REFLECTOR: dual exhaust

[Ron VelocityXLFG]

My best guess for the longer take off is the lack of back pressure.  Some engines need it to 
get good low end torque . Different day may find different results will keep a watch on it.
The only outlets I had were the two opening in the back of the cowling (Standard).
I added another about 12 inches back from the prop on the bottom  . No pictures yet  I just made a 
exit fairing out of dare I say it “aluminum” for now to see if it would help. When I am sure of 
what is working I will make it our of glass.

Ron

From: Alex Balic 
Sent: Thursday, April 12, 2012 10:02 AM
To: 'Ron VelocityXLFG' ; 'Velocity Aircraft Owners and Builders list' 
Subject: RE: REFLECTOR: dual exaust

Hey Ron,

Probably best not to remove the thermostat- the engine will not have any way to control it’s temperature, and you will be burning more fuel-  it is a tempting thing to do, but you might try to replace the thermostat first to see if maybe the old one is faulty.  I guess you got that stumble fixed!

What do you have for outlets now? I am starting with just the factory ones, but have plans to add more- I figure, we have the 2 NACAs feeding the cowling, and the ram scoop feeding it too, and just the 2 small round outlets and whatever can get out around the spinner- certainly not enough.

Strange about the longer takeoff roll but better climb? Let me know if that is a permanent thing- maybe you had more fuel or something? 

Got any video of your flights?

 

Alex

 

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Ron VelocityXLFG
Sent: Thursday, April 12, 2012 8:18 AM
To: Velocity Aircraft Owners and Builders list
Subject: REFLECTOR: dual exaust

 

I got to test my dual exaust last night. Did not really make any more noise than with one exaust 

outlet. Still sounds so cool at least that is what the guys in the hanger say . The most interesting

thing is that my take off roll was more  but my climb out was  much better.

I think I increased my roll out by  2-300 ft  and gained 200 fpm climb. Cooling I think is better because of less 

exaust pipe under the cowling and I added another outlet to the cowling. I am going to try more outlets

to see if I can get the cooling even better. I have heard of removing the thermostat to help in cooling and 

I might try that also. 

 

  I got her up to 175 knots for a short blast, that’s  fastest I have gone yet no flutter but man is the stick

sensitive at that speed. 

 

Ron
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