From: Marc J. Zeitlin Subject: COZY: Cabin Air Exhaust?? Date: Tue, 2 Sep 97 13:09:36 EDT People; While I'm flooding the hyperspace waves, I've got a question. I recently got a ride in a mailing list member's L.E. This L.E. had the standard cabin air vent at the front of the canopy, however, as we took off, very little air was entering. I mentioned this (while losing 10 lbs. of sweat in the back seat) and asked about a cabin air exhaust port, and the owner said that there wasn't one - he just extended the landing light, and the leaks from around it would allow the air to exhaust. Well, it was immediately apparent to me when he would extend the L.L. - the volume of air entering would go up by an order of magnitude. As an engineer, the dual usage of an item for multiple purposes appeals to me from an economy standpoint, but I seriously doubt that extending the L.L. should be a permanent solution for this issue (not to mention that with my L.L.'s in the nose, there's nothing to extend :-) ). Seriously, it's pretty clear that an exhaust is required, but I've pored over the plans and couldn't find a word about this. In poking around at Oshkosh I saw a couple of positions (fuselage side under strake, under rear passenger's seat) for the exhaust, as well as reverse NACA vents or just angled holes, but I was wondering what other people are doing in this regard? What works well, and why? Does it matter? Thanks. -- Marc J. Zeitlin Email: marcz@an.hp.com by post.larc.nasa.gov (8.8.6/pohub4.1) with SMTP id OAA00869 for ; Tue, 2 Sep 1997 14:12:00 -0400 (EDT) Date: Tue, 02 Sep 1997 14:11:20 -0400 From: Paul Krasa Subject: Re: COZY: Cabin Air Exhaust?? At 13:09 9/2/97 EDT, Marc J. Zeitlin wrote: >People; > >While I'm flooding the hyperspace waves, I've got a question. I recently >got a ride in a mailing list member's L.E. This L.E. had the standard >cabin air vent at the front of the canopy, however, as we took off, very >little air was entering. I mentioned this (while losing 10 lbs. of sweat >in the back seat) and asked about a cabin air exhaust port, and the owner >said that there wasn't one - he just extended the landing light, and the >leaks from around it would allow the air to exhaust. Well, it was >immediately apparent to me when he would extend the L.L. - the volume of >air entering would go up by an order of magnitude. > >As an engineer, the dual usage of an item for multiple purposes appeals >to me from an economy standpoint, but I seriously doubt that extending >the L.L. should be a permanent solution for this issue (not to mention >that with my L.L.'s in the nose, there's nothing to extend :-) ). > >Seriously, it's pretty clear that an exhaust is required, but I've pored >over the plans and couldn't find a word about this. In poking around at >Oshkosh I saw a couple of positions (fuselage side under strake, under >rear passenger's seat) for the exhaust, as well as reverse NACA vents or >just angled holes, but I was wondering what other people are doing in >this regard? What works well, and why? Does it matter? > >Thanks. > >-- >Marc J. Zeitlin Email: marcz@an.hp.com > > Check out Debbie Iwate's (sp?)supplimental plans for the Long EZ. There is a neat exhuast idea in there. It is a simple idea based on the top of a shaker cheese lid. If you don't have a copy let me know and I will draw a picture and fax it to you. Debbie's plans are a must for Long EZ builders and would be a great addition to a Cozy builder's library. Paul Krasa Long EZ 214LP Date: Tue, 02 Sep 1997 11:19:18 -0700 From: "LCDR James D. Newman" Organization: INFINITY Aerospace Subject: COZY: Cockpit Exhaust Outlet Hi Marc and All, >Seriously, it's pretty clear that an exhaust is required, but I've pored over the plans and couldn't find a word about this. In poking around at Oshkosh I saw a couple of positions (fuselage side under strake, under rear passenger's seat) for the exhaust, as well as reverse NACA vents or just angled holes, but I was wondering what other people are doing in this regard? What works well, and why? Does it matter?< Bill Theeringer has the top of a parmesan cheese container / dispenser mounted in the back turtle deck of his Long-EZ-RG with an external low profile cover over it so water can't come in. Maybe Bill will comment on how well it works, how to install it, etc. Infinity's Forever, JD by InfoAve.Net (PMDF V5.1-8 #23426) with SMTP id <01IN65EYW2IQ9075GU@InfoAve.Net> for cozy_builders@hpwarhw.an.hp.com; Tue, 2 Sep 1997 14:34:12 EDT Date: Tue, 02 Sep 1997 14:32:12 -0400 From: Jeff S Russell Subject: Re: COZY: Cabin Air Exhaust?? Organization: AEROCAD INC. Marc J. Zeitlin wrote: > Seriously, it's pretty clear that an exhaust is required, but I was > wondering what other people are doing in this regard? > What works well, and why? Does it matter? Marc, I used what