Pulling it too soon....

[docmirror]

During winter I usually fly alone, and on cool days with modest weight I've been used to rotating at the bottom of the white arc. As soon as I establish decent rate of climb, the gear comes up.

for the past two weeks, I've had several people in the plane with me so nearer gross, and the temps have been somewhat higher than March. So, when I wasn't paying attention I'd pull it off about the bottom of the white arc and wasn't at all happy with the climb rate.

Had to sit on the ramp at an airport for a few minutes so I gave it a bit of cogitation. Even after flying for 20 years, things you forget and/or don't connect.

I've been putting the plane into an area of reverse-command vis-a-vis the deck angle and speed. No surprise really that the climb was sluggish even in ground effect. The next take off, I waited until I was passing 70MPH on the ASI and not only did it hop off nicely, but the climb rate was back to my usual fantastic, even with the load on.


Nothing wrong with the equipment, just a bad nut behind the yoke....DOH!

 

[jesse]

I think the term 'rotate for takeoff' is over used in primary flight training for small planes. People get so fixated on a specific airspeed instead of the feel. As we all know the airspeed will be different for every takeoff while the feel remains constant. It us unlikely that a pilot is going to properly calculate the rotation speed for every flight in a Cessna 172. So instead he takes off each time at a different AoA with different levels of energy.

My technique once I get comfortable in a plane is to figure out the trim setting that works well and allows the airplane to fly off with slight back-pressure. The plane will then takeoff when its ready which of course changes with temperature and weight.

 

[docmirror]

Good plan, and prolly works in every plane... except the V tail Bonanza. The trim has a takeoff range and you really don't want to try taking off outside that range. It's a quirk of this plane that it's not gonna come off the runway with trim unless the trim wheel is almost all the way down. Then when it comes off, the deck angle will be way too high. But it sounds good in a 172!

 

[jesse]

Good plan, and prolly works in every plane... except the V tail Bonanza.

I've never flown in a V-tail Bonanza (hint hint spike). My Bonanza flying is limited to Chip's A36 at Gastons last year. Nice airplane, fast, easy to fly.

 

[sba55]

Good plan, and prolly works in every plane... except the V tail Bonanza. The trim has a takeoff range and you really don't want to try taking off outside that range. It's a quirk of this plane that it's not gonna come off the runway with trim unless the trim wheel is almost all the way down. Then when it comes off, the deck angle will be way too high. But it sounds good in a 172!

I find that the green trim range is pretty useless for takeoff.

First, I agree with Jesse that a) rotation is an overused concept and b) you don't really rotate in a 172 or similar. Some HP and heavier planes are different, though, and Bonanzas definitely need more back pressure to come off the runway.

Personally, I ignore the trim range, and usually set it to about 5-6 (IIRC, the trim range ends at 3?). With 2 people up front, that means that it will still take a little bit of back pressure, but it's nothing compared to what you'd have to use if you set it to somewhere in the trim range. Also, I used to "rotate" at about 85 knots before I changed my takeoff trim approach. Now, it'll easily get off the runway at about 75. I'll need to push on the yoke quite a bit to stay in ground effect once the wheels come up, but that's about it. This also sets me up for a nice 130 IAS climb.

-Felix

 

[docmirror]

Felix, I'm guessing you have a later model Bo with the big(normal) tail. I have a B35 which is the small tail. I've tried taking off with the trim wheel to far up and it's not happy. IF I follow the checklist, and don't pull to soon, all is copacetic.

 

[dmccormack]

Good plan, and prolly works in every plane... except the V tail Bonanza. The trim has a takeoff range and you really don't want to try taking off outside that range. It's a quirk of this plane that it's not gonna come off the runway with trim unless the trim wheel is almost all the way down. Then when it comes off, the deck angle will be way too high. But it sounds good in a 172!

Hmmmm.... I'm not sure about that....

The 35 and 36 Series both sit with about 5-7 degree nose up attitude on the ground. (To check this set up the Attitude Indicator in level flight then look at it once you're finished taxiing). A good exercise is to have a knowledgeable pilot stand outside and watch as you pull the yoke back and let him tell you when the elevator position is neutral.

Most new (and some old!) Bonanza pilots are surprised how much back pressure is required to achieve neutral.

