[Desert Rat]

I'm installing an IO-390 in my RV 7 and am currently working on the baffles.

I was planning to do the Airflow Systems duct with the butterfly flapper and control it via a cable in the cabin, as I've seen other folks do.

However, looking at this, that flange is about twice as long as the simple Vans flange which came in some kit or another.

Also, I'm not thrilled with the lever arm arrangement on the Airflow unit. The shaft isn't splined, so if the set screw comes loose the butterfly will be free to do it's own thing including potentially closing off the airflow to the cooler.

For those of you who have this arrangement, do you really use the flapper to manage airflow, or is it one of those things that you installed but find that you rarely use?

I guess another way to ask the same question would be; since there isn't any provision for airflow control in the similar setup on the RV14, do people with those planes typically have any issue with low oil temp in winter operations?

I'm including a couple of pix of option A and option B in case this isn't clear.

 

[Richard Connell]

I had a larger oil cooler in my IO360 RV7 as I fly in a hot climate at times.
No butterfly. Never had any issues. It dosent get cool enough here to really ever worry about blanking it in winter.
For my -10 I also went with 1 size bigger cooler plus a butterfly as I am running 9:1.
In practise: I’ve never touched the butterfly, temps are fine all year round once I’m airborne but I’ll sometimes see 210+ on hot day turnarounds.
The linear actuator failed anyway (open thankfully) at maybe 50h so it’ll get removed probably at next annual.

In short it was a waste of time- with the potential to be an actual problem. I wouldn’t do it again.
So if I was in your place I’d just put an appropriate sized bigger cooler in and in the unlikely scenario in which you are too cool in winter, fit a (small) blanking plate.
Cheers

 

[Freemasm]

Butterfly valves have very low losses when fully open but flat-out suck for flow control. The flow characteristic doesn't get serious until it's mostly closed and then it is very touchy.

As already mentioned, it's probably not needed. If low oil tmeps become a problem, the ASA louvered control would be an easy retrofit.

Best of luck

 

[lr172]

The need for an cooler door is related to your need to precisely control something that doesn't need to be precisely controlled. Some folks just feel that the oil temp should be 180 +/- 5* and feel compelled to do whatever it takes to keep the oil there. The rest of us just take what we get and worry about it only if it gets outside the limits (160-235 summer / 140-235 winter), which is Lyc's guidance BTW. I have almost 1000 hours on my 6A and it has not let me down yet. I often just barely get to 160 in the winter months, sometimes it is 150. Engine hasn't failed me yet and feel no need for a shutter to bring it up. For the record, I care about my engine and do many things outside the norm to insure that it provides long life. Just do not feel that keeping temps above 150 is required.

You have already found a serious risk (arm slipping) that could cause serious problems (over heating) and unless you are the OCD type, with no real offsetting benefit. Modifications like this really should involve a risk/benefit analysis. And I get it for some of the guys. If the numbers don't match what Mike Bush said they should be, they can get distracted and that can be a real risk. I recognize that we are all different and have different approaches with different priorities; No judgement being applied here.

Larry

 

[rocketman1988]

Valve

I can tell you I use my butterfly valve all the time, especially in the winter but I am running an Io540 with 9:1 and CAI. It works great, and unlike a previous post, is quite precise. In the summer, it is wide open for takeoff and climb an closed down while cruising at around 10k…

 

[DanH]

Let's not confuse parallel valve requirements with angle valve cooling.

In general, big picture...

parallel valve = higher CHT, lower oil temperature
angle valve = lower CHT, higher oil temperature

Returning to Terry's question, there are several variables, notably oil cooler size. Personally, I'd do the install without the butterfly, fly one annual cycle, then mod as desired.

 

[dmattmul]

Butterfly Valve

I use it on the ground to help warm up the oil quicker. In flight it's almost always wide open. For a 390-angle valve it's more of a "convenience" if anything. On a parallel valve engine probably a good thing to have.

 

[Freemasm]

I can tell you I use my butterfly valve all the time, especially in the winter but I am running an Io540 with 9:1 and CAI. It works great, and unlike a previous post, is quite precise. In the summer, it is wide open for takeoff and climb an closed down while cruising at around 10k…

Standing by my statement and have a lot of fluid systems design experience to back it up. Butterfly valves suck at flow control. They have low losses when open. They are relatively cheap. Their flow control (as a function of position) is the worst. Here, they take up a lot of room. In general, if you have to control both process fluids, something probably isn't sized correctly.