the Velocity does using the mainspar as a air passage through the bottom access hole to the wing nuts. A small boat windshield fairing covers both holes making a vacuum to pull out the air. I have installed whisper flow 2" vents on the instrument panel instead of the 1" size I had on my 3 place using NO Scat tube for a duct. I just made a fiberglass duct and the air flow with this system will blow your maps out of your hands. The other system was noisy because of the Scat tube and was not enough air in the cabin. The whisper flow are plastic and came from wicks and were about $15 each. The metal 1" jobbies were about $65 each and you could not give them to me :-) I forgot to say a hole is needed in the main spar bulkheads that are at the inboard hardpoints for the air to get out. I used the 3.125 hole saw that you just purchased. -- Jeff Russell/AeroCad Inc. E-mail: Jeff@aerocad.com Phone/ fax (call first): 910-961-2238 AeroCad: http://www.aerocad.com Composite workshop info: http://www.Sportair.com From: Marc J. Zeitlin Subject: Re: COZY: Cabin Air Exhaust?? (fwd) Date: Tue, 2 Sep 97 15:08:30 EDT Jeff Russell wrote: >Marc, I used what the Velocity does using the mainspar as a air passage >through the bottom access hole to the wing nuts. A small boat windshield >fairing covers both holes making a vacuum to pull out the air. This is an interesting scheme. I assume you've got to leave some air passage to the spar - you can't completely seal it up, even with some velcro covers. >.... I have >installed whisper flow 2" vents on the instrument panel instead of the >1" size I had on my 3 place using NO Scat tube for a duct. I just made >a fiberglass duct and the air flow with this system will blow your maps >out of your hands. Ahem. This is exactly what's called out in the COZY MKIV plans - when's the last time you looked at them ? :-). This is, of course, _exactly_ what I've got on my plane. I can get the air in - I just need to get rid of it after it's cooled me and I've breathed it :-). >The metal 1" jobbies were about $65 each and you could not give them to >me :-) They sure are pretty, though. The black plastic whisper-flo's are big and ugly :-). >I forgot to say a hole is needed in the main spar bulkheads that are at >the inboard hardpoints for the air to get out. I used the 3.125 hole >saw that you just purchased. Wow - sounds like massive overkill. Each vent is only 2" in diameter - I'd put a smaller hole in the bulkhead. Thanks for the info. -- Marc J. Zeitlin Email: marcz@an.hp.com From: Ken Reiter Date: Tue, 2 Sep 97 15:22:59 CDT Subject: Re: COZY: Cabin Air Exhaust?? (fwd) Hello Group, I used the solution from CSA. It uses a flap valve from FORD. Most cars have a flap that is behind something (rear turn lights/bumper/etc) and when air flows into the cabin it give an outlet. When you heat or high A/C it keeps the cabin air in. I just placed a reverse NACA scope on the bottom rear side (out of sight). Stay Cool, Ken Reiter CozyIII From: Lee Devlin Subject: Re: COZY: Cabin Air Exhaust?? Date: Tue, 2 Sep 97 14:56:46 MDT > While I'm flooding the hyperspace waves, I've got a question. I recently > got a ride in a mailing list member's L.E. This L.E. had the standard > cabin air vent at the front of the canopy, however, as we took off, very > little air was entering. I mentioned this (while losing 10 lbs. of sweat > in the back seat) and asked about a cabin air exhaust port, and the owner > said that there wasn't one - he just extended the landing light, and the > leaks from around it would allow the air to exhaust. Well, it was > immediately apparent to me when he would extend the L.L. - the volume of > air entering would go up by an order of magnitude. I guess that I should slither out from the cloak of anonymity that Marc so diligently prepared for me in this posting. I'd like to clear up some of the conditions under which it occurred. First of all, I did not open up the landing light, I cracked it about .25 inches. The previous owner taught me this trick. Secondly, I want to apologize to Marc for baking him in the back seat :-). With the canopy closed and no air flow, these planes can be like ovens inside. Whenever the heat has me feeling uncomfortable, I always keep in mind that this condition is only temporary since as soon as I level out, it will get much better. I also have the opportunity to climb to a nice cool altitude if things cannot be made better with airflow. The flip side of having good airflow is having a well sealed cabin when flying in cool weather. My LongEZ has no heater and so the previous owner spent a lot of time sealing up all the leaks. This means that you need to vent the plane better in the summer. I have considered putting in more vents, but the little trick of cracking open the landing light a little seems to work just