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Pepto Pink Cowl

wirejock

Well Known Member
Vans Pepto Pink Cowl 1: Wirejock 0
Some days you get the bear. Some days you get mauled to death by the Vans Pepto Pink Cowl
Clearly I messed up. I barely trimmed anything just to get the two seams straight.
Yes, I know the cowl is over the skin but even after trimming flush, that gap ain't closing.
My plan is to layup a scarf joint on each half seam, but not full thickness. That way the two halves can overlap. Then I cut and fit the cowl to the firewall properly and use a laser level to shoot the side seam cut line. Yes, the bird is level both long and lat. Then finish adding glass to the strip to full thickness.

Anyone have a better solution please let me know. Chime in.
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Yep - you have to creep up when trimming.

After you add glass on the sides, I recommend stopping and installing the prop with spinner back plate before proceeding (as in doing any further trimming). It is hard enough to get the cowl to spinner gap and cowl height right with the real spinner in place, mounted on the prop hub. I would not attempt doing this with a template.

I do use an old Hartzell prop hub for this instead of the actual prop. I do however make sure old hub is a dimensionally exact match to new Hartzell BA prop.

Carl
 
Larry- I know it looks like a massive gap, but referencing that silver cleco for scale, I'm guessing it's probably around an inch, right? I can't help thinking that once the cowl halves aren't being all spread out by the fwd skins it will come together a significant amount, if not all the way.

Remember, it's not just the skin thickness they're riding on right now, its the raduisses (radii?) The big curves on the top skin will eat up a lot of distance.

Is it possible to grab a helper or two and slide the cowl halves fwd until they're butting up against the firewall flange to get an idea of how much they will actually come together? I'm betting it will be more than you think. Either way, you'll have more of an idea of what you're looking at to fix it.
 
Ideas

Thanks. Keep the tips coming.
It's totally my fault. I should have put them on before trimming.
Ralph, thanks so much. Give me a few days to recover from my Pepto Pink binge and I will call.
Carl, thanks. I wish I had the prop. Saving for it. Whirlwind. They really like that thing! Pricey. I'm using a jig and their drawings. Fingers crissed but no doubtt I will get mauled by that bear too!
 
Fitting the Cowling

Yep, lots of opportunity to mess up when fitting the cowling halves. Fitting the prop spinner and backing plates to get the correct spacing and height for the top cowling is really important. I found the Vans instruction sequence to be very helpful to figure out which parts to trim and fit in the correct order to get it all to match and have it looking nice around the inlets. Before scarfing and adding glass I would get one half (probably the top) to fit at the firewall and get the gap between the backing plate and the top cowling correct and the height of the top cowling at the spinner blocked up and correct and then trim the bottom cowling to the firewall to line up fore and aft at the front around the air inlets and make the air inlets match and fit. Then the sides are trimmed to match and provide a straight clean join. Looking at the way yours fits you might find that there is enough meat left that you have dont have to add glass to get a good fit. I think it took me about 3 weeks of solid work to get it right and not overshoot. Most of the time seemed to be spent putting the cowlings on and taking them off.

KT
 
I am with the other guys - - 1. make dang sure the fore/aft is correct for your prop/spinner/cowl clearance. 2. cut and creep up on the aft cut to fit the firewall - a big task to get it all flat and gaps even. 3. secure the cowl around the firewall then see how the split line turns out.

Lots of things to do before you come to a conclusion on the split line. Oh - - I was fitting my james and only 1/8" was removed for the split, but the split was not parallel to the longeron. It was at an angle and hit the firewall 1" high. Silly assumption. I had to de-rivet and re-make all the sky bolt mounts down both sides to get the locations right - - I also was spacing the SB's and discovered the sides of the cowl are not the same length due to engine thrust angle. Like a Michael Angelo statue. :D

Stuff happens and none of it is the end of the world. Its just work and sometimes it's a lot, but wade through. Nice words, but I got really excited about a few things too:eek::D I spent more time wringing my hands over an issue(s) than diving in and fixing it.

