Engine Cowling Woes

21 posts in this topic

Posted (edited)

 

Well, just when I was close to being finished...I spent a lot of time trying to build baffling on the engine, but the engine was just too close to the cowling.  So, I decided to make a blister on each side of the cowl.  It really hurt to cut up my finished cowl, but it had to be done!

I decided to make some unique shapes and later on I will post the finished product and the shape will make sense.  I made them out of fiberglass, but first made the foam part, then a fiberglass mold, and finally the part!  It took forever and I had to do that for both sides.  I thought I was finished, but the left blister was just a little different from the right so I cut and shaped the foam today and will make the mold and part tomorrow.

I did learn a tough lesson...do not wear those under armor shirts when working with fiberglass!  They trap fibers in the shirt and then they make it into your pores!!!  I look like I have the measles!  Solution = soaking in a Epsom salt bath and cortisone lotion.

Ron

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Edited by RDavidson
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Posted

Ron,   That's what happens when you try to put 180 horses into a 90-horse corral.  :lol:  EDMO

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Posted (edited)

Look on the bright side, I have heard that bumps catch less drag than strait sides, that means you will go faster, Man I wish I knew how to do Fiberglass like that, when I get to my cowl it will be a learning experience for sure.

Edited by TJay

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Posted (edited)

Ron,  Maybe you should have narrowed the cowl and let the jugs hang out in the wind, like the old J3 Cub?  

Makes it a lot easier to change plugs...    EDMO

Edited by EDMO
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Posted

its gotta pro street look ,I like it

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Posted

Look on the bright side, I have heard that bumps catch less drag than strait sides, that means you will go faster, Man I wish I knew how to do Fiberglass like that, when I get to my cowl it will be a learning experience for sure.

Fiberglass isn't difficult, but finishing it is TEDIOUS.  Prime (so you know when you have sanded back to the original surface layer and don't damage the glass), fill, sand, prime, fill, sand, prime fill, sand, fill, sand, fill, sand, fill, sand, fill, sand, fill, sand......................

Repeat until you decide it looks good enough!

Mark

 

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Posted

fill, sand, prime, fill, sand, prime fill, sand,

fill, sand, fill, sand, fill, sand, fill, sand, fill, sand......................

Repeat until you decide it looks good enough!

Mark

 

Then paint it and say @#*&(!#$UYIO or something like that and say.  Sure thought it was smoother than that!  Actually, don't be afraid of fiberglass work.  TJay, you're a pretty handy guy, you won't have much trouble with it.  And remember, if the tips of your fingers feel it when you run them across the piece, it will show up when you paint it.  Play around with some small stuff and work your way up.  Jim Chuk

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Posted

Here's a cheap hydropress technique from Brian Carpenter if you want to make them out of aluminum.  For just a onezy twozy form they can be made of MDF and shaped with a rasp.  

 

http://www.eaavideo.org/video.aspx?v=1277219627001

 

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Posted

That hydro forming is cool!

T jay, I'm figuring out all of the mistakes for you!

 

Ron

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Posted (edited)

Some "free form" hydroforming fwiw...

Edited by Geoffrey Thorpe
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Posted

Some "free form" hydroforming fwiw...

Ha water pipe bomb there, Kind of neat, never thought a pressure washer could do that.

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Posted

Might make a two stroke chamber eh?

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Posted

Well, I now have the left blister fiber glassed in place and ready for filling and sanding.

You will see from all of the pink in my mold that my mold didn't come off the plug very well.  It ends up that you can put too much wax paste on the plug and it causes the plug to kind of wrinkle.  That makes for a lot of sanding and filling!  My favorite...not!

After fiber glassing the part in and filling around it, I found that using a fiberglass filler that has the fiberglass strands in it handles the flexing of the cowl the best.  Then you can use a glazing putty for the small stuff.

It was mentioned before that sanding too deep will get you into troubles of seeing fiber glass lines.  That is correct.  You can fix it with high build primer and might have to use a pinhole filler as well.  I found a new pinhole filling product that I'm going to try, if it works well I will post it here.  As far as high build primer goes, the Superflite primer is really thick, but expensive.  I'm probably going to use a couple of epoxy primer coats.

 

Thanks,

Ron

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Posted

This blister project really slowed me down!  I'm sick of fiberglass, filler, sandpaper and everything else related to it!  I have put it off for long enough though!  I'm getting ready to paint now that the temp has cooled off for a day or two...It looks pretty good minus a small place or two...it should look good at pattern altitude!  That's all I care about :)

 

painty, painty time,

Ron

 

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Posted (edited)

Good work Ron, but I don't think that prop in the photos is going to give you very much climb!  :lol:  EDMO

Edited by EDMO
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Posted

It's experimental Ed!  I think I will leave that on for the DAR inspection and argue that it will work!  :)

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Posted (edited)

Go buy some 2x4 boards at Lowes or Home Depot, and lay them in the sun - once they dry out and warp they might make a  prop - why cant we find kiln-dried lumber now?  Maybe the inspector will think it is factory prop!   EdMO

Edited by EDMO
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Posted

I have to bag on DARs a little bit...the last couple of guys around here that have finished planes pay a DAR to come check them out and get to pay him $400-$500 to tell them that a bolt is too short or that a cotter pin isn't bent correctly!

The last guy needing a DAR is actually on this forum...Jon...he not only got the DAR, but also got two FAA Boobs, they travel in pairs evidently!  Jon said the DAR found two bolts that were too short and a couple of cotter pins bent incorrectly...the Boobs didn't know squat about experimental aircraft and spent most of the time trying to figure out the 51% rule and how it applied to the multiple builders of Jon's plane.  Finally the boobs were convinced that as long as all of the builders were amateurs, not paid to build, that the aircraft was built within the experimental rules and the 51% rule applied to the kit form of the aircraft, not the builders.

So, I find it amazing that the enforcers of the rules don't know the rules, but at least these two boobs were trying to learn...

As for the DAR, it is always good to have another set of eyeballs to look you aircraft over.  Jon said he was very knowledgeable and had a lot of experience.  I just wish it weren't so expensive.  We have an EAA member that does the exact same inspection for free, but he isn't a DAR.

Anyway, if it wouldn't cost me $400, I would love to use Ed's 2x4s for a prop and argue that It is experimental and you can't change my mind, I'm using it :)

sorry for stealing your story Jon...

 

See ya,

Ron

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Posted

---<snip>---



So, I find it amazing that the enforcers of the rules don't know the rules...

See ya,

Ron

Welcome to the world of professional investment management. We call it the GreatMadoffSarbanesOxleyDoddFrankFukup. 20,000+ new regulations with no clear definition of how to comply. :rolleyes:

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Posted

Well, all of the work finally paid off!

A Super Bee wouldn't be complete without some Honeycomb!!! :) 

 

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Posted

Totally Unique!  EDMO

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