From the Workshop — Building the Ultimate Thunderbolt

Sep 26, 2012 3 Comments by

This exclusive “From the workshop” story is from Frank Tiano’s article published in the 2012 December “Scale Special Issue” of Model Airplane News. Not exactly a Flight Report or Product Review, it is Frank’s take on building one of the very best warbird kits he thinks is available today, the CARF-Models P-47 Thunderbolt.

Let’s get to the story!

I like the fact that I’ve paid enough dues that occasionally someone acknowledges the experience I have acquired in building and flying model airplanes. So naturally when an editor from Model airplane News calls and says, “I hear you have a Composite-ARF P-47, would you be able to write an article about it for our readers?” Obviously, the answer to his question was “Yes”.

 
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Video by Keith Mackey

Composite-ARF, now CARF-Models has been manufacturing scale models for many years. So, I about had a heart attack when I heard that their next release was going to be a model of my all-time favorite, the Republic P-47 Thunderbolt, commonly called “The Jug”! I have been a Thunderbolt nut, since I don’t know when, and have probably built at least one from every kit or plan ever produced. Let me see, Don Smith, Nick Ziroli, Meisterscale, Top Flite, Bob Holman, Aerotech, Bud Nosen, ParkZone, Troy Built, and Hanger 9 readily come to mind and I’m sure there’s a few others I forgot! And as good as they all were in their own right, none of them totally compare with this one. No writer looks forward to doing reviews or articles on stuff that one might consider crap, or semi-crap. (Semi-crap is something that is half good or half bad. Like a great looking model that flies like a piece of—wait for it—Crap!) This model is the antithesis of all that! That’s right, this is not only the finest P-47 I have personally owned, it just may be the consummate ARF WW2 scale kit available in the modeling world today.

INGREDIENTS Okay, so I’ve spent maybe 250 words on what some may think was drivel, but you’re still with me right? This thing comes in a box large enough to double as a refrigerator, if you could get it to hold ice. The finished model’s wingspan is 110 inches so it’s got to get in the box somehow. In this case, two large wing panels and two freakin’ huge fuselage sections.

(Above) These are the fuselage components just after removing from the massive shipping box. The outline looks very accurate. All parts are molded extremely well.

Every part is flawless, whether it’s a piece of hardware or a major component. There is no instruction manual in the box; you have to get that by going online and downloading the four dozen or so pages. But that manual is good, containing several clear pictures on each page demonstrating the entire assembly process. There is very little building, that’s how they get away calling it an ARF, but trust me, it’s still a lot more than a hop, skip, and a jump from sitting on the workbench to sitting on the tarmac. But, however long it takes to assemble it, it is all enjoyable. Check out You Tube for some flying videos. Andreas Gietz, owner of CARF, flew the prototype at Top Gun two years ago and it was an instantaneous hit. I imagine he received over a couple a dozen unsolicited orders that day!

(Above) The Fowler style flaps are pre-hinged and removable. Fowler flaps move rearward before moving downward, which increases the wing area as they are deployed.

Getting back to my rant, the main composite parts are ready for hinging control surfaces, installing servos, mounting the engine etc. All the hardware for pushrods is included. Servos must be installed, most of them slip into place, but a couple of them require some patience. The flaps are real Fowler type and are one of the cool features not found on any other P-47 model available today. Aerotech had them on their 82-inch model, but I think that one is history. You have the option of sliding the canopy open manually or by using long-travel air cylinders. I chose the air cylinders and it is really cool. There are more rivets, panel lines, hatches and surface details than you would expect. Yup, like that pasta sauce, it’s already in there for you. Oh, here’s a nice touch; to keep the main wings protected from hanger rash, CARF has thoughtfully included padded wing bags. And while this T-Bolt was designed around the incredible, but sometimes pain-in-the-butt, 5-cylinder Moki 215 or 250 radial, it will accommodate any 120cc twin-cylinder engine. It’s comforting to know in advance that regardless how you build it the weight will be between 52 and 62 pounds, or approximately the weight of Andy Kane’s toolbox. And speaking of Andy, he is the fourth dude I spoke with who found that no ballast was required to make it balance on the indicated CG.

