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  #11  
Old 09-27-2012, 08:18 AM
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Ironflight Ironflight is offline
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Unless I am operating from a VERY short or soft field, where it is a real question if I will get out or not (and for an RV, that is way less than 1,00'), I just leave the flaps up. I know this is counter to a lot of folks thoughts, but the RV performance is so good, and you'll be off the ground so quickly, that the task of messing with the flaps close to the ground - while not accelerating above the VERY LOW "flap deployed" speed is, for me a distraction I don't want. Sure, there are special cases where i might do it - but these aren't Boeings whose wings unfold to generate enough lift to fly.

I don't really have a problem that many folks use flaps for take-off...I just don't like to be having to mess with stuff at that point when I can simply just fly the airplane. On normal runways, the extra half-second I get off earlier with the flaps doesn't mean that much.
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  #12  
Old 09-27-2012, 12:07 PM
drmax drmax is offline
 
Join Date: Apr 2006
Location: Martinsville, IN
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Default my elect. flaps

The builder told be they are set for 10, 20 and 30 degrees, holding the switch 1 second to get each notch. I'll hold her down a bit longer, but like trying to hold down a bull fixing to get branded! I will NOT use 20, so you folks need not worry. Thx for being with me on this. DM
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  #13  
Old 09-27-2012, 12:37 PM
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Sam Buchanan Sam Buchanan is offline
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Quote:
Originally Posted by Ironflight View Post
Unless I am operating from a VERY short or soft field, where it is a real question if I will get out or not (and for an RV, that is way less than 1,00'), I just leave the flaps up. I know this is counter to a lot of folks thoughts, but the RV performance is so good, and you'll be off the ground so quickly, that the task of messing with the flaps close to the ground - while not accelerating above the VERY LOW "flap deployed" speed is, for me a distraction I don't want. Sure, there are special cases where i might do it - but these aren't Boeings whose wings unfold to generate enough lift to fly.

I don't really have a problem that many folks use flaps for take-off...I just don't like to be having to mess with stuff at that point when I can simply just fly the airplane. On normal runways, the extra half-second I get off earlier with the flaps doesn't mean that much.
Agreed. The original post was asking how to achieve a maximum performance takeoff and that is how the thread got off on using flaps.

There are only two short grass strips in my area where I use flaps for takeoff and then only if hot and/or heavy. Any other time is just isn't worth the effort.
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  #14  
Old 09-27-2012, 12:57 PM
Wayne Gillispie Wayne Gillispie is offline
 
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Default Ditto...

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Originally Posted by N941WR View Post
Two options, the first is don't climb after you lift off. Fly it in ground effect, and inch off the ground, until 65, then rotate and accelerate to your desired climb speed. That won't take very long or take up more room.

As for the flap setting, I lower the aileron and drop to flaps to match them. That gives you 15* +/- which works out to about 1/2 flaps in the -9.
I would get a good Vx climb going until 100' or more AGL, then retract flaps incrementally. If you get close to flap limiting speeds, pull the nose up more.

In my -10 at gross on 2100' asphalt(Cedar Key) no flaps needed as I am off by 1000'-1500' depending on temps. In his -9 at gross, fixed pitch, 160 hp...I'd use flaps. We CS prop drivers sometimes think all RV's accelerate like ours and they just won't do it.
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Last edited by Wayne Gillispie : 09-27-2012 at 01:08 PM.
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  #15  
Old 09-27-2012, 01:05 PM
170 driver 170 driver is offline
 
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My RV 9 gets off well before 900 ft,,,it's a 150 hp FP,,,Vans specs say 300 ft with 160 hp...I can't imagine being close to the ground at 900 ft with any flap setting. I rarely use flaps for takeoff at all.
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  #16  
Old 09-27-2012, 02:10 PM
JDRhodes JDRhodes is offline
 
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Quote:
Originally Posted by Ironflight View Post
Unless I am operating from a VERY short or soft field, where it is a real question if I will get out or not (and for an RV, that is way less than 1,00'), I just leave the flaps up. I know this is counter to a lot of folks thoughts, but the RV performance is so good, and you'll be off the ground so quickly, that the task of messing with the flaps close to the ground - while not accelerating above the VERY LOW "flap deployed" speed is, for me a distraction I don't want. Sure, there are special cases where i might do it - but these aren't Boeings whose wings unfold to generate enough lift to fly.

