Gentlemen,

I've been active in Electric Control Line Speed for some time, using AVEOX equipment now about 12 years old.  Have managed to run some reasonably fast contest speeds, and am now building some new airplanes.  The weak link in my Class B airplane is the AVEOX  F5MV commutation module (they werem't calld ESCs then).  Dave Palumbo modified it with a few jumpers so I could turn it on (2 second ramp up to 100% power) and off with an an external timer which I designed using capacitor bleed down to trigger a miniature SPDT relay to give me a 36 second motor run.  Run time is critical, since any less would not complete my flight and much more would shorten battery life or (as has happened) blow the module.  My timer is powered (charge the capacitor prior to start by pressing a button) via a regulator from the propulsion battery- 18 cells.  Any more cells and the commutation module would evaporate. (it is rated for 60 Amp continuous and 120A surge- I run about 80A at start, dropping to about 72 at cutoff)


I'd like to take advantage of now AMA legal new cell technology to boost motor power, but this
means buying and setting up a high current ESC, and timer.  I had a good discussion with a customer engineer at Castle Creations and now am beginning to understand the questions I need answered.  The Phoenix 80 looks like the ESC- the problem is controlling it with the proper timer.  I am not an RC type, so did not realize the nature of the speed control signal to the ESC- no simple relay but a signal generator is required to program motor start, speed and run time.  Here is the performance schedule I'm looking for:

1.  An arming switch
2.  A start switch or button to apply power to the motor as follows:
    Two Second ramp up to 100% power
    36-38 second run at 100%
    Power cutoff.

I don't need speed governing, brake etc. however, if operation at less than 100% conserves battery charge, this might be worth working with later during the compulsory pre timing laps on the pylon.

Now my questions:

Since 30 seconds is too short and 60 seconds stresses the battery unnecessarily, am I limited to a JPM timer?
How is voltage applied to the timer?  18+ cells is too much for BEC.  Do I have to use some watch batteries or other separate power source?   Past experience with a 555 timer indicates that the running motor introduces enough EMI so that power thru a regulator chip might confuse the timer.

Any information gratefully appreciated.

Will Stewart