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Cowl - Vans, Show Planes, or James?

Webb

Well Known Member
Sponsor
I have the standard Pepto Bismol Vans cowl and it is untouched at this time.

So - trying to decide the direction I want to take.

#1 - Remain with the Vans.
#2 - Sell the Vans (if someone will buy) and go with one of the others.

According to on-line info (for RV8), Vans is $2,100, SP is $1,890, and James is $1,650. Of course with the non-Vans, you have to buy a prop extension so cost pretty much balances out.

Taking into consideration things such as cooling, performance, quality of the product, CG changes, etc... What would you choose and why?
 
Taking into consideration things such as cooling, performance, quality of the product, CG changes, etc... What would you choose and why?

Most folks choose based on personal preference for style, which is fine.

On the practical side, I've seen no measurements which suggest the alternates offer better cooling or speed performance. The -8's CG tends to be biased toward the forward limit, so a shaft extension to accommodate a particular look drives engine and prop choice toward the M1B and composite. Don't even think about a 390 and BA Hartzell with the extended cowls.
 
For the new RV-8 I debated this then stayed with the stock cowl to support the IO-360-M1B horizontal injection (really like the smooth bottom). As Dan points out, even though I got some “no problem” responses from Lycoming on using the associated prop extension for the other options, the engineer in me could not get past the increased side loads imposed on the forward crank bearing.

However, for my first RV-10 and now for my second RV-10 build, I’ll use the James Cowl. I consider the James cowl to be an improvement on the stock RV-10 cowl for drag reduction - and the plane now flying over 10 years has met my expectations. The 14” spinner is also a much better fit for this larger airplane. I note however that this does require a chunk of extra work, and the use of a plenum.

Back to the RV-8 - I can say the baffles have been a PITA to get right. At some point I may retrofit a plenum.

Carl
 
As usual, Professor Horton said what I was hoping to hear. Going stock is also the least expensive. Thank you Dan.
 
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