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All things cowling

DanH said:
Did you complete that step?
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Before you drew the line, you used the phrase for putting a cleco in the inlet, "when trimmed." That indicates that you referenced something when you trimmed, ummm, something. Then draw the line. Then fit the thing over the engine and make the tabs over the cylinders.

As I understand this, you're trimming something before you ever fit it over the engine. But I'm reluctant to trim anything around the edges of the inlets -- if that's what you're suggesting -- because I would think how the two cowl pieces relate all the way from front to back, is going to have some impact on the accuracy of the trim one makes somewhere in the front.
 
Brian, can you tell us a bit about what you used, what the overall paint scheme looks like? As Dan said, awesome!

hydroguy2 said:
Here's a motivational pic for you.
RV-7build977.jpg
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Bob Collins said:
As I understand this, you're trimming something before you ever fit it over the engine.
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Correct, across the nose, while it is on the floor, just like in the photo.

But I'm reluctant to trim anything around the edges of the inlets -- if that's what you're suggesting -- because I would think how the two cowl pieces relate all the way from front to back, is going to have some impact on the accuracy of the trim one makes somewhere in the front.
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Re-read....Allen and I both told you you'll need a stick cut to firewall height.
 
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I saw Alan's ("2 by cut") but don't see yours. The reason why a reference to the "height" at the firewall" concerns me (without actually fitting to the fuselage first) is because it's a curving height that changes quickly from point to point. And, yes, I could cut a stick to a given height (after using a plumb bob to make sure it's exactly straight) at a given point, but then I'd have to find EXACTLY that same point on the cowling halves to place the stick.

I suppose the centerline on the nose is the obvious starting point. But without fitting the bottom half, it's difficult to determine EXACTLY where the centerline on the bottom piece is... and, of course, as you pointed out there's the danger of a twist messing up a cut too.

I'm not challenging your method, nor am I ignoring what you wrote. I'm just asking questions. Thanks for your obvious patience!
 
James Cowl Help

Has anyone used James cowl on IO360 A1A (200 HP) with servo mounted at forward position instead of bottom of engine? Need help with air induction
design. Also, would you need alternate air induction tube?
 
richphil said:
Has anyone used James cowl on IO360 A1A (200 HP) with servo mounted at forward position instead of bottom of engine? Need help with air induction
design. Also, would you need alternate air induction tube?
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rich-sent you a PM
 
Area behind cowl will likely need some new glass

Bob,

I figured the 2x4 (or 1x2 in my case) cut to length of firewall was not all that critical, rather just a means to keep cowl halves roughly lined up. I measured it with a tape measure and just eyeballed it so it was approximately midway between the sides when I stood the whole thing up on the floor.

Knowing what I know now, I would have been better off to have just gone ahead and "wacked off" the jongle and anything else that got in the way of making the 13" spinner back plate line up with and center on the cooling openings (like in Dan's 08/24/10 post). The curved fronts of the cowl halves would just not slip inside each other so I should have cut them off similar to Lar's 8/26 photos and Dan's 09/05 sketch. As it turned out for me I just got there after multiple on again/off again fittings of the lower cowl. Even after proceeding slowly I still ended up with gaps in the parting line behind the cowl that will have to be "doctored".
 
AFulmer said:
As it turned out for me I just got there after multiple on again/off again fittings of the lower cowl. Even after proceeding slowly I still ended up with gaps in the parting line behind the cowl that will have to be "doctored".
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Yeah, I just got there today. I whacked off the front corner and things fit better.

BTW, I could not get a 13" circle in the spinner cutout. The width was 13 1/4" so I kept the vertical measurement at 13 1/4" too (basically this leads to 1/8" showing around the edges of the spinner backplate).

I've also lowered the top cowl about 3/16" below the top of the spinner plate, so -- of course -- when I look at the thing from the front, there's more of the lower part of the spinner circle on the bottom cowl showing than on the top. Can't say I like seeing that and not knowing how much the engine is going to sag.

My goal for tomorrow is to figure out how to get the bottom cowl on for fitting without having to take the spinner backplate off. I suspect it means slicing a little more of the nosegear leg hole in the bottom of the cowl.

It's starting to make sense to me and eventually I'll get it to the point where it's passable. Though parking in the RV corral now at Oshkosh someday is definitely out of the question.
 
Some time back there was a picture in the RVator about how to trim the bottom cowl around the spinner opening to make it easier to remove.

