C172 Flaps up or 10 degrees for takeoff

[Michelle P]

An interesting dilemma.
The manual for the 172 N tells you that 0-10 degrees is acceptable for
takeoff. However it does not tell you what affect it has at low altitude
300 feet MSL Density altitude around 2500 MSL. It only states that it
will have a detrimental affect at high altitude on a hot day. It also
does not give an airspeed for Vy flaps 10 degrees.

In talking to another pilot who has an 172 L has states that his manual
says if 10 degrees flaps are used it will decrease ground roll and
decrease climb rate. Having an overall detrimental affect.

The only definitive number the 172N manual states for flaps 10 degrees
is Vx.

First hand experience seems to confirm what the 172 L manual says.

What do you all think?
Michelle

[Blueskies]

"Michelle P" > wrote in message
nk.net...
> An interesting dilemma.
> The manual for the 172 N tells you that 0-10 degrees is acceptable for takeoff. However it does not tell you what
> affect it has at low altitude 300 feet MSL Density altitude around 2500 MSL. It only states that it will have a
> detrimental affect at high altitude on a hot day. It also does not give an airspeed for Vy flaps 10 degrees.
>
> In talking to another pilot who has an 172 L has states that his manual says if 10 degrees flaps are used it will
> decrease ground roll and decrease climb rate. Having an overall detrimental affect.
>
> The only definitive number the 172N manual states for flaps 10 degrees is Vx.
>
> First hand experience seems to confirm what the 172 L manual says.
>
> What do you all think?
> Michelle
>

1975 C172M manual...

"Normal and obstacle clearance take-offs are performed with wing flaps up. The use of 10° flaps will shorten the ground
run approximately 10%, but this advantage is lost in the climb to a 50-foot obstacle. Therefore, the use of 10° flaps is
reserved for minimum ground runs or for take-off from soft or rough fields. If 10° of flaps are used for minimum ground
runs, it is preferable to leave them extended rather than retract them in the climb to the obstacle. In this case, use
an obstacle clearance speed of 65 mph. As soon as the obstacle is cleared, the flaps may be retracted as the aircraft
accelerates to the normal flaps up climb speed of 80 to 90 mph.

During a high altitude take-off in hot weather where the climb would be marginal with 10° flaps, it is recommended that
flaps not be used for take-off. Flap settings greater than 10° are not recommended at any time for takeoff."

The Take-off checklist has a normal and a maximum performance set of items. Both say Flaps up. The only real difference
is the brakes are held until full power is applied and the run is with the tail slightly low for the max performance
T-O...

The old C-172A book says pretty much the same thing.

From my experience the use of flaps should be reserved for those really rough or rain soaked grass fields with low
obstacles.

[BTIZ]

based on this, I was always told that 10degree flaps on take off where to
get up off that wet grassy runway and accelerate in ground effect, slower
climb rate to be expected, so make sure there are no trees at the other end.

BT

" Blueskies" > wrote in message
. ..
>
> "Michelle P" > wrote in message
> nk.net...
>> An interesting dilemma.
>> The manual for the 172 N tells you that 0-10 degrees is acceptable for
>> takeoff. However it does not tell you what affect it has at low altitude
>> 300 feet MSL Density altitude around 2500 MSL. It only states that it
>> will have a detrimental affect at high altitude on a hot day. It also
>> does not give an airspeed for Vy flaps 10 degrees.
>>
>> In talking to another pilot who has an 172 L has states that his manual
>> says if 10 degrees flaps are used it will decrease ground roll and
>> decrease climb rate. Having an overall detrimental affect.
>>
>> The only definitive number the 172N manual states for flaps 10 degrees is
>> Vx.
>>
>> First hand experience seems to confirm what the 172 L manual says.
>>
>> What do you all think?
>> Michelle
>>
>
> 1975 C172M manual...
>
> "Normal and obstacle clearance take-offs are performed with wing flaps up.
> The use of 10° flaps will shorten the ground run approximately 10%, but
> this advantage is lost in the climb to a 50-foot obstacle. Therefore, the
> use of 10° flaps is reserved for minimum ground runs or for take-off from
> soft or rough fields. If 10° of flaps are used for minimum ground runs, it
> is preferable to leave them extended rather than retract them in the climb
> to the obstacle. In this case, use an obstacle clearance speed of 65 mph.
> As soon as the obstacle is cleared, the flaps may be retracted as the
> aircraft accelerates to the normal flaps up climb speed of 80 to 90 mph.
>
> During a high altitude take-off in hot weather where the climb would be
> marginal with 10° flaps, it is recommended that flaps not be used for
> take-off. Flap settings greater than 10° are not recommended at any time
> for takeoff."
>
> The Take-off checklist has a normal and a maximum performance set of
> items. Both say Flaps up. The only real difference is the brakes are held
> until full power is applied and the run is with the tail slightly low for
> the max performance T-O...
>
> The old C-172A book says pretty much the same thing.
>
> From my experience the use of flaps should be reserved for those really
> rough or rain soaked grass fields with low obstacles.
>

