mxaexm

I have to attach the landing gear for my Telemaster 40. Could you tell me if I should use 4 nylon bolts or the metal bolts will be ok?

Allfat

My Feedback: (1)

I have a 4*40 and I used the stock metal bolts.  After tearing out the landing gear attachment block about 5 times on less than ideal landings, I am not going to switch over to nylon bolts to see if that saves me time with not having to replace the landing gear block, just replace a couple of bolts.  This experience has me thinking that any plane in the future that I own will have the landing gear on with nylon bolts as a weak point in the system.

mclina

I always use three #6 bolts with blind nuts in the landing gear block, and reinforce the landing gear block with tri-stock. I have occasionally had a landing gear block rip out on a bad landing, but from what I have seen, the nylon bolts tend to break too easily, and the gear ends up going through the wing.

One tip I have gotten from the guys who use the nylon bolts is to sandwich a thin sheet of rubber between the landing gear and the fuse. This helps to keep a little bit of the nylon bolt sticking out for you to grab onto after they snap off.

Good luck.

mxaexm

I'm afraid that the nylon bolts might be too weak...

HighPlains

My Feedback: (1)

It really depends on the size of the nylon bolts (1/4-20 or 10-24?), the weight of the plane, field conditons and how skilled at landing you are. The mat under the gear is an interesting idea, but you can usually get the broken stud out with a flat blade screw driver heated up to make a slot without too much problem.

mclina

If you do use nylon bolts,they cannotbe the same size as the metal bolts. If this is an ARF that has blind nuts installed for #6 bolts, you cannot just use #6 nylon bolts, you have to use 1/4" nylon bolts, so you need to replace the blind nuts with 1/4" or drill and tap 1/4"-20 holes.

Good luck

opjose

It boils down to what you want to repair after a hard landing.

If you re-inforce the fuse where the landing gear join it, the gear will be stronger, but you'll end up doing more damage to the airframe during a hard landing.

If you put in nylon bolts, the gear will break more easily, but the fuse will tend to hold up better, however the gear will tend to rip through the wings if you use wheel pants.

Remove the wheel pants and you get less wing damage, or very easily repaired wing damage.


I've seen many cases where people have complained of "weak" aluminum or metal landing gear, that I find "just right".

The gear deforms upon a hard landing, saving me from time consuming repairs.

GaryHarris

I just beefed up my landing gear on my LT-40 with this.

http://www3.towerhobbies.com/cgi-bin...?&I=LXHBP8&P=0

I used 4  #8x1" wood screws at the 4 corners into the landing gear block and 1 #6x3/4" in the center of the leading egde.

CGRetired

My Feedback: (1)

This can be a tough decision.  I've had both and had both the mounting torn out as well as had nylon bolts get sheared. 

The problem with nylon is that if you do hit hard, they might shear on their own.  But again, if the mounting itself is of poor design, as some owners have complained about, a hard hit will also tear it out. 

I guess it comes down to how well the mounting blocks are installed and if you want that shearing capabilities.  The nylons will shear if hit hard, that's a given. 

CGr.

mxaexm

Telemaster 40 looks like a solid design and I will also add some ply inside the fuselage to make the landing gear mount area much stronger....I was thinking of using the nylon bolts but now I'm thinking that the metal bolts should be fine.

JustPlaneSweet

I usually use one size larger nylon bolts to hold on the landing gear.  If the kit has #6 steel then I use #8 nylon.  The nylon is plenty strong.  If you have a low wing with wheel pants on the gear (those also held on with nylon bolts) you have a different problem because the gear will release and the wheel pants will punch holes in the bottom of your wing.  I added a fiberglass reinforcement patch on the inside of my Somethin Extra wing to resist the punching.  Works great.

I carry extra nylon screws in my flight box and ripping off the gear is a non-issue.

Stan

Campgems

I'll add my 2 cents worth, I would use nylon bolts. Four 10-24 (note not the 10-32s) will hold up very well on a plane like the 4*60. The only time I sheard them was when I landed off the runway and dropped a wheel in a goppher hole, Or hit the edge of the asphalt flag on the far side of your runway. Really had landings on the runway seldom caused a problem.

