Mini Leader – Part Two

Mini Leader – Part Two

Now, onto the build. The Mini Leader's step-by-step instructions are of the multilingual, picture-only type (without any text) that leave a lot to be desired for the beginners amongst us, but are perfectly adequate for anyone with a bit of knowledge. You do have to be careful not to miss anything along the way, though, so take time to study the photographs as some of the build steps are quite subtle.

With the wings supplied pre-joined, the only thing to do here is mount the single aileron servo and glue the wick-type cyano' hinges to the ailerons. The hardware is all plastic but of reasonable quality and up to the job. Moving rearward the next step is to step mount the tail feathers by the normal method of cutting away a bit of film and attaching the fin and stabiliser. Following the instructions, the suggestion is that you use cyano’ for this but I really prefer a good 1-hour epoxy, which gives you plenty of time to instigate any adjustments to the alignment of the flying surfaces. In the event this choice proved a blessing, because it was only after the tail was attached that I discovered that the wing was out of square to the fuselage. In a bit of a panic, cordless Dremel in hand, I had to slot the single rear wing bolt hole by around 5mm to true it all up. This hole is pre-drilled, as is the hole to which it mates in the fuselage, so this isn't too good. The front of the wing is retained with a pre-fitted dowel, so slotting the hole in the wing was the only viable option here. In the aftermath of this frenzied Dremel attack I made up a new carbon plate to capture the rear bolt in its new position, making for easy future alignment. With this issue sorted it was out with the cyano' again to wick in the elevator and rudder hinges.

The control surface horns are simply glued in place with cyano’, having pushed their barbs through the holes that must first be made in the balsa surfaces. These did seem a little unfinished as no backing plate was supplied, so I made a couple of simple items from thick Mylar just to supplement the glue. Servo mounting is via standard bearers, and the pushrods are all steel with 'L' bend clips and pushrod connectors at each end. With the control surfaces complete, I turned my attention to the undercarriage, wheels and fibreglass spats. This assembly looked sturdy enough on the bench, but was eventually to prove the weakest link.

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She was beginning to take shape now, and I sat back admiring her good (if not petit) looks. The tail is held off the ground by a wire skid that's mounted simply but cleverly by two large-headed, self-tapping screws.

When mounting the motor I discovered that the 2808/14 mount was too big for the little bulkhead, and ended up making a new one from 1.5mm carbon plate. Feeling slightly nervous after this I checked that the cowl would fit over the motor, which fortunately it did. However, I did notice that if I fitted the supplied black spinner instead of a prop nut, there’d be no cooling airflow, meaning that I'd have to introduce some holes into the cowling elsewhere. I eventually chose to cut three louvre-type slots into the underside of the cowl as opposed to the single large hole shown in the book. I also chose to screw the cowl on instead of using the suggested sticky tape.

After soldering the three motor wires and checking the rotational direction of the thing, I mounted the speed controller behind the hatch on the underside of the fuselage, just aft of the motor bulkhead. Placing the Rx above the wing, I found the aileron servo was mounted too high. With little choice of where to place the gear in such a small model I decided to sink the aileron servo into the wing as far as possible, and after some careful measurement a generous clearance could be achieved – a whole 2mm! At this point I was becoming a little worried about where the battery might go in order to achieve the required centre of gravity (3.2" / 80mm from the leading edge). I tried various locations and found that an angled battery position just under the canopy was the optimum placement, which enabled the front underside hatch to be used for battery access, if not for retaining it.

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The self-tapping screw fitting of the hatch cover itself was completely impractical, so I substituted this with a spare HS55 servo horn that swings into place and does the job perfectly. I chose 2mm connectors for the battery which, rated at around 25A, are quite adequate for the set-up. When running the motor in the model for the first time on my chosen 10 x 5" APC 'E' prop it was immediately obvious that there was quite a surplus of power! I could have knocked the prop down to a 9 x 5" there and then, but decided to give it a try in the air first.

Finishing off the build was accomplished by fitting the canopy and adorning the orange and white film covering with the supplied decals. She really did look impressive now. Before setting off for the patch I took some readings with my all singing, all dancing 'E' meter and found her to be pulling just a shade under 20A at full throttle, maintaining 11.1V in the process. This equates to 222W, which is 30% more than recommended. A little too much, perhaps? Well, maybe, but you don't have to fly at full chat all the time, do you? All-up ready to fly, my Mini Leader checked in on the scales at 24oz (680g) compared with the specified 21 – 23oz (600 – 650g); not enough to worry about. So, with the throws set as per instructions and dual rates dialled into my ol' faithful JR PCM9X, we were ready to rock. For my flight verdict, be sure to keep an eye out for the third and final part of this review.

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