Now the P-47C Razorback!

[Pat Johnston]

The P-47C Razorback design did not take all that long to make up after doing the bubble canopy "D" model.  Just needed to modify the back half of the fuselage.  Possibly the biggest drawback of the "C" model is coming up with a decent canopy for it.  Of course, we have a stack of clever builders out there who form canopies all the time.  This might not be much of a hurdle.
Doc, give this set of PDF's a gander and see which version you like best so you can tell me which version you would like, D model or C.   We'll take care of you.  This is my part of the rest of the modeling community telling you how much we treasure your friendship and support.
The Razorback will have a great presence and the side area of the fuselage is a bonus for us stunt people.  Someone asked if a Magnum 53 or ST51 would be good with this one.  It would be spectacular and could be a world beater.  All of the grunt a person would ever want and with little weight penalty.
Pat Johnston
Design Studio
Skunk Works

[Jim Oliver]

Pat,
I almost talked myself out of the D model, and now you come up with this!  I know I want one, just don't know where I'll put it

BTW, I hope the plans give very clear instructions as to how to achieve the target weight.   I've never been able to do it......

Cheers,
Jim

[john e. holliday]

I like it.  It was something satching the old war films of the P-47's taking off.  I always wondered how they kept from scraping the belly of the plane.  Did I say I like the razor back/turtle deck!

[Pat Johnston]

Doc,
I'll get right on setting up the cutting files for the Razor back.  I'll be gone for a couple of days so I'll see you next week.
Pat Johnston
Skunk Works

[Bill Little]

Pat,
I almost talked myself out of the D model, and now you come up with this!  I know I want one, just don't know where I'll put it

BTW, I hope the plans give very clear instructions as to how to achieve the target weight.   I've never been able to do it......

Cheers,
Jim

Hi Jim,

It becomes a "life style choice".  Every thought during all construction must take on a recognition of whether or not that part is light enough.      

Ah.. Grasshoppa.............

Big Bear

[Jim Oliver]

Bill,
I've heard it said that, in the crash of a perfectly designed airplane, every part breaks.  I ain't there, yet!

[proparc]

I personally have always liked the bubble canopy version of the jug. I also preferred the P-51D version of the Mustang to the razorback version.

If I am not mistaken, moving from the razorback version, to the bubble canopy version on both full scale planes did actually cause yaw problems, which had to be corrected by increasing rear fin area.

[Wynn Robins]

Geez Doc - you're a lucky man !!!  Another stunning design from Pat.  AWESOME !!!

[Bill Little]

I personally have always liked the bubble canopy version of the jug. I also preferred the P-51D version of the Mustang to the razorback version.
(snip)

Hi Milton,

Well, we have reached an impasse.........    I love dearly love the Bubble Canopy P-51D (my favorite all time airplane!), but prefer the "Razorback" P-47........ hmmm.............

Of course, I did redraw Bob's P-51D Mustang to a P-51B, but for a little better "Scale" look to my eye, with out changing much else.  I haven't had a "D" model of the Mustang since my Veco kit back around 1965, but I have NO IDEA why!  (I do have laser cut ribs for a Classic Legal Rabe Mustang, guess I will have to build it before long!)
 
Big Bear

[Douglas Ames]

<snip>
If I am not mistaken, moving from the razorback version, to the bubble canopy version on both full scale planes did actually cause yaw problems, which had to be corrected by increasing rear fin area.

Dang'it, there's a word for the transitional fin ahead of the verticle fin on these two "bubble canopy versions", along with the B 737 and others. When I'm at work tomorrow I'll look thru the B737-800 AMM for the correct nomenclature. Knew it once...can't remember. Anyone?

Good looking model!

Sun. 2/6 - "Dorsal Fin" is what Boeing calls it, but I think Northrop called it smething else.

[Bill Little]

Bill,
I've heard it said that, in the crash of a perfectly designed airplane, every part breaks.  I ain't there, yet!

Hi Jim,

I guess that "theoretically", nothing but a could of dust would be left.  I ain't "there" yet, but I have been known to "try".

I remember Billy saying that : "I guess a stunt plane could be built too light, but I haven't one it yet."

Big Bear

[Pat Johnston]

That whole issue of building light is mostly about buying really good and light balsa.  All of the funny little schemes about hollowing the ribs of the stabilizer, etc, are just us fooling ourselves.  If you have balsa that is about 5# stock, then the strength is adequate and the weight is minimal.  On planes above 600 inches I cut 3/32" ribs from sub 6# balsa.  I also do not make the cutouts in the ribs all that big as you can see on the wing sheet as there is very little weight to save there.  When the ribs are out of the cut sheets, the weigh very little overall.  I have a tendency to not use wood over 6# in my own planes.  As an example, my latest is my Mako Shark which is 600 inches, uses full ribs and half ribs with external spars.  The ribs are 1/8".  Overall weight is looking like it will be about 40 ounces, maybe a little more with an LA46.  Not bad for 600 squares.  It is all in the balsa selection.
Pat Johnston
Skunk Works

[Bill Little]

That whole issue of building light is mostly about buying really good and light balsa.  All of the funny little schemes about hollowing the ribs of the stabilizer, etc, are just us fooling ourselves.  If you have balsa that is about 5# stock, then the strength is adequate and the weight is minimal.  On planes above 600 inches I cut 3/32" ribs from sub 6# balsa.  I also do not make the cutouts in the ribs all that big as you can see on the wing sheet as there is very little weight to save there.  When the ribs are out of the cut sheets, the weigh very little overall.  I have a tendency to not use wood over 6# in my own planes.  As an example, my latest is my Mako Shark which is 600 inches, uses full ribs and half ribs with external spars.  The ribs are 1/8".  Overall weight is looking like it will be about 40 ounces, maybe a little more with an LA46.  Not bad for 600 squares.  It is all in the balsa selection.
Pat Johnston
Skunk Works

Totally agree, Pat!

I had some three lb sheets once........ and some 4 lb that was wind checked!  The wind checked 4 lb. was almost useless since it was cracked all over.

I do not do as some do and throw away a piece that is 3 grams over the weight I wanted... at least not usually, it depends on how BIG the part is that is 3 grans overweight! LOL!!

Bill

[john e. holliday]

Myself I have only once really tried to pick the wood for a plane.  Mostly tho I take wood for ribs and if it seems heavy I will take out a big chunk of the wood.   Also I have had some 1/16 sheet that was the pits even tho it was light.  With these hands of mine I kept poking holes thru the sheeting.  In Combat and Racing I never really worried about the wood except to make sure it would take the load imposed on the airframe.   On the racing planes it seemed the wood took less dope or epoxy to finish.  But I am one of the old dogs that tries to learn something everyday. 

[Bill Little]

Myself I have only once really tried to pick the wood for a plane.  Mostly tho I take wood for ribs and if it seems heavy I will take out a big chunk of the wood.   Also I have had some 1/16 sheet that was the pits even tho it was light.  With these hands of mine I kept poking holes thru the sheeting.  In Combat and Racing I never really worried about the wood except to make sure it would take the load imposed on the airframe.   On the racing planes it seemed the wood took less dope or epoxy to finish.  But I am one of the old dogs that tries to learn something everyday. 

Hi Doc,

A digital scale is always on the bench.  Used to be the beam/balance scales.  And every piece of new wood gets weighed and marked for "lbs" when bought.

Big Bear

[john e. holliday]

I have both.  A digital postal scale and a triple beam medical scale.   

[Bill Little]

I have both.  A digital postal scale and a triple beam medical scale.   

Just weight each piece when you get it, and check the "Density" with the calculator Sparky linked to.


Bill