[Brien K. Meehan]

Michelle P wrote:
> In talking to another pilot who has an 172 L has states that his manual
> says if 10 degrees flaps are used it will decrease ground roll and
> decrease climb rate. Having an overall detrimental affect.

I have a 172S manual It's my understanding that, in terms of flaps and
related performance, all models after L are exactly the same.

My manual says that "using 10 degrees of wing flaps reduces the ground
toll and total distance over an obstacle by approximately 10 percent."
For a short field takeoff, that would be an overall beneficial affect,
not detrimental.

It's my experience that, at low airpseeds, 10 degrees of flaps
increases my climb performance substantially.

[Peter Clark]

On 11 Aug 2005 00:11:51 -0700, "Brien K. Meehan"
> wrote:

>Michelle P wrote:
>> In talking to another pilot who has an 172 L has states that his manual
>> says if 10 degrees flaps are used it will decrease ground roll and
>> decrease climb rate. Having an overall detrimental affect.
>
>I have a 172S manual It's my understanding that, in terms of flaps and
>related performance, all models after L are exactly the same.

The newest (G1000) 172S manuals and checklist (and factory transition
training) say 0-10deg is approved, but 10deg is preferred to flaps up
in all conditions due to the decreased ground roll and increased climb
performance, and specifically called for when doing soft/rough field.

[Thomas Borchert]

Michelle,

I have always read the manual to mean that 10 degrees is useful for all
situations where the ground roll should be minimal, e.g. soft fields.
Since we almost only use soft fields here in Germany, I have always
used 10 deg when I flew 172s. It got me some funny looks, though.

--
Thomas Borchert (EDDH)

[Brien K. Meehan]

Are you sure that was due to the flaps? ;-)

[[email protected]]

Michelle P wrote:
> An interesting dilemma.
> The manual for the 172 N tells you that 0-10 degrees is acceptable for
> takeoff. However it does not tell you what affect it has at low altitude
> 300 feet MSL Density altitude around 2500 MSL. It only states that it
> will have a detrimental affect at high altitude on a hot day. It also
> does not give an airspeed for Vy flaps 10 degrees.
>
> In talking to another pilot who has an 172 L has states that his manual
> says if 10 degrees flaps are used it will decrease ground roll and
> decrease climb rate. Having an overall detrimental affect.
>
> The only definitive number the 172N manual states for flaps 10 degrees
> is Vx.
>
> First hand experience seems to confirm what the 172 L manual says.
>
> What do you all think?
> Michelle

I used to rent a 172L a lot many years ago, and used 10 degrees to
reduce the takeoff roll but for me it *increased* the rate of climb
slightly at airspeeds between Vx and Vy. Any more than 10 degrees and
it certainly hindered climb rate, but on really soft or muddy turf
strips, I'd use a little more than 10 degrees by carefully bumping the
flap switch down in short spurts during the takeoff roll until it felt
better and got the mains off the ground, then once a positive rate of
climb was established I'd carefully retract the flaps a small amount at
a time until the airplane was happier. A lot of the other renters hated
the spring-loaded up/down flap switch in the 172L because you had to
keep it pushed up or down to run the flap motor, but I liked being able
to 'fine-tune' the flaps to what felt best in a given takeoff situation.

[[email protected]]

wrote:
> I used to rent a 172L a lot many years ago, and used 10 degrees to
> reduce the takeoff roll but for me it *increased* the rate of climb
> slightly at airspeeds between Vx and Vy.

I suspect that you were NOT at max gross weight. Were you at that
state, I expect you would find that the POH was EXACTLY correct.

We face similar problems with flaps and density altitude in Colorado.

What you experienced is exactly why we teach in the mountain flying
course to fly 10% below max gross weight... because any reduction in
load translates directly into improved performance.

