Adventures in mounting an oil cooler in a S1-11

Discussion in 'Pitts Miscellaneous' started by garyg, Feb 28, 2018.

Help Support Biplane Forum by donating using the link above.
  1. Feb 28, 2018 #1

    garyg

    garyg

    garyg

    Well-Known Member Lifetime Supporter

    Joined:
    Nov 3, 2011
    Messages:
    594
    Likes Received:
    89
    I know it is possible. I have seen them installed. Many pictures all helpful but somehow mine seems a little different.

    But I have no clue if this is adequate airflow or how to mount it where it is sitting. I started with a RV baffle kit and the part by the oil cooler is mostly cut out to fit under the cowing. So bracing an oil cooler there would be tough and also trying to attach the oil cooler to the baffles is not really possible due to the engine mount. The upper cowling brace takes even more from this area. I am not even sure if I can find enough baffle space for the plug wires to go through and the magneto cooling duct. I can see why some place the oil cooler in the nose bowl. I am sure if I had a wider angle valve that I could alleviate some of the engine mount issues. I will notch the flanges on the oil cooler some and have the barrel spaces to prevent flange cracking. Also I have ordered up some of those UMPCO clamps from Aviat (Thanks Bill!), just in case.

    Just a note on the RV baffle kit. It is all aluminum and it seems it will be very susceptible to fatigue cracking. I think it should be steel.

    Anyway I have crudely tie wrapped the oil cooler to a possible position. Any thoughts?

    IMG_1607.jpg

    IMG_1604.jpg
     
  2. Feb 28, 2018 #2

    cwilliamrose

    cwilliamrose

    cwilliamrose

    Well-Known Member Lifetime Supporter

    Joined:
    Nov 10, 2009
    Messages:
    7,587
    Likes Received:
    1,635
    Location:
    SW Florida (94FL)
    Have you looked at the S-2B oil cooler installation?

    S-2B Oil Cooler Installation.jpg

    S-2B Oil Cooler1.jpg

    S-2B Oil Cooler2.jpg
     
  3. Feb 28, 2018 #3

    garyg

    garyg

    garyg

    Well-Known Member Lifetime Supporter

    Joined:
    Nov 3, 2011
    Messages:
    594
    Likes Received:
    89
    Bill,

    Yeah but I dont have that kind of access to the firewall. I asked Aviat about the price of that upper oil cooler clamp ($200) and thought about making my own lower brace. I have a duct that would come off the rear baffle from the original engine. There is hardley enogh baffle to attach it and it hits the engine mount so I would have to modify it I went that way. Dan's sort of attaches that way and he is using a similiar dual pass oil cooler (a lot smaller that way). I am not sure if his fits better because of the wider engine or my lack of trying/understanding. I keep looking at it hoping I will have some kind of epiphany but none yet. I might be able to make some sort of H bracket for the upper going to the firewall though.

    Is that angle downward enough for the exit air? Or should it be angle downward more?
     
  4. Feb 28, 2018 #4

    cwilliamrose

    cwilliamrose

    cwilliamrose

    Well-Known Member Lifetime Supporter

    Joined:
    Nov 10, 2009
    Messages:
    7,587
    Likes Received:
    1,635
    Location:
    SW Florida (94FL)
    Seems to be enough for the S-2B. You could make the cutout in the baffle any shape you need to gain some meat width-wise. The factory used the available space, if yours is narrower maybe you could make yours taller to achieve the same area.

    You don't have a lot of room behind the cooler but it would be great to have a dedicated exit for the cooler rather than dumping the exit air into the FWF area.
     
  5. Feb 28, 2018 #5

    garyg

    garyg

    garyg

    Well-Known Member Lifetime Supporter

    Joined:
    Nov 3, 2011
    Messages:
    594
    Likes Received:
    89
    Bill,

    Yeah right now I have the cooler sitting sideways, somewhat to get clearance. When I try to go vertical, I end up at a pretty downward angle and very close to the engine, so I question how I can get the duct to work. Vertical room is very limited. I will take a picture with it hung vertically. I know the gear engine mount is shorter than stock by 0.407 inches as well (per mount drawing). I dont know what effect that has on the shape of the cross tubes. It does look like the S2-B has much higher angles on the mount tubes. I assume it is a shorter mount.
     
  6. Feb 28, 2018 #6

    garyg

    garyg

    garyg

    Well-Known Member Lifetime Supporter

    Joined:
    Nov 3, 2011
    Messages:
    594
    Likes Received:
    89
    I do have a picture of Dan's oil cooler. I think there is something different about both my cooler and the engine width that makes this harder for me. Maybe I should try harder to look more like Dan's. (Dan, hope you don't mind me posting your photo). I know when I tried the original Aztec baffle here the mount for the duct would not clear the mount both vertically and horizontally.

    photo 4.jpg
     
  7. Feb 28, 2018 #7

    cwilliamrose

    cwilliamrose

    cwilliamrose

    Well-Known Member Lifetime Supporter

    Joined:
    Nov 10, 2009
    Messages:
    7,587
    Likes Received:
    1,635
    Location:
    SW Florida (94FL)
    Looks like Dan has a second oil cooler exiting through the louvers.
     
