The finish and build quality are top-notch, this Sukhoi looks simply gorgeous
I’ve been eyeing this model every time I’ve been to my parents house over the last few months and since my brother bought it at the Cosford show in July. On my last visit he handed me the box and said it was mine on the proviso that if I took it, firstly I paid for it and secondly I had to review it for modelflying.co.uk. A reasonable price was agreed which included the motor, ESC and the servos of which the latter didn’t get used, but more on that later. The model is aimed solidly at intermediate to advanced pilots as it will definitely be a little too lively for a beginner to say the least.
CONSTRUCTION
The construction quality of this model is a true work of art and certainly beyond my patience level. I think you’d be hard pushed to build something this intricate on the shed bench at home. Everything is expertly crafted and assembled using laser-cut ply and balsa. The first thing that struck me was how light the whole structure is, despite its lack of weight, it seems to be very strong though. The build quality is excellent as with previous SebArt offerings and the way that everything lines up without any adjustment is a fine example of the time and effort that’s gone both into the design and construction of the model.
The assembly of the model is a very short lived affair with very little to do once the box is opened. The hinges on the moving surfaces need to be lined up and although ready installed, need to be cyano’d in to place. What I do on this front is to remove hinges from the surface to be hinged and push a pin through the mylar (hairy) hinge in the centre so that each side gets an equal amount of hinge in place, the pin’s also help keep the gap between the surfaces equal. I then re-assemble the surfaces and once happy with the way they line up, I drop some thin cyano onto the hinge whilst in position and work the surface back and forth so the cyano whicks right into the joint. I do this on both sides of the hinge to make sure they are firmly stuck into position and once the cyano has set I remove the pin and do the same for the other surface.
The assembly is so obvious the manual is almost superflous. I normally do all of the surface assembly first before fitting servo’s and leave radio fitment as the last job.
RADIO GEAR
Although digital 2kg servos (JR DS385) are recommended, I chose to fit 2kg analogue servos (JR ES375). I was on a tight budget to get the Sukhoi in the air and the 375’s are the same spec as the 385’s, just analogue rather than digital. They are 9g sub-micro servos with an amazing power to their diminutive size and have a good turn of speed as well.
There’s plenty of room for a receiver and flight batteryWith regards to the motor choice this had already been made for me as there was one in the box that my brother had already bought for the model – a HiModel MAX BL2820-07 which is a 500w motor. Matched to this was a HiModel 40amp ESC and a 13×6.5 APC-e prop with power from a Hyperion Lite-Storm 2500mAh 3s Li-Po battery. I reckoned this would provide ample power for such a light weight model.
A nice little touch I thought was in the form of two vacuum formed air scoops which are designed to be glued either side of the motor box on the front of the model to guide cooling air directly on to the motor. This keeps the motor within a reasonable temperature range, something that will be handy during the summer months as its surprising how quickly motor temperature can creep up when you’re pulling 40amps or more. One thing I will note here is that any 40amp+ model I fly always has a PCM receiver as I’ve found in the past and in these higher powered applications, a PPM receiver just does not give me enough confidence, so to that end I fitted a JR R77S unit which is both lightweight and reliable.
FLYING
With the model flight ready and sitting on the bench in all her glory, the weather decided to take a turn for the worst and I had a nail biting four-week wait to give the Sukhoi a maiden flight. Although conditions were not brilliant and the wind was only gusting at 15mph, I decided enough was enough and that I really needed to get the model airbourne. It was very apparent just how lightweight this model was because I had to leave a battery in the airframe just to stop the model blowing away in the pit area! Against my better judgement a slot became available and as I had two cameramen itching to shoot something, I was urged to get the Sukhoi in the air. I lined the model up on the runway gently opened the throttle and with in a few feet she was climbing out a phenomenal rate. It was pretty apparent at this point that she was a little tail heavy but not so much as to be unmanageable. To be honest it was too gusty to make any judgement as to her flying capabilities so I decided to get her down and save the evaluation flight for a less windy day.
In the air she’ll only be restricted by piloting abilites and the flight set-up
A few weeks later the wind had died down to nothing and another trip was planned to the field. I added another 20g of weight to the nose to counteract the aft C of G. All I can say is it was well worth the wait as this model flies as well as it looks. The ground handling is excellent and with a take-off speed of not much more than a walking pace, the model was skyward with enough urgency to put a smile on the face. There is plenty of power with my set-up so the Sukhoi can be pulled vertical about 30-yards out without the slightest hint of stalling. The roll rate is superb even on reduced rates and the elevator and rudder are very powerful. The knife-edge is excellent requiring little or no coupling which may be due to the lift generators fitted to the undercarriage legs. The model flies more like a much larger model and is very forgiving so even my hamfisted attempts at 3D flying did not upset its composure. There is little to the stall and the model literally stops before anything happens, even then it just nods its nose and starts to lose height with a slight rock to the wings.
This model is a great confidence builder and an absolute joy to fly. I cannot recommend it any higher and it’ll be a favourite for a long time to come.
A little power is required to bring her in otherwise she may drop the last few feet
Datafile
