Top dust cover (aka top boot) question

[KWTownsend]

Many of you have been following my quest to come up with a top boot that will serve my 1911 touring car. I am designing a pattern and Mike at Classtique will stitch it together for me. My question is about the straps.

It will have three straps. One in the center and the other two about 16" from the center. The center strap is attached to the underside of the cover. It is threaded up between the body and the rear curtain between the Murphy fasteners, then comes through the top side either through an eyelet or a flat "loop" under the front edge of the top of the cover. Then the straps continue down to the seat frame where they will have a snap.

Typically, the two on the sides are attached to the top and those straps continue down to the seat frame.

I am considering having the other two straps follow the same configuration as the center strap. They would only be about 15" from the center to pass by the last fastener of the roll-up portion of the rear curtain, just before top rear 1/4 panel. My thought is that configuration will keep everything bundled up better and help prevent the top boot from "ballooning up".

How much does a top boot “balloon up”?

Would it balloon up less if the top boot is more bundled?

I would appreciate your thoughts and input.
Thanks,

: ^ )

Keith

[Original Smith]

Keith:
Your outer straps need to go out another 2" to look correct.

[KWTownsend]

I agree. If the outer straps were attached to the top of the cover, I would move them out another inch or two.

However, with the top strap configuration that I am asking about (the outer straps attached to the lower part of the cover) the straps need to be close together enough so they can pass between the body and the roll-up curtain at the outer edge of the roll-up curtain. (only about 30")

(This is what was Royce's car, then became John Mayes' car, but is now in Scotland...)

In addition to the two Murphy fasteners on my car, the top rear 1/4 also has a screw between them, so there is no gap for the strap to pass through.

So the question remains...

How much does a top boot balloon up while driving?

Should I have the straps attach to the lower part of the cover, so it is more bundled, or should I have them attached to the top part of the cover and move them farther apart?

Am I being over analytical? I need a wind tunnel...

: ^ )

[RajoRacer]

How fast do you drive, Keith ??????

[Jeff Perkins]

Keith,
I have never had a problem nor have observed any “ballooning” with my dust covers on any open Model T I have had. Last week I just had my runabout drive by my house at about 30 mph, wife taking video. All looked normal, even the driver!

[brucesp]

Keith... FWIW, the top boot on my '15 doesn't balloon at all, even though it seems that it should, given its resemblance a parachute. My guess is that the windshield throws the air up, which then comes down onto the top boot, instead of from straight ahead. All I know is that there's no hint of the boot filling with air. And as you know, I drive plenty fast.

- Bruce

[Erik Johnson]

I would do the opposite of what you are doing regarding where the straps are fastened to the boot.

I would have only the center strap attached to the bottom of the top boot and pass through the rear curtain and through the top of the boot. This pulls up the bottom of the center of the boot which also eliminates sag on the sides giving it nice, tight look.

See this thread where I show the original top boot as well as the reproduced boot my father made that is shown installed on his 1917 touring. Note that he did have to compromise on the straps - the originals are cotton webbing which is hard to find in the correct size so he made the straps from folding over and sewing naugahyde.

http://www.mtfca.com/discus/messages/59 ... 1455820509

[Original Smith]

I believe the center eyelet is the same dimension as the common sense eyelet I think. The only difference is there is not notches. Maybe Mike at Classtique know where to get them.

[KWTownsend]

Thanks for the input. I will plan to have the outer straps attached to the top part of the boot, and will move them out about 2"

I would welcome on construction of the straps. 1" wide?
Should I use the same material as the boot fabric?
I think woven cotton might stretch or shrink.
Maybe woven nylon?
I will use a flat "loop" sewn in place, like in the picture above, instead of an eyelet.

: ^ )

[Original Smith]

The original straps for pre 1915 are leather. I've you wish, I can measure one of my originals. I think they are 5/8".

[TWrenn]

Yeh, I think you're on track keeping the so-called outer two straps attached at the top part of the boot. This will definitely prevent the ballooning you're concerned about. Because without them, it WILL balloon quite a bit. I'm sure that's why they were designed the way they were originally. The center strap, coming up from the bottom, does a nice job of "squeezing" the bottom portion of the boot up to the top, and just makes it look better from behind. Just my thoughts.

And, when did Royce/ John's touring go to Scotland?? Wow! Can't believe John got rid of so quickly after he re-restored it.