Complications in search of more speed

[Bob Axsom]

I went back into my RVator binder and dug out the article by Van (the Man himself) entitled "The Best Dxxx Prop West of the Pecos - How Much Difference is there Really?". It was an outstanding article with tabulated test results covering seven different props. I have a Hartzell C/S prop that I bought through Vans using the one time per plane prop purchase OEM deal. The blended airfoil prop doesn't cost that much more but you can't buy one according to the agreement with Hartzell if you have already used the "one time per plane prop purchase OEM deal. I called Tech support at Hartzell and found that the hub is common and I can purchase just the plades and have them installed my hub with no technical problem whatsoever. The blades are approximately $3,500 each (or ~$7,000 total) which is more than the completed prop costs in the one time agreement with Van's. The man I talked to at Hartzell said the deal we get through Van's is a VERY special good deal - the prop cost normally is approx. $10,000. It would perhaps be a new buisness opportunity for van's to negotiate an upgrade contract with Hartzell for blades only.

Engine higher compression pistons. I contacted Barrett Precision Engines about power increases. I was told that they can add 9.5:1 compression pistons to replace the stock 8.5:1 pistons and increase horsepower by approximately 7. They can supply higher compression pistons but it will require a change to fuel injection.

Bob Axsom

[Jamie]

Bob:

Why don't you just find someone who's not gonna use the Hartzell/Sensi deal from Vans and just have them order the prop for you?

[the_other_dougreeves]

Originally Posted by Bob Axsom

The blended airfoil prop doesn't cost that much more but you can't buy one according to the agreement with Hartzell if you have already used the "one time per plane prop purchase OEM deal.

Van's information specifies limits on the prop when used with the O-360, but doesn't mention the O-320. Anyone out there using the blended airfoil Hartzell with the O-320?

[Bob Axsom]

Originally Posted by vanplane

Now ask the Hartzell folks what they think about raised compression ratios vs. their props. I think Les Doud had some posts here on the subject...?

Sadly, Hartzell does not have a blended airfoil for the O-320. I asked, but they had good technical reasons why one doesn't exist. At least, not yet.

Item 1 - It is a money deal with me, If I could convince the CFO I would conduct the experiment regardless of what Hartzell had to say about the high compression pistons. In other words I would accept the risk.

Item 2 - Not true. This is from Van's on-line catalog: PROP C2YL-1BF/F7663-4 (I)O-320 diameter: 72" Application: RV-3, RV-4, RV-6/6A, RV-7/7A, RV-8/8A, RV-9/9A

Bob Axsom