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Louvers

tclaire

Active Member
When installing louvers on the cowl do most install them on the bottom of the cowl or on the side of the cowl, is there any advantage in either place
Tim
 
When installing louvers on the cowl do most install them on the bottom of the cowl or on the side of the cowl, is there any advantage in either place
Tim

May I ask why you are installing louvers ? do you have temp problems ?
 
May I ask why you are installing louvers ? do you have temp problems ?

we have been fighting oil temps when the out side temp starting creeping up
in the 80s, we have sealed all bafflings, change to a larger oil cooler fire wall mounted, up at altitude at cruise the temps stay in line, but down low with warm temps and slower speeds oil temps go up, cyclinder temps are alway good up high or down low 310 to 350.. after looking into we installed the vetterman exhaust with mufflers and looking into the cowl the mufflers are pretty large and block the air flow from the oil cooler to the exit of the cowl.
with the louvers hope to have a air flow for the oil cooler ( I hope)

Tim
 
Is this a new or overhauled engine? The reason I ask is that an IA friend of mine chased high oil temps on a low time overhauled Lycoming, installed on a RV-6, for two months doing everything possible to provide more air flow through the cooler. Finally, he discovered that the vernatherm was not seating completely and routing the oil to the cooler. He also found that not all vernatherms are created equal, they all seem to expand to different lengths at 200F (boiling water, thermometer, and caliper). He ordered 4 new units and installed the one with the longest expansion (that exceeded the original) and returned the other 3, problem solved. I hope this might be of help. Dan
 
I am chasing the same problem on a 6A with a factory O-360-A1A. I see 160's in the winter, and 230 in the summer. I am upgradiing the cooler from a 7 row to a 13 row. Louvers, exit ramps, ect. seem to require a lot of work, and only a hope of success; but I might be right behind you if the larger cooler does not work. - What coolers have you tried? I have a Positech P20002C and am going to an Airflow Systems 2006X. I hope to have the new cooler on by next weekend, so will tell you how I make out.
 
My oil is at 174 - 184 F all year with the std oil cooler vans send with the kit.
I was looking at louvers for cooling cht #3.
I look forward to what you find. Good luck !
 
Is this a new or overhauled engine? The reason I ask is that an IA friend of mine chased high oil temps on a low time overhauled Lycoming, installed on a RV-6, for two months doing everything possible to provide more air flow through the cooler. Finally, he discovered that the vernatherm was not seating completely and routing the oil to the cooler. He also found that not all vernatherms are created equal, they all seem to expand to different lengths at 200F (boiling water, thermometer, and caliper). He ordered 4 new units and installed the one with the longest expansion (that exceeded the original) and returned the other 3, problem solved. I hope this might be of help. Dan
we changed the oil filter housing as we could see the vernatherm was not setting with a full ring around the seat, we changed the vernatherm at the time also it help a little but at lower alt and slower air speed the oil temps rise 220 to 230 at higher alt and full air speed the temps stay 185 hope the louvers help, i will keep you posted
Tim
 
I spoke with Bill from Airflow Solutions today. He recomends that they be put on the side of the cowl. The reason is that the bottom of an RV cowl becomes a high pressure area during climb. He said that the sides are always low pressure.
 
When did you get the Louvers from ? Does Vans sell them ?
So I can put them on the side OR the bottom. I think the bottom would look better as my cowls are already painted.
 
A.S.A. Temp. Control !!!!

...If you guys with heat issues on climb-out can wait about a month, we will be in production of another product that will solve this issue. It won't be ugly, it will install very easily, won't require re-painting, won't bankrupt your budget and best of all, will not slow your airplane down. We have seen louvers really have a dramatic detrimental effect on speed as the exit air velocity is reduced, causing considerable drag. Our new product (currently in end stage testing) will not do this so you get the best of both worlds. We are seeing on long, hard climbs, cyl. temp reductions of 40 to 60 degrees and oil temps reduced 25 to 35 degrees. We have been working on and improving this product for almost a year and are now tooling it for production. If you can wait just a little longer, you won't be disappointed. Thanks, Allan... :D
 
Allan, what models of RV is your new product designed to fit??

Hi! Mike
....This will work on all RV models and many others in the experimental, light sport and home built categories.
This problem is one that seem to pop up quite often, so we took it on and a very nice product has emerged. I am certain most all will like this one.
....We are in process on the RV-10 "Ultimate Gust Lock"! Hint Hint. Thanks, Allan.. :D
 
I put mine on the bottom and I saw lower chts and oil temp. Around 10 deg on the oil and 20 deg on my highest chts. I have a 4 pipe exhaust and I needed more room for air to exit. This seemed to help me. Good luck !
 
