Takeoff Technique vs Procedure

[FlySince9]

Control tower or someone waiting behind me I do the rolling thingy... Otherwise it the full power thingy

 

[Jaybird180]

It's not much fun for your prop. Full power creates a huge suction that will lift any loose debris and pull it into the prop where it will abrade the leading edges and cause nicks if the debris is bigger than dust. I like to have at least 10-20 KIAS before getting the throttles wide open on takeoff unless the field is short. And if you do that reasonably quickly it only adds about 50 ft to the takeoff.

Are you suggesting that a rolling run is safer for the prop, that there is no debris?

 

[Fearless Tower]

Are you suggesting that a rolling run is safer for the prop, that there is no debris?

Yes, particularly on some less than well maintained runways or rough fields like you might find in the backcountry. That was a big point that Sparky made - holding the brakes while at full power is alot more likely to suck up gravel and ding up your prop.

 

[poadeleted20]

Yes, particularly on some less than well maintained runways or rough fields like you might find in the backcountry. That was a big point that Sparky made - holding the brakes while at full power is alot more likely to suck up gravel and ding up your prop.

Fearless is correct that when there is loose debris like gravel on the runway, you do a lot less damage to the prop and belly if you make a rolling takeoff and advance the power slowly. Whether that's "safer" or not depends on how much performance margin you have in that particular circumstance because it's probably going to result in longer takeoff distances than the book short-field procedure.

 

[RotorAndWing]

Depends on what I'm flying.

 

[Jay Honeck]

Under 25? What are you flying?

In most non-turbo piston airplanes, MP should be within 1" of field baro at full throttle. If I only had 25 or 26 on a typical day, I would say there is a problem.

Piper Pathfinder. Normally aspirated Lycosaur O-540 B4B5.

Usually we're right around 27" of MP at full power. 25 is a nice, round number that is clearly marked on the gauge, so it's become our "abort" number over the last 9 years.

Never had to abort cuz of that yet...

 

[midlifeflyer]

Ok, this is your fault. You made me do it.

http://199.238.132.174/events/flyIn/documents/RulesandRegs2011.pdf

​

​

I'm sure you realize (heck, there might be those who don't) that's not a flight safety or engine operation rule but a competition rule so everyone in the competition is being measured by the same standards.

 

[flyingron]

If you're on a field with lose material (decomposing asphalt, gravel, rocks) you do NOT want to stand on the brakes and put the power in or you're going to suck all that junk into your prop. Unless the field is short minimum power to get rolling and ease it in.

 

[TangoWhiskey]

"If the engine quits before 500' AGL, we're landing straight ahead. Above 500' we can turn enough to land in the golf course. At 800' we can return to the runway."

Similar, but I always quote those numbers as MSL, visualizing the big white hand at +500/+1000 from where it is right now. This keeps it relative to the airport I'm departing, and no math... If that engine coughs during takeoff, a quick glance at the big white pointer while pushing the nose over tells me if I've met my threshold for action A, B, or C.

 

[kgruber]

Depends

 

[bob_albertson]

Third question: Does abort procedure enter your mind when you choose which technique to use?

No because we have a balanced field length at every airport we go to in the Cessna

 

[p1l0t]

No argument on using all the runway or even holding the brakes before power up other than the increased risk of sucking debris up into the prop.

However I disagree about climbing out at the best angle of climb speed Vx (perhaps that isn't what you meant) as normal. You should only climb at Vx if you need to clear an obstacle otherwise Vy is much safer. Get your CFI and try some power failures at 10, 25, and 50 feet if you want to see why. Let him know what you are doing before cutting the power if you don't want to bend sheet metal.

Brian
CFIIG/ASEL

I don't know how concerned about nailing Vx I would be with all the runway in the world, but then again at Vx you have that much more chance of getting back down from 50 feet and still having some runway left. IF you get the nose down right away instead of going through the denial stage... BTW I am a CFI and I do introduce my students engine-outs at various altitudes/attitudes.

 

[Geico266]

OK, I like throttling up before brake release. I get a kick in the pants from the 260 ponies up front. Its just plain fun.

Picking up rocks is not a good idea with a prop.

 

[Capt. Geoffrey Thorpe]

I know where the FAA is coming from with their technique. It's easily applied to all aircraft, so everyone is teaching the same thing, and all evaluated on the same thing. It does not however get the shortest distance, over other techniques. Shorter than standard take off, yes. Shortest, no.

Ok, did a 'speriment today.

