Air Extractor: Better than a Plastic Jesus?

I had one installed in my 27, 2 years ago. What I know for su The cockpit is a lot quieter without the noisy front vent (it is taped closed under the flapper). The performance of the side eyeball vent is greatly enhanced, and it blows a very nice stream of air towards my face when desired. So the cockpit is quieter and more comfortable. Most of our flights are flow fairly low in pretty humid air, so this is a big feature. The cone of silence behind you head makes sure that the air being exhausted comes from the cockpit, and not from the tail boom. It also doubles as a moose call if you land out and need to start living off the land while waiting for your retrieve crew. What I surmise: the performance gain is there, however my poor decision making would make it very hard for me actually put a number on it. It's not going to turn you into a wizard.

Schleicher TM/TN numbers for the vent:

ASW24: 18
ASW27: 15
ASW28: 7
ASG29: 4

Jim

If it improves performance why do Schempp and Schleicher not instal it?


I believe all new schleichers do come with it from the factory now, not sure about others but good chance they do these have really caught on the last couple years.

On Monday, December 16, 2013 7:06:18 PM UTC-5, waremark wrote:
If it improves performance why do Schempp and Schleicher
not instal it? They work very hard for improved performance.

Well, its a factory option for Antares, and excepting the
Antares located in Canada and north-west, all Antares in
North America have these vents. The exit duct improves cockpit
ventilation, and prevents air leaking out where it shouldn't
(a performance issue with nose intake and inadequate exhaust).


On Monday, 16 December 2013 19:23:31 UTC, Craig Funston wrote:
If Dick Butler believes in it, that's good enough for me :-)

Lange copied Dick, as did Schleicher ;-)
Some details he
http://www.nadler.com/public/2008_Uv...valde2008.html


See ya, Dave "YO electric"

On Monday, December 16, 2013 12:17:44 PM UTC-6, Papa3 wrote:
Not quite the direct answer you're looking for, but you do know that DG seems to think that venting cockpit air matters, right?



http://www.dg-flugzeugbau.de/index.p...dl-absaugung-e



On the theory that the Nixon Air Extractor had a better chance of working than the Plastic Jesus, I installed one two winters ago. Obvious improvement in cockpit airflow and decrease in canopy noise at high speed suggest it's doing "something". I built a little foam block with a string attached and plan to do some testing on cockpit pressure at speed with/without the exit orifice available. Expect to be able to show increased cockpit pressure with my handy-dandy NK Kestrel Wx meter and also see if there is measurable outflow by locating the Kestrel in the exit area. All that proves is a first-order measurement (i.e. something is happening due to the vent). In terms of performance measurement, maybe faith (along with the Plastic Jesus) is justification enough?



P3



On Sunday, December 15, 2013 6:51:45 PM UTC-5, wrote:

On Sunday, December 15, 2013 1:01:20 PM UTC-5, wrote:



Noticing all the openings behind the cockpits of mainly Schleicher gliders such as -27 and 29's I'm asking myself if this is a real drag reducer or a placebo. For those unfamiliar: people have been cutting 4x2 openings into the fuselage about 8" behind the canopy cutout and put air vents - some with funnel-like contraptions on the inside of the turtle deck into their gliders. The funnel seems to suggest to the air molecules "this way out", some pilots may put arrow stickers on the inside so the air knows which way to flow. The whole thing is meant to avoid pressurizing the cockpit from the front air vent. Air leaking from the canopy seal would trip outside air flow to become turbulent. Are there any serious comparison flights that were done following a scientific protocol to show the effect of such devices? Is this really better than putting a Tibetan prayer flag on the tail or a plastic Jesus on the glare shield? The latter can serve double purpose since I know where I would stick my transponder or PFlarm antenna... Seriously, I'd be interested if anyone has found this thing useful beyond the statement that it must be good since all these hotshot pilots (insert call signs here) have one. I'm waiting with jigsaw in hand for your responses, the LS8 rests uneasily in the basement! Herb, J7







Ask Erik Mann his opinion. He has one in his LS-8.



UH

Eric,

I'm quite aware of the DG publications on their air extractor (Mandl Absaugung or Mandl Sucker)and now read with interest that you have Nixon Extractor in your LS8. DG is claiming an incredible 2 glide point increase in performance on the LS10 with the extractor. I'm wondering if you had to adjust the polar in your glide computer to account for the better performance? My interest in this modification was raised after seeing nearly all '27 and '29s at New Castle this year with Nixon Extractors.
For those questioning why Schleicher seems slow in putting these into new gliders: re-certifying even such a small change with the Luftfahrtbundesamt and the EASA takes a lot of time. Looks like DG puts these into all of the few LS gliders they are building these days - but not into the DG 808.
Maybe I should get the Nixon Extractor AND the Plastic Jesus!

Herb

I have two different fuselage air extractors on my LS8-18. The reason I did this is because I knew my cockpit was being pressurised because the canopy vent would pop open at 100kts and no air was entering the cockpit thru that now open vent.

The first one I installed was the then "holy grail" of extractors, the Mandle. This was installed as instructed by DG on the lower fuselage just aft of the gear doors. This was a hastle mainly because I had to enroll in the DG maintenance program to be able to buy the installation kit. Bottom line...NO CHANGE IN NOISE LEVELS IN THE COCKPIT AND NO CHANGE IN CANOPY AIR VENT POPPING OPEN AT 100KTS.