RECIPE No model comes with everything, other than some foamy parkflyers perhaps. So if you’ve seriously thinking about it getting one of these Jugs, keep in mind you’re gonna need a bunch of expensive stuff to get this bird off the workbench and into the air. Surprising though, the list is really quite short. Of course you need a radio. (Don’t you just hate those articles that tell you that you must have a transmitter and receiver?) But you will also need at least eight high-performance servos, like in the 200-ounce torque range, recommended for all the control surfaces. Of course, for other less demanding operations, standard servos with torque around 60 ounces are fine. I’m speaking about servos for throttle, choke, retract valves and anything else of that nature.

(Above) The landing gear is manufactured for CARF by Sierra. It is very high quality and has a scale “Shrink Strut” which shortens the length of the strut as it retracts into the wheel well.

CARF offers a custom landing gear system for the P-47 as well as scale 7-inch diameter wheels and tires. There’s even a 4-blade propeller option if you care to go all out! The cowling is large enough to accept many engines even though it was designed around the Moki 250 radial. I am told that there are at least two 4-cylinder engines that will fit. For assembly we used about a bottle of ZAP CA and one of ZAP-A-GAP medium CA as well as some 5-minute and 30-minute Zpoxy. By the way, when I say “We,” I am including master modeler Denny DeWeese, who did a large portion of the regular assembly and all of the tricky stuff for me, as well as for two other Thunderbolts we built in the FTE workshop.

(Above) I consider the P-47 as a piece of equipment, not just a big expensive ARF. Everything has to be installed correctly and there’s lots of work to do to get this Thunderbolt in the air.

(Above) This is a completed wing panel. This one belongs to Eduardo Esteves. We built three of these in the FTE shop! The Sierra wheels and tires are 7 inch diameter, available as an option.

It is important that all metal fixtures, nuts and bolts, linkages etc., receive a drop or two of “Blue” thread locker. We used Zap’s Z-42. When it comes time for painting, you have your own favorite products I’m sure. We use nothing but Klass Kote epoxy paints here, on all our scale models, and have been since it was introduced. You can’t really ask for a more durable finish, not only easy to apply, but completely resistant to most solvents.

 

When it comes to any complicated, markings found on scale model aircraft, most of us go to a company called Pro-Mark. They can make you accurate paint masks or markings in vinyl or in Dry Transfer type from your supplied artwork. All the small nomenclatures, like “No Step”, “250 Gallon Fuel Tank”, “Tail Jack Goes Here” and other call outs are available on one large sheet of dry transfers. Try them when you need something, by contacting them at ProMark.com.

GLITCHES & CHANGES Every model has a few things that are either difficult to deal with or maybe even a mistake. This one is no exception. However, there are only a few things, one of them being an opinion, another has already been corrected and the rest is just a pain. The elevator servo installation was very tedious, but that has been corrected. I am surprised that a model of 50 plus pounds uses one elevator servo instead of two, but in retrospect, the installation has worked just fine. The tailwheel retract unit was very difficult to install and still remains so. In all kits, the removable stabilizers and elevators use carbon fiber tubes that have been drilled and tapped to hold things together. If I had used the supplied tube for joining the elevators, which has a specific installation orientation, and is pre drilled and threaded, the elevators would not line up equally. I had no choice but to glue the stabilizers to the joiner rod, once they were aligned, joining the elevators forever. I didn’t like it but had no choice.

The cowling is fastened from the rear, behind the cowl flaps. It is very difficult to get the bolts to their respective holes. We ground the tip of every bolt to a point to help locate them and that helped, but it was still a pain.  I say “was” because eventually we changed over to moveable cowl flaps. The tailwheel doors use a mechanical method to drag them closed with the gear strut. I replaced all that stuff with two air cylinders. By doing it this way, I can access inside the tailwheel area by just pulling the doors open, without having to extend the gear itself. We also moved the radio tray further towards the front of the fuselage and that has proved to be a bonus.

