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I was in ABE(Allentown, PA) last week. While there, I saw a Piper Navaho with the prop blades bent 90 degrees about 4" back. I'm guessing it has to do with preventing the tips from exceeding the speed of sound.

2007-06-11 20:05:39 · 9 answers · asked by Anonymous in Cars & Transportation Aircraft

9 answers

They are called "Q-tip" props.

Prop manufacturer Hartzell says there are two advantages:

One is that the propellers' normal diameters are reduced by one inch. This keeps dirt and small stones farther from the blade tips, and keeps tip erosion during ground operations to a minimum.

Two is noise reduction. The curl of the Q-tip acts much like a winglet, smoothing out the vortices — and therefore the noise — caused by low-pressure air moving to high as the propeller tips reach the supersonic speeds of high power settings.

2007-06-11 22:41:49 · answer #1 · answered by Av8trxx 6 · 3 0

Hartzell Q Tip Propeller

2017-01-13 06:22:34 · answer #2 · answered by Anonymous · 0 0

Q tip props act as little "winglets" on the end of the propeller and reduce propeller tip vorticies and therefore make the propeller more efficient by reducing induced drag in the creation of thrust by the propeller "airfoil". They also help reduce noise and may help keep the propeller tips subsonic by decreasing the length of the propeller. Research what the manufacturer has to brag about this prop design. It should be informative, if not at least interesting.

2007-06-14 23:34:00 · answer #3 · answered by Tim W 2 · 0 0

I would be guessing the prop has had a ground strike which has bent the blades as you describe.
We do need to keep tip speed below sonic, but this is done through prop design, reduction gearboxes etc.

MHS - I think you need to look at the aerodynamic differences between a wing and a propeller blade.

MHS - Maybe I owe you an apology - to be honest I have never heard of "Q Tip" props.
I am so used to the real props as fitted to the P3 Orion.
I need to read a lot more - but being retired , I don't get the time.

2007-06-11 20:15:14 · answer #4 · answered by skytrain18 3 · 0 5

Interesting !! My only experience was with the SH-60B/F Seahawk which had rotor blades tips that swept back about 40 degrees... that was to bleed off the air at the tips to reduce sound (the slap)... and to increase rotor efficiency.

I guess I'll have to research to find a pic of what you're describing... and these "Q-tips" (which I've seen on prototype helicopters.

2007-06-12 03:08:21 · answer #5 · answered by mariner31 7 · 0 1

Most modern aircraft nowadays are equipped with winglets. They are basically small vertical fins attached to the end of the wings. They prevent high pressure air from the underside of the wing to flow to the low pressure side on top of the wing. Hereby they prevent (to a certain extend) the formation of tip vortices that would normally generate extra drag.

I can imagine that fitting a propellor with 'winglets' has the same effect. The propellor blades have less drag and hence it becomes easier to spin them around.

2007-06-11 20:54:21 · answer #6 · answered by MHS 1 · 0 2

I agree with Tim W above. They reduce wing-tip vortices, channeling more of the thrust air backwards, instead of outwards. Ergo, more efficient power transfer from engine to thrust, with less noise.

Mel G. I am a Cdn. A.M.E. Cat.1,2.

2015-05-18 14:08:09 · answer #7 · answered by Mel 1 · 0 0

Q-tips. Increase lift without increasing length by decreasing the tip vorticies. and yes they are also quieter. (and make a neat whistle sound when they spool down)

2007-06-14 15:55:00 · answer #8 · answered by Bill and Gin C 2 · 0 0

Those are Q-tip props for noise abatement.

2007-06-12 03:47:42 · answer #9 · answered by thresher 7 · 1 0

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