[karlhipp]

Any info out there on the real world cruise speed---8000 feet--on an RV-9 with 150 HP 0-320 AND CONSTANT SPEED PROP?

 

[petehowell]

See tests

Hi Karl - I test after Annuals each year and post here

RV-9A Speed Tests

It will go faster, but I always cruise LOP at 6GPH

 

[Finley Atherton]

If you do a search you should find lots of data for a 160 hp RV-9 (A) but I suspect you would find little for the 150 hp engine. Having said that the two engines should give similar cruise performance at the same fuel flows and with the same leaning technique. Possibly the higher compression 160 hp engine may be slightly more fuel efficient. The main difference is that the 150 hp engine will need to operate at a slightly higher % power to give the same cruise performance as the 160 hp engine.

Page 12 of the CAFE report on Van's 0 320 9A with 160 hp, mags and a CS prop will give you cruise performance data . The TAS figures should be very accurate however I am a little skeptical about the stated fuel flows. Post #9 from this thread gives real world cruise data from Vans for their 9A with 160 hp and a CS prop.

Fin
9A

 

[N941WR]

Same airplane, two different engines:

When I first flew my -9 I had a 135HP O-290-D2 and would cruise at 65% power which would give me 140 Kts/165 MPH with a fixed pitch Catto climb prop.

Later I switched to an O-360 but stayed with a Catto fixed pitch prop, this time it is a cruise pitch. 75% power gets me right to 200 mph / 170 kts.

My typical cruise is 150 to 155 Kts at at around 7.5 GPH LOP.

My climb rate for the 135 HP O-290-D2 was 1100 FPM at gross / 1600 FPM solo. With the O-360 and cruise prop it will do 1600 FPM at gross / 2000+ FPM solo.

The -9 climbs so well it begs the question, why do you want a CS prop?

 

[Jesse]

I have a 150HP O-320 on a -9A and get 150ktas on 6gph at 12,000. I can get 155ktas at 8000, but have to bump up the fuel burn. I have a Sensenich ground adjustable prop set for mid range, I think.

 

[flyboy1963]

similar numbers

My -9a 0-320 150 hp will show about 152 kts below 8000' on the GPS. that's close to full throttle, maybe 2450 rpm, which is all she will do.
I am curious about the Sensenich ground adjust....have you tried the 'fine' limit, where you spin up 2700 rpm plus?
...or the coarse pitch that gives decent cruise, but won't pull full power at 2300 or so?

 

[Jesse]

My -9a 0-320 150 hp will show about 152 kts below 8000' on the GPS. that's close to full throttle, maybe 2450 rpm, which is all she will do.
I am curious about the Sensenich ground adjust....have you tried the 'fine' limit, where you spin up 2700 rpm plus?
...or the coarse pitch that gives decent cruise, but won't pull full power at 2300 or so?

I have only tried the one pitch so far. On takeoff and climb I think we only see about 2400-2500rpm, so there is certainly more climb available with less pitch. There is also possibly better cruise available with more pitch. At 12,000 feet, the rpm was running just under 2600, IIRC, at 18-19", which was WOT. At lower altitudes we are getting less RPM also. I do have plans to do a full test of different pitches and also with a Catto prop after the plane gets out of paint, which will hopefully be by the end of the month. SmokyRay is planning to spend a day with me to do all of the testing and we will plan to post the results. I don't expect to climb to 12,000 feet for each test, but likely to 8,000. We'll see how it goes.

So, in answer to your question, we have not tested the fine pitch or the coarse pitch yet, but are surprisingly happy with the results at the medium pitch that we initially set.

 

[RVbySDI]

My -9a 0-320 150 hp will show about 152 kts below 8000' on the GPS. . .

Is this 152 kts TRUE AIRPSEED or GROUND SPEED? Others are discussing TRUE AIRSPEED. I have not seen a GPS that shows TRUE AIRPSEED so any clarification would be appreciated.

 

[Jesse]

I calculate true airspeed by averaging my groundspeeds going all 4 directions. I have heard that some do 3 directions, but haven't heard that actual procedure.

 

[tc1234c]

Just another reference

My 9A has a 160 hp O-320 with one mag and one lightspeed electronic ignition driving a standard fixed pitch Sensenich propeller (79" pitch). Unless in a dive it will never turn faster than 2,600 rpm. Following is data extracted from several trips in the past year. You will notice that my airplane is not as efficient as Pete Howell's. Fuel burn has a lot to do with the induction system and pilot skill. Usually my EGT spreads are very wide (100 degrees). Since percent power is calculated based on an user entered table, it is for reference only. I sorted the table based on rpm. Fuel burn has something to do with how I leaned it at the moment.