ON THE POSITIVE SIDE One would hope that after spending as much on a model aircraft as you might for a brand new Fiat that there would be a whole lot of goodness, both in value perceived and in feelings, when the project is completed. There is. All through the assembly process, which by the way is probably somewhere around 200 hours, not including painting, I couldn’t help but marvel at the quality of each part and the fit of them, to each other. The hardware included is all first class. Unfortunately Metric, but at least it was quality Metric, not like that cheap stuff you find in some models. If there are any strange metals or materials in this baby, they are camouflaged well.

The surface detail throughout is nothing short of incredible and when checking against many different documentation sources it was nice to see that panel lines, hatches and various other details are in the correct locations. The “trick” things like the Fowler flaps, sliding canopy and the shrink strut, landing gear work perfectly. The two main wing panels join at the center, using two tubes for spars. The center joint is covered by the lower fuselage belly pan. The fuselage is cavernous; able to hold a PowerBox, multiple receivers, dual batteries and anything else you can think of. As I mentioned earlier, the tailwheel doors have a mechanical linkage to close them. The air cylinder option is not shown at all, but you can replace all that linkage with small BVM air cylinders and “Tee” them into the main gear air system. I found that one Ultra Precision UP3 air valve can handle it all, including the sliding canopy by teeing into the main gear air lines.

(Above) The cowl flap servo has its own channel but is mixed with the landing gear channel so that they are open for cooling when the gear is down and the fold closed when the gear is up. You can see an example of the linkage looking in from the rear.

My friend Octavio Losito in Brazil fabricated a set of servo activated cowl flaps for Eduardo Esteves and me. They are truly a work of art. I mixed it into the landing gear’s retract switch so when the gear is down, the canopy and cowl flaps are open. As the gear retracts, the canopy slides to the closed position and the cowl flaps close for cruise speed. My new Futaba 18MZ transmitter allows me to do all the mixing, piggy backing and unusual operations with ease.

FLIGHT OPERATIONS

This is the part you’ve been waiting for. The part where I describe starting the engine, throttling up and getting this bird in the air, right? Well, wait no more. Editor Gerry thoughtfully asked Photographer David to join me for the maiden flight. Hind sight being 20/20, he was hoping to catch a fabulous “Cover Shot”. We arrived at the flying field Friday, to beautifully clear, sunny and rather warm Florida weather. Within 15 minutes we had the Thunderbolt full of aviation gas and 170ci of compressed air. Five minutes later the Moki 250 was purring like a sewing machine, turning the BOLD 30×18 2-blade prop at a comfortable 4,500 rpm.

I taxied out to the main runway. I turned it into the wind, lined up on the centerline, slowly advanced the throttle and the big Moki smartly pulled the P-47 forward. I am estimating that with just a little back pressure on the stick, the Jug tracked pretty damn straight and left the ground causally after maybe 300 feet. I didn’t want to let it fly off prematurely; I wanted it to get up a good head of steam. With a runway weight of 59.9 pounds plus 50 oz. of fuel, I thought that might be best. It was. I’d say it took about a half lap of Paradise Field before it was up on step, cruising along smartly, so I reduced throttle to about half and then dialed it in. Once flying perfectly in the “hands off” mode, I made as many photo passes as David Hart needed to satisfy his photographic artistry desires. Once David was satisfied that he had enough for General Gerry, I landed.

The first landing, rather than being a little warm, was uneventful. The big airplane settles in at a very predictable rate but it did require careful monitoring of throttle and airspeed. At 60 pounds and with those huge flaps, there is an abundance of lift produced but a bunch of drag as well. So I needed to add a little throttle if the Jug appeared to start dropping vertically faster than it was proceeding forward. No biggie, subsequent landings were a piece of cake, each one smoother and smoother.

During the second flight I thought I’d try the most popular maneuvers we use at Fly-ins and competitions, like Top Gun. Rolling maneuvers were fairly quick and a bit sloppy, showing the need for aileron differential, which solved that problem. It tracked very well through any vertical line, like when going up for a Cuban-8 or when doing a loop. I see the reason for the amount of right thrust built into the design. So, in essence, the airplane is fully aerobatic and very “true”. Nothing else to say, anything more would simply be redundant. Oh yes, I almost forgot, it is also a freaking bullet! I had no idea that an airplane this size could be so fast if you allowed it to unwind! Conservatively, I’d say that coming down hill at maybe a 30 degree angle, from say 200 feet altitude, the thing gets past 120 mph pretty easily. Most of the time I flew it at half-throttle, or a bit more, and it looked great, sounded great and flew just perfectly.

