S

Steve Sampson

Well Known Member
Has anyone got experience of putting a fairing on the lower firewall to enable the outgoing air to make a more orderly acceleration towards its origional speed.

If so do you believe it has given you a perceptable speed advantage?
Any pictures?

Thanks, Steve.
#4478
UK
 
Not only do you want the air to speed up but you also want it to match the direction of the free stream. A curve at the bottom of the firewall is probably one of the biggest and easiest improvements to make in drag reduction.
 
Exit air fairing.

Dustin, we are obviously thinking the same way. I had hoped the post would cause someone to come in with a set of pictures to show us a practical implementation on a -4. I'm dangling the bait again. If they are not forthcoming I will try and tempt some pictures (or the plans) from the -8 community. I think its a standard -8 part.

It looks like some cheap speed or fuel efficiency to me.

Steve
#4478
UK
 
Exit faring

Steve, It's not too complex. Here are some pictures of my firewall.

http://www.rv8.ch/article.php?story=20050407212659525

Unfortunately I had to remove the exit faring due to the design of the engine mount I used. I'll add one back later, before I fly.

20050407212659525_3.JPG
 
Wow Mike, that sure is a big RV4...!!! The RV4 lower cowl has that pesky lower engine mount tube and gascolator that gets in the way of a fairing. I couldn't engineer mine in there. I get plenty of air out anyway, maybe a smaller fairing?

RR
 
exit air smoothness

Just wondering here, but shouldn't the fairing make an airfoil type transition on the top side instead of a 90 degree intersection?
I understand one objective is to smooth the airflow at the engine mount horizontal, but the main objective is to help flow the air exit the cowling.
Maybe it doesn't really matter that much.
So it seems to me the top of the exit fairiing should extend higher on the firewall.
 
Mickey, what is the -8 part number and what gauge? Might be easier to make one for the -4 rather than hack the -8 part up.
Thanks, Steve.
#4478
 
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