New 46 sized P-47 design

[Pat Johnston]

Stunt Hanger got me excited last week about a 40 sized P-47, so I started with the outlines of my Brazilian P-47 design and shrunk it down to a 40/46 size.  It came out at 579 squares.  I made it a little larger than my usual 560 inch planes (Brodak series) because the rather fat fusealge takes a bit of a bite out of the wing area.  This little trick makes it in the effective range of a 560 incher.  I'll attach PDF files for most anyone to be able to open and look at.  With a good selection of light wood (see National Balsa for Contest wood and specify at least .060" for 1/16" stock) and reasonable care on finishing, there is no reason this little beastie should not end up in the 40-45 ounce range, and be a great flyer.
I did take a little departure from my usual airfoil by incorporating one similar to the High Performance Ringmaster series and +P Combat series.  This airfoil is a pure ellipse on the front 20%, transitioning back to the trailing edge with a straight line, tangent to the ellipse.  It has proven to be successful beyond all our expectations.
There is another little trick on the fuselage construction.  The front 13 1/2 inches of the sides are made of 1/4" balsa, which is spliced to 3/32" stock for the last 2/3 of the fuselage sides.  This little trick allows a person to shape the front nose section to very round and scale-like sections.  Notice that the sections do not look like the fuselage has been put in a vice and an inch and a half has been squeezed out of it.  Overall, the realism of this design is very scale-like while retaining the good qualities of a top stunter.
Enjoy gandering at the PDF files.
Pat Johnston
Idaho Design Division
Skunk Works

[FLOYD CARTER]

That's sounding pretty good.  I'm not in the market right now, because I'm already starting a semi-scale Spitfire. I'm curious about splicing 1/4" sheet to 1/8" on fuselage sides.  I'd be interested in incorporating this on my Spit, but not sure how to do this while maintaining structural integrity.

Floyd

[Ron Merrill]

Hey Pat, when available, let me know, i want set of plans for the Brazilian and the .46 size one. Got some time to build. Ron.

[Bill Little]

As usual, Pat, it looks real good!

I do have a question related to this (and some other designs):  You call out using beaded foam for a buck for the cowl to lay fiberglass over.  Now, what tools do you use to shape the beaded foam?  "beaded foam" is aggravating for me to work with, but I am not probably going about it with the right tools......  

Thanks!
Bill

[david beazley]

Pat, looks cool!  Any laser kits in the future?

[Bill Little]

Pat, looks cool!  Any laser kits in the future?

Hi David,

Not Pat, but I know he can laser cut you ribs, and any other other parts, too.

Big Bear

[Pat Johnston]

You are right, Bill.  I am a bit behind on getting orders out, but I will be setting up cutting files for the Ribs and Formers for the P-47.  The rest of the other parts are pretty easy to manage for most all.  I suspect costs will be $28 for the Ribs and foir the formers.  I'll haveto see what it takes to get them on a cutting sheet.  The problem is that they are so wide that many will need to be split in two and spliced together.  I'll get back on that next week when the cutting file is made up.
For whittling the fiberglass cowl, I mostly use the fat X-acto handle with the long straight blade.  I sharpen the edge so it is razor sharp and pretty much shave the foam as I cut it.  That is the top secret method.
Pat Johnston
Skunk Works

[wwwarbird]

For whittling the fiberglass cowl, I mostly use the fat X-acto handle with the long straight blade.  I sharpen the edge so it is razor sharp and pretty much shave the foam as I cut it.  That is the top secret method.
Pat Johnston
Skunk Works

 Huh? Am I stupid or what? Looking at the plans the cowl looks built into the balsa structure to me, not fiberglass.

 If I may offer two cents I think it looks great overall, but the nose really begs to be more rounded all the way around from what would be the full scale firewall line forward. This would greatly enhance the scale look. Like the unmistakable P-47 wing outline, that big cowl and it's proper shape is a big part of what makes a P-47 a P-47, and not just another morphed T-Rex. What I do is take a true scale outline and lay it over the "plan" and work out the comprimises.

