nose wheel lower cowling fairing-Manometer

[Kenny Gene]

Guys,

I have about 90 hours on my 10 now and I'm still having high CHT and oil temps. I have the SJ cowl (and Plenum) which Will James built 6" cooling inlets rings and I moved my oil cooler (SW10631S) directly behind #6 cylinder. I flew yesterday late afternoon in the hot 97 degree Kansas and CHT 422 and oil temp 223.
(Barrett I0-540 275 hp (9:1), dual lightspeed, vetterman exhaust with heat muffs)

Several have suggested I cover the nose wheel slot to keep that pressure air out of the lower cowl and keep from mixing with exiting air. Also, I have seen and have pictures of Jim Smiths exit/exhaust air fairing he built on his 6 and can do something similiar for exit air.

QUESTION, Has anyone done this (built a moveable nose wheel fairing to cover the lower cowl slot) and be kind enough to post pictures?

Also, I would like to purchase a manometer to test plenum pressure air and lower cowl pressure, to be certain I have pressure differential to start with.

QUESTION, Where and Which one?

Thank you in advance for your help and input.

Kenny Gene
RV 7a 660 hrs
RV10 90 hrs

[Wayne Gillispie]

I have this one and like it alot.

http://www.amazon.com/gp/aw/d/B002R1...063702-8722023

Just run some 1/4" plastic/aluminum tubing to the desired location. Please post your results.

I am thinking about some type of flexible rubber/silicone boot with some type of stiffener/reinforcement for bottom of cowl. I am just now finished with cowl for now. I can understand why those short lower hinges crack. The bottom is too thin and flimsy for the volume/velocity/angle of airflow. As I understand from a recent post there are some others working on this too.

Right now I am just concentrating on getting finished.

[Bill.Peyton]

Wayne,
The Piper cowl has a metal reenforcement that runs along the rear bottom edge of the cowl opening. It is held on with 8 #6 CS screws. When I get down to the hange I will take a photo of it.
Bill

[Tom Martin]

Kenny
I closed the slot using an aluminum and baffle seal sandwich. It was made in two pieces, forward and aft of the leg. On both pieces the metal goes app. one inch to half and inch away from the gear leg. More fore and aft and less side to side. The baffle seal was made with over lapping pieces that rest against the gear leg. The gear leg can move up and down and the overlapping pieces, two front and two rear, allow the baffle seal to move. The pressure in the lower cowling keeps the seal against the gear leg. I used 40 thou material to make the metal pieces with a 63 thou insert to mimic the fibre glass cut out. This makes the piece flush with the cowling. The inserts are held in place with six screws and nutplates on each piece. These inserts stiffen the lower cowling so that the aft brace is not required. The aft brace adds drag to the outlet area and will likely not stand the test of time.
I also sealed the lower forward gear leg with foam to keep air from moving into the lower cowling through the gear faring.
The cowling extends aft of the firewall by about two or three inches and NO louvers were used.
Oil temps are in the 190 range most days with 200+ on hot muggy days.

A great deal of time was spent on the inlets and sealing the plenum. In this case I used the cowling for the top of the plenum, in the traditional manner.

Make sure that your inlets, and plenum top are well sealed. Also check for leaks around the lower baffles.

[Wayne Gillispie]

Bill, looking forward to pics.

Tom, sounds great.

I did intall the louver pieces but did not cut oval slots in the fg at this time. Coated inside of cowl with epoxy. Ready to tackle baffles.

[airbal]

I recommend a Magnehelic Gauge instead of a manometer. I have been using them for years and they are much better for field use (such as measurements in flying aircraft) than a manometer and more convenient. Go to Davis Instruments and get a 0-15" range gauge for about $70.00.

warren