KR> Sucking air - Oil temp problem
Dan I finished up putting a low flat 2 cm high by 12 cm long scoop in the cowl above the oil cooler like you see in some hotted up car bonnets. Also added a flange to the exit hole underneath as others suggest. The extra cooling was evident in lower temperatures but also in drag and cruise speed. John Martindale 29 Jane Circuit TOORMINA NSW 2452 AUSTRALIA phone: 61 2 66584767 (H) 61 2 66869075 (W) mobile: 0403 049990 email:johnja...@optusnet.com.au web: www.members.optusnet.com.au/johnjanet/Martindale.htm - Original Message - From: "Dan Heath" To: Sent: Monday, October 16, 2006 4:23 AM Subject: KR> Sucking air - Oil temp problem > Well, I originally planned to build a plenum behind the oil cooler
KR> Sucking air - Oil temp problem
"Then one of guys at the airport, who's opinion I greatly respect, convinced me to make an "air grabber" of sorts, and force the air into a plenum in front of the oil cooler." This is the best way to go. Granted it may not be the easiest. The "feeder" duct does not have to be round. A flat but wide duct can supply the same amount of air. If your space is very restricted you could even use two ducts half the height as one and merge them into the plenum prior to the cooler. These ducts could be fabricated into the inside top of the cowling. The location of the inlet is the critical thing. From the centerline of the spinner and lower will give the best results. You could even partition off part of the normal cooling air inlets and plumb this air to the cooler. If you put the inlet any higher or on top of the cowling you could get reverse air flow at high angles of attack like climb out when you need the cooling most. Stephen Teate Paradise, Texas
KR> Sucking air - Oil temp problem
Good point. I'll have to wool tuft my inlet on top of the cowl and check that out. I know there is a area of at least neutral pressure close to the canopy leading edge as the air zooms over the top but my inlet is about 16" forward of that. John Martindale 29 Jane Circuit TOORMINA NSW 2452 AUSTRALIA phone: 61 2 66584767 (H) 61 2 66869075 (W) mobile: 0403 049990 email:johnja...@optusnet.com.au web: www.members.optusnet.com.au/johnjanet/Martindale.htm - Original Message - From: "Stephen Teate" To: "KRnet" Sent: Monday, October 16, 2006 11:59 PM Subject: RE: KR> Sucking air - Oil temp problem > > > "Then one of guys at the airport, > who's opinion I greatly respect, convinced me to make an "air grabber" > of > sorts, and force the air into a plenum in front of the oil cooler." > > This is the best way to go. Granted it may not be the easiest. The > "feeder" duct does not have to be round. A flat but wide duct can supply > the same amount of air. If your space is very restricted you could even > use two ducts half the height as one and merge them into the plenum > prior to the cooler. These ducts could be fabricated into the inside top > of the cowling. The location of the inlet is the critical thing. From > the centerline of the spinner and lower will give the best results. You > could even partition off part of the normal cooling air inlets and plumb > this air to the cooler. If you put the inlet any higher or on top of the > cowling you could get reverse air flow at high angles of attack like > climb out when you need the cooling most. > > Stephen Teate > Paradise, Texas > > ___ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html
KR> Sucking air - Oil temp problem
Well, I originally planned to build a plenum behind the oil cooler and duct it to a venturi on the bottom of the cowl. Then one of guys at the airport, who's opinion I greatly respect, convinced me to make an "air grabber" of sorts, and force the air into a plenum in front of the oil cooler. I tried every way I could and could not find enough room to put the intake hose into the plenum, or to route and secure the intake hose where it would get a lot of air. So, back to the first plan, and figure out the venturi as the plenum was already configured. Well, that was getting very complicated as there is not much room inside the cowling, due to the crossover exhaust. So, I decided to put two 2" aluminum tubes through the bottom of the cowl, sort of like very short exhaust pipes, to which I will run my air ducts from the plenum, behind the oil cooler. These will protrude somewhat from the bottom of the cowl, and I think that I should cut them at an angle to create that "sucking" effect. Now for the question. Does anyone have an EDUCATED opinion on the angle, to the air stream, at which I should cut these tubes to get the maximum "suck"? See N64KR at http://KRBuilder.org - Then click on the pics See you at the 2007 - KR Gathering There is a time for building and a time for FLYING and the time for Flying has begun. Daniel R. Heath - Lexington, SC
KR> Sucking air - Oil temp problem
Before you go to all that trouble check that your gauge is accurate .Check it in oil that you heat up and use a cooking thermometer compare the two. Jim B - Original Message - From: "Dan Heath" To: Sent: Sunday, October 15, 2006 1:23 PM Subject: KR> Sucking air - Oil temp problem > Well, I originally planned to build a plenum behind the oil cooler and > duct > it to a venturi on the bottom of the cowl. Then one of guys at the > airport, > who's opinion I greatly respect, convinced me to make an "air grabber" of > sorts, and force the air into a plenum in front of the oil cooler. I > tried > every way I could and could not find enough room to put the intake hose > into > the plenum, or to route and secure the intake hose where it would get a > lot > of air. So, back to the first plan, and figure out the venturi as the > plenum was already configured. Well, that was getting very complicated as > there is not much room inside the cowling, due to the crossover exhaust. > > So, I decided to put two 2" aluminum tubes through the bottom of the cowl, > sort of like very short exhaust pipes, to which I will run my air ducts > from > the plenum, behind the oil cooler. These will protrude somewhat from the > bottom of the cowl, and I think that I should cut them at an angle to > create > that "sucking" effect. > > Now for the question. Does anyone have an EDUCATED opinion on the angle, > to > the air stream, at which I should cut these tubes to get the maximum > "suck"? > > > See N64KR at http://KRBuilder.org - Then click on the pics > See you at the 2007 - KR Gathering > There is a time for building and a time for FLYING and the time for Flying > has begun. > Daniel R. Heath - Lexington, SC > ___ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html >
KR> Sucking air - Oil temp problem
90 degrees to airflow is what I was trying to tell you. I would not protrude them, try to make them level with the cowling if you can. If you protrude them, they will create turbulance and drag. You want the air to pass over the openings of the tubes smoothly and that will create the vacumn. Larry H. from: Dan Heath Sucking air - Oil temp problem So, I decided to put two 2" aluminum tubes through the bottom of the cowl, sort of like very short exhaust pipes, to which I will run my air ducts from the plenum, behind the oil cooler. These will protrude somewhat from the bottom of the cowl, and I think that I should cut them at an angle to create that "sucking" effect. Now for the question. Does anyone have an EDUCATED opinion on the angle, to the air stream, at which I should cut these tubes to get the maximum "suck"?
