HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Dec 25, 2007, 07:55 PM
Registered User
Ann Arbor, Michigan, United States
Joined Sep 2003
4,737 Posts
Build Log
MiG-15 "Fagot" ParkJet Build Thread

alrightee, we've got the next in the MiG series coming up here. this is a pusher MiG-15 at 1/11th scale to match my MiG-21 1/11th scale design. they use very similar techniques. so, if you've built the MiG-21, this will be a breeze because the parts count is much smaller (ie, no turtledeck ). the only thing a little different is the high stabilizer and angled elevator planes. so, i utilized the same design as my Boeing 727.
we're lucky here because i've enlisted the help of a courageous beta builder! jasta has agreed to be a guinea pig to test out the plans and help figure out the proper control throws and CG. he's a super fast builder, so it'll greatly improve the time to which i can get the plans released. in addition, we're lucky enough to be honored by J's magical touch. he is building an enlarged modified version to match his 1/8th scale F-86. that should be a real treat. i gave him enlarged versions of this MiG-15 design, but as you'll see, i think he uses it primarily as a reference as opposed to a set of typical plans. he'll be introducing some new building techniques, so hang to your horses... should be a great ride!
here are some stats:

MiG-15 "Fagot" Parkjet
1/11th scale
WS 36"
L 39-1/4"
WA 260sqin
wt ???
2 or 3 servos (1 for elevator, 1 or 2 for ailerons)

i designed 2 versions, the traditional fighter as well as the 'transport' version with the extended canopy. the only difference is the canopy, so you can get 2 birds for the build of 1!... that's my kind of math

plans will get posted after a successful maiden... this is where jasta's help will greatly improve release time.
-beanie

Update (1-22-08): plans released! current version is 1.2. see below
Update (2-28-10): untiled version 1.3 available. see below
beanie is offline Find More Posts by beanie
Last edited by beanie; Feb 28, 2010 at 01:06 PM.
Reply With Quote
Sign up now
to remove ads between posts
Old Dec 25, 2007, 07:59 PM
That thing's operational!
birdlives1955's Avatar
New Orleans/Dallas
Joined Jan 2006
4,706 Posts
All right, nice! Time to grab the popcorn.
birdlives1955 is offline Find More Posts by birdlives1955
Reply With Quote
Old Dec 25, 2007, 08:11 PM
Registered User
Ann Arbor, Michigan, United States
Joined Sep 2003
4,737 Posts
man, close one! i thought i had 'lost' or deleted all my early build pics. bummer! luckily, i found it hiding out in a folder that it was never supposed to be in. not that its any rocket science. the build order follows all of my more recent designs.
first pic is just to give an idea of the parts count. not too bad. easily cut-outable (if that's even a word) in a single evening.
i started off with the wing this time. i cut the ailerons free. then i installed the CF. i believe i used 5mm dia this time. i used hot glue for essentially the entire build.
-beanie
beanie is offline Find More Posts by beanie
Reply With Quote
Old Dec 25, 2007, 08:31 PM
Registered User
olympic class's Avatar
Joined Jun 2006
246 Posts
YES! Looks great, I can't wait to build it.

