Right metal prop for RV-4

[dan carley]

my friend has a Sensenich 70 cm7s16 (79). prop on his rv4 and he is only getting 150 knots at 2600 rpms flat out at 3500 ft. seems slow for the plane?

thanks
dan carley

[AX-O]

It would help if you can post your bud's rv-4 configuration. i.e. no wheel pants, old wheel pant, short gear with old style gear fairing. Also, is that 150 TAS or IAS?

[Sid Lambert]

Axel is spot on that these numbers are meaningless without more info.

As a reference...

I have the same prop and same pitch on my -4.
WOT at 8500 yields 2710 and 168 kts true. It has Sam James wheel pants with vans cowl.

[Christopher Murphy]

The only fixed pitch metal prop that should be on an RV-4 is the Sensenich designed specifically for faster airplanes

My bone stock 160 rV-4 did 165 ktas all day long at 2600rpm

was 81 pitch

Its too bad it was rpm limited because I think it would have been wicked fast if it could have turned a few hundred more RPMs.

cm

[SHIPCHIEF]

Dan,
That seems about 10 Kts slow based on our experience. I don't have real accuracy, I flew to 8,000 ft density alt and ran at or near full throttle @ 2600 RPM into and away from the reported wind, and averaged the GPS ground speed.
I removed the metal Sensenich (sorry, I don't remember the pitch) and installed their Ground Adjustable Carbon Fiber prop on my wife's 160 HP 1989 built short gear, old wheel pants, sheet metal intersect fairing RV-4. I selected the short 68" diameter. I set the pitch to position 5.
It has nickel leading edges, is that metal enough? It climbs better and is faster, plus feels smoother. Marilyn takes off like a rocket. Could be partly because the plane is light & she weights about 108 Lbs...
I love the CATTO prop on my RV-8 so much I'm upgrading to a 3 blade, but this adjustable thing has a quality all it's own.
I suggest you provide more detail and a picture of your friend's plane (we always love that). Search the archives. Find out if the throttle is wide open or partly closed to keep from exceeding 2600 RPM? Does it have a manifold pressure gauge? Those aren't just for planes with constant speed props anymore! You can figure out % of power with RPM and manifold pressure.