Angle, or Vx/Vy on takeoff?

Fffflats said:
How deep do you want to go?
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Not that deep. The OP probably has less than 5 hours, judging by the naivete of the question. If the CFI made any mistake, it might be in letting the OP even touch the controls on a takeoff so early in training. She ought to be pointing out where to look to establish a stable climb attitude as she demonstrates proper technique. The OP needs to have time to nail down the correct site picture without being distracted by trying to fly an airplane before learning how to do it.
 
Nah, this is just a good discussion. Theres clearly a million ways to skin this cat.

What the OP needs FIRST is WHAT EVER it takes so that it makes sense to HIM, to accomplish the goal… dont stall, dont run into things.

THEN he needs what ever it takes to translate what makes sense to him into ACSese to appease a DPE.

For some, just teaching the ACS makes it one neat tidy step. For others there’s a couple layers of translation.

Being a Navy pilot, am I the best? Nope. But I AM THE BEST IN THE WORLD at learning how they want to teach.

How many hours to solo? How many layers of translation required? It’s a fair way of looking at it.

For some I will teach a degree of pitch, and I’ll do it a thousand times for a hundred situations… others I just say climb like heck, don’t stall, when clear climb at something that makes sense…. ONCE.

This is merely a discussion on various ways to get there, and various ways it makes sense to various minds.
 
dtuuri said:
If the CFI made any mistake, it might be in letting the OP even touch the controls on a takeoff so early in training.
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Wait, what?

My very first takeoff on my first flight was fully under my control, with the CFI telling me what to do.

If a CFI is still on the controls at 5 hours, one of the two parties needs to be fired.
 
Tools said:
Nah, this is just a good discussion. Theres clearly a million ways to skin this cat.
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Perhaps, but only one of them will satisfy the DPE in accordance with the ACS. IMO, teaching a pre-solo student pilot anything other than the ACS-prescribed terminology and methodology is doing them a disservice by confusing them and setting them up for a failed checkride.

I had one CFII tell me to do (or not do) three specific things that were in direct contradiction to the ACS and would have gotten me a failed checkride. When I'm working towards a cert, I don't care how the airlines or military do things - I need to know what the DPE expects me to say, and how he/she expects me to fly.

But yeah, it's a good discussion.
 
MauleSkinner said:
Beechjet 400. Sounds like the Hawker would do it, too, based on your post. It’s been 15 years since I flew those, so I don’t remember.
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It'll definitely get there eventually, but not by 75 AGL.

MauleSkinner said:
Good question…the 7.5 degrees pitch for GA in the 400 is a carryover from the Diamond, which had 400 lbs less thrust per side. In the 400A with the same engines as the 400, they bumped GA up to 10 degrees, which gives you Vac on one engine with flaps 10 and gear up.
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It's funny what quirks some airplanes have because they got certified in one configuration and tested like crazy, then something changes that would completely change the results of the tests and the FAA is like "Meh, whatever."

Tools said:
THAT is precisely what I was talking about. It’s CALCULATED.
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Yes, by the engineers. I've never seen one that is calculated in real time.

Tools said:
I’m practically certain in the hand flown arena we are taught a set pitch for the go. If after all is said and done (flaps less, two rates, gear…) if you are less than v2, pitch down for it; if v2 to v2 plus 10, maintain; if greater than v2 plus 10, pitch up for v2 plus 10.
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Martin Pauly said:
In another article, John submits:

"My pet peeve in climbs is using too low an airspeed. One famous training organization insists on using 95 knots to 1,000 feet AGL in a Bonanza, most of the twin operators push for a climb at or near the blue line, and virtually all the transport operators use a V2+10 climb with all engines operating. I think it’s stupid to climb that slowly in any airplane (including jets, just so I offend everyone here!) once actual obstacles are cleared."
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dmspilot said:
So he must have never flown for a transport operator then.
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This was the prevailing technique at some point in the olden days. It's part of what caused the American 191 crash - They were flying OK until the FO, who was PF, pitched back up to slow to V2+10 and the slat-less left wing stalled. The current best practice is to maintain whatever speed you have. Deakin had been flying the 747 for a decade before AAL191 crashed, and retired 27 years ago, so there's a good chance that this was true when it was originally written.

