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Jan 05, 2009, 01:32 PM
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vampire67's Avatar
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Build Log

[email protected] design 1/9 Mig 3 build


While [email protected] is still busy with exams (YES YOU CAN ) and his Cobra build for scratch build-off 3 I got a chance of a life time:
kit no #1 (after [email protected]'s No #0) arrived on saturday from Manzano and it looks like I'm now the first one to built it.

Downside is, no plan (yet), no manual and no canopy.

This is what arrived from Charlie. High precission cutting on high quality balsa and ply (as usual).
Last edited by vampire67; Jan 05, 2009 at 03:47 PM. Reason: Category
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Jan 05, 2009, 01:46 PM
Registered User
WHOA didnt know he had a Mig designed. Darn another plane I am going to have to get but the Aircobra is the first.
Jan 05, 2009, 02:09 PM
The wings are not on fire
W@CC0's Avatar
Hurray

Red in the first picture is indeed the for the underwing radiator.
Green is the former on wich you can glue the 0.8mm ply instrument panel. I'am about to draw the instrumets for you so you can print them, cut them out and glue them behind the ply panel.

Second picture
red are the reeinforcements to glue where the servo screws go through the upper part of the box structure. They have to come at the upper side of that part, just in front and aft of the square hole in it.

Blue and green are leftovers from the alpha model (see pics below), wich I don't know if I will use them myself. I left them in cause you never know Blue is the most aft fuselage former, just in front of the rudder. But there is not that much left of it so it is possible that I leave them out.Green is a reenforcement for where the wing bolt goes through the underwing radiator. In the prototype, the bolt to hold the wing to the fuselage is behind the wing through the radiator. I thought it would be better if it went through the wing. So I think I will use only a piece of that part.

3th picture
red, exhausts

blue and green, missing macchi parts, as are the wing sadles in that picture.

I hope to get your plan in the mail on wednesday, just after my exam

Here is a website you defenitly have to take a look at if you're only slightly interested in Mig-3's. It is full of tech stuff and paint shemes etc

http://mig3.sovietwarplanes.com/mig3/mig3.html

Attached are 2 pictures of the very first 'van Haaren' designed plane ever. The Mig that my dad designed and made and where I started from to make this laser cut 1/9 version.

Good luck on the build Peter!

Tom
Jan 05, 2009, 02:16 PM
Charged up and buzzing
vampire67's Avatar
Thread OP

Building begins


As the plan is possibly arriving in a few more days I've considered starting the wing the least risky to do something stupid.

As I'm considering the Mig for a pylon race class I will reinforce the wing a little.
I'm shure the spar is more than sufficiant for normal flying. My RBC La5 has the same wing construction and is more than stable enought. Even used it already for this pylon class (althought under powered for the race).
However I decided a little carbon should help any doubts.
For this I cut a slot along the spar, approx 1/16" wide (1,5x1,5mm) on the lower and upper sides.
The lower side will be filled with carbon rovings while assembling the spar. The upper side has to wait until shortly before the upper sheeting.
While having the "juice" ready I thought a little glass weaves for the shear web would be helpfull too.
Jan 05, 2009, 03:03 PM
Charged up and buzzing
vampire67's Avatar
Thread OP
Hi Tom.

You have still time for watching and posting ?
Back to library studying, don't want to hear we caused you to screw your exams

Quote:
Originally Posted by [email protected]
Blue is the most aft fuselage former, just in front of the rudder. But there is not that much left of it so it is possible that I leave them out.

There are already top and bottom former halves.
You mean an additional former in front of the horizontal stab ?
If I understand the rear fuselage I need to assemble the formers and the stabilisers together with the top and bottom keel parts to align everything correctly ?

Quote:
Originally Posted by [email protected]
Green is a reenforcement for where the wing bolt goes through the underwing radiator. In the prototype, the bolt to hold the wing to the fuselage is behind the wing through the radiator. I thought it would be better if it went through the wing. So I think I will use only a piece of that part.
I thing you moved the bolt hole already into the wing assumed from the bolt hole position in the fuse parts.

Quote:
Originally Posted by [email protected]
Green is the former on wich you can glue the 0.8mm ply instrument panel. I'am about to draw the instrumets for you so you can print them, cut them out and glue them behind the ply panel.
I feared that this is supposed to be the instrument panel The scale thing looks a lot different

You see that I can help myself

While we are at it ...
Have you set the russian on a slim-fast diet.
The cross sections should be a lot wider

Most desperatly I'm missing the square nose section.
Also the turtle deck could get some more straight sides.
I'm realy tempted to modify the formers a little for these "corrections"

I also plan to make an access hatch for the battery.

greetings Peter
Last edited by vampire67; Jan 05, 2009 at 03:50 PM.
Jan 05, 2009, 05:25 PM
The wings are not on fire
W@CC0's Avatar
Quote:
Originally Posted by vampire67
Hi Tom.

