cvause

I'm upgrading the main gear on my LT-40 from the wire gear to a Dubro fiberglass main gear. I've epoxied hardwood blocks in the bottom of the fuse to account for the wider mounting footprint, but now I'm debating whether to use wood screws into the wood blocks or drill out and mount with blind nuts and bolts.

Any suggestions?

Thanks,

Schultz

My Feedback: (1)

My preference is to use blind nuts and bolts with an added plywood reinforcement inside of the fuselage. This method allows removal and reinstallation of the landing gear for cleaning, straightening the gear and any other reason that may come up without wearing out the screw holes as might be the case with wood screws. The disadvantage, as I have experienced, is that the bolts and nuts will pull out the bottom of the fuselage on an especially hard landing where the wood screws may just pull out of their holes without damaging the plane. The choice is yours.

Schultz

Campgems

Neither. drill and tap 10-24 threads and use nylon screws. That size will take most hard landings OK, but if you snag a wheel will shear off and leave the plane intact. I use that gear on most of my planes and it can't be beat in my mind. On my first 4*60, I re-drilled the LG to fit the bolt patern of the stock gear and used the blind nuts and steel screws in the kit. The first time I really hit hard, the landing gear seperated from the plane, but the whole landing gear mount was still attached to it. After that rebuild, I used the nylon bolts. I've sheard them a few times and no damage to the plane. Our field is infested with ground squirels and if you run off the runway and drop a wheel in one of the holes, something has to give. It is better that a lot of the enegery is used shearing off the nylon bolts. It sames damage to the plane that way.

I get the screws at the local ACE hardware store in their bulk screws bins. 10-24 x 3/4" pan head screws. Get a dozen while you are at it. Four to bolt in on and four for the first seperation, four more in case you are having one of those days.

In case you haven't use them before, you drill with a tap drill, the same as for metal work. Thread the holes then drip some CA in on the threads. Make sure you pack the inside of the plane with paper towel to catch any CA that drips through. Let it dry for a half hour or so and then run the tap in a second time, picking up the first threads. This cleans up the threads and gives a very hard thread in the wood.

Don

mmattockx

+1 on this. I would use 1/4-20 nylon screws instead of the #10's but that is it. The nylon bolts will hold through most anything up to a big hit, then they pop the head off and let the gear go without ripping the mounting plate and fuse apart. 5 minutes with a pocket knife to dig out the sheared bolts and you are back flying.

Mark

rwright142

+2

DavidAgar

My Feedback: (108)

1/4 by 20 nylon bolts are the way to go. They have saved me plenty of airplane repair time. Good Luck, Dave

flygilmore

True that the 1/4 20 nylons help at times but it really depends on the plane. You have to remember that when all that alum and wheels go flying off, they have to go somewhere. I have seen many a plane have the horizontal stab removed or the underside of the wing damaged from the gear giving way-sometimes a very large amount of damage for a simple incident that required a very involved repair.

cvause

Thanks for the nylon bolt suggestion. I'm headed in that direction, after I stop by Ace Hardware today.

vicman

My Feedback: (10)

Any reason why you are changing gear?
The wire is much more forgiving than solid.

dixielandsbigal

I like Nylon bolts too. however. On my second UCD .46 i Fiberglassed the landing grear area. Now that is STRONG! The UCD is known for week landing gears so I glassed it right away.. I also did it for a friend (on a UCD) who is a fairly new pilot, he actually bent the gear and it didnt budge from the fusalage. The nylon bolt is an easy out if your not comfortable glassing.

dr_wogz

My Feedback: (3)

Ditto for nylon 1/4-20 bolts..

A bit of thin CA in the tapped threads, then re-tap [chase] the holes...

Take the bolts, cut them to length, then run them in a pencil sharpener, to give them a nice chamfered edge.

huggins

I belong to the blind nut and steel screws camp, provided the mounting area is of adequate strength. If it tears out....call it a crash rather than a bad landing. I have seen this issue argued both ways. There is no consensus.

Mike

Gray Beard

My Feedback: (-1)

I use both steel and fiber on my stuff, depends on the plane mostly. I had A 1/4 scale Extra with 1/4 20 and it made no difference if you greesed the landing or had A bouncer, the fiber screws broke off at the heads. I went to 4-40 stainless and never had another problem with that plane. When I go with metal I use both blind nuts and brass inserts.
The trick to removing broken nylon bolts is an old small screw driver and A small hand tourch, like the crack heads love so much. I heat the tip of the driver cherry red and push it into the bolt/screw as deep as I can, let it cool and unscrew it. Hasn't failed me yet and i use the tourch to do A lot of soldering too. Buy A cheap one at Harbor Freight and keep it in your flight box, it has helped out A lot more guys then myself!!

Azcat59

I use a third method......#4 sheet metal type screws. Drill the holes reasonably tight in the hardwood or plywood base. They never tend to vibrate loose, as the blind nut/bolt system may allow, and in a hard landing they may pull out of the plate, leaving the basic structure intact. Then you drill them slightly larger and use #6 screws. I just finished my 124th RC airplane (no ARFs) and this system has worked well, and most of my friends use it as well.

Clair

tonyL1

My Feedback: (1)

another method although oldschool, is to attach the landing gear is to use
2 dowels and rubber bands, in a way some trainers use for wing like,
I had a kit that used this method ( Midwest 1970's Das Little Stik)
it took a extemely hard hit ( flew low and fast, ground creeped up lol)
rubber bands popped, no damage to fus, if it would have been Blind nuts whatever
the bottom of fus would have been totaled, only prob with it, is it looks ugly lol
then again i had em on a ugly stik lol