cockpit coaming how to Fokker DVII

[buck toenges]

I haven't had much success in finding info on making and stitching the cockpit coming to the DVII cockpit. Saw something on this forum about the Rinaldi camel site but couldn't find the site. Is there any how to or pics out there?

Were there grommets on the leather? I read that the german's used fake leather. How far was the spacing for the holes around the turtle deck? I assume the coaming was in 2 pieces due to the metal covering in the front half of the DVII cockpit.

Thanks,
Buck

[vongrube]

Actually I had the same difficulty in finding info on that subject. Finally managed to find instructions in an old maintenance manual. Think it was written back in the 20s or 30s.
There are several ways to do the coaming. All depends on which country, manufacture, and whatever was in vogue at the time.

[Dogtail2]

The Sands DrI drawings explain how to do it.

[vongrube]

Yes I remember that now. But it didn't seem too sturdy with just foam and leather wrapped around sheet metal and stitched. I imagined with the constant abuse the coaming takes that the sheet metal soon would cut through. What I did was run a 1/4 steel tube around the cockpit opening welded to the turtledeck hoop and the top longerons. Then I slipped a hard rubber hose over that. Over that I slipped pipe insulation foam. Finally I encased it all in leather and stitched to the cockpit sheet metal. It is very durable with NO tendancy to tear through. It takes a lot of abuse from me and is very strong. Plus it looks great! :D

[Maxim08]

Hi Buck,

You are correct in that the padding is in as many sections as the coaming. The aft portion is actually nailed with small tacks spaced approximately 3 cm apart. The forward portions are laced from the inside so no visible lacing on the exterior. The forward padding is very thick and wide whereas the portion attached to the turtledeck is more what you would expect to see.

I believe that the material is a synthetic of rubber impregnated cloth and textured, similar to Rexine as used by the British. The closest current material that I have found is Naugahyde which has many similar characteristics; doesn't crack in the cold, impervious to oil etc. All good things at 15,000 + feet in February. On the other hand, most builders like leather and won't be overflying Flanders at -30C.

The forward portion of the D VII turtledeck, which extends halfway up the cockpit, is a 7mm thick lamination. This is where you should be supporting body weight with your hands, not on the forward sheet metal. Just like getting into a single seat racecar. Due to the thickness of the wood, no fear of cutting through the padding.

I hope that this helps a little.

Regards
John

[buck toenges]

Hi Buck,

You are correct in that the padding is in as many sections as the coaming. The aft portion is actually nailed with small tacks spaced approximately 3 cm apart.
Is the turtle deck sandwiched between the top and bottom of the coaming? Are there tacks from the top and the bottom of the turtle deck holding the coaming in place or does the coaming lay on the top edge of the turtle deck?
The forward portions are laced from the inside so no visible lacing on the exterior.
How is this done? Is the aluminum sandwiched between the top and bottom of the coaming? How is the top of the coaming laced so you can not see the laces?

The forward padding is very thick and wide whereas the portion attached to the turtledeck is more what you would expect to see.

Regards
John

Thanks,
Buck

[Dogtail2]

Yes I remember that now. But it didn't seem too sturdy with just foam and leather wrapped around sheet metal and stitched. I imagined with the constant abuse the coaming takes that the sheet metal soon would cut through. What I did was run a 1/4 steel tube around the cockpit opening welded to the turtledeck hoop and the top longerons. Then I slipped a hard rubber hose over that. Over that I slipped pipe insulation foam. Finally I encased it all in leather and stitched to the cockpit sheet metal. It is very durable with NO tendancy to tear through. It takes a lot of abuse from me and is very strong. Plus it looks great! :D

Most of the abuse is to the rear part of the coaming & this is birch ply, not sheet metal. This portion is unpadded on my aircraft as per original. After about 70hrs & 3 years flying it looks the same as when I put it on. The front part is padded with horse hair and stitched as per Sands drawing, and is as good as new.

http://img526.imageshack.us/img526/5847/img0945i.jpg

[vongrube]

1/16th ply to be exact. Yes I know. I was talking about the forward sheet metal portion where the hands are placed the most while getting in, and out of the airplane. Why would the aft portion of the cockpit coaming get the most abuse? Unless you are sitting on it constantly? I cant see how that would be good for the 1/16th plywood. Of course they really didn't expect the planes to last too long anyway in those days did they?

