Bungee Replacement

[Robin G]

Can someone give me an idea as to how often, or when one should change the bungee? I was looking around on line and noticed that some planes go years without change. Mine looks to be in good shape but I also noticed that it is not as tight as it used to be and the gear arm that it goes around is beginning to sag just a bit. Anybody have any tips on changing it out?

Thanks.

Robin G

[Slyfox]

You will really appreciate having new bungies or a least bungies you can trust when you have a hard landing, you will know that you won't come up flat on your belly with a wasted prop.

With that said you could go through and change them every year or after each and every hard landing. Or you can just do as I did 3 years ago and replace the whole system with a Grove gear. I did do all the weights and after weighing the old system and the Grove, I figured I gained 25lbs to the aircraft. Now remember that is in the center of the aircraft, so weight and balance is not affected at least it wasn't for mine. It sure is nice to not have to worry about those bungies any more. I love my Grove gear, if I had to do it again, I would do it without thinking, yes I would. It is maintenance free. I went and polished mine and looks great today.

With that said, what the Grove gear has done for me is allowed a purposly done stall at 5ft off the ground for a short short landing. When I do these I bring it in slow and stall it just off the landing site. Flop, right onto the runway, no bounce, but the landing gear really does take a beating. But the Grove keeps on ticking. Than I hit the brakes and stop within 300ft. that's with a calm wind. Really kool.

[kitfoxmod3]

OR, for ALL you ever wanted to know about the subject............
www.vintageaircraft.org/featured/2006%20-%20vol.%2034,%20no.%2008%20-%20shock%20cord.pdf

[Skybolt]

Hi Robin.
A couple of pictures to show what I made to help with the instalation.
Buy a couple of vice grips and with a grinder make the gripping area smoother and create a groove. You can still have some gripping power but nothing that could cut into the bungee. Between me pulling and my wife using the grips, we can slowly wrap (I think 5 times) the bungees around the frame work. Have a look at the manual. It is important that you wrap the correct amount of times.
Eric.

[Skybolt]

Robin.
I found this picture somewhere.
It shows really stretched bungees or the bungees were not wrapped enough.
If you look at the wheels you can see that they are spread wide.
If you look under the belly of the aircraft you can see the top bar of the landing gear is away from the fuselage.

This set up looks like danger.
Eric.

[Robin G]

Thanks to you all for the input. It is much appreciated.

robin

[robmobile1970]

I broke a bungee getting my tailwheel rating and learning to fly in my kitfox. THey looked fine when inspecting them on the airplane. After the break we took them off and noticed there were many frays next to the tubing that you couldn't see from the outside. 2 people with vice grips can replace the bungees in about 30 MIN without too much difficulty. Finding Bungee cord to make your own that is as strong as the stock kitfox bungee is hard. Buying replacements at $75 is more economical than the time you will waste trying to come up with your own. Not sure if they really need to be replaced after a year or not, but removing them for a good inspection during annual would be a good Idea.

[dcy92444]

The vise grip trick is a really good method for replacing the bungee cords. I have replaced mine several times and was alone each time. It takes a few trips up and down but is really not that hard and took less than an hour to complete.

Good Luck

Dee

[Model 2 Madness]

I suggest, as stated below, after a hard landing or yearly. See below what happened to me after a hard landing. The bungee was weakend by age and the safety wire yanked the support frame down. It's all, of course, very fixable.

Check those bungees. If they're old or your gear sags replace 'em.

[lbushrod]

I have a question for the group. I purchased new bungees from Kitfox for my model 2. Debra says that either 5 or 6 turns of bungee on the struts is acceptable. My book shows 5 turns which I was able to get. I might be able to squeeze another turn but wonder on the life and tension of the bungee.

A friend has a model 3 which I helped replace the bungees. With three of us we were able to get 6 turns on his gear but it appeard to me that they were stretched to the max. He also had a hard landing and wound up bending his cross members in the cockpit which had to be straightened and new gussets welded in.

Which is better? What are your thoughts? I wondered if the 6 turns put too much pressure on the airframe in the hard landing and would 5 turns have been better.

Pete