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downdraft vs updraft cooling

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Anybody notice Wayne's Zen like workspace with picture windows and garden? I half expected to see raked white sand out there and little guys in yellow robes. What an awesome environment Wayne.

...Chrisis

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Cheers Lynn. Thanks for the motivation to get this mod done.

 

I decided to feed my induction and oil cooler in a self contained system. I only have the one SW 10599R 9 row. I may need a second unit like yourself. I went with a oblique diffuser to the cooler and mounted it longitudinally. I found this in Aerodynamics of Propulsion by Kuchemann and Weber. The oil outlet is throttled with a butterfly valve on a push-pull line back to the throttle quadrant.

very well done. I have found that most of the 360s need at least a 13 row cooler on a hot day. with a very efficient cooler set up a 9 may be enough. I had a setup similar to yours and it worked in the cool weather but got over 240 in the summer at full throttle. the other problem was it did not cool on the ground during taxi until I removed the discharge plenum and the suction from the prop in the lower cowling would pull air through the cooler. now I have a 9 row on each side mounted behind small armpit scoops and dumping into the lower cowling. need to throttle one down a bit in the winter. have a good test flight

Lynn

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One advantage i can see of downdraft (being a canadian) is not picking up debris especially in the winter. Wayne, i love your plane awesome colour choice, cooling setup and workspace.

Happy flying

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very well done. I have found that most of the 360s need at least a 13 row cooler on a hot day. with a very efficient cooler set up a 9 may be enough. I had a setup similar to yours and it worked in the cool weather but got over 240 in the summer at full throttle. the other problem was it did not cool on the ground during taxi until I removed the discharge plenum and the suction from the prop in the lower cowling would pull air through the cooler. now I have a 9 row on each side mounted behind small armpit scoops and dumping into the lower cowling. need to throttle one down a bit in the winter. have a good test flight

Lynn

In my old updraft configuration, the 9 row gave me about 215F max on a high ambient temp day. That updraft system was REALLY leaky! :-) I know the RV-8 guys using the angle valve 360 are having lots of troubles with oil cooling, but the parallel valve 360 guys are having less trouble. I didn't get the test flight done last weekend due to a dead skytec starter.

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In my old updraft configuration, the 9 row gave me about 215F max on a high ambient temp day. That updraft system was REALLY leaky! :-) I know the RV-8 guys using the angle valve 360 are having lots of troubles with oil cooling, but the parallel valve 360 guys are having less trouble. I didn't get the test flight done last weekend due to a dead skytec starter.

I have heard this too. the deeper oil pan on the straight valve may have something to do with it. I do know if you have the cam spray nozzles installed it will heat the oil up more. so another dead skytec starter. was it new. seems one out of two new skytecs are defective right out of the box. if you get a good one they are great but I have seen many bad ones. even had a new one the was not machined right and there was no backlass between the gears and it only lasted three starts.

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I have heard this too. the deeper oil pan on the straight valve may have something to do with it. I do know if you have the cam spray nozzles installed it will heat the oil up more. so another dead skytec starter. was it new. seems one out of two new skytecs are defective right out of the box. if you get a good one they are great but I have seen many bad ones. even had a new one the was not machined right and there was no backlass between the gears and it only lasted three starts.

 

The starter has been on the aircraft since first flight. It has always struggled. I read James Redmon's upgrade to the B&C on www.berkut13.com and have bitten the bullet. The B&C arrives on Friday. B&C caught wind of my problems with the skytec and actually sent me a starter to try when I was living in Seattle. I should have swapped it then, but I didn't want to rip into my new baffling. With the baffling now gone, it's bye bye skytec. Good customer service goes a long way - eg Aero Sport Power Kamloops BC has the finest customer service I have dealt with BTW. Just superb.

 

I think if I have a problem with oil cooling, it may be the way I'm diffusing the air, so I have a backup plan. If that doesn't work, I'll try to get more air into the inlet with VGs. If that doesn't work, I'll go to a 13row, or a second cooler off the back of one of the plenums. I nearly added coolers behind each plenum and treated the plenum design like I had 6 cylinders. I would have throttled the oil cooler outlets on both cooler undersides to make the system work. That may happen next. I also may take plenum air from between the cylinders each side and use that to aid air extraction out the back of the cooler, or to introduce more air mass into the coolers oblique diffuser. It's all about mass flow and pressure drop.

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About Updraft Cooling ... good! :)

 

In order to build some time and get more comfortable on the plane, I did a X-country of about 97 Nm,

On the way back it was just starting to get bumpy (28 C up there) and it flew just as nice, however, I did notice the performance slacking off some 15Nm to BaraG (FASY), no amount of leaning or fiddling could get it back, and it was not the wind ...

 

Anyway, came in a little fast to 31 at the drome and decided on a go around.

 

Soon as I took power the whole contraption started spluttering and coughing, so I did a shortish tight circle and put her down, what a snap, crackle and pop to get the show to the hangar (slight uphill)

 

On shutdown, I saw lots of oil on the prop and all over. Totally peeved, made it secure and left for home, not wanting to deal with any more problems on that day.

 

Sunday - pulled the cowlings and was surprised to find the # 02 spark upper plug lead had separated and was loosely in place - must have been an oversight in my checking, since I cannot believe that this can come adrift by itself.

 

Much more interesting was that the # 03 fuel injector pipe had broken and was held together by the rubber insulation, not quite right off, but a light jiggle and it came apart smartly!

