172S takeoff performance

Matthew

Matthew

Touchdown! Greaser!
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Matthew
In all my extensive experience (a bit over 100hrs), I've only flown a Warrior.

I'm going to be making the transition to a 172 (specifically a 172S). I'll be getting with my CFI in a few weeks, but I'm doing my homework ahead of time.

I got a 172S information manual and have been looking through the w&b and performance charts to get a feel for the differences between the information in the PA28 book and the 172 book.

I noticed the only takeoff performance tables are for a short-field (10 deg flap) takeoffs. Did I just miss a footnote or something? Is there some information somewhere that shows distance requirements for no-flap takeoffs? Or is the implication that all takeoffs should use 10deg flaps?

Thanks,
Matt
 
I'm sure it's in there.

I normally do all my takeoffs in a 172 with 10 degrees of flaps. I see absolutely no reason for every takeoff in such an airplane to be anything but a short field takeoff. After rotation if I'm solo I'll climb out at about 55 knots until about one hundred feet. At this point I drop the nose and accelerate to Vy and remove the flaps.
 
i am mainly a warrior pilot also with only about 10 hrs in 172's and 182's and about 120 hrs TT

I always takeoff using 10 degrees of flaps, but if i recall correctly the POH for the 172S that i flew says 0-10 degrees for TO...its more of the pilots personal choice really if the plane isnt heavy or anything...i do know that you will notice that 172's get off the ground ALOT faster then warriors, and i've done a few take off's with no flaps and the plane still has very good TO performance...

but like i said..i dont have much time in cessnas either so wait for a more experienced cessna pilot before you get your final answer

Ant
 
I've mostly flown 172Sps until lately. Short field is 10 degrees of flaps. The plane comes off sooner and cleaner with 10 degrees. You can do short field with no flaps, but your takeoff roll will be a bit longer to rotation. The difference is noticeable.

Jim G
 
like i said...flaps or no flaps...the takeoff roll distance in a 172 is noticeable shorter than any warrior..
 
I don't have easy access to the POH (I'm a renter) so I got the information manual. It DOES say 'takeoff - use 0deg or 10deg flaps' but only gives the book numbers for 10deg. Just something else to talk with my CFI about.

I guess I'm just too used to the Warrion information manual/POH. it gives numbers and performance charts for almost every configuration of takeoff/landing/phase-of-the-moon that you can have.
 
Like Matthew, I'm a renter. From my recollection he's right, the POH only gives numbers for short-field with 10*. I usually use 0*, and am off quickly. I fly out of a 3300' runway, and I don't think I've ever made it even half-way down before I was off. If you're ever in a situation where you're worried about the takeoff distance you should be using short-field techniques anyway. But I agree, it would be nice to know just for completeness.

If you want a modern manual with a real dearth of information, try the Diamondstar manuals. Pretty abysmal IMHO.
 
I guess the theory is that if the runway's short enough to worry about whether you'll make it, you'll be using short field technique anyways.

Note that the 10 degree flap for short field take-off depends on the model of 172. The 172N uses no flap for short field. The various speeds, such as Vy, etc. differ between models too.

Chris
 
Anyone have any good reason not to *always* use "short field technique" in a 172? Seems to me like you might not always know when that extra altitude and runway is going to help you.
 
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cwyckham said:
I guess the theory is that if the runway's short enough to worry about whether you'll make it, you'll be using short field technique anyways.
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That's kind of what I was thinking - although it'd be nice to see in the manual that no-flaps is not something ridiculous like 200% of the 10deg flaps distance.

cwyckham said:
Note that the 10 degree flap for short field take-off depends on the model of 172. The 172N uses no flap for short field. The various speeds, such as Vy, etc. differ between models too.

Chris
Click to expand...

Yeah, this plays to the philosophy of 'know your airplane'. That's why I like to get a specific manual for each different model my FBO has me signed off. (Only 1 so far, the Warrior.)
 
jangell said:
Anyone have any good reason not to *always* use short field technique in a 172? Seems to me like you might not always know when that extra altitude and runway is going to help you.
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The only thing I would modify would be to go straight to Vy instead of climbing at Vx to get over imaginary trees. I want maximum altitude under me if I have an engine problem after take-off, and I get this with Vy, not Vx.

Chris
 
cwyckham said:
The only thing I would modify would be to go straight to Vy instead of climbing at Vx to get over imaginary trees. I want maximum altitude under me if I have an engine problem after take-off, and I get this with Vy, not Vx.

Chris
Click to expand...

I know everybody has their own style (depending on circumstances) - one of my CFI suggestions was to get the first 500-1000 feet of climb at best glide (unless Vx is really necessary). The theory being that if the engine quits, you're already at best glide speed.
 
cwyckham said:
The only thing I would modify would be to go straight to Vy instead of climbing at Vx to get over imaginary trees. I want maximum altitude under me if I have an engine problem after take-off, and I get this with Vy, not Vx.

