2 Blade Prop Quicker?

[scottfromiowa]

Why is it that those with two blade props go on and on and on about a couple of knots of speed loss (three blade vs. two) and continue to state over and over and over that it must be ramp appeal?  I 100% DO like my prop AND the polished spinner over ANY two blade prop.  I fly LOP and my plane is plenty fast, climbs great and I have no useful load issues for my flying so keep your two blades your useful load and your two knots...I'll take my three blade, thank you very much.  Prop envy it's a terrible thing of which I am NOT afflicted.

[Newmooneyguy]

It's been a lively discussion.  I would say the topic has been covered thoroughly by a panel of intelligent experts.

[gregwatts]

Quote: scottfromiowa

Why is it that those with two blade props go on and on and on about a couple of knots of speed loss (three blade vs. two) and continue to state over and over and over that it must be ramp appeal? I 100% DO like my prop AND the polished spinner over ANY two blade prop. I fly LOP and my plane is plenty fast, climbs great and I have no useful load issues for my flying so keep your two blades your useful load and your two knots...I'll take my three blade, thank you very much. Prop envy it's a terrible thing of which I am NOT afflicted.

[scottfromiowa]

Quote: gregwatts

 

 

Don't hate.........!

[Jsavage3]

2-blade quicker in cruise...so it is.  Anyone care to expound on WHICH 2-blade is faster in cruise?  McCauley or Hartzell?

 

I witnessed a scimitar Hartzell give a C-model 5+ knots over its McCauley and it (Hartzell) was v-e-r-y smooth...  

 

Yes, I flew it before and after the prop swap...

[jetdriven]

According to popular rumor, and Testwest, the BA Hartzell is worth 2-3 knots over the McCauley C214.

[Alan Fox]

I switched from a Macauley 2 blade , to a hartzell 3 blade , Granted it was on my Beech , but this is what I found.....No real discernible difference in cruise , Different feel that took a good month to get used to..Little bit of increased climb performance....  The Main reason I switched , was my Macauley gave up the Red dye , and I didn't want to sink 2K into resealing a 40 year old prop , I bought a 5 year old (new in 07) prop for 3500 , Doing the math , after I sold the old prop for 1000 and figuring 2000 for a reseal , it was a no brainer to upgrade , One thing that I have not seen is this.... IT TAKES LESS RUNWAY TO GET AIRBORNE........   I think that the cruise difference is less pronounced with 300 HP verses 180 HP...

[Oscar Avalle]

Has anybody switched from a 3 blade prop to a 2 blade prop? Any speed increase noted?

 

Not again...

[Bob_Belville]

I have a Hartzell  HC-C2YR-1BFP/F7497 Simitar 2 blade prop with no AD to comply with and 16 year old O&N bladders, that have never leaked, on my E. I've been running LOP recently @ 8.6 gph.

 

I have nothing to add to this thread but I was afraid it might die... 

[fantom]

.....It took me 7 years of fairly devoted study to reach that simple conclusion.

By bladders are only 5 years old, though.

Jim

So you have two more years to 'reach the simple conclusion' that you made an error installing condoms in your wings

[carusoam]

Anybody get the four-blade composite one yet?

Few people in the long body crowd want the two-blade option.

More rpm and Scimitar TopProp takes best performance category!

2700rpm is loud with any prop...

Best regards,

-a-

[1964-M20E]

Quicker or not how is it on sound?  I heard that the 3 blades are less noisy.  3 pulses insted of 2

[Alan Fox]

The 3 blade is considerably more quiet... 

[scottfromiowa]

I'm with you, Bob.  Between 8 and 8.6 GPH LOP (roughly 60 to 65 percent power) is a very good place to run our IO-360s at my typically moderate cruise altitudes.  It took me 7 years of fairly devoted study to reach that simple conclusion.

 

By bladders are only 5 years old, though. 

 

Jim 

What is your RPM and altitude to get that fuel flow LOP?  Are you 20, 30,40 50 or more LOP?  I wish to experiement. 