Wind 160 at 5
Temperature 22, dew point 15
Altimeter 30.35
Runway 17 at ONZ - 590' MSL

1050 pounds takeoff weight

Stop with the tail right on the end of the runway - Apply brakes, run up the mighty Rotax 912, and go. Ground run 196 feet.

Roll in from a moderate taxi speed, start pushing power in as I turn - as much as I felt comfortable with. Ground run (measured from the end of the runway) about 165 feet.

So the running start got me off 31 feet sooner in spite of the fact that I didn't get full power in during the turn.

I didn't have a good way to estimate the difference in distance to get to 50 feet AGL. But it was about 800 - 900 feet for both cases.

 

[Tom-D]

...except that you're wasting runway while the engine is spooling up. I'm pretty sure the manufacturers have tested this and determined that a full power run-up before brake release gets the shortest takeoff distance without compromising safety by attempting a high-speed turn onto the runway.

We assume you stopped at the hold short line, when cleared for take off, your roll starts at the hold short line, and doing it this way the aircraft should be rolling at 15-20 miles per at the center line of the runway where many pilots stop and go full power.

on the roll has the advantage of the speed carried thru the stop.

 

[p1l0t]

Ok, did a 'speriment today.

Wind 160 at 5
Temperature 22, dew point 15
Altimeter 30.35
Runway 17 at ONZ - 590' MSL

1050 pounds takeoff weight

Stop with the tail right on the end of the runway - Apply brakes, run up the mighty Rotax 912, and go. Ground run 196 feet.

Roll in from a moderate taxi speed, start pushing power in as I turn - as much as I felt comfortable with. Ground run (measured from the end of the runway) about 165 feet.

So the running start got me off 31 feet sooner in spite of the fact that I didn't get full power in during the turn.

I didn't have a good way to estimate the difference in distance to get to 50 feet AGL. But it was about 800 - 900 feet for both cases.

+1 for that! I have always thought holding the brakes and running up was the best way to clear an obsticle but now I wonder. Of course I guess much of that depends on how safe you feel with the turn and also the airplane. Not so much the airplane for the turn, but different horsepower/weight/rotation/climb speeds.. Next time I get the chance I'll try it too.

<---<^>--->

 

[dmccormack]

The biggest advantage of the brake then Full power technique is a the momentary assessment that the engine is in fact making full power.

If you're on a really short strip you need to know that before you release brakes.

I also prefer this method if the airplane has been sitting (don't they all?)

 

[TripleZ]

The biggest advantage of the brake then Full power technique is a the momentary assessment that the engine is in fact making full power.

If you're on a really short strip you need to know that before you release brakes.

I also prefer this method if the airplane has been sitting (don't they all?)

This ^^^^^^

The rolling start will be better IF you can carry enough speed off the taxi way to make up the difference. Wet, icy, little bit of snow, your turn is so slow your really not carrying speed.

IF the taxi way enters at the beginning of the runway. With short strips, this isn't always the case.

Personally on long runways, I'll roll onto center and throttle up smoothly. Moderately short, I'll turn so I get as much runway as possible, hold the brakes a bit, smooth power on, but release brakes before I reach full throttle.

Short field, brakes, full power, release. I always make sure I'm making power. Sometimes you have to lean a bit.

 

[EdFred]

The biggest advantage of the brake then Full power technique is a the momentary assessment that the engine is in fact making full power.

If you're on a really short strip you need to know that before you release brakes.

I also prefer this method if the airplane has been sitting (don't they all?)

This ^^^^^^

The rolling start will be better IF you can carry enough speed off the taxi way to make up the difference. Wet, icy, little bit of snow, your turn is so slow your really not carrying speed.

IF the taxi way enters at the beginning of the runway. With short strips, this isn't always the case.

Personally on long runways, I'll roll onto center and throttle up smoothly. Moderately short, I'll turn so I get as much runway as possible, hold the brakes a bit, smooth power on, but release brakes before I reach full throttle.

Short field, brakes, full power, release. I always make sure I'm making power. Sometimes you have to lean a bit.

Because you can't run it up to full power (and then reduce it back down to make the turn) before you enter the runway, or before you make the 180 if the taxiway isn't at the end?

Let's say it doesn't make full power in both cases. From the holding of the brakes procedure, you cut power to idle, and taxi back to the ramp. If you are rolling, you cut power to idle, and taxi back to the ramp. 70% by 50% and all that stuff. If it's icy, holding the brakes isn't going to do anything anyway.

