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Partial Flap Takeoffs

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quinn_tom(at)tqiinc.com
Guest

Posted: Thu Sep 02, 2010 3:19 am Post subject: Partial Flap Takeoffs

For the second time in a row the Aviation Consumer mentioned that some Tiger owners use partial flaps (1/3rd) for short field takeoffs in their reviews. The POH never mentions using any setting of flaps during takeoffs. Has anyone or recommend using flaps during takeoff?  

   

Tom Quinn  

       [quote][b]

ArjayS(at)AOL.COM
Guest

Posted: Thu Sep 02, 2010 4:32 am Post subject: Partial Flap Takeoffs

Absolutly.

 Jim Bede tells a story echoed by Roy (Lopresti) about testing the original configuration at a high, hot, wet, short Colorado airport. After three runs without breaking ground they decided to dump in some flaps AFTER they started rolling. That did the trick and the procedure was adopted "outside" of the POH. "Outside" because it does not conform to the FAA certification procedure.

 

 Rj Siegel    CEO/LoPresti Aviation Engineering

 

  	  Quote: 	
		  

 For the second time in a row the Aviation Consumer mentioned that some Tiger owners use partial flaps (1/3rd) for short field takeoffs in their reviews. The POH never mentions using any setting of flaps during takeoffs. Has anyone or recommend using flaps during takeoff?

   

 	


 

   [quote][b]

quinn_tom(at)tqiinc.com
Guest

Posted: Thu Sep 02, 2010 4:36 am Post subject: Partial Flap Takeoffs

RJ,  

     Thanks! Why would the wait until after they start rolling to dump some flaps?  

   

   

Absolutly.

 Jim Bede tells a story echoed by Roy (Lopresti) about testing the original configuration at a high, hot, wet, short Colorado airport. After three runs without breaking ground they decided to dump in some flaps AFTER they started rolling. That did the trick and the procedure was adopted "outside" of the POH. "Outside" because it does not conform to the FAA certification procedure.

 

 Rj Siegel   CEO/LoPresti Aviation Engineering

 

 

   



 For the second time in a row the Aviation Consumer mentioned that some Tiger owners use partial flaps (1/3rd) for short field takeoffs in their reviews. The POH never mentions using any setting of flaps during takeoffs. Has anyone or recommend using flaps during takeoff?

    



 

 

   

       [quote][b]

ArjayS(at)AOL.COM
Guest

Posted: Thu Sep 02, 2010 4:44 am Post subject: Partial Flap Takeoffs

High, hot, humid, rain

 They wanted to use all available thrust to overcome inertia.

 

  	  Quote: 	
		  RJ,

       Thanks! Why would the wait until after they start rolling to dump some flaps?

 	


 

   [quote][b]

n26780(at)cox.net
Guest

Posted: Thu Sep 02, 2010 5:07 am Post subject: Partial Flap Takeoffs

I have operated off of 1800 - 2500 grass strips for the last 20 odd years with my 79 Cheetah.  The strips always have over 100 foot pine trees on each end.

On hot days I use half tanks or less and I put in about 30 degrees of flaps before I start my takeoff roll.  It seems that the flaps reduce the weight on the mains earlier and reduce the tire friction which results in a shorter takeoff run.  I use the same settings on paved runways and the Cheetah gets off the ground much earlier.

 

Jim

 

From: owner-teamgrumman-list-server(at)matronics.com [mailto:owner-teamgrumman-list-server(at)matronics.com] On Behalf Of Tom Quinn

Sent: Thursday, September 02, 2010 7:35 AM

To: teamgrumman-list(at)matronics.com

Subject: RE: Partial Flap Takeoffs

 

RJ,

     Thanks! Why would the wait until after they start rolling to dump some flaps?

 

 

Absolutly.

Jim Bede tells a story echoed by Roy (Lopresti) about testing the original configuration at a high, hot, wet, short Colorado airport. After three runs without breaking ground they decided to dump in some flaps AFTER they started rolling. That did the trick and the procedure was adopted "outside" of the POH. "Outside" because it does not conform to the FAA certification procedure.



Rj Siegel   CEO/LoPresti Aviation Engineering



For the second time in a row the Aviation Consumer mentioned that some Tiger owners use partial flaps (1/3rd) for short field takeoffs in their reviews. The POH never mentions using any setting of flaps during takeoffs. Has anyone or recommend using flaps during takeoff?

