POWER DISTRIBUTION FOR SERVOS ON THE B25

As I mentioned earlier there are seven servos in my B25. Not a lot by some large model standards, but still, I think, a little too much to simply plug straight into the reciever.

In flight under load we could be pushing 6 - 10 amps with all servos working hard.

A company called SM services, near Cranfield, offer a range of 'black boxes' to cater for these requirements.

A device called the 'Powersave' would seem like a sensible solution.

This is a small box with very thick circuit tracks and 12 pairs of universal sockets allowing for a nice way to get power to all the servos. A couple of hunky A123 cells will provide all the amps required OR a 10 amp BEC from UH in HK might also save weight .

This Powersave costs  £29.95

see: http://www.smservices.net/acatalog/Large_Model_Units.html  for datasheets and other stuff.

Got the wing tgether today & strapped it to my trusty workmate. I connected it to 2 X 5000ma 3S

Lipos in series( = 22V)  Props =13 X 8 APC

I ran entirely at full power till the Graupner discharge module tripped the throttles down. Run time was 5 minutes & 38 seconds. So with normal flying conditions I expect that will increase quite a bit.

i have, however, room two more batteries if required.

More testing with different props to follow

Sounds like the DPM is working fine with both ESCs harnessed together then Peter .

A simple power calculator Excel sheet I did a few years ago used a formula of battery capacity / WOT Amps + 30 % .....for approx flight duration, allowing for typical throttle settings during flight. The actual full formula I used was

(((Capacity / WOT in air) [ wot static current - 11% ] X 60 ) +30%) / 1000 = minutes of flight.