Flaps on take-off?

[Super Dave]

I would disregard the comments bashing your instructor, after all, Bob Kromer recommends no flap takeoffs and he was a Mooney factory engineering test pilot.

As for the POH recommendation, I don't know about your E, but my 76F POH says to set flaps at "TAKEOFF OR AS DESIRED". Even if your POH only recommends takeoff flaps, it is just a recommendation unless it is in the limitations section.

My routine is to check the distance required to clear a 50' obstacle from my POH, and then I double that number. If the result is anything close the the runway available, I use takeoff flaps. If not, I prefer flaps up because once airborne, the airplane accelerates more quickly and climbs at a better rate and gradient with flaps up.

Many pilots have the sense that climb performance is somehow improved by flaps, but this is incorrect. Climb performance is determined by excess power or thrust, not excess lift. Since flaps increase drag, they reduce excess power and degrade climb performance. If flaps improved climb performance, we would use them all the way to cruising altitude.

On the other hand, flaps can help us clear an obstacle at the end of a short runway. By getting airborne in less distance, flaps help us start our climb further from the obstacle, and that obstacle can be cleared with greater margin, even with the degraded climb performance.

My advice is to become comfortable with both configurations and use either depending on the situation.

[Shadrach]

I thought they went all-electric in 69, like the others. I'm not up on annual production rates, but I flew an F that, like my C, is all electric. Different actuators, but electric.

I was also taught when transitioning that flaps aren't needed for every takeoff, and it was confirmed at the PPP shortly afterwards.

Flaps are a tool to use, and every takeoff, like every landing, is slightly different (wind speed/direction, weight, CG, distance to & height of obstacles, runway surface condition, runway slope, etc.) . Sometimes a different tool works better. I don't treat everything like a nail just because I have a hammer--I also have wrenches and screwdrivers.

All electric became standard in 1970 IIRC. Electric may have been an option in 69. However, in terms of production numbers, well over 800 of the total (~1250) F models built were manufactured before 1970.

[Seth]

You certainly don't need flaps for take off, but you will not get the book numbers in the POH without them (good chance you won't with them either). There is absolutely no logical reason for your CFI to instruct you not to use flaps. Some pilots prefer the way the aircraft rotates sans flaps (I believe Bob Kromer is in this camp). Whatever floats your boat...

Flaps do add lift to the equation, but more importantly IMO, deploying flaps changes the wing chord line, which in effect increases the angle of incedence. This means that at a given angle of attack, all other things being equal, the pilot gets better forward visibility ove the nose.

Here's a good exercise: go out and slow to flap speed with no flaps, take note of your sight picture, and then add "take-off" flaps, re-trim for level flight. I think you'll find that you're flying along slightly nose down compared to flaps up. You could do the same thing in a no flaps climb. Either way adding flaps brings the nose down because it increases angle of incedence.

I've done no flap take-offs (occasionally even on purpose). I personally see no benefit from doing them. I think the plane rotates beautifully with flaps, and I'll take all of the forward visibility I can get...especially in an airport environment!

+1

 

The plane "leaps" off the runway when the flaps are in line with the down deflection of aileron.  I set take off flaps for every departure (two pumps previously, now electric), and look out at each wing to ensure that when I fully deflect the aileron, the flap and aileron are flush.  That I've noticed gets me the best "leapaing" sensation off the runway. 

 

Twice I have tried without them and have a much lower initial climb rate and angle - just a flatter climb eating up more runway.

 

The E is a peformance champ - use the take off flaps setting and you'll see a difference.

 

 

-Seth

[Seth]

Yes, if you haven't figured it out yet, this is the twilight zone and you just happen to be in another episode. The last episode was whether not we should fly ROP or LOP.

Bladders, sealed wing / LED vs traditional / LOP, ROP / Night flying / twin, single

 

Flaps, no flaps - we'll just add this one to the list.

 

-Seth

[DAVIDWH]

JUST TO KEEP IT GOING:

 

No flap take offs in long bodied Mooneys  ie. (M-20R) will increase the propensity for a tail drag.

