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TM4197
03-23-2010, 03:47 AM
Well, I need some help here guys. I was flying a Electrifly Sopwith Pup, and I must say...what a beautiful plane in the sky....I was at 1/2 throttle, perfect level flight 10 feet off the ground, and then the throttle went to full power. I tried to clear it by throttle control, no dice. The plane torqued over and slammed the ground. I've never seen more foam explode in my life. I was flying alone. I took all the gear out and bench tested. I can not get the throttle to duplicate what happened. I went out to the field and tested it there as well. Anyone had this happen and find anything other than interference? I really hated loosing this one.
Equipment: without naming brands..The equipment was "recommended" gear.

degreen60
03-23-2010, 09:31 AM
If your not going to try to repair the plane I would love to have the pieces. I have never had a throtle go to full power. Also no matter how low my planes are full power just causes plane to climb. I think you had interference. Probably the rudder and elevator went out of control to cause the crash.

tobydogs
03-23-2010, 01:54 PM
i was thinking along the same as tm,i used to fly at a ball park ,all would go great and wham....down and crash.

it wasn't 2.4,but 72mgh and i began to wonder if someone was searching channels and shooting rc's down.

it could'v been radio interfearance also but now i only fly at the club.

most of my crashes are dumb thumb.....lol.:blah:
sorry to hear about your pup,hope your flying is going well now:).
stu

MaxAdventure
03-23-2010, 02:12 PM
Well, I need some help here guys.
........
I was at 1/2 throttle, perfect level flight 10 feet off the ground, and then the throttle went to full power.


Very limited information. How far away was the plane? what structures were there? Was it an established RC field or a cow field next to a cell repeater?


I tried to clear it by throttle control, no dice.

Not sure what this means; I know I've momentarily tapped the throttle on my track car and my carburetor cars to clear excess petrol that has built up, but I'm not sure what you mean by this for electric flight.


I took all the gear out and bench tested. I can not get the throttle to duplicate what happened. I went out to the field and tested it there as well.

what did you do to test it? did you place the RX in the same location with the motor running as when the event occurred? Was the battery still attached and the system responding when you went to pick it up?


Anyone had this happen and find anything other than interference? I really hated loosing this one.
Equipment: without naming brands..The equipment was "recommended" gear.

Without naming brands, I think diagnosis will be next to impossible without knowing the technology: What radio band are you using? 50mHz? 35Mhz? 72Mhz? 2.4Mhz? Is the radio computer or analog? PPM or PCM? Did the receiver match or was it an off brand? What was the radio power source? I've seen everything recommended, so that doesn't really narrow it down.

Why does it matter?

Low voltage will cause servo twitching, and I've seen it affect different technology differently.

Lower frequency bands have more 'punch' while high frequency bands can be shadowed easier.

Lower frequency bands are more susceptible to generated interference from conductor on conductor vibration.

Some technology has fail-safes, and if the RX is triggered into fail-safe and it's not been set correctly will cause something like this.

Some frequencies are shared.

yes, I've had most of that happen to me at one time or another.

TM4197
03-23-2010, 06:55 PM
MaxA

I was flying 20-30 yard cicrles, 10-15 feet off the ground. A school yard that I have been flying in for 20 years..no cell repeaters.

I meant by clearing throttle: Moving the throttle stick up and back, there was no response.

The gear was still operational after crash at the site. The battery was not hot, motor was still hot to the touch. I took the fuse and gear home in tact and ran through all movements, with no jittering. Motor responded to all settings. I then took it back to the location of the crash, let it sit for 20-30 mins in the on position, I worked the throttle in all movements of the stick. No jittering and motor rsponded well. Did a range check, no issues.

I will not name brands here. I know it makes it harder to diagnosis, but I respect the company brand I use, because its all I use in all my planes and have had no issues, if my research finds the product suspicious? I'll name brands. I use a 72 Mhz PPM which had fully charged batteries. I had a 2cell lipo 750. Run time was approx 6 mins. The receiver is not matched, I use 6 of this same Rx in other planes and have no issues. A new bell style motor, 3 wires with new Dean connectors.

Thanks for the questions, I find it better to wait for the questions rather than just load the initial thread up with data. Right now, I really feel like I got interferance.

dbcisco
03-23-2010, 07:58 PM
Did you check if any links or horns detatched? Any control hinges come loose?
Other than the motor racing, which should have made it climb, the roll and dive sounds like control surfaces problem(s).

MaxAdventure
03-23-2010, 08:14 PM
Thanks for the questions, I find it better to wait for the questions rather than just load the initial thread up with data. Right now, I really feel like I got interferance.

fair enough!:)


I will not name brands here. I know it makes it harder to diagnosis, but I respect the company brand I use, .

I can appreciate this, it's just a shortcut to know. However I like the idea of NOT naming, so there can be no presupposed finger-pointing! :D

MaxA

-A school yard that I have been flying in for 20 years
the throttle stick up and back, there was no response.

