Mike's P-47D Thunderbolt 48" - Page 5 - RC Groups
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Feb 08, 2009, 12:51 PM
Trampling out the vintage
Originally Posted by E-Challenged
These foam/balsa/ply hybrid building techniques make it possible to build light, great looking, great flying, relatively inexpensive, smooth surfaced, models that are not available in big boxes as ARF's. Thanks for the informative thread.
Exactly. Can't wait to see the approach they take for the wings and what the weight turns out to be.

The fundamental issue of balsa vs. foam is that balsa allows more shaping and a greater variety of finishing techniques, but is heavier than foam when comparing the strength of the materials. These hybrids may be able to get the best of both. It's exciting to hope that this model will attain the smooth surface of balsa without as much weight.
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Feb 08, 2009, 02:40 PM
Mike Brinker
tr6world's Avatar
Guys, early estimates were that this plane would come in around 2.5 pounds (Mark, correct me if I am wrong).

Greg, your right...... The idea that I could have a fun scale 48" wingspan warbird that would still be able to be hand tossed and flown in a park type setting was a huge attraction to me. As I looked through my options for kits and ARF's, all of the P-47's were either small 30" - 39" birds or 60" + planes that weigh in at 7 - 10 pounds. They required bigger motors, batteries and speed controllers. They also needed a larger area to fly.

As far as
balsa allows more shaping and a greater variety of finishing techniques
I'm not willing or able to debate this point because of my lack of experience with model building, but so far, I have been very pleased with the outcome.

I can say that so far, I have been really surprised how much shaping we have done with the pink foam. Take a look again at the razorback! I know that balsa can be curved and sanded, but the foam can be cut and sanded to a similar shape and be lighter.

Baldguy, I was amazed to see how light and strong Mark's planes are. Some of his recent projects are balsa are balsa fuselage, foam core wings with balsa sheeting and as you can attest, provide for a strong light build. My P-47 will also have a foam wing sheeted in balsa.

Coming up next will be the carving and sanding of the nose-ring, final preparation of the rear surface to receive the horizontal tail piece and cutting of the hatch section.

Feb 08, 2009, 02:54 PM
Gravity sucks.
mrittinger's Avatar
I think Mike will agree that this project is a lot of fun and a lot of learning curve
The foam fuse technique was tried on my first Jug in 98, a 42" MM reverse powered ship that came in under 42 ounces..with a 10 cell 1350scr NiCad pack!
I learned a few lessons on that one that are being applied here, like the keel to keep things straight and to distribute and shock or loads.
This bird ought to come in rather light, depending on the glass/primer/paint used.
The wing will be cut in "inner" and "outer " sections, joined, then sheeted and cut to the ellipse, also something I tried on the N model. We are still thinking about aileron setup, as I have grown really tired of seeing nice scale ships with servo's hanging out like a tired dogs tongue.
Basically, my idea is that there are many way to skin a cat, and many different materials to choose from, all of which can be used in different applications.
My opinion is that a great many models today are STILL overbuilt for thier applications. IE, my Spit has a built up wing with NO joiner in the center, yet it cartwheeled and did not break.This tells me all those ply and spruce joiners in .25 size birds are not really needed...just quality fit .
Feb 08, 2009, 03:15 PM
Retired and Lovin' it!
TPfingston's Avatar
Mark & Mike, the first time that I can recall this type of construction was in RC Modeler Magazine, Sept '84 issue. It was a DC-9 for two .049 pushers. I'm sure that it would still be a good plan for electric conversion for someone interested in modeling commercial aviation. It is a 44 1/2 inch wingspan. I thought then that it was a very neat way to build. Plans are located here if anyone is interested: http://www.rcmmagazine.com/store/sto...oSgdtE6GA0m8B0

I really like the Razorback P-47 and you guys are doing great with this one.

Feb 08, 2009, 04:43 PM
I eat glue
A lot are way over built. Look at Brian Taylor's 70" Hurricane, all balsa spars, with 1/16 shear webs, no spruce. I think my 46" Rittinger Hurricane will come in around 38 ounces ready to fly with an Eflite 15, and 3s lipo, shouldn't be any trouble handlaunching at that size and weight. I did use some foam on the build, front hatch carbed from foam, covered in 1/32 sheet, and the rear bottom fuse carved foam, then stringers.
Feb 08, 2009, 05:27 PM
Gravity sucks.
mrittinger's Avatar
Bg, you will have no issues with that at that weight. My first designs in this range were 45 ounces with nicads and brushed geared setups. What helps a lot is the big prop pushing air over the wing/stab from a standstill. Basically, it's half-flying when you throw it
Feb 08, 2009, 06:25 PM
I eat glue
I figure even if I hit 42ounces it won't be a problem with that wing area. What size prop you think I should be spinning on this beastie? Hope to paint this coming week.
Feb 08, 2009, 07:51 PM
Gravity sucks.
mrittinger's Avatar
I will have to look up an Eflite 15. Have any numbers on it?
Feb 08, 2009, 09:34 PM
Registered User
E-Challenged's Avatar
My GWS Zero had a tendency to develop cracks in the foam near the rear wing mount area due to hard landings. I would try to beef it up a little there.
Feb 08, 2009, 09:54 PM
Mike Brinker
tr6world's Avatar
Let me remind those who are lurking as well as those who have been participating in this thread that my building experience has been limited to a couple of kits and some ARF's. This project is nothing like what I have done in the past. I am not very creative or mechanically inclined. I would consider myself kind of a hack with little patience and not much for detail .

I say all this not to put myself down, but to encourage everyone who would love to build and fly something like this project but might be afraid to try. I know..... it is easy for me to say because Mark is pretty much leading me through all of this..... but if you ever want to try this, either connect with someone that has some experience, start with some kits or even try something like this project and learn from your mistakes.

I really am having fun and have learned a ton from Mark. Could I do this by myself the next time around? Based on what I have learned so far........ yes, but I am sure I would be asking a lot of questions and making a lot of mistakes along the way..... and the outcome would not be as nice as this. Time will tell.

Last edited by tr6world; Feb 11, 2009 at 09:22 PM. Reason: spelling
Feb 09, 2009, 12:06 AM
I eat glue
950kv, 575 watts max. 3s to 4s. 10/6 to 13/6.5 prop, leaning towards the 13", on 3s.
Feb 09, 2009, 12:38 AM
Suspended Account
have a look at this linkage.
it'll give you that nice, clean look.
Feb 09, 2009, 09:29 AM
Gravity sucks.
mrittinger's Avatar
Bg , these birds in my Warbird Series like to fly around 60 MPH top end and with the thicker wing slow to about 20 or so. I fly mine with an 800Kv and a 12-8 MASTER AIRSCREW on 3S. These props have a nice undercamber and pull really well compared to the APC of the same size. ANother option is the new Wicked props , which I have yet to see but appear to have a wider blade at the tip and a some undercamber.
12-8 seems to give good top end, good vertical pull, and a nice fat fan up front to push air over the wing and tail from a launch.

E;, The wing will be glued to the fuselage on this one, and we plan on using either 1/16 balsa or 1/64 ply on the inside of the fuselage as a doubler/radio mount. Any place that you have a sharp corner is asking for a crack...I learned that doing autobody on Corvettes. Every corner gets a crack!

Feb 09, 2009, 09:32 AM
Registered User
Mark which of your warbirds is the easiest to build? I am not much of a builder but like your designs.
Feb 09, 2009, 10:33 AM
I eat glue
Is that a Master Airscrew electric prop, or their regular gas prop?

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