Boom! said:
4
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So, do you have more hours in the airplane, or more hours in this thread at this point? :rofl:

Maybe you can get us back on track by telling us what your CFI says now!
 
Roger Wilco said:
I see. Well, what's the prevailing in these new days?
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Hold whatever airspeed you have (as long as it's above V2, of course). Don't slow down if the plane is flying and climbing OK where it is.

IIRC, V2+10 on AAL191 was one knot below the calculated stall speed with no slats for their weight that day, so if the FO wouldn't have come back to V2+10 they might have had a chance. He did exactly what he was trained to do, though, certainly not casting stones here.
 
dtuuri said:
Your taildragger or his?
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Don't care. Pretty sure I would learn a ton from him driving a wheelbarrow. Old guys who used to land on boats are high on my list of people who know stuff.
 
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Curious, this obsession with flight directors and transport category takeoff performance in a thread by a new student learning to fly a 152. But here I go...

With regard to transport category aircraft, Deakin was correct in that V2 + 10 is not the optimum climb speed for a big jet in the takeoff configuration. The speed V2 + 10 (or, on some aircraft, + 15) is part of a standard performance solution that guarantees sufficient climb gradient to meet the minimum required should a thrust loss occur at V1. Any speed from V2 all the way up to the maximum speed for the flap configuratin could be used. There are YouTube videos of airliners putting on a little airshow by lifting-off, accelerating in ground effect while retracting the flaps, then pitching up to 25 or 30 degrees and roaring off into the wild blue yonder. The less dramatic, standard takeoff profile calls for maintaining an initial climb speed of V2 + 10, which is a compromise that results in reduced climb performance but also results in less horizontal distance than that required to accelerate to an aerodynamically optimum climb speed. Therefore, by initially climbing at V2 + 10 the minimum climb gradient will be met or exceeded and the total distance to reach the end of the most restrictive climb segment (typically the 2nd segment, which ends upon reaching 400' agl) will be less than if the airplane had first been accelerated to a faster climb speed. Boring, I know, but recommended by 4 out of 5 doctors.
 
flyingcheesehead said:
Hold whatever airspeed you have (as long as it's above V2, of course). Don't slow down if the plane is flying and climbing OK where it is.

IIRC, V2+10 on AAL191 was one knot below the calculated stall speed with no slats for their weight that day, so if the FO wouldn't have come back to V2+10 they might have had a chance. He did exactly what he was trained to do, though, certainly not casting stones here.
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I see what you're getting at, but I'm not sure that's what Deakin was referring to.

With regard to AA 191, their procedure at the time called for a climb at V2 to 800' agl, (many operators use 800' instead of 400' as the end of their 2nd segment). Since the engine failure and separation occurred between V1 and V2 (and this is key), the correct speed to fly, according to AA's procedure, was V2 to 800' agl, and that's what the flight director was programmed to command. The F/O apparently did not pitch-up aggressively during rotation, resulting in the airplane reaching a speed of 172 knots, but with no way of knowing that the left wing was aerodynamically compromised, he complied with AA's procedure by correcting with an increase in pitch, following the FD pitch cue to 14 degress which resulted in a deceleration toward V2 of 153. Then the left wing stalled. Just an added note that the speed that existed at the time of engine failure was less than V2.

Current procedures (and flight director programming) for at least some fleets at some airlines looks something like this:

1. Thrust loss detected at V1 up to V2 + 10: maintain V2 + 10.
2. Thrust loss detected at > V2 + 10 up to V2 + 15: maintain existing speed.
3. Thrust loss detected > V2 + 15 up to V2 + 25: pitch up to achieve and maintain V2 + 15.
4. Thrust loss detected > V2 + 25: "what was that?"

So you're correct in that we don't do it thataway no more. In fact, AA's own procedure was changed to V2 + 10 shortly after that accident. I don't know what procedures and speeds other airlines were using at the time.
 
