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Old Dec 05, 2012, 03:32 PM
Dr John
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Lake Placid, Florida
Joined Dec 2001
2,712 Posts
Build Log
Dr John's MiG-29 twin 28mm EDF

There has been enough interest in this plane since I posted some pics and video to make me decide to go ahead with a build thread for her.

Video here.......

UMX MiG-29 Video (3 min 10 sec)


This kit is available from Dr John's Laser Service (Me). The kit will include all laser cut Depron parts, laser cut ply control horns and all required carbon fiber tube and rod. Also included are two preformed thrust tubes with 85% FSA exits. Wingspan is 15" and the AUW as shown with fiberglassed wings and paint is 147grs. Leaving off the glass and several coats of WBPU would save over 1/2 oz.

She is designed around two 28mm EDFs as found in the Parkzone MiG-15 UMX. She also uses two of the AS3X Rx boards from the same source. If you only want to use one Rx then you will need to mod it to use two matched 5 amp ESCs. I am using three HK ultra micro digital servos with the aileron servos flush mounted in the wings. These servos do require a connector change to be compatable with the Spektrum Rx. If you would prefer to use the standard linear AS3X servos let me know when ordering and I will eliminate the cutouts so you can surface mount them. I am using a custom 500mah 2s 35c Hyperion lipo with dual output connectors so both Rx run off the single battery. These are available from rc babbel here on RCGs.

Before you ask, NO there is not enough room for 30mm fans. The airframe is optimized for the 28mm units. If you removed the intake lips from AEO 27mm fans they would fit but I don't think you could fit enough battery to feed two of those amp hogs.

Kit price is $39.95 + $5.00 shipping in the CONUS. PM me for ordering details if interested.

Thanks
Dr John
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Last edited by pmpjohn; Dec 11, 2012 at 09:32 PM. Reason: add thrust tubes to kit inventory
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Old Dec 05, 2012, 05:02 PM
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United States, IL, Joliet
Joined Jun 2009
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Start the build doc ,iam sighned up .joe
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Old Dec 05, 2012, 05:36 PM
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Chicago, IL
Joined Nov 1999
2,058 Posts
Darn you! I was just thinking I can't buy anymore planes, I need to finish the ones I have! But this looks too cool!

I'm going to follow this build thread, who knows, might have to put another plane in the que.
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Old Dec 05, 2012, 05:37 PM
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First question - looks like the fan & motor are $35, $70 for two, is that correct?
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Old Dec 05, 2012, 07:09 PM
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Australia, SA, Adelaide
Joined Aug 2011
801 Posts
Awesome! Im keen to get a kit, will you be able to post overseas to Australia?
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Old Dec 05, 2012, 07:30 PM
Dr John
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Lake Placid, Florida
Joined Dec 2001
2,712 Posts
Angelo

That sounds about right. I have no control over HH prices. I got the first system out of my first MiG-15. The second fan/motor came new from HH and the second Rx I picked up from a RCG member.

Groovechampion

If you want to pay the frieght I will ship.

Thanks
Dr John
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Old Dec 05, 2012, 08:30 PM
Dr John
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Lake Placid, Florida
Joined Dec 2001
2,712 Posts
Lets get started

First a word about glue. Unless noted otherwise I am using Beacons Foam-Tac for this build. Less is more. It only takes a thin film to get a strong bond. Excess glue just takes longer to dry and leaves a rubbery line to sand. Start with the two parts made of laminations, the nose and the canopy/hatch. Both parts are made of six layers with the center two being different than the two on each side. A thin bead of glue is run around the perimiter and down the center of one layer. Press that layer to the next layer and slide around to spread the glue out thin with 100% coverage. Pull the layers apart and press back together a few times until you get lots of strings between layers and press together. Slide into alignment and do it all over again with the next layer.

The part in the top left of the pic is the canopy and the nose is shown already glued to the main fuselage subassembly and rough shaped. The turtle deck is made of a 3mm bottom piece, two 6mm sides and a 6mm top and go together as shown in the top right with the sides sandwiched between the top and bottom. Note this is shown upside down in the pic.

Before framing up the fuselage subassembly cut a 12mm wide notch in the top front edge of the 6mm floor. This should be cut at a 45 deg angle so it forms an air intake when lined up with the nose piece. Glue the fuselage sides to the floor aligning slots and tabs at 90 deg to each other. Sand the rear edge of the top front fuselage block at an angle to match the step down in the sides and glue into place between the sides. Once the glue has set block sand the front of the fuselage and the rear of the nose flat and square and glue the nose into position.

On a flat waxpaper covered surface glue the two wing halves together and cut a piece of .080" carbon fiber rod to fit the spar channel and glue in. Place weights on both sides of the wing to hold flat while the glue dries. Cut a piece of 1/8" carbon fiber tube so it will protrude about 1/16" past each side at the groove in the rear of the wing assembly and glue in place.
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Old Dec 05, 2012, 08:42 PM
UMs & parkflyers... for now.
davidterrell80's Avatar
United States, VA, Herndon
Joined Apr 2012
2,956 Posts
Sub'd with pleasant anticipation.

Do you use the Foam-Tac per instructions (apply, stick, separate, wait, stick)?
Or, do you use it like white Gorrila Glue?