Chris
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Well first off. Like I said. I go to Vy after about one hundred feet. The idea is that I will be a little bit lower and still be over the airport Vs. A little bit higher and further from the airport with excess airspeed. Truth be told we aren't flying big jets. Vx and Vy V-This and V-that. Just do what works for you and your airplane.

I never really have came to a solid choice about what I like to do for the climbout. Most of the time if the plane is willing to fly I'll get it in the air. From there I can either climb out slowly or accelerate in ground effect. I guess it depends on the airport.

My takeoff procedure that I run through now consists of:

Controls
Instruments
Gas
Altimeter (yes i know some people do attitude)
Runup

Doors secured

I look at the altimeter and think about the airport that I'm at. I touch the spot on the altimeter with my finger that is my "turn back" altitude This is where I'll turn back for the runway if the engine quits. Most of the time this number is set at 600 feet. Some airports that have trees / big buildings / etc I will go with a lower number / slightly different plan.

Based on the practice I've done with engine failures after takeoff I think it's critical that I react right away. The only way I can think of to ensure of this instant reacation is to think about it before the takeoff and watch the altimeter during climbout fully knowing when I cross this point. I know all throughout the takeoff what I'll do if that engine makes a funny noise or quits. Nothing to think about. Just react.

It only takes me a few seconds. I don't know if anyone else does this kind of thing. But IMO it will make one hell of a difference if the big fan does quit.
 
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Matthew said:
The theory being that if the engine quits, you're already at best glide speed.
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Interesting theory. Did the CFI also mention that if the engine quits you would still have to adjust your attidue to maintain that speed as hold the climb would quickly result in an undesired stall? :D:D

I am not sure that technique of holding best glide buys you any additional advantage.
 
I just glanced in my 172S handbook (generic one you buy as a student pilot). It only has the 10° flap/short field information.

Practically speaking, I never really needed short field technique except at Sky Manor, NJ- all the CFIs liked to so short field takeoffs there, I suppose to avoid trees.
 
jangell said:
I'm sure it's in there.

I normally do all my takeoffs in a 172 with 10 degrees of flaps. I see absolutely no reason for every takeoff in such an airplane to be anything but a short field takeoff. After rotation if I'm solo I'll climb out at about 55 knots until about one hundred feet. At this point I drop the nose and accelerate to Vy and remove the flaps.
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In many airplanes, flaps will increase the angle of climb and decrease the rate of climb. I can't say for sure that this applies to a 172S, but it's likely. OTOH if you really want every takeoff to use the same procedure for consistency and familiarity, the difference in altitude gained to the point where you've got the flaps retracted and airspeed to Vy probably isn't much more than a hundred feet if that. Of course this is assuming you are using the flaps 10 Vx. Climbing with flaps at the flaps up Vx might lose by a lot more.
 
smigaldi said:
Interesting theory. Did the CFI also mention that if the engine quits you would still have to adjust your attidue to maintain that speed as hold the climb would quickly result in an undesired stall? :D:D

I am not sure that technique of holding best glide buys you any additional advantage.
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Yeah, I know - pitch for the desired airspeed. Believe me - during my training my CFI made sure I had PLENTY of opportunity to practice that. I had engine 'failures' 2-3 times per flight. By the way, I think that trick with keeping your hand on the throttle to prevent the instructor from pulling power needs to be retaught. It needs to be pounded into students that it should be done to maintain positive throttle control, NOT to just keep the instructor from simulating an engine failure. A student that doesn't get the opportunity to 'fail' an engine just after takeoff is missing out. My CFI would still grab the throttle, but I knew why and would comply and pull power.

In the plane I normally fly, the difference between Vx (63 KIAS), best glide (73 KIAS), and Vy (79 KIAS) gives a pretty wide range to choose from. My airport has a fairly unobstructed departure area in both directions. If I'm staying in the pattern I'll use Vx just to get to pattern altitude before it's time to start descending again, if I'm going somewhere I'll use Vy (gets me farther, faster, with better visibility over the nose).

I've heard some theories that Vx puts more strain on the powerplant, and if it's going to fail, that's the time. I've heard other theories that Vx is preferred because you'll be at a higher altitude closer to the airport. I've got a feeling this is a discussion that's taken place many-a-time over the years and over countless cups of coffee.

Anyway, back to the original topic - I'll have to look a little more closely at what the 172S manual has on climb performance and other takeoff related issues. I really don't think there is anything shown shown for no-flap takeoffs. I have the Warrior book in front of me now and there are separate charts for no flap and 25 deg flap (2-notches) takeoffs. I think it's good info to have on those high DA days when a no flap takeoff may eat up so much runway that you may not have the safety margin of as much remaining runway as you would like.
 
gprellwitz said:
If you want a modern manual with a real dearth of information, try the Diamondstar manuals. Pretty abysmal IMHO.
Click to expand...

