NOS Cowling

[Mark Julicher]

Here are some fit-up photos of putting on a NOS cowling. This was a relatively new cowl made of 2024 aluminum vs the old 3003.
This is in roughly chronological order showing some of the test fitting and Dzus fastener installation.

[Mark Julicher]

Re: NOS Cowling

More cowling fit-up.

[Mark Julicher]

Re: NOS Cowling

Next batch of cowl photos. We (mostly) used the plastic Dzus retaining grommets because they allow a slight bit of adjustment for less than perfect holes and because you don't need the special tools to use them. These Dzus studs are AJ40 and AF45 with fairly tall springs. The plastic retainers allow you to try and re-fit without a lot of difficulty removing a Dzus stud fully set in a metal grommet. The plastic can be changed out for metal later if desired.

[Carrieve]

Re: NOS Cowling

Makes me want to go out and buy new to replace the dinged and bent one on my old girl. Very nice job.

[bashibazouk]

Re: NOS Cowling

Beautiful! So Mark, is that a one-piece top cowl? Is there a hinge there I can't see in the photo? Also, not sure if I'm looking at the photo right, but the bottom piece has flush rivets and a strip backing the main part of the cowl instead of a joggle in the cowl material? If so, that makes more sense than trying to get the joggle in the 2024 and it's a neater fit, too. Is that .025 or .032 2024? Looks like you can get away from all of those nasty folded edges with the 2024, too. Sorry for all the questions-- I'm in dire need of a similar rework.

It looks great!

Josh

[Mark Julicher]

Re: NOS Cowling

Josh,
I never measured the cowl pieces, but they feel like .032 with the doubler made of .025. Let me say that I have been handling these cowl pieces as though they were made of pure unobtanium. We measure five times and still cringe when we have to make a cut or a hole. I wish these were 3003 aluminum though, because I could weld up a mistake and I could easily anneal a few places, but I'm not being too critical, it is great to have these. It will be a lot of pounding and fussing when I start repairing Doc's old cowlings.

Doc's original cowling had the edges rolled and bent as you describe, but my own cowling and Doc's NOS cowling use a doubler at the top edge of the lower cowling. I looked at what it would tale to make the older style bends and it would be a bit of work with a large brake. Yes there are flush rivets to attach the doubler and it works very well. Today I will mount the draw bolt latches to complete the job and begin to paint.

There is a brand new slip hinge in the center of the top cowl doors.

The air scoop fits nicely over the Brackett air filter, but it is not a scoop design I have seen on any other Taylorcraft. The scoop is certainly easier to make than the older stamped version and it appears that it will be stiff enough to work well.

Interestingly enough, Doc's old nose bowl was from a Deluxe. The grill wings do not match the curve on this new nose bowl. We are pondering how to make them fit, but I doubt if it can be done safely.

The doublers at the lower corners of the bottom cowl are home brew design. I have never had a cowling crack with my steel doublers, but my originals were prone to causing stress cracks. Just use care that the rivets don't interfere with the lower boot cowl. The exhaust cut out was not correct and we had to enlarge it slightly too.

The biggest PITA was lining up the holes for the Dzus fasteners. There is not much forgiveness for misalignment, so it was a lot of fit-cut-fit-cut-fit...

[N95334]

Re: NOS Cowling

Hate to ask a stupid question. Why is it called a NOS Cowling?

[mhorowit]

Re: NOS Cowling

Hate to ask a stupid question. Why is it called a NOS Cowling?

New Old Stock.
I think it means it was produced by the factory and never taken out of the wrapper - Mike

[Pearson]

Re: NOS Cowling

When you write the check for it, you will think it stands for Never On Sale!

[Mark Julicher]

Re: NOS Cowling

Completed but for paint...

[bashibazouk]

Re: NOS Cowling

Mark,

is there a trick for lining up the holes for the dzus fastener holes with the existing holes in the nosebowl and boot cowling?

Thanks,

Josh

[Mark Julicher]

Re: NOS Cowling

Josh,

The main trick is patience, but I'm not sure what you are asking. Do you already have holes that just don't want to line up? Or are you fitting new parts that are undrilled? Some nuances to deal with, but here are a few things I learned along the way:

It is best to have your chafe strip installed before measuring for where the holes go. The extra thickness can change the hole alignment about 3/16 inch.

It is really good to line up ONE hole on each side of the aft part of the lower cowl, drill and set Dzus fasteners and THEN go on to the next hole, drill and set fasteners, etc. If you try to do all six aft holes all at once it is too easy to accumulate errors and miss-drill a hole.

I made a hole finder that works just like a rivet hole finder, except I had a ground-down number 5 stud on the probe end instead of a 1/8 rivet.

IF YOU ARE OFF JUST A LITTLE... Don't sweat it! Use the plastic Dzus grommets to hold in any fasteners that are off just a tad. The plastic grommets allow about 3/32 of movement in the stud and you have a slightly adjustable installment. If you use the full metal Dzus grommets you don't have any wiggle, although the full grommets give a better wearing surface for the stud - it is a trade-off.

Studs AND springs come in different lengths/heights. It is good to have an assortment on hand. My cowl is all done with AJ5-35, but we needed some 40s and 45s for Doc because of different spring heights and such.

Hope that helps.

[bashibazouk]

Re: NOS Cowling

Thanks, Mark.

Apologies for the vague question.

Yup, I'm trying to figure out how to make a new cowl to replace my old, cracked one. The challenge of lining up the new dzus grommet holes on the cowl pieces with the existing springs/holes on the boot cowl and the nose bowl.

The idea of using an old fastener modified to mark the back side of the cowl pieces makes lots of sense. Also, the idea of doing one at a time is a logical decision-- sort of like using clecos. Thanks for the heads up re: the chafe strip, too!!

Josh

PS. Nice spark plug cups, BTW!! That cowl is gorgeous. Nice and tight and no bumps!!

[jack]

Re: NOS Cowling

Who makes them?

[crispy critter]

Re: NOS Cowling

I agree pretty much with everything Mark said except using the chaffing tape when fitting and marking. I did that once on a cowl and it was easy to install right from the start. However after the chafe tape seated in after a while the cowl started to open up some very small,very noticable gaps especially around the nose bowl. I used 2 layers of good quality 3M masking tape in place of where the chafe tape goes. The 3M gives you protection from scratch's,the double layer of 3M is about half the thickness of new chafe tape(almost as thick as it will be once it seats in) . After your holes are drilled and everything is fitted and finished then you will put your chafe tape in place and I will admitt that lining up your holes the first time or two will probably take someone to help because that are a little touch. However once everything gets seated in you will be please with the final fit.