Ever bend a boom in flight?

BaconRaygun · 07-09-2012, 08:48 PM

Strangest thing ever... Sunday I was at the field, flying my Fusion 50. First flight, all good, just smooth sport flying with low HS (2035). On the second flight I was doing speed passes and hard knife edge turns when suddenly a massive vibration developed, I quickly landed and went over the heli only to find nothing... I was thinking maybe a bearing on my TT broke free.

Today I pulled the TT and the bearings are fine... so as a last resort I pulled the boom. What do you know, its bowed!

No tail strikes or anything, I did recently break a set of skids (which I'm convinced were defective) doing autos, but I checked the boom afterwards and it was fine. This was the second flight after that check.

This is me right now >

Anybody ever bend a boom in flight?

SamCassidy · 07-09-2012, 09:04 PM

that is WEIRDDDD dude!

Cailid · 07-09-2012, 09:06 PM

The autos could have weakened the boom where you couldn't see it.

Maypole · 07-09-2012, 10:46 PM

Quote:

Originally Posted by Cailid

The autos could have weakened the boom where you couldn't see it.

Yeah, makes sense. If you were coming down hard enough to toast some skids, even defective ones, that could easily be enough force to bow the boom.

Also, you might have missed it when checking it after the broken skid. I had one slightly bowed on my 500 in a light crash that I couldn't tell was out of whack until I removed it and rolled it across a glass table top.

Commodore8888 · 07-09-2012, 11:18 PM

I could see it happening if you either had some metal fatigue going on or maybe a brief moment of serious force, especially if somehow your boom braces got a little loose.

I have been first hand witness to a carbon fiber overlaid boom cracking up in flight though. Whole tail assembly was caught by the mains at the tail blades after coming loose and jettisoned. The heli was being flown by a good pilot though who got it down with only a few nicks in the canopy.

Very common to get stress fractures at the right angles where the support brackets and tail cases start on the boom. If you have CF on a larger bird, check that area.

Slyster · 07-09-2012, 11:23 PM

last weekend a friends 700 boom snapped off at the boom support clamp.. the whole tail just flew away. It was amazing because even though he lost the the foot of boom and tail rotor.. he landed it without any damage! He thinks he had the clamp too tight. Now he is running a CF boom

im4711 · 07-10-2012, 03:56 AM

So you broke some skids (sure manufacturing failure...... since it was a silk smooth auto landing and they just vaporized.

).
I think you might have hit the ground are and possibly damaged or at least partial damaged the tail boom. Sometimes Did you really pull it and check if it was straight? Should be hard to have a tail boom bent in mid flight with no external force. Great story but I hardly believe it. Something hit it.

BaconRaygun · 07-10-2012, 09:03 AM

To clarify... I pulled the boom after I broke the skids, and rolled it on a granite countertop.

The skids... Yes, I broke them, yes they were defective...they didn’t vaporize, one strut broke at the 'clamp'.
im4711, you own a Fusion right? You know how the clamp mechanism works on the skid pipes? These were the black Velo50 skids, old ones from a friends spare parts bin... when I originally installed them, the nylock nuts pushed through the clamp mechanism before even securing the skids. I had to drill holes and use set-screws like Align skids to secure the pipes. They were brittle.

After one week and countless autos, one front strut broke, everybody at the club noted that it was not a very hard impact and that the skids must be a bad batch. After this I ordered new struts, pulled the boom and checked it, and pulled the head and checked shafts and replaced dampers. Anybody that knows me knows I'm totally anal with my helis, I check everything at the slightest indication of a potential problem... that's why I never have failures.

The boom is really soft right now, only thing I can think of is fatigue over time that did it in (its original, 450+ flights)... yeh, I did also have my boom-brace clamp on too tight.

If it wasn’t the boom... then I'm at a loss to what that massive vibration was. I checked everything and nothing is damaged other than the boom.

07-09-2012, 08:48 PM	#1
BaconRaygun Registered Users My HF Map location Join Date: May 2010 Location: Long Island, NY	Ever bend a boom in flight? Strangest thing ever... Sunday I was at the field, flying my Fusion 50. First flight, all good, just smooth sport flying with low HS (2035). On the second flight I was doing speed passes and hard knife edge turns when suddenly a massive vibration developed, I quickly landed and went over the heli only to find nothing... I was thinking maybe a bearing on my TT broke free. Today I pulled the TT and the bearings are fine... so as a last resort I pulled the boom. What do you know, its bowed! No tail strikes or anything, I did recently break a set of skids (which I'm convinced were defective) doing autos, but I checked the boom afterwards and it was fine. This was the second flight after that check. This is me right now > Anybody ever bend a boom in flight? __________________ ~Outrage~ Fusion 50 (FB) ~Compass~ Warp 360 ~Blade~ mCP X (BL) AMA# 977012 Team Boca BearingsTeam LYNX Heli Innovations The member formerly known as Vicovaludemero