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Ed Haywood said:
Don't care. Pretty sure I would learn a ton from him driving a wheelbarrow. Old guys who used to land on boats are high on my list of people who know stuff.
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Oh, no doubt! But just because you've done it and I've done it and probably every other instructor has done it too doesn't make it efficient or wise. I now would prefer to demonstrate where the student gets important clues about aircraft attitude before arriving at the practice area where the student will have a head start on learning the four fundamentals. Saves wasting time for basically, kicks. If that doesn't sound worth it, maybe the attached will, :dunno:: Btw, Rod Machado's favorite syllabus doesn't have the student try a take off until lesson #3: https://rodmachado.com/blogs/learning-to-fly/18063351-the-minimalist-syllabus
 

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My best way of explaining it is you want to do the initial 5-10° after rotating, then sorta maintain that and let the plane build some airspeed after that to get to Vx/Vy and then pitch for that. If you immediately try to pitch for Vx/Vy after rotating, you’re just gonna land again or be gliding down the runway… you have to kinda let the plane speed up. As far as Vx vs Vy, that depends on the conditions of and what kind of takeoff. Which take what I say with a grain of salt. I’m just a low time pilot
 
bdoss2006 said:
My best way of explaining it is you want to do the initial 5-10° after rotating, then sorta maintain that and let the plane build some airspeed after that to get to Vx/Vy and then pitch for that. If you immediately try to pitch for Vx/Vy after rotating, you’re just gonna land again or be gliding down the runway… you have to kinda let the plane speed up. As far as Vx vs Vy, that depends on the conditions of and what kind of takeoff. Which take what I say with a grain of salt. I’m just a low time pilot
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If you rotate to and maintain the attitude that will give you Vx or Vy, the airplane will accelerate to that speed. No “sorta” required.
 
MauleSkinner said:
If you rotate to and maintain the attitude that will give you Vx or Vy, the airplane will accelerate to that speed. No “sorta” required.
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Yes, but it will reach that speed faster if you hold it level for a bit after lifting off.
 
iamtheari said:
There always is. While there is a chance that there are CFIs out there teaching students that Vx and Vy don’t matter and they should climb by reference to the attitude indicator alone, there is a much greater chance that the CFI said something smart that the low-time student pilot misunderstood, either on its own or in relation to other lessons. It’s like the game of Telephone except that the last person before us in the chain is repeating words that he just heard for the first time.

For those who think the CFI is an idiot and should be fired immediately, how do you transition from Vr to Vy? Is there something fundamentally stupid about giving a student a starting pitch angle to use for that transition?
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Yeah, you look outside for pitch, however.
 
Kenny Phillips said:
Yeah, you look outside for pitch, however.
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I do. You do. The OP's instructor probably does, too. In post #1, the OP didn't mention the attitude indicator. That seems to have been assumed by many people in this thread, but it's not there. (And if it were, I'd still apply a healthy grain of salt for all the reasons mentioned above.)
 
While on a checkride you may need to demsonstrate some specific speed within tolerances, at this point just feel the airplane. Unless you are training at a 1500’ strip, roll, rotate, accelerate, and feel the pitch that provides the best climb rate. It’ll be pretty close to Vy but start with feeling then looking.
 
Dana said:
Yes, but it will reach that speed faster if you hold it level for a bit after lifting off.
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MauleSkinner said:
How fast do you need to get there?
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Heh... I still have my takeoff performance charts on screen thanks to @Jim K's CO thread, and I just noticed that it has not only a takeoff speed but a "speed at 50 feet" published. Not that I've ever paid attention, clearly...

FWIW, at MGTOW it says takeoff speed is 66 KIAS and speed at 50 feet is 80 with a table that roughly follows the square root law. Vx is 85 and Vy is 105. Early in the departure I am using the energy added by the engine to increase both speed and climb rate.
 
flyingcheesehead said:
Heh... I still have my takeoff performance charts on screen thanks to @Jim K's CO thread, and I just noticed that it has not only a takeoff speed but a "speed at 50 feet" published. Not that I've ever paid attention, clearly...

FWIW, at MGTOW it says takeoff speed is 66 KIAS and speed at 50 feet is 80 with a table that roughly follows the square root law. Vx is 85 and Vy is 105. Early in the departure I am using the energy added by the engine to increase both speed and climb rate.
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Ah, reading the flight manual to know how to fly the airplane! For shame! :biggrin:
 
Yeah when we all have digital airplanes with always in-spec aerodynamics and engine performance, those POH numbers will be 100% accurate. Till then, they are estimates; close but not absolute. Experience and gouge will count for something till then.
 
Typical POA response to a softball question.