-Ed
olympic class is offline Find More Posts by olympic class
Reply With Quote
Old Dec 25, 2007, 09:42 PM
Now in TN!
J Morgan's Avatar
Chapel Hill, TN USA
Joined Apr 2001
24,381 Posts
OK, I'm pretty far along on my version but I get tired of typing so I'll add some now and some more in the morning. Pace myself you know.
I have wanted to do a "lost foam" method fuselage for a long time. Never got started on one and I felt this build would be a great one to try it on. After many e-mails to Wade Joos and Jerry Hall, I finally got the courage to start it.
Like Ben said, mine is ~1/8th scale. My printer cheated a little and printed out at about 94% so we're still close. Close enough for me at least. I printed the plans out and used them for the fuse outline. Then taking some really big foam blocks, rough cut the fuse on my hot wire cutter.
It was just a matter of craving & sanding after that. Sounds quick, doesn't it?
Well, carving by hand and trying to get a symmetrical fuse wasn't easy. I made negative templates to keep everything under control. Finally I felt I had a worth y smooth enough fuse.
In the "lost foam method", the foam fuse is covered by FG/epoxy and then the foam is melted out with gasoline or lacquer thinner. Sounds good but if you have ever melted foam, you know what kind of mess there is. I read as much as I could find and in one article, a guy used packing tape to seal the foam fuse and then the foam after dissolved left a cleaner fuse because you can pull the tape out bringing alot of the mess with it.
I discussed this with Wade and he came up with the idea of :
1. Wrap the foam mold in packing tape
2. Give it two coats of wax
3. Give it one coat of PVA
4. Lay up the glass and let cure.
5. When cured, sand while still on the mold
6. Cut a seam down the length and peel the FG fuse off the mold
7. Glue and reinforce the seam.
You're left with a FG fuse AND still have the mold intact.
Problem is, we weren't positive that it would work. Well, Wade was, I wasn't.
So that's what i did. Aftr sanding the foam fuse down, i spackled the whole thing, let dry, and then sanded down smooth again. Then packing tape was laid on lengthwise. I hate packing tape & fim coverings. I suck at them and I hate using them. Packing tape is nothing but film covering in a sheep's clothing. I fought thru it, had several places where there were wrinkles. I just chalked them up to bad technique and went on. I figured I could sand out the imperfections in the glass. Now that's stupid and I know it but I was losing my patience at the end of the day.
So I went ahead and gave the plug two coats of wax, one coat of PVA and let dry.
J Morgan is offline Find More Posts by J Morgan
RCG Plus Member
Latest blog entry: OV-10A Bronco from Palmer Plans
Reply With Quote
Old Dec 25, 2007, 10:09 PM
Now in TN!
J Morgan's Avatar
Chapel Hill, TN USA
Joined Apr 2001
24,381 Posts
The last pic shows the plug with one layer of 5 oz glass and then another over that of 2 oz glass. The lighter weight is used on top so you have a smaller weave to fill.
I let it cure overnight but forgot one thing. My heat was set at 65 degrees in the shop. I like cool temps to work in, epoxy likes temps over 70 degrees to cure correctly.
The next morning, using a dremel cut off wheel, I cut a seam along the bottom the length of the fuse. Wade suggested thin Mylar strips to force between the FG and the mold to help it release. I couldn't find my Mylar supply so I used thin plastic and made the tools in the pics. By sliding one of them in under the glass I worked the FG off the mold. Problem number 1.
Going lengthwise with the packing tape left seams that the tool would hit and didn't want to go further. Like hitting a stop. Problem number 2. The wrinkles.
The tool would hit the wrinkles and again, just like a stop, wouldn't want to go any further. But I worked and worked and worked. It took over an hour and the glass was released. I turned the fuse over in the spit and the glass just spread and fell off! It worked wonderfully! Problem 3. The epoxy hadn't cured correctly because of the temp. To make a long story shorter, it would work with another coat of glass I think. But I didn't want to chance it, it was just too soft. So I set it aside and did another. But this time, I removed all the packing tape and retaped it. I went around the girth with the tape instead of lengthwise. This way the tool would slide along the seams instead of hitting them. I also took my time, an hour or more, and made sure I had almost no wrinkles.
The second fuse was done as the first. The next day, I mixed up some microballoons and epoxy and gave it another coat. When dry, I wet sanded the whole thing while it was still on the mold. Then I cut the seam, started working on separating the glass with the plastic tools and BOOM! It was off in less than 10 minutes. Much stronger feeling too. I now had a workable fuse.
It weighed in at 12 oz. Not too bad for a 41" long fuse with a girth of ~8"
J
J Morgan is offline Find More Posts by J Morgan
RCG Plus Member
Latest blog entry: OV-10A Bronco from Palmer Plans
Reply With Quote
Old Dec 25, 2007, 10:20 PM
Now in TN!
J Morgan's Avatar
Chapel Hill, TN USA
Joined Apr 2001
24,381 Posts
I used CA glue to tack the seam together and then glassed a strip of 2 oz glass over the seam to reinforce the joint. I also used 5 oz cloth to glass an add'l layer inside both ends to rinforce them. here I screwed up again. I had forgotten to wash the PVA( green release stuff) out of the fuse. Hopefully the glass won't separate there.
Finally I remembered( or Wade reminded me!) to wash it out so I took it to the bathtub and scrubbed it out with sandpaper and warm water. It then took on the right color.
I cut out 1/4" balsa nose ring and lite ply bulkheads for it. These will be installed when the wing is cut in.

J
J Morgan is offline Find More Posts by J Morgan
RCG Plus Member
Latest blog entry: OV-10A Bronco from Palmer Plans
Reply With Quote
Old Dec 25, 2007, 10:25 PM
Registered User
Turn n Burn's Avatar
Joined Aug 2007
951 Posts
Great stuff Mr Morgan, thanks for sharing some techniques with us....Tim
Turn n Burn is offline Find More Posts by Turn n Burn
Reply With Quote
Old Dec 25, 2007, 10:29 PM
That thing's operational!
birdlives1955's Avatar
New Orleans/Dallas
Joined Jan 2006
4,706 Posts
Wow! That's just the ticket J, super work! Man, what a really cool idea that you guys came up with, that's so neat. Can't wait to see what that'll look like with some paint on it.
Wow, that is so cool about being able to keep the mold, just think if you ever needed to make an extra fuse it looks like a lot of the work would already be done. Really nice idea.
birdlives1955 is offline Find More Posts by birdlives1955
Reply With Quote
Old Dec 25, 2007, 10:31 PM
Now in TN!
J Morgan's Avatar
Chapel Hill, TN USA
Joined Apr 2001
24,381 Posts
Thanks Tim,
Stay tuned, we're just getting warmed up! This is uncharted territory for me and sone of the ways I do things I'm sure won't be the easiest or best. But they will just be the way I think them out.
Wade seemed pretty excited because this way the mold is undamaged and ready for another go. And he knows fiberglass! Me, I wasn't smart enough about this stuff to get excited.
Yeah Matt, I glassed up both fuses in about 2 hours each. It doesn't take that long once you have everything all lined out.

