Decker79

I sent my Tx and Rx in and it checked out. Now what else could
have caused my glitch and crash? Four servos, 3 s 2200 mah Lipo, and a 25 Rimfire motor.. The 50 amp esc was an internal 5v bec. The wing rocked once then spun left
and went in. Looking for some possible causes.

woodie

ESC failure, ESC BEC not up to the load of the servos, failsafe not set correctly, stall/spin, pilot error, etc. We need more details about the plane, setup, how failsafe was set, antenna placement, battery state after crash, ESC working after crash to guess what might have caused your crash.

Woodie

Jennifer Curtis

A rimfire 25 can drain a 2200 battery
pretty quick. It can also pull it down
too hard.

What was the plane and prop?

The wing rocking also sounds like
a tip stall. Was the plane a warbird?


Jenny

Decker79

It was a flight model mini excellence. The Tx batt showed 6.4 volts and Rx batt showed 80%.
after I got home with it I reconnected everything and I didn't get any response from the motor.
I was using a 14sg tx with a 7 ch r617fs Rx. Failsafe can only be set to throttle in 7 ch mode. Prop apc 11x5.5 esc 50amp 5 volt bec.

Jennifer Curtis

Rimfire 25 is a lot of motor for that plane.
You should have not needed full throttle
much so battery, motor esc and prop
combination should have been fine.

If you did not cut out the cooling air
outlet the ESC could have overheated.

You didn't mention if there was no
response from servos when you tested
after flight. If they work it would be
an indication that the battery is probably
not the problem. You really need a
power meter to be sure the setup is
OK before the first flight. You also
need to check the setup at what
you expect to be the end of a normal
flight to be sure the batteries are not
being pulled down to a low voltage
even though they may have a good
percentage of charge left.

My best guess is that the ESC failed.
If you have done everything I mentioned
it would seem unlikely, but sometimes
they fail for no good reason. Sometimes
little incidents add up and what seems
like no good reason is actually a lot of
good reasons.

Jenny

pilotpete2

You said that the Rx battery was 6.4V, and you'r using an ESC with a 5V BEC??? Can't use both! You would need to disable the ESC if you use a dedicated Rx battery. The receiver you're using provides a user settable F/S on ch 3 and hold last good position on all other channels. Sounds like a tip stall to me too.
Pete

Decker79

The Tx batt was at 6.4 volts. It was going way to fast for a stall. But thanks for your thoughts.

Decker79

The motor was given to me so that's how I ended up with that setup. Cooling wasn't a problem it
always came in after a 5-6 min flight only a little warm. The cooling outlet was open. The servos were neutral after the crash and did work when reconnected later. I agree probably a bad esc. Tell me more about the power meter. Will it tell me how many watts I'm pulling. I've been flying glow and gas since 1979. This was my intro to electric flight. Thanks for your input.

Jennifer Curtis

A power meter will tell you how many
watts and amps your system draws.
It will also show you the voltage under
load, which is what I was referring to
about pulling the battery too low.
Different meters have different bells
and whistles, but these are the most
important functions.

I use a great planes powermatch:
http://www3.towerhobbies.com/cgi-bin...EARCH=GPMM3220

I've also heard good things about wattsup:
http://www3.towerhobbies.com/cgi-bin...&I=LXLMV0&P=ML

If you use the power meter and it saves
you from burning out one ESC it will
probably have paid for itself.

Jenny

Decker79

Thanks I'll look into it.

Checklst

You defiantly need a watt meter....it connects between the batt and the motor. Like you said it show you how much watts/amps the motor is pulling...............my only esc failed on a foamy thankfully it overheated (to many amps/wrong prop)

sjhanc

My Feedback: (3)

There is no maximum speed for tip stalls-if it occurs at speeds well above slow, level stall speed it is called an accelerated stall and can happen at any speed up to maximum. A stall can happen in high speed turns, and at any time a control input moves a surface at a rate faster than the airframe can change pitch, yaw, and in some instances roll. It is usually in the opposite direction of the control input and will result in a crash if a stall recovery is not initiated in time.
An example is the pilot who pulls too hard on elevator for a turn but does not coordinate the turn with rudder to keep the yaw correct for the turn. The result is a stall on the wing that causes the plane to go into a spiral dive while he calls out "I ain't got it". The fact that he keeps pulling up elevator insures that the crash will happen. He goes home thinking the radio is the cause but if he had done a proper stall recovery he might have saved his plane assuming enough altitude.
If his instructor had demonstrated stall recoveries he would have had a chance.

chuckk2

The 2200 is a bit small for a 25. I use an eflite 25 and a 3300mah 3 or 4 cell with a prop change.
I'd also suspect servos. I hope that the 5V bec was not the cause. We found that many did not have enough
peak current capability for some digital servos. Tower Hobbies sells a reasonably priced 5A switching BEC that I've had good luck with.

rgburrill

You said your receiver battery was at 80%. If that was voltage it was way too low. Batteries have a flat curve until they are just about read to drop off then drop off quickly. Any heavy load, even a momentary servo surge can pull a battery down very quickly.
Now, if that was charge remaining ignore what I just said.