Ultrafly P51 Mustang Maiden/Review

Well, after having her sit in the stable for almost 12 months, and after a fair few nights finishing off little details the P51 Mustang had her maiden today at Kambah. It was a bright sunny day, with the only real concern being almost the complete absence of any wind - why would that worry me - we will come back to it.

The Plane

The Ultrafly Mustang is a parkflying P51 replica which includes micro retracts, flaps and a 160w FRIO brushless motor. Mrs Oz bought this one for me almost 12 months ago now, so I have taken my time getting round to getting her together.

The Build

Build Strengths:

• Good quality foam with positive lock together feel.
• Straightforward motor mounting for included motor.
• Instructions are straight foward and clear (provided you read the errata as well).
  

Build Weak Points:

• Heavy - as you put the plane together you just can just feel the weight building up.
• Hardware for flaps not correct (there are no pushrods that work).
• Threaded rods don't fit inside included control sleeves for rudder/elevator (I ended up using thin wire which fit).
• Decals not very sticky.
• Build takes a long time.
  

Calling this an ARF is stretching the definition beyond breaking point. I wouldn't know exactly how many hours I've put into it, and although I've done it in fits and starts I doubt it is that much less than my Stevens Aero RV4.

The Flight Pack

With a 6 servo set up the thing that is probably most unusual about this plane is that you must have a standalone Battery eliminator if you want to run flaps and gear (which I did).

So I used one of these Phoenix Hobbywing 25A with separate switching BEC. Receiver was an MKS 8 channel. Servos were a mixture of cheapies and hitech HS55.

Given the modest power requirements (160W) the battery was a 12C 2200mAh Elegance LiPo. I gave serious thought to using a lighter battery given the manual tells you to stay below an all up weight of 650g.

The Flight

As I said, the wind was very light - too light really (because warbirds land better with a nice head wind). Took off into the breeze. With no steerable tail wheel you are at the mercy of the gods as to where the plane turns as it accelerates. Of course the undercarriage is a delicate affair, and the method for locking in the direction of the main wheels leaves a little to be desired.

After takeoff I spent a few minutes trimming the plane. Once trimmed she flew very steadily, although, at an AUW of 660g she felt a little heavy in the air at all times.

Large loops even with full power were out, and even with aileron deflection set 50% higher than recommended (that was my high rates setup) the planes roll performance was not outstanding.

However, when she was riding along at mid throttle in the air, with her wings level, she looked the part, particularly as she passed overhead showing you her tucked in wheels underneath.

When it came time to land I was in a bit of a bind. The wind was coming from the South, but my time at the North end of the field had convinced me it was quite glitchy up there. I didn't want to temp fate with an approach from the North. The wind was almost non existent, so I decided to come from the South. However, this did mean a hottish landing would be compounded with just a little tail wind. Nevertheless, on approach it all seemed doable.

The plane began losing altitude alarmingly quickly as I reduced throttle, and I found she need to fly quite quickly to avoid a stall. I brought her in to land, flaring her nicely to touch her down - she still had quite a lot of velocity, but she made nice 3 point contact (showing she had no lift left to speak off). Then she rolled out for 5 metres, and hit a tuft of grass growing through the asphalt strip, no higher than 1/4 an inch above the surface. Not even enough to make the plane nose over, but enough to make the hopeless hopeless Ultrafly retracts collapse.

I can only say my experiences seem to line up with others with this plane. The power is a little disappointing, and the retracts are a joke.

Here is the youtube vid of my flight including the landing, so you can judge for yourself whether you thought I was too hot, made a mess of it, whatever.




I'm going to be trying a pair of GWS ultralight retracts on this plane. The seem to lock properly, which seemed to be a critical weakness in the other model. I'll let you know how it goes.

Summary

Without the retracts this model is a kind of expensive, hard to steer warbird, but it does fly pretty well (not withstanding power caveats). With the retracts/flaps it would be a nice to fly warbird with a great scale touch for the park..., if you didn't need to pull off not just a good landing, but a perfect landing every single time.