If you place the trim indication within the specified range (the 36 POH adds the number to use -- 3 if fwd, 6 if normal loaded) and hold the elevator in the neutral position, the airplane will fly itself off the ground. If you don't hold ANY back pressure, the elevator is in the down position due to down spring pressure. This will retard to liftoff point.

As far as teaching "rotation," my experience so far has been that students wait for something to happen. The airplane is ready to fly far sooner than they expect.

I haven't encountered someone yet who yanked it off the ground. The more likely error is not holding the yoke in a neutral position. This is the case in Bonanzas (with rather heavy down force) and Cessna's (with far less down force).

The real value in teaching rotation is to get the student to understand the sooner the wings can bear some weight, the better. Friction is reduced, aerodynamic forces become more effective, and speed increases. If the POH specifies Vr, then the airplane was found to be ready to fly at that speed at the specified weight, in standard conditions.

Clearly there's some feel required for conditions outside the certification regime, but I'll be willing to bet that the more usual error is letting the airplane roll 20-30% farther than needed when the airplane would be better off flying.

 

[sba55]

Felix, I'm guessing you have a later model Bo with the big(normal) tail. I have a B35 which is the small tail. I've tried taking off with the trim wheel to far up and it's not happy. IF I follow the checklist, and don't pull to soon, all is copacetic.

That's interesting. I fly a -35 (V35), too, and that hasn't been my experience. Tire pressure can make quite the difference, too. I used to maintain 40 in the mains, 40 up front. According to some, however, the wings will barely produce lift on take off in that case. I switched to 32 in the mains, and the plane now gets off the runway much more naturally. My plan usually is somewhere around 6 on the trim with two people up front, and around 4 with folks in the back. At about 65 knots, the nose usually becomes light, and take off is about 70-75 knots.

Edit: I get it now. You're talking about a "B" model 35. In that case, I really have no useful input to contribute I thought by "normal" tail, you meant the straight tails.

-Felix

 

[docmirror]

Hmmmm.... I'm not sure about that....

The 35 and 36 Series both sit with about 5-7 degree nose up attitude on the ground. (To check this set up the Attitude Indicator in level flight then look at it once you're finished taxiing). A good exercise is to have a knowledgeable pilot stand outside and watch as you pull the yoke back and let him tell you when the elevator position is neutral.

Most new (and some old!) Bonanza pilots are surprised how much back pressure is required to achieve neutral.

If you place the trim indication within the specified range (the 36 POH adds the number to use -- 3 if fwd, 6 if normal loaded) and hold the elevator in the neutral position, the airplane will fly itself off the ground.

Nope, go find a pre SN-2673 Bo with the small tail. It won't fly off unless I have the trim well fwd with a full pax load. Small tail, as mentioned. That's one of the things Beech 'fixed' when they increased the ruddervator surface, changed the V angle and changed the deflection of the elevons.

I've never tried to let it fly off without back pressure, but I've had the trim out of the TO zone, and it didn't want to move after quite a bit of speed.

One other thing to note is that I keep my plane with a significant nose high attitude by over-inflating the nose strut and leaving the mains normal for prop clearance.

 

[dmccormack]

Nope, go find a pre SN-2673 Bo with the small tail. It won't fly off unless I have the trim well fwd with a full pax load. Small tail, as mentioned. That's one of the things Beech 'fixed' when they increased the ruddervator surface, changed the V angle and changed the deflection of the elevons.

I've never tried to let it fly off without back pressure, but I've had the trim out of the TO zone, and it didn't want to move after quite a bit of speed.

One other thing to note is that I keep my plane with a significant nose high attitude by over-inflating the nose strut and leaving the mains normal for prop clearance.

You don't get much earlier than S/N 90 (1947), and trim in the green works.

This model also has the Continental E-185-1, and the electric (Beech) prop governor with the 2 blade Hartzell upgrade (Aluminum).

 

[dmccormack]

I've never tried to let it fly off without back pressure, but I've had the trim out of the TO zone, and it didn't want to move after quite a bit of speed.

Exactly -- you must apply back pressure to achieve a neutral ruddervator position -- you're fighting against some weight and down springs.

