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Outdoor Free Flight Forum => Peanut Scale => Topic started by: Tyrannt on November 23, 2018, 11:31:52 PM

Title: P-51 fsw
Post by: Tyrannt on November 23, 2018, 11:31:52 PM
Hello everyone.  Hope things are going great.

I have been wanting to build a p-51 mustang for awhile now.  The other day I came across the plans for this mustang from Pres Bruning.  All the voices in my head said build it, built it, built it.  I listened to those little voices and printed out the plan from the building gallery.  ( A big thanks to Ratz and Sundance12 for this great website.  I have learn alot from here.). I used the poster feature on the computer and made two copies.  One, I put together for plans, and the second for parts and notes.

A little history on this plane.  In 1945 in a quest for more maneuverability.   North American decided to try a new wing design.  The mustang was chosen for the new wing.  In the wind tunnel tests it was discovered that the rigid aluminum wing was flexing asymmetrical, with loss of control.  They then discovered that the wing had to be reduced to a 15 degree sweep.  Testing quit soon after, and no planes were ever built.  The mustang was to have a propeller on the front with a jet engine in the body.

Now.to the build.  I used the second copy of the plans and cut out all the parts.  I then glued them on balsa using a glue stick.  Slick trick that I will use again.  The wings I changed to a cracked ribs set up.  This resulted in a thinner wing than the plans.  This also changed it from a symmetrical airfoil to a flat bottom airfoil.  Hope this works.

The tail feathers went together fast.  Did find one problem with elevator.  The plan shape is about a 1/4" bigger than the side view.  This causes a problem with it sticking out past the fuselage.  The easy fix was to notch the elevator.  (Scrap balsa to the rescue.)

The fuselage was little more tricky for me.  I build the sides over the top of each other and that went well.  When I put the bulkheads in place I learned that therd was no f-7 bulkhead.  I moved f-8 and f-9 forward and that solved the problem.  The other thing I had trouble with was the bulkhead rested on top of the fuselage sides.  If I do this again I will build it with balsa stringers in-between the sides then add on the bulkheads. (On top of the balsa stringers.). I decided to leave off most of the stringers.  The space between was small and the tissue would follow the bulkheads around easily.

One small note, I am planning building with the landing gear up.

Title: Re: P-51 fsw
Post by: p40qmilj on November 24, 2018, 11:21:18 AM
 ;D ;D  i did a plane like that  fsw using sw on elevators.  called it MIGHTY MOUSETANG.... HERE I COME TO SAVE THE DAY!!!

actually I've had several fsw wing designs.  a modified cloud tram as a canard with fsw, the heinkel p1076 (see LUFT46.com)  so this is fun.

jim  ;D

Title: Re: P-51 fsw
Post by: PB_guy on November 24, 2018, 01:07:55 PM
Interesting design. I like strange-looking designs. Hope it flys well for you.

Title: Re: P-51 fsw
Post by: lincoln on November 24, 2018, 02:06:06 PM
Wondering what the stall is like and what's the correct wash in or out. I suspect wash in may be appropriate.

Title: Re: P-51 fsw
Post by: Tyrannt on November 25, 2018, 12:56:24 AM
Thanks for the encouragement.  Some of my favorite planes are canards and forward swept wings.  One day I want to build the x-29. 

Lincoln and p40qmilj, I have been thinking along the same lines for a couple of days, about wash in or out.  One thing that might help, is the huge amount of dihedral.  The original P-51 model had alot.  It's up to the top of the fuselage.  Any advice on this would be of great help.

Right now I am working on covering the wings.  Will post some pictures soon.

Title: Re: P-51 fsw
Post by: piecost on November 25, 2018, 05:17:11 AM
Thats a cool model. Aft swept wings tend to tip stall.and forward swept wings root stall, so it should not need washout.

Title: Re: P-51 fsw
Post by: Tyrannt on November 25, 2018, 09:21:15 PM
Thanks piecost.  I remember hearing that as soon as I read it.  I was relieved and feel much better now.

Title: Re: P-51 fsw
Post by: Tyrannt on November 27, 2018, 03:21:27 PM
I have been pretty busy lately and haven't had any time to work on my mustang.  I thought you might like a small teaser.  I have the tail feathers covered.

Title: Re: P-51 fsw
Post by: charlieman on December 07, 2018, 01:11:43 PM
Could it be you are modeling the nearly unknown photo reccon variant with fsw's and visually disruptive "dazzle" cammou livery?

