1981 Cobra trailer gas struts

David - One comment from someone that has never replaced a Cobra strut (but might have to someday).

Please take lots of pictures of your replacement process and publish them for the benefit of all. Also publish a list of resources and data you found and used. Years ago I did this for installing Wederkind sleeves on L'hotellier fittings and I still get a thank you note from time to time.

Ditto message to anyone replacing internal struts.

Thanks, John OHM Ω

Will do. That's a good idea. I've had mine off several times for various reasons. It's not difficult, but does require caution for some obvious reasons, others no so much.

David

On Wednesday, March 18, 2020 at 11:13:23 AM UTC-5, John DeRosa OHM Ω http://aviation.derosaweb.net wrote:
David - One comment from someone that has never replaced a Cobra strut (but might have to someday).

Please take lots of pictures of your replacement process and publish them for the benefit of all. Also publish a list of resources and data you found and used. Years ago I did this for installing Wederkind sleeves on L'hotellier fittings and I still get a thank you note from time to time.

Ditto message to anyone replacing internal struts.

Thanks, John OHM Ω

BTW, how do I know it's time to replace the struts? I have a 1984 Cobra trailer with the square telescoping tube; with low winter temperatures the top wouldn't stay up, but it does when the temperature rises during the flying season. Should I get new struts right now?

Guys it's been a while since I followed up on this post. I located a manufacturer in Oregon that will make custom size and force gas struts. The company is called American Gas Springs. They have a website if you want to check it out.

Richard Pfiffner ordered a couple for his Cobra trailer and they worked fine. I am in the process of ordering some as well. I've had some difficulty getting a response, but I thought I'd put it out in case there was anyone else who wanted to add on to the order.

Right now I am ordering standard sized Cobra struts for pre 1984 trailers. These are the trailers with the struts on the outside. I am also ordering the same for a Komet trailer of the same vintage. If you want to PM me I can give you my specs.

David

On Friday, December 13, 2019 at 5:54:33 AM UTC-7, David Cleveland wrote:
I have a 1981 Cobra trailer designed for a single seat glider. The trailer design is of the type that has the struts located on the outside of the trailer, with an aluminum top. I am looking to replace the gas struts.

I have contacted Wings and Wheels. They have been very helpful, but they do not carry the struts for this design. They also mentioned that Spindelberger/Cobra do not carry the item.

I am looking for two things. My struts were painted in the past, so I am unable to get the read the strength of the strut. I am also looking for a recommendation for replacement or refurbish.

Thanks

David Cleveland
Salt Lake City

Yeah. Whoops. That last post was from David Cleveland. I was using someone's else's computer.

David

LS Technologies in Canada is awesome. Our club has ordered multiple sets from them.

Randy "AV8"

On Tuesday, March 17, 2020 at 9:11:53 AM UTC-7, David Cleveland wrote:
Yeah. Whoops. That last post was from David Cleveland. I was using someone's else's computer.

David

I also used American Gas Springs for my Cobra Trailer. I used 1300 newtons.. Measure the extended length and the retracted length and be sure and include the correct fitting lengths in the calculation. I held the top up with a crane and replaced the struts. Be especially specific on the extended length and retracted length. If it is too long the mechanism will go over center too short and the top will not close. I went to the factory 40 miles north of me Medford, Or and picked up the gas springs. The make lots of stuff that involve gas springs.

Richard
www.craggyaero.com

David - another data point if it helps...several years ago I replaced the struts on my 1978 vintage Komet trailer with off-the-shelf units from Bansbach Easylift. They can do any custom strut you want but lead time (at that time) was 5 weeks. I was able to work with one of their tech support guys and got what I needed with one of their "quick ship" struts. We had to match specific end fittings with one of several base struts available to get required compressed and extended length but they were super helpful, provided engineering drawings to confirm specs, and responded very quickly.

Believe their struts are actually manufactured and stocked in Germany but I had mine in ~2 weeks. I ordered 1600N and they work fine...certainly firm but not objectionable to close. I had the same experience as others...the top of that trailer is crazy heavy so exercise reasonable care.

Mark Bearden

I finally was able to get some custom gas springs made and installed. They work very well. The short story is that I used a company in Oregon, American Gas Springs. I know others have had good results getting custom springs made by other sources, but I wasn't able to find any who would make small orders.

I used 1200N for a final gas spring force. A detailed description of the process, as well as the dimensions and install are described in a document available on Google Drive:

https://drive.google.com/file/d/1oEe...ew?usp=sharing

On Thursday, June 18, 2020 at 4:53:33 AM UTC-7, David Cleveland wrote:
I finally was able to get some custom gas springs made and installed. They work very well. The short story is that I used a company in Oregon, American Gas Springs. I know others have had good results getting custom springs made by other sources, but I wasn't able to find any who would make small orders.

I used 1200N for a final gas spring force. A detailed description of the process, as well as the dimensions and install are described in a document available on Google Drive:

https://drive.google.com/file/d/1oEe...ew?usp=sharing

I used the same company American Gas Springs but I used 1300N. Easier to life and almost goes up by itself. Pull some to get down.

I picked mine up only 40 miles north of me. They have an extensive product line of gas springs etc. for everything and a really nice manufacturing facility.

Richard
www.craggyaero.com