 

[Teller1900]

Good plan, and prolly works in every plane... except the V tail Bonanza. The trim has a takeoff range and you really don't want to try taking off outside that range. It's a quirk of this plane that it's not gonna come off the runway with trim unless the trim wheel is almost all the way down. Then when it comes off, the deck angle will be way too high. But it sounds good in a 172!

Must be a Beech thing, the 1900 is the same way. Our SeeGee wheel gives us our t/o trim setting, though we usually use 3 units ANU for everything but unusual weight distributions. With the trim set like that it takes a good bit of a tug to get the plane off the runway at Vr, but requires immediate nose down trim to keep the nose from launching past 20 degrees up. If you have the trim set for where it will be in the climb, you won't get it off the deck until you've exceeded the gear speed, and if you leave it at t/o through the climb, you're gonna get a pretty good work out (especially once the gear comes up).

When I started in the Seminole, they taught us to "rotate" at 75kts; it works, but it takes a pretty good pull initially. After about 70 or 80 hrs of doing that, I ended up talking with one of the owners of the school who told me he thought "that's a stupid idea. Wait until at or near blue line [88] and the plane will jump off the deck much easier and it'll give you a much better margin of safety if something goes wrong." And so I started pulling a lot later, and sure enough...it was a lot easier.

 

[dmccormack]

Must be a Beech thing, the 1900 is the same way. Our SeeGee wheel gives us our t/o trim setting, though we usually use 3 units ANU for everything but unusual weight distributions. With the trim set like that it takes a good bit of a tug to get the plane off the runway at Vr, but requires immediate nose down trim to keep the nose from launching past 20 degrees up. If you have the trim set for where it will be in the climb, you won't get it off the deck until you've exceeded the gear speed, and if you leave it at t/o through the climb, you're gonna get a pretty good work out (especially once the gear comes up).

Does the 1900 Elevator employ down springs?

 

[docmirror]

Exactly -- you must apply back pressure to achieve a neutral ruddervator position -- you're fighting against some weight and down springs.

Yah, said that in post 3 and 9. SN 90 is pretty old all right. I have an E-224 so 22% more HP. With the trim in the TO zone, it'll go fast down the runway, but I've never tried to wait until it goes off by itself. By the time I'm at 80MPH, I've already lifted.

It's not a problem with the plane, or the trim or anything else, it was simply pulling too soon and presenting too much drag at a slow speed. It's fixed now, I was just mentioning it in case someone else runs into the same situation.

 

[Teller1900]

Does the 1900 Elevator employ down springs?

I honestly don't know. Our book doesn't say anything about down springs, so I'd bet not. The elevator is pretty heavy on its own.

 

[dmccormack]

According to this NTSB report, the Beech 1900 series has elevator down springs.

"The Model 1900D involved in the accident was equipped with a mechanically operated
pitch control system, (Reference Figure 1 and Attachment 2). The horizontal tail surfaces are mounted at the top of the vertical stabilizer. Each side of the horizontal tail has an elevator and the inboard trailing edge of each elevator has a cut-out for a single partial-span trim tab.
The forward outboard corner of each elevator has a balance weight that is rounded and is located behind the horizontal stabilizer when the elevator is near neutral.
The elevators are each connected by separate rods to a single aft elevator bellcrank. The aft elevator bellcrank is located within the junction of the vertical and horizontal stabilizers and has two springs connected to the aircraft structure. The spring tension is toward the nose-down direction." (emphasis mine)

This may explain the need for back pressure on takeoff -- consistent with other Beech airplanes.

 

[dmccormack]

Yah, said that in post 3 and 9. SN 90 is pretty old all right. I have an E-224 so 22% more HP. With the trim in the TO zone, it'll go fast down the runway, but I've never tried to wait until it goes off by itself. By the time I'm at 80MPH, I've already lifted.

It's not a problem with the plane, or the trim or anything else, it was simply pulling too soon and presenting too much drag at a slow speed. It's fixed now, I was just mentioning it in case someone else runs into the same situation.

Sorry, Doc, but if there is a Vr published in a POH for an airplane, that's the number to target to set an angle of attack in the best position to lift off.

