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Using flaps for takeoff

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timb

Joined: 16 Apr 2008
Posts: 77
Location: Frankston, Texas

Posted: Mon Jun 28, 2010 2:07 pm Post subject: Using flaps for takeoff

I just had a conversation with a gentlemen from our airpark who said during the last flyin all the RV-s took off with some flaps.  I had been told previously the flaps in the RV were drag flaps only and did no real good for lift.  I also did my transition training a few years ago with Mike Seager and he did not have me using any flaps for take off.  Since I have not tried it (yet) I was wondering if some of you are using flaps for takeoff and if you can tell any real difference.  Would love to hear your thoughts.



Tim Bryan

RV-6 N616TB

Frankston, Texas

_________________
Tim Bryan
RV-6 Flying
N616TB

rice737(at)msn.com
Guest

Posted: Mon Jun 28, 2010 2:24 pm Post subject: Using flaps for takeoff

Hey Tim,

  

 I don't see how the flaps on RV's would only be drag flaps, if so, they would not lower your stall speed when extended.  Mine surely do. (RV8)  Just like a Piper, Cessna, or Mooney for that matter, adding a little flap (10 degrees or so) should reduce your take off run and get you over the tree line a little faster.  

  

 Good flying,

  

 Paul

 

  

 	  Quote: 	
		   From: N616TB(at)btsapps.com

 To: rv-list(at)matronics.com

 Date: Mon, 28 Jun 2010 17:06:28 -0500

 Subject: RV-List: Using flaps for takeoff

 

 --> RV-List message posted by: N616TB <N616TB(at)btsapps.com>

 

 I just had a conversation with a gentlemen from our airpark who said during the last flyin all the RV-s took off with some flaps. I had been told previously the flaps in the RV were drag flaps only and did no real good for lift. I also did my transition training a few years ago with Mike Seager and he did not have me using any flaps for take off. Since I have not tried it (yet) I was wondering if some of you are using flaps for takeoff and if you can tell any real difference. Would love to hear your thoughts.

 

 Tim Bryan

 RV-6 N616TB

 Frankston, Texas

&g========================> 
	


 	  Quote:

tcone1(at)comcast.net
Guest

Posted: Mon Jun 28, 2010 2:41 pm Post subject: Using flaps for takeoff

I only use flaps on takeoff when I have someone in the  back seat.  I'm certain the tail comes up more easily with a little  flap.

  

 As to whether it improves runway performance in terms of  shortening the required field length or not...are you kidding?  It would  have to be a REALLY short field before my -8 started having to worry about  it.

  

 Tim

 [quote]   ---

Terry Watson

Joined: 09 Jan 2006
Posts: 290
Location: Seattle, WA USA

Posted: Mon Jun 28, 2010 3:56 pm Post subject: Using flaps for takeoff

Way back before the turn of the century when I got my free ride in the factory RV-8a here at Arlington, WA with Bill Benedict, then general manager of Van’s, I remember him commenting that although it wasn’t necessarily recommended procedure, he “did it like a Cessna” and put in a little bit of flaps on takeoff. I don’t recall his reason, if he gave me one.  

   

Terry  

Stalled (on the ground) RV-8A project  

       

From: owner-rv-list-server(at)matronics.com [mailto:owner-rv-list-server(at)matronics.com] On Behalf Of Timothy E. Cone

 Sent: Monday, June 28, 2010 3:36 PM

 To: rv-list(at)matronics.com

 Subject: Re: Using flaps for takeoff  

  

  

     

I only use flaps on takeoff when I have someone in the back seat.  I'm certain the tail comes up more easily with a little flap.  

    

   

    

As to whether it improves runway performance in terms of shortening the required field length or not...are you kidding?  It would have to be a REALLY short field before my -8 started having to worry about it.  

    

   

    

Tim  

   	  Quote: 	
		      

----- Original Message -----   

    

From: Paul Rice (rice737(at)msn.com)   

    

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

    

Sent: Monday, June 28, 2010 3:23 PM  

    

Subject: RE: Using flaps for takeoff  

    

   

  

Hey Tim,

  

 I don't see how the flaps on RV's would only be drag flaps, if so, they would not lower your stall speed when extended.  Mine surely do. (RV8)  Just like a Piper, Cessna, or Mooney for that matter, adding a little flap (10 degrees or so) should reduce your take off run and get you over the tree line a little faster.  

  

 Good flying,

  

 Paul

  

  

 > From: N616TB(at)btsapps.com

 > To: rv-list(at)matronics.com

 > Date: Mon, 28 Jun 2010 17:06:28 -0500

 > Subject: Using flaps for takeoff

 > 

 > --> RV-List message posted by: N616TB <N616TB(at)btsapps.com>

 > 

 > I just had a conversation with a gentlemen from our airpark who said during the last flyin all the RV-s took off with some flaps. I had been told previously the flaps in the RV were drag flaps only and did no real good for lift. I also did my transition training a few years ago with Mike Seager and he did not have me using any flaps for take off. Since I have not tried it (yet) I was wondering if some of you are using flaps for takeoff and if you can tell any real difference. Would love to hear your thoughts.

