Cowl supports

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Cowl supports

Postby Mapleflt » Wed Jan 03, 2018 10:48 pm

To all,

I find myself wondering if anyone has ever "cooked up" a cowl support arm of any sort instead of just laying the open cowl over the top while checking oil levels and other associated pre-flight tasks ?

Cheers,

Mapleflt
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Re: Cowl supports

Postby Bruce Fenstermacher » Wed Jan 03, 2018 11:52 pm

You have a '52 and we assume the factory cowling. Always good to mention what you have cause there are two major cowl differences.

The factory '52 opens half the cowl at a time with the open cowl able to fold back on the closed half. The doors tend to be flimsy (bendy, not stiff) and make a great sail. I'm not telling you anything I'm sure. I've never seen anyone rig a support on these cowls or in fact even the later cowl. On the '52 and prior, usually the down wind cowl will be held open with the wind but the upwind cowl will be blown closed. If I need to keep the upwind cowl open I've wired it open with safety wire. But most times I just hold it. I'm thinking if you rigged a support, if you didn't reinforce the entire cowl door, the door would just bend at the point of the support.
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Re: Cowl supports

Postby Mapleflt » Thu Jan 04, 2018 12:48 am

Yes that's exactly my dilemma and its even more awkward for the 5-6 months when I'm on floats !!!
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Re: Cowl supports

Postby bagarre » Thu Jan 04, 2018 1:12 am

We should get in the phone at some point :)

I need to rebuild my cowling and I want to figure out a way to stiffen the barn doors.
My idea was to add formed stiffeners to hold it's shape as well as a way to hold is open vs flipping it over to the other side.
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Re: Cowl supports

Postby Bruce Fenstermacher » Thu Jan 04, 2018 1:35 am

I could see why it would be a special pain while on floats. I'd think the first thing I'd try is a soft quick C-clamp or two like this:
one-handed-mini-bar-clamps-82.jpg
one-handed-mini-bar-clamps-82.jpg (9.65 KiB) Viewed 1857 times


On the upwind side to keep the cowl open against the wind open the door back against the center section. Clamp it there. One issue would be, will this C-clamp fixed arm fit between the cowl and the top inner baffle? I'd think toward the rear and not in the front'.

This 5" deep C-clamp available at Harbor Freight for $5 wouldn't be a one handed deal but it the fixed leg is thinner and the deeper C would allow the clamping action to have a deeper grip and better mechanical advantage:
image_16866.jpg
image_16866.jpg (16.21 KiB) Viewed 1857 times


I've not tried any of these clamps. Just offering an idea one might try that could be installed from one side of the AC. A 10 lb shot bag laid on the open cowl might be as effective in lighter winds.
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Re: Cowl supports

Postby Mapleflt » Thu Jan 04, 2018 1:44 am

I'm envisioning a 90 degree extrusion running full length of the cowl, below the horizontal cylinder baffles with a support arm that hinges off of it and positions into a strategically placed location
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Re: Cowl supports

Postby bagarre » Thu Jan 04, 2018 1:45 am

Im sure i can figure out something better than that
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Re: Cowl supports

Postby Mapleflt » Thu Jan 04, 2018 2:05 am

Let's give it a good, the 170 floats pilots of the world will bow down at your knees kind sir
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Re: Cowl supports

Postby Mapleflt » Thu Jan 04, 2018 2:09 am

Let's STC this and make our fortune !!!!
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Re: Cowl supports

Postby Bruce Fenstermacher » Thu Jan 04, 2018 2:29 am

Mapleflt wrote:I'm envisioning a 90 degree extrusion running full length of the cowl, below the horizontal cylinder baffles with a support arm that hinges off of it and positions into a strategically placed location


I don't see your vision to understand your idea.

The C-clamp idea is simple. There are no modifications of the aircraft. Of course it may not work.

There might be something better and it could even be simple but it would be harder to be any more simple than a C-clamp and no other mods. Lots of times we tend to over complicate things. I fall pray to this all the time.

Of course the C-clamp would need to float since you will drop it in the water. And then you'll need a method, such as a fishing rod with a large hook to retrieve it. :?
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Re: Cowl supports

Postby Mapleflt » Thu Jan 04, 2018 2:42 am

I usually try to go swimming when I want to, not when I have to !!!!
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Re: Cowl supports

Postby n2582d » Thu Jan 04, 2018 7:23 am

Here's how Cessna did it on the L-19:
images.jpeg
images.jpeg (8.01 KiB) Viewed 1834 times
3134.jpg
Figure 26 of the L-19 IPC shows the arm. Air Repair would be the folks to talk to about this.

The H-295 Helio Courier had similar upper cowl doors.
HelioCourier.jpg
IMG_8908m_800.jpg
In the pictures you can make out the stiffeners which made the doors a lot less flimsy than the C-170 cowl. If I recall correctly they had a winged quarter-turn dzus faster to secure the end of the arm.
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Re: Cowl supports

Postby Bruce Fenstermacher » Thu Jan 04, 2018 12:59 pm

Gary strikes again.

IMO Gary, you have an uncanny ability to join a conversation with a fresh look how someone else (usually Cessna) engineered a thing-a-ma-bob to over come a situation. Many times you even have a SB to cover it so one doesn't have to squint so hard to make it legal.

Nice job Gary.

I'm still going to test my C-clamp idea after it warms up a bit here. I just have a passion for pursuing something till I've wasted more time and money than it would have taken to use the established mouse trap. Rube Goldberg is one of my heros. :roll:
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Re: Cowl supports

Postby n2582d » Thu Jan 04, 2018 4:23 pm

Thanks Bruce! I'm with you on reinventing the wheel. There's a real sense of satisfaction on figuring out and completing a challenging project. Of course that comes after pulling my hair out in the process of getting to that often elusive satisfaction. :lol:

Now wouldn't a pair of Door Steward struts be the cat's meow to hold up the cowling doors? Why use a simple rod when you can use a pneumatic strut that weighs twice as much, will be flat in two years, and will require cowl door stiffeners to work? :wink: Here 'ya go!

If you didn't care about drilling holes in your cowl, for less than $4.00 and a couple of ounces, here's a "KISS" solution.
25010_300x225_a.jpg
25010_300x225_a.jpg (25.52 KiB) Viewed 1808 times
Put a hole at the front and the back of each door tangent to the point they touch when the doors are up. Add a doubler around each hole. Of course you now need to install steps on your boot cowl to reach up there ... augh. :lol:
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Re: Cowl supports

Postby Bruce Fenstermacher » Thu Jan 04, 2018 6:30 pm

n2582d wrote:Thanks Bruce! I'm with you on reinventing the wheel. There's a real sense of satisfaction on figuring out and completing a challenging project. Of course that comes after pulling my hair out in the process of getting to that often elusive satisfaction. :lol:

Now wouldn't a pair of Door Steward struts be the cat's meow to hold up the cowling doors? Why use a simple rod when you can use a pneumatic strut that weighs twice as much, will be flat in two years, and will require cowl door stiffeners to work? :wink: Here 'ya go!

If you didn't care about drilling holes in your cowl, for less than $4.00 and a couple of ounces, here's a "KISS" solution.
25010_300x225_a.jpg
Put a hole at the front and the back of each door tangent to the point they touch when the doors are up. Add a doubler around each hole. Of course you now need to install steps on your boot cowl to reach up there ... augh. :lol:


Gary, you missed the added requirement that the door be able to be held open when accessed from one side cause the airplane is on floats.
CAUTION - My forum posts may be worth what you paid for them!

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