 

Reference: Former owner of my aircraft with airframe logs as documentation.

[Shadrach]

+1

 

The plane "leaps" off the runway when the flaps are in line with the down deflection of aileron.  I set take off flaps for every departure (two pumps previously, now electric), and look out at each wing to ensure that when I fully deflect the aileron, the flap and aileron are flush.  That I've noticed gets me the best "leapaing" sensation off the runway. 

 

Twice I have tried without them and have a much lower initial climb rate and angle - just a flatter climb eating up more runway.

 

The E is a peformance champ - use the take off flaps setting and you'll see a difference.

 

 

-Seth

Similar to my experience, though I've never gauged it against aileron deflection.  Flatter climb is due to reduced AOA.  I maintain that the effective AOI with TO flaps allows the airplain to climb at the same AOA with the longitudinal axis of the fuselage at lesser angle relative to trajectory. Which means... better over the nose visability for a given ROC. 

[PMcClure]

All electric became standard in 1970 IIRC. Electric may have been an option in 69. However, in terms of production numbers, well over 800 of the total (~1250) F models built were manufactured before 1970.

My 69 F model (built in 68) had hydraulic flaps and manual gear. 

[Shadrach]

I would disregard the comments bashing your instructor, after all, Bob Kromer recommends no flap takeoffs and he was a Mooney factory engineering test pilot.

As for the POH recommendation, I don't know about your E, but my 76F POH says to set flaps at "TAKEOFF OR AS DESIRED". Even if your POH only recommends takeoff flaps, it is just a recommendation unless it is in the limitations section.

My routine is to check the distance required to clear a 50' obstacle from my POH, and then I double that number. If the result is anything close the the runway available, I use takeoff flaps. If not, I prefer flaps up because once airborne, the airplane accelerates more quickly and climbs at a better rate and gradient with flaps up.

Many pilots have the sense that climb performance is somehow improved by flaps, but this is incorrect. Climb performance is determined by excess power or thrust, not excess lift. Since flaps increase drag, they reduce excess power and degrade climb performance. If flaps improved climb performance, we would use them all the way to cruising altitude.

On the other hand, flaps can help us clear an obstacle at the end of a short runway. By getting airborne in less distance, flaps help us start our climb further from the obstacle, and that obstacle can be cleared with greater margin, even with the degraded climb performance.

My advice is to become comfortable with both configurations and use either depending on the situation.

I would add 2 things.

 

1) I've read Kromer for years and just because he does it or did it at one time does not make it optimal. He also advocated leaning to 100 ROP immediately after take-off and flew many of his evaluation AC at sustained climb CHTs ranging from 420 - 450df for extended periods of time. http://mooneyspace.com/topic/10405-hes-moved-again-bob-kromer/#entry121890. I say no thanks to that advice, but to each their own.

 

2) Your analysis of no flap climbs ony takes parasitic drag into account. To be accurate, induced drag should also be accounted for, and the effective reduction in AOI will yield less induced drag at climb AOAs.  I've not seen the numbers, so I don't know what the net is. Probably not much...

[pinerunner]

I routinely use flaps for takeoff in my 63 M20E but I can see one point of sense in what your CFI taught you.  I our older E models the maximum flap extended speed of 100 mph is very easy to exceed. Taking off without flaps will require a bit more speed but has been saving you that hassle. You'll need them for shorter strips so you might as well bring them into your reperatoire. With 50 hours you're probably well aware of the importance of speed control in these planes. I take that maximum flap speed very seriously and often wish they'd made my flaps a bit more rugged. Your decision as PIC! 

[Chimpanzee]

Hmm,

mostly use falps on T/O, but forgot them too. However, since N201MKT lives in Tempe, I will experiment more with no flaps t/o as mine lives next tdoor in Arizona. I do nearly all landing with 1/2 flaps (and slip if required).

norbert

[N33GG]

What more can be said?  You might get away with no flap policy in most small GA planes, but there are many planes I have flown that would be disaster and an NTSB report without recommended flaps.