 > 

 > Tim Bryan

 > RV-6 N616TB

 > Frankston, Texas

 &g========================

 

 > 

 > 

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acepilot(at)bloomer.net
Guest

Posted: Mon Jun 28, 2010 3:57 pm Post subject: Using flaps for takeoff

I'm not sure with RVs, but....wouldn't flaps (ie 10 degrees) be used for 

soft field takeoffs and no flaps for short field takeoffs (ie clearing 

trees at the end of a short field)?  That's how it works with Cessnas 

and I assume Pipers and Mooneys as well.  That's the way I was taught 

(in our Cessna 140), but maybe that's old school thinking 



Scott

http://corbenflyer.tripod.com/

Flying Corben Junior Ace - Building RV-4

Gotta Fly or Gonna Die



Paul Rice wrote:

 	  Quote: 	
		   Hey Tim,

  

 I don't see how the flaps on RV's would only be drag flaps, if so, 

 they would not lower your stall speed when extended.  Mine surely do. 

 (RV8)  Just like a Piper, Cessna, or Mooney for that matter, adding a 

 little flap (10 degrees or so) should reduce your take off run and get 

 you over the tree line a little faster. 

  

 Good flying,

  

 Paul

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Mon Jun 28, 2010 4:01 pm Post subject: Using flaps for takeoff

Well, I can tell you that in a Cessna 170B and up, flaps shorten takeoff 

roll and clearing an obstacle until DA is more than 4500 ft. The old 

ones used 20 degrees until the 172 added a notch for 10 degrees and that 

was what was used. The Mooney uses 15 degrees of flaps for all takeoffs 

unless crosswind is too strong to handle with flaps, regardless of DA.

On 6/28/2010 4:56 PM, Scott wrote:

 	  Quote: 	
		   



 I'm not sure with RVs, but....wouldn't flaps (ie 10 degrees) be used 

 for soft field takeoffs and no flaps for short field takeoffs (ie 

 clearing trees at the end of a short field)?  That's how it works with 

 Cessnas and I assume Pipers and Mooneys as well.  That's the way I was 

 taught (in our Cessna 140), but maybe that's old school thinking 



 Scott

 http://corbenflyer.tripod.com/

 Flying Corben Junior Ace - Building RV-4

 Gotta Fly or Gonna Die



 Paul Rice wrote:

> Hey Tim,

>

> I don't see how the flaps on RV's would only be drag flaps, if so, 

> they would not lower your stall speed when extended.  Mine surely do. 

> (RV8)  Just like a Piper, Cessna, or Mooney for that matter, adding a 

> little flap (10 degrees or so) should reduce your take off run and 

> get you over the tree line a little faster.

> Good flying,

>

> Paul

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

acepilot(at)bloomer.net
Guest

Posted: Mon Jun 28, 2010 4:24 pm Post subject: Using flaps for takeoff

I can see how 10 degrees might lessen the takeoff roll due to being able 

to lift off at a slightly lower airspeed.  Can anyone explain why the 

obstacle clearance would be better with flaps down?  There is more drag, 

so wouldn't rate of climb be slightly less?  I suppose if you climb at 

just above stall speed, your ground speed would be lower, thus taking 

longer to get to that tree line?  So, why do instructors teach flaps for 

soft field and no flaps for short field?



What does the POH in the 170B say about soft and short field ops?



Scott

Kelly McMullen wrote:

 	  Quote: 	
		   



 Well, I can tell you that in a Cessna 170B and up, flaps shorten 

 takeoff roll and clearing an obstacle until DA is more than 4500 ft. 

 The old ones used 20 degrees until the 172 added a notch for 10 

 degrees and that was what was used. The Mooney uses 15 degrees of 

 flaps for all takeoffs unless crosswind is too strong to handle with 

 flaps, regardless of DA.

robin(at)PaintTheWeb.com
Guest

Posted: Mon Jun 28, 2010 4:42 pm Post subject: Using flaps for takeoff

The reason is the same for most airplanes, Vans included. More lift.



To Tim’s question that included the statement “all the RV-s took off with

some flaps”



Well it’s hard to get all pilots to do anything the same let alone us

non-conformist “don’t tell me what to do” Experimental pilots. I have never

heard of a flap that was “drag only” seems near pointless, might as well

avoid the weight & complexity of flaps that do not produce lift (and drag).