I suspect that particular design could be flown as a canard, much like a backward flying Gee Bee I saw, with pusher prop?

Title: Re: P-51 fsw
Post by: Tyrannt on December 08, 2018, 09:02:34 AM
Your correct Charlieman.  I am modeling the forward swept wing mustang, with the dazzle camo.  Nice catch.

It been fun but it's been a challenge on the dazzle camo.  I  have been doing all the dazzle camo in tissue.  I covered the plane in white tissue and then put the black spikes on with thinned white glue.  The wings have been a real challenge.  I drew up the camo scheme on paper and then realized that the camo goes only on the bottom.  I had to mark the spots it was to go then lift it up in the air and mark the correct directions to get it right.  Then add the tissue spikes. Still have a few to go but I have to put it all together to get them to match on the bottom of the plane.  With the forward swept wings.

Since the mustang never made it past the wind tunnel testing stages. It probably should be silver, but silver kinda scared me.  I decided to try something different and was looking at coast guard colors when I found the dazzle camo.  It felt right to be on the forward swept wings of the mustang.

The picture, is of the original P-51 trial.   In 1942 they tried the dazzle camo on one mustang.  It worked really well.  The drawback was in keeping the camo paint right all the time.  It gave the ground crews nightmares, and was never put into service for that reason.

Title: Re: P-51 fsw
Post by: Tyrannt on December 08, 2018, 09:37:50 AM
Here are a couple of quick pics.  Nothing is glued together yet.  The wings are holding the body up.  Hope you like.

Title: Re: P-51 fsw
Post by: piecost on December 08, 2018, 11:58:04 AM
Making good progress. I love the dazzle finish.

Title: Re: P-51 fsw
Post by: Tyrannt on January 11, 2019, 03:45:19 PM
Want to say thanks for the support and encouragement.  I know it's been a while since I posted, but I haven't had alot of time lately to work on my mustang. 

I did make a plug for the canopy.  I went faster than I thought. Don't know why it's scared me.  (I have never made one before.  Always stayed away from them.  Flat windows, open cockpits, that kinda thing.).  I put my plug one top of two 16 penny nails I had hammered in to a base.  I pulled two canopy's.  The second one came out ok.  I decided to try again and did two more.  The fourth one turned out really nice and tight to the plug.  It's  still on the plug so I can get a picture of it.  When I went to move it I grabbed the plastic under the plug and heard a poping and crakle kinda sound.  I realized that the plastic is really thin.  My question is how thin is too thin.  I have always used the canopy from kits and they were always much thicker. 

Oh,  want to do another first for me, put a pilot in the plane.  Any suggestions on how to put one in and who it should be.

Title: Re: P-51 fsw
Post by: Tyrannt on February 12, 2019, 03:20:45 PM
Hello everyone. 

Well I made pulled the canopy off the plug, and to my surprise I think was actually really stable.  All along the plug it's a little thicker.  Under the plug it got real thin.  I cut it just a little bit bigger than I needed, and used the excess for glue to the side of the fuse.  Found some real good glue to attach the canopy with. Aleene fast setting Crystal clear gel.  I put a little drop on a scrap piece of paper and used the pointed end of a bamboo skewer to put a small bead of glue down.  Just worked it around the canopy from front to back.  Easiest canopy I have ever done.  When I took some pictures I realized I had pulled the canopy to one side a little.  Going to leave it alone, not worth trying to fix.  Still need to wrap the canopy with green tissue.

On the pilot, I just traced the pilot from the plans.  Then using a small work light I just redrew it on the other side. (In the air. No light box.) It amazing to me how much that little detail adds to the over all plane.

I also built a jig for the wings and tail out of some sheet foam.  It worked pretty good.  Helped big time on the wings.  They were a little tricky being forward swept and with the dihedral.  Still need to glue on the rudder.  Before I do that a have to finish covering the top.  It goes in green.

Title: Re: P-51 fsw
Post by: Tyrannt on February 12, 2019, 03:26:44 PM
Forgot to mention about the naca ducts on the side of the fuse.  I cut out the tissue to size in the black.  I then glued it to the white and recut it out again.  I did this because I wanted to show off the ducts.  From a distance the white kinda disappears, but makes them stand out.  This was a test and I hope it worked.  I will as afraid if I didn't do some thing they would just disappear in the dazzle camo.