07-09-2012, 09:04 PM	#2
SamCassidy Registered Users My HF Map location Join Date: Jan 2012 Location: Eastern North Carolina	that is WEIRDDDD dude! __________________ Compass Atom 550: SK540 / DS510 / KingMax 5308MDHV / Castle Talon 90 / KBDD Tail / Mavrikk 515 VST Main Blade mCpx / Nano Cpx mild BL - Skookum Field Rep - The Official Pistol Gang - Mavrikk Rep - ) :>

07-09-2012, 09:06 PM	#3
Cailid Registered Users Join Date: Feb 2009 Location: Abbotsford B.C.	The autos could have weakened the boom where you couldn't see it. __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. MCX, CX2, MSR Blade 400, 500ESP, 500CF

07-09-2012, 11:18 PM	#5
Commodore8888 Registered Users My HF Map location Join Date: Apr 2011 Location: Rockville, Maryland	I could see it happening if you either had some metal fatigue going on or maybe a brief moment of serious force, especially if somehow your boom braces got a little loose. I have been first hand witness to a carbon fiber overlaid boom cracking up in flight though. Whole tail assembly was caught by the mains at the tail blades after coming loose and jettisoned. The heli was being flown by a good pilot though who got it down with only a few nicks in the canopy. Very common to get stress fractures at the right angles where the support brackets and tail cases start on the boom. If you have CF on a larger bird, check that area. __________________ Resident Mad Scientist E5-S KDE 600XF / 600N 55HZ 450 Pro V3 / Mod 130x / mCPX BL Mike D--AwesomeRC Hobbies

07-09-2012, 11:23 PM	#6
Slyster Registered Users My HF Map location Join Date: May 2008 Location: Maplewood, MN	last weekend a friends 700 boom snapped off at the boom support clamp.. the whole tail just flew away. It was amazing because even though he lost the the foot of boom and tail rotor.. he landed it without any damage! He thinks he had the clamp too tight. Now he is running a CF boom __________________ It's not just a hobby... it's a lifestyle! Outrage Fusion & 550 / Goblin 700 / SK540 / Kontronik / DX8 / Quantum / RJX / 4010 Duo Pete Team Outrage. Last edited by Slyster; 07-10-2012 at 03:58 AM..

07-10-2012, 03:56 AM	#7
im4711 Registered Users My HF Map location Join Date: Oct 2008 Location: Cape Coral, FL, USA	So you broke some skids (sure manufacturing failure...... since it was a silk smooth auto landing and they just vaporized. ). I think you might have hit the ground are and possibly damaged or at least partial damaged the tail boom. Sometimes Did you really pull it and check if it was straight? Should be hard to have a tail boom bent in mid flight with no external force. Great story but I hardly believe it. Something hit it.

07-10-2012, 09:03 AM	#8
BaconRaygun Registered Users Thread Starter My HF Map location Join Date: May 2010 Location: Long Island, NY	To clarify... I pulled the boom after I broke the skids, and rolled it on a granite countertop. The skids... Yes, I broke them, yes they were defective...they didn’t vaporize, one strut broke at the 'clamp'. im4711, you own a Fusion right? You know how the clamp mechanism works on the skid pipes? These were the black Velo50 skids, old ones from a friends spare parts bin... when I originally installed them, the nylock nuts pushed through the clamp mechanism before even securing the skids. I had to drill holes and use set-screws like Align skids to secure the pipes. They were brittle. After one week and countless autos, one front strut broke, everybody at the club noted that it was not a very hard impact and that the skids must be a bad batch. After this I ordered new struts, pulled the boom and checked it, and pulled the head and checked shafts and replaced dampers. Anybody that knows me knows I'm totally anal with my helis, I check everything at the slightest indication of a potential problem... that's why I never have failures. The boom is really soft right now, only thing I can think of is fatigue over time that did it in (its original, 450+ flights)... yeh, I did also have my boom-brace clamp on too tight. If it wasn’t the boom... then I'm at a loss to what that massive vibration was. I checked everything and nothing is damaged other than the boom. __________________ ~Outrage~ Fusion 50 (FB) ~Compass~ Warp 360 ~Blade~ mCP X (BL) AMA# 977012 Team Boca BearingsTeam LYNX Heli Innovations The member formerly known as Vicovaludemero

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode