The International Cessna^® 170 Association

Recently I have seen 2 different C-150 tail draggers and a Cessna 170B with an aftermarket unit ( aluminum block with a notch and two spring loaded ball bearings on either side of the notch) that is riveted on the top of the door, on the outside surface where the original receptacle hole is located at and the other part is mounted out on the original spring steel clip that engages with teh door mounted part, that makes holding the cabin doors open a very simple, but sturdy set-up. I will try to get a pix of it next time I see one, but my question is where can these be purchased at?

Over the years there have been several people adapt ordinary kitchen cabinet hardware to this purpose. Some of these people marketed their product in a simpler more practical time regulatory wise. Most of these people and their products have come and gone. I don't really know of any still on the market.

Most of the products were simple and stout and they worked well. They were popular over original method of stabbing a hole in the door in which a keeper, if it wasn't broke, would hold the door. So you still see a lot of this hardware on aircraft today and little known to most is these parts are little pieces of unobtainium. At least I've not found any suitable in 12 years of 170 ownership.

Of all methods to hold a door open, the Doos Steward is by far the best. I installed mine last year and love them.
Yo no longer have to worry about them staying open or the wind catching them.
Well worth the money.

Those who have gone to the trouble of the door stewards do like them, but it is not a good idea to believe they may be left unattended with the door open.
A strong wind or prop-blast may not destroy the door steward device itself... but the strain will be placed upon the DOOR HINGES ... and those upper hinges are also made of unobtainium.

Do not leave your cabin doors open and unattended. IMO.

DMACJR wrote:Recently I have seen 2 different C-150 tail draggers and a Cessna 170B with an aftermarket unit ( aluminum block with a notch and two spring loaded ball bearings on either side of the notch) that is riveted on the top of the door, on the outside surface where the original receptacle hole is located at and the other part is mounted out on the original spring steel clip that engages with teh door mounted part, that makes holding the cabin doors open a very simple, but sturdy set-up. I will try to get a pix of it next time I see one, but my question is where can these be purchased at?

Probably 20 years ago I bought and installed units very similar to what you describe called Sky Catch. I saw it in Trade-A-Plane, but haven't seen it in a LONG time. They work very well, holding up to about 15 knots, but not too hard to engage and disengage. Spring compression on the balls is adjustable to suit your needs.
I may have some photos, but I'll have to search for them.

gahorn wrote:Those who have gone to the trouble of the door stewards do like them, but it is not a good idea to believe they may be left unattended with the door open.
A strong wind or prop-blast may not destroy the door steward device itself... but the strain will be placed upon the DOOR HINGES ... and those upper hinges are also made of unobtainium.

Do not leave your cabin doors open and unattended. IMO.

This is true no matter what type of door stop you use. I am totally pleased with Door Stewards.

The damage to the hinges and door come from the door slamming into the stops when the wind catches it.
The steward strut prevents this from happening. the load on the door in a stiff breeze or prop blast is no more than if you were holding the door open with your hand. The chances of damaging the door in this way are diminished to the point that I consider it a negligible risk.

bagarre wrote:The damage to the hinges and door come from the door slamming into the stops when the wind catches it.
The steward strut prevents this from happening. the load on the door in a stiff breeze or prop blast is no more than if you were holding the door open with your hand. The chances of damaging the door in this way are diminished to the point that I consider it a negligible risk.

That's not correct. With the door open the steward provides more support than the hinges can withstand, and an open door is like a huge sail... it will damage the door hinges if the door should be blasted by wind.

I think the damage is done when a door is left to blow open and it bends as it hits the strut stressing the hinges. This is what happens when your partner decides to remove the door stop all together and there is nothing but the strut to stop the door.

Of course if your partner left the door stop on and the door slammed into it, the door would bend on the hinges but in a different direction.

I'd think that if the Door Stewart was not a dampened system, the door being slammed open against it would also twist the door on the hinges. But the Stewart is dampened and I assume it would afford some protection of the door being slammed to any limit this protecting it from that stress.

I don't think there is any system that I would leave a door open unattended.

[quote="gahorn" With the door open the steward provides more support than the hinges can withstand, and an open door is like a huge sail... it will damage the door hinges if the door should be blasted by wind.[/quote]

That makes no sense. There is no difference in the mechanical advantage on the hinges if the door is held open by hand, by a gas strut or if propped against he original wing support. Unless you have a 747 on takeoff behind you, you're hinges are fine. Those hinges will stand up to a hurricane so long as you don't let the door slam open.
The damage to the hinges happens when the door is allowed to be caught by the wind and slams against the stops.

Anyone with a basic understanding of mechanical advantage should know that.

Many yrs ago I too purchased a set of the Sky Catch units that Miles referred to. The last time I searched for them to tell a friend where they might be purchased I was unsuccessful in locating them. I don't believe they are still in production. They work reasonably well (much better than the Cessna system), but aren't foolproof. As Miles mentioned, the tension on the springs, which go against the small balls, can be adjusted. At some point a bit too much tension and the wing mounted portion will not latch between the two balls and if not sufficient tension is applied the door won't remain open. I believe they would work much better on a tricycle geared plane because on tailwheeled planes the doors have more gravity pulling on them and in many cases a bit of wind can cause the latches to let go and the door closes/slams shut.

Some years ago I either did a post or sent George or others a rather crude drawing of a door catch I once observed on a C-180 at Grand Praire, TX airport. The latch may have been an owner produced part, but appeared to be much better than any other door latch I have seen. If anyone is interested I can dig up my drawing and email or snail mail it to you.

Frank

David, ...think about a lever and a fulcrum.
The door steward only partially solves the slamming door problem. It does indeed reduce the possibility of a door slamming against a stop or against a strut.
But... the door steward holds the door down low, and the majority of the door which acts as a sail is outboard of that socket. The door steward now behaves as a fulcrum and stresses the hinges when the large door is blown.
While the steward is better than nothing, it is not better than a door held fully open even by an original door catch... and I don't recommend any door be left open unattended because of that possibility of damage.

I see little difference in the stress on the door held open by a Stewart verses the original stop except the twisting force on the hinges would be opposite because the door is held on the bottom by the Stewart and the top by the original.

I think most damage is done by the slamming door and the resulting twisting action, not the stress of a door held open. And I know a door held open acting like a sail has stress on the hinges but I consider it normal.

I cringe when I see any open door open and unattended and just think it bad practice.

It would appar that to minimize stress on the hinges of the open door, the door would have to be restrained in the approximate vertical center of the rear of the door frame. This just aint gonna happen unless someone just holds it.

Or, use the original door stop AND Door Stewards so the doors are constrained both top and bottom so no leverage or twisting motion, overkill and not really practical. Just hold the door against tailwinds and gently close them after you get out. Problem solved.