Postby Dave Hayfield » July 21st, 2014, 12:49 pm
Some of you at the Cosford show may have seen my unfortunate CriCri 'landing'. It may have looked like an accidental crash but it was far from that, in full size flying terms it was a controlled flight into terrain or 'CFIT'. The take off was fine but after a couple of circuits I realised that the engines were not responding as they should and the elivator and aileron control functions were very much reduced. A close flypast at what was supposed to be slow we noticed one engine was at high revs and the other ticking over. I decided to end the flight so on the next approach I operated the 'kill switch' to cut both engines....no result...and the steerable nose leg was at a peculiar angle. This meant that one receiver was not operating, the one with the kill switch and the throttle for the high revving engine and the steering. I couldn't risk trying to land at flying speed because with no steering I had no idea where it would go and if I lifted the front end to try to steer with rudder it was at a speed where it would just take off again....I tried it...twice! We have all had throttles stick open and had to fly around until the fuel ran out but this model has a 2 litre tank which it shares with both engines, with the one engine at about 3/4 throttle this would mean cruising around for about an hour, not at a show I think. The alternative was to bring it down on the grass heavily to bring it to a stop. It worked safely and this is what matters. Not too much damage and on inspection the fault was a battery connection that came adrift, the model dismantles to several parts for transport and these are the parts that came apart. Lessons to learn? yes.. make sure that you can stop both engines whichever receiver fails and that steering is controlled by both receivers.
Thanet Model Flying Club
LMA 520
