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Thunder Tiger Raptors 30-90 - Imperio > RAPTOR 50 Boom strike due to vibration in hover
 
 
RaptorMan23
Senior Heliman
Location: Sioux City, IA

I was out earlier with my raptor 50 v2 for just another normal day of flying around. I spooled up and got in to a hover and it began vibrating and shaking severely so I droped the collective to get it on the ground but it was to late, my blades struck the boom, flybar was very badly bent and I striped the gears in my one of my servos. Not an expensive fix but whats goin on?? This was only my 15th or so flight with it and I was stil dialing it in so I did have training gear on it while I set it up, but I dont think that the oscillation from the training gear would cause a boom stike?? The helicopter was purchased here on RR and Im thinking that all of the silicone may have dried up from sitting around before I got it and maybe that is the cause? tight blades? What do you guys think??



How high does it go? How fast does it go? Huh huh huh huh???!!!!
06-16-2008 04:05 AM
 
 
meowsqueak
Senior Heliman
Location: New Zealand

Did the boom strike happen AFTER you hit the ground? If so, maybe you dropped the collective too hard and the impact caused the boom strike. That won't explain the shaking however.

Or are you saying that the boom strike happened in the air?

What head speed were you running?

One thing that comes to mind based on my own experiences - check the hole through the main blade root - is it where you think it ought to be?
06-16-2008 08:20 AM
 
 
RaptorMan23
Senior Heliman
Location: Sioux City, IA

in the air

boom strike happened in the air, blades are good. Im thinking that it was a combination of dry dampers and tight blades. Im in the process of repairing it and I will post the results toward the end of the week

How high does it go? How fast does it go? Huh huh huh huh???!!!!
06-16-2008 11:27 AM
 
 
kc8qpu
Senior Heliman
Location: Hudsonville,MI, USA

Are you main grips slopped out where the bearing fit?

Bring back the rotary phone so we don't have to press "1" to proceed to ENGLIGH.
06-16-2008 04:53 PM
 
 
trunkmunki
Senior Heliman
Location: Bangor

Boom strikes usually don't happen because the head "teters" and allows the blades to come down. Even with sloppy bearings/heads/dampers this would be nearly impossible. The strikes happen when the blade trails in the grip (or leads if the head stops/slows quickly with a very loose blade) and the pitch of the grip causes the now 90 degree blade to point at the boom. For it to happen in the air, there would have to be some catastrophic failure/bent shaft/siezure of the driveline. I would think loose blades would be more prone than tight blades.
06-16-2008 05:01 PM
 
 
DMehalko(DM)
Senior Heliman
Location: Colorado

I agree, i dont see how it could happen in a hover, like said above, if the blades were too loose and the collective was dropped fast on the ground it could easily happen

Trex450se, Trex600CF, HyperRaptor 90 3d
06-16-2008 05:05 PM
 
 
jschenck
Elite Veteran
Location: La Vista, NE.

Did a link pop off? this might explain the sudden shakes and boom strike. I would suspect something came loose.

...yep...
06-16-2008 08:08 PM
 
 
trunkmunki
Senior Heliman
Location: Bangor

Agreed, if something let go that could explain a lot.
06-16-2008 08:27 PM
 
 
RaptorMan23
Senior Heliman
Location: Sioux City, IA

that is what has me puzzled

Nothing came off at all. I have absolutly no idea why I had a boom strike. It wasnt a little one either, it bent my boom pretty good. My pitch is -3 to +8 so I dont have to much pitch

How high does it go? How fast does it go? Huh huh huh huh???!!!!
06-17-2008 04:17 AM
 
 
TachyonDriver
Veteran
Location: Chipping, Lancs, UK

Quote 
but I dont think that the oscillation from the training gear would cause a boom strike

I didn't wait around long enough to see if it was possible:

When I first popped my Raptor into a hover with training gear fitted,the vibration/oscillation was so bad that I landed it within a few seconds. Bear in mind that I had seen this raptor set up and flown outside my LHS where I bought it. Removed the training gear and never looked back.

Tach.

Little Spinning Bundle of Joy®
06-17-2008 01:34 PM
 
 
TooBizzy
Senior Heliman
Location: Georgetown, Ohio USA

I had the exact same experience the first time I tried to hover my R30. I mounted the training gear with the big orange balls. When it lifted off, it shook so hard it broke the dowel rods on the training gear. I can see how you can have a boom strike if this happens.

Took the training gear off and all was good. No more shake. Try hovering without the gear...Like TachyonDriver said, you'll never look back!

P-Gasser Se, Raptor 50 Se Hyper, Raptor 30v2, Trex450se, 3dx450...
06-17-2008 04:47 PM
 
 
JuanRodriguez
Elite Veteran
Location: Rochester, New York

Quote 
so I droped the collective to get it on the ground but it was to late, my blades struck the boom

Things happen very quickly when you panic...... my guess is that the heli hit the ground and then the boom strike took place as a result of a <<less than soft>> landing and possibly a touch of back cyclic in the mix.....
06-17-2008 06:51 PM
 
 
RaptorMan23
Senior Heliman
Location: Sioux City, IA

nope

boom strike happened in the air

How high does it go? How fast does it go? Huh huh huh huh???!!!!
06-23-2008 03:52 AM
 
 
spog
Senior Heliman
Location: Ontario, Canada

Quote 
Even with sloppy bearings/heads/dampers this would be nearly impossible.
I disagree.
I didn't last 5 minutes with new blue(soft) dampers in my raptor until I had a boom strike. Twice now I have clipped off the end of my horizontal fin when the red(hard) dampers got loose.
sloppy head + stick banging = boom strike
06-23-2008 04:51 AM
 
 
Dood
Elite Veteran
Location: America's Dairyland

Quote 
I dont think that the oscillation from the training gear would cause a boom stike??

The training gear MIGHT be the culprit.

I've seen low freq vibrations show in training gear, and once they start vibrating, the vibration keeps compounding due to the non rigidity of training gear.


Once that low freq starts and compounds, it can bend your spindle (seen it first hand) and things keep getting worse, and worse, and worse, and worse...

Then before you know it, you have yourself a serious problem.

you'll need to first figure out where your vibes came from.
Could have been an imbalance, too low of a head speed, worn dampers, whatever.

"El Dooderino" if you're not into the whole brevity thing.
06-23-2008 05:02 AM
HOMEPAGE  
 
 
RaptorMan23
Senior Heliman
Location: Sioux City, IA

good news

I took the raptor up yesterday and put about a half gallon through her, wow what a difference witthout that training gear, flies like a sweetheart now. I should have never put the training gear on but I was nervous about trimming it without it on

How high does it go? How fast does it go? Huh huh huh huh???!!!!
06-23-2008 09:37 AM
 
 
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Thunder Tiger Raptors 30-90 - Imperio > RAPTOR 50 Boom strike due to vibration in hover
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