Sukhoi SU31



  • This review was first published in January 2004, the kit is still available.

Once again I found myself looking for a replacement aerobat or fun-fly model… fortunately for me there’s not enough room here to divulge the circumstances as to why such a replacement was required. Let’s just say, the less said the better!

I’ve enjoyed kit building, balsa bashing or whatever you like to call it for many years now; the trouble is that the ‘traditional’ built-up kit is becoming more and more scarce.
A trip round my local emporium saw me playing a new game – ‘spot the balsa kit’ – of the 34 on display only two were what you’d call ‘true builder’s models’. So, faced with such a poor selection I soon became tempted by the latest treat from Black Horse. Yep! It’s an ARTF… if you can’t beat ‘em, join ‘em!


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The kit duly arrived courtesy of Slough Radio Control Models, and first impressions were very good. The individual assemblies were well protected within the box, bagged up, and separated by cardboard. Closer inspection revealed the wood quality (balsa, ply and liteply) to be very good. All the joints looked perfect as far as I could see, and a beautifully applied film finish (Oracover) finished it all off; there were one or two wrinkles in the covering (as is often the case with an ARTF) but a quick ‘going over’ with an iron soon had these smoothed out.

The canopy is pre-fitted and you’re treated to some cockpit instrumentation and pilot. A factory-painted fibreglass cowl and wheel spats are also included, which are very strong but lightweight. Control surfaces are pre-glued and pinned, with the pushrods pre-installed in the fuselage, and all the necessary hardware and accessories are included. All in all, a pretty complete box of bits. Oh, and I mustn’t forget the colour illustrated instructions – they’re a work of art and leave nothing to chance. The omens were good.


If you want to pick up a kit on Thursday and fly it on Saturday morning then get a Black Horse Su-31 – it won’t keep you waiting in terms of building!

Wing halves are married with a robust hardwood joiner, and I’m happy to report the panels lined up perfectly on a trial fit. Do note, however, that exit holes had to be cut for the draw strings that are used to pull the servo leads through each panel before joining.

The undercarriage is quite fetching in its red anodised finish; it’s a two-piece alloy item that’s much easier to straighten in the event of a hard landing. Wheels are the lightweight foam variety, held on with collets and wrapped with tidy fibreglass spats. Actually, the best thing of all is that said spats passed the ‘Smiffy’ test. Yes, I’m notoriously ham-fisted when it comes to these yet, so far, I’ve not managed to crack or break ‘em, which is quite an achievement for someone like me.


With the wing in place the belly pan fairing was trial fitted, whereupon it was noted that one of its formers clashed with the bolts that hold the wing in place. A little trimming of the offending former soon had things sorted. Incidentally, the belly pan has a quick release catch on one end and a locating dowel at the other.

That just left the tailplane and fin assemblies to glue in, remembering to remove the film around the contact areas to ensure good adhesion, and to check the alignment with a ruler.

I’ve gradually changed over to four-strokes over the years, my chosen power plant for the Sukhoi being the SC 52.
The instructions advise that you place a four-stroke with the cylinder head at 8 o’clock, though there is a cooling channel built into the underside of the fuselage where it’s recommended that the exhaust of your chosen power plant be located. The cowl is a good fit around the front of the fuselage, and not wanting to cut big cooling vents in this gorgeous item I mounted the SC inverted. I’ve had problems in the past with one or two ARTF’s when trying to get the engine under the cowl, mainly because of the carburettor coming up against the back of the mount. No trouble here, the nylon mount has plenty of length and there’s a lot of adjustment in the cowl, too. The cowl just about swallows the engine, in fact, modifying the exhaust slightly and fitting a remote glow would leave very little showing.


The tank completes this end of things – it’s a nice 8oz example with a bung that actually seals up before you strip the screw thread, this having been my experience in the past.
Our last chore between building and blue yonder is hooking up the control surfaces and this seemed to take longer than anything! Whilst they’re already in position, the pushrods require that you open up the exit holes at the rear of the tail to let them out, as it were. The elevator has a double pushrod, linked in the servo bay by a nylon block with socket grubscrews. I rather liked this, it made adjustment very easy to perform. The rudder is similar in that both run in a pre-fitted tube and are attached to the servo with grubscrew fittings. Some may not like these, but in truth, I’ve never experienced any problems with such items and always use threadlock on the nuts and screws. You’ll need to exercise careful placement of the throttle pushrod with an inverted engine as it will foul the tank if you’re not careful.

With the control throws as per the instructions and the model balanced in the middle of the C of G range, we were ready to roll.

On arrival at the club strip there were many admiring glances, with many compliments for the Far Eastern workforce who built this model. I just wish I could claim some of the credit! A range test was completed and with the SC running at full bore she was pointed into wind and let go. Not much time was wasted getting airborne – the Sukhoi simply leapt into the air!

It very soon became apparent that this was one bucking bronco; very sensitive elevator control pointed to a tail-heavy model – I had a fight on my hands if I was going to rein this one in! Three or four circuits later I was ready to quit while I was still marginally ahead, but the engine quit for me when the SC spat out its plug! Tip-stalling all the way down, she came in on what looked like a near-vertical landing, just missing the biggest oak on the patch… she was down, and I was left wishing I’d donned a pair of bicycle clips…
A quick adjustment using 6oz of lead up front and I was ready for launch No.2. This time she behaved herself, and with a few flights under my belt I began to regain some semblance of confidence and settled in to what is a rather nice model, with the SC 52 providing ample power. Inverted flight needs no trim adjustment, rolls and snap rolls are fast, and inside and outside loops are no problem. Slow her down into wind at a crawl then she’ll start to waddle and slowly drop a wing, but nothing your average club flyer can’t tackle.

In summary I would highly recommend this model, I love it. It’s of top quality, far better than I’d hoped for at this price. Once sorted she was a fine performer, but do watch that balance point!


Aircraft type: Semi-scale sport
Manufacturer: Black Horse Models
UK distributor: Ripmax
RRP: £129.99 (Nov 2010)
Wingspan: 55''
Wing area: 496 sq. in.
All-up weight: 6 lb
Wing loading: 28 oz / sq. ft.
Rec’d engine range: .40 – .53 two-stroke, .52 – .70 four-stroke
Rec’d no. channels: 4
Control functions: Aileron, elevator, rudder, throttle

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