The gear was still operational after crash at the site.

was the battery still connected? I've had a couple of crashes where the battery worked loose in the air. An intermittent connection can cause a low voltage causing loss of signal, jittery signals, and fail-safes

I then took it back to the location of the crash, let it sit for 20-30 mins in the on position, I worked the throttle in all movements of the stick. No jittering and motor rsponded well. Did a range check, no issues.
I use a 72 Mhz PPM which had fully charged batteries. I had a 2cell lipo 750. Run time was approx 6 mins. Right now, I really feel like I got interferance.

so, it sounds like a very thorough equipment check, which I would agree sounds like interference. A high-powered transition locally can walk on a signal , I wish my dad were still around and I could ask the technical details behind it, but I know it's a wavelength factor. It may have been a chance occurrence of an amateur radio operator driving by? without being able to log the signals, I think that random interference may be our best guess. I'm by no means the smartest one on here so maybe someone else will chime in with good ideas.

MaxAdventure
03-23-2010, 08:22 PM
the throttle went to full power...... The plane torqued over and slammed the ground.

Did you check if any links or horns detatched? Any control hinges come loose?
Other than the motor racing, which should have made it climb, the roll and dive sounds like control surfaces problem(s).

I'd go with the OP description, he saw it happen and knows the plane! big prop on low KV will torque a short span (bipe) plane quickly!

as a side note to your control surface suggestion; I lost a plane last fall due to a screw I thought I'd put lock tite on, vibrate out of the aileron servo (metal output shaft). The linkage fell back in the wind and threw that aileron to full deflection, twice what I had set up and I couldn't counter it with the other aileron. *sigh* nothing like a maiden to show you what you missed on the build! Took me a month to get over it and go back over the pieces to see what happened.

TM4197
03-23-2010, 10:42 PM
The control links were still holding on to dear life when I picked her up in pieces. (DEGREEN60) I'll hold the parts for you next time, Ive seen what you can do with them. Ok, I went over everything one more time, and I found the NEG wire on the lipo was not soldered inside the casing, the wire could be pulled out with no effort. However, it was inside the caseing. Now, is that post crash damage? who will ever know? I placed the NEG wire in and turned on the gear...no jittering. The motor ran fine. Pulled the wire out slightly, but not out of the case..nothing would work. So, if the battery wire came loose in flight, would that cause the motor to go to full throttle? I would like to clear up about the torque. She spun left like 2x full left aileron the instant the motor went to full throttle. As we know, this PUP has no aileron. Thats why I was so surprised. I was in a left slight cirle turn, holding about 20+ feet. So, I guess the left skidding turn at slow speed and full throttle rolled her over. :confused:

dbcisco
03-23-2010, 11:09 PM
My sympathy on the crash.

But it is a neat trick to be able to do a torque roll with one of these.

TM4197
03-23-2010, 11:16 PM
yeah..but for me it was like hitting a hole in one at the golf course ....playing by myself! Another pup on the way, just to much fun not to have one..!

park
03-23-2010, 11:53 PM
It wasn't made by Toyota was it ?

ministeve2003
03-24-2010, 12:19 AM
It wasn't made by Toyota was it ?


Toyota....

now thats funny right there...LOL

SK

degreen60
03-24-2010, 12:50 AM
For motor to go to full throtle it would need several frames of 2ms pulse. I am guessing that all channels got several frames of 2ms pulses and therefore the servo went to max deflection which would cause a spirel into the ground. No pulses either solid carrier or no carrier should cause the motor to shut down and the sevros to either lock in position or glitch depending on how the receiver is built. If another transmitter was turned on and on the same freq it could cause the receiver to see longer pulses and cause the motor to go full power, servo to wrong position, crash. It would only need to see the siginal from the other transmitter long enough to crash. With out doing some research I do not remember if weather can cause 72mhz to travel long distances, if it can it may have been something that was only there a few min. Another thing that can happen but I would not think would be long enough to cause this is for your transmitter siginal to bounce back with a delayed siginal, adding the 2 siginal together makes a long pulse but I do not think this would last long enough to cause full throtle, usally just a glitch.

Bill G
03-28-2010, 08:09 PM
It wasn't made by Toyota was it ?

I wouldn't put anything past an Electrifly ESC, if that's what was in it.

I understand what the flight was probably like, when it went to full power.
I was fortunate when I took my Guillows Sopwith Camel to full power, after installing a new motor. The first motor was underpowered, or at least overworked for the app, but the plane flew well up to full power. With the new motor, the plane went into fast, uncontrolled rolls when pushed to full throttle. After cutting the throttle, I manged to recover by mostly sheer luck, at low height. I would have been ticked to lose this plane. I know not to give it full power now, and it flies fine. Even took a video after the event, which is on You Tube under you guessed it, WTFLYR.

TM4197
03-28-2010, 08:39 PM
Nice looking plane! Gotta love the sky when it looks like that ..perfect background. Mine happened incredibly fast, could not hardly respond other than throttle, which didnt help. Just finished another one. Of course we always tweek after the first one. Pretty sure now, it was the battery wire. HAPPY FLYING!