1981 Cobra trailer gas struts

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

On Sunday, January 5, 2020 at 7:38:23 PM UTC-8, Matt Herron (Sr) wrote:
I have a new pair of Cobra struts that I would be happy to sell, cheap.
These are the stats: N= 850; Art-Nr = 3 500 30; Herst-Dat = 0605
Dont\'t ask me what these figures mean. I have no idea!

A reminder: Cobra struts have a small hole in the port strut, the purpose of which is to put a safety pin in when the top is up.

A reminder: Cobra struts have a small hole in the port strut, the purpose of which is to put a safety pin in when the top is up.

Note that the hole is NOT through the gas strut rod itself, but through the square telescoping tube that houses the gas strut.

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?

On Wednesday, March 18, 2020 at 12:41:44 PM UTC-7, Tom BravoMike wrote:
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?

Cold weather failure is often the first sign that its time to replace.
Jim

Low ambient temp suggests low strut pressure...don't care if car rear hatch or glider trailer big cover.... works decent when warm, sucks when cold....
Lube pivot points at a minimum....likely replace gas struts.....
What is cost of struts vs. cost of glider when trailer cover crashes on glider????
I have have worked on sailplanes after "stupid stuff"..... gas struts are relatively cheap in that case....and you fly...
Your choice....