 

The underside of the top cowl was blue from the fuel dye and must have had copious quantity of fuel go over this.

The updraft cooling must have saved the day, since it appears to have blown the fuel vapours right out, what with the opposite side having a sparking wire at the ready to create havoc.

 

Must have been my lucky day, what with not catching fire & such ... :-) But that is mostly due to the Updraft cooling!

 

Regards

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About Skytec ...

 

The slightest kickback will kill the lightweigt Skytec.

 

I've even managed to destroy the larger type, that too with a kickback.

 

Then I changed from the "shower of sparks / starter vibrator" set-up to straight impluse magnetos and that was the end of my problem with starters ...

 

Hope this has some value to the reader :)

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First downdraft flight was a success.

 

I cruise climbed to 3000ft DA and set 2300RPM and watched #1, #2, & #3 CHTs drop slowly into the 360s. #4 stayed at 390 and oil = 180F. At 2500RPM, CHTs #1, #2, #3 stabilized around 350-370F, #4 was 405F (needs assessment), oil topped out at 185F. Oil never went above 190F even in climb which was a HUGE surprise. OAT was 75F or so.

 

It's going faster. I'll get solid data this weekend.

 

All this with a pumped up O-360 and the same size inlets as Bill James O-235 (5" x 1.5").........

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HI there,

 

Installed the B&C starter. Without changing anything else the prop roared around. Problem solved. Nothing wrong with the Skytec, it's just higher torque at higher current and struggles with the setup.

 

Have flown one flight since. All CHTs 390F, Oil topped out at 180F. OAT was 73F. I need to get slightly better airflow through the NACA inlets for cylinders. They are dedicated 5" x 1.5455" inlets through dedicated diffusers and dual plenums. I'll increase flow with some tiny 1/4" VGs. I need to add some piccolo tubes in and under the plenums and get some solid pressure data with and without VGs. Topped out at 190KIAS at 4000ft with the Hertzler Mk IV cozy prop. This reflected the first flight.

 

I've refinished the Lightspeed Berkut prop and have had it painted. I need to balance it and check top end. It used to give me 206KTAS, but I expect to get approx 215KTAS now. The new Hetzler prop probably isn't far off either with more pitch which should be a match for the lightspeed top end and have much better takeoff performance.

 

I removed cowls and all is well. The plenums seal against the crankcase cylinder flanges which I thought might me a problem. None observed. Tg not an issue without load.

 

I see no difference in MAP from the previous config. The old Berkut centreline inlet spilled a lot of air. I am staggered the new little 5" wide centerlne flush inlet diffused once for induction with spilled air diffused a second time for oil is working so well to provide induction and oil air. I'll take measurements in time, but I'm getting textbook performance in line with calculations. I think I can do even better. The throttle oil outlet works well in controlling airflow, and has a direct affect on MAP when closing.

 

Re-routing of the rudder cable conduits has put my rudders about 1/4" to 3/8" actuated at the tops. I can see them still delfected against the fixed upper winglet portion when I'm flying. Have to fix that. For anyone who is cutting your rudders full length, like I've always said, good luck seeing an in trail position from the cockpit! Not a good idea.

 

I'm done with mods for a while! My recommendation to all building is just get it finished and go fly! Having my plane out of the air was awful. Now that it is going, I haven't had much time to fly, but it's there when I want to and that is COOL.

 

Cheers

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HI there, Installed the B&C starter. Without changing anything else the prop roared around. Problem solved. Nothing wrong with the Skytec, it's just higher torque at higher current and struggles with the setup. Have flown one flight since. All CHTs 390F, Oil topped out at 180F. OAT was 73F. I need to get slightly better airflow through the NACA inlets for cylinders. They are dedicated 5" x 1.5455" inlets through dedicated diffusers and dual plenums. I'll increase flow with some tiny 1/4" VGs. I need to add some piccolo tubes in and under the plenums and get some solid pressure data with and without VGs. Topped out at 190KIAS at 4000ft with the Hertzler Mk IV cozy prop. This reflected the first flight. I've refinished the Lightspeed Berkut prop and have had it painted. I need to balance it and check top end. It used to give me 206KTAS, but I expect to get approx 215KTAS now. The new Hetzler prop probably isn't far off either with more pitch which should be a match for the lightspeed top end and have much better takeoff performance. I removed cowls and all is well. The plenums seal against the crankcase cylinder flanges which I thought might me a problem. None observed. Tg not an issue without load. I see no difference in MAP from the previous config. The old Berkut centreline inlet spilled a lot of air. I am staggered the new little 5" wide centerlne flush inlet diffused once for induction with spilled air diffused a second time for oil is working so well to provide induction and oil air. I'll take measurements in time, but I'm getting textbook performance in line with calculations. I think I can do even better. The throttle oil outlet works well in controlling airflow, and has a direct affect on MAP when closing. Re-routing of the rudder cable conduits has put my rudders about 1/4" to 3/8" actuated at the tops. I can see them still delfected against the fixed upper winglet portion when I'm flying. Have to fix that. For anyone who is cutting your rudders full length, like I've always said, good luck seeing an in trail position from the cockpit! Not a good idea. I'm done with mods for a while! My recommendation to all building is just get it finished and go fly! Having my plane out of the air was awful. Now that it is going, I haven't had much time to fly, but it's there when I want to and that is COOL. Cheers

Hi Wayne, How did your downdraft turn out? Are you selling kits? I'm looking for downdraft for an IO-360 installation. Thanks, Brian

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