 Sorry, just attempting some constructive criticism. Or would this be PRE-constructive?

[Bill Little]

Hi Wayne,

If you blow up the section right under the nose on the fuselage side view, it tells of laying up a fiberglass cowl.  Two layers of .6oz cloth and a cover layer of 2oz. cloth.   It can be built like the rest of the fuselage of course, I was just wanting some of the "secrets" of making that buck out of beaded foam which Pat describes.  Cutting and shaping beaded foam always makes me ill......

Bill

[wwwarbird]

 Aw c'mon Bill gimme a break, I would have to know how to operate my computer to have seen that detail.

 Got it now though.

[john e. holliday]

Hey Pat,  I printed off the little plan file for the P-47.  A lot of parts to be cut and if you get the price set for all of them I may have to mortgage the house to get them.   The wife already says I have too many planes.  I keep telling her I need the planes for the engines I have.  Found another LA 46 that needs a home.  The Fox I am playing with has issues.   Bigiron made me a venturi set up for it, but I think I have tank problems.  Have a rectangle clunk I am going try next.  It is a Fox 45 on a Shameless.  Keeps quiting on out side maneuvers.  Maybe I have the tank to low on the plane looking at it from the front.  Just need some flying weather.

[Bryan Higgins]

Awsome

[Bill Little]

Hey Pat,  I printed off the little plan file for the P-47.  A lot of parts to be cut and if you get the price set for all of them I may have to mortgage the house to get them.  The wife already says I have too many planes.  I keep telling her I need the planes for the engines I have.  Found another LA 46 that needs a home.  The Fox I am playing with has issues.   Bigiron made me a venturi set up for it, but I think I have tank problems.  Have a rectangle clunk I am going try next.  It is a Fox 45 on a Shameless.  Keeps quiting on out side maneuvers.  Maybe I have the tank to low on the plane looking at it from the front.  Just need some flying weather.

Hi Doc,

I'm sure you know it, but Pat is very reasonable on his stuff and the wood he uses is perfect.  I usually only get ribs or ribs and formers, but he has made me a Twin Ringmaster kit in the past (two 20-25FPs, built up fuselage, etc.) and it was as good as you can expect from a quality and cost standpoint.  (and no I am not a paid employee! LOL!!)

I think we are really blessed to have the cottage makers involved right now that we have.  Pat, Walter, Tom N, Bob Hunt, Pat King, Mike (those are the ones I know and can think of) make the greatest products we have ever been able to get!  Even the best "production kits" from the past do not stack up.  Those guys, and John Brodak (not a "cottage" guy anymore! LOL!!), deserve a lot of credit for "bringing back" available C/L stuff for us.  AFAIK, Sig was the only major company that did ANYTHING for C/L.......

Great new designs, reproductions of the past kits in way better execution, laser cutting (no die crushing!), outstanding hand cutting, etc., etc..  We ARE in the good times!


BTW: I had a Fox .40 Stunt ('70 GMA type) on a profile and I had to raise the tank well over 1/4" to keep it from cutting off inverted or going outside.  Don't have a clue as to why, but it finally worked just great.

Big Bear

[Pat Johnston]

Doc,
I would be honored if you would like to be the prototype "beta" tester of the P-47.  I'll make you a special deal on the parts.  It will be sometime next week until I can get the parts sheet ready.  I'm looking forward to seeing this one get in the air.
Pat Johnston
F.O.D.  (Friend of Doc)
Skunk Works

[Bill Little]

Doc,
I would be honored if you would like to be the prototype "beta" tester of the P-47.  I'll make you a special deal on the parts.  It will be sometime next week until I can get the parts sheet ready.  I'm looking forward to seeing this one get in the air.
Pat Johnston
F.O.D.  (Friend of Doc)
Skunk Works

DO IT DOC!!!!!!!!!!!!  DO IT, DO IT, DO IT!!!!!!!  You HAVE a LA 46 looking for a home.......   You always do a very nice job on construction, and it will be a great flying model!