My first 4*60 experienced a complete ripout of lthe langing gear mount when I touched down prior to the runway. That is the only time I punched holes in the wing from the gear comming loose. When I repaired it, I re-enforced the block, running stringers all the way to the fire wall. I pulled the blind nuts out and drilled and tapped the block for a four bolt pattern of the Dubro Composit landing gear and used 10-24 threads directliy in the wood. I used thin CA on the threads and then re-tapped the holes. On this 4*60 as well as the next and two other 40 size plans with the same landing gear and attachment method, I probably sheared the landing gear loose another dozen times. A broken prop and a little time fishing the screws out of the landing gear mount and I was back in business. I never again punched a hole through the wing. I currently have two other planes with the same gear/setup, on has yet to fly and the other has been rebuilt twice now, but the landing gear only broke off on the second crash and it was into a bush. No damage to the fuselage.

Don

mscic-RCU

My Feedback: (6)

I have used nylon bolts for years.  I usually use 1/4-20, two of them work fine.

TideFlyer

I used nylon bolts on a Pulse XT 40 and came away a believer. Better to shear off a bolt head than rip out the gear, IMO.

mxaexm

Thanks guys,

I will get 1/4 20 nylon bolts (4 bolts).

It the bolts will break off too easily, then I can always get the metal bolts.....vs..getting the metal bolts and then repairing the fuselage...If you know what I mean...

HighPlains

My Feedback: (1)

4 bolts at 1/4-20 is too strong to shear away.  4 bolts at 10-24 would be better.

mxaexm

Will do! thx

bkdavy

My Feedback: (1)

Build your plane to take the stress of landing.  If you have to beef up the landing gear blocks, then beef up the landing gear blocks.  Many planes today are built with insufficient support to transfer the stress of landing to the rest of the airframe.  Designing you plane to make the landing gear shear off just means you'll be replacing lots of bolts, and probably lots of props.  Using the proper structure to transfer the stress is easy, and doesn't add significant weight to the plane.  The small weight addition is well worth the performance inprovement.  Having to use nylon bolts so they shear off before the wood breaks is just a bandaid for a poor landing gear design. 

Brad

MetallicaJunkie

If you are a beginner, nylonf 1/4-20 bolts are the way to go, they should break before the fuselage does, the metal ones wont. They supply nylon bolts for a reason.

tony0707

hiI use large screws into 5ply plywood-  with  1/2 inch  1/4 round hardwood -purchased at the lumber yardat the inside corners of all my fuses (be sure the bolt is into wood its whole length )-i have never had a gear come off my plane in 20 years  -from just landings-i use metal bolts to hold my wings  on and my gear on  -i feel it is going to break off -or not come off at all-   i do not trust the nylon bolt thing  -too much chance they wiil give out when least expected for me-(from fatique )  just don't crash -the set up i explained will not come off from regular landing -even if a lot bouncy   but do remember to tighten the gear down ever 10 flights or so -they do loosen up some from use-    if you loose your gear   -i hate that   -embaresing and the plane is done for the day      -i try to avoid done for the day things

Campgems

I've got to point out something about nylon bolts. You can't tighten them like a steel bolt. They stretch with little torque. If you try to tighten them like a steel bolt, the will break on the first firm landing becasue youhave prestressed them almost to the breaking point by over tightening them.

Screw the bolt/screw down and as soon as you feel some resistance from the bolt being fully seated, just go another 1/2 turn with the screwdriver or wrench. That puts enough stretch in the bolt to keep it from unscrewing, but still leaves about 99% of it's tensle strength. A rough landing will stretch the bolts a bit and then the spring back, no harm done. If they are pre=stressed to almost the point of breaking, the rough landing will shear them all in a snap.

An easy hand tightening them gives you the best strength and the most elasticity to take up the shock of a rough landing.

If you want to test this, try to tighten a 6-32 steel bolt untill you pop the head off. Now try the same with a 10-24 nylon bolt. You will be susprised how much easier it is to pop the head off the nylon bolt, but you will also be susprised on how many turns it takes after the bolt is tight on the nylon compaired to the steel bolt. This elasticity helps if you don't over tighten the bolts.

Don

OzMo

My Feedback: (3)

CAMPGEMSNAILEDIT! also be sure your blind or "T"nuts fit the threads well. not to loose or to tight.
There does seem to be a lot of variation in these. Take a 1/4 20 plasticbolt with you to the hardware store and test 'em. If you find a brand or batch that work buy a stock of 'em.

Campgems

Do you remember from the way back when, when the NEWnylon props came out. You had to boil them in water to condition them or they would fly apart on the engine. And if they survived a while boil them again. Maybe we should boil our nylon screws in water prior to using them.

Don

mikenlapaz

Are you saying  you are suppose to boil just the props and bolts?  My planes have been rather heavy after I remove them from the bathtub. Humm

MetallicaJunkie

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