REFLECTOR: RG Questions

Tue Apr 10 13:59:20 CDT 2007

Scott, John, Dave,

I fly a standard elite RG.  Just like John's plane.  I only have about 65-70 landings but I hasten to add that maybe 5 were are ones that I would witnesses to observe.  That said,  my gear bolts are still straight, my gear legs are straight and nothing is loose.  I know that Scott and John were not the original builders.  I built my plane and the gear was installed according to plans using the original kit supplied hardware.  5/8" gear leg bushing, 1/2" AN bolt (grade 5) and Nyloc nuts.  If you haven't already done it, I would recommend you download the manual section on main gear installation and make sure that that's exactly what you've got.

Dave, you have something going on that I think might be kind of scary.  If that Nyloc nut got hot enough to melt, the aluminum bushing underneath it is also getting very hot.  Hot enough  to soften the epoxy that is supposed to hold it in place.  You need to install a heat shield to protect that area.  You also mention that your gear leg was loose and the nut was ready to fall off.  The purpose of the nut is to keep the bolt from falling out, not to remove slop in the gear leg support.  If the bolt is still in both bushings, the gear should function normally.

I wish you all well and hope this is of some help.

Larry Coen
N136LC
SE/RG Franklin IVO

P.S.: Scott, the nose bleed is fixed.

  ----- Original Message ----- 
  From: Scott Derrick 
  To: Velocity Aircraft Owners and Builders list 
  Sent: Friday, April 06, 2007 2:03 PM
  Subject: Re: REFLECTOR: RG Questions

  John,

  There isn't any good news with a bent main gear bolt.  Been that and done there. 

  The problem is exacerbated by the thin sleeve that is used in the gear leg. It has about a 1/16 inch thick walls and when the bolt bends the sleeve bends also.  I've replaced the sleeves twice.  By turning the bolt you are now forcing the bolt to turn in the bushing when you retract or extend the gear. I'd put some oil or grease on that bushing now. 

  I think it would be a miracle( they do happen) that by placing the bolt in an approximate 180 degree position that everything will straighten out. More likely it will just bend in another spot.  Spaghetti Bolt!  As long as your gear retracts fine without binding anywhere you can probably ignore it for now.  You will end up pounding it out at some point.

  I have just finished( well I do have to paint them) adding carbon wraps and embedded brake line tubes to my main gear.  My bolts were just slightly bent when I removed the legs. Knowing they had bent bothered me the whole time I was working on the legs. After finishing the first coat of primer I tried to insert "new" bolts and of course the sleeves were bent.  What a drag....  

  So I decided to try a fix, I removed the bent sleeves(I've had practice), and replaced them with a new size.  1/2 inside diameter(My V is a Std and has 1/2 bolts) with a 7/8 outside diameter  4130 steel tube.  I had to ream out the hole in the gear legs to 7/8 and epoxy the new sleeves in.  Maybe I went overboard on the thickness, it added 1/2 lb. to the plane but I am really sick if these bolts bending.  My theory is the bolts, at least my bolts, always bend in the middle, because the sleeve is so thin if provides little if any support and the leg is so flexible it doesn't provide any support to the bolt. The 7 inch span through the leg is just too long and the bolt bends. By using a thicker sleeve that will not bend I'm hoping the bolt won't bend.  Or at least together they won't bend.

  Its an experiment which is what our planes are all about, since I'm going to raise my gross weight I think I need a better main gear mounting system, we'll see how it fairs this summer.

  Scott

  John Dibble wrote: 
Dave,
Thanks.  That's a very good observation.  I have the Franklin engine and the closest exhaust is 12" away.  I don't think heat is an issue for me.  I was able to tighten both nuts.  I'm thinking that the force that bent the bolt also stretched the bolt and or compressed the firewall and bulkhead making it loose.  I don't want to reverse the bolts right now because they're slightly bent.  I'm hoping that by turning them 180* they will eventually bend back straight and be easier to remove.

John

davedent at comcast.net wrote:

  John if your bolt is bent there is a good chance that the fiber lock nut has lost its torque.  Check this to be sure.  Also if you have the fiber nut that Velocity issued double check this as well.  The bolt is a grade eight but the nut is not.  Also if you install the bolt the way the plans tell you with it being front to back with the nut in the engine compartment change it out.  There should be no fiber lock nuts in the engine compartment. This is wrong.  I have lost four right hand gears because of looseness of that nut before I realized what had happen and what was going on.

Before the first three I had to cut the bolts out because of so much bending of the bolts.  So I didn't realize that the nut was loosening up.  The last time there wasn't that much damage so I just checked to see if the bolt was bent and if I was going to have a big problem in getting the gear out.  When I went to check with the plane on jacks I found the gear real loose in the mount and the bolt just spun.  So I took the cowl off and found the nut was about to fall off.  I was able to just spin it off.  The fiber portion had melted and became useless.  The right hand gear nut is just four inches from my exhaust on that side.  That's why I never had problems with the left gear.  It's close to 12 inches from the exhaust.  DAAAAA/ I should have thought of this a long time ago.  I couldn't believe I was the only one having this problem.

So now I have the bolts facing forward with drilled grade eight bolts and castle nuts.  When you don't have bearing in a pivot point then you must use drilled bolts with cotter pins.  Because the first thing that will turn when the bolt is bent is the nut coming off.  I should have thought of all this but I am one of the guys that always says the plans are correct.  Boy I'm I wrong on this one.  I lost three gears before realizing the problem.  Don't let it happen to you. Check it and if you can get the fiber lock nuts out of the system and out of the engine compartment.
Dave

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