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Mig 3

Building and Flying a Studio ‘B’ MiG3 Foamie Combat Sloper
by Marshall Geller

This article shares my thoughts and experiences in building and flying the MiG3 foamie warbird from Studio "B". The information is geared to those individuals who may be curious about foamie construction techniques and/or those who may be contemplating the purchase of this kit.

Instruction Manual

The instruction manual for the MiG3 is written in a similar style as other Studio ‘B’ manuals. The manual presupposes you know a thing or two about building a plane and is not geared to the raw beginner. It often tells you to complete a step but doesn’t give you the specifics on how to do it. That’s where your prior experience or that of a knowledgeable friend will be helpful. It does, however, have some helpful diagrams and some nice graphics. Despite this, I still found myself contacting Lex at Studio ‘B’ for further clarification on a few of the assembly steps. BTW, if you need clarification on some of the instructions, Lex is at the other end of your keyboard and responds to his e-mail very promptly. I have never seen such a high level of customer support from a vendor!

Completing the Wing

The first step is to remove from the wing cores, the threads of melted plastic that remain from the hot wire cutting process at the factory. For this job, I have a wiry scouring pad that works well. A dry sponge also can be used for this task. Be sure and wear a mask, as you don’t want any of the the tiny fibers of EPP foam going into your lungs. They are nasty!

After cleaning the cores, it is on to gluing the spars. There are two spars (for extra strength) and CA is used to glue together the splice in each spars. I like to CA some carbon fiber over the spar slices for good measure. Next, the spars are glued into the spar slot in the wing and the the wing roots (center joints) are glued together. I actually prefer to do this as two separate steps. First, I glue the spars together, using 15 or 30 minute epoxy. After that, I put wax paper around them and clamp them (ordinary stationery binder clamps work just fine) every two inches or so and let it dry overnight. The next day, I remove the clamps and wax paper and then coat each spar, spar slot and wing root with epoxy and pin and tape the wing into place,over the wing core beds. (Line the beds with wax paper first - in case any of the epoxy gets on the beds, you’ll be able to easily remove the cores from the beds). I then let the whole wing dry overnight.

The next step is to cut the trailing edge of the wing to approx. a 45 degree angle. This step is necessary so the plane can fly unballasted in high winds and still penetrate. The instructions here, in my opinion, could be a little clearer here. Fortunately, this same step was also performed in building the Foaminator wing, and at that time, I asked Lex how do I achieve a 45 degree angle. The answer was to measure approx 5/16" from the trailing edge (at the root and tip) and draw a line along the bottom of the wing. Starting on the bottom of the wing, cut along this line at an angle to the trailing edge of the top portion of the wing. I also like to put a strip of masking tape along this line as a cutting guide. Sounds a lot more complicated than it is, but there is a picture in the manual that shows you how the angle is supposed to look after you perform this step. I used a new single edge razor blade for this step. It’s hard to get a nice straight line - mine is a little wavy here and there, but that’s ok, since the fiberglass tape and the aileron hinge will cover this area.

Covering the Wing with Tape

First spray the cores with some 3M 77 adhesive and let it get tacky for a minute or two. This is necessary because the tape will not stick to EPP foam. (It’s a good idea to have some paint thinner close by as the 3M is bound to get on your hands and comes right off with a little thinner). Using 2" fiberglass reinforced strapping, lay 2 full length pieces of tape lengthwise over the spar area, from tip to tip. Overlap them about ½" over the spar. I recommend taping THE TOP OF THE WING FIRST, then the bottom and don’t stretch the tape.

After the spar has been covered, it’s time to cover the rest of the wing. First, starting at the LE,fold a piece of tape over the entire span, so that half of the tape is on the top of the wing and half is on the bottom. Then do the TE the same way. Next, wrap a piece of tape spanwise around each tip. Be sure to cover any remaining exposed wing areas with a strip of tape.

Covering the Wing with Ultracote

Instead of spraying the taped wing with 3M 77, here is a little tip I learned from Dave Sanders of Dave’s Aircraft Works. Sand the tape with 80 grit sandpaper to remove some of the release agent on the tape. Then apply your Ultracote with a 350 degree iron and voila! It sticks.

Sanding the Fuse and Locating the Gear

The fuse in the kit is kind of square in appearance and I really wanted the MiG to look right, so I took my time to round off the corners of the fuse and do quite a bit of shaping. The fuse is made from the heavier density 1.9 LB EPP foam and seems quite rigid and tough. Using 80 grit sandpaper on a sanding block, I kept sanding away till I got it just right. It was a painfully slow process, but after several sanding sessions, I finally got it looking good. Yes, it is quite tedious, but I think it is time well spent (and don’t forget to wear your mask!).