If you think you need airflow control, I'd consider something else. As mentioned, the ASA device is easily retrofittable. The OP has already stated a potential application/risk issue with the supplied valve. My $0.02

 

[BillL]

Standing by my statement and have a lot of fluid systems design experience to back it up. Butterfly valves suck at flow control. They have low losses when open. They are relatively cheap. Their flow control (as a function of position) is the worst. Here, they take up a lot of room. In general, if you have to control both process fluids, something probably isn't sized correctly.

If you think you need airflow control, I'd consider something else. As mentioned, the ASA device is easily retrofittable. The OP has already stated a potential application/risk issue with the supplied valve. My $0.02

I would agree in general, but these valves meet the overall needs for function, space, control precision, and cost for this particular application. As Dan pointed out, for a parallel valve use the sealing would need to be on the better side.

BTW Dan does not have a cabin heater. He goes so fast I think compression heating may make up for that.

 

[Freemasm]

Hey Bill.

In case you haven't seen this product:

https://antisplataero.com/products/oil-cooler-air-shutter

I haven't tested it but they claim it passes more air than the cooler proper. The company/their products have a good reputation. It will be my contingency application (easily retrofittable) if I need such control.

BTW, guessing the inclusion of the valve was the supplier's fudge factor/accommodation for various cooler types and associated cooling flows

As for the min. oil temp thread, are the engine OEMs afraid of lack of lube in the small passages or oil whip? Is this legacy "knowledge" related to straight weight oils/do the OEMs mention different rqmnts for multi-vis? Let us know if you know. Thx

 

[Carl Froehlich]

For all four builds the oil cooler is on the firewall. The oil cooler plenum has either a 3” (RV-8) or 4” (RV-10) butterfly valve and it is used every flight. While the need for controlling air to the cooler can be debated, I consider this an inexpensive and simple add.

I fly year round and at oxygen levels when cross country. It can get real cold out there…..

Carl

 

[rocketman1988]

Standing by my statement and have a lot of fluid systems design experience to back it up. Butterfly valves suck at flow control. They have low losses when open. They are relatively cheap. Their flow control (as a function of position) is the worst. Here, they take up a lot of room. In general, if you have to control both process fluids, something probably isn't sized correctly.

If you think you need airflow control, I'd consider something else. As mentioned, the ASA device is easily retrofittable. The OP has already stated a potential application/risk issue with the supplied valve. My $0.02

We can agree to disagree.

My -10 has been flying for more than two years, and the valve works just fine. Without the valve, at cruise altitudes, the oil temp gets too cool. In the summer heat with the valve open, I haven’t seen above 220 in an extended WOT climb. As far as control, I have no issues maintaining the recommended 190 degree temp.

Works for me, and was an easy add.

 

[Strikhedonia]

I too use the butterfly valve on my RV-10 nearly every flight (while up high) and find the temperature control to work very well. It is especially helpful in the winter to quickly heat up the oil and burn off any moisture in the crankcase.

 

[Freemasm]

For all four builds the oil cooler is on the firewall. The oil cooler plenum has either a 3” (RV-8) or 4” (RV-10) butterfly valve and it is used every flight. While the need for controlling air to the cooler can be debated, I consider this an inexpensive and simple add.

I fly year round and at oxygen levels when cross country. It can get real cold out there…..

Carl

Awesome. CF relied and can text me later telling me what a big hole I am. Think of this as control loops. You don't set up systems with two controllers/loops fighting each other. Here, the vernatherm and any airflow control are doing similar though much more slowly. With the inclusion (popular word these days) of enhanced monitoring thru advanced avionics, there's little risk of incorporating airflow control in this system. This assumes associated alarms are set up appropriately. In an analog environment, I'd say the risks of manual airflow control are greater than any potential reward.

 

[wirejock]

Butterfly

I made one. Probably not the right way but I couldn't get everything to fit any other way.
It's a 4" flange with a home made butterfly. The butterfly rotates inside the flange so it clears the hole in the baffle and the SCAT. The hole for the 4-40 screw goes through the shaft and has a lock nut.

 

[rocketman1988]

Awesome. CF relied and can text me later telling me what a big hole I am. Think of this as control loops. You don't set up systems with two controllers/loops fighting each other. Here, the vernatherm and any airflow control are doing similar though much more slowly. With the inclusion (popular word these days) of enhanced monitoring thru advanced avionics, there's little risk of incorporating airflow control in this system. This assumes associated alarms are set up appropriately. In an analog environment, I'd say the risks of manual airflow control are greater than any potential reward.