For the Straight 35, that number is 73 MPH at gross weight (which weight I've never flown in this airplane). I'm not usually looking at the ASI for Vr, but the nose is up and the airplane is light on it's feet at 70 -- by 75 we're flying, and the reduced friction allows the airplane to accelerate to Vx rapidly.

This is also why short field takeoff procedures in nearly every airplane stress getting the nose up -- you get the wings working sooner, thereby reducing the forces slowing the airplane down and keeping it from flying.

I'm not sure what you mean by "presenting too much drag at a slow speed"?

 

[Teller1900]

According to this NTSB report, the Beech 1900 series has elevator down springs.

snip

This may explain the need for back pressure on takeoff -- consistent with other Beech airplanes.

Interesting! Here's all our book says:

Ailerons and Elevator: The ailerons and elevator are controlled by the pilot's and copilot's yoke. The yokes are interconnected by a T-bar and chain assembly located behind the instrument panel. The ailerons are moved by cables routed through pulleys and bell cranks to adjustable push-pull rods attached to the ailerons. The elevator is also moved by cables routed through pulleys and bell cranks, but is connected by a torque tube.

I don't know what the torque tube is, but that's the rather simplistic explanation our book has.

 

[docmirror]

Sorry, Doc, but if there is a Vr published in a POH for an airplane, that's the number to target to set an angle of attack in the best position to lift off.

For the Straight 35, that number is 73 MPH at gross weight (which weight I've never flown in this airplane). I'm not usually looking at the ASI for Vr, but the nose is up and the airplane is light on it's feet at 70 -- by 75 we're flying, and the reduced friction allows the airplane to accelerate to Vx rapidly.

This is also why short field takeoff procedures in nearly every airplane stress getting the nose up -- you get the wings working sooner, thereby reducing the forces slowing the airplane down and keeping it from flying.

I'm not sure what you mean by "presenting too much drag at a slow speed"?

Same number in my book. As mentioned, way back in post 1, I usually fly solo in the winter. So, I can get airborne pretty fast, and at pretty low speed. Say, around 60-ish MPH.

Now, when I rotate on a hotter day, with a much higher load at 60-ish, the plane will mush forward as expected. Just poor judgment on my part.

Now being a CFI, you must be familiar with the area of reverse command, or 'back side of the power curve'. When I lift off early at heavier weight I get near or in the reverse command situation where there is a very high AOA, or said another way, 'presenting too much drag'.

 

[dmccormack]

Now being a CFI, you must be familiar with the area of reverse command, or 'back side of the power curve'. When I lift off early at heavier weight I get near or in the reverse command situation where there is a very high AOA, or said another way, 'presenting too much drag'.

The Angle of attack will be the same within normal weight range -- only the speed will change.

If you use the same angle of attack at a heavier weight and same speed, the airplane will not climb as well -- more speed (airflow) is required to generate the added lift to carry the added weight.

You could simply increase the angle of attack to compensate for the increased weight, but then you might creep into the high induced drag, high power regime known as "backside of the power curve" or "Region of reversed command" (Though this is unlikely on takeoff, since ground effect is minimizing total drag, and the AoA would have to be fairly extreme while in ground effect).

Thus once you find the best initial and subsequent climb angle for your airplane -- use it, every time. The speed will automatically adjust for the weight.

In just about every Bonanza, 10 degrees nose up works.

As far as the "need to apply back pressure even though the trim is set" -- keep in mind that the trim is set to a speed, and the green bar (takeoff trim) is trim speed of Vy -- which is considerably faster than Vr and Vx.

Model 35 speeds:

• Takeoff Rotation -- Vr 73 MPH
• 50 Foot 79 MPH
• Max Rate of Climb -- Vy 100 MPH
• Max Angle of climb -- Vx 78 MPH
• Cruise Climb 120 MPH

To go from the trim speed of Vy to Vx, you need to pull back. The trim setting is set where it is so that if you suddenly let go of the yoke, the nose would go down (after a few oscillations the airplane would stabilize at trim speed, power on or off).


(Correction -- I gave the wrong numbers before -- the earlier Bonanzas sit nose up 4.5- 5 degrees, the later (A36) models at 3.5-4 degrees.)

