Why is my RV-9A so slow?

[weissfamily97]

Just bought an RV-9A w/ O-320-D2A.
Seller stated it trued-out at 8,000ft at 140kts and 7.5gph.
Everywhere I've looked indicates this is at least 5kts and more like 10kts slower than most folks report.

So, I took it up to 8000ft, leaned it out, and checked ground speed in 3 cardinal directions.

Sure enough, it came out to 140kts and 7.5gph.
Just had a condition inspection, and everything appears to be rigged properly.
Any ideas what could cause this?

Thanks for your help!

[FORANE]

Ours did 148 kts typically.

What prop?

[weissfamily97]

Catto fixed-pitch wood prop

[rightrudder]

Is it an all-wood prop or wood-core composite? Catto is refining its designs all the time, and no doubt there's greater efficiency/speed to be had with the improvements.

Is your engine 150 hp or 160 hp?

Mine's an IO-320-D1A (160 hp) with a circa-2014 Catto 70x70 prop that will nudge 170 KTAS under the right conditions, but that's spinning at 2850 rpm. My usual performance cruise at about 10,000' DA is 155-157 KTAS at 2700 rpm, burning between 7.5 and 8 gph.

What is your max static rpm?

[Kyle Boatright]

What are the engine RPM and MP at your 140 knot TAS?

[Vlad]

Originally Posted by weissfamily97

Just bought an RV-9A w/ O-320-D2A.
Seller stated it trued-out at 8,000ft at 140kts and 7.5gph.
Everywhere I've looked indicates this is at least 5kts and more like 10kts slower than most folks report.

So, I took it up to 8000ft, leaned it out, and checked ground speed in 3 cardinal directions.

Sure enough, it came out to 140kts and 7.5gph.
Just had a condition inspection, and everything appears to be rigged properly.
Any ideas what could cause this?

Thanks for your help!

Looks normal to me. You can repitch the prop to get those extra few knots folks are reporting but do you need them? The 9 is a wonderful machine for its purpose congratulations and enjoy.

[weissfamily97]

160hp
rpm is between 2300 and 2400.
I have no idea of manifold pressure.

[weissfamily97]

Originally Posted by Vlad

Looks normal to me. You can repitch the prop to get those extra few knots folks are reporting but do you need them? The 9 is a wonderful machine for its purpose congratulations and enjoy.

I agree...love my 9, and I'm going to fly the heck out of it.
I was just concerned if there was something fundamentally wrong with mine, as no one reports speeds these slow.

[Sam I Am]

My 9A has the Sensenich 70CM7S9-0-77 FP that was repitched to 79" in 2008 in front of a Lycoming 0320E2D (150 hp). It will cruise about 10kts faster than you are reporting but climb performance is poor at best. I typically cruise above 10,000 msl so it will take me 11 to 15 min to get there. I commute about 460 miles to KC weekly and glad for the cruise performance. Every good thing comes at the expense of something else.

[scard]

You are in good company. Mine is a little slow too. After over a decade of enjoyment (160hp C/S hartzell), I've only just recently started to ponder where my other 5kts went. I recently spent a weekend checking that the amateur builder rigged it straight. Found nothing there.