I have covered the build of the Ultrafly Sukhoi in Part One of this review. It was now time to check the throws, charge the LiPos and head to the field.
At a ‘midge’ under 23 ounces, the model has a ‘heavy’ feel about it but don’t let this kid you – there is quite a bit of wing area there. The ply keel has a grip included that makes hand launching easy; the waft from that brushless set up takes care of the acceleration to flying speed – and how.
After the first outing I paid more attention to setting up the differential, and in doing so the handling became more predictable. Oddly enough, I later found the stick-type motor mount cracked, so this was repaired with a binding of kevlar thread and cyano. I would probably opt to do this when building in the future.
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If you are accustomed to ‘Shocky’ type aerobatics on the end of your transmitter aerial, forget that. Expect fast concentric rolls and wide high loops more like an i.c. job – in fact, I have heard quieter power models. However, throttle back and the low speed handling is a real surprise. Like most flying wings and deltas, the stall speed is low and with a whiff of throttle and lots of ‘up’, it is possible to fly at an alarming nose up attitude – but with a rapid acceleration by opening the tap. Quite impressive. I made a mental note that with the short moment arm, it might be an interesting exercise to set the ailerons up as elevons to complement the elevator.
With dead stick, the glide is fast and flat but the handling is predictable. Pulling back on the elevator on finals will lift the nose, slowing the glide down so that it can be dropped in a quite a low speed. I like that.
As for what I dislike about this model? Well, not a lot really. The curved spar could be changed to a couple of ‘straight across the fuselage’ items that would be adequate and much easier to build. I stuck on the colour scheme panels but they looked a bit cheap, and some started to lift on the corners. I’m not a big fan of raw foam either, as it is liable to show handling marks quite quickly. It wouldn’t be too much trouble to use lightweight tissue under water-soluble varnish or perhaps even varnish straight onto the foam before applying the colour scheme. Elsewhere, the nose is the first thing likely to make contact with the ground sooner or later, and a piece of ¼” dowel glued in the nose would help keep its shape longer.
As I mentioned in Part One, describing this Sukhoi as ARTF might raise issues with the Trade Descriptions Act. However, the build is not too unpleasant a task so we might make some concessions there. Anyway, those are personal comments. The model is a treat to fly – a real contrast to the usual run of small electrics. Experience a low, fast fly past and you’ll see exactly what I mean…
