Modeltech P-51D



There are numerous warbirds that capture our imagination, and the Mustang is right up there with frontrunners like the Spitfire and Hurricane. The P-51D was the most common version of the Mustang in service; with a powerful Rolls Royce Merlin engine it shone in the Pacific theatre and became a familiar sight and sound between here and Berlin.
Whilst some kit manufacturers leave a lot to be desired with their products, Model Tech have become synonymous with good quality ARTF models over the last few years and their kits are a joy to put together. Wilson Li, the boss at YT International (UK distributor), will not accept poor quality and if a problem arises he’s on to it immediately with calls to the factory.

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This new Mustang is an addition to the expanding Model Tech range, a mid-size 58” wingspan model of ‘club-type’ proportions that doesn’t need special servos or a big engine to make it work properly. It has a scale outline, but with useful aerodynamics to ensure it handles well and is stable at low speed.

Although it’s an ARTF kit there’s still plenty of (easy) work to be done before we can take it out to the field and fly it. A brilliant, 64-page instruction manual containing 112 clear, black and white photos and 11 crisp line drawings ease the builder through the construction phase. It’s written in proper English, too, not an amusing translation as is sometimes seen. The manual splits the build into sections and details the components, tools and glues required for any given area. When a particular task has been completed there’s a tick box that can be checked to serve as a reminder of where you are in the build. The end of the manual features some pointers on general safety and tips on flying the model.
There’s nothing really to write home about in terms of constructing the Mustang, a) ‘cos it’s an ARTF and b) because everything went together smoothly. Anyway, I will give an overview of how it all goes together before we get to the flight performance… but of course, you’ve read that already, eh?

Building begins with the wings, which are made from ‘proper’ balsa wood as opposed to the material used by some ARTF manufacturers, which would be best suited for making lolly sticks!

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The wing panels are of built-up construction and completely sheeted, top and bottom, to provide a lot of strength and resistance to minor dings and dents. They are also nicely pre-covered in a familiar iron-on material.

Work begins by joining the panels with the dihedral brace and some 30- minute epoxy. The wing is then test-mounted to the fuselage for alignment and adjustment before other wing-related bits and pieces are glued in place – mounting plate, forward locating dowel etc. Thereafter suitable holes are drilled for the wing bolts and, if you follow the instructions to the letter it will all line up perfectly. With the wing still bolted to the fuselage, the radiator scoop is fitted. Said scoop is made from moulded plastic, which has to be lined with balsa before fitting. Some covering material must then be removed from beneath the wing to provide a good glue joint before the scoop can be permanently fixed in place.
There’s an option of fitting either fixed or retracting undercarriage. For the fixed option loose u/c mounting blocks are supplied which must first be glued in. Preformed undercarriage legs to suit are also supplied, as are a set of leg covers for improved scale appearance.

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For the retract version a set of silky mechanical items are supplied, with chromed and coiled u/c legs that are thoughtfully handed so that the shock absorbing coils go the right way in both wings. Wells to accept the retracted wheels have already been cut in the wing and need only the addition of a plastic liner to finish. Keeping it simple, the ailerons are driven from a single servo via pushrods connected to torque rods.

The fuselage is built from balsa / ply and is nicely made with good, snug fits to the glued joints. There’s even a coat of fuel proofer around the engine area. Tail surfaces are next on the list, requiring removal of the covering material from the mating surfaces where the glue joints will made.
Since the tail feathers need to be square with the rest of the model, it’s worth spending time here performing a dry fit before adding any glue. After all, straight models fly better than bent ones.

When the glue’s set the flying surfaces can be installed. These are hung with fabric-type hinges, which are designed to be soaked in thin cyano. Simple and highly effective.
The tail wheel is a steerable unit and bolts to the underside of the fuselage, connected directly to the rudder. No problems here, and it all seems to work well.

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Engine installation should be carried out at this point, however I hadn’t decided which engine to fit, so, whilst pondering the dilemma I installed the servos and connected up the control runs… except for the throttle, of course!
So, which engine to use? With the servos in place and the wings attached, some balast was hung on the front end so that the model balanced on its C of G. This was duly removed and weighed, after which it was simply a matter of finding an engine of the same mass. The Mustang can take a whole range of motors from .40-size two-strokes to .60-size four-strokes. In the event a supercharged Yamada YS 63 four-stroke was used. This is a very lightweight engine, and I had planned to run it in the Mustang prior to using it in a new Capiche 50. Trouble is, the engine is so ideal in the Mustang, it’s going to stay there, and I’ll have to get another YS for the Capiche… such is life. Installing the engine wasn’t a problem; the hardwood bearers simply needed to be trimmed away just a small amount to accommodate the slim crankcase.

First job here is to trim the fibreglass cowling to suit your chosen engine, then cut and fit the canopy. A pilot was glued in and the canopy adorned with some trim tape on the inside to highlight the framework before securing it to the fuselage using eight self-tapping screws.

Wing fairings are usually glued to the fuselage, but they are glued to the wings on this one. The fairings are again made from a plastic moulding and a bit of covering has to be removed from the wings before they can be glued into place. There’s a huge, polished aluminium spinner in the kit and it looks great, proudly pointing the way forward.

