Van's Air Force
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PROP PITCH
- Thread starter N184JG
- Start date
pierre smith
Well Known Member
Ours...
......has 66" diameter, 76" pitch, Jim. As you know, it only turns 2200 RPM static but outperforms Van's numbers by several MPH since I asked Craig for max speed. Yesterday, Jenny and I still climbed at over 1500 FPM on the way to Beaufort, S.C. at 140 MPH. Great to see you flying so soon!
Regards,
......has 66" diameter, 76" pitch, Jim. As you know, it only turns 2200 RPM static but outperforms Van's numbers by several MPH since I asked Craig for max speed. Yesterday, Jenny and I still climbed at over 1500 FPM on the way to Beaufort, S.C. at 140 MPH. Great to see you flying so soon!
Regards,
David_Nelson
Well Known Member
On order...
After talking w/ Craig, this is what I ordered:
3-Bladed Wood/Glass Composite Propeller for RV-7A
66" Diameter x 72" Pitch
I0-360-M1B 180HP@2700RPM
Top Speed at Target RPM-205mph@2800rpm
4.375" Finished Propeller Thickness
7" Diameter Prop Flange
SAE-2 Pattern, 1/2" Bolts and3/4" Lugs
After talking w/ Craig, this is what I ordered:
3-Bladed Wood/Glass Composite Propeller for RV-7A
66" Diameter x 72" Pitch
I0-360-M1B 180HP@2700RPM
Top Speed at Target RPM-205mph@2800rpm
4.375" Finished Propeller Thickness
7" Diameter Prop Flange
SAE-2 Pattern, 1/2" Bolts and3/4" Lugs
roadrunner20
Well Known Member
I have the same fwd facing Superior version XP-IO-360 and Craig gave me the 3-blade 66x78. I originally thought I was overpitched but after cleanup of the airframe and fairings I achieve Van's numbers for the 7A.
whifof100ll
Well Known Member
Catto on an RV-6
Craig recommended a 66 x 74 for a XP 360 vertical inducion FI engine with one Lightspeed and one mag. He stated I should get 2300 static and 210MPH at 8000" WOT 2700RPM. He expects just less than 200MPH at 2600RPM. He expected I would turn 2800RPM WOT down low.
Sound right?
Regards,
Craig recommended a 66 x 74 for a XP 360 vertical inducion FI engine with one Lightspeed and one mag. He stated I should get 2300 static and 210MPH at 8000" WOT 2700RPM. He expects just less than 200MPH at 2600RPM. He expected I would turn 2800RPM WOT down low.
Sound right?
Regards,
hevansrv7a
Well Known Member
66 x 74 3 blade
I got the 66 x 74 3-blade in the new blade design and my static numbers are lower but my takeoff is just fine. Waiting for decent WX here in MI for more testing. This is a 7A w/ SJ cowl, plenum and pants. So far I think it is too fine a pitch, but haven't been to altitude yet. I over-rev quite easily at sea level or below DA.
Scott Will
Well Known Member
66 x 76
I run a 66 x 76 on my RV-7A, IO-360 (vertical induction). I can easily get Van's numbers now that the airplane is "cleaned up" drag wise but I still can't reach the numbers Craig said I would. That's probably due to the fact that with the prop I can only get about 2660 out of the engine, a few shy of 2700. The RPM has been verified by an external tach. RPM on takeoff is about 2210.
Think I might spring for the prop upgrade this year. I'm doing my instrument training in my plane now and with that prop... it's just all over the place. You constantly have to be on/off the power as the prop loads and unloads so quickly.
I run a 66 x 76 on my RV-7A, IO-360 (vertical induction). I can easily get Van's numbers now that the airplane is "cleaned up" drag wise but I still can't reach the numbers Craig said I would. That's probably due to the fact that with the prop I can only get about 2660 out of the engine, a few shy of 2700. The RPM has been verified by an external tach. RPM on takeoff is about 2210.
Think I might spring for the prop upgrade this year. I'm doing my instrument training in my plane now and with that prop... it's just all over the place. You constantly have to be on/off the power as the prop loads and unloads so quickly.
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A delta of 10mph per 100 rpm at those speeds might be a little optomistic even with a catto prop.
Tom
RV3
1000+ hours on catto 2 blade prop
whifof100ll
Well Known Member
I made a typo in my previous post.
Tom,
He actually stated just under 200MPH at 2500RPM.
If I assume constant efficency from 2500RPM to 2700RPM in cruise that would mean I should get 210*25/27 or 194 MPH.
Believable?
Tom,
He actually stated just under 200MPH at 2500RPM.
If I assume constant efficency from 2500RPM to 2700RPM in cruise that would mean I should get 210*25/27 or 194 MPH.
Believable?
Believable. You're gonna love his prop. Way back when I was one of the first to order a Catto for an RV and I was involved in a lot of the testing and documentation. Back then he was happy with an 8 mph increase per 100rpm until we got into the higher airspeeds 180mph +. BTW the 3 blade was a lot smoother but did not offer any performace advantage to the 2 blade. i doubt if that has changed regardless of all the 3 blade hype out there.
Cheers
whifof100ll
Well Known Member
Only smoother
Thanks Tin Man
Craig told me that the only advantages to the 3 blade was smoother operation and better ground clearance. The 2 blade is only 70 inches vs. 66 for the 3, so it still has adequate ground clearance. I'm sure the two blade is probaly nicer in the event you have to prop start your RV. With a tip up cowl and FI, not something I really want to do anyway. Two blade is also cheaper and delivers quicker, and easier to remove the cowl. It might be the better choice, but in the end, my quest for smoothness won, and I ordered the 3 blade today.
I asked Craig a bit about why he is suggesting a pitch for my 180HP XP 360 with FI and Lightspeed on a light RV at only 74 vs. the 76 that Pierre and others have mentioned. He has recently gone to a wider blade with a flatter pitch that increases effective pitch.
Thanks to all who have contributed here.
Thanks Tin Man
Craig told me that the only advantages to the 3 blade was smoother operation and better ground clearance. The 2 blade is only 70 inches vs. 66 for the 3, so it still has adequate ground clearance. I'm sure the two blade is probaly nicer in the event you have to prop start your RV. With a tip up cowl and FI, not something I really want to do anyway. Two blade is also cheaper and delivers quicker, and easier to remove the cowl. It might be the better choice, but in the end, my quest for smoothness won, and I ordered the 3 blade today.
I asked Craig a bit about why he is suggesting a pitch for my 180HP XP 360 with FI and Lightspeed on a light RV at only 74 vs. the 76 that Pierre and others have mentioned. He has recently gone to a wider blade with a flatter pitch that increases effective pitch.
Thanks to all who have contributed here.
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