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Old Feb 10, 2012, 01:49 PM
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scatsob's Avatar
United States, NC, Jacksonville
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Big CG MIG-27 Foam target drone 120mm conversion

So I was on TAD to Jacksonville FL and did what any self-respecting addict would do and checked to see if anything good on craigslist was for sale. Pickings were slim but one person had some of these old Carl Goldberg foam target drones for $75. I did a little research and found a guy here in NC that converted one to DF with a Dynamax unit. I figured if someone stuffed a Dynamax in one then I could easily fit my 120mm CS fan in it. I emailed the guy and ended picking one up for $40 (he had 15 planes total and would have bought more but didnít have the money).

For the conversion it will be the CS 120mm on 12s. I will use some of the Lander 120 sized metal retracts I just picked up from HK. I plan on glassing the whole plane with 6oz fiberglass. Should be fun. This is sort of a teaser as I wonít start this one for a while, I think. My wife is due with our fourth in three days.

The pictures of the completed plane is the one with the Dynamax fan in it.
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Last edited by scatsob; Feb 10, 2012 at 01:59 PM.
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Old Feb 10, 2012, 09:55 PM
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St.Catharines, Ontario
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a guy here in my town has two of those. both are very sad and need some TLC. I'de love to EDF one of these.

any chance of lightening it up a bit? I've lifted one of them and they seem quite heavy for the side. I'm thinking lots of lightening holes all over the place.
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Old Feb 10, 2012, 11:10 PM
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United States, FL, High Springs
Joined Sep 2005
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bringing back memories

I've had two of these and on 400 watts it was pretty aerobatic as a prop puller, a edf will be neat and can't wait to see it
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Old Feb 10, 2012, 11:21 PM
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United States, NC, Jacksonville
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I’ll make sure to weigh everything before I start dissecting it. It should drop a little weight as most of the fuselage will be gutted for ducting and electronics bays. I have had some correspondence with the person who built the red one and he said it was about 16 lb. and he said it was over-built. So I figure if I can keep it in the 13-15 lb. range it should fly well on 4.4kW and around 15 lb. installed thrust.
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Old Feb 10, 2012, 11:22 PM
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St.Catharines, Ontario
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sounds very interesting. I'm deffinitely watching this one. if it works well, I'm gonna put in an order to buy one of his. LOL.
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Old Feb 11, 2012, 01:25 AM
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Sugar Grove, IL
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I have 4 of them in my basement if anyone is interested.Shipping will be expensive though. Just checked a shipping quote through USPS online for a guy. IL to ND 70 bucks!!!!! Local pickup is better if anyone is interested.
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Last edited by sparkola; Feb 16, 2012 at 03:08 PM. Reason: Update
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Old Feb 11, 2012, 08:49 PM
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United States, NC, Jacksonville
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I managed to make a tiny amount progress tonight after the kids went to sleep. It not much, but I wanted to see how the inlets were going to work. It looks like is going to be pretty straight forward, I just have to be careful to not break the foam while cutting and sanding.

The intake as I have it right now is 115mm by 35mm. That gives 8050mm2 between the two intakes. I measured the fan and got an FSA of approximately 9740mm2. So as it sits the intake is about 80% FSA. I will probably open it up a little to get somewhere in the 90-95% FSA range but I want to leave enough room on the fuselage side to add a scale splitter.

It also looks like there will be plenty of space for 12s 5000's in the nose, and plenty of room in the fuse to move the fan forward or backward to balance.
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Old Feb 12, 2012, 03:29 PM
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Sugar Grove, IL
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They are not heavy for the size, and the wing area is huge. They are designed to fly with a 60-90 nitro so propped I could see them flying around 60 or so miles per hour. That 120mm fan ought to be able to get it moving.
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Old Feb 12, 2012, 09:20 PM
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Got some more done today. I cut in the other intake and gutted the fan area of the fuselage. I also went to Lowe's and got some styrene to add in places where it is needed. One picture shows where some styrene will be added to make up the walls of the intake. I also figured out that with the batteries in the nose the fan will have to be very far back in the fuselage to balance, too far back for my liking. It looks like I will be able to fit the batteries in right next to the fan after carving out some foam from the sides.

Anyone know what kind of sandable filler works well with Styrofoam?
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Old Feb 12, 2012, 11:27 PM
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Sugar Grove, IL
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If you are glassing it, then I usually just go with lightweight spackle from the hardware store. The stuff is dry enough to sand in 10 minutes and sticks well. I am interested in two things mostly from this build. One, will you just build formers for the rear thrust tube area that you will be hogging out? Two, what do you plan to do to form a clean nosecone? All four of mine have small bb sized holes and duct tape holding the control surfaces on. Yes they were used. Is yours a "new in box" version?
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Old Feb 13, 2012, 08:50 PM
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Thank you for the advice. Have you used lightweight spackle on this kind of foam before? I had thought of that but didn't know if it would stick to the foam.

At this point I am not going to put any formers in the fuselage. The only reinforcing I plan on doing is a 1/4" square hardwood spar in the wing and horizontal stab. I figured the fiberglass would provide plenty of rigidity. I will also use a mylar thrust tube so I just need the hogged out portion to be big enough to pass the thrust tube.

For the nose I just plan on gluing some foam block where the void is and sanding it to the desired shape. I am starting to really enjoy working with this foam as it is very easy to shape with sanding paper.

Yes, mine was "new in box" and had not been shot up. The control surfaces on it were held on with duct tape as well, and I still have the original tape on the elevator . Right now I plan on using pin hinges for the control surfaces.
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Old Feb 14, 2012, 12:25 AM
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Sugar Grove, IL
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I have never seen foam quite like this so the only way to see if it works is to try it. It seems to hold to eps, epp, and epo and will harden rock solid. It's so easy to sand during the curing stage that most of it can be done with your bare hands or fingers if they are calloused enough otherwise 400 grit works well.
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Old Feb 14, 2012, 12:45 AM
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Sugar Grove, IL
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A Video

Here is a video of a guy flying one with a brushless outrunner and 12" prop. Got a great presence in the sky

mig27 4th flight test (3 min 47 sec)
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Old Feb 16, 2012, 10:47 PM
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I got a little done this afternoon. I basically finished the intake shape on the portion still left on the cockpit hatch. I am well above 100% FSA now but I'm ok with a little inlet drag. Any smaller and it would be difficult to glass. Next I need to figure out how I am going to attach the wing and where the servo wires are going to go, then hog out the fuselage part of the wing for the upper part of the inlet ducting.
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Old Feb 17, 2012, 01:11 AM
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United States, SC, Charleston
Joined Mar 2007
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Awsome stuff Scatsob! I saw one of these Mig-27's at an RC swap meet a few years back, God allmighty I wanna shoot myself for not buying it, If they would only build a Convair 990 or Delta Dart atrget drone as well Lol

Great work Scat!
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