 

[flyingcheesehead]

Thus once you find the best initial and subsequent climb angle for your airplane -- use it, every time. The speed will automatically adjust for the weight.

Hmmm. Are you sure? What about a high-DA situation... If you use the same climb angle, your airspeed will be lower. Thinking that you need the right climb angle instead of the right speed will get you killed taking off from some of the fields out west. (ie rockies - I guess that's out east for the west-coast folks. )

If you mean angle of attack and not deck angle, well, do you have an AoA indicator? Most light planes don't.

 

[dmccormack]

Hmmm. Are you sure? What about a high-DA situation... If you use the same climb angle, your airspeed will be lower. Thinking that you need the right climb angle instead of the right speed will get you killed taking off from some of the fields out west. (ie rockies - I guess that's out east for the west-coast folks. )

If you mean angle of attack and not deck angle, well, do you have an AoA indicator? Most light planes don't.

The Attitude Indicator is as close as most light planes have to an AoA indicator.

In a high DA situation, you need to be faster to achieve the same lift at any AoA -- whether the DA is due to high temps/humidity or actual elevation. Couple the requirement for faster TAS with actual faster GS and that long runway gets mighty short in a hurry.

The optimal AoA to achieve Vx and Vy will change as the airplane reaches its service ceiling, and the actual values for both will change (usually down).

So while you are right that one angle won't work in every situation, it's more correct to say there is an optimal angle in given conditions that will achieve Vx and Vy.

Pilots should know what the optimal angle is for the a/c they fly and adjust accordingly based on performance tables. This provides another cue as to when things just aren't going right, and flying is all about recognizing the available cues.

 

[flyingcheesehead]

While most of what you say is technically correct, IMHO the way you say it could lead to confusion. Since I pestered another new CFI on the board about this sort of thing, I'm gonna pester ya. No hard feelings, but... While I am not a CFI, I do teach folks how to operate another complex and potentially dangerous piece of equipment, and... Ya really gotta watch what you say. Law of primacy still applies even when they misunderstand you!

The Attitude Indicator is as close as most light planes have to an AoA indicator.

Hmm... Not really. In fact, not at all. Go do a 60 degree steep turn with the nose on the horizon. AoA is way higher, pitch attitude is unchanged. Go to a very high-DA situation, and likewise, the AoA will be much different compared to the attitude indicator. If you teach this to a student at sea level and they go for a trip to the mountains, they are in danger. IMO, the airspeed indicator is as close as most light planes have to an AoA indicator, but again it only works that way for a given load factor.

In a high DA situation, you need to be faster to achieve the same lift at any AoA --

Faster *true* airspeed - Same *indicated* airspeed. That's why airspeed is a better measure than pitch attitude. Yes, set an initial pitch attitude on takeoff (and realize WHY you set that attitude and how you'll need to adjust for DA and other factors), but verify it with airspeed.

whether the DA is due to high temps/humidity or actual elevation. Couple the requirement for faster TAS with actual faster GS and that long runway gets mighty short in a hurry.

Bingo.

The optimal AoA to achieve Vx and Vy will change as the airplane reaches its service ceiling, and the actual values for both will change (usually down).

Doesn't Vx go up? IIRC, Vx goes up and Vy goes down and they are equal at the plane's absolute ceiling (where both climb rate and angle would be 0).

So while you are right that one angle won't work in every situation, it's more correct to say there is an optimal angle in given conditions that will achieve Vx and Vy.

Right. I emphasized "given conditions" because it won't always be the same, and a student or even a certified pilot may not realize what factors change that angle, and how much, so make sure they know that they must verify that angle with indicated airspeed.

Pilots should know what the optimal angle is for the a/c they fly and adjust accordingly based on performance tables. This provides another cue as to when things just aren't going right, and flying is all about recognizing the available cues.

Right on. The easiest cue is right there to the left of the attitude indicator. And that's gonna be the one that still works when your student has 500 hours and is off flying a Cirrus and didn't even think about looking at the performance charts 'cuz that stuff is just for student pilots.

 

[jesse]

The Attitude Indicator is as close as most light planes have to an AoA indicator.

