That is an interesting test that You made... Heat exchange whether it be air flowing over a cooler, over a set of cooling fins, over an oil sump or even a heat muff, all need air flow to carry away the heat... The best way to achieve air flow is to positively move the ambient cooler air over the hot areas, and then move that air downward. The engine heat will then be carried away, as it will move in the direction of the airflow... Many engine bays are set-up to move the heated air downward, so as to take advantage of the cooler, denser (heavier) air having a natural tendency to move downward and using the forced air coming from the propeller cuffs, and through the cooling inlets at the front of the cowls. Another thing that enhances heat exchange, is shrouding the surrounding horizontal plane of the cylinders, to isolate the higher pressure cool air on top of the cowling, from the heated air being forced downward, and outside of the exits at the lower aft end of the lower cowl half...Something that could improve the engine cooling on your plane, is to seal-off that slotted hole and use the NACA duct to supply ram air to the induction system using some scat tubing, as it was originally intended to do.. The higher pressure ALWAYS needs to be in the isolated upper half of the cowling, and the lower pressure needs to be at the lower end of the cowling.... Pressurizing the lower cowling will slow the airflow btwn the upper & lower cowling halves and reduce the heat exchange capabilities.... If you want maximum benefit from your engine oil cooler, locate it in such a way that the higher pressure (cool) air from the upper cowl area, blows through it to carry the heat away towards the lower pressure cowl on the lower half of the engine bay...So one side of the oil cooler should be exposed to the hi-pressure (cool) inlet engine cooling air , while the other side of the oil cooler is exposed to, or plumbed to with an exit shroud & scat tubing, to the low pressure & heated air side of the lower eng. cowl...More really nice tricks are available when applying thermal-dynamics... Look into the use of exhaust system augmentors... These help to carry away heat, give a negative pressure on the exhaust system exits - increasing engine performance, and provide a slight forward 'push' to help propel the plane, and costing relatively little $ to fabricate... Several of the NAA Navion planes were fitted with exhaust augmentors....Other planes were seen with them too, especially the ones that operated in high temperatures....
Well observed and well executed. I, too, fly a plane that is riding the knifes edge in terms of engine temperatures. From experience I can recommend that you keep and improve that "smiley" air intake. You should modify it to have a generously rounded edge with a nozzle style air funnel and, if possible, expansion path inwardly, pointing the air directly at the oil sump. Research the front air intake of the old Jaguar D-Type - that is exactly what you'll want to emulate. It will provide good cooling performance at high speeds, reduced airflow at low speeds, all at a minimized size of the intake. NACA intakes are meant to be installed in areas that are parallel to the airflow, but in the almost vertical part of the front mask they just don't work.
when something like this happens in RC airplanes we increase the exit air volicity by putting a airdamn on the bottom of the cowl to creat low pesure under the cowl thus increasting the air out the rule of thump is for 1x for sql area 3x sql area for exhuast
The bottom air intake could be used as a ram air source for the carb. If it only allows air into the carb and not into the bottom of the cowling this should provide the proper pressure differential and also the higher engine rpm’s.
I definitely had that thought. My only reservation is the aerocarb manual specifically says not to use a sealed ram air source. I think the concern is the increasing requirement for fuel with increasing speed so that you would need to ENRICH the mixture as you went faster. It could be difficult to find the right needle/carb adjustment to make to work well.
@@LeanofPeakAviation If you pump significant ram air pressure into the venturi, you will get reduced fuel flow out of the fuel jet coming from the float bowl into the venturi. This is because the reason the fuel flows from the float bowl into the venturi is because the air pressure in the venturi is lower than the air pressure in the float bowl (venturi effect). If you were able to keep the entire carburetor (or at least the venturi intake and float bowl vent lines) at the same ram air pressure, it should work fine with increased ram pressure. Increased air pressure should be no problem, as long as the entire carburetor gets to experience this pressure increase. I think.
@@sganzerlag So the aerocarb/aero injector is different than a traditional carburetor in that there is no venturi or float bowl. It’s a throttle body injector as Sonex describes it. They are extremely simple devices that don’t require carb heat and operate reliably on gravity feed. According to their manual increasing ram pressure will necessitate increased fuel delivery and you’ll be making the fuel more rich as you go faster.