Physics....study up.

 

[p1l0t]

LOL short-field icy takeoffs... Have not tried that one yet.

<---<^>--->

 

[EdFred]

LOL short-field icy takeoffs... Have not tried that one yet.

<---<^>--->

Yeah, those don't happen. The other thing about icy field take offs is you DON'T put it on the center line, nor do you line up with the center line.

 

[dmccormack]

Because you can't run it up to full power (and then reduce it back down to make the turn) before you enter the runway, or before you make the 180 if the taxiway isn't at the end?

Let's say it doesn't make full power in both cases. From the holding of the brakes procedure, you cut power to idle, and taxi back to the ramp. If you are rolling, you cut power to idle, and taxi back to the ramp. 70% by 50% and all that stuff. If it's icy, holding the brakes isn't going to do anything anyway.

Physics....study up.

Prop damage -- word.

I use the recommended runup procedure which is always some lower power setting (1700 or 1500 or thereabouts).

Also, many taxiways are near other things (houses, sheds, equipment, roads, other airplanes) and even feeble 65 or 85 or 100 HP engines cause enough prop wash to be annoying or even harmful.

So, on a very short field or after a long time sitting in the hangar, my technique is:

After a 1500 RPM mag and carb heat check I taxi out to the edge of the runway to use every foot available, get centered, hold brakes, smoothly apply full power, confirm power and oil pressure (this takes less than a second), then release brakes.
​

The laws of physics remain undisturbed.

 

[dmccormack]

Yeah, those don't happen. The other thing about icy field take offs is you DON'T put it on the center line, nor do you line up with the center line.

I use the centerline in the Chief -- off the left side window.

When it's snow-covered I guess.

 

[EdFred]

Prop damage -- word.

I use the recommended runup procedure which is always some lower power setting (1700 or 1500 or thereabouts).

Also, many taxiways are near other things (houses, sheds, equipment, roads, other airplanes) and even feeble 65 or 85 or 100 HP engines cause enough prop wash to be annoying or even harmful.

So, on a very short field or after a long time sitting in the hangar, my technique is:

After a 1500 RPM mag and carb heat check I taxi out to the edge of the runway to use every foot available, get centered, hold brakes, smoothly apply full power, confirm power and oil pressure (this takes less than a second), then release brakes.
​

The laws of physics remain undisturbed.

Well if you want to have a longer ground roll, be my guest.

 

[COFlyBoy]

Picking up rocks is not a good idea with a prop.

This seems to be a theme. I don't usually fly from gravelly runways. In fact I think most of the prop erosion/nicks that I have experienced has been on the taxi to the runway, not on the runway itself.

Also, this seems to be an OWT. Anyone have any data on how much more damage you are likely to incur if you throttle up before rolling. (I'll bet the answer is no)

For me to get rolling requires at least 1500RPM which can pick up rocks too.

 

[dmccormack]

This seems to be a theme. I don't usually fly from gravelly runways. In fact I think most of the prop erosion/nicks that I have experienced has been on the taxi to the runway, not on the runway itself.

Also, this seems to be an OWT. Anyone have any data on how much more damage you are likely to incur if you throttle up before rolling. (I'll bet the answer is no)

For me to get rolling requires at least 1500RPM which can pick up rocks too.

OWT? You stay in one place, the prop is spinning creating a low pressure right above the spot of ground. If there is debris there, it will come straight up into the low pressure and the prop.

If you are moving across the ground, the ascending debris is likely to be pulled up behind the spinning prop -- the faster you roll, the further back. In addition you're not over one spot long enough to create the low pressure vacuum required.

1500 RPM just to roll? You fly out of the Lebrea tar pits?

 

[dmccormack]

Well if you want to have a longer ground roll, be my guest.

"Longer" is relative.

Longer than what? A rolling start? Sure -- if you're rolling along at 10 MPH or more and make the turn you'll have more energy in the bank.

That trick has limited usefulness in a TW unless you're really good. And a bit lucky.

 

[RoscoeT]

I gotta remember that...

FAA: Why didn't you do it by the book?
Me: Well, EdFred said on the internet that he tested it himself and found he did better his way.

Well Ron, you can be by the book in your CFI teachings, but the rest of us will do what works best for us, even if it does in fact...gasp...conflict with the the "FAA method". BTW, I didn't know the FAA was such an expert on short field techniques that must be used when your life depends on it. You and the FAA should go up to Alaska and teach those bush pilots a thing or two about technique. Those guys aren't exactly by the "FAA book".

