Cockpit ventilation

I was hoping to work on sealing the canopy frame, control connections
etc, as well as adding an air exhaust to increase the ventilation.
If I were to increase the ventilation in the cockpit and try various
options can you think of any easy ways to test and compare how
effective different options are?
Is there some easy way to measure airflow coming in [at a certain air
speed] on one flight versus a later flight?

Chris

On Jun 10, 7:22*pm, chris wrote:
I was hoping to work on sealing the canopy frame, control connections
etc, as well as adding an air exhaust to increase the ventilation.
If I were to increase the ventilation in the cockpit and try various
options can you think of any easy ways to test and compare how
effective different options are?
Is there some easy way to measure airflow coming in [at a certain air
speed] on one flight versus a later flight?

Chris

Hi Chris.
I've made only one modifcation to my Speed Astir. It's a 'Mandl
Extractor' vent to let air out. Subjectively, I know I'm a lot cooler
in the cockpit. I haven't done this yet, but here's what I'm going to
do to verify my subjective observation. I have set up a water
manometer that indicates the difference between cabin pressure and the
static system. I'll fly with my Extractor in place, but with the
inside opening taped over. After noting the manometer at 2 or 3
airspeeds/alititudes, I'll climb back up and repeat, after ripping the
tape off the extractor. I don't expect spectacular numbers, but if it
just confirms a small drop in cabin pressure relative to the static
system, I'll continue to use it. If it indicates my 'subjective'
observations are wishful thinking, I'll... still use it because I
THINK it works (even if I'm wrong!)

UF is about to get bombarded with requests for his extractor mod...
I wonder if he can make a video of this like the one for his trailer
jack mod?
Including the contortions required to rip off of the tape!
Here's Jim's trailer jack in action:
http://www.youtube.com/watch?v=YP2AD8rtdpA
Jim

Hi Chris.
I've made only one modifcation to my Speed Astir. *It's *a 'Mandl
Extractor' vent to let air out. *Subjectively, I know I'm a lot cooler
in the cockpit. *I haven't done this yet, but here's what I'm going to
do to verify my subjective observation. *I have set up a water
manometer that indicates the difference between cabin pressure and the
static system. *I'll fly with my Extractor in place, but with the
inside opening taped over. *After noting the manometer at 2 or 3
airspeeds/alititudes, I'll climb back up and repeat, after ripping the
tape off the extractor. *I don't expect spectacular numbers, but if it
just confirms a small drop in cabin pressure relative to the static
system, I'll continue to use it. *If it indicates my 'subjective'
observations are wishful thinking, I'll... still use it because I
THINK it works (even if I'm wrong!)

I also made a Mandle Exctractor, (as well as a Butler Extractor, which
is what I actually use on my SZD-59 although the Mandle I made works
just fine too... both really provide a night and day difference
compared to no exhaust exit, but have made no real measurements as to
actual performance...) and if Fuzz doesn't feel like molding up some,
I would be happy to. In the process of researching different aspects
on the subject, I made some discoveries and added some refinements as
well to the inlet of this outlet, to efficiently accommodate a
honeycomb grill of strategic proportions rather than putting a mere
piece of mesh there to 'keep out the critters' as DG/LS put it but did
not change the Mandle designed portion of it and of course it could be
easily made as a normal one by removing the bell-mouth inlet and
honeycomb flange...

Tomorrow when I have more time I will post my synopsis on the
subject...

-Paul

On Jun 10, 8:50*pm, sisu1a wrote:
Hi Chris.
I've made only one modifcation to my Speed Astir. *It's *a 'Mandl
Extractor' vent to let air out. *Subjectively, I know I'm a lot cooler
in the cockpit. *I haven't done this yet, but here's what I'm going to
do to verify my subjective observation. *I have set up a water
manometer that indicates the difference between cabin pressure and the
static system. *I'll fly with my Extractor in place, but with the
inside opening taped over. *After noting the manometer at 2 or 3
airspeeds/alititudes, I'll climb back up and repeat, after ripping the
tape off the extractor. *I don't expect spectacular numbers, but if it
just confirms a small drop in cabin pressure relative to the static
system, I'll continue to use it. *If it indicates my 'subjective'
observations are wishful thinking, I'll... still use it because I
THINK it works (even if I'm wrong!)

I also made a Mandle Exctractor, (as well as a Butler Extractor, which
is what I actually use on my SZD-59 although the Mandle I made works
just fine too... both really provide a night and day difference
compared to no exhaust exit, but have made no real measurements as to
actual performance...) and if Fuzz doesn't feel like molding up some,
I would be happy to. In the process of researching different aspects
on the subject, I made some discoveries and added some refinements as
well to the inlet of this outlet, to efficiently accommodate a
honeycomb grill of strategic proportions rather than putting a mere
piece of mesh there to 'keep out the critters' as DG/LS put it but did
not change the Mandle designed portion of it and of course it could be
easily made as a normal one by removing the bell-mouth inlet and
honeycomb flange...