fine. Lee Devlin | HP Greeley Division | Long EZ N36MX | 700 71st Ave. | Cozy MK IV under const. | Greeley, CO 80634 | (Chapter 10) From: CCady@aol.com Date: Tue, 2 Sep 1997 17:28:38 -0400 (EDT) Subject: Re: COZY: Cabin Air Exhaust?? In a message dated 97-09-02 14:16:15 EDT, you write: << eat) for the exhaust, as well as reverse NACA vents or just angled holes, but I was wondering what other people are doing in this regard? What works well, and why? Does it matter? >> Marc, On my former Long-Ez I installed a reverse NACA scoop on the right side roll-over near the passengers right cheek. They reported that on landing when the belly brake was lowered air would rush in the out vent near their face due to low pressure behind the speed brake. Air flow for them was a problem and I installed a vent for them in the lower strake skin near the fuselage with a plenum at the back of the front seat back. I had a NACA scoop which they said didn't move much air. I then fashioned a small forward facing scoop over it and they reported much better vent air coming in. I tend to think that a outlet vent is a good idea but nothing can beat a good forward facing scoop to force air in the vents. Cliff From: Gunrider@aol.com Date: Tue, 2 Sep 1997 17:57:39 -0400 (EDT) Subject: Re: COZY: Cabin Air Exhaust?? I couldn't agree more - I live in Florida and have been researching the whole cooling problem. I am going to use the Aerocad canopy to reduce plexi area, have at least four naca scoops for passenger cooling - still looking for the best place considering all things... I.E. short or no hoses, little or no bending of ducts, shape and size of nacas. The exhaust for cooling air I have found to be extremely important. Without it you end up with a higher pressure cabin and little or no airflow. I am currently on ch.13 and think I am going to use the existing holes around the struts to vent exhaust. The problem is getting sufficient volume of air past the rear seats to the strut area above the strut cover and eventually to the strut holes. I am going for the 15% greater area of exhaust hole size/flow to get turbo type fllow from my cooling vents. One thought is to place some kind of ducting(smooth glass not hose) behind and to the sides of the rear passengers heads to aid in cooling the upper rear of the cabin. I as well would appreciate additional info on venting currently used. Anyone use the naca vents that screw to close flush on the outside? A freind is using a bilge blower to cool at taxi etc. in his Velocity. It ads weight but not a bad idea. KEEP THE INFORMATION FLOWING GUYS - I LOVE THIS MEDIUM!!!!!!!!!!! Hugh Farrior From: cdenk@ix.netcom.com Date: Tue, 2 Sep 1997 18:09:22 -0500 (CDT) Subject: Re: COZY: Cabin Air Exhaust?? (fwd) On 09/02/97 15:08:30 you wrote: > >Jeff Russell wrote: > >>Marc, I used what the Velocity does using the mainspar as a air passage >>through the bottom access hole to the wing nuts. A small boat windshield >>fairing covers both holes making a vacuum to pull out the air. > >This is an interesting scheme. I assume you've got to leave some air >passage to the spar - you can't completely seal it up, even with some >velcro covers. > >>.... I have >>installed whisper flow 2" vents on the instrument panel instead of the >>1" size I had on my 3 place using NO Scat tube for a duct. I just made >>a fiberglass duct and the air flow with this system will blow your maps >>out of your hands. > >Ahem. This is exactly what's called out in the COZY MKIV plans - when's >the last time you looked at them ? :-). This is, of course, _exactly_ >what I've got on my plane. I can get the air in - I just need to get rid >of it after it's cooled me and I've breathed it :-). > >>The metal 1" jobbies were about $65 each and you could not give them to >>me :-) > >They sure are pretty, though. The black plastic whisper-flo's are big >and ugly :-). > >>I forgot to say a hole is needed in the main spar bulkheads that are at >>the inboard hardpoints for the air to get out. I used the 3.125 hole >>saw that you just purchased. > >Wow - sounds like massive overkill. Each vent is only 2" in diameter - >I'd put a smaller hole in the bulkhead. > >Thanks for the info. > >-- >Marc J. Zeitlin Email: marcz@an.hp.com > > THe wing/spar area is open to the engine compartment, I find soot from the engine area (oily) in the area, plus pulling more vacuum in the area would pull a fire that direction if there ever was one, and though rare the do happen. Remember, all fuel and oil hoses should be teflon with fire shield. Varga Aircraft in the Southwest does a excellent job of furnishing TSO,d at reasonable cost. Date: Tue, 02 Sep 1997 19:46:57 -0400 From: Paul Burkhardt Subject: COZY: Re: cabin air exhaust I recall seeing a tube runnig alongside the exhaust pipes that ran to the firewall via scat tubing. I