IMHO I’m being very careful here to not let my love of the P-47 Thunderbolt to play a part in what I say. Magazine editors like General Gerry require the writer to give an overall opinion at the end of their article, so here’s mine. Over the past several years I have written about many model aircraft and fortunately for me, and the manufacturer, all of them have been very good. Surely they wouldn’t release a bad one on purpose! This is my first CARF model. I have heard that others are pretty good, with some areas that need to be addressed, but regardless of that, they all fly well. This one is different. This one really has no faults at all. Nothing, Zippo, Nada, Bupkis! The little time consuming areas of assembly are completely forgotten by the third turn in the pattern on the maiden flight.

All things considered do make this the consummate WW2 model to date. Make no mistake; this is a flying machine, a sophisticated piece of equipment that you treat like a Ferrari, in every way. Why? Because it is like a Ferrari, in every way—craftsmanship, power, performance, smoothness, predictability, sexiness, and price. You will treat it like a Ferrari as well. Just as I do. You know why? Because you will love this thing Man!

 

Specifications

Model:        P-47 Thunderbolt

Manufacturer: CARF-Models

Wingspan:  110 in.

Wing area:  2,280 sq. in.

Weight:       59.9 lbs.

Wing Loading: 60.64 oz./sq. ft.

Engine req’d: 120 -150cc 2-stroke, 250cc 4-stroke radial

Radio req’d: 6 to 7 Channel (throttle, rudder, aileron, flaps, elevator, retracts, choke optional)

Price: $3,790

Wing Numbers

Weighing about 60 pounds dry, and having almost 2,300 square inches of wing, this plane has a wing loading of 60.64 ounces per square foot. That is a relatively light wing loading if you keep in mind that on a model airplane, after about 80 inches of span, Wing Volume starts to play a significant role in how heavier airframes handle during slow flight. The thickness of the wing becomes an important factor in the wing loading. So, in a 60-inch model, a wing loading of 60 oz./sq. ft. would be unacceptable, but in a 110-inch-span model, 60 oz./sq. ft. is nothing to be concerned about.

 

(Above) The artwork for Blond Angel was duplicated for me by Pro-Mark. I mailed Jerry Caudle a plastic model decal sheet to blow it up to my size requirements. He offered the markings in printed vinyl or in a dry-transfer. I tried the vinyl and am very pleased.

(Above) The machine guns look really authentic, especially after we steel-wooled the finish and rounded the edges.

(Above) Being the nut jobs that he is, Eduardo asked Denny DeWeese, our master builder, to fabricate a working landing light, one that extends and lights up when the landing gear is down and retracts when the gear retracts. It works perfectly!

(Above) The Moki 5 cylinder radial packs 250ccs. It turns a 32×18 two blade prop at 4500 rpm or the 30×14 Solo 4-blade prop system at 4000 rpm. In either case, the engine produces so much thrust it is almost impossible for a small person to hold onto the airplane when running it up.

(Above) We had one of Eduardo’s friends make us up some custom exhaust, just for appearance. It adds a lot of realism but does not affect the sound or performance.

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3 Responses to “From the Workshop — Building the Ultimate Thunderbolt”

  1. John Nansen says:

    Folks, this truly is the ultimate, what many of us dream of having someday. My hat is off to MAN, Frank Tiano and all of the folks that worked on this plane and of course CARF-Models. Trully a museum piece. Cheers, and keep that beautiful jug flying!

  2. MR ABADIE Jean marc says:

    Hello franck
    CAN YOU M ‘EXPLAIN THE KINETIC OF THE COMPONENTS OF THE ENGINE HOOD
    i thank you
    tks

  3. MR ABADIE Jean marc says:

    hello franck,

    Can you explain to me the kinetics of the components of the engine hood of the p47 thank you in advance

    the best regard
    tks

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