Could someone point me to that picture?

Thanks!
 
Don't forget there will need to be paint gaps at the firewall and the top and bottom split for primer and final painting. A tight fit will result in many fowl words being expressed verbally after you have final paint and the chips start popping off. We use a credit card gap minimum.
 
Drilling top-to-bottom cowl hinges question

I'm ready to attach the hinges along the horizontal sides of the cowls. (using 1/4 turns around firewall)

As I understand, the procedure is to drill-in the hinge to the lower cowl first with the hinge center drifting up slightly at the aft end.
In drilling the top cowl to the hinge, is there another 'trick' other than using a back-light to shine through the holes of the hinge? :confused:
(I also know to use epoxy on the hinges for extra strength.)

Any advice on this or "gotchas" much appreciated.
 
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Proud of this Invention

Just had to figure out how to find the holes in the hinges and this set up worked great. These LED's were from the auto store and when lined up on the hole projected a round light that was very easy to centerpunch and drill. Its a little single LED in a popsicle stick held on the hole and lighting up the outline:

img0223h.th.jpg
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I was amazed at how well the centerpunch and hole lined up.
 
Found it.

N941WR said:
Some time back there was a picture in the RVator about how to trim the bottom cowl around the spinner opening to make it easier to remove.

Could someone point me to that picture?

Bill R., The 2007-4th issue of the RVator page 15. Sorry , I dont have a scanner or I'd post it for you..
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Thank you, Dan

This image is worth a thousand words, I've been thoroughly confused reading the RV-8 cowling install instructions and looking at DWG48.

Vans could use a tech writer with your talent to assist the great unwashed masses in this matter. :)


DanH said:
Correct, across the nose, while it is on the floor, just like in the photo.



Re-read....Allen and I both told you you'll need a stick cut to firewall height.

Click to expand...
 
Read all these articles and seen the overlap you guys seem to have on the sides. I believe Vans sent me a used cowling as there was green body filler on the front and when the cowling were put,the fuselage I had gaps along the sides and the cowling openings were not even. We made it work with a lot of fiberglass I work.
After establishing the 2 inch line drawn around the fuselage and making the first cuts whereby letting the top,cowling rest on the skybolt plated the two haves finally met.
:(
I should have sent the cowling back to vans.
 
Pulling this really useful thread back out of the mists of time...

DanH, on this post, when you mentioned trimming: "trim either or both to an imaginary line which exactly bisects a 13" circle. The small white tabs set equal inlet size, ie a level split line. When trimmed install a single cleco as far back inside the inlet as possible. Doesn't matter if it is in a screw location; you can fill any extra hole later. "

Did you mean trimming the inlet and spinner opening flanges so that they butt up against each other and no longer overlap? If so, what's to prevent a gap from opening with various air pressures? Also, how would a cleco in the inlet hold anything together if the flanges weren't overlapping?

Thanks!
Russ
 
Oh, also, I'm unfamiliar with the term "Boot Cowl". My cowling only came as 2 large halves and I searched the Vans PDF manual and found no instances of "Boot".

Thanks,
Russ
 
grayforge said:
Pulling this really useful thread back out of the mists of time...

DanH, on this post, when you mentioned trimming: "trim either or both to an imaginary line which exactly bisects a 13" circle. The small white tabs set equal inlet size, ie a level split line. When trimmed install a single cleco as far back inside the inlet as possible. Doesn't matter if it is in a screw location; you can fill any extra hole later. "

Did you mean trimming the inlet and spinner opening flanges so that they butt up against each other and no longer overlap? If so, what's to prevent a gap from opening with various air pressures? Also, how would a cleco in the inlet hold anything together if the flanges weren't overlapping?

Thanks!
Russ
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Yes. I drilled the plywood circle and clecloed to the upper and lower halves. I had a hole in the center of my disk that fit tightly to the extension hub, then drilled holes for the prop bolts. The disk could slide fore/aft on the prop attachment bolts.

You could use aluminum tabs too, but put two holes in one side so they don't wobble.
 
Ah, thanks Dan, that explains it perfectly. I'd thought you meant "Cut off the joggles and leave it at that." vs "Cut off the joggles and build your own."

I did something similar (ripping apart and rebuilding) with the vertical stab fairing... it didn't fit very nicely, so I cut it in half along the longitudinal axis, fit each half in place, then glassed the pieces back together. Fiberglass can be pretty cool.

Thanks again!
Russ
 
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