2 blade vs. 3 blade props

meritflyer · October 17th, 2009, 11:42

There seems to be a very distinct crowd in the CFI/owner/GA community regarding 2 blade vs. 3 blade props.

I sat with a group of novice CFIs and plane owners recently and watched them have it out. It was comical to say the least.

The 2 blade crowd says that they can get climb rates as good as the 3 blade crowd but get better speeds in cruise.

The 3 blade crowd says they get better hole shots (faster acceleration on takeoff), better climb rates, and comparable cruise speeds.

There are apparently some new, very advanced 2 blades that have come out. Aerodynamically, I've always thought the two are comparable.

wjmiller3 · October 17th, 2009, 11:50

If a little is good, a lot MUST be better!!! I always thought these looked cool:

Cptnchia · October 17th, 2009, 11:57

Why do I have a two bladed prop on my plane?

Because it came that way from the manufacturer. If it was good enough for them to put it on the plane back in 1947, why mess with it now.

esa17 · October 17th, 2009, 12:18

Three blades are much smoother and give you a touch better climb. Three blade scimitars are the cats-arse since they are so quiet. Sure, you lose a knot or two at cruise because of the extra blade but the real benefit is the ride.

Roger, Roger · October 17th, 2009, 14:12

A Cessna 185 with the 2-bladed prop is ungodly loud for a piston single running only 6 cylinders. The 3 blade is a lot quieter, and therefore not as cool.

Jbroz04 · October 17th, 2009, 14:16

We have two 182rgs. One with two blade prop. One with a three blade. The difference ???? Fly the same to me. The only difference is one has electric trim on the yoke which is wonderful.

Minuteman · October 17th, 2009, 14:34

On airplanes with a choice between two or three-bladed props, does the engine make the same amount of power? Does the tachometer's green arc have the same boundaries?

KSCessnaDriver · October 17th, 2009, 15:23

Quote:

Originally Posted by Minuteman

On airplanes with a choice between two or three-bladed props, does the engine make the same amount of power? Does the tachometer's green arc have the same boundaries?

When the DA-40 in my avatar went from the 3-blade wood-composite prop to the 2 blade metal scimitar, nothing changed on the tach (G1000), as far as I know. The only difference before versus after was a slight reduction in climb speed and a fairly decent increase in cruise speed (went from 130ish KTAS to close to 140 KTAS).

Orange Anchor · October 17th, 2009, 17:48

The Russians have liked many blades and counter-rotating props for a long time. AN-70

stratoduck · October 17th, 2009, 18:39

Is it worth bringing up the single bladed prop for the Continental 65? It was counterweighted and allowed a slight rotation that gave it a small change in pitch. It claimed to climb and cruise better than the two bladed props of the time. My grandfather met a guy back in the 1940's with one on a Taylorcraft that substantiated the manufacturer's claims. The only thing I've ever found concerning this prop are old ads. Seems to have completely disappeared from aviation rather quickly. I would love to hear if anyone knows of what happened to the product.

Blackhawk · October 18th, 2009, 01:10

Three bladed MTV-9 prop eliminates the 2000-2350 RPM limit on the 8KCAB.

ProudPilot · October 18th, 2009, 03:17

Quote:

Originally Posted by stratoduck

Is it worth bringing up the single bladed prop for the Continental 65? It was counterweighted and allowed a slight rotation that gave it a small change in pitch. It claimed to climb and cruise better than the two bladed props of the time. My grandfather met a guy back in the 1940's with one on a Taylorcraft that substantiated the manufacturer's claims. The only thing I've ever found concerning this prop are old ads. Seems to have completely disappeared from aviation rather quickly. I would love to hear if anyone knows of what happened to the product.

Oh I'd love to see a picture.

Blackhawk · October 18th, 2009, 10:24

Quote:

Originally Posted by ProudPilot

Oh I'd love to see a picture.

http://www.ultraligero.net/Cursos/va...e_una_pala.pdf

K-Train · October 29th, 2009, 21:34

Quote:

Originally Posted by Roger, Roger

A Cessna 185 with the 2-bladed prop is ungodly loud for a piston single running only 6 cylinders. The 3 blade is a lot quieter, and therefore not as cool.

Baronman · October 30th, 2009, 10:18

I thought 2 bladed props give higher cruise speeds but are generally louder than 3 bladed props.

At Flight Safety we had a fleet of Senecas with 3 bladed props, and only one aircraft with a two bladed prop......The 2 blade airplane cruised about 5-10 kts faster, even flying together once the guy in the 2 blade prop passed me easily.

tlewis95 · October 30th, 2009, 14:41

I have always liked the single blade idea. It is very popular on the Silent self-launch sailplane series here that are in production currently.

OhioStatePilot · October 30th, 2009, 18:00

Just from looking at the single blade idea, I know they use counterweights to dampen vibration, but wouldn't the fact that lift is only created on one side of the hub create serious wear concerns for the prop shaft/bearings?

October 17th, 2009, 11:42	#1
meritflyer Old Skool Join Date: Dec 2005 Location: Winchestertonfieldville Posts: 7,427	2 blade vs. 3 blade props There seems to be a very distinct crowd in the CFI/owner/GA community regarding 2 blade vs. 3 blade props. I sat with a group of novice CFIs and plane owners recently and watched them have it out. It was comical to say the least. The 2 blade crowd says that they can get climb rates as good as the 3 blade crowd but get better speeds in cruise. The 3 blade crowd says they get better hole shots (faster acceleration on takeoff), better climb rates, and comparable cruise speeds. There are apparently some new, very advanced 2 blades that have come out. Aerodynamically, I've always thought the two are comparable. __________________ The simplest answer tends to be correct.