David
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Old Dec 05, 2012, 09:04 PM
Dr John
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Lake Placid, Florida
Joined Dec 2001
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David

Whenever possible I do the stick, pull, stick thing. It helps the glue out gas faster. In some cases like dovetail or slot and tab joints that is not always practical or even possible.

Dr John
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Old Dec 05, 2012, 09:12 PM
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Australia, SA, Adelaide
Joined Aug 2011
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Great Dr John!!! Subscribed and awaiting till next week to make an order! (Pay day.)

Nath.
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Old Dec 06, 2012, 12:34 PM
Fly it like U stole it
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Champaign, Il
Joined Mar 2008
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THis is great!
I have my order in.






Matt
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Old Dec 06, 2012, 06:00 PM
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South Korea, Chungcheongbuk-do, Cheongju-si
Joined Jun 2009
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That's Great!.
You're control king!
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Old Dec 06, 2012, 09:25 PM
Dr John
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Lake Placid, Florida
Joined Dec 2001
2,712 Posts
Time to do some sanding

After the subassemblies are fully dry tape the ailerons into position on the bottom side of the wing. I use a half sheet sanding board loaded with 80 grit open coat paper and round the wing leading edge and sand a basic airfoil shape into the outter wing panels. Alternate from one side to the other so both panels come out close to the same. Use care as the 80 grit will cut fast once you get through the skin on the surface. Try to keep a nice thick rounded leading edge as that will stall at a slower speed than a sharp leading edge. Roll the back 1/2-1/3 of the wing down to a 1/16" trailing edge to minimize drag. The actual airfoil at this size is not all that critical. Keeping both wings the same is.

Using the same sanding board round the top of the turtle deck. This is much easier to do now rather than after it is glued onto the wing.

Block sand the top and bottom of the nose flush to the top and bottom of the fuselage and to a smooth surface across the part. Block sand the nose sides flush to the fuselage and curve down to a point. Try to stay symetrical and have both sides meet at the centerline. This is a good time to round the corners of the forward section of the fuselage. I use about a 3" square piece of 80 grit free hand for this. Work towards a more and more rounded cross section as you move forward on the nose. Do not try to rush these sanding sessions as the time spent here will go a long way to hiding the fact that this is just a square box.
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Old Dec 07, 2012, 09:15 AM
Dr John
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Lake Placid, Florida
Joined Dec 2001
2,712 Posts
If you look closely at the pics you will see a fine line on the wing bottom at the root and the wing top parallel to and 1/2" back from the leading edge. This is the layer of 3/4oz fiberglass cloth that has been applied to the wing bottom and around the leading edge with WBPU. Fiberglassing is optional. It will add weight but at the same time it will make the plane much more resistant to hangar rash. If you want maximum performance leave it off. If you want something that will look good a little longer apply it. At this time I removed the ailerons, cut a 45 deg taper along the front lower edge and taped them back in place from the bottom. When glassing the top, cover the wing back to the trailing edge of the ailerons. Cut the ends of the ailerons free and you have instant shin hinges. If you are not glassing the wing, use hinge tape to attach the ailerons.

Glue the wing subassembly to the fuselage subassembly. There are tabs and slots to ensure these parts are in proper alignment.

Glue the turtledeck to the top of the wing. Make sure it is tight against the cocpit sides and centered on the wing. Flex the rear edges of the cocpit sides in so the inner surface is flush with the inner surface of the turtledeck at the top, pin and glue. From a scrap piece of 6mm foam cut and fit the shelf shown at the rear of the cocpit opening. Sand the exposed part of this shelf so it is parallel to and 1/16" below the edge of the cocpit sides. This will hold a magnet as part of the canopy hold down.

Glue the four 2mm ribs into the slots provided on the top of the forward wing strakes. The larger rib should be tight against the cocpit side.
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Last edited by pmpjohn; Dec 12, 2012 at 07:34 PM.
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Old Dec 07, 2012, 12:31 PM
Dr John
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Lake Placid, Florida
Joined Dec 2001
2,712 Posts
Sand a bevel on the bottom outside and rear edges of the 2mm strake skins. Glue these into position over the ribs with the outside edge flush with the leading edge of the strakes. These will need to be pinned and taped to hold their shape until the glue dries. You will end up with a small gap between the skins and the cocpit sides.

Time to break out the lightweight spackle. There are several brands of this and they all work the same. Just be sure it is the lightweight stuff. Add a few drops of water onto the spackle and stir a small area until you have a puddle thinned to the consistancy of thick cream. Keep a bowl of water nearby during this step. Using mother natures best spreading tool, a finger tip, build up a fillit of spackle along the joint of the cocpit side and strake skin. Also fill any gap between the cocpit side and turtle deck. Feather the trailing edge of the strake skin onto the wing surface. Smooth the spackle with a wet finger (bowl of water). Build a small fillit of spackle along the turtle deck/wing joint. When dry sand with 220 grit paper. Plan on more than one round of spackle on, sand off until everything flows together smoothly. Using a very wet finger and a small amount of spackle work the spackle into the surfaces of foam were the surface skin of the foam has been sanded through. This will include the nose block, entire turtle deck and rounded corners. Again do not rush this procces as the effort here will greatly effect the final outcome.
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