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mh53j

Member
I have a RV-4 with a 160 hp 0-320 and a Sensenich 70" prop that limits my engine RPM to 2600. At present the aircraft will true out at about 185 mph at 8000' PA, I would like to know what prop would get me over 200 mph and not completely destroy climb performance? I do have a few small items to clean up aerodynamically. Wood, composite or metal, I'm completely open for suggestions.

Thanks in advance for any help,

Brett
 
I think if you go with more of a climb prop (less pitch) you should get more speed and better climb. Doesn't sound right, but to get full horsepower you need more RPM. You should be able to reach at least 2700 in level cruise. Have you checked your tach for accuracy?
 
Fix other things

May be some airframe drag reduction? Better gear leg fairings, better wheel fairings, check baffles fit and finish. You will go faster and turn more RPMs. Its interrelated.


I have no idea what your plane looks like, old wheel pants for example. Also is it possible your engine is a little down on power. 160 hp is plenty and even if you where a little off the power, it would only make a small difference in speed, but it all adds up. You will not do much better than Sensenich. Its possible the prop is a little over pitched and you could make the pitch shallower to increase RPM, 100 rpm is good for 5 HP which is good for 2 mph. You climb would actually improve. You don't want less RPM. Go to a prop shop and have the pitch measured and call sensenich. My advice is reduce airframe drag first, engine check (timing, plugs, air-filter, baffle seals) and than think about the prop.
 
Guys thanks for the suggestions, I was not real clear when I discussed the 2600 RPM limitation. That limitation is a Sensenich limitation and therefore I'm looking for a prop that I can turn @ 2750.

Thanks again for the help,

Brett
 
I went through 4 different props on my -6 before I found the Catto. Originally I had a Warnke. It was good at low altitude but did not perform well above 10,000'. The Sensenich wood performed great at altitude but sacrificed static rpm and takeoff performance. The Catto 3-blade shortened my takeoff roll by 17% and didn't hurt my cruise at all.
It's going to be difficult to improve on the Sensenich metal prop. Even with the 2600 rpm restriction, it is a good performer.
 
Electronic ignition

Hi Brett,
I have been told by Tracy Saylor, who goes very fast, that electronic ignition will make up to 50 additional RPMs. If you'll add the newer pressure recovery wheelpants (if you don't have them) as well and have a lower pitch as was mentioned, you should get close to 200.
Regards,
 
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