 

Learn each aircraft and abide by the POH.  Or have a lot of real test pilot skills and experience.... some planes are not so forgiving.

 

Just my 2 cents.  FWIW, YMMV, etc etc etc

[Shadrach]

I routinely use flaps for takeoff in my 63 M20E but I can see one point of sense in what your CFI taught you.  I our older E models the maximum flap extended speed of 100 mph is very easy to exceed. Taking off without flaps will require a bit more speed but has been saving you that hassle. You'll need them for shorter strips so you might as well bring them into your reperatoire. With 50 hours you're probably well aware of the importance of speed control in these planes. I take that maximum flap speed very seriously and often wish they'd made my flaps a bit more rugged. Your decision as PIC! 

 

You raise a good point, though I believe some S/Ns have a higher partial flap speed... I think they are plenty rugged enough to go over flap speed. Many forgetful pilots have tested them over the years. The newer planes have a higher flap speed and I do not believe there significant structural changes to the system. Not saying to ignore Max flap speed, just saying they're not going to fall off!

[gregwatts]

_{I subscribe to the party of ROP, No flap TO ( unless conditions warrant them), and partial flap landings, and sealed tanks!}

[Bob_Belville]

_{I subscribe to the party of ROP, No flap TO ( unless conditions warrant them), and partial flap landings, and sealed tanks!}

Wow, I oppose every one of your theological positions and therefore must brand you a heretic. 

[gregwatts]

Wow, I oppose every one of your theological positions and therefore must brand you a heretic. 

The key word in the definition of your "branding" is ...........OPINION!      Just sayin'

[Shadrach]

_{I subscribe to the party of ROP, No flap TO ( unless conditions warrant them), and partial flap landings, and sealed tanks!}

 

1 in 4 is better than 0 in 4....

[N201MKTurbo]

Here in Arizona, I prefer to TO barefoot instead of wearing flip flops. What do you all do about that...

[fantom]

_{I subscribe to the party of ROP, No flap TO ( unless conditions warrant them), and partial flap landings, and sealed tanks!}

 

Glad you stuck that last one in.....so it's one out of four

 

Oh, and I'm staying far away from any stinky barefoot pilots who refuse to use TO flaps

[gregwatts]

I am in the flip flop party.................

[Shadrach]

Barefoot is the way to go.  My landings in the Decathlon improved greatly when I shed my shoes. Now that winter is here in MD, back to shoes. My back seater will likely be queezy from the yaw caused by my over active feet...

[Bob_Belville]

I thought I had added this history to the no flaps discussion but I do not see it. (It concerns the '66E I now own from 8/17/1968. The plane was not returned to service for 12 years after the owner tried to take off from an 1800' runway with 3 on board @ 85F with a slight tail wind..)

 

a/c damaged in landing accident , this date, Oakdale, CA) NTSB Identification: OAK69D0112

14 CFR Part 91 General Aviation Aircraft: MOONEY M20E, registration: N2566W

 FILE    DATE          LOCATION          AIRCRAFT DATA       INJURIES       FLIGHT                        PILOT DATA      F  S M/N     PURPOSE

3-2768  68/8/17    OAKDALE,CALIF       MOONEY M20E         CR-  0  0  1  NONCOMMERCIAL             PRIVATE, AGE 39, 448

        TIME - 1410                    N2566W              PX-  0  0  2  BUSINESS                  TOTAL HOURS, 250 IN TYPE,

                                       DAMAGE-SUBSTANTIAL  OT-  0  0  0                            NOT INSTRUMENT RATED.

