TRex 500 Problem After Hitting Sign

Doug Sisco · 07-20-2012, 08:30 AM

I crashed my Trex 500 (everything standard) into a sign (oops!). It was a very slow crash and didn't seem to do much damage. I replaced the main gear, a skid, and the main blades. Amazingly, everything else seems in good shape.

But now the tracking on one blade alternates between perfect and way out of line. It seems to have good alignment when the pitch is up but goes-out when pitch is at hover.

The swashplate movement is smooth and none of the surfaces 'stick'. Nothing looks bent or feels loose; there is no slop.

Any ideas would be appreciated.. I'm getting itchy to fly again.

GT86 · 07-20-2012, 09:05 AM

Check your feathering shaft. A crash that takes out the blades is almost guaranteed to bend at least the feathering shaft, and likely the main as well.

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scoti333 · 07-20-2012, 09:18 AM

yes, your feathering shaft, aka spindle, is almost definitely bent. Id bet money on it. A way to tell without taking everything apart is: Take the blades off and put a hex driver in the bolt of one side of the spindle. Turn said driver in a steady motion and watch if the opposite blade grip goes up and down. It might not be bent enough to see tho, so grab it with your hand and feel if its moving. Id replace it anyway without even looking at it. Check your main shaft while your at it too.

fastflyer20 · 07-20-2012, 10:07 AM

Any time a heli crashes, no matter how "lightly", you should check everything mentioned above plus bearings, including the main shaft bearings and grip bearings. Even a minor crash on a 500 usually requires main bearings.

Mike2112 · 07-20-2012, 05:55 PM

Quote:

Originally Posted by fastflyer20

Any time a heli crashes, no matter how "lightly", you should check everything mentioned above plus bearings, including the main shaft bearings and grip bearings. Even a minor crash on a 500 usually requires main bearings.

Hell yeah
I always change the spindle and bolts after any crash. Never mind tracking problems, what about if the blades eject due to a small bend or crack in the bolt and end up in a human throat?

Also, I've noticed bad bearings in the grips and/or deformed dampers have done that to some of my helis.

I would swap the spindle and main shaft and retest it.

pxpep · 07-21-2012, 01:22 AM

Quote:

Originally Posted by scoti333

A way to tell without taking everything apart is: Take the blades off and put a hex driver in the bolt of one side of the spindle. Turn said driver in a steady motion and watch if the opposite blade grip goes up and down.

Leave the opposite blade on when doing this and any movement will be amplified and very visible at the end of the blade when turning the spindle.

If its a flybarred heli also carefully check the mixing arms for any play.

Doug Sisco · 07-22-2012, 08:15 PM

Pxpep, Mike2112, fastflyer20, scoti333, GT86 - Wow, you guys are great! I really appreciate all the replies, and I will definitely check my feathering shaft and main shaft (I have spares of both). It's really nice to know you pros are willing to help with strange problems like this.

This heli (Align TRex 500) is a dream- I just can believe how little damage was done after hitting a sign. I replaced the main gear and blades with cheap aftermarket parts. I made some pitch adjustments and I'm back flying again. There's no noticeable vibration and the heli is flying quite well. Of course I'm not doing any inverted flight but everything seems to work well.

I hit the same sign about a year-and-a-half ago with a smaller heli (I think this sign is out to get me) and it practically destroyed it. Everything was either bent or broken and I used it for parts

The only weird thing with the TRex is that when I adjust the pitch too low the one blade tracks much lower than the other. Hopefully a new main or feathering shaft will fix this.

07-20-2012, 08:30 AM	#1
Doug Sisco Registered Users Join Date: May 2012 Location: US, Pa	TRex 500 Problem After Hitting Sign I crashed my Trex 500 (everything standard) into a sign (oops!). It was a very slow crash and didn't seem to do much damage. I replaced the main gear, a skid, and the main blades. Amazingly, everything else seems in good shape. But now the tracking on one blade alternates between perfect and way out of line. It seems to have good alignment when the pitch is up but goes-out when pitch is at hover. The swashplate movement is smooth and none of the surfaces 'stick'. Nothing looks bent or feels loose; there is no slop. Any ideas would be appreciated.. I'm getting itchy to fly again.

07-20-2012, 09:18 AM	#3
scoti333 Registered Users Join Date: Apr 2010 Location: austin,TX	yes, your feathering shaft, aka spindle, is almost definitely bent. Id bet money on it. A way to tell without taking everything apart is: Take the blades off and put a hex driver in the bolt of one side of the spindle. Turn said driver in a steady motion and watch if the opposite blade grip goes up and down. It might not be bent enough to see tho, so grab it with your hand and feel if its moving. Id replace it anyway without even looking at it. Check your main shaft while your at it too. __________________ -Goblin 700: Crashed but re-building, still needing electronics To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. -Goblin 630: CC Ice 120HV, vBar

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07-20-2012, 09:05 AM	#2
GT86 Registered Users Join Date: Mar 2010 Location: Phoenix, AZ USA	Check your feathering shaft. A crash that takes out the blades is almost guaranteed to bend at least the feathering shaft, and likely the main as well. Sent from my tablet via Tapatalk

07-20-2012, 10:07 AM	#4
fastflyer20 Registered Users Join Date: Nov 2008 Location: Buffalo Area	Any time a heli crashes, no matter how "lightly", you should check everything mentioned above plus bearings, including the main shaft bearings and grip bearings. Even a minor crash on a 500 usually requires main bearings.

07-22-2012, 08:15 PM	#7
Doug Sisco Registered Users Thread Starter Join Date: May 2012 Location: US, Pa	Pxpep, Mike2112, fastflyer20, scoti333, GT86 - Wow, you guys are great! I really appreciate all the replies, and I will definitely check my feathering shaft and main shaft (I have spares of both). It's really nice to know you pros are willing to help with strange problems like this. This heli (Align TRex 500) is a dream- I just can believe how little damage was done after hitting a sign. I replaced the main gear and blades with cheap aftermarket parts. I made some pitch adjustments and I'm back flying again. There's no noticeable vibration and the heli is flying quite well. Of course I'm not doing any inverted flight but everything seems to work well. I hit the same sign about a year-and-a-half ago with a smaller heli (I think this sign is out to get me) and it practically destroyed it. Everything was either bent or broken and I used it for parts The only weird thing with the TRex is that when I adjust the pitch too low the one blade tracks much lower than the other. Hopefully a new main or feathering shaft will fix this.