Fuselage vent

RVbySDI · #1 06-22-2007, 10:17 AM

I am intrigued by Doug's picture on the home page today (June 22nd) of the fuselage vent he took a picture of at Grady's. I am interested in finding out more information about the specific location where this particular vent was placed and on fuselage venting in general. The picture does not quite show where it is located. Doug has informed me that it was on the access cover but I am hoping to get more information. If someone knows more about this particular aircraft could you respond with some information on it? If there are any other pictures I would love to see them also. Are there any of you engineer types who might wish to pipe in on the pros/cons of doing this type of mod?

I appreciate any information anyone may have on this.

dwilson · #2 06-22-2007, 11:14 AM

Quote:

Originally Posted by RVbySDI

I am interested in finding out more information about the specific location where this particular vent was placed and on fuselage venting in general. The picture does not quite show where it is located.
I appreciate any information anyone may have on this.

I am the owner of the "fuselage vented" RV9A.

The vents are an experiment. I keep getting low levels of carbon monoxide in my cockpit unless I have the cabin vents and or the heater open.

I have tried a number of ideas to stop the CO from entering the cabin.

Sealed the firewall.
Tried to seal the bulkhead behind the baggage compartment with duct tape.
Removed the fairings under the horizontal stabilizer. - this one actually worked, but slowed me down and looks tacky.

Then I bought a couple of new inspection plate covers from Van's and drilled some big holes in them and covered the holes with the covers you see in the picture. This looks clunky and it does not solve the problem.

Now the airplane is at Grady's place for a month to get her cloths painted on, so I can't do any more experimenting until I get her home. (Home is in Southwest Washington)

I don't have any more pictures of this "Mod." -- Maybe Doug or Grady could take a few and post them, but I am not sure anybody would really want to do this for real as it does not seem to work for me.

Duane

mburch · #3 06-22-2007, 11:16 AM

Looks to me like it's on the F-824B cover plate. For my RV-7 it's on drawing 44. This is the plate that covers the access hole that lets you get access to the elevator bellcranks inside the very aft-most part of the tailcone.

Edit - doh, beaten to the punch!

mcb

dwilson · #4 06-22-2007, 12:51 PM

Quote:

Originally Posted by mburch

Looks to me like it's on the F-824B cover plate. For my RV-7 it's on drawing 44. This is the plate that covers the access hole that lets you get access to the elevator bellcranks inside the very aft-most part of the tailcone.

Yep! Thats the one!!!

Duane

RVbySDI · #5 06-22-2007, 01:13 PM

Thanks for the posts. I was thinking the intent of this vent was for a speed mod. There had been some posts on other threads referring to the airflow into the cabin/fuselage with no exit causing a drag issue. I was thinking this might have been Duane's way of decreasing this drag.

Duane have you had any success tracking down the source of the CO? perhaps you can find where it is infiltrating the cockpit and stop it at that end.

Bruce · #6 06-22-2007, 06:24 PM

Duane,

I was thinking about using the same type system but I was going to use the RV-10 vent that is sold in the Van's catalog. Put it on a push pull cable on both sides if I had too.
Just some thoughts.

dwilson · #7 06-22-2007, 07:36 PM

Quote:

Originally Posted by RVbySDI

Duane have you had any success tracking down the source of the CO? perhaps you can find where it is infiltrating the cockpit and stop it at that end.

I believe the CO is coming into the fuselage around the elevators. If I put my CO meter in the baggage compartment the level goes up considerably. If I put it up under the dash the level goes down quite quickly.
I would like to try putting some sort of barrier membrane across one of th bulkheads, but the elevator push tube would have to traverse the membrane and I am not sure how to seal around it.

I will have to wait until late July to try anything. Grady will be painting my plane until then!!!

Duane

Tom Navar · #8 06-23-2007, 02:24 PM

For the person that put a vent in the aft aerea of the fuselage in order to eliminate CO from the cockpit: Try turning the vent to face the slipstream, therefore pressurizing the rear of the fuselage. That may reduce your CO in the cockpit.. Cessna did that in their Skywagons many years ago, once they discovered that the CO was coming in throught the tailfeathers. It worked.
Tom Navar
RV8QB
Cessna 180
Pitts S2A