REFLECTOR: Cooling the engine

[Ron N Velocity XLFG]

Thanks Scott

>From what I have read so far I think the next step 
is going to be adding a cowling outlet. Nacas are not good at pressurizing ,
they are good fo flow. So I think I need a larger exit than inlet to make them work better.
Makes sense to me.
  ----- Original Message ----- 
  From: Scott Derrick 
  To: reflector at tvbf.org 
  Sent: Tuesday, March 27, 2012 10:26 AM
  Subject: Re: REFLECTOR: Cooling the engine


  I posted this with attached photos and then realized the total was probably way over the list attachment size limit.
  So I put all the referenced photos in this file  http://tnstaafl.net/canards/cooling.zip

  I also found the testing photos of the spillage of air out of the top NACA's 

  http://tnstaafl.net/canards/right_naca_rear.jpg
  http://tnstaafl.net/canards/left_naca_rear.jpg

  Scott


  Ron, 

  I feel your pain. Been that and Done there. 

  I don.t think you'll get any joy from changing the 2-into-1 exhaust. 

  Things I did to get from barely around the pattern before exceeding redline CHT limits to comfortable cruise at 330-380- CHT temps in the summer. 

  1.) Extremely anal about tight plenum and cylinder baffles. no unplanned holes larger than a pencil.  Be sure all you cylinder baffles are in place. 

  2.) Large(half to 3/4 inch high) VG's apx. 6 inches in front of your upper NACA inlets.(vg.jpg) 

  3.) Diverters around the exhaust exits, Air was entering the lower cowling, specially at high angles of attack, increasing the lower cowl pressure which reduced the flow through the cylinders. .(picture attached)  exhaust1 is looking back at it, exhaust2 from the side, left is front. 

  4.) extended the NACA lip, (nacatest.jpg is testing the spillage and shape of the eventual extender, extend.jpg is the extender installed) 

  5.) lower cowl flap. (lowerside is a side view cowling removed. cowlrear is looking dow the business end of the cowl flap) 

  Scott 



  -- 

  Forget injuries, never forget kindnesses. 
  Confucius 


  Ron Velocity XLFG wrote: 
    Well I have to high engine temps and I am working on reducing them.

    Exhaust wrap I have read that they are  good at keeps the heat out of the cowling 
                 Bad may cause a crack in the pipes any one tried this method 
    with success of failure?

    I have a two in to one exhaust that goes next to the oil pan .
    First I was going to wrap the exhaust pipes but now I may consider 
    making two straight pipes out of the engine instead of the two in to one.
    My hope would be cooler engine. any thoughts. I did the two in to one
    with the idea of reducing engine noise but if it is adding heat it must go.

    Tried a few mods to the nacas. None helped most made it worse for 
    cooling.  I had fans to help in cooling on the ground I removed them 
    and it helped in the air but now I must get in the air  a little more quickly now.

    I was going to add a cowling flap I have heard this would help any thoughts?



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