IMHO, the attitude indicator is far from an AoA indicator and teaching that they are is a very dangerous game to play. The more dangerous the conditions the more they will differ. If a pilot attempts to achieve a certain climb angle without thought on a hot day in a heavy airplane he is likely to produce a **** load of drag and never get high enough to survive.

The pressure on the yoke combined with the response of the controls is how I determine angle of attack. Cover up the primary flight instruments and play at altitude and you program the AoA gauge into your head. This doesn't work for every airplane--but it has worked for everything I've flown.

This is just my opinion and my opinion is worth a lot less than others on this forum.

 

[dmccormack]

While most of what you say is technically correct, IMHO the way you say it could lead to confusion. Since I pestered another new CFI on the board about this sort of thing, I'm gonna pester ya.

Any CFI who "knows it all" needs to be avoided at all costs.

No hard feelings, but... While I am not a CFI, I do teach folks how to operate another complex and potentially dangerous piece of equipment, and... Ya really gotta watch what you say. Law of primacy still applies even when they misunderstand you!

Don't worry -- tough skins are issue items for Infantry Officers.

And I learned to be careful what I say as well -- from nuclear weapons to M1 tanks to det cord to infantry live fire to sale presentations. Be careful little tongue what you say!

Hmm... Not really. In fact, not at all. Go do a 60 degree steep turn with the nose on the horizon. AoA is way higher, pitch attitude is unchanged. Go to a very high-DA situation, and likewise, the AoA will be much different compared to the attitude indicator. If you teach this to a student at sea level and they go for a trip to the mountains, they are in danger. IMO, the airspeed indicator is as close as most light planes have to an AoA indicator, but again it only works that way for a given load factor.

That's why I said it is "the closest thing to an AoA indicator" and the context was takeoff (I probably should have made that more clear).

If you're banking during takeoff the angles will be so slight the load factor will be negligible. If you're baking enough on takeoff that you are imposing load factor you're Sean Tucker or in a load of hurt.

Faster *true* airspeed - Same *indicated* airspeed. That's why airspeed is a better measure than pitch attitude. Yes, set an initial pitch attitude on takeoff (and realize WHY you set that attitude and how you'll need to adjust for DA and other factors), but verify it with airspeed.

Sorta.

The variation in pitch in the typical SEL normally aspirated airplane in normal operation may be as much as 2 degrees. If you read back my original response to the OP was clarifying that the sensation of "pulling it off" was probably more due to misunderstanding the downforce on the Bonanza ruddervators and the function of Vr and Vx to "trim in the green."

Doesn't Vx go up? IIRC, Vx goes up and Vy goes down and they are equal at the plane's absolute ceiling (where both climb rate and angle would be 0).

Correct. I should have said Vy goes down.

Right. I emphasized "given conditions" because it won't always be the same, and a student or even a certified pilot may not realize what factors change that angle, and how much, so make sure they know that they must verify that angle with indicated airspeed.

Absolutely. See again my comment regarding cues.

The easiest cue is right there to the left of the attitude indicator. And that's gonna be the one that still works when your student has 500 hours and is off flying a Cirrus and didn't even think about looking at the performance charts 'cuz that stuff is just for student pilots.

And she/he's an accident waiting to happen, Cirrus or Cessna.

If all this pilot knows about takeoff is achieving a certain speed, I'll bet dollars to donuts they have no clue about stalls and angle of attack.

Let me restate to clarify, since the discussion has wandered a bit:

• Bonanzas (and apparently most --if not all-- Beech airplanes) have downsprings on the elevator/ruddervator surface which increases the perceived back pressure required to maintain neutral elevator position.
• The Angle of Attack on takeoff will be constant while speed changes in relation to weight, all other conditions being equal (Heavier = faster, lighter = less speed).
• The angle of attack on takeoff is relatively constant throughout the airplane's normal operating envelope within 2-3 degrees 9though speed will vary).
• As density altitude increases, the true airspeed must increase to achieve the same measure of lift at a lower DA, given a constant AoA.
• The green band on the trim indicator in Bonanzas is calibrated to trim speed, not AoA -- and thus to achieve Vx back pressure is required until obstacles are cleared.

 

[docmirror]

The Angle of attack will be the same within normal weight range -- only the speed will change.

