Trex 700N tail high pitch vibes during funnel or similar

[mqowen]

My regular flying buddy has trex 700N. Awesome heli overall. What seems to occur often is the development of high pitch tail vibes during a inverted tail down funnel or similar inverted tail in hurricane. It usually can get corrected by maintenance on the boom supports and other things related to tail tightness.

As a matter of fact this exact thing happens on the 700e as well.

Seems to be often that this occurs. I fly a TSA 700N and I have never had this occur.

Is this a problem with other Trex owners? And are there some tricks or upgrades that might be done to help minimize this situation?

[marc8090]

You already mentioned the problem. The ends of the stock tail boom supports get loose. Easiest fix is to install KDE boom supports.

[mqowen]

Originally Posted by marc8090

You already mentioned the problem. The ends of the stock tail boom supports get loose. Easiest fix is to install KDE boom supports.

I have to say those look pretty good.

[mqowen]

Originally Posted by marc8090

You already mentioned the problem. The ends of the stock tail boom supports get loose. Easiest fix is to install KDE boom supports.

I have to say those look pretty good.

[Rob43]

Many use KDE boom supports on a variety of 700's out there. I have them on my 700N as well. I'd also suggest KDE's boom clamp. It has a polymer bushing made into the clamp to grasp the boom without overstressing the boom tube. It includes a pair of special fasteners which are threaded into interference threads and permanently thread locked into the clamp. The supports are then secured with M4 nylock nuts (included). Excellent!

LINK

[mqowen]

Originally Posted by Rob43

Many use KDE boom supports on a variety of 700's out there. I have them on my 700N as well. I'd also suggest KDE's boom clamp. It has a polymer bushing made into the clamp to grasp the boom without overstressing the boom tube. It includes a pair of special fasteners which are threaded into interference threads and permanently thread locked into the clamp. The supports are then secured with M4 nylock nuts (included). Excellent!

LINK

Thanks, sounds like good advice.

[DCflyer]

have that setup on mine as well. No chance of it coming loose and helps reduce vibs with the polymer bushing inside the boom clamp.

BTW, those special threaded bolts/locknuts have to be bought separate or you can use the stock bolts if you wish:
http://www.kdedirect.com/collections...cts/at700-tbma

If you can still find the KDE metal bracket that attaches the boom supports to the actual airframe side, it really is a complete system. Uses huge locknuts there as well.

[mqowen]

Originally Posted by DCflyer

have that setup on mine as well. No chance of it coming loose and helps reduce vibs with the polymer bushing inside the boom clamp.

BTW, those special threaded bolts/locknuts have to be bought separate or you can use the stock bolts if you wish:
http://www.kdedirect.com/collections...cts/at700-tbma

If you can still find the KDE metal bracket that attaches the boom supports to the actual airframe side, it really is a complete system. Uses huge locknuts there as well.

I sent this information to my Trex flying buddy.

[Drivelayer]

While KDE is great you can also pin the end of the boom support by drilling a 1/8" hole through the end and carbon fiber rod then gluing in a small length of 1/8" carbon rod. That will prevent it from working loose, and costs pennies with no wait for shipping.

["SUPER-STROKER"]

Yessir. I drill right into the "I" where Align is raised.

[Rob43]

An update from my KDE boom clamp...a couple of months ago, mine lost the polymer bushing. Patrick indicated he'd never had that happen in all their testing. Leave that to me, I guess. I re-installed the stock tail clamp for the time being, and wrapped the boom with electrical tape to provide some grip and cushion. It's been fine. For the KDE clamp, since all was fine except the bushing, I made my own. I used some metal-reinforced gasket material I had on-hand, and CA'd it to the clamp halves. Then, a thin additional lining of heat shrink tube cut in half, likewise CA'd in place. I'll swap it over winter. But, my stock clamp bolts have been very secure. If I had the stock bushing in-hand, I'd remove it, and use JB Weld to secure it. CA was used, and it simply took too much telescoping action from the side to side loading, I guess.