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Sep 16, 2019, 08:02 PM
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Wire Landing Gear Question


So recently I had aquired a Top Flite Sierra 40 Trainer to learn and start out on in my nitro venture. The landing gear did not come with it. With that said, it is supposed to be 5/32" wire landing gear. My LHS is currently out of stock in 5/32" wire to make the gear from. Is there any reason why I could not use 3/16" mild steel wire and temper it in the oven to make my gear from. The only things I would have to do to make it work would be to drill out the wheels for the larger diameter gear, drill the holes in the fuselage to accept it, and lastly I would just have to widen the slot on the bottom of the fuselage for the gear to lay side by side in it. I have already made the gear and tempered it and have it sitting here and it is very strong and does not bend. Hoping I get the ok that it will work so I can keep going on my plane. If this is not an ok solution, why might that be? I will still buy the nose gear from the LHS as they have it in stock and making that may be more difficult. Thank you.
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Sep 16, 2019, 08:21 PM
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earlwb's Avatar
Yeah you could use 3/16 piano wire for the landing gear. Granted it is a little bit heavier and more stiff. I have done it before too. it should not be a problem. yes it would be much easier to buy a nose gear setup. Trying to make that coil spring on the nose gear strut is very hard to do.
Last edited by earlwb; Sep 16, 2019 at 08:23 PM. Reason: typo
Sep 16, 2019, 08:44 PM
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Thank you.
Sep 17, 2019, 10:07 AM
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Quote:
Originally Posted by NEW222
Is there any reason why I could not use 3/16" mild steel wire and temper it in the oven to make my gear from. .
I don't know if that will work. Piano wire like in the LHS is already tempered I believe and very hard to bend but will also spring back. I don't know what mild steel wire is.
Sep 17, 2019, 10:41 AM
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earlwb's Avatar
I use a hammer and vice or anvil to do it. You get basically one try at bending the wire. Now if you had a large wire bender you could use it, but the small wire benders won't do it. But yes the piano wire is quite stiff and springy.

To make the nose gear strut, you use mild steel ( a alloy that lets you harden it). You make your strut including the spring coil. Then you harden it. The hardening process is a problem as normally you would use a furnace to heat it up red hot and then quench it in oil. The carbon in the oil hardens the outer surface. it should then be quite springy when you try it out. Trying to use a torch may not work well as it is difficult to get it all heated up evenly. Hummj, maybe using a BBQ grill, and a blower to to air into it might work though.

But of course it is mush easier to just buy the nose gear setup already made.
Last edited by earlwb; Sep 17, 2019 at 10:43 AM. Reason: add more info
Sep 17, 2019, 05:17 PM
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ChillPhatCat's Avatar
I have made 3/16 gear with just a vise... measure twice though as mentioned above, you can’t reverse a crease... but you can bend it more or less to fine tune. Mild steel will be a poor choice, tempering with an oven is tricky business... music/piano wire is already tempered like spring steel so it’s perfect for our purposes. Whatever you do, don’t use a torch, it destroys the tempering.

Re-reading your post. I would bet that you’ve hardened it and not tempered it (it should bend a little without breaking and just go right back if it is tempered). It might just snap on the first hard landing... but you can try it, probably won’t hurt anything if it fails.
Last edited by ChillPhatCat; Sep 17, 2019 at 05:22 PM.
Sep 17, 2019, 06:00 PM
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Bend Landing Gear


Go get a 3/16" chain saw sharpening file and file a rounded groove in one jaw of your vice. The bigger the wire the bigger the groove. Put a leather work glove on your left hand. Grab the wire and pull it towards the groove, now hit the piano wire hard with a soft face or a dead blow hammer. you have to keep the pressure on with the left hand. Keep hitting it until the desired bend is achieved.

Kip
Sep 17, 2019, 07:39 PM
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Thread OP
Thank you.
@ChillPhatCat, I think you are correct. I just now realized my mistake, and do believe I meant to harden it and not temper it. Thank you for finding my mistake.
Sep 17, 2019, 09:58 PM
Registered User
Mild steel will not harden or temper by heat treating. It can be surface hardened with heat and Casenit but that won’t make it springy. It will just crack. A hardenable steel is first hardened as mentioned, getting it red hot and then quenching in oil. Then it is drawn or tempered by bringing it to a lower temperature in the 500-900 degree F range (depending on what is wanted) and cooling it very slowly, as in over a period of hours. That’s where the springiness is developed.
Sep 17, 2019, 10:57 PM
fix-n-fly
If you are planning to go with tricycle landing gear, you could buy the front gear from some place like Tower Hobbies or Sig Manufacturing (sigmfg.com) and get dural gear for the mains. You can buy the mains in either fiberglass or metal. Sig Manufacturing should have something - if nothing else look at the dural gear for the Sig Four-Star 40. The nice thing about Sig is you could talk to one of the engineers there and tell them what you have. He could recommend a set up for you if desired.


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