Please consider coming to Colorado for the mountain flying course some
time:

http://www.coloradopilots.org/

Yes, we fly a normally aspirated C172 ("N" model) into Leadville,
Colorado at 9,927 MSL. Pattern altitude is 11,000 MSL. FUN!

Best regards,

Jer/ "Flight instruction and mountain flying are my vocation!" Eberhard

--
Jer/ (Slash) Eberhard, Mountain Flying Aviation, LTD, Ft Collins, CO
CELL 970 231-6325 EMAIL jer'at'frii.com WEB http://users.frii.com/jer/
C-206 N9513G, CFII Airplane&Glider, FAA-DEN Aviation Safety Counselor
CAP-CO Mission&Aircraft CheckPilot, BM218 HAM N0FZD, 231 Young Eagles!

[Blueskies]

> wrote in message ...
>
> http://www.coloradopilots.org/
>
> Yes, we fly a normally aspirated C172 ("N" model) into Leadville,
> Colorado at 9,927 MSL. Pattern altitude is 11,000 MSL. FUN!
>
> Best regards,
>
> Jer/ "Flight instruction and mountain flying are my vocation!" Eberhard
>


How long is the runway and what does the approach/departure zones look like?

[Ronald Gardner]

All of these post are correct, 10% for short or soft filed departure, but on
a hard surface of 2500' or more 0% works better. Air speed will climb much
faster after lift off. I fly 172 all the time and generally follow this rule
with no problems.

Michelle P wrote:

> An interesting dilemma.
> The manual for the 172 N tells you that 0-10 degrees is acceptable for
> takeoff. However it does not tell you what affect it has at low altitude
> 300 feet MSL Density altitude around 2500 MSL. It only states that it
> will have a detrimental affect at high altitude on a hot day. It also
> does not give an airspeed for Vy flaps 10 degrees.
>
> In talking to another pilot who has an 172 L has states that his manual
> says if 10 degrees flaps are used it will decrease ground roll and
> decrease climb rate. Having an overall detrimental affect.
>
> The only definitive number the 172N manual states for flaps 10 degrees
> is Vx.
>
> First hand experience seems to confirm what the 172 L manual says.
>
> What do you all think?
> Michelle

[Greg Farris]

There is another reason to use 10° flaps - training.
Many students are not learning to fly a 172, but using a 172 to learn to fly
airplanes. If you are anticipating transitioning up ASAP (as in career
oriented students) it's good to get into the habit, because your next
airplane may require flaps on takeoff, and the one after that certainly will.

I've noticed that airline pilots who also instruct in small airplanes tend to
insist on flaps on takeoff, as a matter of good habit forming. Some also call
positive rate and gear up as anticipated training.

G faris

[Thomas Borchert]

> How long is the runway and what does the approach/departure zones look like?
>

It's long and at least one departure is clear. Doing it in a 172 still
requires a lot of consideration.

--
Thomas Borchert (EDDH)

[Thomas Borchert]

Greg,

> it's good to get into the habit, because your next
> airplane may require flaps on takeoff, and the one after that certainly will.
>

If a pilot cannot (or will not) adapt to the specifics of the aircraft he/she
is currently flying, he/she has no business in any aircraft. There are so many
things different between aircraft that the idea behind that kind of habit
forming is more a danger than a benefit. Just my two cents.

--
Thomas Borchert (EDDH)

[Dave Stadt]

"Greg Farris" > wrote in message
...
> There is another reason to use 10° flaps - training.
> Many students are not learning to fly a 172, but using a 172 to learn to
fly
> airplanes. If you are anticipating transitioning up ASAP (as in career
> oriented students) it's good to get into the habit, because your next
> airplane may require flaps on takeoff, and the one after that certainly
will.
>
> I've noticed that airline pilots who also instruct in small airplanes tend
to
> insist on flaps on takeoff, as a matter of good habit forming. Some also
call
> positive rate and gear up as anticipated training.
>
> G faris

Then again one could transition up to a real airplane which of course would
have no flaps. Nor would the one after that or the one after that.

[john smith]

Greg Farris wrote:
> There is another reason to use 10° flaps - training.
> Many students are not learning to fly a 172, but using a 172 to learn to fly
> airplanes. If you are anticipating transitioning up ASAP (as in career
> oriented students) it's good to get into the habit, because your next
> airplane may require flaps on takeoff, and the one after that certainly will.