 

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flyv35b(at)minetfiber.com
Guest

Posted: Thu Sep 02, 2010 5:12 am Post subject: Partial Flap Takeoffs

"Thanks! Why would the wait until after they start rolling to dump some  flaps?"

  

 Because flaps add drag as well as lift.  And  adding flaps just before rotation speed reduces drag in the early part of the  takeoff roll for supposedly better acceleration, although it may be very small  and not even measurable.

  

 Planes with manual flaps can start the takeoff roll  without flaps and then just at rotation you can pull back on the elevator and  pull up on the flap handle to the first notch and the plane will get off the  ground at a slower speed.  On dirt and grass and snow where the tire  rolling resistance is considerably more than on hard asphalt it is beneficial to  reduce the weight on the tires and get off the ground to reduce the drag  (from the tires) as soon as possible, then accelerate in ground effect and climb  out.

  

 Cliff

 [quote] [b]

allenc3(at)bellsouth.net
Guest

Posted: Thu Sep 02, 2010 6:06 am Post subject: Partial Flap Takeoffs

Almost hate to get into this flap thing, as it is  kind of like arguing over politics or religion, at least on the GG list. That  being said, I routinely use 1/3 flaps on takeoff on my 2600 foot grass strip.  The difference is more than noticeable. On a hot, wet day when the grass is a  little high, a no flap takeoff can make for more excitement than you may want.  1/3 flaps makes it a none event. Don't believe it, come on down and give it a  try.

  

 Claude

  

  



  From: Tom Quinn (quinn_tom(at)tqiinc.com) 

 Sent: Thursday, September 02, 2010 7:16 AM

 To: teamgrumman-list(at)matronics.com (teamgrumman-list(at)matronics.com)  

 Subject: Partial Flap Takeoffs

 



  

For the second time in a  row the Aviation Consumer mentioned that some Tiger owners use partial flaps  (1/3rd) for short field takeoffs in their reviews. The POH never  mentions using any setting of flaps during takeoffs. Has anyone or recommend  using flaps during takeoff? 

  

Tom  Quinn

 	  Quote: 	
		  



href="http://www.matronics.com/Navigator?TeamGrumman-List">http://www.matronics.com/Navigator?TeamGrumman-List

href="http://forums.matronics.com">http://forums.matronics.com

href="http://www.matronics.com/contribution">http://www.matronics.com/c

	




__________ Information from ESET Smart Security,  version of virus signature database 5218 (20100622) __________



The  message was checked by ESET Smart Security.



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      [quote][b]

mmacdonald(at)wi.rr.com
Guest

Posted: Thu Sep 02, 2010 7:13 am Post subject: Partial Flap Takeoffs

While working on my private certificate the flight school's curriculum had us use 1/3 flaps for soft field takeoffs, though the POH dord not state they should be used.

Mark MacDonald

On Sep 2, 2010, at 6:16 AM, "Tom Quinn" <quinn_tom(at)tqiinc.com (quinn_tom(at)tqiinc.com)> wrote:



[quote]    

For the second time in a row the Aviation Consumer mentioned that some Tiger owners use partial flaps (1/3rd) for short field takeoffs in their reviews. The POH never mentions using any setting of flaps during takeoffs. Has anyone or recommend using flaps during takeoff?  

   

Tom Quinn  

        	  Quote: 	
		  

	


[b]

pitts_pilot(at)bellsouth.
Guest

Posted: Thu Sep 02, 2010 7:16 am Post subject: Partial Flap Takeoffs

It doesn't matter much on the AA-1s since the flaps are ...... well,     just there.   

     However, for soft/grass strips, in an airplane that has flaps that     really work ...... I'll keep flaps up until about 10 kts below     flying speed, and then lower full flaps ...... just to take the     weight off as Jim notes.  That allows the best initial acceleration     (less drag from the flaps) and then the shortest runway use.  IMHO,     of course!  YMMV

     Linn

     do not archive

     

     On 9/2/2010 9:06 AM, Jim Fudge wrote:     [quote]                       <![endif]-->   <![endif]-->                

I have operated off of 1800 - 2500 grass strips             for the last 20 odd years with my 79 Cheetah.  The strips             always have over 100 foot pine trees on each end.         

On hot days I use half tanks or less and I put in             about 30 degrees of flaps before I start my takeoff roll.              It seems that the flaps reduce the weight on the mains             earlier and reduce the tire friction which results in a             shorter takeoff run.  I use the same settings on paved             runways and the Cheetah gets off the ground much earlier.         

