In Part One
of this review I went through the build process for the P-51 Mustang PTS, which leaves the little matter of how she flew... Global warming played its part and presented quite sunny conditions for the maiden flight, though the wind was a little blustery. After several flicks of the propeller to draw fuel to the carb, I applied the electric starter and the engine burbled into life (flick-starting a three-bladed prop seemed a little alien to me, with that close-following blade a little too close for comfort!) After the smallest tweak on the needle, the revs settled nicely. I was surprised at just how quiet this engine / prop combination was at close quarters, in fact propeller noise could clearly be distinguished over the sound of the motor. The pickup from idle to full throttle was a little laboured, suggesting that the idle needle needed adjusting, however in the spirit of the review it was left as per the manufacturers setting, i.e. within the confines of the tamper-proof arrangement.
Out to the strip we went, and with full revs applied she ripped along after an effortless taxi across the grass strip, showing no signs of uncontrollable yaw and certainly no hint of nosing over. Those big wheels really do work well. As the speed picked up through the take-off run the tail lifted and, still showing no signs of instability, she lifted gracefully into the air. Minimal trimming was required and several circuits were soon completed. One thing that stood out at this point was the lack of forward flying speed, and despite retuning the engine on later flights for a leaner, faster run, the same flight characteristic remained. Initially this was a little disconcerting as it appeared that she was underpowered, however I tried a loop from level flight and she went around with no problems, and the engine hardly changed note. Hard 'banking and yanking' back on the elevator did little to upset her, and there was no sign of a tip stall, no matter what I did. With nose held high into wind and the throttle back she wouldn't even stall!
The box was passed around during the course of that first day so everybody could have a feel of this conceptual aircraft. It was indeed slow enough for a trainer. It flew like a trainer, landed like a trainer and handled like a trainer.
The following weekend it was back to the field for some more flights, but this time in calmer air. Again she taxied out and took off with very little input from me. Forward flight was a little faster than on her maiden outing, and with no wind flowing over those NACA droops I was finally able to make her stall. A very unhurried and quite sedate affair, she just dropped her nose gracefully and picked up forward speed again, regaining control instantly. Loops were effortless, if a little big, with the limited elevator control. Rolls needed considerable elevator input through the inverted portion, which really came as no surprise as all the training aids were still in place. She was behaving just like a high-wing trainer! Landing was a dream, just bring her round on a standard approach and throttle back to idle at the threshold (with the flywheel attached the Evolution 40 has a remarkably slow running speed). Keep the wings level and apply a slack handful of up elevator when your instructor yells "now!" and you're sorted.
Right then, time to remove some bits. First to come off were the airbrakes, which are fitted to the undercarriage. Take-off had the same forward speed but flight was now a little faster. Still nothing startling, though. Roll performance was slightly improved, and she needed four beeps of down trim to compensate for the reduced drag below the C of G. Once again she settled in for a text book landing.
All flights up to this point had been made with extended flaps, and these were the next things to go. The flaps can be hard-fixed in two distinct positions: fully up or partially down, at about 30°. This is achieved by attaching the linkage to a fixed plastic lug on the wing that has two holes in it for the respective positions. When the pilot has advanced sufficiently through his training a servo can be fitted to make flap control proportional. With the flaps removed, the Mustang was committed to the air once more. After a slightly longer take off run she was airborne and needed a full 7 beeps of up trim to achieve straight and level flight. Forward speed was now significantly faster, loops a little tighter and rolls considerably easier to execute, but still there were no nasty surprises waiting to bite the unwary as one might expect with an abusively flown, low-wing warbird.
So the time had come to bite the bullet and remove the NACA-sectioned wing droops. These simply tape into position and in practice had been virtually unnoticeable in flight. With them went my security, and when take-off time came I was quite apprehensive. What a lot of fuss over nothing, though! The Mustang now performed with increased speed and agility, showing none of the docile traits of the early flights. Control responses were crisp and flying speed was much higher, opening up the flight envelope quite considerably. When abused, the long awaited tip stall familiar to the Mustang planform manifested itself in a predictable half-flick, but I could only really get her to do this in a tight 'bank and yank' turn, and she did recover quickly and easily. This tip stall was repeatable, and in the same direction every time; starboard wing giving way first whatever the attitude of the model. So there she was... unleashed!
I spent the rest of the day flying circuits, climbing out to height and diving in for mock strafing runs up the strip. The profile of the Mustang really is a pleasing sight despite the colour scheme, which can be a little tricky at distance and altitude.
Can a low-wing warbird be a useful trainer for the first-time pilot? On reflection I have to say yes, though the stability is a little reduced from that of a high-wing trainer. Hangar 9 have done a fantastic job in taming the Mustang, resulting in a model that flies more like 'My Little Pony' than a wild horse! Even with all the training aids removed she's tame enough to enjoy with only a modicum of ability.
Would I buy one? Yes. Would I recommend one for a beginner? I think so. It might have to be under the confines of a buddy box system though, as that orientation is quite tricky. Gosh, a warbird trainer! Who'd have thought it?