Canopy ground ventilation latch?

[13brv3]

Greetings,

I've seen a few people using various versions of the dual hook latch to provide a partially open canopy for ground ventilation. The height of the ground latch seems to vary, often limited by the size angle people can find. These guys seem to offer a super tall option, but somewhat pricey. https://www.airward.com/collections/son ... nditioning

How far do you need to hold the canopy open to get sufficient airflow? It wouldn't seem like you'd need much, and probably not as much at the one listed above.

Anyone else have a different solution to the ground ventilation problem? I have one of Peter's latches to install, so likely I'll do all this at once. I'm sort of leaning toward welding an extension to the current hook.

Thanks,
Rusty

[karmarepair]

The Sonex I flew in Arizona this April had a double latch, and the extra notch opened the canopy about 2-3 inches, which seemed like enough when the plane was moving. It was a sunny day, in the low 80s?

I'm a better fabricator by far than I am a welder. And the offered price from Airward seems reasonable to me.

[13brv3]

Thanks for the comments. The way the windscreen slopes, it would seem like a lot of air would get channeled into a small opening at the front of the canopy, so it's hard to imagine you'd need that 5" open position of the Airward unit. Of course you could just cut off the last notch, or just ignore it I suppose. I'm not the best welder, but I don't let that stop me :-)

It seems like there should be some other option for a prop rod, or other hold-open device. Just curious if anyone used something different from the somewhat normal dual hook?

Rusty

[Onex107]

I just added a second notch below the original one using the aluminum welding rod sold in the fly market. The guy demonstrates it by welding alum. cans. Use a propane torch and don't put the rod in the flame. Just heat the "V" groove until the rod melts when it touches. Plenty of air.

[13brv3]

I just added a second notch below the original one using the aluminum welding rod sold in the fly market. The guy demonstrates it by welding alum. cans. Use a propane torch and don't put the rod in the flame. Just heat the "V" groove until the rod melts when it touches. Plenty of air.

How tall is the second notch, and how well does it work?

I've seen some impressive demonstrations with the aluminum brazing rods, and I probably even have some. Since I also have a TIG welder, that would be my first choice. Just adding the second notch for ground use wouldn't be all that critical, so the attachment method probably isn't all that critical.

Rusty

[Onex107]

The second addition is about the same size as the first one. You don't need much of an opening. The prop blast provides the air flow.

[13brv3]

Since I had a couple days of non-flying weather, I brought the hook home yesterday after making some measurements. I figured 2.5"-3" should be more than enough, and I just finished welding it. I'll clean it up a bit, then take it tomorrow with Peter's latch, and figure out what additional mods are needed before painting. I know the hook angle has to be cut off some in the front to clear the latch block, and the latch block has to be tapered a bit. By Thursday I expect to have the new latch and ground cooling option ready for testing.

Cheers,
Rusty

[13brv3]

I ended up making my ground notch 3" tall, which gives plenty of airflow in taxi. It could probably have been 2"-2.5"and still worked well, but we'll see if I still think that when it gets to be 100 deg in the summer.

Rusty