Stronger gas springs for RV-7 canopy

[N737Z]

I have had my canopy blow down with a wind gust and it broke a corner off. Repair was easy enough, but I decided to replace my stock gas springs, which are very weak, with stronger springs. What a difference it makes! I went from 100n to the 150n and my canopy is much more secure in the raise position.

Gas Springs available from the following link:

http://www.pointswestmarketing.com/liftomat.htm

Regards,

Don in PHX

[Bob Martin]

Don,
Sounds like a good idea.
Thanks for the information.
Can you tell us what Part # is the RV replacement?
and what was the cost?
Thanks,

[flyvans.com]

hi,
we're working on a related issue as well...
in my opinion it's not just the weak springs... the problem is, once they get into the compressed position which is about 15" before closing, they have no upward force any more and the canopy slams down.
what we try to come up is a nice solution that guides the canopy for the last few inches as well as dampens/slows the movement, probably with 2 more small lift struts or so, not yet engineered and decided upon.

anybody with a succesful setup?

regards,
bernie

[terrykohler]

I've found the gas springs used by Van's need to be replaced every couple of years to maintain what I believe is adequate force. On the other hand, putting in stronger springs may create another problem for you in that the compressed spring tends to force the closed canopy forward against the cowl deck. You may be trading one issue for another. I'd recommend just getting new springs every couple of years, if necessary.
Terry

[rvbuilder2002]

Originally Posted by terrykohler

I've found the gas springs used by Van's need to be replaced every couple of years to maintain what I believe is adequate force. On the other hand, putting in stronger springs may create another problem for you in that the compressed spring tends to force the closed canopy forward against the cowl deck. You may be trading one issue for another. I'd recommend just getting new springs every couple of years, if necessary.
Terry

Terry knows of what he speaks.

[N737Z]

The new set of gas springs are the exact dimensions of the stock springs and actually have a better damping action to slow the extension. The structure per Van's plans is more than strong enough for the slightly greater force of the stronger springs. I don't have the part number handy, but write down the number off your stock springs and go to the sizing chart on the web site to get the identical size unit with the next step up in force.

Regards,
Don

http://www.pointswestmarketing.com/liftomat.htm

[rvbuilder2002]

Originally Posted by N737Z

The new set of gas springs are the exact dimensions of the stock springs and actually have a better damping action to slow the extension. The structure per Van's plans is more than strong enough for the slightly greater force of the stronger springs. I don't have the part number handy, but write down the number off your stock springs and go to the sizing chart on the web site to get the identical size unit with the next step up in force.

Regards,
Don

http://www.pointswestmarketing.com/liftomat.htm

The springs push fwd on the canopy frame when the canopy is closed (by design). I have seen the canopy position change by as much as 1/8" fwd after installing the gas springs (all canopy fitting done without the gas springs installed).
Adding an even higher newton value spring could make this even worse.

[aparchment]

This question will reveal how much time I have spent looking at my canopy plans, but why can't we just attach the gas shocks to the canopy hinges and have them push up from below? This is how the canopy works on the Lancair Legacy.

[Bob Martin]

Originally Posted by aparchment

This question will reveal how much time I have spent looking at my canopy plans, but why can't we just attach the gas shocks to the canopy hinges and have them push up from below? This is how the canopy works on the Lancair Legacy.

I have seen this on another RV-6 tip up. I wondered about why it was different, until now!
Good thread.

[N737Z]

Excellent input. I have not had any movement, but I will certainly monitor, evaluate, and report back with any adverse affects. thanks Gang.
don