One’s final, and most rewarding, task of the build is accomplished with the addition of some decoration in the form of decals supplied with the kit. The controls and C of G were set up as per the instruction book and all that was needed thereafter was a sunny day to take it out to play.
Okay, this is the part that actually gets read… and then instantly disbelieved by a small band of miserable, ‘professional’ moaners who seem to frequent model flying forums and think that kit reviews are all fixed and ‘manufacturer friendly’. To put the record straight, boys and girls, RCM&E reviews are not fixed. If I find something good to say, I’ll say it. Conversely, if I find something bad, I’ll report that too… so there!

It’s off to the field we go. The Mustang instantly drew admiring glances while the new, supercharged YS 63 was being bedded in and set up. What a gorgeous engine it is, too.

First casualty! While moving the model around in the house earlier, I managed to knock off the aerial mast… twice. And while it was on the flying field, I managed to knock it off again, before even starting the engine. It was obviously telling me that it didn’t want to be on the model, so it’s been left off.

Having deemed the engine to be strong and reliable, and with all the range checking etc. out of the way, it was time to point the Mustang into the freshening breeze and open the throttle. Slowly at first, to get the feel of it and to check for any swing, then, with her behaving well and tracking nicely, the throttle was fully opened.

As the model accelerated, the tail lifted and she was away… wheels up, looking good and climbing for the clouds. In fact, climbing rather too well, in fact, several beeps of down trim were needed to level her off, plus a couple on the rudder and ailerons to get her going in a straight line. At long last, playtime had arrived!

The stall was first to be checked out, to see if there were any nasty surprises. There weren’t; this is a nicely sorted design that has no vices. Obviously the model will stall, but it gives so much warning before it does, and even then the result is fairly gentle and easy to recover. A couple of minutes of familiarisation followed, during which time the Mustang was put through rolls, loops, spins and flicks before handing the tranny to my lad, Daniel. He liked it so much that I had to threaten to cut off his mobile phone allowance before he handed it back!

With the controls set as per the instructions the model responds well without being too severe and the controls are nicely harmonised with each other. The roll rate is good but not too fast, and rolls are axial – a relief, bearing in mind there’s only one servo in the wing (no fancy differential mixing). All the controls were given 30% exponential to soften the initial stick response, and this has made for a silky smooth model that can be flown with confidence at low level without it leaping about at the slightest stick input. This is certainly an easy model to fly and you don’t need to be a hot- shot fighter pilot to get it under control. I’ve now flown the Mustang in some stiff breezes and she takes it all in her stride.

She looked marvellous at low level with the sun glinting off the silver covering, beating up the strip and presenting herself to the camera while the YS 63 purred happily.
With a roll of film shot, I sent the model to the heavens and really began to explore what she could do. This is definitely not a prop-hanging, 3D-type; she’s a scale model and knows it. That said she has excellent manners and can pour out the fun just like any good sports design. She’ll respond obediently to the merest command and, with the power available from the YS, enormous loops can be flown. Better still, try rolling lazily from horizon to horizon – fabulous! The rudder authority is a bit tame when flying more serious aerobatics, so with increased movement (i.e. doubled!) it’s now more ‘in the zone’. Stall turns are crisp and graceful and she’ll spin quickly whether the right way up or inverted. Spin recovery is virtually instant with no heart-stopping extra turns before she pulls out. Flick rolls are good… fast and clean, stopping when the sticks are centred. In fact, the flicks are so good the pilot’s head fell off during one of them… oops!
With the increased rudder movement the model could now fly knife-edge, making long, four-point rolls a doddle. Flying inverted presented no problems and just required a bit of down elevator to hold her level. This is a very stable aeroplane that handles well, whichever way up you want to fly it.

Whilst the Mustang is capable of flying aerobatics, she really looks best chasing after Me109s or flying around at low altitude, where she shows off her lines and markings (and that great big silver spinner) to maximum effect.
Landings are fairly straightforward. As you might expect, the big radiator scoop underneath the wing creates a bit of drag, so when throttling back it’s best to keep to a couple of notches above idle. She comes in very slowly, so there’s no need to be too timid with the throttle. Drop the wheels, line her up and drive her in, throttling right back just before touch-down. And if you get it right, she’ll settle onto her main wheels and roll a few yards before the tail comes down. Lovely.

Having flown the Mustang for several hours, it’s proved to be an extremely well mannered sweetie which looks terrific on sunny days and is great fun to fly. It’s now fully sorted out and can fly from horizon to horizon hands off. No problems have materialised with the construction quality, and the retracting u/c has stood up well to grass field use. Several people have flown the model, they’ve all liked it and been pleasantly surprised at how easy it is to fly. A common phrase heard amongst those who’ve flown the Mustang… “What a fabulous aeroplane.” Enough said!

Name: P-51D Mustang
Model type: Sport-scale
Manufacturer: Model Tech
UK Distributor: YT International, 01922 684425,
RRP: £159.95 (July 2011)
Wingspan: 58''
Fuselage length: 51''
All-up weight: 6.5 lb
Wing loading: 24.5oz / sq. ft. (dry), 26 oz / sq. ft. fully fuelled
Rec. no. channels: 4 / 5
Control functions: Aileron, elevator, rudder, throttle, retracts
Rec’d engines: .40 – .50 cu. in. two-stroke, .60 cu. in. four-stroke
Motor used: Yamada YS 63 four-stroke
Radio used: Futaba FF9 with PCM Rx, 4 x 3001 servos, 1 x retract servo, 1200mAh NiMH battery

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