Open Spoilers Alarm on tow

"Bob Lepp" wrote in message
om...

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.

If I understand your proposal for a sensor to detect the pilots hand on the
spoiler handle correctly, it should fulfill the "spoiler open on tow"
warning function assuming no pilot would deliberately open the spoilers
while still on tow.

I do see a few problems that need a thoughtful review.

I have had pilots open the spoilers instead of pulling the release at the
top of a winch launch. A warning here would be nice.

It would create a problem if the pilot must move his hand from the spoilers
to the flaps to select a negative setting just after touchdown to maintain
aileron control. It would be a real nuisance to get a warning horn at that
busy moment.

Some gliders must start their takeoff roll with the spoilers open to augment
aileron control at low airspeeds. Again, it's a bad time to be distracted
by a audible warning. This is where a low airspeed lockout would be needed.

I think the system would need three sensors to give a useful warning -
airspeed above a certain value, ring in hook and spoiler open.

Bill Daniels

Good points.

I have had pilots open the spoilers instead of pulling the release at the
top of a winch launch. A warning here would be nice.

The 'Spoilers Open' alarm sounding means 'your hand is opening the
spoilers', since the other hand should/must be on the stick...let the
pilot figure out the rest?


It would create a problem if the pilot must move his hand from the spoilers
to the flaps to select a negative setting just after touchdown to maintain
aileron control. It would be a real nuisance to get a warning horn at that
busy moment.


This is a 'good thing', not a problem. If you're on the ground, a
'spoilers open' alarm can be ignored, just as I ignore the audible
stall warning horn on my ship. In fact I listen for it and worry if it
does NOT sound. Like checking warning lights for not being burned out.


Some gliders must start their takeoff roll with the spoilers open to augment
aileron control at low airspeeds. Again, it's a bad time to be distracted
by a audible warning. This is where a low airspeed lockout would be needed.

Ditto above, to me at least, I expect the alarm and want the alarm to
prove the alarm system is working. My stall warning on/off switch is
placarded as such, 'Switch on before takeoff' for that purpose I
believe.


I think the system would need three sensors to give a useful warning -
airspeed above a certain value, ring in hook and spoiler open.

Sure, that works well, then when they pop open just after you
release..... or after you forget to relock them after using them for
an in flight height reduction.... I have done this, it is
embarrassing!... at best.

I can't see how any of the proposed combinations could be a bad thing.
It just depends on cost to install, complexity and reliability I
guess. Heck, I don't even know how to sense the hand on the control
reliably! So a device to sense ring in or strain on hook boggles me. I
can see they would be expensive, tricky to do and likely cause some
paperwork for the authorities. But if they prevent one accident.....


Bill Daniels

Bill Daniels wrote:
I think the system would need three sensors to give a useful warning -
airspeed above a certain value, ring in hook and spoiler open.

If you add a $2 microcontroller to the system (or are clever with
relays) you could use a switch to sense that the release has been
pulled with airspeed above threshold, rather than trying to determine if
there is a ring in the hook...

Marc