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Old Apr 05, 2014, 08:09 PM
Registered User
United States, CA, Menifee
Joined Jul 2005
324 Posts
Build Log
1/8th Mig-21MF scratch build

You guys been wanting a scale 90-100mm edf Mig-21MF? Here it is. Being built from Tim Farrell plans. Going to make the plugs for the fuse,wings and stabs. Going to put flite metal on entire Mig. Make every panel line,rivet,bump,bulge and blister on it. Going to do composite foam wings and stabs with epoxy glass skins on wings and stabs with all panel lines and rivets. Going to make this one into one slick kit. In the pic is the Mig jig for the fuse. Want to make fuse perfectly straight. Found a few problems with the plans. F4 former to low on the sides. F6 and F7 are mismarked on the plans. F-8 is to low on the top. Going to fix all these problems before sheeting the fuse. Other problem was trying to find a set of electric retracts to fit the thin wing. Found a perfect all aluminum set of electric retracts to handle the weight and fit wing. Hobby King sells all 3 retracts for $65.00. They also have the struts and 70mm tires and wheels. In the pic on my build table you see a Efflux Jetfan Eco 90mm fan thats going in the Mig. Motor is a Het 700-68-1500 and a Castle Edge 100amp
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Old Apr 05, 2014, 10:47 PM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
Joined Apr 2006
20,965 Posts
First rate looking build Tim. Ill be watching your progress.im sure many will watch learn and help you if you need it.we saw a HET might 21 fly today at the basin .it flew well.
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Old Apr 06, 2014, 12:40 AM
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United States, CA, Menifee
Joined Jul 2005
324 Posts
Mig-21

Thanks for that Rodger. Got to fix a few things on it from the plans. Fuse is going to be for a plug so I can find someone to make a mold as I want to make kits of the Mig-21MF as their are no 90-100mm Mig-21s on the market. Should have the XRP 90mm 14 blade fan, motor and esc next week for the F-100 so we can fly it in a couple of weeks
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Old Apr 06, 2014, 06:07 AM
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Finland
Joined Jul 2004
676 Posts
Looks neat. Always nice to see classic MiG!

A few years ago I have drawn mig-21 bis 90mm version cad 2d drawings with my friend. For 90mm fan the plane is around 2m long.... and scale wheels are about 10cm diameter. I planned making wing thicker at the root to accommodate 45 degree rotating retracts. The retracts would turn like in real one but without wheel rotation vertical. It would be retracted halfway into the fuselage.

Be sure to desing intake correctly, forked for front wheel?
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Old Apr 06, 2014, 08:55 AM
jean-claude Terrettaz
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Carp, Ontario, Canada
Joined Mar 2000
1,469 Posts
I scratch built one from plan , Herb did a better job to , was for a 100 mm fan. I'm still owns mine . Was planning to put a small turbine in.... Was flying Ok , the retract was to far from CG and needed lot of runway for take off, moved forward and is better now. I use TamJet air retract.
But I would like a nice one for a 90 mm fan , WE NEED ONE.
A swiss company made a nice one for a 120 mm with sport wing ,I think they stop the production, I should buy one.....
I will follow this thread for sure
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Old Apr 06, 2014, 10:31 AM
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United States, NV, Reno
Joined Mar 2000
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Woah, I love the -21, this will be fun to watch. Nice project!
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Old Apr 06, 2014, 10:35 AM
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United States, CA, Menifee
Joined Jul 2005
324 Posts
Mig-21

I scratch built a B-58 a couple of years ago and I know the need for proper landing gear installation. Mains have to be slightly behind cg. I built a Century Jet F-105 Thud awhile back. Thud has a pretty heavy wing sweep. So Century Jets solution was to bend music wire to sweep angle then they angled the retract mount in the opposite angle. That way when the gear retracts into the wing it sits flush. When gear comes the wheel will be on center line. Pretty smart on their part. Going to be same way with Mig-21. Go look at Century Jets website and look a the pic of the F-105 landing gear and you will see what I am saying. Reason Mig had the landing angled and retracts toward the front of plane is because the wing is so short if you angle the gear you gain length in the strut as the Mig needs it to sit a little high. Going to fix the problems with the plans and make this one scale Mig-21 as it is my favorite. Mig-21 is 64" long with a 36" wingspan. Going to put all the panel lines,bulges,blisters and rivet details on the Mig so when the mold gets made it will be awesome.
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Old Apr 06, 2014, 10:39 AM
tom
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USA, LA, Natchitoches
Joined Apr 2004
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Quote:
Originally Posted by bidule View Post
I scratch built one from plan , Herb did a better job to , was for a 100 mm fan. I'm still owns mine . Was planning to put a small turbine in.... Was flying Ok , the retract was to far from CG and needed lot of runway for take off, moved forward and is better now. I use TamJet air retract.
But I would like a nice one for a 90 mm fan , WE NEED ONE.
A swiss company made a nice one for a 120 mm with sport wing ,I think they stop the production, I should buy one.....
I will follow this thread for sure
I've been keeping my fingers crossed for a 90mm mig 21 for years. all anyone is doing are remakes of the same old thing. your mig is beautiful to say the least, good job.
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Old Apr 06, 2014, 12:39 PM
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Irvine, Calif USA
Joined Feb 1999
12,176 Posts
Quote:
Originally Posted by bidule View Post
... I still own mine . Was planning to put a small turbine in it ...
Hey JC, Mine's still in one piece as well Yes that plan had a few issues ... I ended up partially re-drawing a few formers :

http://www.rcgroups.com/forums/showt...1216363&pp=100

.
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Last edited by Herb; Apr 06, 2014 at 01:19 PM.
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Old Apr 06, 2014, 01:11 PM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
Joined Apr 2006
20,965 Posts
See Tim look at all the help and interest you are gaining.the Mig-21 is a great choice.
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Old Apr 06, 2014, 02:05 PM
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Finland
Joined Jul 2004
676 Posts
If I happen to have the mig cad drawing somewhere I can post it to you, if needed. It has ducting outlined for 90mm fan.
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Old Apr 06, 2014, 03:23 PM
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United States, CA, Menifee
Joined Jul 2005
324 Posts
Mig-21

Been wanting to build the Mig-21 for a long time Rodger. Hassle on this one is trying to get fuse dorsal right and that slight coke bottle shape on the Mig
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Old Apr 06, 2014, 03:24 PM
jean-claude Terrettaz
bidule's Avatar
Carp, Ontario, Canada
Joined Mar 2000
1,469 Posts
Herb you are the Master of EDF , your Mig is gorgeous and flew very well.
I hope Tokenkopf will sell baby's from is mould!!
I'm reserving one.
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Old Apr 06, 2014, 09:12 PM
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United States, CA, Menifee
Joined Jul 2005
324 Posts
Mig-21

That's the whole premise behind me building the Mig-21MF. Their are no 90-100mm Mig-21s on the market. Going to make some very nice easy builders kits because lets face it I see too many of the same jets being kitted. Will have all the formers and longerons glued in and on the jig tomorrow ready for balsa sheeting
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Old Apr 07, 2014, 04:20 PM
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United States, CA, Menifee
Joined Jul 2005
324 Posts
Mig-21

Here is a pic of the fuse skeleton done and ready for 1/8 balsa sheeting. What a Pain to get that fuse totally straight
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