Hawkman
Senior Member
Posts: 797
Loc: Falklands
Reg: 03-18-05
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01-09-08 12:54 AM - Post#86042
Hi there, both horizontal stabilser bolts have now snapped on my Predator 231 gasser...one was missing the other day...coming in to land the support stay was loose...taped it up and carried on flying...replaced the bolt after getting home.
I noticed the other bolt was missing after an inspection today...replaced this too.
I might have done them up a bit tight before...so they are not so tight now...has anyone had this happen to them? I am going to fit stainless bolts sometime soon.
I had a bolt shear on the skid struts...I removed the bolts and spacers recently and rethreaded to take 4mm stainless...works just fine.
I must say, the Predator has been a great heli so far. I am clocking up the hours as much as possible now...I try to get at least 30 mins per day...when at work I use my little Trex 450 to provide a 'fix':)
Rob
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reddragon
Full Time Senior Member
Posts: 3870
Loc: Brooklyn, NY
Reg: 01-22-03
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Re: tail stab clamp bolt failure?
03-01-08 03:15 PM - Post#86478
In response to Hawkman
Rob is stainless steel "softer" than the standard steel? Someone check this for me please.
If you tighten a bolt too much and load it with vibtrations there is a good chance that it will sheer off at the thread.
-Wayne
Fly it like you stole it! |
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Hawkman
Senior Member
Posts: 797
Loc: Falklands
Reg: 03-18-05
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03-02-08 04:03 PM - Post#86484
In response to reddragon
I am not sure on that one, the mod has done the trick though...not a breakage since.
Whats interesting though is this, one of the main frames has developed a crack...its on the right side and from the rear of the frame about 3 inches or so forward...right above an allen bolt that goes through the frame and into the engine crankcase itself.
Have to get me a turbine:)
Rob
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reddragon
Full Time Senior Member
Posts: 3870
Loc: Brooklyn, NY
Reg: 01-22-03
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tail stab clamp bolt failure?
01-01-09 02:42 AM - Post#87403
In response to Hawkman
If you tighten a bolt too much and load it with vibtrations there is a good chance that it will sheer off at the thread.
By the way .... this happened to me a few months back with my Raptor 60 and the Main Shaft Bolt. A good piece of the threaded portion along with the nyloc nut were missing after a flight. Normally I don't tighten the nut and bolt too much. It may have been metal fatigue as this was the first time it happpened to me.
Oh the horror. 
-Wayne
Fly it like you stole it! |
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Hawkman
Senior Member
Posts: 797
Loc: Falklands
Reg: 03-18-05
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Re: tail stab clamp bolt failure?
01-02-09 11:08 AM - Post#87406
In response to reddragon
Hi there Wayne, hope the New Year saw you without a hangover?:)
Well after a long time not flying the Predator I am back in the saddle again.
The fractured bolts, plus a cracked frame...and even a cracked crankcase (its not chronic) the cause could well have been too much power.
I got some advice from another site that has a gasser Guru or two, I have revised the power curve a bit and the vibes that plagued the tail gearbox and vertical fin have gone!
A much smoother machine, I had the engine out too so as to recheck the fan and clutch alignment and balance.
Maybe a stainless nut and bolt set for your 60? or high tensile steel?
Shows that you must inspect your machine well...good for you.
Rob
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Phil Noel
Senior Member
Posts: 303
Loc: Canada
Reg: 02-19-03
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Re: tail stab clamp bolt failure?
02-24-09 11:46 PM - Post#87490
In response to Hawkman
Rob
Glad to see you were able to find some gurus on another forum that were able to help you out.
Now it must be back to burning fuel (gasoline).:)
Phil
Edited by Phil Noel on 02-24-09 11:47 PM. Reason for edit: No reason given.
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reddragon
Full Time Senior Member
Posts: 3870
Loc: Brooklyn, NY
Reg: 01-22-03
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Re: tail stab clamp bolt failure?
05-08-09 11:49 PM - Post#87571
In response to Phil Noel
Wow I missed this. Glad to see some of us are still alive. Man everything here has slowed to a bloody crawl and it's all stuck in some kind of Black Abyss.
I bought two Hawk Pros recently and I have only built one. The other sits in a box waiting for some more room to be made within the house. I have forgotten how long it really takes to put in the electronics and set it up correctly.
-Wayne
Fly it like you stole it! |
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