Twin edf Airbus A320 - Sad day

Details

Sad day for the A320

Sunday 9th January 2005
Following a complete radio failure, the plane went out of control and crashed in the trees nearby our flying field. It's really sad, this plane was a great flier. The right wing is damaged beyond repair.The airframe shows a few cracks but would be repairable. Consiering the violence of the crash, I can say that it is a robust design.
The plane would need major repair to fly again. After one year of work I lack motivation to fix it or rebuild a new one...

A 320 crashed A 320 crashed. Right wing is destroyed.

What probably happened

 A few seconds after the take off, the plane made a first tip stall. I recovered easily and  thought of some radio glitch. I took the wrong decision and decided to continue flying.
But a few seconds later the plane did not react at all to the radio and continued to fly on its own, flying perfeclty straight and smooth but becoming smaller and smaller in the sky. After 30 seconds of free flight, the radio decided to work again, and I was able to manage a large turn and bring the model back above the flying field. When I started the descent for the approach, again the radio stopped functioning. This time the plane was banking in the turn and there was no possible recovery. She crashed in the hill facing our flying field. 

Final word

To save weight, I didn't use a separate receiver battery. the radio was fed using the BEC on one of the two ESC. The voltage regulator of the BEC was probably unable to cope with current draw from the 4 servos, especially during take-off or landing approach. That's why the radio was cut at those critical moments.

 I also noted later, that on a twin engine model, it is much safer to have one battery for each motor. I've noticed The Castle Creations ESC don't like to be plugged in parallel

 My recommendations for a model like this are:

One separate battery for the radio. 40 grams for a 1000 MAH NIMH battery pack wont change anything to the performance of your plane

Keep the two motors independent. It means one ESC per motor and one battery pack per motor. It's better to install two 2 amps packs than  one single 4 amps pack and connect everything to that single pack.

 Despite the crash, the project was very succesful. This A320 model is a great flier, and i can only encourage you to build yours.