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N184JG

Well Known Member
Today while flying at 8000 ft I leaned for max RPM it was 2747 at full power.I have a 3 blade catto on IO360 with cold air ind. ,LASAR ign. AFP fuel inj. and high comp. pistons . Anyone with a like set up what is your max Rpm? I think it should be 2850 !!!!!
 
What you are getting sounds about right. For a data point- I have the same prop but with 76 inch pitch. RV-6/ Superior O-360/ stock setup with one LSE ignition. At 8000 leaned for best power I see in the high 2700s to around 2800. I had Craig make my prop slightly under-pitched for my setup so as not to loose as much low-end performance.
 
I'm running the Superior IO-360, fwd induction, dual mags, 3blade 66x76.
My max rpm range is 2650-2680 @8000.
 
I am running the Catto 66x76 on my Eci 0360/180 with a LS PIII on one side and a mag on the other. At 8000 density and leaned for max rpm she is knocking on 2800 rpm. At lift off here in Prescott (5K+ feet elevation) she is turning between 2200 and 2230 rpm.

Hope this is of value.

Cheers,

db
 
db1yg said:
I am running the Catto 66x76 on my Eci 0360/180 with a LS PIII on one side and a mag on the other. At 8000 density and leaned for max rpm she is knocking on 2800 rpm. At lift off here in Prescott (5K+ feet elevation) she is turning between 2200 and 2230 rpm.

Hope this is of value.

Cheers,

db
Click to expand...

What kind of speed????
 
db1yg said:
I am running the Catto 66x76 on my Eci 0360/180 with a LS PIII on one side and a mag on the other. At 8000 density and leaned for max rpm she is knocking on 2800 rpm. At lift off here in Prescott (5K+ feet elevation) she is turning between 2200 and 2230 rpm.

Hope this is of value.

Cheers,

db
Click to expand...

Can a Sam James cowl + electronic ignition buy me 1000rpm?
I haven't tested this in almost 3 years. I'll go flying this weekend and get some new numbers. I was going by old notes on 3 way flight testing.
All my xc have been lop in my sweet spot.
 
Hi Jim,

It has been a long time since I did any speed runs at 8k density. I normally cruise this airplane at 60-66% power (my sweet spot) and see, depending on altitude (higher with the 9 wing is better) 162 to 166 tas. The last wide open run at 8k density, using a 4 way gps track and Kevin H.'s spread sheet gave me around 176+ tas.

Dan, I bet the EI and James would give you 100 additional rpm.

Cheers,

db
 
Catto RPM

Hi All
I just had Craig Catto re-pitch my 3 blade prop. The new numbers are
2700 rpm max WOT leaned to best RPM's thats all I could get at 8000' 177kts on the gps with a three way average.
O320E2D lyc w/2 Emags and 8.5 to pistons
 
Dayton,

You got me on the top end--with a 320 yet--now that is embarrassing!!

I am also thinking about a little more pitch to get my cruise rpms down somewhat--what pitch did you end up with and do you have Craig's newer designed prop tips or the older (pre-2006) design??

Dan,

Thinking more about the EI, high power runs, and rpm I would have to say that the only benefit would be the hotter spark on the EI and I don't know how much difference that would make at high power. As you are probably aware, most EI's, including the LS, run close to the mag advance when you are running high power/high mp settings. At low power, like my cruise settings of 60-66% where I am only running around 20-21 inches mp with the fp, my EI advance is up around 33-34 degrees. I am convinced that this advance, coupled with the hotter spark is what allows many of us with carbs to cruise smoothly lop. However, we have far more qualified EI specialists on this site who might be able to offer more details.

Cheers,

db
 
db1yg said:
Dayton,

You got me on the top end--with a 320 yet--now that is embarrassing!!

I am also thinking about a little more pitch to get my cruise rpms down somewhat--what pitch did you end up with and do you have Craig's newer designed prop tips or the older (pre-2006) design??

db
Click to expand...

db
Your signature says you fly an RV9A, ( is your speed kts?) Remember that my frontal area is much smaller and the -4 has a different wing than a -9. Horse power and cubes will take you so far then drag reduction becomes more important. I think my -4 is maxed out in the current configuration. The next step is drag reduction, i.e. SJ cowl and wheel pants, new canopy with razorback and full EFIS.

My prop is the older style and Craig said the pitch was about 2” more
 
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I find this thread very interesting. I just bought an RV6A with a Catto and it gets similar rpms as stated here according to prior owner. I had a Catto on my last airplane which had same diameter and less pitch (66X72). The engine was an IO360 with 10 to 1 pistons. Got about 2230 static and about 2750 at altitude. With that much less pitch it seems it should have had higher rpm. Wonder if pusher is part of the reason?
 
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