And I too, do not believe that running the plane up to full power while holding the brakes gets you off any faster than just getting the power in quickly. Cavitating propellors don't make max thrust. It's just pointless, regardless of what the "book" says. And you're more likely to pull crap into your prop doing that. If it makes you feel cool, then go right ahead. I guarantee anybody doing the brake-and-release takeoff is nowhere close to needing max. performance anyway.

 

[Anthony]

It takes less energy to accelerate a moving object than it does a stationary object. Moment of inertia and all. I roll, even on a short field. I roll on a soft field, I roll on a normal field...

That's how I was taught. When I took the CPA Mountain Flying Course, we turned off the alternator, started the take off roll essentially on the taxiway, got speed up then turned onto the runway and took off. The power required to overcome the intertia of standing still is already passed, and its better to already be rolling at a good pace when you hit the runway. And you know I LIKE a lot of runway.

 

[jesse]

The reason the book suggests you start from a stop is quite simple - that is the only way they're going to be able to give you performance tables. You'll get a consistent result that can be known before-hand via the book.

Starting from a roll has too many variables. It doesn't mean you won't be able to beat the book starting from a roll it simply means there is no way to WRITE the book that way. Some people might beat the book, others may not, lots of technique involved.

If you think the aircraft manufacturer thinks starting from a complete stop will give a faster result, well, you need to learn to think.

If you think that the manufacturer has any choice but to base the tables from a stop, well, you need to learn to think.

Sometimes you might beat the book. Sometimes you might not. There are a lot of factors that'll change that. At the end of the day you need to understand why the book has you start from a complete stop and then decide how you're going to handle your takeoff given the conditions and all the variables.

 

[Anthony]

I was taught that you brought up full power prior to break release to make sure the engine, and other systems were operating properly for a short field take off. I just watch the gauges while rolling.

 

[dmccormack]

Well Ron, you can be by the book in your CFI teachings, but the rest of us will do what works best for us, even if it does in fact...gasp...conflict with the the "FAA method". BTW, I didn't know the FAA was such an expert on short field techniques that must be used when your life depends on it. You and the FAA should go up to Alaska and teach those bush pilots a thing or two about technique. Those guys aren't exactly by the "FAA book".

And I too, do not believe that running the plane up to full power while holding the brakes gets you off any faster than just getting the power in quickly. Cavitating propellors don't make max thrust. It's just pointless, regardless of what the "book" says. And you're more likely to pull crap into your prop doing that. If it makes you feel cool, then go right ahead. I guarantee anybody doing the brake-and-release takeoff is nowhere close to needing max. performance anyway.

If you were actually reading instead of simply reacting, you would see that no one is arguing a rolling takeoff is less effective than a brake-full power-release brakes takeoff.

I've posted several times now that my preference is to do a full runup with brakes, then release after the airplane has been sitting or I want to use every inch of a field.

I fly a 1940 Chief -- tiny wheel in back. I have rolled onto the runway many times and then gradually applied power once I'm straight. Am i doing this to gain 13.002 feet earlier departure?

No -- I do this when I'm confident the engine is making max power and I have plenty of runway before me.

When it's been sitting or it's cold or I feel like it I taxi all the way to the end of the runway, get centered up, hold what little brakes I have, apply full power, confirm 2200 RPM static RPM, confirm oil pressure, and release.

I don't do this on turf runways I've flown since they are usually short and covered in grass -- so if I come to a full stop I get bogged down in the grass. So I roll.

The FAA PTS recommends the brakes-full power-release technique since it's easily tested. That works for me.

 

[COFlyBoy]

OWT? You stay in one place, the prop is spinning creating a low pressure right above the spot of ground. If there is debris there, it will come straight up into the low pressure and the prop.

If you are moving across the ground, the ascending debris is likely to be pulled up behind the spinning prop -- the faster you roll, the further back. In addition you're not over one spot long enough to create the low pressure vacuum required.

1500 RPM just to roll? You fly out of the Lebrea tar pits?

I guess I don't disagree with the "it stands to reason" approach here, but I'd like to know what the actual cost in damage to my prop is for doing full power on the brakes. I suspect it is low to negligible.

I do have a few nicks that have been filed out of my prop, but I have no way of knowing where they happened. I think most of them probably happened off the runway, since the ramps, weeds and taxiways I operate on have far far far more debris than any of the runways.

