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Vx, Vy, Best Glide for O-360/Hartzell

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czechsix(at)juno.com
Guest

Posted: Mon Apr 24, 2006 5:48 pm Post subject: Vx, Vy, Best Glide for O-360/Hartzell

Guys,

I'm getting ready to do performance testing for Vx, Vy, and best glide speeds in my RV-8A with O-360/Hartzell setup.  I know there are some POH's floating around out there with these numbers in them but I'm curious how many people have measured this data carefully themselves?  In particular to get good glide data one would have to pull the mixture and ideally test with the prop stopped, prop rotating with oil pressure & lever aft, and prop rotating without oil pressure (fine pitch).  This could take quite a few engine-off glide tests and the numbers should be pretty close from one RV to the next...

Which brings me to my point: if there's any "consensus" on these speeds amongst those of you who've taken good data it would be nice to have those numbers as a starting point for my testing.  For example if Vy is typically 80-90 kts I would narrow the range of my test from 75 to 95 instead of a much broader span of numbers.

It would be cool if someone made a spreadsheet collecting this kind of data from different airplanes.  Checkoway are you listening?

Thanks,

--Mark Navratil

Cedar Rapids, Iowa

RV-8A N2D flying 29.2 hours now...



Guys,





I'm getting ready to do performance testing for Vx, Vy, and best glide speeds in my RV-8A with O-360/Hartzell setup. I know there are some POH's floating around out there with these numbers in them but I'm curious how many people have measured this data carefully themselves? In particular to get good glide data one would have to pull the mixture and ideally test with the prop stopped, prop rotating with oil pressure  lever aft, and prop rotating without oil pressure (fine pitch). This could take quite a few engine-off glide tests and the numbers should be pretty close from one RV to the next...





Which brings me to my point: if there's any "consensus" on these speeds amongst those of you who've taken good data it would be nice to have those numbers as a starting point for my testing. For example if Vy is typically 80-90 kts I would narrow the range of my test from 75 to 95 instead of a much broader span of numbers.





It would be cool if someone made a spreadsheet collecting this kind of data from different airplanes. Checkoway are you listening?





Thanks,





--Mark Navratil

Cedar Rapids, Iowa

RV-8A N2D flying 29.2 hours now...

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randy(at)romeolima.com
Guest

Posted: Tue Apr 25, 2006 2:22 pm Post subject: Vx, Vy, Best Glide for O-360/Hartzell

 	  Quote: 	
		   I'm getting ready to do performance testing for Vx, Vy, and best glide 

 speeds in my RV-8A with O-360/Hartzell setup.  I know there are some POH's 

 floating around out there with these numbers in them but I'm curious how 

 many people have measured this data carefully themselves?  In particular 

 to get good glide data one would have to pull the mixture and ideally test 

 with the prop stopped, prop rotating with oil pressure & lever aft, and 

 prop rotating without oil pressure (fine pitch).  This could take quite a 

 few engine-off glide tests and the numbers should be pretty close from one 

 RV to the next...

 Which brings me to my point: if there's any "consensus" on these speeds 

 amongst those of you who've taken good data it would be nice to have those 

 numbers as a starting point for my testing.  For example if Vy is 

 typically 80-90 kts I would narrow the range of my test from 75 to 95 

 instead of a much broader span of numbers.

 It would be cool if someone made a spreadsheet collecting this kind of 

 data from different airplanes.  Checkoway are you listening?

 Thanks,

 --Mark Navratil

 Cedar Rapids, Iowa

 RV-8A N2D flying 29.2 hours now...


	


Mark, I did quite a bit of testing for Vy in my RV-8 in the course of doing 

prop climb rate testing. Interestingly I found a slightly different Vy for 

each prop, but if you stay within the 115-125 mph (99-107 kts) range you 

will find your number. 120-122 mph (103-105 kts) was the sweet spot so be 

sure and check there.



I always meant to check my glide with the prop turning and with it not, but 

never did.



Randy Lervold

www.rv-3.com

www.rv-8.com

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Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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