You have still time for watching and posting ?
Back to library studying, don't want to hear we caused you to screw your exams
Still some time

Quote:
Originally Posted by vampire67

There are already top and bottom former halves.
You mean an additional former in front of the horizontal stab ?
If I understand the rear fuselage I need to assemble the formers and the stabilisers together with the top and bottom keel parts to align everything correctly ?
Those 2 little things are supposed to go behind the horizontal stabilizer. At the end of the bottom keel.
When building the fuselage, you put all the formers and keels and side stringers in place, except for the top of the former that goes through the stab. You plank the fuselage except for the razorback. Then, stabilizer, top part of that former and then the fin. After that plank the razorback, so it nicely fits with the tail and stabilizer.


Quote:
Originally Posted by vampire67
I thing you moved the bolt hole already into the wing assumed from the bolt hole position in the fuse parts.
Yup

Quote:
Originally Posted by vampire67
I feared that this is supposed to be the instrument panel The scale thing looks a lot different

You see that I can help myself

While we are at it ...
Have you set the russian on a slim-fast diet.
The cross sections should be a lot wider

Most desperatly I'm missing the square nose section.
Also the turtle deck could get some more straight sides.
I'm realy tempted to modify the formers a little for these "corrections"
Yup, vodka diet...
As I said before, it is a slightly scaled(94%) version of my dad's design.
When he drew it, we only had a small top view and a side view, togheter with a plan of a 80cm speed 400 powered Mig. A couple of people asked me to kit this mig and so I did. But I absolutely forgot to make it somewhat more scaleish. Hmm, how do I solve this....

Attached is a drawing wich I used to create the instrument panel. I think it looks like the top side of it. True, there is no revi

Tom
Jan 05, 2009, 05:51 PM
The wings are not on fire
W@CC0's Avatar
Peter have a look at this.

I tried to make a more square nose from the sections we have. In the pdf are the formers I used to get to the shape in the printscreen.

Now I go to sleep

Tom
Jan 05, 2009, 06:07 PM
Charged up and buzzing
vampire67's Avatar
Thread OP
Quote:
Originally Posted by [email protected]
Yup, vodka diet...
As I said before, it is a slightly scaled(94%) version of my dad's design.
When he drew it, we only had a small top view and a side view, togheter with a plan of a 80cm speed 400 powered Mig. A couple of people asked me to kit this mig and so I did. But I absolutely forgot to make it somewhat more scaleish. Hmm, how do I solve this....
Yup, on the Folgore you did a great job to replicate the fuse cross sections. The P39 is rather uncritical, no distinct sectional features.
If you would go to do a second drawing version I would suggest to make the two forward formers a little more edgy on top. It might be helpfull to create an additional former beween the first two as the edge of the engine cover starts there. The structure could be kept completely identical.
The width should be relatively easy to blow up.
I think there is still some "beaf" left on the ply sheet so no added sheets are needed.

Quote:
Originally Posted by [email protected]
Peter have a look at this.

I tried to make a more square nose from the sections we have. In the pdf are the formers I used to get to the shape in the printscreen.
Just the two forward formers should do.
The edgy design was to make room to the V12 engine head.
In front of the windshield it's round again. So I would suggest keeping the "van Haaren" design.

Quote:
Originally Posted by [email protected]
Attached is a drawing wich I used to create the instrument panel. I think it looks like the top side of it. True, there is no revi
Makes sense.
But I doubt the rectancular instrument in the center.
I think this is created after the mockup in Monino.
This mockup has even very doubtfull external features.
However the second row seems to be just some non functional hatches.
Until just a few years ago there were no restored Mig's
On the restored Mig the second row does not exist and the next instrument row seems to have moved up.

I will possibly also remove the cockpit bottom to have more space for scale details.
Also my 1/9 pilot need more height.
(It's self created, if you like it I have several copies left as epoxy or latex versions.

greetings Peter
Last edited by vampire67; Jan 05, 2009 at 06:20 PM.
Jan 11, 2009, 10:00 AM
Charged up and buzzing
vampire67's Avatar
Thread OP

Build continues


The wing gave me some problems.
As the reinforced spar is better to do in one piece I had to find a way of doing the sheeting with the angle of the outer wings. A little makeshift helling was needed.
Sheeting started with a one piece shell. Then spar and ribs of inner section were glued on the normal building board.
After curing I sligthly cut the sheeting (just a little) to allow it to bend at the angle. Outer wings were then done on the helling.

I finally decided to only do a few former changes.
I will have to double F3 and F4 for a battery hatch anyway.
So F2 and F3 got a little more edgy upper halfes.

regards Peter
Jan 17, 2009, 02:01 PM
Charged up and buzzing
vampire67's Avatar
Thread OP
Whoever invented strip planking . . .

It's slow going but the fuse slowly starts to take shape ..