The 1500 RPM was just thrown out there. It definitely takes more than 1000RPM to get rolling. I'm not sure exactly how much.

 

[TripleZ]

Because you can't run it up to full power (and then reduce it back down to make the turn) before you enter the runway, or before you make the 180 if the taxiway isn't at the end?

Let's say it doesn't make full power in both cases. From the holding of the brakes procedure, you cut power to idle, and taxi back to the ramp. If you are rolling, you cut power to idle, and taxi back to the ramp. 70% by 50% and all that stuff. If it's icy, holding the brakes isn't going to do anything anyway.

Physics....study up.

If its icy, you aren't going to be able to make that turn onto the runway with any kind of speed to make a difference. To benefit from the rolling start, you need to carry the most speed possible off the taxi way. Worst case on an icy runway, you turn too fast and end up sliding into a snow bank.

For holding the brakes, true they might not hold that long, but if the plane starts sliding.....I'm already pointed down the center line. Worst case, I release the brakes and do a normal takeoff.



I'm not against the roll-on start. If its a short field, with a high speed taxi-way entry, you can bet I'm going to carry as much speed off the taxiway as possible. At that point, its just a curved runway. (Think short field grass).

But as others have pointed out.... when I really need to make the short field, If I follow the book procedure, I should be able to hit the numbers every time. Its about consistency.

 

[EdFred]

Its about consistency.

And I consistently beat my dead stop distances with the rolling start on grass, on dry pavement, on wet pavement. And no, you don't need the most speed possible. Physics. Learn it. Love it.

 

[denverpilot]

That's how I was taught. When I took the CPA Mountain Flying Course, we turned off the alternator, started the take off roll essentially on the taxiway, got speed up then turned onto the runway and took off. The power required to overcome the intertia of standing still is already passed, and its better to already be rolling at a good pace when you hit the runway. And you know I LIKE a lot of runway.

I'll throw in here that none of the above is in the official CPA text I'm looking at hete, nor taught by my "volunteer" instructor.

They're pretty clear nowadays that you're not doing backcountry work here and that the book numbers (stopped not rolling) are the criteria for the go/no-go.

I think your instructor embellished their curriculum a bit. But I can call Walt and ask him if it's in there if you like.

Turning off the Alternator? I get the concept but that's a bit extreme unless you were flying a seriously underpowered aircraft for the mountain mission. Wow.

 

[dmccormack]

Wow -- folks love to conflate different topics here!!



Short Field takeoff technique assumes you have limited working room. You want to use as much runway in front of you as possible.

If you have the room to roll on (a continuous turn from taxi position to runway) and can maintain positive control without over stressing gear -- have at it.

Soft Field takeoff technique assumes you're taking off from grass or dirt which may have soft spots. You must continually roll to avoid getting bogged down.

Full power runup with brakes on makes sense if you want the time to confirm full power. This is doubly critical for a short or narrow (or both) field where it's so tight you can't afford a glance at the oil pressure once rolling or 150 RPM less than normal if you're going to make it out.

These are three different topics.

 

[p1l0t]

Wow -- folks love to conflate different topics here!!



Short Field takeoff technique assumes you have limited working room. You want to use as much runway in front of you as possible.

If you have the room to roll on (a continuous turn from taxi position to runway) and can maintain positive control without over stressing gear -- have at it.

Soft Field takeoff technique assumes you're taking off from grass or dirt which may have soft spots. You must continually roll to avoid getting bogged down.

Full power runup with brakes on makes sense if you want the time to confirm full power. This is doubly critical for a short or narrow (or both) field where it's so tight you can't afford a glance at the oil pressure once rolling or 150 RPM less than normal if you're going to make it out.

These are three different topics.

Unless...

<---<^>--->

 

[EdFred]

The only difference between my short field and soft field technique is pressure on the nose wheel.

If my short field technique allows me to take off 100' shorter but I have to give up 5' behind me, I will take the 95' advantage over the FAA way. But you're telling me that you would rather have the 5 extra feet of runway in front of you, even though you won't be airborne for another 100 feet?

Go for it.

 

[dmccormack]

The only difference between my short field and soft field technique is pressure on the nose wheel.

If my short field technique allows me to take off 100' shorter but I have to give up 5' behind me, I will take the 95' advantage over the FAA way. But you're telling me that you would rather have the 5 extra feet of runway in front of you, even though you won't be airborne for another 100 feet?

Go for it.

You gain 100 feet by rolling on at what speed and on what surface?