No way I can, doing a F-4F Wildcat "special" right now, myself, or I would JUMP at the chance. (and I can't even jump with my knee.....)  You will NOT be disappointed!

Big Bear

[John Sunderland]

  Hi Pat! I have been admiring you design work for several years now. A quick question here if you dont mind. I have some semi-scale aspirations that would really lend themselves well to your layouts. With your thrust line located as is, does this present any issues related vert CG or LO placement? I have noted you don't often use any dihedral. have you had any trim issues or funnies it hard turns, wings level in trim, etc.

 

[phil c]

"I did take a little departure from my usual airfoil by incorporating one similar to the High Performance Ringmaster series and +P Combat series.  This airfoil is a pure ellipse on the front 20%, transitioning back to the trailing edge with a straight line, tangent to the ellipse.  It has proven to be successful beyond all our expectations."

For even better performance use the front half of a NACA 0018.  Gary James has another version developed using Xoil(Mark Drela).  It is another 5-7% better in terms of absolute peak lift.  For a stunter you really should use Al Rabe's style airfoil.  Having a flap coming off of a flat-back airfoil puts a real kink in the section when any significant amount of control is used.  It can and will stall the flap.  Look at some of Igor's old posts.  With this kind of airfoil the L/D hits a peak around .8 or so, drops significantly, and then starts climbing again.  That kink in the L/D curve can make the plane do some weird things if it gets hit by a gust of wind.  The flap stalls, the plane bogs down, and starts to fall out of the sky.

[Pat Johnston]

John,
Practically all of my semi-scale based stunt planes use dihedral to get both wingtips in line with the vertical CG.  One of the few, interestingly enough is the Wildcat, which has the wing placed in just about the perfect location to not need dihedral.
As far as the airfoil goes, I am not intending on using all that much deflection of flaps, so the separation of the airfoil at the hingline is a reasonably non factor.  I believe that the front elliptical airfoil is very efficient as the ellipse has a perfect mathematical ability to move the air smoothly over its surface.  Don't have a wind tunnel, but it sure works well with what we have played with.  Of course, we are using smaller area flaps and relatively large TVC's which make the tail so effective, and the turn so forceful.
Pat Johnston
Skunk Works

[PJ Rowland]

"Don't have a wind tunnel, but it sure works well with what we have played with.  "

What do you mean you dont have a Wind tunnel I thought everyone had one..

Here's one I prepared earlier.. - This old thing ? 




 

[Pat Johnston]

I just worked up costs for the rib and former short kit.  The 1/8" former sheet will need to be spliced as I do not have over 4" stock, but this will make for a nicer former layout with one piece formers. All my wood is contest grade unless high strength is needed somewhere.  Here is the breakdown of costs:
$15~   Plans (two sheets)
$33~   1/16" ribs with 1/32" L/G doublers
$30~   1/8" formers
$10~   S&H (Priority Mail)
  $88~  Total
Hope that helps out.
Pat Johnston
Skunk Works

[t michael jennings]

Mr. Johnson,

The Fuselage Plan indicates;
      Wing Span:  55.25 in
      Wing Area:   579 sq in

The Wing Plan indicates:
      Wing Span:  60.00 in
      Wing Area:   684 sq in

Not sure which is the correct information.

Please clarify.

Thanks for a good looking P-47D.


T Michael Jennings     
Knoxville, TN.

[Bill Little]

Mr. Johnson,

The Fuselage Plan indicates;
      Wing Span:  55.25 in
      Wing Area:   579 sq in

The Wing Plan indicates:
      Wing Span:  60.00 in
      Wing Area:   684 sq in

Not sure which is the correct information.

Please clarify.

Thanks for a good looking P-47D.


T Michael Jennings     
Knoxville, TN.

Hi T. Micheal,

Not Pat, of course, but apparently Pat posted his ".60 size" plans (for the wing) before he made the corrections.

Wing Span:  55.25 in
      Wing Area:   579 sq in

That is correct for his ".46" size planes.  He just reduces, or enlarges, things and then makes the changes/corrections for wood sizes and such on the new "size".
 
