40% SD Yak Quandry...

[Mark Davis]

I had an incident with my 40% AM/TOC/TOC EXTREME/SD/TT Yak and the result is that I need to locate a cowl for it... I was able to locate one at TroyBuilt and got Jim to ship it to me... When I tried to fit it to the airframe, it was a little over 1" too small in diameter... Further searching for the proper cowl came up fruitless, until I posted on the SD / TT buyout thread here on FG... Another board member was kind enough to ship me a spare 40% cowl he had that was damaged in shipping to him... Damaged or not, it's better than nothing... Thanks Donnie... Well, that cowl is also about 1" too small in diameter...

The question is: just how many different physical sizes of 40% Yak did the company formerly known as SD actually build???

Any ideas???

[rdgood]

Hummmmm,

Having seen both the 37.5 and 40% cowls, I wonder if Troy Built mistakenly sent a you a 37.5 instead of as 40% cowl??

Here's another thought - I do know that the 37.5% cowl came in 2 different sizes. The first generation cowl was too tight for DA-150 and you had open up the cowl to accomodate the spark plug cap. The newer versions were sort of expanded going out (kinda like a mushroom) for the 37.5% to make room for the DA-150 spark plug caps. So what I am thinking is the mushroom one may be the one you presently have instead of the 40%er??


Ronster

[Mark Davis]

That's what I was thinking... That was until a second person sent me another 40% cowl that was also too small... Now I'm really confused...

[flying skunks]

The cowl was way to large for the 37.5%.You could place the 37.5% cowl inside the 40% cowl.I don't know at this point,could there have been a design change in the diameter of the plane's obver the progression of timelime? (diet)
Donnie

[rdgood]

Have you tried to talk to Troy Built about this? - Gene's always been pretty easy to talk to???



Ronster

[Mark Davis]

Yeah, I've talked with Jim about it at length... He is checking with the factory to see if there was a design change at some point... This is the red/white/2 blues color scheme, which BTW, is no longer available... Just thought someone else might have some insight...

The two new cowls I have will fit inside the one that came off the airplane...

[MikeC3D]

Is the original so damaged that you cant make a plug from it and make a new one? Sorry I dont have a spare, although I do have a NIB ARC you might could talk me out of.

[Mark Davis]

I thought about that, but the front of the original cowl is pretty much gone... No shape there to duplicate for making a plug...

I'm going to take the cowl Donnie sent me and make it work... I'll cut the cowl front to back, section it, increase the diameter to what is required, glass it back together, sand, prime & paint... Much quicker & easier than make a plug, pulling a mold and then laying up a new cowl...