…and you are entitled to your opinion, just like everyone else. That doesn’t make other opinions any more or less valid.

 

[Strikhedonia]

I should have also added, using a butterfly valve also improves cylinder cooling when partially closed.

 

[riseric]

Showplanes

I use this, with their oil cooler mount
(no affiliation to them)

Works flawlessly from -20C to high summer temps in keeping the oil in the 180-200°F range while in cruise at any level.
Probably not mandatory to have but I find it useful when flying in all 4 seasons in Canada and further south.
I admit that keeping the cylinder temps in range in extreme weather is more challenging.

 

[Mconner7]

I added a ground adjustable piece of aluminum at the aft baffle that closes off part of the flow on my 540. I restrict the airflow to almost 1/2 and the oil temp stays around 190 in cruise.

My logic was, why work hard on sealing baffles if you are going to waste cylinder cooling air through a 4” hole going to the oil cooler and then have the vernatherm bypass oil from the cooler to keep it warm.

 

[lr172]

...why work hard on sealing baffles if you are going to waste cylinder cooling air through a 4” hole going to the oil cooler and then have the vernatherm bypass oil from the cooler to keep it warm.

The answer to that question is "headroom." You want excess cooling capacity that can be used or not used by the thermostat, as needed. If you restrict airflow so that the vernatherm is always open under normal operating conditions, what happens when something goes wrong and the engine starts generating more heat or cooling flow is partially restricted or your in the mojave with 125* ambients? I can think of numerous things. If you have excess cooling capacity, the thermostat just opens up more and issue averted. There is a reason we have a thermostat in this system, as opposed to designing a cooler and air flow to a single heat rejection rate.

 

[DanH]

My logic was, why work hard on sealing baffles if you are going to waste cylinder cooling air through a 4” hole going to the oil cooler and then have the vernatherm bypass oil from the cooler to keep it warm.

I think Mark makes a pretty good point.

Headroom for the what ifs?. Same situation as a cowl flap/variable exit. Size the smallest area to result in the highest approved temperatures at the worst likely OAT. Put another way, can you limp home safely? If so, it's done right.

One reason I recommended flying a while, and only then making changes, is the opportunity to find limits iteratively. For example, prior to fabricating the variable exit, I had already flown quite a lot with progressively smaller fixed exits. In the end I flew the Ripon approach at 90 and taxied to HBC with a fixed exit equal to available area with a closed exit door. Arrived at the parking space with oil at max, but not more, thus no fear of door failure.

In this case the OP could fly four seasons with simple flat plate air blockers and know exactly what he needs.

Never hurts to earn the "experimental" label.

In the summer heat with the valve open, I haven’t seen above 220 in an extended WOT climb. As far as control, I have no issues maintaining the recommended 190 degree temp.

At 220 I'd want more cooler capacity, but opinions vary. Yes, it's below max, quite common, and even recommended by some.

The recommended cruise temp 180F for the OP's 390.

 

[BillL]

Good idea, but not a universal solution.

I added a ground adjustable piece of aluminum at the aft baffle that closes off part of the flow on my 540. I restrict the airflow to almost 1/2 and the oil temp stays around 190 in cruise.

My logic was, why work hard on sealing baffles if you are going to waste cylinder cooling air through a 4” hole going to the oil cooler and then have the vernatherm bypass oil from the cooler to keep it warm.

Depends on your mission range expectations. You could leave home at 70F, stop for fuel once and land in -40F in half a day. No time to be removing the cowl and adjusting something. In 0F cruise, my 7 can not tolerate any air on the front of the cooler. Yes, it is a parallel valve, no squirters.

As mentioned you need all the air when hot, much less when cold.

 

[rocketman1988]

I think Mark makes a pretty good point.

Headroom for the what ifs?. Same situation as a cowl flap/variable exit. Size the smallest area to result in the highest approved temperatures at the worst likely OAT. Put another way, can you limp home safely? If so, it's done right.

One reason I recommended flying a while, and only then making changes, is the opportunity to find limits iteratively. For example, prior to fabricating the variable exit, I had already flown quite a lot with progressively smaller fixed exits. In the end I flew the Ripon approach at 90 and taxied to HBC with a fixed exit equal to available area with a closed exit door. Arrived at the parking space with oil at max, but not more, thus no fear of door failure.

In this case the OP could fly four seasons with simple flat plate air blockers and know exactly what he needs.