Cherokee Six calls for minimum 10-degrees flaps for all takeoffs.
If you try a no-flaps takeoff, your takeoff roll is significantly longer.

[[email protected]]

Blueskies > wrote:

> > wrote in message ...
> >
> > http://www.coloradopilots.org/
> >
> > Yes, we fly a normally aspirated C172 ("N" model) into Leadville,
> > Colorado at 9,927 MSL. Pattern altitude is 11,000 MSL. FUN!
> >
> > Best regards,
> >
> > Jer/ "Flight instruction and mountain flying are my vocation!" Eberhard
> >


> How long is the runway and what does the approach/departure zones look like?

See: http://www.leadvilleairport.com/pages/01_leadville_airport_info/leadville_airport_info.html

Runway 16/34, 6400 feet long, 75 feet wide.

After departure, "turn down-water", into the valley. Both ends of the
airport drop-offf into the (lower) valley by 200-400 feet. :-) There
are clear areas south and southwest, immediately north, then west.

ANY airplane uses up a lot more runway than you would think. :-) It
is NO uncommon at 65 degrees F for a Bonanza, with 1/2 tanks and two
people to depart on runway 34 and be at 50' AGL, climbing at 50 feet
per minute. (Read that again... over a mile of runway, barely off the
ground and barely climbing). This may be due to several factors,
including cross wind, drainage winds, and "sink" from the mountain
wave overhead and descending over the airport.

Best regards,

Jer/ "Flight instruction and mountain flying are my vocation!" Eberhard

--
Jer/ (Slash) Eberhard, Mountain Flying Aviation, LTD, Ft Collins, CO
CELL 970 231-6325 EMAIL jer'at'frii.com WEB http://users.frii.com/jer/
C-206 N9513G, CFII Airplane&Glider, FAA-DEN Aviation Safety Counselor
CAP-CO Mission&Aircraft CheckPilot, BM218 HAM N0FZD, 231 Young Eagles!

[[email protected]]

john smith > wrote:
> Greg Farris wrote:
> > There is another reason to use 10? flaps - training.
> > Many students are not learning to fly a 172, but using a 172 to learn to fly
> > airplanes. If you are anticipating transitioning up ASAP (as in career
> > oriented students) it's good to get into the habit, because your next
> > airplane may require flaps on takeoff, and the one after that certainly will.

> Cherokee Six calls for minimum 10-degrees flaps for all takeoffs.
> If you try a no-flaps takeoff, your takeoff roll is significantly longer.

All correctly stated by each... however, I suggest it is better to
"learn to fly the current aircraft proficiently in the current weather
and environment" before "attempting to learn to fly the next
aircraft".

Best regards,

Jer/ "Flight instruction and mountain flying are my vocation!" Eberhard

--
Jer/ (Slash) Eberhard, Mountain Flying Aviation, LTD, Ft Collins, CO
CELL 970 231-6325 EMAIL jer'at'frii.com WEB http://users.frii.com/jer/
C-206 N9513G, CFII Airplane&Glider, FAA-DEN Aviation Safety Counselor
CAP-CO Mission&Aircraft CheckPilot, BM218 HAM N0FZD, 231 Young Eagles!

[grubertm]

So what's the best procedure for a sand strip, 4000AGL, 50ft obstacle ?
I can see the advantage of 10 deg. flaps for a mud strip, but I am not
sure whether the increased friction due to sand is worth the decrease
in climb rate..

- Marco

[Casey Wilson]

"grubertm" > wrote in message
oups.com...
> So what's the best procedure for a sand strip, 4000AGL, 50ft obstacle ?
> I can see the advantage of 10 deg. flaps for a mud strip, but I am not
> sure whether the increased friction due to sand is worth the decrease
> in climb rate..

How about -- unbolt the wings and hire a trailer. <<G>>

[Ben Hallert]

I would guess (low time pilot warning here, wait for someone else to
comment) that soft field takeoff would be the best bet here, except
climbing out at VX instead of VY after accelerating out of ground
effect. That way, you're not dealing with the friction of the sand for
as long.

Ben Hallert
PP-ASEL

[Mike Rapoport]

Some flaps (maybe even full flaps) until airborn, accelerate in ground
effect and then climb. If you are interested in this stuff, read F.E. Potts
book on bush flying.