Tomorrow when I have more time I will post my synopsis on the
subject...

-Paul

Paul's is vastly more sophisticated than mine!
Here's a link to a picture of mine:
http://griderpirate.smugmug.com/gall...55235771_pv8zu

JS, Hi! Pulling the tape is easy. I actually made a snug fitting
floor-mat foam plug to tape in place. I fitted it with a string for
removing in-flight. Tape/string would work too, but I realized I need
a plug to keep critters out when I'm not flying.

On Jun 10, 11:50*pm, sisu1a wrote:
Hi Chris.
I've made only one modifcation to my Speed Astir. *It's *a 'Mandl
Extractor' vent to let air out. *Subjectively, I know I'm a lot cooler
in the cockpit. *I haven't done this yet, but here's what I'm going to
do to verify my subjective observation. *I have set up a water
manometer that indicates the difference between cabin pressure and the
static system. *I'll fly with my Extractor in place, but with the
inside opening taped over. *After noting the manometer at 2 or 3
airspeeds/alititudes, I'll climb back up and repeat, after ripping the
tape off the extractor. *I don't expect spectacular numbers, but if it
just confirms a small drop in cabin pressure relative to the static
system, I'll continue to use it. *If it indicates my 'subjective'
observations are wishful thinking, I'll... still use it because I
THINK it works (even if I'm wrong!)

I also made a Mandle Exctractor, (as well as a Butler Extractor, which
is what I actually use on my SZD-59 although the Mandle I made works
just fine too... both really provide a night and day difference
compared to no exhaust exit, but have made no real measurements as to
actual performance...) and if Fuzz doesn't feel like molding up some,
I would be happy to. In the process of researching different aspects
on the subject, I made some discoveries and added some refinements as
well to the inlet of this outlet, to efficiently accommodate a
honeycomb grill of strategic proportions rather than putting a mere
piece of mesh there to 'keep out the critters' as DG/LS put it but did
not change the Mandle designed portion of it and of course it could be
easily made as a normal one by removing the bell-mouth inlet and
honeycomb flange...

Tomorrow when I have more time I will post my synopsis on the
subject...

-Paul

Please do, I am interested in making a replacement hatch for my Grob
also, but have no experience molding fiberglass.

Todd

On Jun 10, 11:17*pm, Uncle Fuzzy wrote:

Subjectively, I know I'm a lot cooler
in the cockpit.

Think that's all about that 101 Dalmatians beach towel. The extractor
is irrelevant.

-T8

Chris,

I used a handheld anemometer (Kestrel or La Crosse) set on meters/second to
quantify the flow from a cockpit vent when I was improving the flow in my
first glider.

As suggested by others, a manometer would work as well, but I had the
anemometer handy. You do have to measure at the same distance form the vent
each time, of course.

bumper


"chris" wrote in message
...
I was hoping to work on sealing the canopy frame, control connections
etc, as well as adding an air exhaust to increase the ventilation.
If I were to increase the ventilation in the cockpit and try various
options can you think of any easy ways to test and compare how
effective different options are?
Is there some easy way to measure airflow coming in [at a certain air
speed] on one flight versus a later flight?

Chris

bumper wrote:
Chris,

I used a handheld anemometer (Kestrel or La Crosse) set on meters/second to
quantify the flow from a cockpit vent when I was improving the flow in my
first glider.

As suggested by others, a manometer would work as well, but I had the
anemometer handy. You do have to measure at the same distance form the vent
each time, of course.

bumper


"chris" wrote in message
...
I was hoping to work on sealing the canopy frame, control connections
etc, as well as adding an air exhaust to increase the ventilation.
If I were to increase the ventilation in the cockpit and try various
options can you think of any easy ways to test and compare how
effective different options are?
Is there some easy way to measure airflow coming in [at a certain air
speed] on one flight versus a later flight?

Because IGC loggers are vented to the cockpit and respond more rapidly
to small pressure changes than a mechanical altimeter, you might be able
to test the pressure difference with your logger. While flying at a
steady speed, open/close the vent, while noting the change in altitude.
Later, you can convert the altitude change to pressure changes.

I suggest a 1 second logging rate if you want to record the tests.


--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* Sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

Because IGC loggers are vented to the cockpit and respond more rapidly
to small pressure changes than a mechanical altimeter, you might be able
to test the pressure difference with your logger. While flying at a
steady speed, open/close the vent, while noting the change in altitude.
Later, you can convert the altitude change to pressure changes.

Well that probably won't help me as much since i want to compare
between 2 different flights. The configuration change is not easily
done while flying so i wanted to compare two different flights.
But I might be able to open and close the front vent and see if there
is a pressure change on my volkslogger at a certain airspeed and
altitude. Then look for the delta on the next flight.

Chris