The entire RV product line is extremely versatile and can take off with no

flaps in most environments. The RV-10 is the only Vans design (I don’t know

about the RV-12) with a 3 degree flap take off setting to improve hard

surface take off performance. That being said adding some flap to all RV

models should shorten take off roll. How much is needed or ideal depends on

the plane, weight configuration, runway surface etc... Most important is

that you as a pilot remember the flaps are deployed and do not exceed Vfe.



So Tim give 10 degrees a test to see how it makes a difference on your ship

denis.walsh(at)comcast.ne
Guest

Posted: Mon Jun 28, 2010 5:06 pm Post subject: Using flaps for takeoff

I can't speak for Cessnas, since I have very little time in them.   

Every other airplane I have flown is designed to get off as soon as it  

can, that is at the lowest speed with which you can be assured of  

flying under good control.  I have not flown any airplane which takes  

off without using flaps, if it has them.



The RV-6 I do know about and have quite a few take offs.  Here is my  

take:



the first 10 degrees (1/4) flap is mostly a lift gain and very little  

drag added at low speed.  You also get a new MAC line which gives you  

a higher angle of attack at a given deck angle.  If you go further  

than 10, you start getting mostly drag and little or no add to the  

lift.  As I see it, your choice is to use 10 flaps and get off a  

little sooner, or use no flaps and roll a little longer.  I believe  

the plane will accelerate better once the wheels get air under them,  

so the obstacle clearance will be better, too.  Lastly, the deck angle  

is lower with the ten flaps and you can see better for that point in  

the take off where you are just lifting off.  Retracting the flaps is  

the first thing I do after take off. before boost pump, RPM, or  

throttle.



Consequently, I always use 10 flap for take off, except in a severe  

cross wind (above 25K).  In that case I am going to "pull it off" for  

take off  with a raid rotation.  If you use any flap in that condition  

it may crow hop toward the down wind side of the runway.  Very  

difficult to control..



A lot of RV guys don't use flap for take off and I don't think it is a  

big deal.  I do recommend every one try it, and try some stalls at 10  

also.  I think you will find the plane has a much more solid feel at  

low airspeeds with the flap down a little.  My personal observation is  

that those folks who don't use flaps are operating at a lot higher  

airspeed than I am.  That's ok too.  If you are going to not lift off  

until you have 70 knots then why would you use flaps?  Same applies  

for landing.



I will offer that my tires last longer than most.  Personally I  

believe this to be because I try to touch down at 45K, and take off at  

the same speed.



I don't think there is a good solution for everyone.  For those who  

don't fly much it makes sense (to me)  to use higher speeds and longer  

take off rolls.  That is not for me, however.



For most of us, the RV normally accelerates so fast that this one or  

two knot difference in stall/lift off speed is hard to even notice any  

way.  You will really notice it at high altitude hot day max gross  

weight.



I hope this "one man's opinion" helps.  Everyone sees it a little  

different.



Denis



RV-6A  4,300 take offs, 4300 landings

On Jun 28, 2010, at 4:06 , N616TB wrote:



 	  Quote: 	
		   



 I just had a conversation with a gentlemen from our airpark who said  

 during the last flyin all the RV-s took off with some flaps.  I had  

 been told previously the flaps in the RV were drag flaps only and  

 did no real good for lift.  I also did my transition training a few  

 years ago with Mike Seager and he did not have me using any flaps  

 for take off.  Since I have not tried it (yet) I was wondering if  

 some of you are using flaps for takeoff and if you can tell any real  

 difference.  Would love to hear your thoughts.



 Tim Bryan

 RV-6 N616TB

 Frankston, Texas

Gary.A.Sobek

Joined: 09 Jan 2006
Posts: 217
Location: SoCAL USA

Posted: Mon Jun 28, 2010 5:08 pm Post subject: Using flaps for takeoff

Tim:



I do not use flaps for takeoff. I was not able to to measure any difference in takeoff with no flaps, 10 flaps, and 20 flaps.  This was over 12.5 years ago. 



I will use 10 flaps on SOFT grass fields. I do not think it reduces ground roll on grass but I feel that it may reduce some of the weight on the mains

ceengland(at)bellsouth.ne
Guest

Posted: Mon Jun 28, 2010 6:08 pm Post subject: Using flaps for takeoff

On 6/28/2010 5:06 PM, N616TB wrote:

 	  Quote: 	
		   



 I just had a conversation with a gentlemen from our airpark who said during the last flyin all the RV-s took off with some flaps.  I had been told previously the flaps in the RV were drag flaps only and did no real good for lift.  I also did my transition training a few years ago with Mike Seager and he did not have me using any flaps for take off.  Since I have not tried it (yet) I was wondering if some of you are using flaps for takeoff and if you can tell any real difference.  Would love to hear your thoughts.



 Tim Bryan

 RV-6 N616TB

 Frankston, Texas

    

As others have said, they definitely add lift.
	




