Two blade or Three blade?

[gsxrpilot]

1 hour ago, RobertGary1 said:

You've probably been to nice well maintained grass fields. Nothing wrong with those, but they aren't the majority in my experience. Most don't have tractors to keep the field smooth or have pilots who care. If they're flying taildraggers they don't mind the ruts and holes.

-Robert

LOL you gotta come hang out at better grass strips 

[Raptor05121]

16 hours ago, rbridges said:

people pay thousands for 1-2 knot speed mods.    I do agree with the ramp appeal.  A 3 blade looks good.  I think it's a mental thing for me, but I opt for best cruise speeds.  

1-2 knots is inconsequential. My friend has a Comanche 260. We both took off from our home airport and flew 150 miles south. I was in the air 2-3 minutes before him. He had 20 knots on me in cruise. He landed 2-3 minutes before me after 150 miles. So all in all 4-6 minutes for 20 knots with a big old honkin 6 cyl sucking down 12gph. You'd be lucky to get out of eyeshot with 1-2 knots at the same distance. Matter of fact, I climb at least 150-250fpm faster, so time to TOC is quicker, so that delays you catching up even more.

[jetdriven]

A couple knots here, a couple knots there, pretty soon it adds up.

We whipped and drove our plane to get to OSH this year. Flew the whole way from Houston at full throttle 2500 RPM and 2500' to FISKE.  got there at 1PM. my other friend flew at his standard 6500', 25 squared whatever setting and arrived just after the arrivals closed. They went to Fond DuLac.

[gsengle]

For the early Ovation that is *not* a short field performer, the Harzell was a great improvement in takeoff and climb over the original 3 blade McCauley. Honestly think I picked up a knot or three in cruise but harder to tell...

But sure looks cool




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[MyNameIsNobody]

1 hour ago, jetdriven said:

A couple knots here, a couple knots there, pretty soon it adds up.

We whipped and drove our plane to get to OSH this year. Flew the whole way from Houston at full throttle 2500 RPM and 2500' to FISKE.  got there at 1PM. my other friend flew at his standard 6500', 25 squared whatever setting and arrived just after the arrivals closed. They went to Fond DuLac.

What fuel flow?  Just curious, no dark intent...

[jetdriven]

10.5 GPH 160 ktas 

[testwest]

I would have to drag out my Benchmark models and have a look at the differences....KSMooniac’s prop takes a lot of weight off the nose, meaning less trim drag. Jetdriven has done a huge aerodynamic cleanup includes 80+ hours of wing profiling on his and I think the standard prop...Byron?

So there are many trade offs and the answer is not perfectly obvious. 

What would be nice is a 2 blade composite prop for our airplanes like the Hartzell ASC II used on the Diamond DA-40 XL. 46.8 lbs. By contrast the Hartzell BA prop we have on our J weighs 64 lb. The cost for the STC, well......I wonder if Hartzell made their forward-loss money back on the BA Top Prop program. There were certainly a lot of spinner problems early on.

The tip profile starts to make a difference when it is really cold, as the tip Mach number goes up the drag advantage on the very narrow-chord thin tip profiles of the modern blades starts to be significant. 

 

[xcrmckenna]

I would have to drag out my Benchmark models and have a look at the differences....KSMooniac’s prop takes a lot of weight off the nose, meaning less trim drag. Jetdriven has done a huge aerodynamic cleanup includes 80+ hours of wing profiling on his and I think the standard prop...Byron?
So there are many trade offs and the answer is not perfectly obvious. 
What would be nice is a 2 blade composite prop for our airplanes like the Hartzell ASC II used on the Diamond DA-40 XL. 46.8 lbs. By contrast the Hartzell BA prop we have on our J weighs 64 lb. The cost for the STC, well......I wonder if Hartzell made their forward-loss money back on the BA Top Prop program. There were certainly a lot of spinner problems early on.
The tip profile starts to make a difference when it is really cold, as the tip Mach number goes up the drag advantage on the very narrow-chord thin tip profiles of the modern blades starts to be significant. 
 

I really wish MT would stc a two blade prop for the 201...


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[Andy95W]

I would volunteer my M20C for testing if they did...