If you use the same angle of attack at a heavier weight and same speed, the airplane will not climb as well -- more speed (airflow) is required to generate the added lift to carry the added weight.

did you just ignore my initial post where I said that exact thing?

 

[dmccormack]

IMHO, the attitude indicator is far from an AoA indicator and teaching that they are is a very dangerous game to play. The more dangerous the conditions the more they will differ. If a pilot attempts to achieve a certain climb angle without thought on a hot day in a heavy airplane he is likely to produce a **** load of drag and never get high enough to survive.

The pressure on the yoke combined with the response of the controls is how I determine angle of attack. Cover up the primary flight instruments and play at altitude and you program the AoA gauge into your head. This doesn't work for every airplane--but it has worked for everything I've flown.

This is just my opinion and my opinion is worth a lot less than others on this forum.

We were posting at the same time, but I agree with what you.

But in the discussion context (takeoff angle of attack) it's the closest instrument to an AoA indicator in level flight.

I also agree that Mark 1 Eyeballs are superior, given that big not-so-artificial horizon out the window.

BUT -- if a Bonanza owner whats to know the ideal climb angle in his a/c, he should take off while a safety pilot records the indications on the AI (if he/she is not IR -- if he/she is, that pilot better be able to divide attention and glance at the AI and figure out the indicated climb angle).

Unless there's something different about that Bonanza, you'll find the angle is 10 degrees pitch up.

 

[dmccormack]

did you just ignore my initial post where I said that exact thing?

You did?

 

[docmirror]

You did?

I bolded it for you.

 

[dmccormack]

I've been putting the plane into an area of reverse-command vis-a-vis the deck angle and speed. No surprise really that the climb was sluggish even in ground effect. The next take off, I waited until I was passing 70MPH on the ASI and not only did it hop off nicely, but the climb rate was back to my usual fantastic, even with the load on.

You weren't putting "the plane into an area of reverse-command vis-a-vis the deck angle and speed," but rather lifting off at the same angle of attack (probably) and the same speed -the amount of lift was the same -- the problem was the weight was greater.

Honestly -- it wasn't the region of reversed command that was responsible for the poor climb performance.

Think of it this way -- If you were going faster at the same AoA, the climb gradient would have been poor as well.

It's all about combining the right AoA (which in the Bonanza is relatively constant with slight decrease as DA increases) and airspeed (given the weight -- faster is required for heavier).

 

[dmccormack]

Ya really gotta watch what you say. Law of primacy still applies even when they misunderstand you!

I don't think primacy applies here.

I doubt anyone is learning to fly by reading this board.


If they are, I hope it's far from here.

 

[flyingcheesehead]

Any CFI who "knows it all" needs to be avoided at all costs.

Agreed... But I don't see where that fits with anything I said.

That's why I said it is "the closest thing to an AoA indicator" and the context was takeoff (I probably should have made that more clear).

Well, maybe we're actually disagreeing instead of merely misunderstanding then.

If you're banking during takeoff the angles will be so slight the load factor will be negligible. If you're baking enough on takeoff that you are imposing load factor you're Sean Tucker or in a load of hurt.

True - The very high DA is a much better example in this context.

And she/he's an accident waiting to happen, Cirrus or Cessna.

Right - But most of your students are going to cut more corners after you're done with 'em than when you're still teaching them. Sad fact of life.

If all this pilot knows about takeoff is achieving a certain speed, I'll bet dollars to donuts they have no clue about stalls and angle of attack.

Probably not - But there's a scary high number of pilots who don't understand that either. But, if they understand that they need to use indicated airspeed instead of a climb angle or a perceived groundspeed, they'll at least be alive and ignorant.

 

[flyingcheesehead]

I don't think primacy applies here.

I doubt anyone is learning to fly by reading this board.


If they are, I hope it's far from here.

Learning to fly? No. Learning about flying? Heck yes. I've learned a TON about flying from people on web boards over the years, and other folks are doing the same. In fact, I hold the people here in high regard as pilots because they are here to associate with other pilots and learn more about flying. The folks who finish their ratings and DON'T learn from books, seminars, web boards, etc. are the ones who scare me.