I came to a purchased -4 after ~200 hrs in a Swift, with flap settings 

of full or none (never used for T/O). Never thought to try T/O flaps 

through 7 years of flying that 1st -4, and through about 3 or 4 years of 

flying the 2nd one. Then one day at a neighboring strip's flyin, I 

forgot to retract them (full flaps) on T/O. I was off much quicker than 

expected, and seemingly near pattern altitude before the end of the 

strip. Felt like departing into a 20kt headwind. Since then I've played 

with them several times, but just for fun. Even with only 160 hp, it 

would take a really short strip to make flaps seem necessary. On the 

obstacles issue, I'm no authority but I'd assume that the reason 

flaps-down gets you over obstacles better is that you have an improved 

climb *angle*.



Anyway, I can't see any reason to avoid using them on T/O,  except the 

surprise you might get if you aren't prepared to be off the ground so 

quickly. Try it; you might like it. 



Charlie

Slobovia Outernational

flying purchased -4; -7 finish kit

jsflyrv(at)verizon.net
Guest

Posted: Mon Jun 28, 2010 7:39 pm Post subject: Using flaps for takeoff

Hi Gary,

Living 6 miles form Van and watching him fly frequently, I guess the 

best evidence for using flaps is to watch him takeoff, almost always uses

flaps and consistently shorter takeoff roll then most others.

RV6 Flyer wrote:

 	  Quote: 	
		   Tim:

 I do not use flaps for takeoff. I was not able to to measure any 

 difference in takeoff with no flaps, 10 flaps, and 20 flaps.  This was 

 over 12.5 years ago.

 I will use 10 flaps on SOFT grass fields. I do not think it reduces 

 ground roll on grass but I feel that it may reduce some of the weight 

 on the mains.

 If anyone has some data that shows a difference, please share it.  

 Also let us know what model RV, HP, and prop.

 Gary A. Sobek

 "My Sanity" RV-6 N157GS O-320 Hartzell,

 2,381+ Flying Hours So. CA, USA

 > From: N616TB(at)btsapps.com

 > To: rv-list(at)matronics.com

 > Date: Mon, 28 Jun 2010 17:06:28 -0500

 > Subject: Using flaps for takeoff

 >

 > 

 >

 > I just had a conversation with a gentlemen from our airpark who said 

 during the last flyin all the RV-s took off with some flaps. I had 

 been told previously the flaps in the RV were drag flaps only and did 

 no real good for lift. I also did my transition training a few years 

 ago with Mike Seager and he did not have me using any flaps for take 

 off. Since I have not tried it (yet) I was wondering if some of you 

 are using flaps for takeoff and if you can tell any real difference. 

 Would love to hear your thoughts.

 >

 > Tim Bryan

 > RV-6 N616TB

 > Frankston, Texas

 > ======================

 >=======

 >

 >

 >

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Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Mon Jun 28, 2010 7:53 pm Post subject: Using flaps for takeoff

POH for a C170B last produced in 1956? Surely you jest. It had a one page 5X8" two sided FAA approved flight manual. You climb at Vx, which for most planes is flaps and gear down. Best angle of climb, which is what you need when obstacle is near. The FAA short field definition rarely meets real world...paved runway, just short distance to obstacle. Most real world short fields are also either soft or rough fields and flaps are needed. Just my experience in 700 hours of flying 170B in Alaska. Instructors teach what the FAA dictates to pass the test. I do happen to have a C177B POH handy, which calls for 10 degrees for normal takeoff and 15 degrees for max performance takeoff:

 [img]cid:part1.04030601.09070902(at)aviating.com[/img]

 

 [img]cid:part2.06050302.01040504(at)aviating.com[/img]

 

 On 6/28/2010 5:24 PM, Scott wrote:  	  Quote: 	
		  --> RV-List message posted by: Scott <acepilot(at)bloomer.net> (acepilot(at)bloomer.net)   

   

 I can see how 10 degrees might lessen the takeoff roll due to being able to lift off at a slightly lower airspeed.  Can anyone explain why the obstacle clearance would be better with flaps down?  There is more drag, so wouldn't rate of climb be slightly less?  I suppose if you climb at just above stall speed, your ground speed would be lower, thus taking longer to get to that tree line?  So, why do instructors teach flaps for soft field and no flaps for short field?   

   

 What does the POH in the 170B say about soft and short field ops?   

   

 Scott   

   

   

 Kelly McMullen wrote:   

    	  Quote: 	
		  --> RV-List message posted by: Kelly McMullen <kellym(at)aviating.com> (kellym(at)aviating.com)     

     

 Well, I can tell you that in a Cessna 170B and up, flaps shorten takeoff roll and clearing an obstacle until DA is more than 4500 ft. The old ones used 20 degrees until the 172 added a notch for 10 degrees and that was what was used. The Mooney uses 15 degrees of flaps for all takeoffs unless crosswind is too strong to handle with flaps, regardless of DA.

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_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

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