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Better than a gas spring, which distorted my canopy when closed. Worth the weight.

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I have been trying to find something, like a low pressure gas spring, that will [url]dampen/slow canopy movement[/url]in both open/close direction.

At the moment I have a low pressure gas spring that does no more than a cable would do ie at full extension, hold the canopy in the open position.

I have tried, without success, to find a pneumatic cylinder that has the same/similar dimensions as the gas spring, with the idea that I could plug the air in/out hole(s) and then drill plug, starting with a 1 mm hole. Increase hole size as required. This would have the effect of damping the open/close movement and at full extension hold the canopy in place.

You can get adjustable gas springs.

Though IMO a spring that restricts your ability to quickly whip a canopy shut to save it - when a less than situationally aware "pilot" nears you fails to shout "clear" as they hit their starter and prop blasts you - could leave you with a whipped and damaged canopy. Wind gusts do the same.

I'd like to think my canopy is ALWAYS under supervision or locked. I know that is not quite true - but I aspire to it!

YMMV

Guilty as charged - that is having a canopy damaged by an unexpected gust of wind (in Australia known as a Willy Willy)

My concept (yet to find appropriate parts) is a dampened opening/closing. The hope is that slamming/jerking open/shut, by errant gusts, would be prevented/minimised.

As you correctly suggest - the most cost effective, lightest and foolproof method is simply remembering to hold onto the opening canopy and closing/latching it on exiting the aircraft.

That's clever karmarepair! Have you used it yet? Would like to hear your thoughts on how it is working out.

This all got started when I saw Pete Fernell's setup when I flew with him in Kingman AZ, where the wind blows ALL THE TIME. He used a gas strut. I was INITIALLY happy with my gas strut, the installation of which I described here [url]https://www.facebook.com/groups/158111198219011/posts/988457398517716/?__cft__[0]=AZUlFj9T6m8HHi2lM6a89ApyklL6bOLxuX6DXKgDR0ww6bahAn6dtflLcSpoeQmadn8v_MzH2etIgPJsCDtgPIguJJNs8bedOFK9-FVUocFtc4cr812auBnrJY-c2wYNgs-Opar9_zEvCllyTBsKpUjg&__tn__=%2CO%2CP-R[/url], but came to realize the force when it was compressed was distorting the somewhat flimsy frame. Pete's frame hade herkier gussets and was overall stiffer.

The hatch spring is a good bit shorter than the gas strut, particularly extended, which made the geometry pretty restricted, I'd rather have the canopy a little farther "over center" than it ended up being. They have longer hatch springs with different mounting hardware. I also tried various extension springs from the hardware store, but I did not find a "sweet spot" of a spring that would stay in column, but easily release, and had the length I wanted.

I ditched the Sonex limit wire, which as a former rigger, had the wrong fittings, didn't "lead fair", and had no shock absorption. I replaced it with knotted paracord, adjusted so that it's JUST long enough to allow the spring to fall into column. I has some shock absorption, it leads perfectly fair, and it complements the "limit wire " in the hatch spring that keeps that assembly from over-extending.

I like it a LOT, but my airplane is still at the 98% done, 98% to go stage, so it's not battle and ramp tested.

GAS SPRINGS

FYI - for anyone wanting to go down this rout for a canopy strut;

"but came to realize the force when it was compressed was distorting the somewhat flimsy frame"

This is completely unnecessary WHY? because gas springs can be order/purchased with a wide range of opening forces. Karmarepirs strut is clearly way too" strong".

As I do not need/want assistance in opening my canopy, I ordered my gas spring with the lowest opening force availably. I hoped that the gas spring would have a dampening effect on opening/closing of the canopy. The dampening effect has not happened. My gas spring is essentially an over complex/heavy/costly telescoping strut, that holds the canopy in the open position.

If anyone knows of a product, similar in dimension/appearance to a gas spring, that will act to dampen the opening/closing action of my canopy, please send me the details.

Skippydiesel is not wrong, exactly. The gas strut I used was 15" long & 10 lbs force. It IS possible to find gas springs with lower force, but NOT easy, especially in the length I'd want (at least 9 inches, and preferably more). This one MIGHT work out https://www.guden.com/Item/Small-Gas-Sp ... GN56-005-A After taking off the gas strut, I I was looking for a hold open, with as near zero force when closed as possible. So far, I'm happy.

I think what Skippydiesel is looking for, and I agree, it's a good idea, is a damper; https://www.guden.com/itemdisplay/standard-dampers or https://www.guden.com/itemdisplay/self- ... ng-dampers

That spring arrangement is interesting.

Skippydiesel wrote:GAS SPRINGS

FYI - for anyone wanting to go down this rout for a canopy strut;

"but came to realize the force when it was compressed was distorting the somewhat flimsy frame"

If anyone knows of a product, similar in dimension/appearance to a gas spring, that will act to dampen the opening/closing action of my canopy, please send me the details.

Hey Skip

To stop the distortion I used a small piece of angle with rubber glued to it as a stopper see this link for a photo. I also beefed up behind the turtledeck bulkhead with some angle brackets, these brackets may or may not have been overkill.
https://images.app.goo.gl/uvQwqt7ZQrUgzvPv8
Where I positioned my strut it goes over centre in both the closed and opened positions. Which means it puts some downward pressure on the canopy when closed also. The details of my strut and fixing locations are here in a 7 year old post. viewtopic.php?f=3&t=2242&p=16693&hilit=gas+strut#p16693
After 12 years I'm on my second strut. The first one ran out of pressure at about the 10 year mark. I went to a local strut guy re gas guy he had new ones in many sizes and pressures. A new low pressure one cost me about $25..
Steve

I like the sound of Karmarepair's Guden two way dampers BUT as a special order/run the cost may be prohibitive. Will make contact with Guden and see what they can do for me.