Dave Hamblin
(formerly DaveH on old site!)

Ok, my carb ice didn't stir up a lot of controvercy, so lets try another.

For those whose plane has flaps (or if you have had one with flaps for all the Pitts/Extra/Sukhoi drivers), how do you handle them on landings?

Do you drop a bit at a time on downwind,base, final, all at once or ??

As importantly, why??

I have settled on 10 on downwind, 20 on base, 30 on final and if needed (or for fun) 40 on short final. Thats on our C150H.

Just curious what others do and why.

• RE: Flaps....,aboyd, 17:16z, 06-06-02
  • RE: Flaps....,DHamblin, 22:32z, 06-06-02
• RE: Flaps....,avbug, 07:36z, 06-07-02
  • RE: Flaps....,DHamblin, 12:09z, 06-07-02
    • RE: Flaps....,CRodin, 23:34z, 06-07-02
• RE: Flaps....,jerryrosie, 13:22z, 06-07-02
  • RE: Flaps....,Ben_Chiu, 22:43z, 06-07-02
    • RE: Flaps....,DHamblin, 00:26z, 06-08-02
• RE: Flaps....,Ben_Chiu, 22:43z, 06-07-02
  • RE: Flaps....,DHamblin, 00:20z, 06-08-02
    • RE: Flaps....,avbug, 19:14z, 06-08-02
      • RE: Flaps....,DHamblin, 20:03z, 06-08-02
• RE: Flaps....,Patty_Wagstaff, 02:14z, 06-12-02
  • RE: Flaps....,DHamblin, 17:00z, 06-12-02

I think you can come closer to answering your question if you back up a moment, and consider what flaps do.

This is somewhat complex, as flaps come in many variations: split, slotted, fowler, etc.

Keeping the above in mind, as a very rough rule of thumb, up to 15 degrees, flaps increase lift (reduce stall speed) at the cost of increased drag. Beyond 15 degrees, you get very little increase in lift, but an increase in drag.

If you have the power (eg C182) to overcome the drag, you can use some flaps on takeoff to improve your angle of climb.

Also keeping in mind that a number of people die every year on the infamous base-to-final turn, I might recommend a "normal" pattern procedure of 1500 rpm on downwind, flaps 15, then turn base. Too low, increase power. Too high, reduce power, sideslip.

Why not more flap when too high? Well, the problem is that if you apply 40 degrees of flap too early, and start to sink, you will end up having to drag it in with substantial power, as no one likes to raise flaps on final.

I know that sideslips are unfashionable these days, but the wonderful thing about a sideslip is that you can get rid of the drag - unlike dropping flaps.

Also unfashionably, I do not like being out of gliding distance of the runway, when I am at low altitude and my choices are limited.

Flaps of 15 to 40 degrees increase drag, and allow you to approach steeply over obstacles without airspeed increasing. Most of us don't normally approach steeply over obstacles.

Another advantage of flaps 15 is that you can overshoot much more safely, and are more controllable in a crosswind.

Given the plethora of aircraft types and the wide variety of conditions under which they operate (eg very cold temps) it's hard to come up with a one-side-fits-all answer. Do what works for you in your aircraft at your airport

Dave Hamblin
(formerly DaveH on old site!)

All my initial flight training was in a Luscombe (no flaps) so my first few landings with flaps were "nice things these flaps, what do I do with them?".

Flaps and how to use seem to bring up a lot of discussions.

I try to do a variety of landing configurations (I am still a student so thats why I like to get opinions of others.)

Use what you need, when you need it. Gusty or windy in a light airplane, consider a reduced flap setting, or pulling them up just after touchdown. Or full flaps. Use what's required.

Setting specific intervals and positions for adding flap increments is very remedial. It's a good starting point for a student pilot, but at some point each pilot must start to think about it, and put down flaps and make power reductions according to need, rather than by rote.

Typically I'll apply the first increment of flaps as soon as I reach the flap limiting speed for that setting. In my airplane that's 202 knots. Gear speed is right there too; sometimes I'll put in the second increment before gear, sometimes I'll go gear first. It depends what I'm trying to accomplish. I need to slow to 150 KIAS before putting in the final increment, and that usually waits until later in the approach.

Generally I put in my first increment approaching the IAF. If it's an instrument approach, I'll put in the second increment while outbound for the proceedure turn, or prior to intercepting the final approach course. If it's a precision approach, the gear will go down within a dot of the glideslope, and then land flaps when the appropriate speed is reached. If I know I'll be circling, I leave only the 2nd increment of flaps in, until the landing is assured.

However, the circumstances must dictate. If I'm in a Navajo that is flying single engine, I'll be loathe to add much flap or put the gear down until I absolutely need to. Once airspeed and altitude is lost in such an airplane when loaded, one won't get it back. Accordingly, one must be sure that it's the right thing to do and hold off until it is.

On some occasions, putting full flaps in on the downwind may be appropriate. On others, delaying them until on final may be very appropriate. The presence of ice and other considerations may also be important.

There are no hard, fast rules. Use whatever works, considering the circumstances and the need.

Dave Hamblin
(formerly DaveH on old site!)

