One Bladed Props

[Stevo]

Re: One Bladed Props

...Pretty sure I see the othe half of the prop behind that funny looking spinner.
Tom

Shouldn't that be "IN FRONT of that funny looking spinner"?

[First time Juke]

Re: One Bladed Props

I am confused.

I myself tought about less props being more efficient and dudes in Finland say Hartzell says more props is more efficient ?

Who is right ?

For my small racer I have been thinking a two blader and a Merlin engine.
I figure I have better efficiency and less weight possibly..and torque...if the two blader has less area and pushes the pressure on thinner part of the wing where there is less drag.

[jarrodeu]

Re: One Bladed Props

Interesting point. They are now installing props with 6 blades on C-130J's. I heard to make it more efficient.

http://ascpa.public.wpafb.af.mil/Images/News/C130J.jpg

Jarrod

[Peashooter]

Re: One Bladed Props

What am I missing here? Pretty sure I see the othe half of the prop behind that funny looking spinner.
Tom

It's a 2-bladed prop. The point was that it's like a scaled-up APC prop planform.

[morss]

Re: One Bladed Props

Interesting point. They are now installing props with 6 blades on C-130J's. I heard to make it more efficient.

http://ascpa.public.wpafb.af.mil/Images/News/C130J.jpg

Jarrod

are those props or un ducted fans?
dave

[Tin Man]

Re: One Bladed Props

It's a 2-bladed prop. The point was that it's like a scaled-up APC prop planform.

Now I get it.
Is that Gary Hertzlers airplane? Last time I saw his it was a lot cleaner than that.
Tom

[laminar]

Re: One Bladed Props

Please correct me if I am wrong but my understanding is such

For the given horsepower of the engine one has a sliding scale interms of how they will go about "throwing back air" in order to move themselves forward. On one end of the scale is moving a very large cross section of air to a very slow speed (standard two bladed prop) or on the other end of the spectrum one can move a much smaller crossection of air to a very high velocity (jet engine w/o bypass fan). This is the reason puddle jumpers with turbo props can take off so short but cant cruise as fast as the jets (like say an f-16). And this is also why the ME-262 with no after burner was such a runway hog on take off.

This is why Jet airliners run high bypass fans. It is the blend of the two technologies. or your six bladed c-130.

So if one is try to build a slow flight R/c airplane one say for STOL charecteristics one should build a one bladed prop with a very long shallow pitched blade. Therefore moving the largest crossection of air to the slowest speed possible (cruise between 15-25mph) while also cutting down on the weight in the prop and hopefully getting higher revs out of the motor.

Problem is I know there has got to be art to he building of these props and I would like to pay an artist for his knowledge by buying a prop from them, where do I find this artist?

[Skyracer]

Re: One Bladed Props

Somewhere back in aviation history there was the Everel single blade prop. I saw a J3 (or Champ) fly with one several years ago at the NWAAC flyin at Evergreen Field, Vancouver WA and am pretty sure I have a picture of it somewhere (don't expect me to find it in this decade).

The Everel prop was noted as more efficient than conventional two bladed props and reportedly a J3 had a shorter takeoff roll, better climb rate, and cruised 5-10 MPH faster with the Everel prop. Part of the secret to this efficiency was that the prop was more than just a carved stick with a counterweight on the other end. The blade was mounted to a gimbal setup and as the load or "pull" on the prop changed the blade actually changed pitch in flight.

I did a quick internet search but did not find any good information abut the Everel prop.

[Air Race Addict]

Re: One Bladed Props

are those props or un ducted fans?
dave

Are you being, gulp, big word for the day, FACECIOUS, Dave?

Just for more info on the 6 bladed 13' 6" prop. We use one, (two actually ) Dowty composite 13' 6" props on our Q400's. The aircraft has 5k Hp P&W a side. Hauls butt! Literally It is VERY fuel efficient, and it goes reeeeel fast, faster than the 200 by 100kts or more. Prop RPM is quite similar to the Q200 (Ham Standard 4 blade 13' prop, 2100 Hp P&W), in T/O, climb, and cruise (1020, 950, 850, although the Q200 Np runs a little higher). I'll attach a pic below. (These are DeHavilland Dash 8's in case anyone was wondering). Q400 carries 74, Q200 - 37. Why not put one of those props on Furias or the Buick and see how fast she'll really go Crank up the Hp!

[Apteryx]

Re: One Bladed Props

Somewhere back in aviation history there was the Everel single blade prop. I saw a J3 (or Champ) fly with one several years ago at the NWAAC flyin at Evergreen Field, Vancouver WA and am pretty sure I have a picture of it somewhere (don't expect me to find it in this decade).

Picture HERE on a T-craft.

Paul

[Unregistered]

Re: One Bladed Props

I have flown control line speed and racing for years. Single blade props work and work well but remember the size. A 2.5 single blade prop is less than 5 inches long, made from carbon fiber they way nothing. The advantage I saw was greater slip at slow speed allowing the engine to rev high enough to catch the pipe. Pipes rarely come on under 32.000 rpm and work well to over 40,000 rpm. Not everything that works in models works in real airplanes. Assyametric airplanes come from going fast on a wire.

[Unregistered]

Re: One Bladed Props

For many years we have had a Everel Single Blade prop on display above our fireplace. Just where my late father got this thing, I'll never know. Mom says that Dad did, just once, fly a Champ with the prop mounted up front.

sd
natairace@aol.com

[Wes]

Re: One Bladed Props

I found this in an old Air Progress Magazine-Home Built Aircraft (Spring Summer of 1967) It was under Mr. Everts' One Bladed Wonder. It says "Chop off one blade and increase speed by 25%? Up your rate of climb by 30%? Cut your takeoff run by 50%?...". Looks like an Everel propeller developed by Walter W. Everts of Baltimore, Md. He used a counter weight to substantially reduce engine vibration. "Connected as it was to the engine by means of trunnions,(A self-contained fully Automatic Variable Pitch Prop) the blade and counterweight assembly actually functioned as an effective damper. However, the Everel was to be on the market for only a short time. The advent of 50-hp engines in 1938 afforded the desired boost in performance at less cost and mechanical complexity." It was apparently quite expensive and it required frequent rebalancing due to releasing of moisture with weather changes. "Everts later sold his patent (No. 2,071,513) to the Koppers Company,..."

[fenceliner01]

Re: One Bladed Props

THIS ONE ?

Koyaanisqatsi

paul - lets hope it wasn't Koyaanusqatsi. The counterwight should take care of that. but what about the asymmetrical thrust on the prop shaft?

[sierra fox]

Re: One Bladed Props

THIS ONE ?

Koyaanisqatsi

......"prop" out of balance?
......"prop" in termoil?
......"prop" that needs another way of turning?