Door Questions

[tswanson_44]

Hi all, hoping some of you can share some guidance. I?m at the point where I?m ready to start building (bubble) doors on an S7 STi.

Is there a reason I can?t install the wings as soon as it?s convenient and then build the doors with the wings installed? Looks like I need to have the wings on to finish the hinge work anyway. I?m not sure when I?ll have enough help to install the wings, so this would give me some schedule flexibility if I can just install the wings anytime I can find help.

Also, how uniform did you get your door frame to door gap (radially) when massaging the door frame? Any gotchas here? The only one I can think of is making sure there is enough room (leave extra clearance) at the bottom/rear for the stainless steel door channels after covering. I?m going with the dual pin door latches if that matters.

is it helpful to have the doors built with a tiny bit of outward bulge at the place where the door latch pins engage so that when the door is pulled shut with some pressure and the door deflects, it will then be (dual) planar with the fuselage door frame? I might be overthinking that a bit but I?ve been around a lot of leaky doors in my day and would like to aim towards the best sealing doors possible.

Thanks in advance!

[n85ae]

Not sure what your latch configuration is, but for sure if you don't have a latch at the front corner of the doors, the airflow
over the curvature of the door will pull them open. As well opening them in flight can be an exercise with a Gorilla, so as far as I'm
concerned opening then while in-flight is off limits. I do fly with them open, but I open them on the ground first. The better option
for doors open on my plane is to simply unbolt and remove the doors. Since the bubble part of the door presses too hard into the
false ribs and I'm not happy with that either.

All that said, I get a fear of heights with the doors off, which I'm not sure why happens, but sitting with my butt on the edge of
a cliff just makes me feel insecure

Maybe some people open and close them in flight, but my experience trying it was exciting, and dangerous - So I don't.

Jeff

[jiott]

I don't see any reason not to install the wings, other than it is somewhat more convenient to work on the upper door hinges without the wings in the way. Also, I believe you can finish the hinge work without the wings on. When you locate the hinges on that upper frame tab, make sure you do it with a piece of the door gasket under the plexiglass for proper hinge location, other wise the finished door will squeeze the gasket too tight when closed.

I used small blocks of wood (balsa) hot glued around the door frame opening to get consistent spacing when tweaking the door frame.

I don't see how you can "bulge" the door at the latch pin area without actually heating and deforming the acrylic. Not necessary in my opinion.

[jiott]

Jeff says his doors press into the wing false ribs when open. You definitely don't want that to happen, because the vibration even when you are idling or taxiing with the doors open will scratch/wear an ugly spot on your clear acrylic doors (ask me how I know). Set the gas spring up so that you have nearly 1" clearance when the door is open. I had only about 1/4" clearance and it was not enough; the vibration and slipstream from the idling prop will cause the door to move up and down more than 1/4".

[n85ae]

I previously machined my lift struts 1" short, so they stopped shy of the wing. This causes another problem that they flex and bend a lot if you ever fly with them open.
I have also tried steel cable leash's, nothing works well to keep the doors getting beat up if open. I think the Bubble doors just do not work well open because the curvature
is basically an airfoil and it creates a lot of lift. The pressing into the wing is the best alternative, BUT the acrylic is going to get a scuff mark unless you have a padded stop.

If you have the short struts, and want to scare yourself, fly with the bubble doors open and the door in free air below the wing ... You'll be convinced the doors are going to
blow into pieces. It's not a good situation.

It might be on a different plane, none of my experience applies ... I have a 74" Sensenich prop and an IO-240B. It pounds the air pretty hard, and might be aggravating the buffeting.

Jeff says his doors press into the wing false ribs when open. You definitely don't want that to happen, because the vibration even when you are idling or taxiing with the doors open will scratch/wear an ugly spot on your clear acrylic doors (ask me how I know). Set the gas spring up so that you have nearly 1" clearance when the door is open. I had only about 1/4" clearance and it was not enough; the vibration and slipstream from the idling prop will cause the door to move up and down more than 1/4".

[Dave S]

Also, how uniform did you get your door frame to door gap (radially) when massaging the door frame? Any gotchas here? The only one I can think of is making sure there is enough room (leave extra clearance) at the bottom/rear for the stainless steel door channels after covering. I?m going with the dual pin door latches if that matters.

Todd,

I have the dual latch pins and am very happy with them. I do not have the current stainless steel caps used for the door bottom (early S7), however the lower side channel is bonded to the side of the fuselage tubing so some space is taken up by that, then the fabric formed over that. Regarding the door gap, the instructions should provide some help with adjusting the door gap. The current assembly may be different than mine; however, mine used shims to adjust the pin brackets for door gap front and back and that worked out just fine. A person can also file the contact side of the pinis necessary.

Cheers,