Howdy Gang,
Trying to sort out something on my recently-bought/already flying RV-7.
I was wondering if there were any rough "rules of thumb" on what you should be looking for in the difference (if any) between the area of your cowl inlet vs the area of the cowl exhaust?
I have ~46 sq. inches of cowl inlet area and about 49 sq. inches of cowl exhaust area, of which the lower area is further reduced by ~6 sq. inches by the two exhaust pipes that exit there.
Just looking at it...trying to exhaust 46" of intake air into ~43" would seem to explain why I'm experiencing higher than comfortable on takeoff CHT's (420+ at 80 degrees OAT and 2-3000' DA). I'm wondering if I just don't have enough exit area for the hotter, lower pressure air to leave the lower cowl...
Like I said, I was wondering if there were any WAGS on the size/differential between cowl intake and exhaust and if the setup I have now could be driving my CHT issue.
I've already been thru checking FF, mag timing, baffle/baffle seals, etc.
I also have been thru many threads on VAF regarding adding louvers, cowl flaps, etc. The stock cowl from Van's comes with this as a built in issue? Seems strange, if that is the case.
Thanks for any insight,
Rob S.
Trying to sort out something on my recently-bought/already flying RV-7.
I was wondering if there were any rough "rules of thumb" on what you should be looking for in the difference (if any) between the area of your cowl inlet vs the area of the cowl exhaust?
I have ~46 sq. inches of cowl inlet area and about 49 sq. inches of cowl exhaust area, of which the lower area is further reduced by ~6 sq. inches by the two exhaust pipes that exit there.
Just looking at it...trying to exhaust 46" of intake air into ~43" would seem to explain why I'm experiencing higher than comfortable on takeoff CHT's (420+ at 80 degrees OAT and 2-3000' DA). I'm wondering if I just don't have enough exit area for the hotter, lower pressure air to leave the lower cowl...
Like I said, I was wondering if there were any WAGS on the size/differential between cowl intake and exhaust and if the setup I have now could be driving my CHT issue.
I've already been thru checking FF, mag timing, baffle/baffle seals, etc.
I also have been thru many threads on VAF regarding adding louvers, cowl flaps, etc. The stock cowl from Van's comes with this as a built in issue? Seems strange, if that is the case.
Thanks for any insight,
Rob S.
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