mcarleno

Christmas tree most of the day, taking care of sick children, sick wife, sick father-in-law, and now I've got a fever of 102! I little work tonight. I got the forms sliced for the wing and the canopy. I added my carbon fiber tubes (close to scale), added the rear win hold down (I'm torn between a single wing mount, or plug-ins).

Going to bed with lots of blanks and plenty of Motrin!

mcarleno

Some work on the wing tonight. The wing still has some tweaks and will be laid out probably in 2D. But I laid it in the 3D model for reference. I am using Profili for the wing layout. I registered it tonight so I will be able to export the DFX drawing.

mcarleno

Well I re-did the wing this evening with the DXF export from Profili. Then rotated and sized the airfoil sections. The 3-view has an incedence of 2 degrees at the root and I added washout at the tip of 3 degrees. So this means that the tip has an incedence of -1 degree and the root +2. The wing also has 8 degrees of dehedral. I added the foil sections for the vertical and horizontal stablizers. So everything looks good in 3-D and looks like it will fit.

Also had a great discussion with Mike of Redstar RC this afternoon. Discussed the Mig and their new LaGG-3 which is on final after a minor wing redesign. Boy, you want to talk about an awsome job on a 60-90 size plane! I can't wait to get my hands on one of these.

You know that so many of us here talk about the disappearence of kits and manufactures. But we all have to do our part at actually buying those kits if we want them. I see so many recomendations for 1st warbird kits pointing people to the GP P-51. Great plane, but how many people at your field have a mustang? Now how many have a Yak-3? Great first warbird, beautiful plane, awsome laser cut, fast build. Remember 30,000+ Yaks where built and they were more than a match to their luftwaffe conterparts.

Anyway, now that everything looks like it going to fit, I going back into 2-D to layout the formers and ribs with lightening holes and placements. I kinda started this build with sharing and getting some help. Would like some feedback or help on where to go next?

mikeperik

Marc,

You were able to layout the wing ribs in Profili? I need to spend a little more time with it then because I got to the dialog with all of the options on it and my eyes sort of glazed over and I shutdown the program. I couldn't figure out how to size the ribs with the wing being tapered. Did you measure the size in your 3D and transfer the lengths to Profili?

Mike

mcarleno

We sort-of. I stretched the 3-view to the correct wing span. Then on the leading and trailing edge extended the lines to the body Rib and out to the outside of the ailerons (just before the wing tip). I measure the body rib as the root and the outside aileron as the tip. I then worked with the swept until by measure the amount by placing parallel lines from the root LE to the tip LE. I added a 2 degree root incedence and a -1 degree tip. I decided to go with Clark YH all of the way to the tip (a little thicker than the Clark YH Mod that the original had). I allowed Profili to add ribs (13) evenly spaced, I then measured the distance to the dehedral line and found that nearly 5 ribs were placed there. So I measure the distance to the dehedral break and divided by the number of ribs to be placed there (5) and then manually set the rib spacing from 1 to 5 to be this new amount and then allow Profili to auto calculate the remaining space.

I then ran the wing management to print the ribs but could not export them because it kept crashing. So I exported my desired airfoil as a DXF (Clark YH). I took the measurements at the location the Profili had produced for the spacing and in TurboCad to my DXF airfoil and sized to the correct size on the wing form. Once this was done, I started at the root rib and rotated the rib +2 Degrees and step each rib down by .25 degrees to the tip (twelve steps = 3 degrees from +2 to -1). Now, the center ribs are a little closer so they will produce more washout quicker, but only to the dehedral break where the wing bends so I think it will be fine.

I used a NACA 63A010 foil for the stablizers. Don't know much about this airfoil but appeared to be a pretty good symetric foil with the camber back deep in the cord.

Chad Veich

My Feedback: (60)

Guys, lofting ribs for a straight taper wing in a CAD program is a fairly simple matter if you have your root and tip airfoils drawn. You can loft any number of intermediate ribs at any spacing you want and with any amount of wash out. I think Dave Platt's videos have a good tutorial on lofting which he does by hand. The tools in a CAD program make the same process much, much faster. If there is interest I will try and work up a quick and dirty tutorial on how I do it. The Yak-11 I'm working on has the exact same Clark YH at the root and a modified YH at tip as well. (as do the Yak-3/7/9 and probably others) I guess the Russian designers must have been happy with the airfoil!

mikeperik

I for one would be interested. Sometimes a picture make things very clear.

mcarleno

Chating with Mike from Redstar, he had the original LaGG-3 from specs he had as being different than the Clark YH (i can't remember what he said it was), anyway they lost their prototype coming in on an approach low and slow in a right bank and bam-- a quick snap roll in the opposite direction into the trees! They work with some "expert" recommended by the guys at RCSB in South Africa who helped redesign the wing. They are now using an Selig 8036 (this is what topflite uses on the P47 and P51) with washout. I have heard that the Clark YH has pretty good Renolds numbers for a model (though the S8036 is better).