@@LeanofPeakAviation dude my bad! Sorry about the confusion. I get it now, it's similar to the Ellison TBI. How are you liking the Aerocarb TBI? Was it relatively simple to setup and tune?? I love simplicity and those TBIs seem to be as simple as it gets.
Great videos. I run a VW based engine on my kitfox and have ran through some of the same troubleshooting. I’m now considering another prop pitch for higher RPM gain. What’s the prop length and pitch on the Onex?
How about air exits on the side of the cowling like the new B models? May possibly just not have enough exit area with all of the intake area you now have. The side exit is in a lower pressure zone than the bottom as well.
Baffling as in adding baffling. I am not familiar with your under cowling but I know there are plenty of smart guys out there who can figure this out. On another subject, a friend I used to fly with had a Mooney Mite and that setup worked fine Jugs hanging out in the wind. Both yours and the Mite are great little aircraft!
Here’s my two cents… if you have lots of free time and just really want to build one it can be a rewarding experience and you’ll get exactly what you want. That being said you’ll spend far more money building one than buying second hand. Most people are going to spend $40,000 or more building one of these. You can get one gently used all day long for $25,000. The reality is most projects don’t ever get finished because people get frustrated or bored and quit. Sonex makes a really great kit, so if building is your thing then go for it. If you just want to fly… find a nice used one, get a pre-purchase inspection from a third party A+P, and get flying. Hope that helps!
![FNAF Into the Pit has A LOT of Unused Graphics | LOST BITS [TetraBitGaming]](http://i.ytimg.com/vi/6YhZCRdipl4/mqdefault.jpg)
As others have said... install a reverse scoop to bottom of the cowl. It will put a vacuum in the cowl and will scavenge the hot air more efficiently.
That is an interesting test that You made... Heat exchange whether it be air flowing over a cooler, over a set of cooling fins, over an oil sump or even a heat muff, all need air flow to carry away the heat... The best way to achieve air flow is to positively move the ambient cooler air over the hot areas, and then move that air downward. The engine heat will then be carried away, as it will move in the direction of the airflow... Many engine bays are set-up to move the heated air downward, so as to take advantage of the cooler, denser (heavier) air having a natural tendency to move downward and using the forced air coming from the propeller cuffs, and through the cooling inlets at the front of the cowls. Another thing that enhances heat exchange, is shrouding the surrounding horizontal plane of the cylinders, to isolate the higher pressure cool air on top of the cowling, from the heated air being forced downward, and outside of the exits at the lower aft end of the lower cowl half...Something that could improve the engine cooling on your plane, is to seal-off that slotted hole and use the NACA duct to supply ram air to the induction system using some scat tubing, as it was originally intended to do.. The higher pressure ALWAYS needs to be in the isolated upper half of the cowling, and the lower pressure needs to be at the lower end of the cowling.... Pressurizing the lower cowling will slow the airflow btwn the upper & lower cowling halves and reduce the heat exchange capabilities.... If you want maximum benefit from your engine oil cooler, locate it in such a way that the higher pressure (cool) air from the upper cowl area, blows through it to carry the heat away towards the lower pressure cowl on the lower half of the engine bay...So one side of the oil cooler should be exposed to the hi-pressure (cool) inlet engine cooling air , while the other side of the oil cooler is exposed to, or plumbed to with an exit shroud & scat tubing, to the low pressure & heated air side of the lower eng. cowl...More really nice tricks are available when applying thermal-dynamics... Look into the use of exhaust system augmentors... These help to carry away heat, give a negative pressure on the exhaust system exits - increasing engine performance, and provide a slight forward 'push' to help propel the plane, and costing relatively little $ to fabricate... Several of the NAA Navion planes were fitted with exhaust augmentors....Other planes were seen with them too, especially the ones that operated in high temperatures....
Excellent post. Thank you.
@@LeanofPeakAviation Thank you... Something that I remember from my A&P class days...Back in the early 80's.... Fly safe Amigo!!!
Laughing hysterically at the squeaky toy in a rather technical video 😂👍🛫 - Jacob
Lol. I’ve got an Aussie dog that hangs out with me at the airport. Poor guy I had to steal his ball!