[Maxim08]

Hi vongrube, don't want to be pedantic but I was reasonably sure that I explained this in my previous post, last paragraph.

I don't know what Ron Sands used as source material for his drawings but since there are, apparently, no original Dr.Is around I would bet that there is some guess work here. Since the D VII followed the Dr.I pretty closely, it would seem reasonable that a lot of design practices would be similar. Since existing D VIIs do not have welded steel tubular hoops around the cockpit coaming as shown on Sand's drawing 'Sheet 17', I would bet that this is an 'update' on not based on any research findings.

The rearward use of your arms to lift yourself in and out of the seat is not intuitive to most people but very effective although you may need to work on those muscle groups. I know that I certainly don't get in and out of formula cars with the same ease I showed 40 (gulp) years ago.

Build your turtledeck in a similar fashion to a D VII and I bet you'll save some weight in the fuselage.

Regards
John

[buck toenges]

I guess I need to get the Sand's prints to see how the coaming is connected to the plane. The pic of the DRI looks like there is stitching under the turtle deck holding the coaming in place. There also looks like a nail attaching the coaming.

How do i get a copy of the sands drawing for the coaming?

Thanks,
Buck

[buck toenges]

Most of the abuse is to the rear part of the coaming & this is birch ply, not sheet metal. This portion is unpadded on my aircraft as per original. After about 70hrs & 3 years flying it looks the same as when I put it on. The front part is padded with horse hair and stitched as per Sands drawing, and is as good as new.

http://img526.imageshack.us/img526/5847/img0945i.jpg

I got the sands drawings but am still confused how the stitching works. The rear section coaming looks like it is folded under itself on the top of the turtle deck and then it is stitched underneath the turtle deck. If the spacing of the holes is about 30mm what tool do you use to thread the cord through the turtle deck? It also looks like the coaming is tacked to the turtle deck before the "leather" is wraped over the turtle deck. Is the coaming glued down?

Can anybody explain?

[Dogtail2]

Buck,

The sheet metal and ply are pre-drilled to accept needle and thread at suitable spacing. The leather is placed outer side against the metal/ply and stitched along the whole length of the piece at the top edge. The leather is then folded over itself to the inside of the cockpit so that the outer surface of the leather is now to the outside. It is then stitched on the inside of the cockpit by passing the thread through the threads made earlier which can be seen inside the cockpit. Stuff the front portion with the filling from one end. I used horse hair. Close off the end through which the stuffing is added. The rear coaming is done the same way but not stuffed. I used no nails. What looks like a nail in the rear part in the photo is actually a small fly.

That's the best I can describe it at the moment being away from home.
Good luck!

[Dart]

Good grief, I understood that completely! Basically they made the combing on one side over a form and then attached it to the fuselage by stitching through the exposed stitches on the bottom of the other side.

So the outside edge of the combing is wrapped around the form and back to the inside of the cockpit, and the inside of the cockpit is wrapped from the "loose" end and then stitched up into the loops of the cord.

That also makes repair a heckuvalot easier - undo the stitches from the fuselage, lift off the combing, unstitch/unfold if required, repair, re-fold, restitch.

It also serves to reinforce around the cockpit edge.

Nobody can say those guys back then were dummies.

[SCMc]

...
The rearward use of your arms to lift yourself in and out of the seat is not intuitive to most people but very effective although you may need to work on those muscle groups. I know that I certainly don't get in and out of formula cars with the same ease I showed 40 (gulp) years ago.
...

Regards
John

Just by coincidence, following a link Froggy posted, I came across a GIF of Voss starting to get out of his DR.I here (http://derrotekampfflieger.tumblr.com/page/13). As John suggested, he is reaching back to the turtledeck.

Steve