        NAME OF AIRPORT - OAKDALE

        TYPE OF ACCIDENT                                         PHASE OF OPERATION

           STALL: MUSH                                              TAKEOFF: INITIAL CLIMB

        PROBABLE CAUSE(S)

           PILOT IN COMMAND - FAILED TO OBTAIN/MAINTAIN FLYING SPEED

        FACTOR(S)

           PILOT IN COMMAND - MISUSED OR FAILED TO USE FLAPS

           PILOT IN COMMAND - SELECTED WRONG RUNWAY RELATIVE TO EXISTING WIND

           WEATHER - HIGH TEMPERATURE

        WEATHER BRIEFING - NO RECORD OF BRIEFING RECEIVED

        WEATHER FORECAST - UNKNOWN/NOT REPORTED

        SKY CONDITION                                            CEILING AT ACCIDENT SITE

          CLEAR                                                    UNLIMITED

        VISIBILITY AT ACCIDENT SITE                              PRECIPITATION AT ACCIDENT SITE

          5 OR OVER(UNLIMITED)                                     NONE

        OBSTRUCTIONS TO VISION AT ACCIDENT SITE                  TEMPERATURE-F

          NONE                                                      85

        WIND DIRECTION-DEGREES                                   WIND VELOCITY-KNOTS

          315                                                       5

        TYPE OF WEATHER CONDITIONS                               TYPE OF FLIGHT PLAN

          VFR                                                      NONE

        REMARKS- QUARTERING TAIL WIND 5 KNOTS. NO FLAPS. TEMP 85 DEG.

[Mooneymite]

I love this board!  Everyone has at least one opinion and facts to back it up.

 

Just to enter the fray, I'm in the "use flaps for takeoff" camp since:

 

.I fly off of grass

.My POH says to do so

.All the planes I've made a living flying make a lot of noise if the pilot fails to deploy flaps prior to applying take-off power!  In other words, it is part of my habit pattern.

 

Having said that, I can agree that the flaps are a "tool" to be used as the circumstances dictate....even if the POH doesn't.

 

One HUGE reason NOT to use flaps for takeoff is that you don't have to worry about over-speeding them when you forget to retract them....something I've obviously NEVER done....or at least never admitted doing.  

 

Happily, ROP/LOP is not a hot topic for us "carburetor guys".  Otherwise, I'm sure I'd have a strong opinion on that too.

 

So....what do you think about Marvel Mystery oil?  

[N201MKTurbo]

 

I thought I had added this history to the no flaps discussion but I do not see it. (It concerns the '66E I now own from 8/17/1968. The plane was not returned to service for 12 years after the owner tried to take off from an 1800' runway with 3 on board @ 85F with a slight tail wind..)

 

 

This would certinly qualify as a short field where I would use flaps......

 

This is kind of outside the scope of this discussion. We are talking about normal takeoffs, not edge of the envelope stuff.

[N201MKTurbo]

So....what do you think about Marvel Mystery oil?  

 

What happens if you mix MMO and CamGaurd, fly LOP barefoot from a short field with a tailwind over gross with no flaps?????

[Z W]

At the risk of interrupting a pretty funny thread there at the end...

 

The "take off" marker on your flaps is the point at which the flaps start to add more drag than they do lift.  Up to and including that point, the flaps add more lift than drag.

 

Using "take off" flaps will result in a shorter takeoff roll and a steeper angle of climb, meaning your ratio of upward travel to forward travel will improve.  This is helpful for obstacle clearance.  It is also helpful for quickly putting distance between you and the ground and minimizing the amount of time you spend under 1000 AGL, which is the most dangerous time to have an engine failure.

 

That's the theory you can read on these forums.  I've verified it in both an M20C and an M20K.  I use takeoff flaps as a habit unless there's more than about 20 kts of wind.  I will then leave them up to minimize the gusting effect, and with those winds, takeoff roll and angle of climb are great anyways.

 

I spent quite a bit of time on the C model with inop flaps because of a pesky hydraulic leak.  It would take off just fine without them, but rolled longer and didn't climb as well.  It actually does have a nice feel to it that way.  The plane accelerates faster once you get in the air without the flaps.  But it doesn't perform as well.

 

You never know when your engine might quit shortly after takeoff, and I prefer to be as high as possible and as close to the airport as possible when it does.  No-flaps puts you lower and farther away.