J
J Morgan is offline Find More Posts by J Morgan
RCG Plus Member
Latest blog entry: OV-10A Bronco from Palmer Plans
Reply With Quote
Old Dec 25, 2007, 10:39 PM
Registered User
Turn n Burn's Avatar
Joined Aug 2007
951 Posts
Im watching this like 10yr old sitting at the camp fire listening to the best ghost story ever told.
Turn n Burn is offline Find More Posts by Turn n Burn
Reply With Quote
Old Dec 26, 2007, 03:42 AM
Registered User
Detlef's Avatar
Germany, Ladbergen
Joined Dec 2006
255 Posts
J, thats an absolutely great idea with your "tab-lock-mechanism".

Why are the best ideas in world so simple? And why donīt I get them?

Detlef
Detlef is offline Find More Posts by Detlef
Reply With Quote
Old Dec 26, 2007, 05:34 AM
Registered User
Ann Arbor, Michigan, United States
Joined Sep 2003
4,737 Posts
man J, that just looks soooo sweeeet! can't see any wrinkles at all from where i'm sitting. also gotta agree with detlef... fantastic idea with the tabs!
how are you fashioning attachments for the fin and wing? do they go only into the fuse or through the fuse to the other side?
-beanie
beanie is offline Find More Posts by beanie
Reply With Quote
Old Dec 26, 2007, 06:58 AM
Now in TN!
J Morgan's Avatar
Chapel Hill, TN USA
Joined Apr 2001
24,381 Posts
The rotisserie type unit is invaluable, I knew I would never be able to do this without something like it.
Fin, Wade asked where the fin was when I sent him pics of the completed fuse. He's right of course, I should have made the fin on the fuse and it would be one nice streamlined unit. Next time.
So the fuse was finished, it amazed me at how fast the second one went. Lay up today, take it off tomorrow. I forgot these pics, they just show the same process.
And then on to the fin & stab.

J
J Morgan is offline Find More Posts by J Morgan
RCG Plus Member
Latest blog entry: OV-10A Bronco from Palmer Plans
Reply With Quote
Old Dec 26, 2007, 07:15 AM
Now in TN!
J Morgan's Avatar
Chapel Hill, TN USA
Joined Apr 2001
24,381 Posts
First I cut the wing shape out so I could determine where it would fit on the fuse. Made a foam stand for it and jigged the fuse up level. Found the location of the LE and scribed a line down the fuse where the wing middle line will run. Both sides. I made this line so that the wing has a 1 degree positive incidence. I'll save these lines so I know where to cut the wing shape out of. After alot of thought, I've decided to make the wing removable and that will means the lower center section will be cut out.
Then it was on to the tail feathers.
They would be two thicknesses of 6mm Depron. Control will be by the system GGRN taught me in his A-4 build. Excellent, strong, foolproof for flying tails. The stabs were routed with a Dremel to accept the carbon tubes, making a sandwich around them. I used a small Dubro wire and plastic sleeve for the pushrod. This will be buried in the fin. Last pic shows a test fit.
OOps forgot, the fin needed strong attachment points so I used the carbon tubes, They will extend down thru the bottom of the fuse and be cut off flush. I'll also use lite ply rings around them to reinforce the glass where they exit the fuse. Also, a lite ply "surround" plate will reinforce the cutout where the fuse slides in the top.

J
J Morgan is offline Find More Posts by J Morgan
RCG Plus Member
Last edited by J Morgan; Dec 26, 2007 at 07:30 AM.
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Alfa MIG 15 Build sarge Parkflyers 170 Nov 28, 2013 05:13 PM
Discussion little scremers jet scream powerd alfa Mig 15 build thread corsair nut Foamy EDFs 265 Mar 06, 2010 07:01 AM
Question Mig 15 home build parabelum Electric Ducted Fan Jet Talk 8 Sep 08, 2004 10:18 AM
Question Mig 15 Build Mopar92 Electric Ducted Fan Jet Talk 4 Aug 19, 2004 12:10 PM
Fantastic Mig-15 and F-86 thread over in Jets FanTasticModels Parkflyers 6 Aug 08, 2002 07:39 AM