Fiberglass ducting - RC Groups
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Mar 24, 2012, 09:05 PM
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Fiberglass ducting

Hey folks,

I tried searching for rcgroups for build log examples of people creating ducting out of fiberglass. I know there are build threads out there as I've seen them before I'm just having a hard time finding them again. Anyways, if you know of a good example of someone showing how they've made their glass ducts so I can replicate their methods, I'd be quite grateful.
Last edited by arrowking; Mar 24, 2012 at 10:07 PM.
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Mar 24, 2012, 10:00 PM
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CoolerByTheLake's Avatar
Check out the f-86 build by mshae,just under your post. starting at post 63
I see you new to RCG, so welcome. AIR SALLY is the guru of ducting. Check out some of his posts, or threads. As you are new here, and may not know how to get there, just click on the name in that post, and it will take you to there blog page. Scroll down on right side of page, and it list , posts, and threads started by that person.
Mar 24, 2012, 10:18 PM
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What shapes are you trying to fabricate??

Mar 24, 2012, 10:25 PM
Registered User
I'm doing an intake duct for an F-16. I need to fit a front retract which means some some detailed geometry for the duct. I think the only way I'm going to get the geometry I need is with fiberglass (never done that before).

CoolerByTheLake: Thanks for the tip, looking that up.
Mar 24, 2012, 10:39 PM
up up and away

look here
Mar 24, 2012, 10:42 PM
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CoolerByTheLake's Avatar
This will keep you busy. Here's a link for some threads the have ducting some where in the thread. All you have to do, is open a thread, and in upper right corner, by page count, it says{ search this thread}, just type in ducting. You will have to search some, but it's a start.
Mar 25, 2012, 11:18 AM
Registered User
I just finished building a couple of ducting plugs & may post it in a build thread. My method includes using 3D CAD to layout the ducts (assuming they are 3D ducts, or have bends in their axis in both vertical & horizontal planes). Are you able to use 3D Cad? Nice thing about F-86, its duct only bends in the vertical plane.

Mar 25, 2012, 01:19 PM
Registered User
Yup, I've got a ALibre 3D CAD model of the duct, I just had to make some odd profiles mid span, so I'm concerned about how I'm going to insert it into the bulkheads once made. I'm thinking I either have to make 2 piece bulkheads, or two piece intake duct (which I'd rather not do).

The odd profiles are because I want to put a nose retract and there isn't much room in an F-16 for one, just like its full scale counterpart .

I'm also wondering how I'm going to account for the duct thickness after curing in order to properly size the plug. The duct will have to fit in the bulkheads at the end of the day.
Mar 25, 2012, 01:31 PM
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CoolerByTheLake's Avatar
arrowking, you don't say what size plane, and power you are using.
Mar 25, 2012, 01:56 PM
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It's currently designed around a 64 mm fan. The gears are limiting the size of the airframe to about 1+ m long. Luckily, the frame can technically hold 70mm fan and I think I could even make a 90 mm fan work by shifting a few things around. I think 90 mm will be overkill though. I'm continuing work assuming a 64 mm fan.

I've got a build log going here, however I haven't updated it since I started my ALibre CAD model. I haven't posted any screens of my CAD drawings yet, just a few Blender sketches I used to check rough geometry and grab general dimensions.
Last edited by arrowking; Mar 25, 2012 at 02:04 PM.
Mar 25, 2012, 02:43 PM
it wasn't me flying that plane
Hover or die's Avatar
I am new to ducts s well and just finishing my first set for my raptor..They turned out extremely well..I used the cutout from each bulkhead and glued them to the proper lenth piece of foam and then used hotwire to cut the individual pieces before gluing them together for a solid piece..Then filled with spackle any bad spots..Then glass and epoxy around the plug..2 thick coats for mine..You must wax the mess out of the can then either slit the tube and peel off or melt the foam with acetone..(i did this)..You can see the process in my thread..Pics..Heres a few towards the end..
Mar 25, 2012, 02:50 PM
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CoolerByTheLake's Avatar
Hover or die Your ducts came out great. I like the lower, center one, really shows the the geometry of the intake. Not to mention the amount of work you put in on them. Mark
Mar 25, 2012, 02:58 PM
it wasn't me flying that plane
Hover or die's Avatar
Thank you very much!
I had done lots of glass work on boats but the plug thing is a first and it came out better than I had hoped..Thanks to Rich (LuvEvolution) for the help with the fan lip and AirSally for pointing out my mistakes to make the next ones come out a little easier...Like not using the testors paint..Although after 3 days it hardened up enough to wax and go with it...After the 3rd coat of wax it stopped coming off with the rub off...4th coat came off clean so I knew I had overcome the softness of the paint..
Mar 25, 2012, 03:19 PM
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CoolerByTheLake's Avatar
Maybe it's just me, but it seems there is a lot more scratch building/fabricating parts, or airframes, lately. I have a plug, thats almost ready to glass, and another I'm in the design stage. With both I intend on using the same method you used on your ducts, but for the fuse. Same, just bigger. J Morgan, from airplanes, Electric Foamies (Scratchbuilt), has done a great deal of glassing his foam plugs, with exellent results. Good reading and lots of pointers and tips.
Mar 25, 2012, 05:42 PM
Registered User
Hey Hover or Die,

Nice work on your F-22, I've been watching. Does your intake duct just slide right through every bulkhead? I'm not sure I'll be able to get mine to do that, which is why I was thinking of making a few of the bulkhead sections 2 piece, which isn't really that big of a deal the more I think about it.

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