Katchmarek

My Feedback: (29)

Me too!
Rob

Chad Veich

My Feedback: (60)

Test post, just to see if the image is clear. I am working on a lofting tutorial but I will start a new thread for it rather than cluttering up Marc's thread.

flybug

Hello Marc,

Merry Christmas to all, just thought of touching base to see how this project is going.

Keep us posted

mcarleno

Well I finished moving most of the body from 3D to 2D and got everything scaled. I got a big 20cc 2S for Christmas and after playing witht the engine, there is no way to get it in the nose without seeing it. I think the only engine would be an RCV SP but I know these guys run very hot. Anyway, I decided that a 90 would handle the Mig-3 at 1/6th scale (67" wing span), but with the bigger engine, I decided to increase the size a little since I hadn't cut anything yet. So I scaled it up to handle a 5" spinner which puts the wing span at about 77" which makes it about 1:5.75.

I ran a scale of X, Y, and Z in TurboCAD and it was done. I printed out the formers and the doublers. Most of the formers are going on doubled 3/32" balsa (cross grain) with a couple on the wing being birch ply. The Body and wing saddle are lite ply. The nose I am going to carve out of 1/2" balsa and may do a fiberglass cowl after that.

I spent about 3 hours on the scroll saw and a couple of hours tonight glueing stuff, but here in the beginnings of a plane!

Katchmarek

My Feedback: (29)

Mark, Lookin good! Good move scaling up a bit...bigger is definitely better!

Happy New Year,
Rob / katchmarek

flybug

Outstanding Marc, keep it up[sm=thumbup.gif]

mcarleno

A little more work today (well about 6 hours). Man was the balsa dust flying! Most everything went together just as it was modeled in TurboCAD. A couple of minor adjustments but the bottom of the fuselage is roughed out and off the board. The nose has be rough sanded and formed.

The top of the fuselage is also off the board though I have atleast a good 90 minutes of carving and sanding tomorrow (we'll see how much my wife will let me push it???).

Here are the pictures of the current progress. I guess it's about time that I get the 3-view printed and posted on the wall for reference.

mcarleno

Well it was a little more like a couple of hours of sanding. Got the top of the nose roughed out. After assemblying the top of the fuselage, I am not happy with former 11A (top aft of the rear wing former) and it's fit. I need to redo the former from the the 3-view and compare it to the one that I have. It seams a little wide at the top. I'll do that on Monday when I can print on the laser.

Next it looks like the push rods and control linkages, but I think that I will do the empenage first.

With the top and the bottom together, it's starting to look like a Mig!

mcarleno

Well I spent several hours learning a new program. I ended up punting on Profili. A good program but the things that I wanted to do it kept either telling me I needed the professional version or it would crash. So I switched to CompuFoil which is awsome!

I laidout a planform for the horizontal stabalizer. I imported the Selig airfoil data into it from the NASG database that I wanted for the Horizontal stabalizer airfoil. Gave the specifications for the panel and the number of ribs. Setup building tabs and spar. Done!

I will print these out today and see if I can get the stabalizer done tonight.

mcarleno

Well I have the horizontal stablizer roughed out and sheeted on the top. I am trying to decide how "scale" I want to make this aircraft. The aircraft used two hinges on each elevator and I am a little concerned using just two hinge points (three would be ok). If I use two, I will probably need to make them using circut board and piano wire. Any feedback would be great!

Here is the starboard side before sheeting.

mcarleno

Ok, now that I got the pictures off my camera (had to pull my wireless ....)

Here is the "rough" stablizer with sheeting. Portside is sanded to leading edge. I will sheet the bottom after I decide how many hinge blocks to add. Looking for some feedback on two hinges (scale) or three (pucker factor).

