Just Easier than solarfilming the cat!

‘A strange looking bird’ was my first thought on seeing David Payne’s SB-28 for the first time whilst doing my nightly trawl through all things ‘electric flight’ on the web. Having just completed a new camera plane from plans. I had been searching for more information about the designer, just to see what else he’d put into the air and had consequently stumbled upon the build thread on the prototype SB-28. With its unusual looks and under-wing graphics, it caught my attention and so I read on…

Nine days later the postman hammered on the front door demanding signature with menaces and there it was before me, the United States Postal Service standard triangular package containing a very neatly packaged block of balsa and ply, laser cut sheets which were to become my SB-28.

Instructions duly read. I opened up the pack of wood. The kit really is an excellent example of the laser cutters art, so full marks to Jim Wagoner at JTECH laser who helped turn David’s prototype into a kit for BlueskyRC that both of them can be proud of. I love the smell of laser burnt balsa in the morning, and in the end I just managed to refrain from ‘phoning in a sicky’. However, I was rather on the prompt side getting home you might say.

The instructions state half way down page one that ‘Though this is not a complex plane to build, it does require an experienced pilot to fly it – this is not a beginner’s plane’. This statement is completely true, but it is not that it is in any way difficult to fly, just small and fast, so you are never going to be flying in a straight line for very long unless it’s vertically upwards- which I’ve since discovered it will happily do until it disappears out of sight! Not too shabby then- for a park flier on a £13 motor.

I’m not going to go on about the build other than to say make sure you read the instructions properly. The cutting and design of the parts makes it a very quick and straightforward process; you might like to take a look at the build thread or online instructions if you wish for more detail on how it goes together (see link below)

Having now finished building the wee beastie I now think that the instructions for laser cut kits of this quality could be written more as below:

  • 1.Carefully remove the outer cardboard packaging.
  • 2.Make a small hole in the corner of the inner plastic bag and remove instructions and plan.
  • 3.Drip in this small hole 16 drips of thin cyano, 5 drips of thick cyano and two small blobs of 5-minute epoxy.
  • 4.Shake the bag briskly for 30 seconds then remove the built model from the bag.
  • 5.Gently sand and then cover in the lightweight covering material of your choice….

    Talking of which, owing to the shape of the inner wing area and area around the prop canyon, the task of covering looked quite daunting. My first thought was that it was probably going to be easier to solarfilm the cat than the little SB! Once I applied myself to the task it wasn’t nearly as bad as imagined and it all went on at the first attempt, wrinkle free.

    With the center of gravity as per plans, easily achieved by sliding the battery round a bit, control throws set and the right amount of exponential added, I took a drive down to the club field

    The shape caught their attention first and the group of usual suspects sauntered over to pass an eye over this strange newcomer to the field. Once the comments of “you do realize that you’ve glued the tail on the wrong end” and other helpful phrases had subsided a bit, I proceeded with the job in hand and herded them back to the ‘vultures gallery’ just behind the pilots box and waited for the heckling to start. Normally about three seconds after take-off is the general rule, earlier if it looks like you might crash it for their viewing pleasure.

    Having already run the motor up at home I knew the very different noise would give them something to start with so I deliberately chose to place the model on the end of the runway rather than taxi out.

    Deep breath, full power, the SB pops off the grass after twenty feet or so and accelerates rapidly so I rotate to 70 degrees and climb out to about 300 feet, nose over to level throttle back to 45% and put in a few clicks of trim on the elevator to sort it out.

    After a minute or two to explore the general handling I started to play around a little. The stability is absolutely as neutral as you could wish for both laterally and in pitch. It also tracks beautifully. The rate of roll is eye watering at any kind of speed (hence the large amount of expo) I also tried a square loop; the corners were the sharpest I have ever managed. It will fly at high angles of attack and very low speed much like a delta but still exhibiting the superb handling of higher speeds. An all round charmer if ever there was one.

    My timer chimed the news that it was nearly time to land, and only then did I realize that the gathered throng behind me have been absolutely silent…a real first in my clubs long history.

    As well as being a delight to fly, the SB has a presence well beyond the size of the model and a unique noise and shape to keep people looking, making it ideal for a display model, which is my intention for its use during the coming season. I’m currently working up a routine.

    I have to add that I have no connection whatsoever to anyone mentioned other than being a more than satisfied customer. I am just so pleased and impressed by this little model I had to tell someone!

    p.s. No cats were harmed in the making of this model.

    Whilst I’m here, here’s some info for the technically inclined amongst us:

  • Weight – 14.5 oz ready to fly
  • Motor – 130W 4700kV brushless inrunner
  • Battery – 3-cell 1300mAh Li-Po
  • Prop – 4.2” x 2” APC
  • Servos HS-55
  • RRP – $49 plus postage

    References

    The kit is available from www.blueskyrc.com click here to go straight to the website.

    JTECH laser. http://www.jtechlaser.com/

    The photos are by Gordon Walker, Tina Wagoner and David Payne