Gas strut canopy support CH 601HDS

[davidtod]

Hi,

I'm looking for a bit of advice about the support rod for my CH 601HDS canopy. It currently has a two piece hinged rod with a cylindrical plastic block that slides down to secure the rod when the canopy is open. The canopy can open from both sides and the rod is hinged top and bottom to allow this.

My question is whether it would be possible to replace this two piece rod with a single gas strut, similar to that found in the boot of a car? As far as I can see it would still be able to open from both sides since the ends will be hinged. I'm not sure if a single gas strut would be strong enough to hold the canopy up? Or whether it would introduce stress which could crack the canopy? Has anyone attempted this on this model of aircraft with the original side opening canopy?

Thanks,

David

[dmcnicholl]

I don't doubt that gas struts could be used, but a word of caution.

A friend fitted gas struts to the gull wing doors on his aircraft, not a Zenair, and all seemed well…until a door opened in flight.

Post incident investigation in the hangar determined that the door latching plate on that side had a slightly 'relaxed' geometry that made its latching divergent, by which I mean that the more the door eased open the less positive was the connection of the latch. So while the real issue was in the arrangement of the door latch fittings it was also thought that the constant pressure of the gas strut could well have been contributory to pushing the door out of security allowing airflow to do the rest.

So I'm not saying don't do it but I am saying that if you do make sure you understand all the ramifications. I have another friend who had the side-to-side canopy of a Zodiac open in flight. He didn't enjoy the experience and his current Zenair has the forward hinging canopy.

[davidtod]

I don't doubt that gas struts could be used, but a word of caution.

A friend fitted gas struts to the gull wing doors on his aircraft, not a Zenair, and all seemed well…until a door opened in flight.

Post incident investigation in the hangar determined that the door latching plate on that side had a slightly 'relaxed' geometry that made its latching divergent, by which I mean that the more the door eased open the less positive was the connection of the latch. So while the real issue was in the arrangement of the door latch fittings it was also thought that the constant pressure of the gas strut could well have been contributory to pushing the door out of security allowing airflow to do the rest.

So I'm not saying don't do it but I am saying that if you do make sure you understand all the ramifications. I have another friend who had the side-to-side canopy of a Zodiac open in flight. He didn't enjoy the experience and his current Zenair has the forward hinging canopy.

Thank you very much for your response. This was something I was worried about, i'll need to think about it carefully. It might be an option just to replace/modify the current support rod to make it a bit more durable. The canopy latches on my 601 have been bolstered by snibs on either side to lock the canopy in place. I might end up installing the forward hinging canopy but i'm struggling to find details on the upgrade process and parts required to upgrade a 601 to a 650 canopy. With my level of experience I am uneasy about performing this myself.

Thanks for your help,

David

[dmcnicholl]

David,

I have no idea if the forward hinging canopy is retrofittable (?) to the Zodiac. The one owned by my friend is a different aircraft to the one that opened in flight. I suppose anything is doable but it may not be easily doable. I don't know.

Thinking back rather further I have other friends who have had canopies open or doors come off in flight. Fortunately none of these events resulted in an accident other than perhaps to their underwear but it may be a more common occurrence than you'd think. One of these was to an early type of gull wing door which also had secondary security fixtures, not your snibs but something similar. That was all right as long as he remembered to fasten them before flight. Well, one time he didn't and the door opened right after take off. We saw it happen. We saw the erratic flight path that resulted as he tried to tame the thing before he gave it up and concentrated on the 'aviate' part of the equation.

Yet another lost a door over the Pentland Firth.

Not trying to put you off, but we none of us have enough time to make all the mistakes ourselves and just maybe we tend to dismiss hatches and latches as 'minor' items. They're not.