erratic flight
 

After several fantastic flights with a PZ Super Dec., today it decided it had enough of flying. I hand launched as usual, full throttle, slightly nose up, and it went nowhere. The plane started to drop, and I added a bit of up elevator- nothing, it just dropped out of the sky from about 10 ft. I flared it a bit and was able to land "rough". After a brief inspection and control test, I tried it again. This time it climbed to about 50 ft, and I started a left turn around the pattern. Again, it lost altitude and This time it nosed in from about 5ft. The plane is undamaged, and the control surfaces are all responding as they should. I flew two batteries through it yesterday and all was well. What could have caused this? Any suggestions? I have a new prop on the way: a 10x4.7 as recommended in the RCU review. I'm wondering if I should even try it?? -Paul

RE: erratic flight
 

Hmmm a complete loss of control when in flight, after days of perfect control followed up by good ground checks....

To me; it sounds as though something electrical has worked itself loose.

It is making connection on the ground but it breaks down in flight either from the increased demand or from the vibration... either way double check all wires and connections.

As a last resort send the receiver off to the factory rep. for an inspection - it could be an intermittant receiver....

Good Luck!

RE: erratic flight
 

bbbair,

When I got home, I went to check the control surfaces again, just to make sure nothing was loose. Comfirmed, all is solid. I did notice a bit of "chirping" from the Rx. Sitting on the table, with the Tx about 3 ft away, it acts as though there are "micro inputs" to the Rx. I see the rudder jerk ever so slightly to the right or left maybe 1-2 mm. The elevator also moved, but not quite as much. I can't see that such a slight movement would have caused such a lack of control, unless my inouts were not reaching the plane at all. The control surfaces DO respond to my commands so it's something I should have been able to compensate for. I'm going to remove the wing today and see if it's warped, as I've read it's a common problem with the Parkzone Decathlon. I'm also going to pull the Rx, and double check the jumpers. What boggles me is that just 24 hours earlier, it flew fine! Landed without incident, and was parked at home while the batteries charged as usual. Then this...it defies logic. I'll keep you posted on my findings.

RE: erratic flight
 

Have you tried tapping on the receiver to see if the controls do strange things from the vibration?
Also check to see if the transmitter antenna has become loose or unscrewed.

Get someone to help, and do a good range check on the radio - see how far away you can get and still have control, with and without the motor running.

You may also have a problem with the battery charger.

If you do have to send it in for repair, it would probably be best to send it all so they can check it out - transmitter, receiver, batteries, battery charger, etc. Electronics can fail suddenly, or even develop a crack in the solder connections (resoldered lots of those in my former job working on audio equipment).

RE: erratic flight
 

I'm guessing the motor & or the geabox is the problem. You stated after several fantastic flights, and that you have good control surface control on the ground everything is doing what it is supposed to yet at full throttle it it won't stay in the air. Brushed motors & cheap plastic geared gear boxes both have a very short lifespan. Again you stated that all control services are functioning properly in the air too, you just don't have enough consistent power to keep it from stalling any more. I'd be willing to bet that the brushed motor is heading south or the gears in the gearbox are stripping out or both.