Flap settings on takeoff?

Barry

Barry

Pre-takeoff checklist
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Dec 27, 2018
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knoxflier
I fly a stock O-470 engined 1965 182H, and the old POH says for takeoffs to use 0-20 degrees. I know 10-20 degrees is used for short field or soft just to get you off the ground quicker, but about the shortest runway I use is 3500ft with good surface @ my home base. In the heat of the summer for trips I often take off at max gross with the family, and I have to be pretty patient on takeoff with the stall horn making a little noise right off the runway.

But what and how do you use flaps for takeoff, if not short or soft field? How about at gross max, and/or high density altitude? What about normal takeoffs, maybe not max gross, or high density altitude. Winds make a difference?

Love to learn from others here, searching didn’t show much discussion @ flaps on takeoffs. Of course I’m interested in 182s specifically, but others welcome too. I live in Knoxville, so it gets hot and humid in the summer, my 800ft elevation airport density altitude can get to 4-5k.
 
My POH says to use flaps so I use flaps. I figure it saves wear and tare on the gear. Airplane takes off just fine without them, I've done it. But I still use them.
 
Flaps will give you a shorter ground-roll, more positive liftoff, and more clearance over close-in obstacles at the expense of the initial climb rate.

Those are the tradeoffs. Consider which factors are most important on each takeoff in order to determine your takeoff flaps setting.
 
The 172 gets a shorter ground roll but the time to clear to 50 obstacle is the same for 10 degrees. This is why the dropped the suggestion to use the flaps on short field takeoffs. If you have an older manual flap 172 you can start your take-off roll with them retracted (less drag), drop them in prior to rotation to get off the ground, and then bring them out once you have speed.

The Navion gets less ground roll with half flaps if you have a model that supports that (half is set by dropping the flaps to the same level as a fully deflected down aileron). The other advantage is it keeps the speed down with the bigger engines while you get the gear up.
 
Early on I would use 10º flaps until cleared of obstacles and then clean it up. Now almost all of my takeoffs are with a clean wing ...
 
flyingron said:
The 172 gets a shorter ground roll but the time to clear to 50 obstacle is the same for 10 degrees. This is why the dropped the suggestion to use the flaps on short field takeoffs. If you have an older manual flap 172 you can start your take-off roll with them retracted (less drag), drop them in prior to rotation to get off the ground, and then bring them out once you have speed.

The Navion gets less ground roll with half flaps if you have a model that supports that (half is set by dropping the flaps to the same level as a fully deflected down aileron). The other advantage is it keeps the speed down with the bigger engines while you get the gear up.
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Why can’t you do that in a 172 with electric flaps?
 
For the 182 normal take off I like taking off with 10 degrees of flaps. It gets it off the ground quicker and the doesn’t require as hard of a pull to get it to rotate. I will often retract the flaps as soon as I have a positive rate of climb or the obstacle cleared to help trim it up for best rate of climb.

Brian
CFIIG/ASEL
 
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flyingron said:
The 172 gets a shorter ground roll but the time to clear to 50 obstacle is the same for 10 degrees. This is why the dropped the suggestion to use the flaps on short field takeoffs. If you have an older manual flap 172 you can start your take-off roll with them retracted (less drag), drop them in prior to rotation to get off the ground, and then bring them out once you have speed.

The Navion gets less ground roll with half flaps if you have a model that supports that (half is set by dropping the flaps to the same level as a fully deflected down aileron). The other advantage is it keeps the speed down with the bigger engines while you get the gear up.
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Interestingly somewhere during the production of the “N” model 172 Cessna changed the Short field procedure early “N” Models are as you say above. Later Model manuals recommend a slower Vx with 10degrees flaps for obstacle clearance.
 
182 (with canards)
Always 20, except when wind is gusty and I want to stay planted on the runway until more speed, then it’s 10, or even 0 when there’s a lot of cross-wind.
 
Use just enough, but not too much.
 
In our '57 straight tail 172 if you use no flaps you have to pull it off the runway. If you put 10 in it comes off with a little back pressure. Short field no obstacle 20 gets you off pretty quick.
 
Love flaps on take off, very little that it hampers and lots of benefits to getting airborne quicker. Angles and clearances may be similar, but doing such calculations at a slower speed gives the brain more time to process how-goes-it.
 
My POV - whatever the POH says. I see each plane, even each model within the family ( 182 F, G, N, etc.) as different enough to do what is written.
 
Smaller planes act slightly differently. My anemic C150F recommends 10 degrees only for soft sticky fields and notes that climb over 50’ obstacle will be faster with no flaps. Climbing on a hot day with any more than 10 degrees may never happen at all.
 