Mike
MU-2


"grubertm" > wrote in message
oups.com...
> So what's the best procedure for a sand strip, 4000AGL, 50ft obstacle ?
> I can see the advantage of 10 deg. flaps for a mud strip, but I am not
> sure whether the increased friction due to sand is worth the decrease
> in climb rate..
>
> - Marco
>

[David Rind]

Mike Rapoport wrote:
> Some flaps (maybe even full flaps) until airborn, accelerate in ground
> effect and then climb. If you are interested in this stuff, read F.E. Potts
> book on bush flying.
>
> Mike
> MU-2
>
>
> "grubertm" > wrote in message
> oups.com...
>
>>So what's the best procedure for a sand strip, 4000AGL, 50ft obstacle ?
>>I can see the advantage of 10 deg. flaps for a mud strip, but I am not
>>sure whether the increased friction due to sand is worth the decrease
>>in climb rate..
>>
>>- Marco

I haven't been following this thread that closely so I may have missed
something, but "full flaps"? I thought that once you got to 40 degrees
of flaps on a 172 you were just adding drag without any appreciable
reduction in stall speed. I can't see how that would get you into ground
effect any quicker....

--
David Rind

[Newps]

David Rind wrote:

> Mike Rapoport wrote:
>
>> Some flaps (maybe even full flaps) until airborn, accelerate in ground
>> effect and then climb. If you are interested in this stuff, read F.E.
>> Potts book on bush flying.
>>
>> Mike
>> MU-2
>>
>>
>> "grubertm" > wrote in message
>> oups.com...
>>
>>> So what's the best procedure for a sand strip, 4000AGL, 50ft obstacle ?
>>> I can see the advantage of 10 deg. flaps for a mud strip, but I am not
>>> sure whether the increased friction due to sand is worth the decrease
>>> in climb rate..
>>>
>>> - Marco
>
>
> I haven't been following this thread that closely so I may have missed
> something, but "full flaps"? I thought that once you got to 40 degrees
> of flaps on a 172 you were just adding drag without any appreciable
> reduction in stall speed. I can't see how that would get you into ground
> effect any quicker....
>

He said maybe. Some aircraft do use full flaps for takeoff. The Cessna
does not. You want 20 degrees to break ground quickly, accelerate to 80
mph and milk the flaps up and then climb. If you have an obstacle then
you accelerate to 60 mph with the flaps down and keep it there and climb
above the obstacle. Once above the obstacle accelerate to 80 and get
the flaps up.

[Brien K. Meehan]

For which Cessna model is that procedure recommended? Certainly not
any version of the 172.

[George Patterson]

David Rind wrote:
>
> I haven't been following this thread that closely so I may have missed
> something, but "full flaps"? I thought that once you got to 40 degrees
> of flaps on a 172 you were just adding drag without any appreciable
> reduction in stall speed. I can't see how that would get you into ground
> effect any quicker....

With an aircraft which has the ability to dump the flaps quickly (about anything
with a "Johnson bar"), you can get a remarkably short ground run by accelerating
with no flaps until just past the full flap stall speed. Drop the flaps down,
use a little elevator to yank it into ground effect, immediately put the yoke
forward to keep it a few feet above the runway, and milk the flaps up in ground
effect.

Obviously you aren't going to be able to drop the flaps that rapidly with a
172N, but the full-flaps stall speed is only 51 mph. Perhaps accelerating to
about 55 with the flaps down wouldn't incur much of a drag penalty?

Note that you *do* get a hefty drag penalty while the flaps are down, so your
distance to clear the traditional 50' obstacle is likely to be longer than a
normal takeoff.

It's a fun technique to try when there's no pucker factor involved. I used to
almost always spoil the effect by banging the tailwheel getting off the ground.

George Patterson
Give a person a fish and you feed him for a day; teach a person to
use the Internet and he won't bother you for weeks.

[George Patterson]

Brien K. Meehan wrote:
> For which Cessna model is that procedure recommended? Certainly not
> any version of the 172.

Any 172 made prior to 1964.

George Patterson
Give a person a fish and you feed him for a day; teach a person to
use the Internet and he won't bother you for weeks.

[Brien K. Meehan]

George Patterson wrote:
> Brien K. Meehan wrote:
> > For which Cessna model is that procedure recommended? Certainly not
> > any version of the 172.
>
> Any 172 made prior to 1964.

Ah, I haven't had the pleasure. Thanks!