Anyway, here is it sheeted.

mcarleno

Wings-- Spent about 4 hours last night setting up the Planeform for the wings in CompuFoil (very, very cool program). CompuFoil lets you setup multi-panel wings. The first panel is under the saddle at the fuselage. The second panel goes from the saddle to the dihedral break outside of the landing gear. The third panel goes from the dihedral break to the end of the flaps. The forth and final goes out the end of the ailerons. The panel is 33.8" without the tips which are 3.6". This give me a span of 74.8 inches. CompuFoil calculates that my wing area is 888 sq. inches without tips so it should be about 900 sq. inches with them. With a target weight of about 12 lbs. this puts my wing loading right about 30 oz/ sq. foot. Not to bad for a warbird! She should land great with flaps down.

I output the ribs to a CNC-DXF file, but I probably with cut them on a scroll saw though I will get a quote on having them laser'd. Here is all of the output from CompuFoil.

Here is output in PDF for the Wing Plan with ribs -- anyone else want to build one?

mcarleno

Well spent some time tonight cutting and pasting -- Litterally! Cut and taped together the first of the 3-Views for reference to my scale 1:5.4. After I got it done, just had to check the framed fuselage out against it. This is the first time I actually overlaid it since I printed the formers out of TurboCAD along with the placement guide. Though the camera angle doesn't show well, it is a perfect match! Not to bad for firing up TurboCAD for the first time just over a month ago!

Also spent a little time researching tail wheels. The Mig-3 had a retractable fork style wheel, but in the winter of 1942 all new Migs and all Migs in the field had their tail gears lock in the down position (probably because of rough ground conditions and failure problems). The gear doors where removed and coverd with doped tissue. A canvas boot was fitted to help streamline the tail gear. I haven't decided on whether or not to install a retractable tail wheel, but if I go that route, I think this one from Century will work.

It is for a Bates 1:5.3 scale Yak-3 which is pretty close to my Mig which is 1:5.4.

mcarleno

Calling it a night, but here is the detail cockpit drawing view.

Along with some great info available at:
http://mig3.sovietwarplanes.com/mig3...r/rusavia3.htm

mcarleno

Its been awhile since my last post here (wow - nearly 2 months!) but I haven't had much chance to build and have been working on the cockpit.

Well I got some of my stuff delivered today and I just had to make time to play this evening. I've spent all week with kid's baseball (son) and fastpitch softball (daughter), a school field trip on Tuesday and about 75 hours at the office. I got home at 6:30 tonight, ate a Taco Salad (yeh, for Atkins!) and pour a cup of coffee and I disapeared into the garage and pretty much ignored everyone else in the house for "my-time".

Today arived one set of Robart 531Rs, two 4.5" tires, an air - kit, and a 5" inch aluminum spinner. So I decided to see what the spinner looked like on the nose. I've had so little time and the time that I have had has been spent working on the cockpit. So I decided that, though it is still missing a few things, I would get it into the fuselage and take some pictures while I was checking out the spinner. Seeing it like this has really pumped me up and I've been "Jones'n" for some balsa. So hopefully I will find some time to get back on track.

Here is stuff roughed out (stabalizer still needs work haven't done anything to it in over 5 week!).

mcarleno

Over three months since a post. Little League is over (finally -- a lot of fun but with two, not much time for anything else) and I have had some build time. So I thought I would update.

I finished most of the sheeting and roughing (the nose is very rough). Still a little tape holding the last few sheets in place. All of the internal stress connections have been re-enforce with carbon fiber tape. I think the design is going to be good. But I'm thinking at least 15 lbs now. That puts me on the edge of my engine (now broken in) so I'm not going to mount the engine yet until I get a closer to an accurate weight. Might need to move up to a G2300. I could go Gas but for gas I think that I would need to be around 30cc and it will certainly stick out a lot on this plan.

The vertical stabalizer is ready for lightening holes and build up. The canopy is fiberglass and I used the build up to make a plaster plug which I will use to pull the plastic. The fiberglass will be frame. About 10-15 more hours and I will be ready to start on the wing.

mcarleno

It been over a month since my last confession ... oh, wrong context I mean post (though sometimes the same thing).

I've been working in CompuFoil to lay out the wing and ribs. What a great program and for anyone looking at designing a wing, this is a great program. The wing is laid out using a ClarkY airfoil from the NACA airfoil database (selig dat files). Specify the root cord, tip cords, washout, spars building tabs and output much of this data to TurboCad to finish figuring out the landing gear.

The wing came together great with the exception that I spent a good 5 hours on the scroll saw. Though the wing is not joined yet at the dihedral break, its close to getting there.