  8. Feb 28, 2018 #8

    garyg

    garyg

    garyg

    Well-Known Member Lifetime Supporter

    Joined:
    Nov 3, 2011
    Messages:
    594
    Likes Received:
    89

    Yes. I believe he said that one was originally mounted forward but wasn't doing much so he relocated it. I never do see the cooling duct to it. I would like to place mine like that and have it be the only one.
     
  9. Feb 28, 2018 #9

    DanSalcedo

    DanSalcedo

    DanSalcedo

    Supporting Member Supporting Member

    Joined:
    Dec 11, 2008
    Messages:
    229
    Likes Received:
    31
    The cooler next to the louver has a 3" scat from behind the right aft cylinder.
    And the two aluminum straps connected to the upper cooler have been replaced with something more substantial. When I had the cooler in the front, it was real small, I had a second 3 inch running to the lower cooler fed from the left side cylinder.
    Dan
     
  10. Feb 28, 2018 #10

    garyg

    garyg

    garyg

    Well-Known Member Lifetime Supporter

    Joined:
    Nov 3, 2011
    Messages:
    594
    Likes Received:
    89
    Yeah now I remember you telling me about the right hand scat tube for the lower cooler. One of the oil coolers is a dual pass (lower one?). Not sure about the baffle one. When I hold my cooler up like the baffle one I wasn't quite sure 2 straps like that would be very strong.
     
    Last edited: Feb 28, 2018
  11. Feb 28, 2018 #11

    DanSalcedo

    DanSalcedo

    DanSalcedo

    Supporting Member Supporting Member

    Joined:
    Dec 11, 2008
    Messages:
    229
    Likes Received:
    31
    I had to remade them used aluminum bent to a 90 angle. 063
     
  12. Mar 13, 2018 #12

    garyg

    garyg

    garyg

    Well-Known Member Lifetime Supporter

    Joined:
    Nov 3, 2011
    Messages:
    594
    Likes Received:
    89
    So I went back to the Aztec duct and tried again. The duct is pretty large but it is the size of the oil cooler area, it is about a 90 degree duct which I could trim down to say a 60 degree or so to keep it pointing toward the exit (or leave as is?). I am not sure about room for the plug wires per RV baffle kit but I think the Aztec had them inward of the duct anyway and I think I can do that as well. So leave at 90? or Take a little off? I am sure I could get this polished up to look pretty spiffy. maybe a spot of paint. I avoided it originally because when I put the Aztec baffles in and fit the duct it was never going to work. Using the RV rear baffle, I can move the baffle downward. Is it ok to have oil cooler opening in baffle extending over a significant portion of the cylinder head fins?

    Aztec doesn't appear to have any oil temp issues. Even with a turbo. No matter what though the engine mount tubing will cross the exit of the oil cooler at a close distance (cooler not held up all the way but close).

    Any suggestions on the angle?

    IMG_1608.jpg

    IMG_1609.jpg
     
    Last edited: Mar 13, 2018
  13. Mar 13, 2018 #13

    PittsDriver68

    PittsDriver68

    PittsDriver68

    Well-Known Member

    Joined:
    Jan 9, 2013
    Messages:
    4,055
    Likes Received:
    1,110
    I suggest trimming the duct to 60 degrees of turn and mounting the oil cooler cantilevered from the engine mount tubes in the manner that you are thinking of. If the tube is an inch or two from the face of the oil cooler the flow will likely not be restricted.

    Actually, that duct looks oversized for the flow you need. And you will be stealing cooling air from cylinder #6. You can make a duct just like the one that you have that starts out smaller and then gets wider to meet the full face of the oil cooler. Cut the side pieces and then inner and outer curved parts with flanges that you bend over the side parts and rivet together. An expanding duct slows the airflow which is good for the operation of the cooler.

    Don't bolt the oil cooler to the duct. The engine and baffling will move so put some baffle seal at the cooler end of the duct. With the cooler bolted to the engine mount and thus isolated from the engine movement and vibration, it will last longer.

    Best of luck,

    Wes
     
    Last edited: Mar 13, 2018
  14. Mar 13, 2018 #14

    tdwrv8

    tdwrv8

    tdwrv8

    Registered Users

    Joined:
    Dec 11, 2013
    Messages:
    63
    Likes Received:
    16
    Actually #6 will run cooler than the others due to such a large flow across the fins. My #4 on IO360 runs 50 degrees cooler as does most RV's that have the baffle mounted cooler.
     