Well observed and well executed.
I, too, fly a plane that is riding the knifes edge in terms of engine temperatures. From experience I can recommend that you keep and improve that "smiley" air intake. You should modify it to have a generously rounded edge with a nozzle style air funnel and, if possible, expansion path inwardly, pointing the air directly at the oil sump.
Research the front air intake of the old Jaguar D-Type - that is exactly what you'll want to emulate.
It will provide good cooling performance at high speeds, reduced airflow at low speeds, all at a minimized size of the intake.
NACA intakes are meant to be installed in areas that are parallel to the airflow, but in the almost vertical part of the front mask they just don't work.
Thanks for the advice!
when something like this happens in RC airplanes we increase the exit air volicity by putting a airdamn on the bottom of the cowl to creat low pesure under the cowl thus increasting the air out the rule of thump is for 1x for sql area 3x sql area for exhuast
The bottom air intake could be used as a ram air source for the carb. If it only allows air into the carb and not into the bottom of the cowling this should provide the proper pressure differential and also the higher engine rpm’s.
I definitely had that thought. My only reservation is the aerocarb manual specifically says not to use a sealed ram air source. I think the concern is the increasing requirement for fuel with increasing speed so that you would need to ENRICH the mixture as you went faster. It could be difficult to find the right needle/carb adjustment to make to work well.
@@LeanofPeakAviation If you pump significant ram air pressure into the venturi, you will get reduced fuel flow out of the fuel jet coming from the float bowl into the venturi. This is because the reason the fuel flows from the float bowl into the venturi is because the air pressure in the venturi is lower than the air pressure in the float bowl (venturi effect). If you were able to keep the entire carburetor (or at least the venturi intake and float bowl vent lines) at the same ram air pressure, it should work fine with increased ram pressure. Increased air pressure should be no problem, as long as the entire carburetor gets to experience this pressure increase. I think.
@@sganzerlag So the aerocarb/aero injector is different than a traditional carburetor in that there is no venturi or float bowl. It’s a throttle body injector as Sonex describes it. They are extremely simple devices that don’t require carb heat and operate reliably on gravity feed. According to their manual increasing ram pressure will necessitate increased fuel delivery and you’ll be making the fuel more rich as you go faster.
@@LeanofPeakAviation dude my bad! Sorry about the confusion. I get it now, it's similar to the Ellison TBI. How are you liking the Aerocarb TBI? Was it relatively simple to setup and tune?? I love simplicity and those TBIs seem to be as simple as it gets.
@@sganzerlag I think they work great. Very easy to tune and not worrying about carb heat is a big plus. Simple as it gets.
Great videos. I run a VW based engine on my kitfox and have ran through some of the same troubleshooting. I’m now considering another prop pitch for higher RPM gain. What’s the prop length and pitch on the Onex?
How about air exits on the side of the cowling like the new B models?
May possibly just not have enough exit area with all of the intake area you now have.
The side exit is in a lower pressure zone than the bottom as well.
I do like the side vents in the B model.
Baffling as in adding baffling. I am not familiar with your under cowling but I know there are plenty of smart guys out there who can figure this out. On another subject, a friend I used to fly with had a Mooney Mite and that setup worked fine Jugs hanging out in the wind. Both yours and the Mite are great little aircraft!
In process of wanting one but don’t know whether buy it or build it…any help, thanks
Here’s my two cents… if you have lots of free time and just really want to build one it can be a rewarding experience and you’ll get exactly what you want. That being said you’ll spend far more money building one than buying second hand. Most people are going to spend $40,000 or more building one of these. You can get one gently used all day long for $25,000. The reality is most projects don’t ever get finished because people get frustrated or bored and quit. Sonex makes a really great kit, so if building is your thing then go for it. If you just want to fly… find a nice used one, get a pre-purchase inspection from a third party A+P, and get flying. Hope that helps!
good to know
I believe that is a Revmaster engine……
It’s an Aerovee
The gold paint on the case is throwing you for a loop as that's what Revmaster uses. You can confirm that it's an Aerovee in his other vids though. 😉
Do you have a top mounted oil cooler on your Aerovee?
Yep.