I wrote my POH... so I do flaps at trailing.. but I’ve done them at -3 degrees and at 15 degrees.
 
WDD said:
My POV - whatever the POH says. I see each plane, even each model within the family ( 182 F, G, N, etc.) as different enough to do what is written.
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So the OP should move the flaps up and down during takeoff?
 
I do not know for the 182, but in a 172 I did some training in, the instructor had me put a little nose down pressure till we reach take off speed to avoid the chirps in ground effect.

Tim

Sent from my HD1907 using Tapatalk
 
My 182 always use 10 degree. I have been back and forth with keeping them in until cruise level. No harm in doing it especially being the 10 degree speed limit is so high on my plane.
 
I've got a '58 182. The only times that I use 10 degrees of flaps for take off are when I'm heavy, or when the runway is less than 3000'.
 
182 requires less elevator input and has a shorter ground roll with 10-20° flaps. Just keep in mind the plane is not configured for best glide if you have an emergency and you may find 0° flaps preferable for x wind takeoff.
 
tspear said:
I do not know for the 182, but in a 172 I did some training in, the instructor had me put a little nose down pressure till we reach take off speed to avoid the chirps in ground effect.
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That's asking for a wheelbarrowing accident.
 
Dan Thomas said:
That's asking for a wheelbarrowing accident.
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Curious, wouldn't it take a much higher speed and/or a lot of down force to lift the tail and cause such a problem?
Note: I just followed the instructor's directions, which was to push forward about a half inch on the yoke until we read "rotation speed". I was renting at the time and needed a BFR, so I know very little about C172.

Tim
 
tspear said:
Curious, wouldn't it take a much higher speed and/or a lot of down force to lift the tail and cause such a problem?
Note: I just followed the instructor's directions, which was to push forward about a half inch on the yoke until we read "rotation speed". I was renting at the time and needed a BFR, so I know very little about C172.

Tim
Click to expand...
Wheelbarrowing is caused by the wing lifting while the nose is held down. It usually happens during landing, with flaps down, when the pilot has too much airspeed. Since angle of attack is dependent on airspeed, the airplane's attitude is nose-low at higher speed, and with flaps down, the angle of incidence of the inboard wing area makes the AoA higher. It's all a recipe for the mains to be off and the nosewheel on, and what you then have is a really nasty taildragger. It has busted many a trike.

Wheelbarrowing segment starts at 5:20.
 
tspear said:
I do not know for the 182, but in a 172 I did some training in, the instructor had me put a little nose down pressure till we reach take off speed to avoid the chirps in ground effect.
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Chirps? What? Seems like a terrible idea.
 
dmspilot said:
Chirps? What? Seems like a terrible idea.
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To avoid the stall warning sounds. On the rental C172 I was in, it was less of a horn and more like a chirp. I never push down on the yoke in my Cirrus when on the ground, and have only done it on the couple of flights for a BFR with a rental C172.
The OP wanted to avoid the stall horn when in ground effect. That is what the BFR instructor told me to do, and gave me the same reason, to get the plane to speed without it leaving the ground before it was ready and avoid the stall horn in ground effect.

Tim
 
tspear said:
To avoid the stall warning sounds. On the rental C172 I was in, it was less of a horn and more like a chirp. I never push down on the yoke in my Cirrus when on the ground, and have only done it on the couple of flights for a BFR with a rental C172.
The OP wanted to avoid the stall horn when in ground effect. That is what the BFR instructor told me to do, and gave me the same reason, to get the plane to speed without it leaving the ground before it was ready and avoid the stall horn in ground effect.
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The problem is either a trim indicator not calibrated correctly, or a stall warning not calibrated correctly, or both. Teaching someone improper technique to compensate for an aircraft's faults is not a good practice.
 
Like everything in aviation....it depends.
 
Use 10 or 20 degrees for any takeoff, to decrease the wear on the landing gear and climb better. The only danger of using 20 degrees is that if you retract them before you accelerate, you may stall at low altitude, which could turn ugly. So, take off with 20, after 70 KIAS retract to 10 degrees, and after 80 KIAS fully retract. Easy peasy.
 
Tarheelpilot said:
Why can’t you do that in a 172 with electric flaps?
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I think because of the slow travel down and too fast up, and the fact you have to stop them from going all the way...

In my Cessna 140 w manual flaps which aren’t highly effective- they add lift but no braking type tendency, I can pop mine on the roll w a simple tug on the handle- once airborne I can bleed them off as soon as I’m in the air- just feel em off- as the plane catches speed ease em off so there’s no dip. With electrics ya tend to want more altitude as if you mid call it you can get that flap dump dip... manual allows you the control
 
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