          

Jim         

                                  

From:                 owner-teamgrumman-list-server(at)matronics.com (owner-teamgrumman-list-server(at)matronics.com)                 [mailto:owner-teamgrumman-list-server(at)matronics.com (owner-teamgrumman-list-server(at)matronics.com)] On                   Behalf Of Tom Quinn

                 Sent: Thursday, September 02, 2010 7:35 AM

                 To: teamgrumman-list(at)matronics.com (teamgrumman-list(at)matronics.com)

                 Subject: RE: Partial Flap                 Takeoffs           

         

         

          

RJ,         

     Thanks! Why             would the wait until after they start rolling to dump some             flaps?         

          

          

Absolutly.

             Jim Bede tells a story echoed by Roy (Lopresti) about             testing the original configuration at a high, hot, wet,             short Colorado airport. After three runs without breaking             ground they decided to dump in some flaps AFTER they started             rolling. That did the trick and the procedure was adopted             "outside" of the POH. "Outside" because it does not conform             to the FAA certification procedure.

             

             Rj Siegel   CEO/LoPresti Aviation Engineering

             

                      



             For the second time in a row the Aviation Consumer mentioned             that some Tiger owners use partial flaps (1/3rd) for short             field takeoffs in their reviews. The POH never mentions             using any setting of flaps during takeoffs. Has anyone or             recommend using flaps during takeoff?

                       



             

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flyv35b(at)minetfiber.com
Guest

Posted: Thu Sep 02, 2010 7:16 am Post subject: Partial Flap Takeoffs

Most manufacturers recommend using flaps for short and  soft field take-offs.  While Grummans do not have Fowler type flaps, which  are much more effective at increasing lift, I personally think that using flaps  on a Grumman on unimproved strips is beneficial.  I would question the 30  degrees that you mention as I think that the drag is probably excessive at that  amount and that lift does not increase beyond a certain lesser angle.   Typically this optimum lift angle is somewhere around the same position as where  the aileron is at full deflection.  On a Grumman this may be a little as 10  degrees, while on planes with Fowler flaps many manufacturers seem to say that  20 degrees is about the maximum or optimum.  The Cheetah and Tiger have a  maximum flap travel of 45 degrees and I personally would not use more than 1/3  flaps or 15 degrees for any situation.  Since the POH does not recommend  using flaps any use puts us in an experimental category mode and only  a lot of carefully controlled testing would show where the optimum flap position  might be for these out of the ordinary situations.  

  

 It would be interesting to see curves of wing lift and  drag coefficients versus angle of attack for various flap settings for the  Grumman wing.  That would tell the story.

  

 Cliff

 [quote]   ---

bob.hodo(at)YAHOO.COM
Guest

Posted: Thu Sep 02, 2010 7:17 am Post subject: Partial Flap Takeoffs

I can think of two reasons to wait before putting in 7.5 to 10 degrees of flaps, but both are negligible.



1)  They won't be adding drag before the extra lift is needed.  (But they don't add much drag anyway at those settings.

2)  Debris is never kicked up off the runway more aggressively than when the engine is operated at max power... i.e. takeoff.  Even though the exposure from the bottom side of the flap is only slightly more towards the perpendicular, it does offer a little bit more opportunity for a small rock to strike the skin down there.



Last winter I landed at Hardwick Field in Cleveland Tn.  A snow a couple days earlier had caused them to put salt on the runway.  (Never saw that before.)  On take-off, the first 1000 feet or so was relatively clean from other prop blasts, but the further down field  you went the more salt there was.



I opted to roll in "some" flaps just prior to rotation, 48 to 50 knots, maybe.  I was surprised at how effective this was at making the cheetah just hop off the ground.



IIRC our aileron stops allow for 7.5 deg down and 15 deg up.  It is quite simple to peg the yoke to the right stop and look out at the left flap and lower it until it's trailing edge matches the aileron deflection, just so that you know what 7.5 deg looks like.



Bob Hodo

GADsden, AL



         [quote][b]

teamgrumman(at)YAHOO.COM
Guest

Posted: Thu Sep 02, 2010 10:09 am Post subject: Partial Flap Takeoffs

I flew out of Lancaster, CA for 22 years . . . .  in all sorts of wind, heat, wind, cold, heat, oh, and did I mention, wind.  Fox field has a very long runway to accommodate fire tankers.  I bought my first Cheetah in 1984.  It had a very tired engine.  It's a good place to practice stuff.  Stuff like different baffles, cowlings, flap settings, aileron settings.  But, I'm getting ahead of myself.