I don't really have a problem that many folks use flaps for take-off...I just don't like to be having to mess with stuff at that point when I can simply just fly the airplane. On normal runways, the extra half-second I get off earlier with the flaps doesn't mean that much.
I've always used take off flaps in the RV-9, but don't in the -7. The progressive fowler-style flaps on the -9 seem to provide a little more benefit than the flat planks on the less sofisticated RV's

Regardless of length, I like the idea of getting the airplane off the relatively rough grass as soon as possible. I'd rather be flying, and accelerating, in ground effect than rolling another 50 feet in the grass.

I'll clean up at 100+ feet with a good climb rate established. Just watch the flap speeds at < 90 mph
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  #17  
Old 09-27-2012, 05:36 PM
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Jeff R Jeff R is offline
 
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Given a -xA, I would be hesitant to hold the nose down at all on takeoff. You don't want to be flipping over at full power! I always pull the stick back on takeoff, and am off within 400 feet, if that, with an IO-320.
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  #18  
Old 09-27-2012, 05:49 PM
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Mel Mel is offline
 
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Default As my first instructor always told me.....

Quote:
Originally Posted by Jeff R View Post
Given a -xA, I would be hesitant to hold the nose down at all on takeoff. You don't want to be flipping over at full power! I always pull the stick back on takeoff, and am off within 400 feet, if that, with an IO-320.
"That nose wheel is for taxiing only, not for take-off or landing!"
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  #19  
Old 09-27-2012, 07:12 PM
drmax drmax is offline
 
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Quote:
Originally Posted by 170 driver View Post
My RV 9 gets off well before 900 ft,,,it's a 150 hp FP,,,Vans specs say 300 ft with 160 hp...I can't imagine being close to the ground at 900 ft with any flap setting. I rarely use flaps for takeoff at all.
what is your MPH at lift off, then? Also, your prop type? I don't understand why I'm not getting your results, if you have a metal prop like mine. I'm in Indiana and low densisty altitude, as of late. Thx, DM
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  #20  
Old 09-27-2012, 07:21 PM
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N941WR N941WR is offline
 
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Quote:
Originally Posted by Jeff R View Post
Given a -xA, I would be hesitant to hold the nose down at all on takeoff. You don't want to be flipping over at full power! I always pull the stick back on takeoff, and am off within 400 feet, if that, with an IO-320.
These suggestions for a -9(A). What works best in a short wing RV or an RV-10 or 12 might be different.
The proper soft field technique is to have 10 to 15 deployed, hold the stick all the way back, do not stop at the end of the runway. Remember, this is a soft field and you could sink in. As the plane starts to accelerate, give it some forward stick to keep the nose just an inch off the ground. This means you have to give it progressively more forward stick as you accelerate. When the plane lifts off, lower the nose some more to fly in ground effect as the plane gains more speed. Even with a FP prop, the plane will push you in the back of the seat once you are off the ground. After say 65 kts/ 70 MPH start your climb and establish your Vx or Vy speeds, depending on any obstructions on the field, as you retract the flaps.
If your nose is too high, you will make a longer than necessary takeoff roll. Too low and your front wheel will still be in the weeds.

BTW, the few times I have flow an ?A? model, I use the same technique even if on pavement.

Landings are another thing. Full flaps 65 to 70 MPH, depending on my load. Just before touchdown, I add very small amount of power to arrest the sink rate and just kiss the mains on. As soon as the mains are on, I pull the power off while working the stick aft. I let the nose drop on its own, again while holding the stick aft. The stick remains aft until shutdown.
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