What's wrong with the simple approach of Vx if obstacle clearance is primary, Vy otherwise until at a safe altitude in order to get away from the ground as fast as practical? ("Safe altitude" is a good discussion to have with the instructor when talking about mechanical issues during takeoff and avoiding the impossible turn.) If one becomes an owner or just cares about the health of your airplane engine, the concept of a cruise climb or engine-cooling climb can be discussed and used during flights.

When it comes to Vx and Vy, there is no one attitude that will capture that in all airplanes. Teaching it that way in primary training might inculcate improper understanding. In instrument training, you would "learn the numbers" by noting what attitude and power setting is required to set up a desired flight regime. For Vx and Vy in a fixed pitch airplane, one would apply full power and adjust the airspeed accordingly, then note what attitude is appropriate in that airplane. An especially aware student pilot might note what kind of rpm and climb rate is generated at Vy. If those numbers decrease significantly below "normal" on takeoff that is a red flag. I've caught an otherwise silent mag failure during takeoff that way.
 
MauleSkinner said:
My follow-up question is, “how close are they?”
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You tell me. How dirty is your airplane? How many trailing edges are dinged? How well are the flight controls rigged? How accurate is your airspeed indicator? ....your altitude indicator? Your tachometer? How much of that "rated" power is actually getting delivered to your prop? For that matter, how straight is your prop? Is it the same prop the POH numbers were based on? Too many variables to say.
 
@MauleSkinner, here's a good starting point for conducting some of your own tests. Why don't you try some of this out on your aircraft and let us know how close the numbers are. My bet is you'll find it would take a lot more patience, and a lot more skill than most of us here have in order to get much better than a range of plus or minus some percentage of the POH numbers. http://www.sonex604.com/flight_testing2.html (PS: I have done a little of this. Its not as easy or as precise as you'd think.)
 
wilkersk said:
You tell me. How dirty is your airplane? How many trailing edges are dinged? How well are the flight controls rigged? How accurate is your airspeed indicator? ....your altitude indicator? Your tachometer? How much of that "rated" power is actually getting delivered to your prop? For that matter, how straight is your prop? Is it the same prop the POH numbers were based on? Too many variables to say.
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So your statement that the numbers are “close” is totally without basis.

As a point of reference, no one on a Flight Review who has ever told me “I always have at least 50% more runway than the book” has ever been able to takeoff or land within 150% of the book distance.
wilkersk said:
@MauleSkinner, here's a good starting point for conducting some of your own tests. Why don't you try some of this out on your aircraft and let us know how close the numbers are. My bet is you'll find it would take a lot more patience, and a lot more skill than most of us here have in order to get much better than a range of plus or minus some percentage of the POH numbers. http://www.sonex604.com/flight_testing2.html (PS: I have done a little of this. It’s not as easy or as precise as you'd think.)
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In CAR3/Part 23 airplanes, examples include King Air 90s where my takeoff distance was normally within 200 feet of the published 50 foot distance, and in my Maule it was within 100 feet of what I calculated using my takeoff performance computer that, per the instructions, I calibrated to my actual takeoff performance/technique. +/-100 feet is plenty close for almost any GA operation.

In jets I’ve had a couple of instances where we found that the app we were using had bad data based on expected liftoff point relative to the TOFL numbers.

The most difficult part, and what most people ignore, is actually paying attention to the amount of runway you use.
 
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MauleSkinner said:
As a point of reference, no one on a Flight Review who has ever told me “I always have at least 50% more runway than the book” has ever been able to takeoff or land within 150% of the book distance.
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:o :hairraise:
MauleSkinner said:
In CAR3/Part 23 airplanes, examples include King Air 90s where my takeoff distance was normally within 200 feet of the published 50 foot distance, and in my Maule it was within 100 feet of what I calculated using my takeoff performance computer that, per the instructions, I calibrated to my actual takeoff performance/technique. +/-100 feet is plenty close for almost any GA operation.

In jets I’ve had a couple of instances where we found that the app we were using had bad data based on expected liftoff point relative to the TOFL numbers.

The most difficult part, and what most people ignore, is actually paying attention to the amount of runway you use.
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Since I was looking at FlySto earlier today, now I'm thinking I should start calculating an expected number and then comparing it with actual performance later.
 
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