Ultrafly Sukhoi 27 – Part One

Insidious this electric flying, isn’t it? Plenty of us glider guiders and power flyers are getting sucked in – whether we want to or not. Let’s face it, there’s a lot of fun to be had from a wider variety of models so why not? I must admit, though, I prefer to think of it as an extension to my modelling activities. This is easy to grasp when considering the differences between a sedate thermal glider and a fast flying, rapid rolling, jet-type electric job. I digress.

Having collected dust under the editorial desk for a while, the kit eventually found its way to me. ‘Almost ready to fly’, it says on the box. Really? There are some good quality foam mouldings in there plus numerous bits and pieces, so it looked more like a kit than an ARTF in truth.

First off, the comprehensive instructions are more than adequate for an intermediate flyer, which isn’t always a given. Expanded polystyrene foam mouldings are used for the fuselage, cockpit hatch, wings and engine nacelles and the tail and rudder surfaces are Depron foam. There is a ply keel and under panel plus a glass rod that curves around into a slot to form a wing spar. There are also two packs of mouldings – some of which are superfluous – along with wire push rods.

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What else? Well, two sheets of cut-out and stick-on decor follow the box colour scheme. A comprehensive looking handbook is also included, and I also received a box containing a gearbox-type motor mount plus fittings for the motor and the recommended prop. Oh, and I also found a bottle of foam glue and a tinted canopy.

Also supplied in my box was the D13/32 brushless which promised more performance than the brushed Falcon 400 described on the box lid. The gear setup provided gives 2.38 reduction which turns the APC 7x5E prop at some 9000+ rpm.


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Ultrafly Sukhoi 27

I decided to read the instructions and do a dry run first. Accuracy was good but some minor damage was noted on one wing panel and some parts of the mouldings were slightly rounded as if the mould had not been fully filled. No matter, a little filler will take care of that. The wing panel was fettled with a strip from a carbon tube let into the leading edge before backing with Polycell lightweight filler.

The curved spar seemed like it might be a chore, and I noted that it passed through a hole in the keel so some sequence of assembly was needed. I traced the power harness and servo routes via the moulded-in channels and noted that holes would need to be cut through the body and cockpit sides; this was easily done with a hot 18 watt soldering iron.

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The all-moving tailplane assembly took a bit of sorting as the arrangement seems over complicated. The bearing mouldings were drilled and the black nylon elevator tube cut to fit freely between the two when cyanoed to the ply. A hacksaw blade was used to make a few slots, then a white horn from ‘pack A’ slid to position and the whole assembly cyanoed to suit. The bearings were slipped on and the ends of the piano wire were bent to accept the tailplane halves. The bearing mouldings were then cyanoed to the ply. Easy. I used the hot soldering iron to open up the slot in the fuselage moulding to clear the elevator tube and horn, and on trial, it went together nicely.

Gluing up the main mouldings was easy enough except that the sketch showing keel assembly (procedure 3) was wrong – check before you glue up. I glued in the glass rod to the centre section but, when offering up the wings, realised that it was not going to be easy to align them with the fuselage. Cocktail sticks were glued in front and back to align the panels and I used a simple jig (books off the shelf) to align them correctly overnight whilst they set.

The tailplane and rudder parts are a sandwich from two 3mm pieces of Depron so I made a token sanding to round off leading and trailing edges before gluing up. The rest of the construction follows the instructions, but the engine covers are supposed to fasten using double-sided tape. I cut the front part off at an angle and glued to the fuselage so that the belly mouldings are trapped at the front; I just taped up the rear so they remove easier.

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Incidentally, the canopy / hatch has plastic mouldings and a magnet to align and fix – neat, that. Clear plastic mouldings are supplied to protect the belly mouldings; if your grass is forgiving, you might choose to use a couple of strips of heavy duty tape instead.

Filler was used where needed and the self-adhesive décor applied, while the leading edges of the flying surfaces were protected using Diamond tape. The radio gear used was a Jeti 5 receiver, three 9g Tower Pro servos and a HiModel 25 amp speed controller. A 3s 1500 LiPo was recommended; I sourced an Evo 20.

It was now time to check the balance point. This proved to be way back so again the soldering iron was plugged in and the battery housing hollowed out forwards by around 25mm. The housing was lined on the sides with a couple of strips of 1mm ply. The remaining adjustment took just 12g of lead in the nose to bring it to the ‘expert’ setting. It feels like it might go back a bit more.

That pretty much covers the build, so I’ll return shortly with Part Two of this review to let you know how the model handled in the air.

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