...If you guys with heat issues on climb-out can wait about a month, we will be in production of another product that will solve this issue. It won't be ugly, it will install very easily, won't require re-painting, won't bankrupt your budget and best of all, will not slow your airplane down. We have seen louvers really have a dramatic detrimental effect on speed as the exit air velocity is reduced, causing considerable drag. Our new product (currently in end stage testing) will not do this so you get the best of both worlds. We are seeing on long, hard climbs, cyl. temp reductions of 40 to 60 degrees and oil temps reduced 25 to 35 degrees. We have been working on and improving this product for almost a year and are now tooling it for production. If you can wait just a little longer, you won't be disappointed. Thanks, Allan... :D

Any update on this???
 
we have been fighting oil temps when the out side temp starting creeping up
in the 80s, we have sealed all bafflings, change to a larger oil cooler fire wall mounted, up at altitude at cruise the temps stay in line, but down low with warm temps and slower speeds oil temps go up, cyclinder temps are alway good up high or down low 310 to 350.. after looking into we installed the vetterman exhaust with mufflers and looking into the cowl the mufflers are pretty large and block the air flow from the oil cooler to the exit of the cowl.
with the louvers hope to have a air flow for the oil cooler ( I hope)

Tim
Installed the louvers on the bottom of the cowl it lowered the oil temps and cyclinder temps, I also disconnected the map line going to the p-mags to keep them advancing the timing at lower manifold pressure, I have only done a couple a flights with these changes the oil temps are staying around 180 to 195 so far so good,
Tim
 
Tim,

I am glad you posted that....and I like what I see. I see too much advance being a problem for a lot of people, and no HP gain. It does help when LOP, but none of the EI's on the market get my mouth watering. So how much did this help? I assume you plugged the lead from the head?

Louvres on the sides should work even better. Think about the Thorpe cowls. Liquidaire Baffles........ they work for a reason. Areas of negative pressure.
 
Tim,

I am glad you posted that....and I like what I see. I see too much advance being a problem for a lot of people, and no HP gain. It does help when LOP, but none of the EI's on the market get my mouth watering. So how much did this help? I assume you plugged the lead from the head?

Louvres on the sides should work even better. Think about the Thorpe cowls. Liquidaire Baffles........ they work for a reason. Areas of negative pressure.
Over all the the oil temps dropped around 20-25 degrees i never really had a problem at cruise and the throttle wide open.. on the map i just capped off the map line and on the p-mag left the map dissconnected so when i reduce the throttle it does not advance the timing it stays set. I have a sneaky feeling this was my heat problem all along, it was advancing the ignition and heating things up when reducing the throttle
 
I droped my oil temp 45 degrees by replacing my Positech 6 row with an Airflow Systems 13 row and re-working the infeed plenum behind my NACA duct.
 
DROP IN SPEED ??

...If you guys with heat issues on climb-out can wait about a month, we will be in production of another product that will solve this issue. It won't be ugly, it will install very easily, won't require re-painting, won't bankrupt your budget and best of all, will not slow your airplane down. We have seen louvers really have a dramatic detrimental effect on speed as the exit air velocity is reduced, causing considerable drag. Our new product (currently in end stage testing) will not do this so you get the best of both worlds. We are seeing on long, hard climbs, cyl. temp reductions of 40 to 60 degrees and oil temps reduced 25 to 35 degrees. We have been working on and improving this product for almost a year and are now tooling it for production. If you can wait just a little longer, you won't be disappointed. Thanks, Allan... :D

Out of at least 100 sets of louvers that we have sold, I have not heard one customer say that they lost speed. And $20 bucks per louver does not sound that expensive to me. I'm just saying....

Alex D
 
Out of at least 100 sets of louvers that we have sold, I have not heard one customer say that they lost speed.

From Raymer, Dc = M (Vi - Vo)...cooling drag is mass x velocity loss, freestream (Vi) less outlet velocity (Vo).
 
IMG_1938.JPG


Speed loss or not they work.
Even on really hot days around here <100> F, I never see Cylinder head temps get above 380F and drop around 320 immediately after leveling off.
Oil temps stay below 200F for climb and 180 for cruise on hot days.
On most days during the colder month I close the butterfly valve to keep oil temps up.
 
From Raymer, Dc = M (Vi - Vo)...cooling drag is mass x velocity loss, freestream (Vi) less outlet velocity (Vo).

Despite the cool calculation formula, any loss in speed from the louvers likely would not be measurable by any equipment any of us could afford.:rolleyes:
 
Louvers absolutely work, assuming temperature reduction is the single criteria. Nothing sinful about that if it is what you want.

The equation is merely a statement of relationships which vary for no one. Louvers cannot suspend reality.

Pilots flying any GA airplane with exit area variable in flight will attest to an immediate gross airspeed response. In my own case an inflight area reduction of roughly 1/3 is good for 3-4 knots. True, the EFIS is an exotic and expensive instrument, but I had one handy....;)
 
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"assuming temperature reduction is the single criteria"--seems that was exactly what the original poster wanted to achieve. He found a solution--maybe not everyones--but simple, proven, and easy to implement!

Cheers,

db
 
Speed measurements of two or three 3 knots is anecdotal at best with the average pitot/static system available to GA airplanes. Even the various patterns flown with the GPS is at best, a SWAG!

:DBut it does make us feel better:D

Cheers
 
speed

Thinking of installing louvers for oil cooler high temps what difference does it make if the cooling air is coming out of the big hole in center of the bottom of the cowling or little holes in the bottom if the volume is the same as far as drag?
Thanks Bob
 
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