The morning I soloed (before I realized I was going to solo...) we practiced everything from power-off simulated engine failures, no-flap to full flap (slips with no flap etc). I should have guess something when he had me do a go-around from a 40 degree flap approach at about 100' (when the approach was good). (When my CFI said to stop he was getting out I wondered "gee, am I scaring you that bad )

After hearing people give me horror stories about full (40 degree) flaps on a C150 as to go arounds and flares; I actually found it quite comfortable to do both (after you get used to the steeper approach).

My CFI doesn't require me to do any specific flap settings; if fact he encourages me to try different settings at this point.

Its interesting to hear different theories on these type things!

Ok, here is my two cents worth... when I'm flying a C150/C152/C172 I typically do the following (conditions and traffic permitting, of course):
- When the threshold is 45 degrees off my shoulder I apply carb heat, reduce power to 1500 RPM, raise the nose to slow to Vfe, apply 10 degrees of flap and turn base. This usually sets me up for a nice stable approach and I can add more flap if conditions require.
Good luck and happy landings!
Cary Rodin

I generally apply the first 'notch' of flaps right after pulling power back to about 1700 RPM at midfield downwind to start slowing the C150 down to landing speed (in the 65-70 MPH range). A quick look at altitude when turning base might call for another notch if I'm too high. After established on final, going to 30 degrees is an option, again depending on altitude. Never get to 40 degrees, based on student experience, when both my CFI and I weighted in excess of 200 pounds each. The C150 just wouldn't do a go around with that weight and 40 degrees.

The only "hard and fast" is the first notch of flap when reducing power at mid filed. All the rest is "if I need them" based on if I am too high for that segment of the approach.....

***Reality - The refuge of those who can't handle simulation***
Cheers, Jerry (N94)

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Looks like you guys covered it all pretty well. All I can add is "what's needed" might have to be defined a bit more for newer pilots. For example, one notch of flaps in the pattern is meant to create some drag on faster fliers (a 150 or 172 doesn't need that). The reasons behind this are two fold--you don't want to fly too fast in the pattern, and you don't want to fly slower by flying with the RPM too low if you can help it (too low an RPM increases your chances of carb ice, engine loading up, over cooling, etc.).

The other side of the coin (and proverbial forces of flight) is you don't want to add more flaps than is necessary or prudent. While what's necessary can be defined by how much engine power is required to drag it in or your altitude, I tend to go with what's prudent and that depends on whether you can glide to the airport if you suddenly lose power. Being a by-the-book kind of guy, I instruct my students to land with full flaps regardless of the wind (the FAA recommends that full flaps should be used for all normal landings unless the manufacturer suggests otherwise), because I think the advantages of full flap landings out weigh the disadvantages (lower stall speed, lower landing speed, lower AOA upon approach and landing vs. more things to do in a go-around), but as always, go with what your POH and instructor recommend. Some pilots argue that partial flap landings are safer, but I'm of the belief that speed kills (actually the sudden deacceleration/stop) so the slower you are when you touchdown, the better (the low fatality rate in gliders is attributed to their lower speeds). High winds? Even better because your groundspeed will be lower yet.

When it comes to instrument approaches, there are two schools of thought regarding flaps--I like to call them the optimist and pessimist approach (pardon the pun). What differentiates the two is whether the aircraft is more configured to land or to make the missed approach (me, call me a pessimist when it comes to approaches), but I think we're straying from the original intent of the thread so I'll end here.

Hope this helps!

Ben

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Dave Hamblin
(formerly DaveH on old site!)

Everyone told me (other than my CFI) how difficult 40 degree of flaps would be and go-arounds hard etc etc. "Thats why they don't ave 40 degrees anymore" I have been told.

Well, as we began to practice when we got the 150; I found 40 degree landings to be easier (once the steep approach "picture" was gotten used to!) and go-arounds weren't all that bad.

When I soloed all three landings were 40 degree (by my choice).

Having said that, if I decide up front to do a 40 degree flap landing, I will turn base/final a lot sooner than if its a no-flap or 15 degree flap approach.

Greetings Dave:

> Ok, my carb ice didn't stir up a lot of controvercy, so lets try
> another.

LOL! You might add to your list some other oldies but goodies for future reference:

- downwind turn
- shock cooling
- lean of peak cruise
- lift generation
- best glide

Ben

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Dave Hamblin
(formerly DaveH on old site!)

If I want to stir up things at the RC model field I will bring up the downwind turn!

As an engineer by trade the shock cooling is also good to start!

I have sitting next to me the stick grip that was in the hand of a pilot at a place I flew ag (crop dusting), when he spun in during a downwind turn. The "downwind turn" is both myth, and reality, for different reasons.

An engineer will usually argue against shock cooling. As a mechanic, the arch nemisis of the engineer, I've seen it first hand on numerous occasions.

Dave Hamblin
(formerly DaveH on old site!)

I'll mess up your record, I fully believe in shock cooling.

I will also say that the downwind turn also is a myth and reality. All the airplane cares is about the wind coming over its wings, not whether its upwind, down wind etc.

Still a good argument starter though

Hi Dave

Well, as you know most of the aerobatic airplanes - eg. Decathalon, Pitts, Extra, Sukhoi, etc. - have no flaps. However, when flying airplanes with flaps the key to using them is use them when you need 'em! If you're high, drop them in. If you're low and slower than you want, wait awhile. When you have more experience being PIC you'll see what I mean!

Patty

Dave Hamblin
(formerly DaveH on old site!)

Yea, I figure a few hundred more landings should help .