Eagler's Nest
Airframes => Single Seaters => XL => Topic started by: edpogue on February 17, 2018, 06:13:46 PM
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I’m looking for a fiberglass leaf spring similar to the one Les Homan is using. I haven’t had much luck with web searches.
Any help would be appreciated
Ed LEXL G38
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The Flit Plane uses solid round fiberglass rod for the tail wheel spring. The call out in the plans is for 3/4 inch rod.
It is available at Max Gain Systems (https://mgs4u.com/product-category/fiberglass/page/3/) as Ham radio mast material.
They also have a section where they offer rod for main landing gear legs for ultralights and PPCs... Titan Tornadoes and others use them.
The screen shots below show bolts in horizontally drilled holes. Perhaps that is why the rod looks more like 7/8" or even 1 inch. If you use this setup, use vertical bolt holes and Dutchman clamps on the tubing where the rod enters or leaves each tube. Loose fitting rods invite splitting through horizontal holes from spirited vertical landing forces...
The last attachment is the Dutchman before welding.
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What are the advantages of a fiberglass spring? Lower weight, better behavior?
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Lower weight for sure (.75"rod) ... Wheel landings on less than fully improved runways probably advised...
Plastic disc is only bearing for tail wheel steering.
If there is interest, I will endeavor to locate the drawing....
I jumped up and down on it, but attribute the failure to the looseness because of no Dutchman clamps and the horizontal bolt holes .
I figure I put at least 300 lbs on it and believe the 3/4" would be fine with no slack in the system.
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What are the advantages of a fiberglass spring? Lower weight, better behavior?
There was a discussion years back on the Yazoo site about using compound bow limbs for the tail spring. I don't know if anyone ever tried it, but sounds very plausible...
There is such a thing as too light to endure the current mission profile. The thing about tail wheels and springs is unless the spring breaks short enough to let the rudder hit, it usually amounts to extra braking power...
The FlitPlane wheel is very light and seems a little delicate. Probably needs to be on the thorough pre-flight item list.
I think the 3/4" fiberglass rod would be adequate with a solid mounting. Me jumping up and down on it with 250 lbs of romping-stomping airborne hell only caused a split through the horizontal drilled hole, not a total failure.
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Bought myself some rod from MGS to give this a try
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This rod is mighty stiff. Will it flex and not break my plane?
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How long is the rod you bought?
You will wind up using 12 or 14 inches of it and it will be very flexible with weight on it.
With springs longer is more flexible.
You could start longer and keep cutting it shorter until you are happy with it...
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Bought a 2’ section
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I flew my pterodactyle ultralight for 20 years with 7/8" dia. fiberglass rod main landing gear and never had one crack or break and I had some hard landings while teaching myself to fly.
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Guys, I have been sitting on the side line here, and I have to speak out.
When some say, I have had 3/4" or 7/8's fiber glass gear and it has never broke, is like saying, " I have a steel knife that was really good but....as you all know there are..... (many many kinds of steel). So all we know is that someone said that someone said this is a good knife...."
There are so many kinds of fiberglass rods that the simple word "fiberglass" can not begin to detail what is being used. Some is designed to be flexible in one direction (side to side) some extremely rigid, some has tremendous tensile strength, some not so much.
and some, if you drill a hole into it, anything beyond that hole is just extra weight, no additional strength from the hole on!
Just as the fellow that started this discussion on tail wheel spring said, how he builds it, has a huge impact on how it is going to work. The same goes for how this "fiber glass rod" is built.
All I am saying is , fiberglass rods could fill the apple and orange cart nicely... pretty hard to put all in one basket and say they are the same. Except for looks in this case.
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Im not looking to make mains out of fiberglass rod. Im looking to replicate the flitplane setup on the tail, but im a little concerned that it might transfer too much force to the frame.