I got a good tip from Will James for making the cowl spinner gap even, When all finished, take a piece of glass and slide it in the gap, install three screws in the cowl face to touch the glass. Then butter up the cowl face and press the glass to touch the screws. It makes the gap plane nice and even.
 
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Gap

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I got a good tip from Will James for making the cowl spinner gap even, When all finished, take a piece of glass and slide it int eh gap, install three screws in the cowl face to touch the glass. Then butter up the cowl face and press the glass to touch the screws. It makes the gap plane nice and even.

That's a pretty cool tip.
 
Make sure the slot for your nose wheel is long enough and not keeping the bottom cowl from coming up to meet the bottom of the fuselage.
 
Larry,

The A models need a longer slot than you think. The bottom cowl needs to drop down to clear the prop and front baffle ramps before you can move the bottom cowl forward.
Don't fix that slot until after you have your baffles done. It could be covered by your nose gear-to-bottom cowl fairing, which you can buy or make.
 
Bottom cowl

Larry,

The A models need a longer slot than you think. The bottom cowl needs to drop down to clear the prop and front baffle ramps before you can move the bottom cowl forward.
Don't fix that slot until after you have your baffles done. It could be covered by your nose gear-to-bottom cowl fairing, which you can buy or make.

Thanks. I see some stuff on the drawing. Looks like some sort of removable panel to help clear the nose gear.
 
Larry you will get this fixed man. Also a +1 for what Carl said. Without the prop on or something insanely accurate like an actual hub you are playing with fire. Too large of a gap is ugly among other things and too small will seriously make it a pain in the a$$ to get the bottom cowl off! Mine is 3/16" approximately and even then the bottom cowl is a pain sometimes.
 
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Thanks. I see some stuff on the drawing. Looks like some sort of removable panel to help clear the nose gear.

Not sure if you are going with a 3 or 2 blade prop but if you go with a 2 blade you will find that only the rear plate/bracket has to be removed to get the cowl off. At least that is my experience.
 
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Prop hub

Larry you will get this fixed man. Also a +1 for what Carl said. Without the prop on or something insanely accurate like an actual hub you are playing with fire. Too large of a gap is ugly among other things and too small will seriously make it a pain in the a$$ to get the bottom cowl off! Mine is 3/16" approximately and even then the bottom cowl is a pain sometimes.

Sorry. No choice. Money isn't there yet for my Whirlwind 300RV.
I have to try or add time to the end when I really want to be flyjng.
I do have an incredibly accurate cowl jig with a hub duplicate and using Whirlwind CAD drawing. I'm shooting for a bit more space because it's a three blade. If I mess up, it won't be the first, or last time.
Fingers Crossed.
 
Sorry. No choice. Money isn't there yet for my Whirlwind 300RV.
I have to try or add time to the end when I really want to be flyjng.
I do have an incredibly accurate cowl jig with a hub duplicate and using Whirlwind CAD drawing. I'm shooting for a bit more space because it's a three blade. If I mess up, it won't be the first, or last time.
Fingers Crossed.

You are a pretty meticulous guy Larry so I have faith in you. Just make sure to triple check haha. Feel free to send me an email if you have questions. Or give me a call, I think you still have my number. I know the feeling quite well at that stage of the build. I just wanted to start flying! lol

P.S. Once the cowl and baffles are done it's all pretty easy from there. :)
 
Larry,

That gap will close a lot more than you think once it's trimmed to the firewall. The cowl is not only sitting on the top and bottom of the firewall but also being spread out on the sides. I wouldn't add the scarf joint until you know what you need. At that point you may find it better to only add to either the top or the bottom (if you need to add at all). I would follow the plans and build on! Trim the top cowl, then the bottom, and then decide what needs to be done with the sides. You are good at fiberglass, so you will getting looking good.

A word of caution about the top cowl: As the cowling settles down into place, the sides will get much shorter. Start at the top center and trim a little at a time as you work toward the sides. If you cut to the trim line all at once, you may find that the sides are coming up short of the firewall once it fully sits down into place.