Never hurts to earn the "experimental" label.



At 220 I'd want more cooler capacity, but opinions vary. Yes, it's below max, quite common, and even recommended by some.

The recommended cruise temp 180F for the OP's 390.

190 degrees recommended for my IO540 by the engine builder (who dictates the warranty terms, lol)

The only time I saw 220 was giving rides,doing multiple tol’s at an ambient temperature above 90 degrees. Normally, I never see much above 200 and yes I have a larger cooler installed. Where the valve comes into play is cross county flights above 10k, especially in the winter.

Yes, I can see a#6 cht change when using the valve.

 

[dmattmul]

Interesting observation

I should have also added, using a butterfly valve also improves cylinder cooling when partially closed.

I'm guessing this could be possible as the butterfly might disrupt the airflow taking it from laminar to turbulent flow and such better heat transfer coefficients? Or possibly just diverting the airflow to a hotter section of the engine? Either way something to explore. Roughly how much is it closed and have you looked at your actual butterfly position when set this way? Thanks for the input.

 

[Desert Rat]

Holy cow guys- I didn't expect there to be so much passion around this.

To clarify a couple of points;

I've got a 13 row oil cooler on the firewall in an RV10 plenum box. The plan is to duct air from behind #4, as so many other folks have done.

I've got a pull cable from the panel out there with the intent of doing a butterfly valve, but started questioning that plan for a few reasons.

1- The Airflow systems butterfly has 4 mounting ears on the flange and it would make my life easier if they were clocked differently. The easiest way to get it clocked correctly would be to cut it apart and re-weld it in a different orientation. I can't weld aluminum, so that seems like a hassle.

2- Already mentioned that the lever arm is just held on by a friction screw.

3- The throat is effectively twice as tall as the simple Vans 4" flange, which seems like it would require a tighter bend of the skeet tubing as it makes it's way up and over the engine mount. Bends=Bad for airflow.

4- I'm using a RV14 baffle kit, and it comes with a honking big 5" hole behind #3 thats supposed to be ducted to the RV14 oil cooler, so clearly at least in their OEM design for the 14, Vans isn't worried about robbing air from the cylinder fins.

5- There is no provision in the RV14 OEM setup for restricting cooling air through said honking big 5" duct.

I think we all agree that choking off the airflow will cause the oil temp to rise, but taking all that stuff into consideration, especially number 4 & 5, got me questioning if I even need to worry about it?

As far as a mission profile that would have me taking off at 70F and landing a -40F...let me just say forget that. If it's below zeroF I'm staying home

Based on all the comments, I think maybe I'm going to skip it for now and see what the first winter brings. I think Dan's suggestion of just playing with it to see what I need is a good one.

If I can keep oil temp above 160-ish up high in the winter I'll call it done. If not, I'll go back and add some sort of butterfly or whatever.

Thanks to everybody for their input

 

[Desert Rat]

I'm guessing this could be possible as the butterfly might disrupt the airflow taking it from laminar to turbulent flow and such better heat transfer coefficients? Or possibly just diverting the airflow to a hotter section of the engine? Either way something to explore. Roughly how much is it closed and have you looked at your actual butterfly position when set this way? Thanks for the input.

I think that it's probably just that if you have less air going through the oil cooler, you're forcing more to go through the cylinder cooling fins.

 

[Webb]

You can fix the friction screw by drilling the arm and shaft and putting a cotter key in.

 

[dmattmul]

+1

That's what I did. You do not want this to accidently close. With a angle valve engine the oil gets hot very quickly !! In Ohio I had mine closed for warm up and took off and within 30 secs (Or less) got a high oil temp alarm. (It's part of my checklist now)

 

[DanH]

Holy cow guys- I didn't expect there to be so much passion around this.

Meh.

The plan is to duct air from behind #4, as so many other folks have done.
4- I'm using a RV14 baffle kit, and it comes with a honking big 5" hole behind #3 thats supposed to be ducted to the RV14 oil cooler, so clearly at least in their OEM design for the 14, Vans isn't worried about robbing air from the cylinder fins.

The aft face of #3 is the intake valve side, with little fin depth. The aft face of #4 (or #6) is the exhaust side, with deep fins and a serious airflow requirement. And #3 requires less bend in the SCEET tube. I'm just sayin'...

There is no provision in the RV14 OEM setup for restricting cooling air through said honking big 5" duct.

