Stripped secondary gear during full pitch climb out

[aziz76]

Took my TDR out today after doing some maintenance (I replaced 3 bearings on the bearing blocks that were a little notchy) and everything was going great until from a hover, I did a full pitch climb when suddenly i felt it lose power. I auto rotated down but with my auto skills it wasn't pretty . Managed to break the lower frames, tail blades, and a boom strike. Mains are surprisingly ok. The crown gear was partially stripped too, though I suspect thats from the tail hitting the ground.

I wondering though how this could happen. I have the heat resistant main gear (no damage at all), But the secondary gear (the one on the main shaft), completely stripped. My motor is a Pyro 700 Black Edition.

JLog showed pulling just over 130 Amps when it happened, not crazy high, I have had spikes like that before with no issues.

Anyone had this problem before?

[Paulice]

Yes it happens to me a lot, but i'm pulling a lot more power then you, but still you have the Black line motor that has a lot more power than the standard unit.
I had one go last weekend and again on the same heli yesterday, But i'm using the heli for drag racing at 2600 RPM and 17° pitch.

What is very important is lubrication on all the gears, if they run dry they heat up and then the teeth go and you know what happens next.

[xioxia]

Cant believe pyro700 is reason behind this

I did first flights with 6s 5000mah packs and it was
ludicrous unpowered...

upg motor soon!

[aziz76]

Thanks for the input Paulice. I had just greased the gears before that flight after the rebuild, and I am running 13.5 degrees pitch. But I guess the motor power combined with the sudden collective input did it. Jlog showed a power spike of 5400 Watts!

[Vinger]

We must all realize that Jan designed this in 2008/09 and for a maximum of 4500W, so with all these powerful motors and better batteries we are using it beyond design specifications, no fault of the heli!!!!

[aziz76]

That's a good point. I will be working on repairs today. Hopefully the damage isn't more than what I found in the first inspection and also hope I have all the parts on hand.

[waxman]

Originally Posted by Vinger

We must all realize that Jan designed this in 2008/09 and for a maximum of 4500W, so with all these powerful motors and better batteries we are using it beyond design specifications, no fault of the heli!!!!

He has also made updates to the heli since it's release to accomodate more power, let's not forget that. The heli is more than capable of handling the power from a 700bk pyro.