.....and get that prop ordered! Your bird needs to fly!!
 
Hi Larry, I cut my top too close to the prop and if I trim the back my gap on the lower back will be more so probably have to do some fiber glassing. Have both off if you want to take them up and see what they look on yours let me know.
My lower cowl has the nose on for the carb but should fit on yours, they have the hinge's on.
 
I am with the other guys - - 1. make dang sure the fore/aft is correct for your prop/spinner/cowl clearance.

This is easier said than done, too! When I was trimming my cowl, I thought it would be foolproof to cut a 1/4" piece of plywood as a spacer and keep it behind the spinner at all times, to ensure an even 1/4" gap. Every trim I did was with the front of the cowl flush with the aft of that 1/4" plywood. Sure enough, when I took the wood spacer away and re-installed the spinner and prop, the gap was 3/16" on one side and 5/16" on the other side :mad:. Not sure if I'm just going to live with it, but I can confirm the cowl trimming is a difficult job.
 
Cowl

Hi Larry, I cut my top too close to the prop and if I trim the back my gap on the lower back will be more so probably have to do some fiber glassing. Have both off if you want to take them up and see what they look on yours let me know.
My lower cowl has the nose on for the carb but should fit on yours, they have the hinge's on.

Thanks but no need. It's fixed. Fiberglass is easily repaired.
I expect a little error when the prop and spinner are mounted. Previous posting about using some Micro and a piece of glass will easily fix that.
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Larry, you need the engine to do the baffles, also to accurately do the cowl you need the engine & prop & than to finish off the baffles. So why not park the cowl for now & concentrate on all the other stuff & leave it for later?
Maybe better than cursing at that 1/4" offset in fitment that becomes apparent when the big pieces arrive.
Yes there is the temptation to see the smooth lines, but...
 
A better mousetrap invented by a friend ... the post aligned with the center of crank allows for perfect alignment.

Once the two halves of the cowl are roughly fitted together, the assembly can be slid back on and the rear edge trimmed until the gap behind your spinner plate is set. Then they can be further fit together along the horizontal seam or installed one at a time for baffle trimming.

Reduced my cowl install time to about 10 hours.

Pretty smart mouse
 

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Fitting the cowl. My method.

I fit my top cowl to the fire wall first. I first put the forward edge of 2” blue tape on the leading edge of the forward skin mounted to the fire wall. . The aft edge of the tape is adhered onto the forward skin.
I then put the top cowl on with the required space aft of the spinner. It was about 1” long. I then took the 2” tape and aligned the aft edges of the two bands of tape. I then traced the forward edge if the tape onto the cowl with a black sharpie. Cut the cowl and trimmed to fit to the fire wall/ forward skin.

Once the top cowl was fit, i installed the lower cowl in the same manor. Trimming to the fire wall. With the top and lower cowl fit, i then marked and trimmed the
overlap on the sides.

Hope this helps.
 
Larry, you need the engine to do the baffles, also to accurately do the cowl you need the engine & prop & than to finish off the baffles. So why not park the cowl for now & concentrate on all the other stuff & leave it for later?
Maybe better than cursing at that 1/4" offset in fitment that becomes apparent when the big pieces arrive.
Yes there is the temptation to see the smooth lines, but...

Thanks
I have everything but the prop. Engine jnstalled. Need to do baffles but the cowl needs to come first. Prop order goes in when I know it will be installed and flying soon after so the time clock on overhaul doesn't expire before it even gets airborne.

A better mousetrap invented by a friend ... the post aligned with the center of crank allows for perfect alignment.

Once the two halves of the cowl are roughly fitted together, the assembly can be slid back on and the rear edge trimmed until the gap behind your spinner plate is set. Then they can be further fit together along the horizontal seam or installed one at a time for baffle trimming.

Reduced my cowl install time to about 10 hours.

Pretty smart mouse

Yes. I have it. That's what this is all about. I'm writing a magazine article for builders who follow. Stay tuned.

Dang Larry that was fast!

Thanks. Fiberglass I can fix!

