Open Spoilers Alarm on tow

Microswitch on release mechanism, microswitch on brakes. Pressure switch (
very low! ) in ASI circuit

Bistable arming circuit with 15 minute timeout.

Arm circuit with leading edge of tow activation. ( Open release to install
hook, circuit goes active )
While armed if brakes are opened buzzer goes off.
Circuit is disarmed when 40kts reached.

Ian

Jim,
So you are suggesting to measure the force on the tow tope, assuming
it would rise dramatically if the spoiler is open?
Sounds like a good idea, but:
1) Will it trigger in a ground launch? Won't opening the spoilers
REDUCE the load?
2) Would it trigger when the handle is just unlocked, and the spoilers
aren't actually out (yet)?
Uri

illspam (Jim Vincent) wrote in message ...
What about the towhook? Magnetic sensor? where? How? Other ideas

Install a strain gauge internal to the fuselage right up against the hook
mount. Get Peter Masak to design a simple circuit that trips an electronic
relay when the strain exceeds a certain amount. Knowing Peter, it should take
him less than an hour.

Jim Vincent
CFIG
N483SZ
illspam

I'd go for 'spoiler open' alarm sounding when open IF my hand is not
on the actuator. On tow or off tow, if they are open and I did not
open them I'd want to know. I've had both situations happen. My fault
both times.

Might make wiring a bit simpler.

Bob

illspam (Jim Vincent) wrote in message ...
What about the towhook? Magnetic sensor? where? How? Other ideas

Install a strain gauge internal to the fuselage right up against the hook
mount. Get Peter Masak to design a simple circuit that trips an electronic
relay when the strain exceeds a certain amount. Knowing Peter, it should take
him less than an hour.

Jim Vincent
CFIG
N483SZ
illspam

I'd go for 'spoiler open' alarm sounding when open IF my hand is not
on the actuator

I'd rather have my hand near the tow release instead, especially during the
first part of the tow.

Jim Vincent
CFIG
N483SZ
illspam

Uri,

The strain gauge would just indicate that the tow rope is under any load,
regardless of the amount, but triggered above some reliable value, perhaps 5
lbs. This would indicate that the tow hook is being used.

Jim Vincent
CFIG
N483SZ
illspam

Somewhere in this thread someone said "the microswitch on the airbrake
handle is the no-brainer part".

Detecting the handle position gives no protection for deployment of a
disconnected airbrake.

Cambridge 302, and I think L/S Navs, include a takeoff airbrake open
warning based on airspeed. It works well, but would need 2 in-wing
sensors to detect an open disconnected airbrake.



Andy

Jim Vincent wrote:

I'd rather have my hand near the tow release instead, especially during the
first part of the tow.

Most of the gliders I've flown have the tow release way
too far from my hand. Granted, I have short
arms (not a boxer), but do others commonly notice they
need to lean forward a little or twist shoulders to
pull the release on many gliders?
--

------------+
Mark Boyd
Avenal, California, USA

Most of the gliders I've flown have the tow release way
too far from my hand. Granted, I have short
arms (not a boxer), but do others commonly notice they
need to lean forward a little or twist shoulders to
pull the release on many gliders?

Get yourself a ski boot carrier. Its a length of 1/4" nylon cord with a
plastic handle. Wrap the cord around the existing release knob, and Voila, 8"
extra reach. Works great in my Jantar where the existing release is way
forward. Another benefit is I can loosely hold the plastic handle in my hand
with little risk of pulling the release by accident if I hit turbulence since
there is a lot of slack.

BTW, IMO, your hand should never be holding the release on the panel.
Instead, keep your hand just behind the release, basically with your knuckles
touching the release. This way, if you're waved off, you don't have to look
for the release, it is already at hand.





Jim Vincent
CFIG
N483SZ
illspam

I'd rather have my hand near the tow release instead, especially during the
first part of the tow.


Me too, what I meant to convey was.... if the spoilers are open and my
hand is not on the spoiler control handle it might be nice to have an
alarm sound. To me it matters not whether there is pressure on the tow
hook or not. It only matters that the spoliers are open and I am not
holding them open. I guess I'm thick, I haven't caught on why tow hook
pressure is important.

Me too, what I meant to convey was.... if the spoilers are open and my
hand is not on the spoiler control handle it might be nice to have an
alarm sound.

Interesting approach! I like it. Could easily be done.



To me it matters not whether there is pressure on the tow
hook or not. It only matters that the spoliers are open and I am not
holding them open. I guess I'm thick, I haven't caught on why tow hook
pressure is important.

Tow hook pressure was one parameter discussed in a spoiler warning solution.
Frankly, I like your idea of the hand sensor more.

Jim Vincent
CFIG
N483SZ
illspam