Carbon fiber vs Aluminum landing gear
 

Hello,
I am thinking about replacing the aluminum landing gear on my goldberg 67" edge 540 with a carbon fiber landing gear. The gear got bent a few too many times and now only takes a little effort to loose its shape. Is the carbon fiber gear much stronger than the aluminum gear to with stand a few hard landings without breaking or am I just wasting my $$ on a carbon fiber gear?
Any info would be very much appreciated.


Graham

RE: Carbon fiber vs Aluminum landing gear
 

A few facts that might help you are the Specif Gravity (OR weight relationship to water @ 62.4#/CF) of carbon epoxy composite is 1.54, where 6063-T6 aluminum is 2.71. This equals a 75% weight saving if you go size per size. But The tensile modulus (Or strength) of carbon epoxy composite is 20.3, where 6063-T6 aluminum is 10. So this means you can use half the material to get the same strength. Bottom line it even if you only cut the material thickness by 1/3 and go carbon composite you are reducing you weight at lease in half!
Charlie

RE: Carbon fiber vs Aluminum landing gear
 

Hi P51p
I put a Dubro carbon main gear on my 7 lbs C3-Cub over one year ago. I had three bad crashes with it and never hurt the main gear. I believe the gear flattend out during the crashes. They are much better than aluminum gear. I purchase another Dubro carbon main gear for use on my Canard when i rebuild it.

RE: Carbon fiber vs Aluminum landing gear
 

Hi ByLoudDesign,
Great info, but weight is not a concern. I need durability to withstand a few hard landings.

RE: Carbon fiber vs Aluminum landing gear
 

If the two are of equal size the CF gear is going to be MUCH stiffer & stronger.

CF can redily crack however, especially during an impact or hit, etc.

RE: Carbon fiber vs Aluminum landing gear
 

I think aluminum is better for a beginner. I personally broke 3 carbon fiber landing gears trying to learn to fly an Extra 260. (including a graphtech set which are very strong but brittle) The one set of aluminum I used got bent back several times before a dead stick that finally broke the aluminum. I'm doing well enough now that I use mostly carbon. But back then aluminum was best for my skill level.

I hope this info helps you decide.

Scott

RE: Carbon fiber vs Aluminum landing gear
 

Yeah I'd rather have the gear absorb the impact than having to rebuild the fuselage bottom after a hard landing.

IMHO it's much easier to replace the gear.

RE: Carbon fiber vs Aluminum landing gear
 

The real problem you're going to have is finding any replacement gear to fit. If you find both aluminum and CF, you're lucky.

If you find any, check out it's specs to see what weight airplane it's supposed to support. If your airplane weight is near the max for that gear, you won't be gaining much using it. Keep looking.

Your real solution is to take the measurements off your original and simply find some replacements that match.... or come close..... and that will support the weight. If one of them is CF, it usually works somewhat better than aluminum. It will flex (if it's specs match your weight) enough and it'll be a bit less prone to fail. However, it also will cause more damage to the fuselage in the event of a damaging landing or crash. Everything has a trade off.

BTW, it would be nice if us modelers could decide details like whether or not to use CF or aluminum and then bop on down to the LHS and pick whatever we decided to buy. But most times you are lucky to find a replacement at all. Much less have a choice.

RE: Carbon fiber vs Aluminum landing gear
 

BTW, if you use either type and it appears to be more than adequately strong for the airplane, consider using nylon bolts to attach it. If the gear is stronger than the original stuff, impacts are going right into the fuselage unless you can provide a breakaway capability. Nylon bolts provide that.