I fit my top cowl to the fire wall first. I first put the forward edge of 2” blue tape on the leading edge of the forward skin mounted to the fire wall. . The aft edge of the tape is adhered onto the forward skin.
I then put the top cowl on with the required space aft of the spinner. It was about 1” long. I then took the 2” tape and aligned the aft edges of the two bands of tape. I then traced the forward edge if the tape onto the cowl with a black sharpie. Cut the cowl and trimmed to fit to the fire wall/ forward skin.

Once the top cowl was fit, i installed the lower cowl in the same manor. Trimming to the fire wall. With the top and lower cowl fit, i then marked and trimmed the
overlap on the sides.

Hope this helps.

Yes. Basically the process I'm using. Minor tweaks for the article.
 
Hi Larry,

I've got a spinner and backplate for a 300RV prop sitting in my hangar unused right now. If it'd help with your fitting, I'd be happy to loan it to you. At some point it will be installed, along with a 300RV prop, on my Glasair 1RG, but for now, it sits in my hangar collecting dust.

I have about 3 yearlong projects going on at once, so heaven only knows when I'll be working on the Glasair G3x installation and FWF upgrades again. You could probably have the spinner for months!

Let me know... I'm in Loveland quite a bit and could also meet you at BDU if you visit DP and his RV-3 project.

Rod
 
Spinner

Hi Larry,

I've got a spinner and backplate for a 300RV prop sitting in my hangar unused right now. If it'd help with your fitting, I'd be happy to loan it to you. At some point it will be installed, along with a 300RV prop, on my Glasair 1RG, but for now, it sits in my hangar collecting dust.

I have about 3 yearlong projects going on at once, so heaven only knows when I'll be working on the Glasair G3x installation and FWF upgrades again. You could probably have the spinner for months!

Let me know... I'm in Loveland quite a bit and could also meet you at BDU if you visit DP and his RV-3 project.

Rod

That sounds really tempting. DP is also using 300RV. I dont think it would work without a faux prop for mounting. Might be nice to see it if you could bring it next trip to his house. Always happy to visit.
 
Cowling question on the 7

This should be an easy question if you recall how you positioned the cowl platenuts. I was curious what others have done.

This picture shows RV7A left intake of the bottom half of the cowl. The prints show to install 3 platenuts spaced 1 1/8" and I have a hole spanner in the picture to show that proper spacing. If I evenly put the three platenuts on that flange the most aft would be fairly close to the starter ring gear.

Placing it aft of that starter ring gear leaves me with a small area of fiberglass and moving it forward of the gear pushes the paltenut spacing much closer than designed.

Between the cowl and the gear I would guess that there is a 7/8" space.

Did you space differently avoiding the possible gear and platenut interference?

Not sure if ever the motor would shake enough during start up or shut down to have the gear get close to the platenut.
 

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This should be an easy question if you recall how you positioned the cowl platenuts. I was curious what others have done.

This picture shows RV7A left intake of the bottom half of the cowl. The prints show to install 3 platenuts spaced 1 1/8" and I have a hole spanner in the picture to show that proper spacing. If I evenly put the three platenuts on that flange the most aft would be fairly close to the starter ring gear.

Placing it aft of that starter ring gear leaves me with a small area of fiberglass and moving it forward of the gear pushes the paltenut spacing much closer than designed.

Between the cowl and the gear I would guess that there is a 7/8" space.

Did you space differently avoiding the possible gear and platenut interference?

Not sure if ever the motor would shake enough during start up or shut down to have the gear get close to the platenut.

You will want to hold off on that until you install the baffles and the FAB because you will most likely need to trim the fiberglass inlets a bit. I eliminated the 3rd screw (I'm not the only one). It is working great with just 2 per side. I also didn't want a screw that close to the ring gear.

P.S. It's pretty crazy how much the engine shakes on startup and shutdown.
 
Thanks Jereme

Many Thanks Jereme. Ahhh the baffles and the FAB are those things that could catch me in this area of that aft screw, not only the ring gear. It's always those details I seek so I could avoid the 1 step forward and 2 steps back.
 
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