Results 1 to 5 of 5

Thread: Installing a Fan on the Rope Pulley

  1. #1
    Member Bart's Avatar
    Join Date
    Dec 2015
    Location
    Valdez, Alaska
    Posts
    480

    Installing a Fan on the Rope Pulley

    with fall/winter soon showing up. getting the motor on the boat looks like next spring. But I have been looking at a few different things, to help cool the heads on the 084 motor. I don't know how well it will work, but we will see how it goes.
    so last summer when tuning the motor, I had the stock fan mounted and pushing the air towards the motor, but with out the shrouds, it was kind of hit and miss...
    and the head temps were getting up there...
    I had an old 2A042 genset, and up to now I had nothing to compare the 084 head temps against... so I got it going, and with no load, but at 3600 rpms. & all the shrouding. the head temps are around 280 degrees. but as soon as I would remove the top cover. they would shoot up to around 400 in less than a minute. put the shroud back on and they would go down.
    then a few weeks ago I came across an video of Les Smoot's air plane, where he discussed a few things, he mentioned that with his arrow prop. at 3200 rpms. his head temps would stay around 400 to 420, but if the rpms went higher. so would his head temps.
    one really cannot compare the air flow on the motor when the air plane is using a puller prop. and the airboat is using a pusher prop.
    but it is food for thought...
    so in the quest of improving some small things, I am fabbing up a 15" fan onto the rope pulley..
    One thing to be thinking about down the road, is how I will be incorporating and belt driven alternator.
    also I am thinking it may not be enough just to have air flowing horizontal past the cylinders.. on these gensets, the air is exiting by the base head.
    and to do that I will need to add some shrouds, maybe..
    Anyway, it is nice to have a lathe to turn some of these things out. Just to see if they will work, a 3D printer would be fun also..
    the biggest thing is to keep everything concentric to the rope pulley. I am still thinking about how to install the fan shroud so it will keep things clear..
    but I have a few ideas..
    but at the moment with what I have done, it is looking like the leading edge of the shroud will only be 2.5 inches in front of the pulley. and that is better than I thought. with the parts I have. I really cant see getting it any closer..
    I did come across a link with pictures of how one built shrouds for his 084 motor that he has on his plane. It is just fun to start finding more threads on what others have done..
    if this works great, if not, at least it was attempted..
    Attached Images Attached Images        

  2. #2
    Member Bart's Avatar
    Join Date
    Dec 2015
    Location
    Valdez, Alaska
    Posts
    480

    Re: Installing a Fan on the Rope Pulley

    now comes the fun, needing to fab up a shroud, to direct the air.
    I am sure that it will take more than a couple trials and error to fab this up, I did acquire a 24" scroll saw last summer, and I think that it will come in very handy to cut out the pieces.
    I have been looking at what the gentleman did with his airplane, where he used some fabric to help with the corners, I am almost thinking of doing that for the top cover. to keep it lower. and run it under the intake tubes. it would save a big headache in the cutting and fitting dept.
    as it was, I was able to cut out one side. that scroll saw is nice, it doesn't leave a sharp edge. the fit was not bad for the first attempt. I have learned a few things, and who knows how it will end up.
    but at least I should be able to test the motor and run it through the paces with out it getting over heated. That is the plan anyway.
    Attached Images Attached Images   

  3. #3
    New Member
    Join Date
    Oct 2017
    Posts
    21

    Re: Installing a Fan on the Rope Pulley

    You might want to investigate how much RPM that plastic fan blade can handle.

    Roger

  4. #4
    Member Bart's Avatar
    Join Date
    Dec 2015
    Location
    Valdez, Alaska
    Posts
    480

    Re: Installing a Fan on the Rope Pulley

    Quote Originally Posted by GTS225 View Post
    You might want to investigate how much RPM that plastic fan blade can handle.

    Roger
    thanks, there is always something, that I forget to do. I looked all over the web, and any info on the blades rated rpm is very vague, so I sent a email to SPAL tech dept. this morning, to see what they have to say. and if this fan blade is not rated for 3600 rpm. If they would suggest a suitable blade.
    well they are quick to respond. this is what I got

    The max blade RPM when driven by our motors is ~3,000 RPM.
    We do not recommend using the blade as you have shown.

    Kind Regards,
    Brent Chuck
    Application Engineer
    SPAL USA 1731 S.E. Oralabor Road Ankeny, IA 50021-9412
    Tel: (515) 289-7042 | Fax: (515) 289-7069


    I did start the motor up last night, didn't have the computer hooked up to it. so I don't know how high I the rpms went, but I didn't notice any flexing of the blades.. but having it come apart, is the last thing I would want to happen.
    I guess another option is to start looking at used cars fan blades that were mounted on a water pump pulley.

    I can see where the engineer would not recommend, or give his stamp of approval for liability reasons.

    I will keep on building the shroud for the motor, and could use the stock fan on the flywheel for the moment, and will keep looking, for a blade that is rated for 3600 rpm. this blade was close at 3000.
    For the time being, if I keep the rpms under 3000. I should be able to at least see how much air flow I will be getting with a set up like this.

  5. #5
    Super Moderator Corky's Avatar
    Join Date
    Jul 2014
    Location
    Susquehanna river, Dauphin, Pa
    Posts
    1,286

    Re: Installing a Fan on the Rope Pulley

    My thoughts are the same as yours...The fan should be good enough to see if you're heading in the right direction...It'll be interesting just how much each shroud will take the CHT down..

    Aluminum .120 14' X 76" hull
    Teledyne 4a084-4 engine
    Circle S 1.69:1 reduction
    67" Whirlwind "Razor X" prop



Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •