I've got cowl problems...

[cjensen]

First, I knew most of these problems were going to arise in talking with Will James about this cowl (bought second hand after the guy cut it too short, and would not put blisters on this cowl), so none of this is a surprise, but I thought I'd put a post out about it to see if there are any suggestions...

The alternator and starter interfere, so I cut holes for blisters there...not a big deal...





The next hurdle is the exhaust interference. Vetterman says no less than .75 inches clearance...take a look...





Thoughts? Obviously, a hole and blister will need to be made here, but what I'm more concerned about is how it will look on the outside. I don't care about a couple of blisters up front for alternator and starter clearance, but the exhaust could be a show stopper.

Also, I'll have to make some cut and pastes for the FAB down the road as well...

Perhaps I should scrap this and buy a new one...man, that's a lot to swallow. I kind of feel like

[painless]

I know you don't want to hear this, but it looks like it is becoming too much of a chore to make this cowl work. I have a friend that installed a rotary, turbocharged engine in his 7A and the cowl had to have all sorts of lumps and bumps in it to fit, and it looked really cheesy.

Back to the drawing board, and reach for that wallet Chad.....

[bullojm1]

Chad,

I'm sorry to hear about your issues with the SJ cowl. Just as a note, I have the Sam James short cowl with the Vetterman Exhaust, SkyTech lightweight starter and the PlanePower alternator. I have about 3/4" clearance on the alternator, 5/8" on the starter and at the worst spot, 5/8" clearance on the exhaust, which I think I can make better since it is below the ball joint.

I hope all works out for you Chad. If not, chop the fronts off your plenum and send them to me!

[1:1_Scale]

Couldn't you just make one big "blister" and give everything more room? I'm thinking something along the lines of the RV-10 cowling mod here.

[weezbad]

ewwww, chad, that looks a bit rough. but in light of that, i have found that if you just finish it out and wait till later to decide you may find it isnt nearly as bad as you think. if you go at it with the "oh well im probally gonna get another one" then you may as well trash it now.

my hunch is that it will look like components have overheated it and are melting it. you will spend most of you fly in time explaining the bumps. who knows, you may even be branded with some stupid call sign like bumpy or lumpy.

[cjensen]

I'm gonna call Liz in the morning to get on the list for a new one...you're absolutely correct Willy, I don't want to explain all the bumps.

Sorry Mike...my plenum isn't going anywhere!

I just don't want to put a ton of work in to this, and not like it. If I get the long cowl, I know I won't have issues, at least with the alternator, starter, and exhaust. The FAB could be a problem because of the long engine mount, and that will still make for a custom prop spacer because I won't be able to get four inches of space. Probably a 2" custom...

Looks like the emergency airplane credit line has to come open...

Anybody want a cowl REALLY cheap???

[hydroguy2]

Chad, if you need to you can have my place in line. I contacted Liz in May and got on "the list" but told her I was in no hurry since I still need an engine. If it helps you, take my place

B

ps-I've got a few paperweights/doorstops, but nothing as major as a cowling. chock it up as part of the experience.

[cjensen]

Thanks Brian! I'll call Liz this morning to see where you're at on the list for delivery. Now that I'm gonna have to start anew, I really don't need it until the prop is here, which could be February, but no sooner I'm sure (Catto).

Yeah, it's the biggest, most expensive paperweight I have ever seen, and never expected.

[cjensen]

I talked to Will a few moments ago, and he said he could make a custom cowl to fit my unique combo, so I think that's what I'm gonna do. Sucks, but it's better to have it functional and look nice than marginal, and lumpy...

Brian, they are checking on your position for me, and I'll be in touch if it works out.

[Spike]

Call me crazy, but is your alternator belt on inside out?

[cjensen]

Call me crazy, but is your alternator belt on inside out?

CRAZY!

Nope...that's the belt that comes with the Plane Power alternator...has ridges on the outside.

[dons]

Yikes, that looks like it could become a LOT of work Chad.

You certainly don't want to be known as Lumpy or Bumpy, that would likely stick

[cjensen]

Yikes, that looks like it could become a LOT of work Chad.

You certainly don't want to be known as Lumpy or Bumpy, that would likely stick

You got that right!

It's what I get for trying to save money tho...

[DanH]

Chad, you really can reshape that cowl so you don't have bumps. Sure would be a heck of a lot cheaper than a new cowl and prop extension.

Consider a foam core overlay. I did one on an -8A so the builder could use a 14" aluminum spinner. Increasing the cowl nose diameter meant adding 1/2" of foam to the surface, shaping the foam, then a few plies of glass fabric for the new skin. Standard old-time Rutan stuff. In your case, you just scoop out whatever clearance you need on the inside and glass a new inner skin in the surface depressions. Smooth exterior, clearance on the inside.

[TomNativeNewYorker]

Yeah, it's the biggest, most expensive paperweight I have ever seen, and never expected.

I know someone who CREATED a $1,000,000 paper weight mistake.

A QA(supervisor) did a maintenance turn on a T-56 engine with a scribe sitting in the intake prior to start up. He checked the intake and knew it was there but assumed someone was going to remove it.

I was with another crew over 2000 miles away and we got our a$$es chewed out even though we had nothing to do with that particular maintenance evolution.

[cjensen]

Well that makes me feel a little better!

[cjensen]

Chad, you really can reshape that cowl so you don't have bumps. Sure would be a heck of a lot cheaper than a new cowl and prop extension.

Consider a foam core overlay. I did one on an -8A so the builder could use a 14" aluminum spinner. Increasing the cowl nose diameter meant adding 1/2" of foam to the surface, shaping the foam, then a few plies of glass fabric for the new skin. Standard old-time Rutan stuff. In your case, you just scoop out whatever clearance you need on the inside and glass a new inner skin in the surface depressions. Smooth exterior, clearance on the inside.

Cheaper, yes. But I don't want to change the look of the SJ cowl...that's the main reason I want one. I'll need an extension either way anyway...and I'm not a big fiberglass enthusiast...

[1:1_Scale]

I was thinkingalong the same lines as Dan, and I would think that if done properly, most people wouldn't notice. But if you're not hot on working with the FG, I guess it's a moot point

How about ceramic coating the exhaust pipes and maybe putting a heat shield on the cowling? I put a couple of those behind the turbo in my car and it really helps. Your pipes are certainly closer, but they'll have more airflow around them to help keep the shield from overheating I think.

[cjensen]

Yeah, Will James mentioned ceramic coating and heat shields, but it still means cutting holes and glassing bumps. Ceramic coating is $$$ tho, and I'd still be concerned about rotational clearance on the exhaust and FAB.

[TomNativeNewYorker]

How about ceramic coating the exhaust pipes and maybe putting a heat shield on the cowling? I put a couple of those behind the turbo in my car and it really helps. Your pipes are certainly closer, but they'll have more airflow around them to help keep the shield from overheating I think.

I dont think airflow and cooling would be the only problem.

The picture isnt very clear, but exactly how much space is between the pipe and the cowling?

From the pic, it looks very close if it isnt touching. If you left something like that alone or put some sort of heat shield, you most likely are going to have chaffing and fretting damage.