I then had Rex install the locally sourced airvent that is placed on the top of the fuselage just behind the canopy. Immediately quieter cockpit. Now I could feel air moving past my face when the forward vent was opened. The canopy airvent stays closed right up to redline.

Did it improve my L/D by 10 points? Can't tell you.

Indeed the external shape of the JS1 fuselage is a direct (and
apparently authorised) copy of the ASW26. The brothers started modifying
one that needed two new wings.
Internally it is somewhat different.

The "mould" is still gracing our skies and was for sale last I saw...

Bruce


On 2013/12/15 11:28 PM, waremark wrote:
The JS1 fuselage looks to me identical to the ASH 26 but with extractor vents added. There might be a problem with having the vents - it would make me feel guilty about putting the stuff I like to take with me on the luggage deck. Look forward to hearing whether anyone knows whether they really make a difference.


On Sunday, 15 December 2013 18:15:23 UTC, JS wrote:
Isn't it a bit cold to be discussing air vents?



Believe Guy has one in his LS8/18.

Uncle Hank might know something about this.

Perhaps ask Dick Butler or the Jonker brothers.

If you have paid "LS tax", try DG.

They really suck. The extractor, of course.

Jim


--
Bruce Greeff
T59D #1771

http://www.ebay.com/itm/like/150944329699?lpid=82

The plastic Jesus might be cheaper, and it might help with a prayer for a divine thermal!

On Tuesday, December 17, 2013 8:56:35 AM UTC-6, wrote:

I then had Rex install the locally sourced airvent that is placed on the top of the fuselage just behind the canopy. Immediately quieter cockpit. Now I could feel air moving past my face when the forward vent was opened. The canopy airvent stays closed right up to redline.



Did it improve my L/D by 10 points? Can't tell you.

I'm seriously considering installing one on my LS6b this winter - where did you get yours from?

Kirk
66

On Tuesday, December 17, 2013 9:55:32 AM UTC-5, wrote:
On Monday, December 16, 2013 12:17:44 PM UTC-6, Papa3 wrote: Not quite the direct answer you're looking for, but you do know that DG seems to think that venting cockpit air matters, right? http://www.dg-flugzeugbau.de/index.p...dl-absaugung-e On the theory that the Nixon Air Extractor had a better chance of working than the Plastic Jesus, I installed one two winters ago. Obvious improvement in cockpit airflow and decrease in canopy noise at high speed suggest it's doing "something". I built a little foam block with a string attached and plan to do some testing on cockpit pressure at speed with/without the exit orifice available. Expect to be able to show increased cockpit pressure with my handy-dandy NK Kestrel Wx meter and also see if there is measurable outflow by locating the Kestrel in the exit area. All that proves is a first-order measurement (i.e. something is happening due to the vent). In terms of performance measurement, maybe faith (along with the Plastic Jesus) is justification enough? P3 On Sunday, December 15, 2013 6:51:45 PM UTC-5, wrote: On Sunday, December 15, 2013 1:01:20 PM UTC-5, wrote: Noticing all the openings behind the cockpits of mainly Schleicher gliders such as -27 and 29's I'm asking myself if this is a real drag reducer or a placebo. For those unfamiliar: people have been cutting 4x2 openings into the fuselage about 8" behind the canopy cutout and put air vents - some with funnel-like contraptions on the inside of the turtle deck into their gliders. The funnel seems to suggest to the air molecules "this way out", some pilots may put arrow stickers on the inside so the air knows which way to flow. The whole thing is meant to avoid pressurizing the cockpit from the front air vent. Air leaking from the canopy seal would trip outside air flow to become turbulent. Are there any serious comparison flights that were done following a scientific protocol to show the effect of such devices? Is this really better than putting a Tibetan prayer flag on the tail or a plastic Jesus on the glare shield? The latter can serve double purpose since I know where I would stick my transponder or PFlarm antenna... Seriously, I'd be interested if anyone has found this thing useful beyond the statement that it must be good since all these hotshot pilots (insert call signs here) have one. I'm waiting with jigsaw in hand for your responses, the LS8 rests uneasily in the basement! Herb, J7 Ask Erik Mann his opinion. He has one in his LS-8. UH Eric, I'm quite aware of the DG publications on their air extractor (Mandl Absaugung or Mandl Sucker)and now read with interest that you have Nixon Extractor in your LS8. DG is claiming an incredible 2 glide point increase in performance on the LS10 with the extractor. I'm wondering if you had to adjust the polar in your glide computer to account for the better performance? My interest in this modification was raised after seeing nearly all '27 and '29s at New Castle this year with Nixon Extractors. For those questioning why Schleicher seems slow in putting these into new gliders: re-certifying even such a small change with the Luftfahrtbundesamt and the EASA takes a lot of time. Looks like DG puts these into all of the few LS gliders they are building these days - but not into the DG 808. Maybe I should get the Nixon Extractor AND the Plastic Jesus! Herb

Approval of the ES Vent in Schleicher 24,27,28,29 took about 5 months which is pretty darned quick. Subsequently Schleicher has built mold inserts to allow implementation as part of new construction.
Variations have been installed in ASW-20, ASW-19, LS-8, Lak 17,Discus B, and Ventus B. Most are available from Eastern sailplane.
The vent insrt is common, however the collector that we consider important to the functionality of the system is unique to each type.
The FAA has determined that it agrees with Schleicher that this is a minor modification.
FWIW
UH