Any Bungee Covers Out There ,again!!!!!

[Ragwing nut]

Re: Any Bungee Covers Out There ,again!!!!!

Yes, three screws, but none supporting the outer cornors. The bungee cover is basically a flap of aluminum in a high vibration, turbulent slipstream area attached only in the center. Crawl under your T sometime and hook a fingernail under the aft inboard cornor of a bungee cover...moves awful easy!

The center inboard screw seems to be the one that's causing the most trouble. I have 4 examples of used bungee covers here. ALL are cracked around that center inboard hole, 3 of the 4 covers have been repaired in that area and then cracked again.

I think Bill has the right idea: the covers are forced to flex around that center screw every time the gear moves...and if there's even a small gap between the bungee cover and the fuselage you get vibration, again focused on that center inboard screw. vibration=movement=work hardening of aluminum=cracking

Yup. Some sort of spring action would likely fix it.

Bob Gustafson

The cover is permanently fixed to the gear and moves with the gear. Correct there is no other attachment inboard other than the central screw. Attaching a spring to the cover will only make the problem worse. I still say the cover is interfering with the wood gear fairings or the bump stops are wore out or gone causing the problem.

Mike

[Pearson]

Re: Any Bungee Covers Out There ,again!!!!!

Maybe if I leave a couple of extra tabs under the gear legs of my project plane, along with a stick of mild steel rod, and park the acetylene rig close by, the tooth fairy will solve the problem for me.

[mulwyk]

Re: Any Bungee Covers Out There ,again!!!!!

A quick update on my bungee cover experiments:

Gary Austin sent me a nice-but-cracked pair of bungee covers to reproduce.

I made a fiberglass mold from them. Photos here (click on "bungee cover").

So far, I've made three sets of composite bungee covers in the mold. I wanted to use Professor Berle's Spring Principle, so I researched composite springs. Turns out, composite springs are fairly common. Both Volvo and Corvette have used composite leaf springs (a bungee cover could be viewed as a thin leaf spring). The Corvette springs are made of E-glass and polyester resin, so I decided to make my bungee covers from the same material.

I've made the first sets of bungee covers with two layers of E-glass cloth overall and two extra layers in the area of the mounting holes. They weigh slightly less than the aluminum covers (3oz. composite vs. 4 oz. aluminum), and are nicely flexible. I'm thinking of trying 3 or even 4 layers of the E-glass on the next batch, but I don't want to make them too heavy or too rigid.

Bob Gustafson

[Marv]

Re: Any Bungee Covers Out There ,again!!!!!

A quick update on my bungee cover experiments:

Gary Austin sent me a nice-but-cracked pair of bungee covers to reproduce.

I made a fiberglass mold from them. Photos here (click on "bungee cover").

So far, I've made three sets of composite bungee covers in the mold. I wanted to use Professor Berle's Spring Principle, so I researched composite springs. Turns out, composite springs are fairly common. Both Volvo and Corvette have used composite leaf springs (a bungee cover could be viewed as a thin leaf spring). The Corvette springs are made of E-glass and polyester resin, so I decided to make my bungee covers from the same material.

I've made the first sets of bungee covers with two layers of E-glass cloth overall and two extra layers in the area of the mounting holes. They weigh slightly less than the aluminum covers (3oz. composite vs. 4 oz. aluminum), and are nicely flexible. I'm thinking of trying 3 or even 4 layers of the E-glass on the next batch, but I don't want to make them too heavy or too rigid.

Bob Gustafson

Bob You do good work. They look great. Marv

[Richard Boyer]

Re: Any Bungee Covers Out There ,again!!!!!

ok. you fiberglass guys are amazing. When I work with that stuff all I get is a really big mess.

[N74DV]

Re: Any Bungee Covers Out There ,again!!!!!

I've made a few customer fiberglass fuselages and cowlings for RC scale models in the past years and am going to make up a mold for these bungee covers so that I can produce them consistently and quickly from either fiberglass or carbon fiber.

BTW Bob, yours look nice and I'd say you could go another layer and still be fine on weight. Did you oversize them a bit?? My aluminum covers just barely have enough room when the bungees extend on a stiff landing.

[VictorBravo]

Re: Any Bungee Covers Out There ,again!!!!!

Professor? The only higher education I have admitted to on this forum is having a BS degree in advanced BS.

However, I think I just had a brainstorm on bungee covers. This may give me a Master of BS degree

The bungee covers need to be made out of rubberized fabric, molded rubber, or some highly flexible composite.

I am imagining a composite or even aluminum base plate around the perimeter, and a molded (or heat formed) teardrop shape made of rubberixed fabric glued to that base plate.

Rubber glove material... the THIN engine baffle fabric... fabric sewn or heat molded into the teardrop shape and then dipped in the liquid rubber stuff called "Plasti-Dip" that you dip tool handles in... something along those lines. It doesn't have to be heat resistant or even waterproof!

Flexible material means a perfect air seal and vibration proof. NO CRACKS!!! It only has to be stiff enough to hold shape at 100 mph or so.

[rotaxflyer]

Re: Any Bungee Covers Out There ,again!!!!!

ABS vac formed.

I received an e-mail response recently. See below. Also got a photo.

From: Gregory Guy ([email protected])
To: Andy Sinnamon
Sent: Wednesday, December 06, 2006 2:58 PM
Subject: Re: Tcraft bungee cover


Not sure you are still interested, but I have attached a picture.
$30 with shipping.....greg


On 8/8/06, Andy Sinnamon wrote:
I know it has been over two years, but I see a posting that you sell bungee covers formed from ABS for the taylorcraft.

If you still do this, please let me know price and availability.

Thanks,

Andy Sinnamon

[tim]

Re: Any Bungee Covers Out There ,again!!!!!

u should call my friend bob he has every thing u need for ur tcraft