  15. Mar 13, 2018 #15

    garyg

    garyg

    garyg

    Well-Known Member Lifetime Supporter

    Joined:
    Nov 3, 2011
    Messages:
    594
    Likes Received:
    89
    Wes,

    That duct was made for that exact cooler, so by rights it is not oversized but it does open air up to the whole face of the cooler. But I get the idea of slimming down the open end and letting the air hit the full face on the oil cooler on the other. I will trim to 60 degrees or so. In the Aztec, the baffle bolts to the cooler face and there is a rubber seal attached to the holes shown at the oil cooler end in the picture. But this duct actually mounts to exhaust side of the cooler as the cooler itself is bolted to the engine baffle. I just reversed the duct in the picture because it was easier to clamp to the baffle. If I mount to oil cooler as before, I could still use a rubber seal between duct and the baffle as I plan to mount cooler to the engine tubes if I ever figure out how to do it.

    One thing about using a dual pass sideways oil cooler like this is the inner side wants to come mighty close to the magneto and that is where the hoses attach to it. The duct pretty much says where exactly the cooler needs to be mounted since it can only be mounted in one place. Hope the magnetos don't squirrel around too much at the mount end. I think when laid flat, the cooler actually comes under the magneto slightly. I will recheck that angle tonight. My 11 yr, 11 month and 2 day old very diabetic Rottweiler had a rough start to the night last night, so I went home to keep her company. Maybe she will feel better tonight and give me more time but I don't think time is on her side these days.

    gjg
     
    Last edited: Mar 13, 2018
  16. Mar 13, 2018 #16

    garyg

    garyg

    garyg

    Well-Known Member Lifetime Supporter

    Joined:
    Nov 3, 2011
    Messages:
    594
    Likes Received:
    89
    I was thinking that the might be true. It is giving it a pretty brisk air flow past number 6. So if I reduce the fat end by 20-30 % or so, trim the angle back to 60 degrees and get it re-welded, it would make a pretty good duct.

    Or use as a pattern and make a carbon fiber duct from it.......as we all know how much faster carbon fiber is, even for the most trivial of parts.

    Now if I could figure out how to make a square oil cooler bolt to round tubes going in an increasingly wrong direction.

    gjg
     
  17. Mar 14, 2018 #17

    PittsDriver68

    PittsDriver68

    PittsDriver68

    Well-Known Member

    Joined:
    Jan 9, 2013
    Messages:
    4,055
    Likes Received:
    1,110
    If you build a duct from scratch, either in aluminum or carbon, you could joggle a little outboard to get clearance from the magneto. From the picture it looks like you might gain an inch or so.

    For ideas on mounting the cooler, you might look under the hood of an S-2C to see their solution to the problem.

    And I should mention that the S-2A dumps air from the cooler across two engine mount tubes right behind it. The cross tubes are just over an inch aft of the cooler. Seems to flow OK.

    Best of luck,

    Wes
     
  18. Mar 14, 2018 #18

    Skybolt31

    Skybolt31

    Skybolt31

    Registered Users

    Joined:
    Aug 28, 2006
    Messages:
    1,248
    Likes Received:
    314
    You did good to keep her company, hoping she had a better night tonight.
     
  19. Mar 14, 2018 #19

    garyg

    garyg

    garyg

    Well-Known Member Lifetime Supporter

    Joined:
    Nov 3, 2011
    Messages:
    594
    Likes Received:
    89

    She still has mostly good days....but occasionally she has a day or two. She never misses a meal though!

    she is a little blind. We have to help get up and she has a problem squatting without falling down. But we worked out a code where she barks and I come and help out. Sort of like Pavlov's human. We used to walk twice a day for more than 2 miles each in every kind of weather imaginable from minus whatever to plus 100 to 30 mile an hour winds and raining like crazy from when she was 6 months old to about a year ago. then it was down to a half mile twice a day. Since fall she hasn't walked much at all. But I bet we have walked well over 10,000 miles. And she absolutely hates to run since she was a puppy. I used to throw a ball and after 2 trips to fetch it she wouldn't let me have it anymore. Eventually she would never let me have it without effort. I think in her mind if I really wanted the ball, I shouldn't throw it.

    Twice daily 35cc of insulin for 6+ years means you don't get to travel far without someone staying at home with her. But she is a tough one.

    any way that is my dog story.....
     
    Skybolt31 likes this.
  20. Mar 14, 2018 #20

    jstreat

    jstreat

    jstreat

    Well-Known Member

    Joined:
    Feb 18, 2011
    Messages:
    642
    Likes Received:
    185
    GaryG, you can try all the ducts and coolers above, but chances are you will still run hot. I have never had a S1 that would run cool, even with two coolers. I have mounted them in front, on the side, in the upper left like and S1T and S2B. Never got the temp below 200F during acro. I have hit 245F at contests. Burnt oil!

    On my SS-300 I started with duct work out of the left upper corner into a 17 row Pacific oil cooler. The biggest on the market. After 15 min flying straight and level, I was pushing redline. Ended up putting the cooler down low just in front of the cowl flap. Ended up with two 2" ducts from the nose into a 'Y" plenum. My temps now are 175-180F all day long. To cold on cool days. Here are few pics. I also have hot sump cooling, don't know how much I get, but Kevin Murray agrees it was free.

    JST

    NX397JT_686-2016.jpg

    NX397JT_685-2016.jpg
     

Share This Page