Maybe so, but they do have the data for both flapped and flapless landings! :D

Personally, I don't use short-field technique unless I need it. No particular reason. Maybe I'm too lazy to push the extra knobs around, or maybe it's just that my shortest runway at the home 'drome is 5800 feet. :yes:
 
Matthew said:
I know everybody has their own style (depending on circumstances) - one of my CFI suggestions was to get the first 500-1000 feet of climb at best glide (unless Vx is really necessary). The theory being that if the engine quits, you're already at best glide speed.
Click to expand...

The theory doesn't hold much practical advantage though because you'll still need a pitch change to maintain that speed. If best glide varies from Vy, you'll have given up altitude when the engine gives up.
 
I'll ask about that suggestion on best-glide. It's very likely I wasn't listening all the way through.
 
I almost always short field 172s, but that is probably because I learned to fly a 172R and then SP on 2300 feet. The 172SP, even with a slight tailwind, will easily get off in that space without flaps. But again I can assert that those 10 degrees shorten the roll and get you pitched up and climbing out faster. Not enough to be a safety issue on a long runway, but enough to add comfort in a short field.

And I do think Piper's graphs are more useful. Now, if they would just make graphs that an old man can read...

Jim G
 
grattonja said:
And I do think Piper's graphs are more useful. Now, if they would just make graphs that an old man can read...

Jim G
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Heh, I know what you mean. After all the pencil marks I've made, they're even tougher to read.

With my 4000ft rwy, I'd hope there won't be a problem with 0 flaps in the 172S. But I just wish there had been a table that shows that up front. I keep getting this voice in my head that says - "Verify the runway requirements at each airport as part of pre-flight planning. How can you 'know' the requirements without a chart in the POH?" Without a chart showing 0-flap takeoffs, I'd think that it is implying ALL t/o should be 10deg flaps.

I may just be making a big thing out of nothing. If you haven't figured it out yet, I'm kind of a belt-and-suspenders guy.
 
LOL - y'all should see the wonder of a book Piper made for my Cherokee 180.

You sure wouldn't be saying how great the graphs are for sure. They must have learned something as they started producing more planes.
 
I just made my first actual short field takeoff in a 172 today. 2100' grass strip in a 172N with two aboard and maybe 50 lb of stuff, so well under MCTOW. I even had some headwind, so I was well within the limits. However, as I bounced along the grass with my nose up and the end of runway marker boards fast approaching, it still added a certain element that I'm not used to on my home field which is 4600' and paved.

Chris
 
SkyHog said:
LOL - y'all should see the wonder of a book Piper made for my Cherokee 180.

You sure wouldn't be saying how great the graphs are for sure. They must have learned something as they started producing more planes.
Click to expand...

You should have seen the "Owners Manual" for my '58 Travel Air. I literally had to go through it to create my checklists (not copy, create) so I could take a check ride in it. All in all though I thought it probably was a good thing since I became very familiar with the manual.
 
jangell said:
Anyone have any good reason not to *always* use "short field technique" in a 172? Seems to me like you might not always know when that extra altitude and runway is going to help you.
Click to expand...

I guess it depends on what you mean by "short field technique". I usually don't get the option to taxi to the very end of the airport, hold the brakes, full throttle, develop full power and let 'er loose.

About 1/2 the time I fly, the tower adds "without delay". So, I do everything on the roll. On RDU's 7500' or 10,000' runways it hardly seems worth the effort. I tailor my technique to fit the situation. I also figure that short-field take-off has got to be noiser than a normal take-off and noise is the number complaint about airports. Without compromising safety, I fly as friendly as possible to those on the ground, in the air and in the plane. Not everyone enjoys the rush of a short-field take-off.
 
my shortest in the 172 was a 18-1900 foot private strip, my uncles. Had a nice 15-20 knot headwind on arrival and departure so it was really no big deal. me, leah and full fuel left us well under gross, plus this 172 had the horton STOL kit. fun though, i had always wanted to land there!

cwyckham said:
I just made my first actual short field takeoff in a 172 today. 2100' grass strip in a 172N with two aboard and maybe 50 lb of stuff, so well under MCTOW. I even had some headwind, so I was well within the limits. However, as I bounced along the grass with my nose up and the end of runway marker boards fast approaching, it still added a certain element that I'm not used to on my home field which is 4600' and paved.

Chris
Click to expand...
 
smigaldi said:
I am not sure that technique of holding best glide buys you any additional advantage.
Click to expand...

In a 172, you dont have to put the gear back down... :)
 
aha, found it.

The information I was looking for is not in the performance tables, they only show the 10deg takeoff distances. In the section NORMAL PROCEDURES/TAKEOFF/WING FLAP SETTINGS is the remark "Normal takeoffs are accomplished with wing flaps 0deg-10deg. Using 10deg wing flaps reduces the ground roll and total distance over an obstacle by approximately 10 percent."

All is right with the world.
 
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