believe the idea is to use the prop to "pull" the air from the cabin. Maybe I'm confusing this with a breather tube, however It would seem to work (on paper anyway). I could think of fire as being a potental problem and I suppose it could be insulated against it? What ya'll think...Paul Burkhardt From: cdenk@ix.netcom.com Date: Tue, 2 Sep 1997 20:26:44 -0500 (CDT) Subject: Re: COZY: Re: cabin air exhaust On 09/02/97 19:46:57 you wrote: > >I recall seeing a tube runnig alongside the exhaust pipes that ran to >the firewall via scat tubing. I believe the idea is to use the prop to >"pull" the air from the cabin. Maybe I'm confusing this with a breather >tube, however It would seem to work (on paper anyway). I could think of >fire as being a potental problem and I suppose it could be insulated >against it? What ya'll think...Paul Burkhardt > > The minimum penetrations (holes) in the firewall the better safety, plus weight penalty. I have gill reverse scoops by making the turtleback 3/4" wider each side than the cowling x 4" high going to 0". They seem to work well, since I have plenty of summer ventilation, and can fly in short sleeves in the winter here in Cleveland. From: "Johnson, Phillip" Subject: RE: COZY: Cabin Air Exhaust?? Date: Tue, 2 Sep 1997 21:37:08 -0400 The problem with the heating and ventilation system for all of the canard pushers is that only warm/cold air ingress is considered. The egress is supposed to happen through leaks in the various interfaces. Essentially the cockpit is pressurized until something gives. Providing a low pressure point to cause the air to escape in a controlled fashion not only improves the heating and ventilation, it reduces the noise since the cockpit is now at a lower pressure than the outside world. This results in the canopy being compressed on its seals cutting down on noise and drag. I have been thinking over this one for some time and I have concluded that the optimum place for the exit vent is just behind the FS 0 bulkhead. Since the new warm/cold air enters the cabin from the rear (excluding the face vents), the forward placed vents will cause the air to move forward through the cabin, down past the pilot's, and co-pilot's legs, to the exit vent, thereby keeping feet warm in winter and cool in summer. Placing exit vents from the heat duct behind the front seats into the cabin (i.e. near the rear passengers feet) will encourage warm air to pass over the passengers feet before passing the pilots head then onto the FS 0 bulkhead vents. I have also added overhead vents in the cabin to enhance the heating in the Canadian winters. There is a second benefit of this FS 0 exit location and that is that it provides drainage in the event of water leaks in the parked nose down condition. The vent type, reverse NACA, or whatever is open to the discussion but I think that scheme will work but is yet to be proven. My $0.02 worth. Phillip Johnson Date: Wed, 03 Sep 1997 08:44:42 +0200 From: Rego Burger Subject: COZY: Cabin Air Exhaust?? -Reply Simple test to convince you of the need for this, open the vents on your car on the freeway without the fan on, keep the windows closed and feel the flow, now open one window just a peek (tiny bit) You will see a difference. For me on the COZY I was thinking of a hole in the gear cover as we have two holes leading that way....as the gear cover is a high pressure area for engine cooling it may be wise to make a scoop face rearwards, the air flow will help extract the cabin air....? How much these scoops will effect the engine cooling flow I'm not certain of? More ideas welcome. Rego Burger CZ4#139 RSA Date: Wed, 03 Sep 1997 10:13:12 +0200 From: Rego Burger Subject: COZY: More on airflow..RE: cooling! We all agree by now that for engine cooling to work well, the outlet should be larger than the inlet not so? Well maybe this applies to the cabin cooling too! So then the outlet vent should be marginally bigger than the inlets...? Food for thought. Nice forum .. stretching the brainwaves again hey! Rego CZ4#139 RSA From: Marc J. Zeitlin Subject: COZY: Re: cabin air exhaust (fwd) Date: Wed, 3 Sep 97 11:42:31 EDT Paul Burkhardt wrote: >I recall seeing a tube runnig alongside the exhaust pipes that ran to >the firewall via scat tubing. I believe the idea is to use the prop to >"pull" the air from the cabin. Maybe I'm confusing this with a breather >tube........... Nope - you're confusing this with the heater muff duct to the heat duct in the center console. Sort of cabin air, I guess, but in, not out. We've seen a lot of interesting ideas for exit air - Ken Reiter is going to send me an article out of an old CSA mag. that describes one technique. If it doesn't violate the Fair Use Doctrine, I'll scan it in and make it available on the web pages. -- Marc J. Zeitlin Email: marcz@an.hp.com