Big Bear

[Pat Johnston]

Thanks, guys!  I was thinking last weekend that I had not transfered the new information to both sheets for the new 46 sized design.  At least you guys are paying attention.  Must have come awake with both eyes open!
Pat Johnston
Skunk Works

[Mark Scarborough]

Pat does that just to see who is paying attention, lol

[john e. holliday]

Doc,
I would be honored if you would like to be the prototype "beta" tester of the P-47.  I'll make you a special deal on the parts.  It will be sometime next week until I can get the parts sheet ready.  I'm looking forward to seeing this one get in the air.
Pat Johnston
F.O.D.  (Friend of Doc)
Skunk Works

Let me know. 

[t michael jennings]

Gentlemen,

Thanks for the clarification.

T Michael Jennings
Knoxville, TN.

[Steve Helmick]

Hi Wayne,

If you blow up the section right under the nose on the fuselage side view, it tells of laying up a fiberglass cowl.  Two layers of .6oz cloth and a cover layer of 2oz. cloth.   It can be built like the rest of the fuselage of course, I was just wanting some of the "secrets" of making that buck out of beaded foam which Pat describes.  Cutting and shaping beaded foam always makes me ill......

Bill

MAYBE Patrick meant cellular foam, but his phone was using that word at the moment? There certainly is no reason you couldn't use cellular phoam, since it goes away after the farberglass is dun. Gasoline will disolve the foam out of the cowl molding in short order. Cleaning up the presidue might not be so easy, so augering out all the foam you can prior to the chemical attack would be a good bet.  Steve

[Pat Johnston]

Thanks, Steve.  For a minute, I thought it was Celluose foam???  Whatever...  The foam mold for the cowl with the fiberglass is the only way to go.
Starting on the Razorback version is a couple of minutes.
Pat Johnston
Skunk Works

[Bill Little]

Thanks, Steve.  For a minute, I thought it was Celluose foam???  Whatever...  The foam mold for the cowl with the fiberglass is the only way to go.
Starting on the Razorback version is a couple of minutes.
Pat Johnston
Skunk Works

Hi Pat,

You know we ALWAYS pay attention to any announcement about a design you make.

I recently came across a couple hundred scalpel blades made by Persona.  They are similar to the X-acto carving blade you mention (#26, #27??).  Pretty thin and RAZOR sharp, of course.   I will start hacking away at the foam with one of those when I get to that point.  Might even go the "Scary Sharp" route if necessary! LOL!!

Bill

[John Sunderland]

John,
Practically all of my semi-scale based stunt planes use dihedral to get both wingtips in line with the vertical CG.  One of the few, interestingly enough is the Wildcat, which has the wing placed in just about the perfect location to not need dihedral.
As far as the airfoil goes, I am not intending on using all that much deflection of flaps, so the separation of the airfoil at the hingline is a reasonably non factor.  I believe that the front elliptical airfoil is very efficient as the ellipse has a perfect mathematical ability to move the air smoothly over its surface.  Don't have a wind tunnel, but it sure works well with what we have played with.  Of course, we are using smaller area flaps and relatively large TVC's which make the tail so effective, and the turn so forceful.
Pat Johnston
Skunk Works

Gotcha....like your thinking and designs as well. I noticed your TVC s are semi "french" and fancher looking   and 3/4 (smaller %) ish flaps but had no idea your stuff had dihedral...guess I have been looking at profile views but not very carefully. I have had this Laird Turner Meteor on the board off and on for a decade now. Considering getting serious and getting it built. Its a center line design and no dihedral but barrel fuse radial type stuff always gets my attention. My thinking is that although I like the semi-elip wing shape and understand its merits, I may nose around the Yatsenkos Sharks a little more before finalizing my drawing since it is a center line layout. Wish I had one to play with...and the money to purchase it.

Thanks Pat!

