Puzzling Crash

[pgkevet]

[B]Yes, my beautiful newly owned Blitx went down[/B]

It's got me puzzled..perhaps when I take it apart there will be some clues but I doubt it.

Second flight of the day with it. Part way in and all i was doing was basic stuff and some flips and loops then flipped it to inverted hover about 20-25 feet up and it came down hard despite me giving shedloads of negative.

Obvious first thought was that i wasn't in idle up..but I was not only in idle up but in idle up 2. And I've double checked tx and all the curves are correct, correct model selection. When it hit the deck (hard on it's head) the engine was still running (belt had come off on impact?) and the engine shut down in response to the tx promptly..so still communicating..and if it hadn't been then failsafe should have kicked in and I had checked that on preflight.

I have no explanation at the moment and I've crashed enough not to hide from when it's my fault..

All the usual carnage to take apart and re-order but I will say it took the thump remarkable well.. canopy undamaged and skids OK.. did leave a serious hole in the park..Radix obviously cut good divots:(

boom, torque, tail pushrod, mainshaft, spindle shaft so bent it squeezed the dampers out and cut them, grip arm , mains and tails, flybar, horiz fin are obvious...sure there's more to find.. expect servo gears etc.

Apart from the blades at least it's british economy help...

[Mslater]

Sounds like a brown out - Are you on FASST or Spectrum

[pgkevet]

[quote=Mslater;538070]Sounds like a brown out - Are you on FASST or Spectrum[/quote]

FAAST 12FG and I don't believe it was a brownout..no servo judders etc. I've never had a brownout of my own and the rx came off another heli of mine that's never had a problem. I will be checking all the wiring but that's new and still temporarily routed. It would have had to be a transitory total power failure that crrected. Before I owned it it ran spectrum so if the belt was a source of trouble it ought to have shown up then!

All tx switches work right ans checked their function on the servo output monitor..

Add bls251 servo gears to the list and the crown gear so far..

[trillian]

Oh no! I hate to hear of the Avro going in. One of my much loved Robbe Futuras went in very hard a few weeks ago and I still don't know exactly what happened, try as I might to remember any defining detail (and I honestly don't crash very much so I can recall all my previous crashes and the causes). It's extra annoying to not know the cause.

[daren]

Are you 100% sure you have a V curve on the throttle setup in the tx and that idle up is enabled?

[pgkevet]

[quote=daren;538166]Are you 100% sure you have a V curve on the throttle setup in the tx and that idle up is enabled?[/quote]

Yes..and confirmed by looking at the servo monitor outputs. It also wasn't the first time i flipped it that flight..but was the first time that flight that I held it inverted..but I had held it inverted on the prior flight.

It's why I find it puzzling..and that's why the first thing I checked was idle state. Also no governor on this model so couldn't have been masking a poor throttle curve.

I've also just checked the wiring and servo responses to tx on the bench (now the shafts are out) and everything has bags of power left and works fine. Plus I'm pretty anal after some beginner errors and crashes with expensive gassers and this heli had a full checkover of all links and moving bits and a full range check prior to it's first flight today.

All I can do is finish the search for bent bits, order them up, fix it and then fly it a while on cheaper blades to see if there's a repeat.

It doesn't have a header tank but does have a fuel magnet and a crank pressured system..but it wasn't a flame out. Heck I've flipped my 700N in idle down and had to do an inverted auto onto the headbutton because I thought the engine flamed out (doh!)..my idle down curves have enough negative to slow descent (-5deg).

This slammed in like I was giving opposite pitch (no I wasn't..)

[pgkevet]

Add bent tail output shaft, one cracked skid bow and cracked bottom plate...
I've also found some bits that could do with servicing that were deeper down than i went on it's service when i got it...might as well take the opportunity to do a total refurb while I've got it this far apart.

There is some great engineering here: for which you can read that the parts count is a bit higher than I expected (but not as high as my Spectra).

No wonder it flew so smooth and tracked perfectly..

I suppose if it was redesigned it could be simplified by using some of the current trends and perhaps made a little more crash friendly and the alloy parts blinged up. If it was then it'd deserve to be right up there with the more popular high end models on numbers.

It's superb as it is...but just think...