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Lugging? Was this full fine? or at a coarser setting?
I'm all for 3 or more blades because there is more surface area to impart thrust from. Since we have a prop disc limit of 66 inches on our airframe, adding blades is the way to go to improve thrust. There is a limit to the amount of HP a given blade can absorb and transmit. I wouldnt necessarily be opposed to trying a 6 blade variant either, provided we are making full power with our engine, or later with the turbo.
Dave
Bulent Aliev wrote:
I used to have the same prop as Chris IVO Magnum 68" Diameter inflight adjustable. I felt the 3 blade configuration used to lug the engine down. Changed it to two blade (did not want to cut the blades). My takeoff RPM was 6,500-7000.
Buly
On Aug 3, 2007, at 4:15 PM, Mark Steitle wrote:
On 8/3/07, Al Gietzen <ALVentures@cox.net> wrote:
Al,
I think Chris B. brought this up earlier today. I didn't respond, but you mentioned it, so then couldn't resist the urge to comment. To refresh everyone's memory, I have a 20B with a 76" 3-blade constant-speed M/T prop. So, I can dial in the prop speed desired and the prop controller does the rest. With it set to 2500 rpm, I'm seeing 7000 engine rpm on takeoff rolls. (What a sweet sound! It makes those Lycosaurus' sound like farm tractors.) It will turn about 6700 - 6800 during static runups. But this is a c/s prop, so your mileage may vary.
Mark S.
I have found that with my 66" dia – 80" pitch prop my Velocity doesn't move until engine rpm is somewhere upward of 1500 rpm.
I get about 5500 static with my 20B, and about 5600 on takeoff. With adjustable pitch you will want to get some higher numbers.
Hope you find this helpful,
Al
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