[Gerald Schamp]

Hi All,

I started the Brazilian size P-47 and got as far as making a molding buck for the fuse and a nice set of sheeted foam wings from Bob Hunt. Built a fuse but it was too heavy and now the buck and foam wings are just setting. Anyone interested, I would sell all for $125.00 including shipping, in the USA. You will have to sand the diehedral in the wing roots, but should be fairly simple. Thanks, Gerald Schamp. You can email me at geraldschamp@comcast.net. 

[Gerald Schamp]

The wings and molding buck are sold. Thanks much, Gerald Schamp 

[Pat Johnston]

Well, Doc, I have the cutting files done and you are in the "Q" for cutting parts.  Give me a little time as I have quite a few orders.  I'm trying to dig my way out of the pile, but it will take a month or two to get this one out.  Too much to do, not enough time.  Isn't that the way?
Pat Johnston
Skunk Works

[Pat Johnston]

I just got back to Gerald.  He lit a fire to do a profile version of the P-47D.  This should be a fun one.  I'll pull the wings in at the center to get the wing area back into the 560 range I customarily use.  Probably about 1 1/4" will do.  That should be easy.  The center two ribs will be a little closer together, so it may look just a little bit unusual, but what the heck.  At least all the existing ribs will still work and not have to be altered.  This will be fun for anyone wanting a profile competitor.  Hitting the 40 ounce mark should be doable with using the foam filled fuselage construction technique I've been doing lately.  Plans to post sometime this week.
Pat Johnston
Ever Designing
Skunk Works

[Pat Johnston]

The wing for the profile is done.  Total wing area is 566 squares.  54" span.  That will be perfect for a 46 or if a person wants the ultimate grunt, an ST51.  The fuse will start tomorrow.
Pat Johnston
Skunk Works

[Pat Johnston]

Here is the profile P-47.  Shown in both "C" and "D" models.  Pays your money, and takes your choice.  Notice the use of the 1/2" foam interior.  (Home Depot or Lowes).  This technique allows the use of very light 1/16" balsa skins for full support of the skins.  The result is an extremely light fuselage, and because of the overall 5/8" thickness, is rather stiff.  Once again, with an LA46 this one will be a killer.  For complete overkill, use an ST51.  Hope you enjoy the profile version.
Pat Johnston
Fast Track Design
Skunk Works

[Pat Johnston]

OK, as they say this is the last iteration,,, Fer sure, fer sure!  WW talked me into rounding the nose a little.  I made the changes on both the full bodied versions and the profile versions.  Here is a final shot of them all.  No changes for the wings.  As Mark Scarborough says about the wheel spacing "Wide track!".
Pat Johnston
Skunk Works

[Pat Johnston]

Doc Holliday!
I just cut you the official hard to get, prototype "beta-testing" Super Short kit.  This has plans, ribs and doublers, formers, fuse sides and doublers and a handful of 1/8" X 1/4" strips for the fuselage.  This should get you a ways along in the building process.  The most difficult part is to come up with the canopy.  Anyone?  Can you help out the Doc?
Pat Johnston
Laser Cutting
Skunk Works

[Bill Little]

Doc Holliday!
(snip) The most difficult part is to come up with the canopy.  Anyone?  Can you help out the Doc?
Pat Johnston
Laser Cutting
Skunk Works

Hi Pat,

I do believe the Sig 9" WWII canopy will be the best " *available* choice" as you have called out on the plans.

Big bear

[Pat Johnston]

Bill,
For the "D" model, the Sig 9" WWII canopy would be perfect.  Unfortunately, Doc's version is the "C" model which has a sharp front windshield.  That is a critter of a different color.  I suspect this will involve a plug to be whittled and a canopy formed over it.  That is beyond my pay grade for sure.  I bet we have someone here on Stunt Hanger who can help out.
Pat Johnston
Skunk Works

[Bill Little]

Bill,
For the "D" model, the Sig 9" WWII canopy would be perfect.  Unfortunately, Doc's version is the "C" model which has a sharp front windshield.  That is a critter of a different color.  I suspect this will involve a plug to be whittled and a canopy formed over it.  That is beyond my pay grade for sure.  I bet we have someone here on Stunt Hanger who can help out.
Pat Johnston
Skunk Works

Yep,  Nothing available, commercially, that I know of for the Razorback.  Sorry, I somehow missed that part.  I thought he was doing the bubble canopy version.

