. I'd plan on using some camera gear, etc, as well.
5. Is there any Glo Driver function in the AP software yet? Currently I have a mechanical setup with a microswitch that comes on at low throttle. I'm not sure if there's any point replacing it, but just thought I'd ask.
Replies
Success! She flies beautifully, and the stock params aren't too bad either. I guess I need to figure out the navigation. The loiter isn't great, but I think I just need to open up the radius. But so far so good!
The engine is running fairly well, but I wouldn't try a long distance mission until I get the onboard glow driver working again. I had one flame out.
The 4 stroke vibes seem to cause a bit of "leans" on the ground, but don't seem to affect it in flight. I'll go to softer mounts.
Well, I've got this thing prepped using my APM2-Rx all-in-one. The APM2 is mounted on rubber vibration dampers. I had to redo some of the wiring as the connectors had corroded. At first I thought the servos had gone bad, but I did some troubleshooting and that was it.
I'm a little nervous about flying this thing with Arduplane, as I'm not sure how it will go. The setup seems SO much simpler than a Heli, I feel like I'm missing something!
Since you're into Saito's, they also do lovely boxer-twin engines which will be a whole load better balanced than a single cylinder. This is really what you need for UAVs (or a 3+ cylinder radial 'perfect' primary and secondary balance...)
i would also suggest installing anti vibration rubber gourmets between the engine mount and the firewall. they would reduce the vibrations passing to the fuselage significantly.
5. Could you use a picoswitch cotrolled by your throttle pwm output?
1. Yes there will be vibrations and I would suggest mounting it on something like those little rubber mounts you get inside CD/DVD players to stop vibrations when jogging or make a mount and sit it on top of some moongel perhaps?
2. You will be fine with the electrics inside the fuz
3. I wouldn`t trust the nicad, it probably has oxidised by now? use a lipo and ubec
4.Either install one bigger tank or have two small heli type header tanks either side also as it is important to keep the fuel tank around the same level as the carb.
5.You could use PWM to increase and decrease voltage to the glow plug at different pwms from rc3 so there is a 2 volts at low throttle to 0v at high throttle or just on and off, I expect you would know how to do this as a developer? If not I will try and help or suggest off the shelf solutions