 

[Henning]

I think the term 'rotate for takeoff' is over used in primary flight training for small planes. People get so fixated on a specific airspeed instead of the feel. As we all know the airspeed will be different for every takeoff while the feel remains constant. It us unlikely that a pilot is going to properly calculate the rotation speed for every flight in a Cessna 172. So instead he takes off each time at a different AoA with different levels of energy.

My technique once I get comfortable in a plane is to figure out the trim setting that works well and allows the airplane to fly off with slight back-pressure. The plane will then takeoff when its ready which of course changes with temperature and weight.

Most of the time, trimming for takeoff is an excellent way of doing this. When you move into twins though, you have to stop this as the plane will fly off long before a safe speed. When flying multi, rotational speed is critical.

 

[jesse]

Most of the time, trimming for takeoff is an excellent way of doing this. When you move into twins though, you have to stop this as the plane will fly off long before a safe speed. When flying multi, rotational speed is critical.

Agreed. Twins really change things.

 

[gismo]

Dan, I think you have been writing AoA when you mean deck angle or pitch attitude. The AoA in a Bonanza or any other airplane for Vy or Vx doesn't change with weight but the pitch attitude does. It is true that the IAS (CAS actually) for the same AoA including Vy when flying at a higher weight but not when the density altitude is higher at the same weight (I don't think you said that last bit, I'm just adding it for clarity).

It's all about combining the right AoA (which in the Bonanza is relatively constant with slight decrease as DA increases) and airspeed (given the weight -- faster is required for heavier).

 

[dmccormack]

Dan, I think you have been writing AoA when you mean deck angle or pitch attitude. The AoA in a Bonanza or any other airplane for Vy or Vx doesn't change with weight but the pitch attitude does. It is true that the IAS (CAS actually) for the same AoA including Vy when flying at a higher weight but not when the density altitude is higher at the same weight (I don't think you said that last bit, I'm just adding it for clarity).

Actually, I meant AoA -- "Deck angle" and "Pitch Attitude" are other ways of saying Angle of Attack (unless the wings pivot).


And you're right -- AoA does change slightly (less AoA) at higher DA/ Pressure Altitude while TAS needs to increase to achieve the same amount of lift for the same amount of weight as Standard Conditions.

 

[dmccormack]

Learning to fly? No. Learning about flying? Heck yes. I've learned a TON about flying from people on web boards over the years, and other folks are doing the same. In fact, I hold the people here in high regard as pilots because they are here to associate with other pilots and learn more about flying. The folks who finish their ratings and DON'T learn from books, seminars, web boards, etc. are the ones who scare me.

I agree 100%.

But that's not in the realm of the law of Primacy.

 

[dmccormack]

Right - But most of your students are going to cut more corners after you're done with 'em than when you're still teaching them. Sad fact of life.

Well, it's not just about me "teaching them."

I did W&B and checked DA before taking off many times. Haven't you?

Probably not - But there's a scary high number of pilots who don't understand that either. But, if they understand that they need to use indicated airspeed instead of a climb angle or a perceived groundspeed, they'll at least be alive and ignorant.

Again, the thread and discussion has wandered a bit, but I can't agree here. I think every pilot needs to understand all the cues available to him/her. If all she's got is the ASI, and is betting everything on that one cue, there will eventually be a problem.

All pilots in visual t/o conditions look out the window -- listening, feeling, and "knowing" when the airplane is getting ready to fly. As someone said earlier here, the pilot should be able to takeoff with the panel covered.

How are we doing this? We're adding back pressure, we're seeing the nose lift, we're hearing the right noises, we're seeing the ground go by, we see we haven't reached our liftoff point yet, and we are setting a pitch (AoA) we've seen 10,000 times before.

(In a zero-zero takeoff, guess which instrument is replacing the ground to verify pitch?)

Please don't misunderstand -- AoA is rather vague to most pilots and the ASI becomes their AoA indicator. BUT (a emphatic but), we aren't flying airspeed -- we are flying a wing -- and we need to know -- intuitively and otherwise -- what that wing is doing.

 

[dmccormack]

As an aside...

I appreciate all the feedback/comments.

This is another reasons why forums are useful -- we can discuss, proffer arguments, see how we need to adjust how we think/explain, and thereby become better aviators.

It's all good.


(now it's time to log some actual)