Seaplane doors: bottom door frame buildup

[whee]

I'm starting to build my seaplane doors. You guys that built them did you curve the front lower section of the door and does it allow the door to sit flat enough against the wing to fly with it open?

I think the door has to be curved to look good but I'm concern that it won't sit against the wing good enough to fly with it open.

[JCD23]

So has the verdict been issued on flying with gull wing doors open in flight?

[marcusofcotton]

I've considering various ideas, including seaplane doors that may curve out. While at OSH this year, I specifically inquired of a few owners of other planes that had such and how they worked out for flying while open. Each said surprisingly well and stable. All were low speed aircraft, Kitfox etc. I'm still a little pessimistic though.

[rodsmith]

I recently decided to build seaplane doors. I wasn't sure what the best way to build up the door sill was until I saw a post by Nev where he used wood. I found a piece of 4x4" balsa on ebay. Ripped it in half and used my brother-n-laws planer to make 1 3/4" boards. Fortunately I had taken measurements when I had the wings on so know that this gives me clearance with a 3/8 door overlap. I used some 3/16" machine screws from Ace and large washers to attach the balsa to the steel door formers. Covered with fabric and made a sill cover with 3 layers of carbon. The issue I have now is that I had an extension of the boot cowl that now is not high enough. Haven't found a solution to that, definitely do not want to redo the boot cowl. Waiting on a few more parts to start on the carbon tube frames for the doors. Composite rear passenger and baggage doors are complete except for finishing.

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[svyolo]

You could make a cosmetic cover for the door sill all the way down to the now too short boot cowl extension.

[Nev]

That’s a great solution. Very much looking forward to seeing how your carbon tube framed doors go. I really think that’s the best way to go.

[svyolo]

I will for sure make composite cargo doors after my project is flying. The front doors, I thought I would but had serious second thoughts. I calculated out the weight savings for carbon and aluminum square tube. Carbon is a bit lighter per foot, but each intersection of tubes is going to add weight as you have to reinforce the joint, and spread the load down both directions of the intersection. That is going to cut into the weight savings over welded square aluminum tube. The cost of CF square tube is pretty high. Ultimately, most of the weight of an all glass door is......the glass.

My aluminum welding is still sub par. Working on it. This morning I made 3 thin wall SS blast tubes. AL would have been slightly lighter, but my ability to weld .016 SS far exceeds my ability to weld thin aluminum.

[alaskabearhawk]

Rob Taylor did something similar, but used fir for durability and capped it with SS.

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[svyolo]

BTW it looks like lots of folks want seaplane doors, and lighter doors. Might be a good opportunity to sell some parts. I would buy them. And better wingtips

[LukeFrog]

After visiting Simon and chatting over his build this past weekend we were wondering if, with the changes in the B-model components, it's still necessary to raise the sills for a seaplane door to clear the strut? Can anyone confirm this?

Also agree this would be a great kit option

[robcaldwell]

I did on mine. Seems to be a prudent mod.

[Nev]

I raised mine 2 inches (copied Rob) and this worked well. You could probably get away with not raising the sill on the B model, but it'd be very close.

[Nev]

Has anyone tried to open a seaplane style door in-flight ? Or had one come open by accident?

Mine have a single gas strut at the aft of each door. They're not stable enough to be opened with the engine running, so I'm adding an extra strut to the front of each door which I think will make them much more stable. I want to be able to have them open when taxying in hot weather. They don't need to be opened in-flight, but I wouldn't mind knowing what might happen if one was opened accidentally. One of those things.....if it can happen, then it probably will.

[Gary Wallace]

I have seaplane doors. Single gas strut at front. I always open door(s) when it is hot for taxi. Mine did open once accidentally while flying. Surprisingly with no ill effects. I did close it quickly, and have not tried flying with it open since. It's windy out there!!

[Nev]

Someone asked me recently whether it's possible to build seaplane doors without raising the lower door sill. On mine I raised the door sill during the build by 50mm thinking it was needed to clear the strut however it appears that on the B model this is not necessary. I measured my plane and Simons, and both have the clearance needed between the lower door and the wing strut when partially open. The picture below shows 52mm (2") clearance with the overlapping door skin.

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[Richard E]

Nev. I measured our standard B model ZK-RJE yesterday. The actual opening size would just, just allow a seaplane door to open past the strut. However the flange making the door weatherproof would not fit. So some slight adjustment of the sill would be necessary to raise it say 10mm, but only at its lowest point. NZCAA could require some sort of extra restraint to fly with the door open as the seat level is above the opening. Also a deflector to stop your hair being blown out of place!

[Nev]

Good to know Richard and hopefully of use to those considering Seaplane style doors in the future. If I was to do it again I'd probably leave the door sill as it was and just make adjustments to the door itself.

[rodsmith]

I built seaplane doors for my pre B model 4-place. I raised the door sill 1.75" based on measurements taken when I had the wings on. Then I worried that that wasn't enough, hearing how much others had raised the sill. When I finally got the wings back on I was relieved to find I had plenty of clearance. I would have been OK with 1.25" instead of 1.75". It works out well though as I didn't have to trim the overlapping skin. It wouldn't be possible to use a seaplane door without raising the sill on the original 4-place without making some sort of provision for strut clearance.