Seaplane door hinge

[SimonNicholson]

I have almost finished my door mod and am getting ready to attach to the frame using a piano hinge.

What precautions limitations do I have when drilling into the fuselage? Am I better to drill and tap for machine screws or rivet the hinge? I am concerned that this may be a source of moisture entry into the fuselage.

[jaredyates]

I'll say that I ended up recovering my gear legs because Bob didn't like that I had drilled holes for riveting on acess panels. Can you weld on tabs to hold the hinges, or perhaps add on an extra hinge or two with the usual method instead? I'd be reluctant to put holes in any primary tubes.

[Mark Goldberg]

Jared's advice is correct. It is not good to be drilling into tubing structure. Drilling into a door frame is OK as the door just covers a hole. Mark

[Mark Moyle]

Another option is bushing through the tube... something like this..

[Gerhard Rieger]

Great job, looks good

[SimonNicholson]

It is always no nice to see everyone’s imagination to solve the same problem.

I liked the idea of using a piano hinge as it would help seal up that top gap, but there are other ways of solving that chestnut.

Thanks for the info re not drilling into the fuse. It didn’t seem the right solution.

[Mark Moyle]

Thanks for the info re not drilling into the fuse. It didn’t seem the right solution. [/QUOTE]

That’s why I suggested the bushing. Still drilling through the structure, but is 100% welded to seal up the tube. The other issue is shrinkage. Skip welding a piano hinge will distort the tube a bit. Welding on the side facing out..the tube will bow inwards. Persuade the tube back into alignment... hammer and a coved block of wood....works.

I used 1/8” shims around the perimeter when I fit the 5/8” x 0.035” 4130 square tube. The top door seal is 3/16” thick. The remainder is the ”P” shaped door seal.

[SimonNicholson]

I have decided to supplement the existing window hinges with two additional ones. This will involve welding two 3/16 id tubes on each side. I figure this will be the simplest solution.

[Battson]

I have decided to supplement the existing window hinges with two additional ones. This will involve welding two 3/16 id tubes on each side. I figure this will be the simplest solution.

I think this is a good solution, I think it's going to look the most elegant. I can show you an easy, cheap, and very effective way of sealing that gap. In fact, see my post on winterisation.

The trick of course is getting the hinge line straight, to avoid the hinge bending the door as it opens. Two hinge points is attractive because there's no chance of misalignment or bending.

I would have thought two hinges would be more than strong enough, personally. 4130 is hard. Unless you are planning to open the door in flight?

[SimonNicholson]

I was wanting to have the option to fly with it open. My solution for this is to install the type of mechanism I used in 185/182during skydiving ops. This will give a way of locking the door open and keeping some of the pressure off he hinge.

[Glenn Patterson]

We did the 3/16" ID Tube with 3 pieces per hinge. It would be good to put abut 1/16" spacer behind the barrels on the fuselage so it is easier to put the hing pins in and out. Ours was tight so we had to grind a flat on one side of the head of the pin so it does not grind on the fabric. The hinges work nice and have a very small profile facing in to the win. We used std 3/16 pins and cotter pins on all our door hinges. Could run a 3/16" rod through to get the alignments.

[alaskabearhawk]

I did what Gavin Chester did for my seaplane doors. http://www.mykitlog.com/users/displa...=234413&row=35

[Peter Bishton]

Gents
with the seaplane doors, do they clear the wing lift strut if you build the door into the frame as per the drawings ?
It looks like in the posts above the bottom door sill has not been raised up so it sits on the tube running fore/aft. Would that be correct ?
peter
4 place plans # 1184
australia

[SimonNicholson]

No. With the bottom sill as per the drawings the door would come in contact with the wing strut. I have raised the front half of my door 50mm. Others have done similar.

[Battson]

I was wanting to have the option to fly with it open. My solution for this is to install the type of mechanism I used in 185/182during skydiving ops. This will give a way of locking the door open and keeping some of the pressure off he hinge.

Ever been hit in the head with the lever, when the door unlatches by accident?

I would suggest considering a gas strut, makes the door feel weightless which is nice and feels professional to operate. Also it tucks away without obstructing the cabin as much. Weight is similar to the Cessna style lever I think.