One of the nice things about the MiG kit is that you have a lot of flexibility in terms of how you want to set it up (there are no cutouts for the gear in the fuse). To get the correct CG, you need to temporarily mount the wing and tail surfaces. This requires putting some slots and notches in the fuse for the horizontal and vertical stabs. Then tape your radio gear and pushrods to the outside of the fuse. The idea here is that you are trying to determine where everything will have be located to achieve the proper CG location. Mark the underside of the wing with the CG location per the plans and using a CG balancing stand,(the instructions show you how to build one in case you don’t already have one) put the plane on the stand. Move the components around till the plane balances at the CG. I found this step to be quite tedious, but after a lot of trial and error, I got it pretty close. After you get everything located, draw outlines of the components on the fuse, with a permanent marker. I made the initial cutouts in the fuse with an Exacto blade and followed that up with some cuts from a NEW fine tooth hacksaw blade. I enlarged the holes using a dremel tool with a router bit. I also discovered that a dental pick is useful tool for removing foam from cavities. Some 60 grit sandpaper, wrapped around a popsicle stick, can be used to clean up the holes and make them nice and square. T

here are numerous possibilities for setting up this plane with either two or three servos and the manual discusses several options. I elected to build the MiG3 with two standard Cirrus CS-70 servos in the fuse (aileron and elevator), HiTec micro 535 receiver, 800mah battery and switch. I was trying to keep it light and it came out at 26 ozs. It needed 1.5 ozs of lead in the nose to get it to the recommended C.G. location.

For aileron controls, I used the flexible nyrods (included in the kit). I buried the rods as much as possible in the fuse to minimize flexing and then exited them out the sides of the fuse. For the elevator pushrod, I also used the flexible pushrod supplied in the kit. In order to install this pushrod, I had to make a goove in the side of the fuse, from the servo to the tail section. To do this, draw the pushrod location first, using your permanent marker and then using a small soldering iron or dremel router bit, cut the goove.

Once all the compartments have been cut and passageways for the control rods have been cleared, it’s time to temporarily install the radio gear and check all the hookups for proper motion and binding. This took me some time to accomplish, but you really need to do this now, before you permanently install anything! Once you get it all working, install the outer tubes permanently, with some Shoe Goo.

Taping the Fuse

First spray the fuse with 3M 77 and let it get tacky for a minute or two. On the bottom of the fuse, from nose to tail, lay a 2" strip of packing tape and smooth it down. Then do the same on the top of the fuse. Next, run some tape strips along the sides of the fuse, from nose to tail. The idea is to cover the entire fuse with a single layer of tape. When you are done taping, cut the tape away over the compartments for the servos, battery, switch. It will also be necessary to cut the tape away from the wing slots and vertical and horizontal tail mounts. After this is done, a strip of tape is wrapped around the fuse in front of the wing slot as well as behind the wing slot.

Installing the Radio Gear

I installed the servos using an adhesive called PFM. I really like this stuff much better than the Shoe-Goo I used in building the Foaminator. The PFM is a lot thinner and easier to apply. It also can be removed (if necessary) without too much difficulty. I understand that Household Goop is similar to PFM, but I never personally used it. Because of the location of the aileron servo and the lack of accessing it, I attached the control rods to the servo horn, BEFORE I glued the servo into the fuse. The receiver was mounted vertically in the fuse with the antenna coming out the top. I cut a slit in the side of the fuse and simply pushed the antenna into the slit. The slit ran all the way to the tail section, under the tail and around to the other side of the fuse. The battery was simply placed into it’s compartment, as was the switch. It’s a good practice to make all the compartments as tight fitting as possible. Additionally, I like to make hatches for the battery and receiver compartments. That way, if I have to get into these areas in the future, it is a lot easier. The hatches are made from EPP and have packing tape wrapped around them to make them sturdy.

Double check that all the control surfaces are as they should be and they are not binding. I like "Big Throws", so I set all the surfaces to 3/4" travel, up and down. Put the plane back up the balance stand,do a final check CG check and adjust as necessary. After this, its time to cover the fuse with Ultracoat. It was cumbersome to cover the fuse with Ultracote, since I had previously glued the wing into the fuse. I also found it difficult to use the iron to ultracoat the coroplast tail surfaces, without ending up with a lot of bubbles on the surfaces. I have heard good results about another method involving spraying the tail with some 3M 77 and laying the ultracoat on top of the tail surfaces or using some adhesive backed thin vinyl. The MiG was finished in cocoa brown ultracoat, with olive camo markings and really looks sharp.

Flying the MiG3 Foamie Combat Sloper

Well, I finally got a chance to test fly my new MiG foamie this past weekend. Wow, what a plane! This thing really smokes!! I have flown warbirds before, but none of them fly like the MiG. At 28 oz (with 1.5 oz of lead in the nose),it is very responsive in pitch and VERY RESPONSIVE to roll inputs. I had to switch to dual rates for the ailerons to keep from over controlling. This really surprised me, since I had been used to flying a Foaminator with really big throws! However, this is nothing like flying a Foaminator. The comparison is like going from driving a Honda Civic to a Z-28 Camaro! The MiG was rock steady and had an incredible speed range! All I had to do was drop the nose a bit, and it really picked up speed and moved out! In no time at all, I was doing high speed passes, three feet over the hillside. I was astounded! And when the lift died down, I was amazed to find I could still fly in fairly light lift. It seems to be able to fly in lighter lift than the typical warbird. However, you do need a little more lift for flying this bird, compared to a Foaminator. I was the only one out there flying, so I can’t give you any report on how it does against other foamies in combat. The flying wings seem to dominate the "furballs" we have as contests here in Southern California. But, if you were thinking about what to get for your next plane, or are moving up from a Foaminator like I did, you may want to consider the MiG. For a foamie, this thing really cooks! And it looks very cool too. It is, in my opinion, one of the best kept secrets out there. Lex is got a real winner with the MiG!