100%E

In August last year I took the family on a holiday to Florida and while out there arranged to buy a MaxCim Brushless Motor from Tom Cimato. I had already decided to build a special lightweight version of my own design called 100%, with retracts and flaps, and was hoping for a target weight of around 7.5 pounds. Running with 18 cells the MaxCim draws 60amps on the ground and produces 1200 Watts running through a 3:1 gearbox driving a 13 x 8 prop. The first version of the 100% flew really well with an MDS58 until I stuck it into the ground at high speed following an attempt at prophanging too low to the ground! Initial motor runs with the MaxCim were fearsome! Getting me into some trouble at a friend’s house for blowing a load of soot out of his chimney onto the carpet!

Building progressed slowly but was promising in that the individual weight of the major parts such as fuselage and wings was about half the original ic powered version.I had intended to place the battery pack in a removable box under the wing, but unfortunately discovered this places the CofG too far rearward. For the first test flight I balanced it using lead (unforgivable on an electric I know!), but am now modifying the battery position so that I can loose the extra 1/2lb of lead it required to balance. After much delay due largely to the nervousness of the pilot, I test flew the finished aircraft on Saturday 15^th January at Peakirk. The model accelerated away rapidly and tracked nice and straight, easily lifting off and climbing away. The CofG was obviously still too far back but apart from that she handled well. Using the flaps produced a marked nose up attitude partly due to the rearward CofG I’m sure, so after about 3 minutes I decided to land ensuring I had plenty of power left to go around a few times if necessary. Landing without the flaps was quite fast but not excessive, so I was quite surprised that the retracts pulled out of the wing on landing. On examination afterwards in order to try and save weight I had used some hardwood bearers that were quite light beechwood and the screws securing the retracts simply pulled out splitting the wood. I am replacing them with proper hardwood, which should solve the problem, but I think for a while I’ll try taking off with the undercarriage down and landing wheels up until I get the flaps working well enough to slow it right down.

All in all it has been an exciting project to try with one of the most nerve wracking first flights I have ever tried! And I am looking forward to completing the trimming out process so that I can see what she is capable of. Hopefully I will get to fly it at Potters Way shortly and may take it to Old Warden in the spring for one of the own design days.