Model Forum / Radio Controlled / Air Models / August 2004

Hi

This idea is not new.  I can remember reading about something similar
here in the UK about 10 years ago - possibly a lot more (RCM&E
perhaps).  Whether it was merely theoretical at that time or had
actually been done I can't remember, but this plane sounds identical
as far as the idea is concerned.

From memory I seem to recall that the wire acting as the "servo" was a
specific length "tuned" to the radio frequency.  One end was fixed and
the other connected to the control surface. Transmitting a signal
heated up the wire, which expanded and moved the control surface.

I seem to think that it didn't actually need a receiver - just wire of
the correct tuned length; presumably for 4 function all you would need
is 4 different length pieces of wire, no batteries, no Rx, nothing!!!!

Perhaps somebody else can drag out the article or can remember more
details - we moved house a few years ago and had a ruthless clear out,
including my older RC magazines.

Regards
KGB

I don't know all the technical details, as I only use radio control in my
models. But from what I have read, there is a Infrared receiver on the plane
(like in a TV) and some kind of powerful Infrared transmitter attached to
the normal two stick radio transmitter, using the trainer cable.

The IR receiver then controls the motor and magnetic actuators with
"regular" electronics (much smaller than normal ofcourse, as the currents
are much smaller).
The magnetic actuators is, simply put, a double wound coil with a small
permanent magnet suspended inside. When a current flows in the coil, the
magnet turns based on the power and polarity of the current. A rod is then
attached to the magnet, and this is then attached to the rudder. The power
of a magnetic actuator is _much_ less than the power of a regular servo, but
enough to move the rudders of these ultraligth models.

/Lars

M-M <nospam@ny.more> scribed in <nospam
-D9E2C4.17592907082004@newnews.netaxs.com>:

go and read the flipping thing mate.  it SAYS it uses muscle wire for
control.  muscle wire is an alloy that changes it's size dramatically
when heated.  repeatably.  you can heat it by putting enough current
through it.   that is what they are doing.  2 Hz control rate.  good
thing the plane is stable (-:

swarf, steam and wind

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