Peter

P.S. Looks like RCG turned the portrait format pictures back to landscape. Any idea how to fix this ?
Jan 17, 2009, 02:42 PM
frenzyscot
Looking good,

Don't know what is this PU glue you are using (the only thing that comes in mind is polyurethane) but it seems you are using plenty? as is more than...

anyways, as far as planking ic, I think there is a steep loving curve there, but it starts with hate , give me anything that I could plank or just plain sheet and I go with planking, follows better the curves and adds more strength for mono or semi monocoque designs.

good luck
Jan 17, 2009, 03:01 PM
Charged up and buzzing
vampire67's Avatar
Thread OP
Quote:
Originally Posted by xterarc
Don't know what is this PU glue you are using (the only thing that comes in mind is polyurethane) but it seems you are using plenty? as is more than...
Yes it's polyurethane based.
The good thing is that it's developing a kind of foam to fill the seams. I still have to work on finding the right balance when applying it

Actually planking is not that difficult but time consuming.
Even on weekends I don't get more than three sessions done per day as the glue needs several hours to cure.
I'm still fiddling with the lower sections. The top will be more interesting as the transition of the round front and back to the square engine cover will make planking realy difficult.
But you are right about the curves. Plain sheeting usually looks a little edgy.

I'm already thinking about how to do the oil coolers in the front sides. The intakes are inserted into the sides so I will possibly need to cut out some section and insert a rolled balsa tube.
Jan 18, 2009, 06:34 AM
The wings are not on fire
W@CC0's Avatar
Looking good Peter.

I use UHU Hart & thick cyano for planking. The UHU for glueing the strips to eachother, the cyano for gluing the strips to the formers. This way you can speed up the planking process. But you have to take care not to spill the cyano on the top side of the strips.

For planking the top-front fuselage, you can maybe make the balsa strips wet, so they bend better.

On the first mig, the side air scoops were made from 2mm thick balsa strips, 5mm wide. They were made seperatly from the fuselage and added when the fuselage was planked and sanded. In the fuselage sides, a large hole was cut where the air scoop fitted over.

What motor are you going to use with the 4s pack?

Tom
Jan 18, 2009, 07:55 AM
Charged up and buzzing
vampire67's Avatar
Thread OP
Quote:
Originally Posted by [email protected]
I use UHU Hart & thick cyano for planking. The UHU for glueing the strips to eachother, the cyano for gluing the strips to the formers. This way you can speed up the planking process. But you have to take care not to spill the cyano on the top side of the strips.

For planking the top-front fuselage, you can maybe make the balsa strips wet, so they bend better.
As said I have a few problem with CA. Recently it takes ages drying so the the benefit is gone for me. Maybe it the dry room air during cold season.

CA and UHU Hart both are a little brittle for this. The PU glue seems to stick better than white clue but also stays flexible. This is what I missed with CA and UHU Hart.
Also the PU is a lot faster than most white clue brands.
Obviously it needs time to get is realy done

Once upon a time there was a better alternative to UHU Hart: east german glue "Duosan Rapid", but it didn't survived the downfall of the wall.
http://www.storyal.de/story1995/duosan.htm
This is the glue I was used to when I started modelling as a boy 30 years ago. There had been no replacement that lives up to that memories.

Quote:
Originally Posted by [email protected]
What motor are you going to use with the 4s pack?
Originally thought about a Kora 20 but they have to low Kv. Possibly I go for a bigger inrunner as I need a 60A setup that runs 200++km/h. A Mega 22/30/2 on a 7x8 seems what I need.

I already hear outrunner xx ...
Checked a few but they don't work with 4s/ +60A. Eigher to low kv to drive a usefull prop with speed or the current is a problem. Usually I would need more than 6s and 10" prop but that also is a lot of drag to overcome.
Maybe the horror outrunners from www.powercroco.de are a solution but I havn't seen something comparable commercially. That guy has also made a speed Ko(b)ra.
Something like this seems needed comercially.

regards Peter
Last edited by vampire67; Jan 18, 2009 at 08:04 AM.
Jan 29, 2009, 04:18 PM
Charged up and buzzing
vampire67's Avatar
Thread OP
Meanwhile I'm making good progress with the fuse and wing.

I realy starts to look like a Mig 3


After having the top closed I couldn't resist to cut out the battery hatch


After discovering a small displacement of the ribs from the plan I opted to increase the ailerons. I also made it a little more narrow. I think it's closer to the real ones now.


A small ply half-circle from the scrap serves as doubler for the aileron link attachment.


Finally closed the center section sheeting.
The carbon band in the rear should make the TE a little stiffer; balsa TEs are normally very brittle when grinded to a thin profile.


The effect of the carbon rovings in the spar turned out to be amazing. I can't bend the wing tips more than 1/10" even by all the force I would have the courage to apply there.

Before sheeting the outer sections I'm currently working on the aileron servo. I have my own home made servo frame.
These frame is glued to the sheeting and the servo hatch is then cut out from the outside. The servo hatch is simple 1/8" ply from the remains of Charly's kit that will be fixe3d with frour screws in each of the corners.

The rear of the fuse is still unsheeted. It turned out to be a littlle tricky and the tail feathers need to be finished first.

I think I found the right motor.
I've opted for a Scorpion HK3026 v2 with 1600Kv.
Initial calculation will give me 60A/750W mechanical and 250km/h prop speed with a 7x8 prop.
Hopefully the tests will find it matching with the real world.
And hopefully I have the courage to get it up to full throttle

Peter


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