[Bob Moore]

George Patterson > wrote
> Brien K. Meehan wrote:
>> For which Cessna model is that procedure recommended? Certainly not
>> any version of the 172.
>
> Any 172 made prior to 1964.

From my 1959 Cessna 172 Owner's Handbook:

For unusually short field takeoffs, apply 10 degrees
flaps (first notch) prior to takeoff. An alternated
procedure ofapplying 10 degrees just before the airplane
is ready to leave the ground may be used in lieu of the
above method of leaving the flaps in the 10-degree
position throughout the entire ground run. Four further
discussion of the use of wing flaps for take-off, see
page 3.2

Wing Flap Settings
For Normal takeoff Up 0 degrees
For Shortest takeoff 1st Notch 10 degrees
For Landing 2nd Notch 20 degrees, 3rd Notch 30 degrees,
4th Notch 40 degrees
-------------------------------------------------------
F. TAKE-OFF.
NORMAL TAKE-OFF.
(1) Flaps 0 degrees (retracted).
-------------------------------------------------------
MINIMUM GROUND RUN TAKE-OFF.
(1) Wing flaps 10' (First notch).
(2) Apply full throttle while holding brakes.
(3) Release brakes.
(4) Take-off slightly tail low.
OBSTACLE CLEARANCE TAKE-OFF.
(1)Wing flaps 0 degrees (retracted).
(2) Apply full throttle while holding brakes.
(3) Release brakes.
(4) Take-off slightly tail low.
(5) Level off momentarily to accelerate to best angle
of climb speed (60 MPH).
SOFT OR ROUGH FIELD TAKE-OFF WITH NO OBSTACLE AHEAD.
(1) Wing flaps 10-degrees (First notch).
(2) Apply full throttle and raise nosewheel clear of
ground with elevator control back pressure.
(3) Takeoff in a tail-low attitude.
(4) Level off momentarily to accelerate to a safe airspeed,
(5) Retract flaps slowly as soon as a reasonable altitude
is obtained. (see "Take-off paragraph on page 3-2)
----------------------------------------------------------
TAKE-OFF
Normal and obstacle clearance takeoffs are performed with
flaps retracted. The use of 10 degrees flaps will shorten
the ground run approximately 10%, but this advantage is
lost in the climb to a 50-foot obstacle. However, if 10
degrees of flaps are used in the ground runs, it is
preferable to leave them extended rather than retract them
in the climb to the obstacle. The exception to this rule
would be in a high altitude takeoff in hot weather where climb
would be marginal with flaps 10 degrees. Flap deflections of
30 degrees and 40 degrees are not recommended at any time for
take-off. General rules for flap operation during take-off
are as follows:
Don't under marginal conditions leave flaps on long enough
that you are losing both climb and airspeed.
Don't release flaps with airspeed below flaps up stalling speed.
(See stalling speed table on page 3-3). Do slowly release the
flaps as soon as you reasonably can after take-off, preferably
50 feet or more over terrain or obstacles.
-----------------------------------------------------------

[Big John]

War Story

In late 1949/early 1950 I had a P-80A on cross country headed east,
can't remember where. This early version of the P-80 had the small
engine in it and the under slung tip tanks.

It was middle of summer and I stopped at Biggs AFB (El Paso) to
refuel. Full internal and full tips.

Taxied out for a TO on R/W 21 (over 13K feet long). R/W 21 had a cross
R/W about 4K down it. I released brakes and accelerated very slowly in
the heat and altitude. When I hit the cross R/W there was a slight
bump that threw me in the air and I caught it. Wasn't accelerating
very fast so pulled the gear (flaps were still down 30 degrees) to
reduce drag.

Guess what, no climb (and no gear to land on remaining R/W). R/W
heading was over Fort Bliss and I went over it about 5 feet above the
TV antennas on the barracks (could count the elements on them) and
just missed the flag pole.

Next obstacle was the hill west of El Paso toward which I was pointed
with a snow balls chance in hell of clearing.

Used some rudder and gently skidded the nose toward the south enough
to miss the hill.

Was then over Mexico and dodging cactus and blowing sage brush.
Started milking flaps up. Would get 25 or so feet altitude and retract
flaps 2-3 degrees and when I sank would rotate the nose up to keep
from hitting ground and again fly in ground effect.

After about 20 miles into Mexico I got the flaps up and was able to
gain a little airspeed which let me climb and accelerate.

1. I was a dam good pilot in those days.
2. I was also lucky as hell which we always said was the most
important aspect of flying.

