Scratch Landing Gear Question

[Shadow31]

Hello!
Me and some of my classmates are working on designing and building an rc aircraft from scratch, for a project. My job, currently, is to design the landing gear for the aircraft. Due to constraints given to us and a required payload, our final design is roughly 6 lbs when fully loaded; I've been looking online, and using piano wire seems to be a very good way for us to minimize the weight. However, none of us have experience with this, so we aren't sure what gauge of wire to use. I'd assume we should use a triangle-truss for the wire, and have been seeing a lot of sites saying to use 0.1" wire, but that's for lighter aircraft generally. Do any of you have any recommendations for us?

Thanks for your help!

 

[Spastickitten]

I would use thicker wire, and I would use string to unsure they do bend out. Or you can do tricycle.

 

[RAM]

6lbs.

I would use a version of this idea (from the real Zenith STOL).

 

[menachg]

just take some wire hangers and twist them to required shap(use your imagination)
as shown inhttp://flitetest.com/articles/wire-hanger-landing-gear
the most important part in my opinion is the connection to the plane itself the rest may bend or break but if the connection is loose it they would just fall from under it
is the spot you connect them to is hard enough to put screws?

 

[razor02097]

6 lbs is nothing to mess with. I don't think I would use wire for it. If you want to minimalize weight but have strong landing gear you could make the main gear from 2mm aluminum plate then use some cable runs from the wheel axles to the opposing leg to reinforce it.

Does your school have a metal shop?

 

[Tater76]

I don't think piano wire will hold 6lbs. look at aluminum stock for this. Maybe 1/4" square stock? or plate. Check out this setup https://www.youtube.com/watch?v=9xtZrK49k2k

 

[mactek]

I recently built some landing gear for my scratch built flitestick which ways probably 2lbs or so. I bent piano wire to the shape landing gear i wanted and then i used instamorph which was shown on a recent flitetest video to create a plastic landing gear which i molded around the piano wire. I can take a picture when i get home from work. Mine isn't really pretty because i was in a rush when i did it but it is super strong and has a nice spring to it. Using this method you could build 20 sets of landing gear for around 16 bucks. To attach to the plane you just drill a couple of holes in the plastic part of the landing gear and screw to a paint stirrer you have glued into the fuselage.

 

[willsonman]

I would use 1/8" piano wire.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXR936&P=ML
It is possible to bend it to shape by hand and I would connect the different pieces using thin copper wire and solder. The thin copper wire can be found in a craft store and is used for creating floral arrangements or beading jewelry. Wrap the copper wire around the joint and apply flux liberally. Use a butane or propane torch to heat the joint and apply the solder. You will need it HOT to make sure the solder wicks in everywhere. Its fairly easy to do without burning your house down. With the right design you can make this a very strong set of gear. Knowing nothing about your plane design I cannot make any recommendations. I've used this size wire on my 9-pound P-47 as well as my 7-pound AT-6.

 

[Spastickitten]

I f you think of how the trojan or the skymule's landing gear is made, it is straight down and very simple, but it can hold a lot of weight

 

[wilmracer]

I would use 1/8" piano wire.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXR936&P=ML
It is possible to bend it to shape by hand and I would connect the different pieces using thin copper wire and solder. The thin copper wire can be found in a craft store and is used for creating floral arrangements or beading jewelry. Wrap the copper wire around the joint and apply flux liberally. Use a butane or propane torch to heat the joint and apply the solder. You will need it HOT to make sure the solder wicks in everywhere. Its fairly easy to do without burning your house down. With the right design you can make this a very strong set of gear. Knowing nothing about your plane design I cannot make any recommendations. I've used this size wire on my 9-pound P-47 as well as my 7-pound AT-6.

I'm with willsonman here. Piano wire at that diameter will work fine for 6+ lbs as long as you think through the geometry and use the soldered joints as he suggested. Without seeing your design we can't really speak to the best way to design the gear but I would expect piano wire to be more than adequate.

Selecting some low-bounce wheels might be a good idea as well.