trpastor

Hey guys... I have a plane that is just tooo low to the ground. I can add a bigger set of wheels, but that will only raise me about 1/4". I think if I bend the gear a bit too it would get me 1/2-3/4 more off which would be good. Right now it's about 1 1/4" off the ground. That would give me a 2" clearance.

Can I heat them and bend them or is there nothing I can do with carbon fiber?

carlosponti

My Feedback: (1)

no you cannot heat and bend carbon fiber parts. all carbon fiber is carbon weave penetrated with epoxy. think of it as fiberglass essentially ( carbon weave is stronger of course). the only way to get more ground clearance is to buy another set of landing gear to get up higher.

crossman

Could you put a ply spacer between the gear and the fuselage?

Crash Campbell

Hi,

In my experience the advice that you can't heat and bend CF is correct. Have you considered going to a three blade prop? I have had to do this with a couple of my models fitted with retracts to obtain sufficent ground clearance.

Cheers,

Colin

sensei

The truth is, if it is an epoxy, then it is a thermal set, and it will be re-formable with enough heat applied to the gear leg, both sides at the same time.

Bob

MetallicaJunkie

id be scared of it becoming brittle afterwards

GREG DOE

Bob,
Your assesment it not quite correct. When the resin cures it takes a certain shape. If the part is heated and reformed to a new shape, and than later exposed to heat again (such as in a hot car) the part will return to the origional form. At my job we received "Checking Fixtures" that were occassionally warped in transportation. We put them in an oven at about 220 deg. F. and then allowed them to cool. By the way "post curing" resin parts at an elevated temperature will allow them to tolerate exposure to higher temperatures later on, but that's another subject. Greg

sensei

We can only lead a horse water... LOL

Bob

Ed Smith

Save yourself a lot of trouble and replace the carbon gear with an aluminum one. The carbon gear will probably delaminate at the "Bend" near the fuselage anyway.

Ed S

Carlos Murphy

My Feedback: (72)

1 1/2" of clearance? Just what kind of plane are we talking? I guessing its a "tail dragger", if its a trike 1 1/2" is enough but if its a tail dragger, 1 1/2" with the tail on the ground is not enough.

Landing gear blanks are cheap anyway, go to your LHS and take a look, bring the old one with you.

How bout retracts? Oh, that's wright, we don't know what kind of plane it is...

You can always cut each leg a couple inches from the axle and make extensions from aluminum that would sandwich a wooden spacer

between the cut ends, just drill holes for small bolts but if were talking about a "disposable" airplane, its just not worth the effort.

trpastor

Yeah, it's a tail dragger.

I'm not sure I understand the extension idea. I'm interested in hearing it out though

HH

Trpastor, Can't you just replace the landing gear with longer leg gear? That seems like the most simple thing

trpastor

Yeah, I guess so. It's just that it's nice carbon fiber. I was kind of excited about the part, but it might be easier to contact that one company that makes custom landing gear

trpastor

Where can I get some cheap landing gear? Any suggestions?

I guess I could make it. But that seems like by the time I bought all the materials, I spend almost as much and spend a day of time!

Carlos Murphy

My Feedback: (72)

Go to your LHS (local hobby shop) for landing gear blanks, as I already said.

You COULD get one from Tower Hobby but shipping would cost as much as the gear.

As for custom landing gear, try T.N.T., they made gear for my Bud Nosen 105" Cessna and it was perfect, not sure of their web address but they advertise in the model mags.

trpastor

My LHS doesn't have much in the way of landing gear. Do you mean they have blanks that you cut down? You still need the right base and height though. Isn't that hard to find?

Carlos Murphy

My Feedback: (72)

By blanks I mean different sizes of replacement aluminum, fiberglass and carbon landing gear with and without axles.

Most are pre-drilled for mounting to your fuse and DuBro make axles in assorted sizes depending what size wheels you use.

Send to towerhobbies.com for a free catalog, while your on their home page click on...

"Aircraft Accessories".

Scroll down to "Airplane Fixed Landing Gear-Main".

multiwing

Ref. post #5 (Sensei) That's the way to do it. All resin systems have a thermal transition gradient (TG), the point at which the composite will become ductile. ie: G-10 fiberglass has a TG somewhere in the 200 Deg. -F range. If the material is subjected to, too high a Temp. it will become brittle, too low and it will crack in lieu of reforming. Not knowing what type of epoxy resin / hardener is used (neat system, fillers?). Test the part by heating a small section (heat gun & thermometer) in an low-dynamic area, while pushing down with an awl or pointed scriber. When the tool starts to penetrate you've found the TG, record the Temp.
Your goal is to alter the contour over the full length of the gear leg as opposed to a small section. Make a simple wooden mold that's a bit smaller than the required finish size of the gear. Place the gear over the mold, clamping with some sort of a spring, or bungee (if it will take 200+ Degrees.) Don't try to bend to final shape, the active pressure form the clamp will do the reforming.
Place the whole assembly in a Preheated (air circulating if possible) oven, for approx. 30 min. or until you see the part to begin to reshape. If necessary slip on some oven mitts and compress by hand, then tie off, or clamp the gear to conform to the mold. Two schools of thought on cool down. Shut off the oven and allow the composite gradually cool within, or just remove it and allow it to reach ambient Temp. on it's own. Either should be fine considering the epoxy system is of a simple type.
The composite will have changed chemically, and in turn physically, but not enough where you'll ever notice. I've used this technique a number of times on Carbon & fiberglass without issue.
Hope this helps & Good luck.
PB

LouisB

My 2 cents' worth - should you bring the wheels closer together in order to raise the nose, watch out for the lateral balance of the aircraft. You might find the aircraft tends to topple sideways when taxing around.

carrellh

This crude drawing is my take on it.

JohnBuckner

My Feedback: (1)

Trpastor assuming its fuselage mount main gear you will likely find something here that will work:

http://www3.towerhobbies.com/cgi-bin...=RF&search3=Go

They also stock a variety of glass gears. I highly recomend that unless you are after the holy grail of lightweight gear then avoid carbon fibre. When properly designed it has only a slight weight advantage over aluminum but with none of the durability and will not take nearly as much a simple dural gear. Trying to bend you CF will only result in failure.

I understand what you mean about your LHS, unfortunately anymore very few stock gear blanks.

John

exeter_acres

My Feedback: (2)

DOn't know about cheap, but I do know they are good...

http://www.tntlandinggear.com/store/...ne_catalog.htm

Carlos Murphy

My Feedback: (72)

Ditto on TNT,

I sent them exact measurements and got just what I ordered, perfect.

I then installed brakes on them which I controlled with with a BVM Soft Stop brake valve.

carrellh

Carbon Fiber and "cheap" do not go together very well. Hear are two more fairly easy and fairly cheap options.

Jonathan Ott

My Feedback: (25)

TRPastor: Help us out here and let us know what kind and size of plane you are talking about? A pic of the plane would help too. Take it over to Schafers Hobbies and ask their guys, wealth of knowledge there.

If it is a 4Star40, put a 1/2 in. plywood spacer between the gear and the fuselage. If it is a COMP ARF Yak, you are gonna have to go with bigger wheels and a 3-blade prop. Help us help you.

Jon