October 17th, 2009, 11:50	#2
wjmiller3 Senior Member Join Date: Apr 2007 Location: Houston Posts: 549	Re: 2 blade vs. 3 blade props If a little is good, a lot MUST be better!!! I always thought these looked cool:

October 17th, 2009, 11:57	#3
Cptnchia Old Skool Join Date: May 2007 Location: Southern Mecca Posts: 1,574	Re: 2 blade vs. 3 blade props Why do I have a two bladed prop on my plane? Because it came that way from the manufacturer. If it was good enough for them to put it on the plane back in 1947, why mess with it now. __________________ "Chicken's Ready."

October 17th, 2009, 12:18	#4
esa17 Senior Member Join Date: Jul 2007 Location: KTRL, KTYR, F46, T48 Posts: 1,155	Re: 2 blade vs. 3 blade props Three blades are much smoother and give you a touch better climb. Three blade scimitars are the cats-arse since they are so quiet. Sure, you lose a knot or two at cruise because of the extra blade but the real benefit is the ride. __________________ Being captain is about pure intuition and heart, a good captain can't have either one.

October 17th, 2009, 14:12	#5
Roger, Roger Old Skool Join Date: Sep 2008 Location: Lone Star Executive Posts: 2,643	Re: 2 blade vs. 3 blade props A Cessna 185 with the 2-bladed prop is ungodly loud for a piston single running only 6 cylinders. The 3 blade is a lot quieter, and therefore not as cool. __________________ Current A&P. Occasional CFI. Still wannabe Freight Dog.

October 17th, 2009, 14:16	#6
Jbroz04 Senior Member Join Date: Dec 2008 Location: Vermilion Posts: 611	Re: 2 blade vs. 3 blade props We have two 182rgs. One with two blade prop. One with a three blade. The difference ???? Fly the same to me. The only difference is one has electric trim on the yoke which is wonderful. __________________ The last thing every pilot does after a gear up landing is to move the gear selector to down.

October 17th, 2009, 14:34	#7
Minuteman Old Skool Join Date: May 2003 Location: Austin, TX Posts: 2,674 Blog Entries: 1	Re: 2 blade vs. 3 blade props On airplanes with a choice between two or three-bladed props, does the engine make the same amount of power? Does the tachometer's green arc have the same boundaries? __________________ "We are Miracle Whip, and we will not* tone it down!*"

October 17th, 2009, 17:48	#9
Orange Anchor Old Skool Join Date: May 2008 Location: ATL Posts: 1,803	Re: 2 blade vs. 3 blade props The Russians have liked many blades and counter-rotating props for a long time. AN-70 __________________ If you have integrity, nothing else really matters. If you don't have integrity, nothing else really matters.

October 17th, 2009, 18:39	#10
stratoduck Newbie Join Date: Feb 2009 Location: Brooklyn Posts: 15	Re: 2 blade vs. 3 blade props Is it worth bringing up the single bladed prop for the Continental 65? It was counterweighted and allowed a slight rotation that gave it a small change in pitch. It claimed to climb and cruise better than the two bladed props of the time. My grandfather met a guy back in the 1940's with one on a Taylorcraft that substantiated the manufacturer's claims. The only thing I've ever found concerning this prop are old ads. Seems to have completely disappeared from aviation rather quickly. I would love to hear if anyone knows of what happened to the product.

October 18th, 2009, 01:10	#11
Blackhawk Senior Member Join Date: Dec 2006 Location: KELP Posts: 599	Re: 2 blade vs. 3 blade props Three bladed MTV-9 prop eliminates the 2000-2350 RPM limit on the 8KCAB. __________________ "No matter where you go, there you are." "Life is life and fun is fun, but it's all so quiet when the goldfish die." samdawsoncfi.com

October 30th, 2009, 10:18	#15
Baronman Old Skool Join Date: Dec 2001 Location: NEWARK Posts: 1,558	Re: 2 blade vs. 3 blade props I thought 2 bladed props give higher cruise speeds but are generally louder than 3 bladed props. At Flight Safety we had a fleet of Senecas with 3 bladed props, and only one aircraft with a two bladed prop......The 2 blade airplane cruised about 5-10 kts faster, even flying together once the guy in the 2 blade prop passed me easily. __________________ "I got a FEVER, and the only perscription is more Cow-Bell!"

October 30th, 2009, 14:41	#16
tlewis95 Senior Member Join Date: Apr 2008 Location: Carbondale, IL Posts: 1,334	Re: 2 blade vs. 3 blade props I have always liked the single blade idea. It is very popular on the Silent self-launch sailplane series here that are in production currently. __________________ CSEL/G - IR "It's not a hobby, it's a lifestyle"

October 30th, 2009, 18:00	#17
OhioStatePilot Senior Member Join Date: Feb 2009 Location: HSV Posts: 1,301	Re: 2 blade vs. 3 blade props Just from looking at the single blade idea, I know they use counterweights to dampen vibration, but wouldn't the fact that lift is only created on one side of the hub create serious wear concerns for the prop shaft/bearings? __________________ Garrett GO BUCKEYES!

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