Van's Air Force
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Sam James Cowling
- Thread starter pdr
- Start date
FWIW
Mine did not fit well. It added time to the build and was generally an inferior product. If you want that look, visit showplanes.com and check out his version. Someone posted the other day that Bob at Fairings, etc could modify Vans cowl to have the same appearance as the SJ cowl, but I have no info. My speed did not change. Just a bunch of hype, IMHO.
Mine did not fit well. It added time to the build and was generally an inferior product. If you want that look, visit showplanes.com and check out his version. Someone posted the other day that Bob at Fairings, etc could modify Vans cowl to have the same appearance as the SJ cowl, but I have no info. My speed did not change. Just a bunch of hype, IMHO.
hevansrv7a
Well Known Member
Why?
I have the Superior XP-IO-360 plus on a -7A. In the Michigan summer my oil temp was 180. Now that it's fall, I have a hard time maintaining oil temp and just put on an oil cooler block for the winter. I'm using the standard el cheapo oil cooler from Van's. Right out of the box, my cylinder temps were and have remained low. I've never seen one over 380. The max CHT spread is usually 20-25 degrees without any tweaking. This was true even during break-in. (Using GRT EIS and EFIS for data). My left side cylinders are within 5 degrees. The spread is between the front and rear on the right side. I've modified the ramp in front of #1 to see if that will equalize them. If you average the right side, you get the same temp as the two on the left. Sam says I could do better if I'd just follow his instructions for lower gap on baffles, but I used cut-down Van's baffles from the FWFWD kit instead. He's right, I'm sure, I'm just not ready to spend the time it would take to add material to the bottom ones. Maybe later.
I cannot compare before and after, but I'd be shocked if the SJ cowl with plenum did not deliver some knots. It has a much more streamlined shape and uses less air to do equal or better cooling. Cooling drag slows you down. Dick Martin, in his RV-8 with a BIG engine is using even smaller inlets than the standard ones from SJ. You cannot do this (reduce air intake) if you are not using the air more efficiently. There's a lot of BTU's to shed and more in Dick's than mine.
I'm running without any fairings and my 8-9000' DA 75% is 156 kts true and verified. This is at 2700 rpm, FP Prince prop. It's impossible at this point for me to fully evaluate speed. I'll post more when I know.
Regarding Robby's comments, I like and respect Robby, but I think that many others, me included, have the opposite - i.e. favorable - opinion of the James cowls. Do your due diligence. There are lots of comments on the VAF site about SJ cowls and wheel fairings.
Mine, with plenum, cools very well. I suspect it cools better than a Van's cowl. Why would you use only half of the solution that Sam designed?pdr said:
I have the Superior XP-IO-360 plus on a -7A. In the Michigan summer my oil temp was 180. Now that it's fall, I have a hard time maintaining oil temp and just put on an oil cooler block for the winter. I'm using the standard el cheapo oil cooler from Van's. Right out of the box, my cylinder temps were and have remained low. I've never seen one over 380. The max CHT spread is usually 20-25 degrees without any tweaking. This was true even during break-in. (Using GRT EIS and EFIS for data). My left side cylinders are within 5 degrees. The spread is between the front and rear on the right side. I've modified the ramp in front of #1 to see if that will equalize them. If you average the right side, you get the same temp as the two on the left. Sam says I could do better if I'd just follow his instructions for lower gap on baffles, but I used cut-down Van's baffles from the FWFWD kit instead. He's right, I'm sure, I'm just not ready to spend the time it would take to add material to the bottom ones. Maybe later.
I cannot compare before and after, but I'd be shocked if the SJ cowl with plenum did not deliver some knots. It has a much more streamlined shape and uses less air to do equal or better cooling. Cooling drag slows you down. Dick Martin, in his RV-8 with a BIG engine is using even smaller inlets than the standard ones from SJ. You cannot do this (reduce air intake) if you are not using the air more efficiently. There's a lot of BTU's to shed and more in Dick's than mine.
I'm running without any fairings and my 8-9000' DA 75% is 156 kts true and verified. This is at 2700 rpm, FP Prince prop. It's impossible at this point for me to fully evaluate speed. I'll post more when I know.
Regarding Robby's comments, I like and respect Robby, but I think that many others, me included, have the opposite - i.e. favorable - opinion of the James cowls. Do your due diligence. There are lots of comments on the VAF site about SJ cowls and wheel fairings.
