Hobbs Meter with Airspeed activation

Hi,

I have a customer that has 2 2-seat (ASK-21) gliders for a commercial
operation. He is trying to find for them "Hobbs meters" with switches that
start allow the meter to record time only when in flight (over some airspeed
threshold). Of course, it would not be ideal if it recorded when on the
ground on a windy day.

Any suggestions?

I found some Hobbs meters with part number 85000C12 which operate on 10 to
30 VDC. But the switch is the tough part.

Best Regards,

Paul Remde
Cumulus Soaring, Inc.

Why not install a GPS logger? It should be relatively easy to download the
data, and then parse it to give times of use. Something like FlyWithCE even
has software to log your times.

Peter

"Paul Remde" wrote in message
...
Hi,

I have a customer that has 2 2-seat (ASK-21) gliders for a commercial
operation. He is trying to find for them "Hobbs meters" with switches
that start allow the meter to record time only when in flight (over some
airspeed threshold). Of course, it would not be ideal if it recorded when
on the ground on a windy day.

Any suggestions?

I found some Hobbs meters with part number 85000C12 which operate on 10 to
30 VDC. But the switch is the tough part.

Best Regards,

Paul Remde
Cumulus Soaring, Inc.

On Aug 29, 12:36*pm, "Peter von Tresckow" wrote:
Why not install a GPS logger? It should be relatively easy to download the
data, and then parse it to give times of use.

Agreed. Except the customer in question probably wants to know the
flight time immediately after Joe Glider Pilot 1 lands so that he can
pay and leave. Also, the sooner Joe Glider Pilot 2 can fly the better.
This would make the "download" part less than convenient.

My suggestion: ask the XCsoar guys to implement a "total time in
flight" feature. Then install it on a cheap car GPS and add a battery
pack.

Bart

I know you don't sell LX vario's anymore Paul but the LX16-D has a
built in flight timer function and is a nice little audio vario to
boot. I put an LX16 in the Cherokee this season and have enjoyedit so
far.

http://www.lxavionics.co.uk/variometers.htm

On Aug 29, 3:09*pm, Tony wrote:
I know you don't sell LX vario's anymore Paul but the LX16-D has a
built in flight timer function and is a nice little audio vario to
boot. *I put an LX16 in the Cherokee this season and have enjoyedit so
far.

http://www.lxavionics.co.uk/variometers.htm

another possible solution, and actually more in line with the original
question and price range, would be to work out some sort of weight on
wheels switch on the glider to run to the Hobbs meter linked.

On Mon, 29 Aug 2011 14:51:57 -0500, Bart wrote:


My suggestion: ask the XCsoar guys to implement a "total time in
flight" feature. Then install it on a cheap car GPS and add a battery
pack.

Bart

XC Soar already has a built-in flight timer (parameter "Time of Flight").
This can be displayed in any of the infoboxes.


--
Stefan Murry

On Aug 29, 1:14*pm, "S. Murry" wrote:
XC Soar already has a built-in flight timer (parameter "Time of Flight"). *
This can be displayed in any of the infoboxes.

It does, indeed. But to be Hobbs equivalent it would have to be
"total" or "cumulative" time of flight.

Bart

Not yet available in USA IIRC:
http://dittolog.com/learn-about-dittolog/

Best Regards, Dave

On Mon, 29 Aug 2011 15:18:41 -0500, Bart wrote:



It does, indeed. But to be Hobbs equivalent it would have to be
"total" or "cumulative" time of flight.

Bart

True. Getting back to Paul's original question, how about using a pitot
tube to a pressure switch. There are pressure switches made for HVAC
ducts that are rated for pretty low pressure (quick search on Grainger
revealed some that actuate with as little as 0.02 in WC pressure). Quick
pitot calculation reveals that 20 MPH = 50 Pascals pitot pressure, or
about 0.2 " WC, so such a switch should work.
--
Stefan Murry

This calculator will help you work out the pitot pressures for different
speeds.
http://chrusion.com/BJ7/ASICalc.html
Aircraft Spruce sell a range of suitable pressure switches, calibrated to
your requirements, that can be firred to a pitot circuit..

I've flown several aircraft with Hobbs displaying time in the air - mainly
for maintenance purposes. Some used the aircraft's main pitot (ASI) -
others had a separate pitot for the Hobbs.


At 20:45 29 August 2011, S. Murry wrote:
On Mon, 29 Aug 2011 15:18:41 -0500, Bart wrote:



It does, indeed. But to be Hobbs equivalent it would have to be
"total" or "cumulative" time of flight.

Bart

True. Getting back to Paul's original question, how about using a pitot

tube to a pressure switch. There are pressure switches made for HVAC
ducts that are rated for pretty low pressure (quick search on Grainger
revealed some that actuate with as little as 0.02 in WC pressure). Quick

pitot calculation reveals that 20 MPH = 50 Pascals pitot pressure, or
about 0.2 " WC, so such a switch should work.
--
Stefan Murry