On occasion, I still wake up and see in gory color that flight in high
density altitude and temp :o( Sure made a believer out of me.

Big John
`````````````````````````````````````````````````` ``````````````````````````````


On Fri, 12 Aug 2005 16:40:49 -0000, wrote:

>john smith > wrote:
>> Greg Farris wrote:
>> > There is another reason to use 10? flaps - training.
>> > Many students are not learning to fly a 172, but using a 172 to learn to fly
>> > airplanes. If you are anticipating transitioning up ASAP (as in career
>> > oriented students) it's good to get into the habit, because your next
>> > airplane may require flaps on takeoff, and the one after that certainly will.
>
>> Cherokee Six calls for minimum 10-degrees flaps for all takeoffs.
>> If you try a no-flaps takeoff, your takeoff roll is significantly longer.
>
>All correctly stated by each... however, I suggest it is better to
>"learn to fly the current aircraft proficiently in the current weather
>and environment" before "attempting to learn to fly the next
>aircraft".
>
>Best regards,
>
>Jer/ "Flight instruction and mountain flying are my vocation!" Eberhard

[Thomas Borchert]

Grubertm,

> So what's the best procedure for a sand strip, 4000AGL, 50ft obstacle ?
>

Don't go? Seriously, you probably want to get out of the sand ASAP. After
that, you want to climb as best as you can, but that only gets important
once you have left the ground. So, do the soft field procedure to start
with.


--
Thomas Borchert (EDDH)

[Big John]

Mike

That's simple enough that every one should be able to understand.

John
`````````````````````````````````````````````````` ```````````

On Sat, 13 Aug 2005 04:05:57 GMT, "Mike Rapoport"
> wrote:

>Some flaps (maybe even full flaps) until airborn, accelerate in ground
>effect and then climb. If you are interested in this stuff, read F.E. Potts
>book on bush flying.
>
>Mike
>MU-2
>
>
>"grubertm" > wrote in message
oups.com...
>> So what's the best procedure for a sand strip, 4000AGL, 50ft obstacle ?
>> I can see the advantage of 10 deg. flaps for a mud strip, but I am not
>> sure whether the increased friction due to sand is worth the decrease
>> in climb rate..
>>
>> - Marco
>>
>

[Mike Rapoport]

I believe that some 172s only have 30deg of flaps availible. Full flaps
produce *some* additional lift even if there is a large drag increase. Keep
in mind that you are trading aerodynamic drag against the drag of the tires
in sand. On my airplanes MU-2 and Helio Courier minimium ground roll is a
function of weight, flaps and power availible.

In the Helio:

At normal density altitudes and light weights minimium ground roll is with
full flaps (40deg). This use of full flaps increases obstacle clearance
distance but reduces ground roll.

At some high density altitude and high weight the airplane won't climb out
of ground effect with full flaps without using a tremendous amount of
distance and a reduced flap setting is required.

The Helio is not that different from the 172 in terms of flaps. Both have
single slotted fowler flaps.

In the MU-2

Take off with flaps 20 uses less ground roll than flaps 5deg. Flaps 40deg
used even less distance but isn't used because the airplane becomes airborn
below Vmc and can't climb on one engine with flaps 40.

My guess is that a 172 at light weights and low density altitude will use
less runway with more than 10deg of flaps and the more powerful the engine
the more pronounced this difference. It would be interesting to see if the
new 172s have a full set of takeoff charts showing all altitudes, temps,
weights and flaps settings

Mike
MU-2


"David Rind" > wrote in message
...
> Mike Rapoport wrote:
>> Some flaps (maybe even full flaps) until airborn, accelerate in ground
>> effect and then climb. If you are interested in this stuff, read F.E.
>> Potts book on bush flying.
>>
>> Mike
>> MU-2
>>
>>
>> "grubertm" > wrote in message
>> oups.com...
>>
>>>So what's the best procedure for a sand strip, 4000AGL, 50ft obstacle ?
>>>I can see the advantage of 10 deg. flaps for a mud strip, but I am not
>>>sure whether the increased friction due to sand is worth the decrease
>>>in climb rate..
>>>
>>>- Marco
>
> I haven't been following this thread that closely so I may have missed
> something, but "full flaps"? I thought that once you got to 40 degrees of
> flaps on a 172 you were just adding drag without any appreciable reduction
> in stall speed. I can't see how that would get you into ground effect any
> quicker....
>
> --
> David Rind
>
>

[Brien K. Meehan]

Okay, this post contradicts the previous post, and the way I learned it
is more like this post.

