The Bronco Saga.
I was practicing landing on my sim some long time ago when I came upon a Bronco (OV10) as one of the models on the Sim. It had some peculiar flight characteristic and so the plane stuck in my mind.
Then while surfing I found plans for an electric version on the internet. I down loaded the plans and off I went to PLAN SCAN to have them printed with dreams of having this little beauty flying in about 2 weeks (poor misguided fool). I built the airframe from the plans which took very much longer then I imagined. The construction is very light and each piece had to be individually cut and then assembled.
1mm and 1.5mm balsa is very easily broken. As I was constructing the airframe I was becoming increasingly aware that these were only the balsa plans, there was no indication of where and how motors, servos, radios etc were to be mounted. The control to the elevator presented me with the greatest challenge until I found a 2mm Sullivan control cable in the hobby centre. I used lots of this for ailerons, elevator and rudders. Hitec HS55 servos provided the power for the control surfaces. 400 Can brushed motors and a 50 Amp speedie drove the 9×4.5 props.
Many months after starting the project was ready to fly. I took it to the airfield, Ibis in those days, to test fly it. It taxied nicely along the runway and climbed smoothly into the air. THEN it went vertical, STALLED, turned over and plunged into the runway. All those hour and the airframe was a TOTAL LOSS!! BLOODY STUPID PLANE I didn’t really want one anyway! More time passes, maybe 12 months, I look in the box containing the left over electric bits of the ill fated Bronco and decide that I will build another one. The first airframe has long sense been sacrificed to the fire gods. The flight of the first model was so short that I learnt very little that could help me with the construction of the second one, but I do decide that I will use less of the Sullivan 2mm Gold ‘n Cable and more servos. The rebuild, which took as much time as the first has a total of 6 servos. One for each of the ailerons, Then back in again (many times) for repairs and complete rebuilds.
The first Bronco one on each of the rudders, one on the nose wheel and one in one of the narcels which controls the elevator via the only remaining 2mm cable in the plane. I have stuck with the brushed 400 motors driving the props via gear boxes. With the second Bronco finished it was once again time for a test flight. I was extremely nervous after what happened the first time, but this time on a very calm late afternoon my Bronco finally flew. A couple more visits to the airfield and a couple more flights and I was starting to feel that this might be a plane, but really it flew more like a kite. Being underpowered it wallowed from side to side, and was blown about by every puff of wind. I tried changing the props to 9×6 but this had little effect. Clever people, like Don Tester tells of measuring current and rpm voltage and all sorts of thing, but I guess and use what ever I can find that will fit my wallet. That’s why I’ve stuck with can 400 motors, when I know that I should use brushless motors.I did change the motors to 400 size Cobalt brushed motors, they were only $25.00 each and I could still use the same Speedie. The change in perrformance of the plane was dramatic. I was even able to do loops and rolls of sorts. I was so pleased with the performance
that I decided to enter the scale event at the recent electric rally. This event was held on Easter Sunday. On Good Friday I had a practice flight in the Free Flight period. The takeoff was smooth, the climb out was great, and the flight was flat and steady. The manoeuvres I tried looked good. Even the smoke system was impressive. Wait! This plane does not have a SMOKE SYSTEM. An out field landing broke the vertical fins and elevator from the plane and still the smoke was rising.
A true CRASH and BURN. One of the motors had thrown a winding and shorted out the motor. This melted the wiring to the motor which in turn melted to the negative wire for the speedie and servos.
Once again the Bronco goes home in bits with many promises that I will not waste any more time on this STUPID BLOODY PLANE Well I have wasted the time (and more money),I’ve replaced the motor, the servos speedie and battery all survived the fire and once again the Bronco is ready to test fly