 

[RVbySDI]

My -9a 0-320 150 hp will show about 152 kts below 8000' on the GPS. that's close to full throttle, maybe 2450 rpm, which is all she will do.
I am curious about the Sensenich ground adjust....have you tried the 'fine' limit, where you spin up 2700 rpm plus?
...or the coarse pitch that gives decent cruise, but won't pull full power at 2300 or so?

I calculate true airspeed by averaging my groundspeeds going all 4 directions. I have heard that some do 3 directions, but haven't heard that actual procedure.

I do understand this concept. I have made the same speed tests for calculating my true airspeed using the GPS ground speeds to derive an average true air speed. However, I was inquiring as to what was meant when flyboy1963 stated . . . will show about 152 kts below 8000' on the GPS. This statement is implying the GPS reading showed 152 kts. He did not mention anything about a derived true airspeed he calculated from a GPS speed test. Thus my request for clarification on what speed he was referring to when stating the 152 kts -- TRUE or GROUND SPEED?

 

[flyboy1963]

...I stand to be corrected!

Is this 152 kts TRUE AIRPSEED or GROUND SPEED? Others are discussing TRUE AIRSPEED. I have not seen a GPS that shows TRUE AIRPSEED so any clarification would be appreciated.

yeah, sorry Steve, I just threw that in to the mix. Let's say it was a day close enough to 'standard' with light winds, that I thought the groundspeed would be meaningful to someone.
perhaps not. I wish I had all the data to project some meaningful numbers like Ted.

 

[Rupester]

Still learning about my new 9A, but ...

... after 75 hrs, and using LOP procedures for the last 30-40 or so, I see 145 to 148 ktas at 8000' running ~40F LOP and about 2400 RPM, which shows 6.1 to 6.2 gph. That is in a throttled-back condition. It looks like I could run much closer to WOT at higher altitudes and modulate power with mixture, but I haven't done that yet. Might be more knots lurking there.

(A/C profile: 160HP IO-320, Silverhawk FI; one mag, one Lightspeed, Catto 3-blade.)

Incidentally, the engine/prop combination offers 2700RPM at any altitude up to ~6000', much to my surprise.

 

[PaulR]

Incidentally, the engine/prop combination offers 2700RPM at any altitude up to ~6000', much to my surprise.

Terry,
I'm interested in the pitch of your Catto. Mine on my 9A with an O320 will spin over 2700 quite a little past 6000'. I'm assuming you're talking about MSL? I'd have to look at my numbers when I get home but I think mine will turn 2700 to almost 8000 msl.

I've been thinking about having Craig re-pitch it a little but am undecided.

 

[RVbySDI]

yeah, sorry Steve, I just threw that in to the mix. Let's say it was a day close enough to 'standard' with light winds, that I thought the groundspeed would be meaningful to someone.
perhaps not. I wish I had all the data to project some meaningful numbers like Ted.

Thanks for the clarification.

Terry,
I'm interested in the pitch of your Catto. Mine on my 9A with an O320 will spin over 2700 quite a little past 6000'. I'm assuming you're talking about MSL? I'd have to look at my numbers when I get home but I think mine will turn 2700 to almost 8000 msl.

I've been thinking about having Craig re-pitch it a little but am undecided.

Paul, I am not Terry but this is what I have; I have an ECi IO-340 with a Catto 3-blade 68x72 prop. I have been in discussions with Craig for a year now concerning my pitch. I have done several GPS speed tests at 8000' DA WOT and have easily maintained 2800 RPM - 24.7 MP in straight and level flight. At those settings my best GPS speed tests revealed a True Airspeed of 192 MPH (167 kts).

My thinking is also along Terry's line. I think I am leaving some kts (MPH) on the table and could get more out of my setup than I am currently getting.

A typical flight plan for me will have me cruising anywhere from 4500' - 12,500'. I typically will see around 2500 RPM - 22.2 MP and cruising around 160-165 mph (139-144 kts) TAS. I find I am burning around 6.5-6.9 gph at these settings. I have been on many trips at altitudes in the 11.5 - 14.5 range (yes, using oxygen at these altitudes). Even at these altitudes I can still spin up to around 2500 - 2600 RPM although the MP will be down around 19 or so.