Big Bear

[john e. holliday]

Back when I played with F2C, we had to make our own canopies.  The ones we made were made of plexi-glas.   

[Bill Little]

Back when I played with F2C, we had to make our own canopies.  The ones we made were made of plexi-glas.   

HI Doc,

I am 100% positive you can make a very nice canopy to use on that wonderful new Razorback!  It ain't roc(OOOPPPPSSSSSSSSSS!!!!!!!!!!!!! LOL!!) hard to do.  As you know the problem comes with producing multiples in a short amount of time with a cost effective means, which is left up to the "commercial" guys. 

I still have a "F-86" ("Wicked Witch") canopy buck and plate to make one from that was carved in 1958.  it still works great.  Almost every old magazine article from the '50s and early '60s showed a small detail drawing of pulling a canopy.  I guess I have just become too lazy to spend the extra 30-45 minutes ot do it!

(now, I am waiting to see the first construction photos of the Razorback P-47 ".46 size".... what's taking so long??  LOL!!!!!!!!!!!!)

Big Bear

[john e. holliday]

The postal service.  Yeah I will blame them.

[Bill Little]

The postal service.  Yeah I will blame them.

Doc, you know how impatient I am......... I really love models of the P-47, especially the Razorback! (although, thanks to a great member here, I am building a REALLY LARGE P-47 bubble canopy model now! )

And I "still" have to make a buck for my P-51B canopy............ so I can't talk about being "slow"! (it's been "on the bench" *almost finished* for over 3 years.......... got some "go juice" for ME?) 

Big Bear

[Ron Merrill]

Pats,working on my full bodied 700+ sq. in. Corsair. Ron.

[Bill Little]

Pats,working on my full bodied 700+ sq. in. Corsair. Ron.

Hi Ron,

On my *list* is a ".ST G.51 size" F-4-F that he "resized" from his .60 size model.  I have the laser cut ribs ready and just have to finish stuff that has been on the table too long!

Pat does a great job for us.   (now, if I can just convince him to do a Cosmic Wind "Little Tony" in a .60 size for stunt (he did one for Scale), I *might* have all the planes lined up that I need to finish out my career!

Bill

[Pat Johnston]

Bill,
If you want a very scale-like Little Tony for stunt, the scale version is 650 inches, which is a great size and all a person needs to do is re-do the airfoil, maybe alter the tip width just a little, (not enough to show) upsize the tail a tiny bit and Shazam!!! (As our buddy B. Clinton would say) you have a very scale like stunter.  It wouldn't be all that difficult to do, but I will wait until the Wildcat gets going and the P-47 is in the air. 
Ron's big Corsair will be a hoot.
Pat Johnston
Still Designing
Skunk Works

[Ron Merrill]

Bill, my life gets shorter and my plane to do list gets longer, and Pat doesn't help with his outstanding offerings . Whats an old man to do? Ron.

[Bill Little]

Bill,
If you want a very scale-like Little Tony for stunt, the scale version is 650 inches, which is a great size and all a person needs to do is re-do the airfoil, maybe alter the tip width just a little, (not enough to show) upsize the tail a tiny bit and Shazam!!! (As our buddy B. Clinton would say) you have a very scale like stunter.  It wouldn't be all that difficult to do, but I will wait until the Wildcat gets going and the P-47 is in the air. 
Ron's big Corsair will be a hoot.
Pat Johnston
Still Designing
Skunk Works

Hi Pat,

Yep, a "Little Toni" is for much later!   

Things are speeding up around here, and more is getting done, finally! LOL!!  I do have a "plate full" for at least "this" year.  When the P-47 plans get here, it gets "SHOVED" to the front of the line!

Bill