The version with a 5" duct also has center hinged cowl air door. Closing it reduces mass flow through both the oil cooler and the cylinder fins.

 

[Desert Rat]

I get what your saying about which side is which. If I had thought about that a year ago it might have made a difference. But now it is what it is and air is coming off the left side.

Seems like if the RV14 has a cowl flap, all we're saying is that you need more or less cooling air overall, but the cylinder fin to oil cooler ratio doesn't change. I don't see how thats any different than any other plane with cowl flaps regardless of the oil cooler arrangement.

 

[Mconner7]

Depends on your mission range expectations. You could leave home at 70F, stop for fuel once and land in -40F in half a day. No time to be removing the cowl and adjusting something. In 0F cruise, my 7 can not tolerate any air on the front of the cooler. Yes, it is a parallel valve, no squirters.

As mentioned you need all the air when hot, much less when cold.

I can reach my damper through the oil filler door if I needed but after over four years have never felt the need. YMMV

 

[Pinot 1]

IO-390 Show planes 13 plate cooler

I'm in phase 1 with 20 hours and I have only close the valve to see the effect. The oil heated up to 225 so I opened it and allowed it to settle at 190. There is a thermostat that will maintain that temp on the IO-390. I want the door for colder operation, at altitude. Oil should be 180 to 200 if possible. My engine has piston oil cooling.

I'm installing an IO-390 in my RV 7 and am currently working on the baffles.

I was planning to do the Airflow Systems duct with the butterfly flapper and control it via a cable in the cabin, as I've seen other folks do.

However, looking at this, that flange is about twice as long as the simple Vans flange which came in some kit or another.

Also, I'm not thrilled with the lever arm arrangement on the Airflow unit. The shaft isn't splined, so if the set screw comes loose the butterfly will be free to do it's own thing including potentially closing off the airflow to the cooler.

For those of you who have this arrangement, do you really use the flapper to manage airflow, or is it one of those things that you installed but find that you rarely use?

I guess another way to ask the same question would be; since there isn't any provision for airflow control in the similar setup on the RV14, do people with those planes typically have any issue with low oil temp in winter operations?

I'm including a couple of pix of option A and option B in case this isn't clear.

 

[BillL]

I can reach my damper through the oil filler door if I needed but after over four years have never felt the need. YMMV

That is a great idea! My 7 has the cooler on the left , and admit not thinking about your concept.

 

[gasman]

During the warm season in Northern CA.... Redding area, I have always had to watch CHT during departure and level off to allow the temps to reduce from my 400* limit.

After reading this thread, today I closed my 3" butterfly valve to my oil cooler before the flight started. The OAT was 90* with a DA of over 3K. The departure was my normal and continued to 3k and leveled off. The CHT's stayed at 380*, the coolest they have ever been under the same conditions.... A good 20+* lower than the past.

Forgetting that I closed off the air supply to the cooler, my MGL let me know that the oil temp limit has been reached, so I opened the butterfly and the oil settled down to 181 and the CHT's settled in at 352*.

All is good now that i know where my CH cooling was going and not needed during that short period of time.

Side note..... There has been some conversation here about the failure of the butterfly valve to control oil temps accurately. To that, I will say that during the winter I have been able to set extatically the temp I want to see within limits, with the butterfly valve. My setup is cooler mounted on lower LH firewall with a 3" scat and valve off of #4. The cable is a 1/4 turn to lock from NAPA Auto parts.

From now on, all of my departures (no matter the season) will be with the oil cooler air supply blocked. Your CHT's will climb much faster than your oil temp.....

 

[Vfr1200]

Is this the 4 inch of did power flow come out with a 5 inch butterfly ????

I'm installing an IO-390 in my RV 7 and am currently working on the baffles.

I was planning to do the Airflow Systems duct with the butterfly flapper and control it via a cable in the cabin, as I've seen other folks do.

However, looking at this, that flange is about twice as long as the simple Vans flange which came in some kit or another.

Also, I'm not thrilled with the lever arm arrangement on the Airflow unit. The shaft isn't splined, so if the set screw comes loose the butterfly will be free to do it's own thing including potentially closing off the airflow to the cooler.

For those of you who have this arrangement, do you really use the flapper to manage airflow, or is it one of those things that you installed but find that you rarely use?

I guess another way to ask the same question would be; since there isn't any provision for airflow control in the similar setup on the RV14, do people with those planes typically have any issue with low oil temp in winter operations?

I'm including a couple of pix of option A and option B in case this isn't clear.