Need help diagnosing an odd crash

[PaulH]

I finally got my Gasser dialed in the other day and decided to take it to my field for a full day of flying. That didn't quite happen as planned. I need a few suggestions as to what to look for as I rebuild this bird, because I am at a loss for what could have caused my crash.

I was in a hover, just starting a slow climbout and turning to the left. Suddenly the tail stopped responding and the heli was in a slow left piro. I hit throttle hold, and nothing happened. The engine kept running as if nothing happened. The heli settled to the ground at a slight angle. I never did regain control over it. The idle-up switch did nothing; hold and cut were non-responsive as well.

Damage isn't too bad. I'll need a crash kit, a set of upper frames, and new blades. The engine doesn't want to turn over, so I may have some work to do there.

The Rx and Tx batteries were fully charged and passed a load test. My receiver is a Futaba 319DP (PCM synth). My failsafe is set to kill the engine (had it happen in the past, so I know it works). Servos are 9252 on cyclic, 9151 on collective, GY 401 w/ 9254 on tail, and a HiTec on throttle. I'm using a Dean's antenna mounted to one of the skid supports pointing forward, away from the engine.

Any thoughts? I'll probably be ripping it down tonight and making a shopping list. I just need some ideas of things to look for as I rip it down.

This is the first crash I have had with the Intrepid. :roll:

[Brady Longmore]

Sorry to hear about your crash. That bites big time. I hate THAT! :bomb:

So you had absolutely no control? As if the radio was shut off? Or was it just the throttle hold that wasn't working?

Have you turned on your electronics since the crash to see if the servos and throttle hold are responding now?

[PaulH]

Brady,

Exactly right. I had no control at all. All I could do was watch as it landed (fairly softly), rolled on it's side, and beat itself to death. The engine would not shut off from the Tx at all.

All of the electonics appeared to work fine afterwards. That's why I'm a bit puzzled. I have the battery lead zip-tied to the switch so that it cannot detach. I had that happen once last winter in one of my initial flights with the Gasser. NOT FUN!

-Paul

[Brady Longmore]

weird.

I wonder if a nearby tx caused intrerference.

[PaulH]

That's possible, but there were only two other people in the air, and no one near any transmitting equipment at the time that I could see. I supposed it could happen, but I don't think it's likely.

Fortunately I have some of the spare parts that I need, like both of the gears for the constant drive tail. However I will need a full crash kit, main blades, and upper frames. That puts me at around $300 right off the bat. I'm sure there is more that I haven't found yet. :(

I started ripping it down this morning and found that the pull start will not retract. The starter dog probably broke. I may take this opportunity to get my second gasser finished and in the air. I need a few more parts for it and some servos. I'll just place one mondo order for everything. Hopefully I can finish both in time for our fun-fly on the 30th. :)

The V-Blades web site shows the 720 blades as being discontinued. WTF?

-Paul

[Gyan]

Sounds to me like the receiver crystal was loose or came out. Do you have it taped in? I do. I doubt it was the antennae at such close range. I would send the receiver in for checking after that one! Good luck with the post crash check let us know what you find.

[peter84]

One possibility could be your switch could have only been partial on (not fully slid to the on position) when you took off and the engine vibration caused it to turn off. I had this happen to me earlier this year, thank fully my Bergen was still on the ground.
Safe flying, Peter

[PaulH]

Gyan: I have a 319DPS (synth) so there is no crystal to shake loose. I know the older 309DPS had some major problems, but its replacement, the 319DPS was supposed to have fixed them. Should I send it in to Futaba or Hobby Services anyway? I'm going to have to buy a second one to finish my other Intrepid gasser anyway.

Peter: That is totally possible. I think the electronic components that most of the companies feed us are crap at best. I think I'll be digging into my DigiKey or Mouser catalog to see if I can find a nice, solid switch that is rated for 5A continuous. Even better would be some kind of pin system with a red flag so that I can't do a darn thing until the pin is removed.

-Paul

[Gyan]

Electrotek makes a Gem 2000 super dual rocker switch I use that on my Bergens with Raja's generator & 1800Ma battery on one machine & a dual 1800Ma battery on the other. The switch isolates the batteries for charging & of course the're hooked up to the receiver in parallel when in use. If the receiver is absolutely out of the equation then it has to be the power source, nothing else will do that (that I can think of anyway)