[scottfromiowa]

Thanks in advance for your reply Jim

[Alan Fox]

I am glad I switched , dont really care about "appeal"

[TWinter]

Cody Stallings here on the on the forum works at a prop shop in Arkansas. I saw him at the shop one day and I asked was the three blade better or worse than the two blade for my E (IMHO the three blade does have a cool factor), but performance wise he said stay with the two blade. Just a pass on of info told to me. No tech info from me to back it up. I'm sure he will chime in sometime today. 

[scottfromiowa]

If performance is only speed I could not agree more.  If performance is climb, ground roll as well as speed then there is a debate.  I take exception to the ramp appeal and wish it would be removed from the equation...The weight is another performance factor to evaluate in your decision as well as the cost to overhaul/maintain.  If I had a two blade I would not change it.  I had a 3-blade prop hanging on my plane when I bought it.  I like the three blade A LOT and would NOT change on my plane, but if I came into money and bought my...Missile.  it would already have a three-blade.  No worries.

 

Jim-The reason I asked on degree LOP is that I can not get that fuel flow down lower without running rough.  Have not been able to get high enough (weather) to go that low.  I generally would rather be Peak to 50LOP and burn 9.5 to 10GPH and get the extra speed.  I feel THAT is the "sweet spot" for engine/fuel flow/speed return on the IO-360.  Different strokes for different folks, but when I want to slow down I will try rolling back to 8.5 up higher and see how it feels and what Ground Speed is telling me...and at what %LOP I am.  My G3 tells me what % ROP or LOP each cylinder is with color and numeric display.  I have it set for 50LOP.

[scottfromiowa]

Well Jim, probably NOT true as I could just pull power more to get to 8.5...Just so focused on LOP and speed variable I have not pulled power (at least down lower 2000-4000) to see how it feels.  Usually trying to cover ground...

[eaglebkh]

Have a race climbing to 10,000'  - who is quicker (3-blade or 2)?

Have a race to cover 500nm - who is quicker?

[jetdriven]

Well Jim, probably NOT true as I could just pull power more to get to 8.5...Just so focused on LOP and speed variable I have not pulled power (at least down lower 2000-4000) to see how it feels.  Usually trying to cover ground...

 

I am like Jim, I don't get too wrapped around the axle. When trying to get there without wasting gas or airplane time, I pull mixture to 10.0 GPH below 3000' DA, and above that lean to 15 LOP.   If below 23" of manifold pressure (due to altitude limitations), I lean to peak EGT and lean further only limited by CHT.  If operating below 55% power, peak EGT, perhaps a few degrees on the rich side.  LOP ops at high altitude aren't necessarily more efficient.

 

Lycoming authorizes operations AT peak EGT at 75% power and below, but you can only do 75% on cool days in our plane.

[FlyDave]

Here is an interesting article on 2 vs. 3 blade props.

I looks like it was written by Aviation Consumer based on the links at the bottom of the page but this link not on the Aviation Consumer site:

 

http://www.moonflight.org/Documents/3-Blade.htm

[scottfromiowa]

I am like Jim, I don't get too wrapped around the axle. When trying to get there without wasting gas or airplane time, I pull mixture to 10.0 GPH below 3000' DA, and above that lean to 15 LOP.   If below 23" of manifold pressure (due to altitude limitations), I lean to peak EGT and lean further only limited by CHT.  If operating below 55% power, peak EGT, perhaps a few degrees on the rich side.  LOP ops at high altitude aren't necessarily more efficient.

 

Lycoming authorizes operations AT peak EGT at 75% power and below, but you can only do 75% on cool days in our plane.

Aren't you like me? Jim has an 8.5gph fuel flow. I am also pulling to 9.5gph-10.0 below 3,000. I will be in red box if I go fuel throttle, so pull to 25MP or lower. My G3 says below 75% or below at that number. What fuel flow do you normally fly down low if NOT wasting gas? I never go over 10GPH...Didn't seem like much speed increase vs. fuel flow.

[Jsavage3]

Anyone care to comment on which 2-blade is better (faster in cruise)...Hartzell simitar or the McCauley?

[jetdriven]

after flying a Hartzell BA prop, it does behave quite differently. For one thing,  it takes 2000 RPM for me to fly a normal base and final, I have  McCauley  C214. .  The BA won't descend with that setting. It takes 1400 RPM or less to get down.  It produces much more thrust. That prop is wonderful.