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Winglets On Propeller Tips  
User currently offlineczbbflier From Canada, joined Jul 2006, 975 posts, RR: 2
Posted (1 year 6 months 2 weeks 5 days 14 hours ago) and read 6066 times:

I was just perusing the thread asking about the possibility of 90-seat turboprops and admiring the image of an ATR aircraft that had winglets and 8 bladed propellers.

The aircraft had winglets on the wing and it looked odd enough that it made me stop and think- would putting small winglets on the propeller tips achieve the same result?

I imagine that the tips are more like points and that they are swept back to minimize the vortex and shockwave but would bending the tips into actual winglets at say, a 30-degree angle, make them more efficient?

With propeller tips pointing toward the forward end of the plane it would look really odd but would it work?

Any aerodynamicists out there?

Cheers!
Brian



10 replies: All unread, jump to last
 
User currently offlinevzlet From United States of America, joined Mar 2004, 838 posts, RR: 0
Reply 1, posted (1 year 6 months 2 weeks 5 days 12 hours ago) and read 5879 times:

Google "q-tip propeller". They've been in use for a while, usually as refitted upgrades.

(Even on blimps.)
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"That's so stupid! If they're so secret, why are they out where everyone can see them?" - my kid
User currently offlinePihero From France, joined Jan 2005, 4585 posts, RR: 77
Reply 2, posted (1 year 6 months 2 weeks 5 days 12 hours ago) and read 5879 times:
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First, a propeller blade is just an airfoil - like a wing - and the nbasic aerodynamics are no different than a wing .
But the rotation of the blade creates more phenomena than a wing, in particular the helicoidal vortex one sees behind the prop and causes all sorts of * propeller effects*.
In theory, nothing would prevent us from having winglets at the prop tips :
the advantages would be 1/ making the prop more efficient by reducing the induced drag ( sama same as a wing ), 2/ reduce noise, 3/ keep the prop ti subsonic by decreasing its length...
Big problem is in aerodynamic streeses and AFAIK, there had been some quite spectacular failures during testing, so the solution is now to give a greater sweep to the tips ( see that as equivalent to the 777 wing tip compared to the 787 for instance). Try and find articles on the *Hartzell Q-tip*.
As naval propellers are wider and capable of deealing with bigger torque stresses, modern ones do have winglets. You could find some pictures on the web.



Contrail designer
User currently onlinevikkyvik From United States of America, joined Jul 2003, 10095 posts, RR: 26
Reply 3, posted (1 year 6 months 2 weeks 5 days 8 hours ago) and read 5723 times:
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Sometimes pilots decide to add them:


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User currently offlineczbbflier From Canada, joined Jul 2006, 975 posts, RR: 2
Reply 4, posted (1 year 6 months 2 weeks 5 days 2 hours ago) and read 5502 times:

Thanks all! I guess the scimitar props essentially achieve the same thing without the structural issues.

Quoting vikkyvik (Reply 3):
Sometimes pilots decide to add them:

I had to look. Thanks for the chuckle of the day.  


User currently offlineStarlionblue From Greenland, joined Feb 2004, 17068 posts, RR: 66
Reply 5, posted (1 year 6 months 2 weeks 5 days 1 hour ago) and read 5491 times:

Quoting czbbflier (Reply 4):
Thanks all! I guess the scimitar props essentially achieve the same thing without the structural issues.

The equivalent of raked wingtips I suppose.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineKELPkid From United States of America, joined Nov 2005, 6407 posts, RR: 3
Reply 6, posted (1 year 6 months 2 weeks 4 days 23 hours ago) and read 5421 times:

Quoting vzlet (Reply 1):
Google "q-tip propeller". They've been in use for a while, usually as refitted upgrades.

Q-tip props were all the rage on high end piston singles and twins in the 1990's. They used to drive me nuts on the ramp, as it looked as if someone did a low pass down the runway before realizing the gear wasn't down   Don't think I've seen a Q-tip prop in at least a decade...



Celebrating the birth of KELPkidJR on August 5, 2009 :-)
User currently onlineTWA772LR From United States of America, joined Nov 2011, 2183 posts, RR: 1
Reply 7, posted (1 year 6 months 2 weeks 4 days 22 hours ago) and read 5399 times:

http://en.wikipedia.org/wiki/Winglets#Use_on_rotating_blades
They have even been used on wind power farms.  



Go coogs! \n//
User currently offlinevzlet From United States of America, joined Mar 2004, 838 posts, RR: 0
Reply 8, posted (1 year 6 months 2 weeks 4 days 19 hours ago) and read 5319 times:

Quoting KELPkid (Reply 6):
looked as if someone did a low pass down the runway before realizing the gear wasn't down

There was allegedly an incident where an FAA inspector grounded a q-tipped aircraft on a ramp check until the "damaged" props were repaired.



"That's so stupid! If they're so secret, why are they out where everyone can see them?" - my kid
User currently offlineKELPkid From United States of America, joined Nov 2005, 6407 posts, RR: 3
Reply 9, posted (1 year 6 months 2 weeks 4 days 9 hours ago) and read 5130 times:

Quoting vzlet (Reply 8):
There was allegedly an incident where an FAA inspector grounded a q-tipped aircraft on a ramp check until the "damaged" props were repaired.

   I could totally see that happening in real life. Especially with one of the older, crustier inspectors  



Celebrating the birth of KELPkidJR on August 5, 2009 :-)
User currently offlinem1m2 From Canada, joined Dec 2011, 93 posts, RR: 0
Reply 10, posted (1 year 6 months 2 weeks 3 days 12 hours ago) and read 4899 times:

Q-tip props are still used on the Piper Cheyenne III. Well, at least they were 8 years ago when I last worked on one, I'd imagine it's still the same. On the Cheyenne III, they were "bent" toward the rear of the aircraft.

I often thought it looked odd, kinda like a "pilot addition" like someone jokingly suggested earlier. But, it was proven when we had the props sent for overhaul and they came back the same way.

[Edited 2013-04-05 09:49:47]

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