2.4 Interference
 

Twice I've experienced a type of behavior in my EDF's that can't be explained.

Wondering if the high rpm of my inrunner could do it.

The elevator function went full up, with two different EDF's

Only happens with the EDF's at my club field.

Anyone think that's peculiar?

RE: 2.4 Interference
 

Are you running a separate BEC/battery? This the best insurance to prevent brownouts. If this EDF is full house with 6 or 8 servos you can get locked out quick all it takes is one servo binding
Mike

RE: 2.4 Interference
 

What type of 2.4 system(s) are you using?

RE: 2.4 Interference
 

I'm using Spektrum DSM2, and also, four servos, plus the steering servo, all from a bec onboard the ESC. The spec on the 85 amp controller, is 5 volts, 5 amps.

The plane this interference keeps affecting is going to fly again...and soon. It's a HET F-20. I'm moving the RX away from the fan uinit.

The Saab was nailed too. Flew it that day at the field. the CG range is 67 cm from the tail. The Saab after my mods was 66 cm. After field repairs, the cg was forced back to 67 cm by moving the battery. This is a big, long aircraft, and the CG was in range...at least, controllable. The peculiar thing is that there is only one sort of 'splash'. "UP" both planes.

Tail heavy? MaYBE But the condition on both planes for CG range, was that they CG's were both in range, and trimmable by elevator. The planes were built and balanced to kit specifications.

What I'm seeing is that a NON-Pitch-sensitive planform life the Saab, suddenly, VERY pitch sensitive, in only "UP"
What I saw with the TERRIBLY pitch-sensitive F-20, was that it is VERY particular about balance, and elevator throw range, or in other words...a very "PECULIAR" sensitivity.

RE: 2.4 Interference
 

I crashed a plane a few months ago == a TufFlight tiger EDF doing a low pass for a radar gun about 20 feet off the deck. Ground speed was 129 mph. At the end of the run, the plane did a fast "down" elevator and planted itself in the dirt. It may have tried to roll too (ie, snap due to full up on one servo). It happened too fast and was about 400 feet away so I couldn't really tell.

At the time I blamed the action on a control linkage actuator slipping on the taileron axle. I've since silver soldered the linkage for bulletproof security.

I repaired the plane and flew it again several times without issue the latest at the NEAT fair this weekend. After a few low passes, I pulled up high and the plane did an uncommanded snap roll and then spiral before gaining complete control again. I landed immediately.

I'm flying a spektrum AR500, and two HS 85 MG servos, and a Shulman Fury 60 controller which has a switching BEC with more capacity than the servos need. Also keep in mind the loss of control happened when the servos were NOT highly loaded (level flight in one case, gradual pull up and immelman in the other) so I doubt very much a brown out could cause the issue especially since I've done much more radical maneuvers which would draw more current without problems. I also doubt loss of signal is to blame given my failsafe should hold the last known position not a full up condition on only 1 servo.

I now suspect a servo to be the issue and will replace both of the taileron servos before flying again.

Perhaps a servo is to blame in your case as well? Does your F20 use only 1 servo for elevator control? How about the Saab? That might explain unusual sensitivity. Did you guys get the same kind of servo from the same source? (ie maybe a bad batch?)

I didn't think it was possible for a spektrum RX to issue an uncommanded "full up" command during an error condition. It' s much easier for me to suspect a bad servo, but of course I'd like to hear any evidence in this case.

Joe

RE: 2.4 Interference
 

I've had a similar crash with my Raidian. ALL stock equipment. Full down on two occasions. Not flying again with that AR500 receiver. Another club member lost his in the same way.

RE: 2.4 Interference
 

I have had similar problems in the past and have solved it by installing a ubec first off the battery before the esc. It would seem that the esc can combine with servo load to cause a 'brownout'. Maybe coincidence but no problems with any receiver where I have used a separate ubec.

RE: 2.4 Interference
 

Evidence I don't have; I just wanted to add...I received a new DX8 today, and tested, got a 'glitch'. Due to incorrectly allowing the default framerate for my older servos and ar6100 rx.

Thought it was Hitec 'pollution'

Going back to the DX7...when I fly I can note aerodynamic discrepancies vs. (other) various discrepancies. (pilot error...lol) In all seriousness, based on my observation, someone's gotten a fly into the ointment. Without really knowing it. Cell tower signals. Although the rx's can filter sometimes they have to go 'hold'.
It's not outside the realm of possibility that some holds can receieve code.

RE: 2.4 Interference
 

Two elevator servos for the saab, one in the het.

Incidently, I still had aileron control, IE roll axis. The Saab's elevons were functional enough to do a half roll, to save the plane. The mixed bag of tricks seems to be the elevator signal, and that leads me to feel my transmitter is failing.

RE: 2.4 Interference
 

Could be a bad pot on the elevator stick/poor solder conection (pot to circuit board)

RE: 2.4 Interference
 

Only happens with EDF's, only at WFC

RE: 2.4 Interference
 

So is it better to used a bec with its battery ??????????? working on a b52 with eight motors going to used my DS7 had a 9000 recever go bad not sure about spectrum

RE: 2.4 Interference
 

My TX is at question as well...have some issues with it, because it was bought Second-Hand.
However, the problem was showing up as full up elevator ( Tail-heavy )...neither was pilot-error. Tail-heavy is a condition that limits pitch trim and makes a plane uncontrolled at low speeds. As long as there is airflow over the elevator I should have been able to stabilized the plane and land. Both planes were in a CG range suitable for the design, and incidences were according to the kit.

So I have some electronics issue at hand, with a peculiar condition...high-rpm inrunners, and a specific flying location. So if I miss my guess, we have an unwelcome guest at WFC with some "2.4 splasher"...

The unwelcome guest could be high-tension power lines, other radio transmissions, or simply a re-curring glitch in the TX. I will continue to test the TX in actual use...in a safe area.

If you're using a B52 with 8 "Motors" I would filter the bec on the speed controllers, with 1000uf capacitors on all 8 controllers.

Again, a bec issue with the EDF's I have to eliminate...I MUST use a filter cap,,,