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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 doesnt give you the specifics on how to do
it. Thats 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 dont 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, youll 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. Its hard to get a nice straight line - mine is a little wavy here and
there, but thats 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. (Its 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 dont stretch the tape.
After
the spar has been covered, its 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 Daves 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 dont 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 dont 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, its 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 its
compartment, as was the switch. Its 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 cant 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!
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