stratus crashed again and I have no idea why

[jambo]

A few weeks back I added a viperhead and OMI big bore carb to my no.1 stratus. 2-3 minutes into a test hover the heli flipped over into the ground. Previosuly it was flying fine. On the bench I could find nothing electrical or mechanical to cause the problem. Becuase the elevator servor was locked on full back I assumed the servo was dodgy and replaced it. The heli didn't glitch or go into failsafe. In addition I replaced my duralite 4000 battery and regulator with the same type of battery and a regualtor with a failsafe switch. I checked all the bearings and they were fine except a couple which were caused by the crash.

Today I took my rebuilt stratus to the field to test fly, the first half a tank was just running the heli up on the ground for a few mins but not enough lift to take it off the ground. I checked the heli over back in the pits and it looked all OK. The second flight I then started to lift the heli off the ground about an inch and instantly she went over on her side and crashed again :mad: It happened so quick that I'm not sure what happened, it didn't glitch and I don't think it was a lockout as my failsafes are set to hold everything and set the throttle to idle. If it was a lockout my heli would of just dropped to the ground wouldn't it?

The first crash cost me about £450 and by the looks of the second crash its going to cost me about the same.

I don't really know how to go about finding the problem which is the bummer! Everything looks fine on the bench after the crash, the electronics seem to be doing what they should.

My 14mz radio is not at fault because I have been flying my other heli with it and it wasn't shot down as I was the only person at the field.

I can't really justify throwing away £1000 of electronics and replacing them so how do I go about diagnosing this issue? I also can't justify testing the heli without finding the fault now as its going to cost me upto £500 each time let alone the rebuild time which is more valuable to me than the money.

I'm really really stuck on this one :arggg: and your help and experience with these kind of issues would really help me

Steve

[angelob]

My fury went in the other day...I was in a 10ft hover when the heli made a sudden jerk to the right and stopped. I hit throttle hold and on the way down I lost all control. I was lucky it had been raining a lot lately and made the ground softer. Anyways, I powered it up on the bench and it was fine so I fiddled around with the wiring...turns out that I had a voltage regulator problem. Peeling off the heatshrink revealed that one leg on the transistor had broken and was making intermittent contact. Just something to possibly check.

Angelo

[jambo]

turns out that I had a voltage regulator problem. Peeling off the heatshrink revealed that one leg on the transistor had broken and was making intermittent contact. Just something to possibly check.

Angelo

I will check that but it had a new regulator in it the second time. I'm assuming that I would be very unlucky to have two faulty regulators but you never know!

[WayneBrown]

You carry a cell phone? maybe it's proximity interference?

[jambo]

You carry a cell phone? maybe it's proximity interference?

no i never carry a cell phone when i'm flying

[flyinfool]

Which RX are you using.
Some of the 1024 PCM Rx have had power buss issues.
I am currently going thru the exact same thing.
I am putting in a different RX, reg with FS switch, and batt.
I was able to get one very short power interruption after a half hour of wiggling and jiggling, it did not last long enough to identify the source and I can not get it to do it again.

That RX reg and bat are going to spend some quality time in a Zagi.

In my case I was very fortunate that the power went out just as the heli was spooling up and everything froze while the throttle was at around 50% and the pitch was still around -2 or -3. I just had to stand in agony waiting for a full tank to go away.

[jambo]

I am using the G3 receiver that comes with the 14mz. I have done the tapping, wiggling stuff for about half hour and can't get the heli to do anything out of the norm :arggg:

[Alfred]

Jambo
The Stratus is all CF. So mechanicle/electrical noise is a large issue.
Check everything throught the heli to insure that nothing is loose. i.e..all the bolts..skids...
Get a cheap 7 channel PCM receiver and a straight 1700mAH SCR 4 Cell Battery and test fly it with that.
When all is well, replace the Receiver with your G3 one....still all good?
Now put back in your regulator.
I would get one of those cheap foldable workbenches where you can screw the top halfs together to use as a vice. You can get them in Handyman Stores.
Some large strong cable ties....
A couple of bags (hashenbags) full of sand to weight down the Workbench, tie the heli down onto it and start doing range checks, go from idle and work your way up to just above hover.
Do this after you replaced the items with the ones above, and fly.
Now change one item at the time, back on the workbench, all OK?...fly it...OK?,change next item...and on and on.
It might be a pain in the a$$ but at least it will get you to find the real problem without costing you another fortune in parts.

My stratus is just about finished and for the 1st time, I have just purchased my very first LiIon battery going with a Arizona Dual Regulator. The battery is 4800mAH and should give me some flying time :lol:
But mine will start life tied onto the Workbench and range checked as it also will have my my 1st shyntesized receiver in it.

Hope you get it sorted soon :roll:

[Rada70]

I had similar problem. What caused mine was the gap between the clutch driver and the fan was very small. Specially since the stratus flexes in the air it caused the RF (metal to metal). You should take out the fan and look at the top of it. check for any marks.

[jambo]

I think I have tracked down the problem to a 9255 aileron servo, if I push the back of the servo it does some funny glitching and if its not glitching it has no torque, I can move the servo wheel by hand whilst the power is on with no effort and then when i let go the wheel will go back to its normal position I have checked the receiver channel and other servos on that channel are fine. Its only a few months old! I'm going to send all my electronics off for a check over I thinks!