.... but somewhere along the way, the 172 book changed from saying that
10 degrees would decrease climb performace, to indicating that it would
increase climb performance (in terms of reduced distance to clear a 50
foot obstacle).

When did the change occur? What physically changed on the aircraft?

[Bob Moore]

"Brien K. Meehan" > wrote

> Okay, this post contradicts the previous post, and the way I learned it
> is more like this post.
>
> ... but somewhere along the way, the 172 book changed from saying that
> 10 degrees would decrease climb performace, to indicating that it would
> increase climb performance (in terms of reduced distance to clear a 50
> foot obstacle).
>
> When did the change occur? What physically changed on the aircraft?

Bigger engine. When Lycoming upgraded the O-320 from 150 hp to 160 hp.
The 1959 manual that I quoted reflected the 145 hp Continental O-300.
I posted that data to refute George's post about "all 172's before
1964" used 20 degrees of flaps.

Bob

[[email protected]]

Michelle P wrote:
>
> In talking to another pilot who has an 172 L has states that his manual
> says if 10 degrees flaps are used it will decrease ground roll and
> decrease climb rate. Having an overall detrimental affect.
>
> The only definitive number the 172N manual states for flaps 10 degrees
> is Vx.
>
> First hand experience seems to confirm what the 172 L manual says.

I fly an N-model and would agree with all of the above. In a soft-field
situation there may be a moderate advantage to 10deg particularly at
lighter loadings. Based on my runnings of the numbers though the
difference looks likely to be lost in the detail.

NB- 10 degrees is standard for a 172N on floats, which I suppose is the
ultimate "soft field" situation.

-cwk.

[George Patterson]

Bob Moore wrote:
>
> I posted that data to refute George's post about "all 172's before
> 1964" used 20 degrees of flaps.

I did not mean that. What I meant was that any aircraft with manual flaps can
get the shortest ground run by dumping in full flaps just above stall speed and
hopping up into ground effect. All 172s prior to 1964 had manual flaps and can
use this technique.

George Patterson
Give a person a fish and you feed him for a day; teach a person to
use the Internet and he won't bother you for weeks.

[Mike Weller]

On Thu, 11 Aug 2005 00:26:56 GMT, Michelle P
> wrote:

>An interesting dilemma.
>The manual for the 172 N tells you that 0-10 degrees is acceptable for
>takeoff.
>What do you all think?
>Michelle

I hate giving an unscientific opinion, but piloting is a part of that.

Every Cessna (150 through 337) that I've flown just "feels better"
with 10 degrees of flaps on takeoff.

Mike Weller

[[email protected]]

Big John wrote:
> [snip]
> Taxied out for a TO on R/W 21 (over 13K feet long). R/W 21 had a cross
> R/W about 4K down it. I released brakes and accelerated very slowly in
> the heat and altitude. When I hit the cross R/W there was a slight
> bump that threw me in the air and I caught it. Wasn't accelerating
> very fast so pulled the gear (flaps were still down 30 degrees) to
> reduce drag.
>
> Guess what, no climb (and no gear to land on remaining R/W). R/W
> heading was over Fort Bliss and I went over it about 5 feet above the
> TV antennas on the barracks (could count the elements on them) and
> just missed the flag pole.
>
> Next obstacle was the hill west of El Paso toward which I was pointed
> with a snow balls chance in hell of clearing.
>
> Used some rudder and gently skidded the nose toward the south enough
> to miss the hill.
>
> Was then over Mexico and dodging cactus and blowing sage brush.
> Started milking flaps up. Would get 25 or so feet altitude and retract
> flaps 2-3 degrees and when I sank would rotate the nose up to keep
> from hitting ground and again fly in ground effect.
>
> After about 20 miles into Mexico I got the flaps up and was able to
> gain a little airspeed which let me climb and accelerate.
>[snip]

Ok, I never know whether to believe such stories or not. Here's a
similar one I liked so much that I posted it on my blog:

http://www.livejournal.com/users/clumpinglitter/25412.html

-C.

[Mike W.]

"Mike Rapoport" > wrote in message
nk.net...
> I believe that some 172s only have 30deg of flaps availible.

Yes, P series only has 30°.


--
Hello, my name is Mike, and I am an airplane addict....