North of Lancaster is a little shit-hole of a town called Rosamond.  The, quote, "Fly-in community" in Rosamond has a pretty short runway (anyone interested in a hangar home, in a shitty little town on the desert, complete with 60 mph winds, for $400,000?  A similar home in Alta Sierra just 10 miles north of Auburn is  $400,000.  Oh, wait, they are the same.).  Sometime around 1987-88, I remember watching a Comanche take-off from Rosamond using flaps.  I decided to give it a go.  Since I couldn't tell how much flap he used, I put in all the flaps.  About halfway down the runway, I knew I wasn't going anywhere.  So, taxi back.  This time, 1/2 flaps.  I got off the ground, but just barely.  After that, I fooled around with taking off using flaps down at various settings.  And when I say fooled around, I mean just that.  What a great way to waste a weekend . . .  or many.  I made a tape strip and attached it to my flap so I could figure out what flaps I was using without relying on that thing in the console.  Through 1991, I tracked the effects on many different flap take-off positions.  After a while, I got to know how this particular plane behaved during takeoff at different flap settings.   

Couple of things:  At 1/3 flaps or more  (i.e., greater than 15 degrees flap deflection), the angle of attack is such that the flow over the top of the flap is no longer attached.  If you can keep the nose way down and go really fast, 1/3 flaps works OK.  If LoPresti dropped in 1/3 flaps at rotational speed, that would have worked fine.  By then, the airflow over the wing is pretty well established and the plane wants to fly anyway.

Any flap deflection over 5 degrees ( and less than 15 degrees) pays off in additional lift.  Up to 10 degrees flap deflection during the take-off roll has little or no effect on time to accelerate to take-off speed.  Greater than 10 degrees and less than 15 degrees, it does begin to hurt the time to accelerate but not by much.  Full aileron deflection is supposed to be around 7.5 degrees.  (though I have seen as little as 5  and as much as 10 degrees).

Bottom line:  any flap setting where the flap is just at the full deflection of the aileron (or slightly over) will get the plane off the ground earlier without hurting the take-off roll.  Ya gots ta remember ta retrack the flaps once you start picking up speed.  

Anyone know John Coze?  I flew with him a few weeks ago.   He has a 6-cylinder Tiger.  And it's heavy.  1685# empty weight.  He carries a 40 lb tool bag on his hat shelf.  The bracket he uses to hold the tools in place probably weighs 5 lbs.  He weighs about 170-175.  With him, his 4 GPSs, tools, and half tanks, his plane was already near 2100 lbs.  I was light with half tanks.  I figured my plane at 1410 lbs, me at 180, and half tanks at 150 lbs.  My TO weight was around 1750 lbs.  We did a flight-of-2 take-off.  I figured, being  lighter, I could at least stay pretty close to him during a climb.  Boy was I wrong.  By 4000 feet MSL (1500 foot AGL) he had 1000 feet on me.  Flat out, side-by-side, he is about 1 to 2 knots faster than my Tiger.  There is no substitute for horsepower.  At cruise, say 140 knots, he could dial down to 10 gph or so.  About the same as me.  Sure would be nice to have 260 hp without the weight penalty.



From: Bob Hodo <bob.hodo(at)YAHOO.COM>

To: teamgrumman-list(at)matronics.com

Sent: Thu, September 2, 2010 7:24:56 AM

Subject: RE: Partial Flap Takeoffs



 I can think of two reasons to wait before putting in 7.5 to 10 degrees of flaps, but both are negligible.



1)  They won't be adding drag before the extra lift is needed.  (But they don't add much drag anyway at those settings.

2)  Debris is never kicked up off the runway more aggressively than when the engine is operated at max power... i.e. takeoff.  Even though the exposure from the bottom side of the flap is only slightly more towards the perpendicular, it does offer a little bit more opportunity for a small rock to strike the skin down there.



Last winter I landed at Hardwick Field in Cleveland Tn.  A snow a couple days earlier had caused them to put salt on the runway.  (Never saw that before.)  On take-off, the  color="#000000" face="courier new,courier">[/quote]

   



               [quote][b]

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