why is L stick called throttle

[engravosaurus]

Gets in car, oops, L stick is on the right side of the floor.

As I mentioned in Post #33, after perusing the Quora discussion, all is now clear. Thrust, throttle, yaw, pitch, roll, got it all.

I guess save two things.
1) If Fly Dawg's car is analogous, does the accelerator in the car make it go up? Actually leave the road, climb?
and
2) Since the original query has been answered and all things are clear to the OP, why does this thread continue? What is drawing the continuing comments? I can think of two possibilities.

 

[Jthomp]

The true answer to the question "Does moving the L stick forward while flying with the R stick pushed forward increase lift or does it increase speed?" is - YES. It does both simultaneously, although one will likely be be more pronounced than the other.

It is the angle (relative to the horizon) of the resultant thrust vector of the propeller units which contributes to an increase in horizontal speed - if that angle is straight up and down there will be no increase in horizontal speed if there is an increase in power because the propellers are pushing the craft straight up (lift component of the thrust vector is 90 degrees, horizontal component is 0 degrees)

If the aircraft is tilted forward, say 5 degrees from straight up and down - and is moving forward at speed "x" - then the thrust vector will be tilted forward instead of being straight up and down ("lift" is being directed upward at 85 degrees relative to the horizon, "thrust" is being directed sideways [forward, actually] at a 5 degree angle.). By advancing the L stick forward the propellers are ALL sped up at the same rate simultaneously, which increases the "lift" component of the resultant thrust vector - but does not change the angle of that vector. It does, however, also increase the horizontal component of the thrust vector, therefore it increases the speed of the aircraft.

 

[engravosaurus]

The true answer to the question "Does moving the L stick forward while flying with the R stick pushed forward increase lift or does it increase speed?" is - YES. It does both simultaneously, although one will likely be be more pronounced than the other.

It is the angle (relative to the horizon) of the resultant thrust vector of the propeller units which contributes to an increase in horizontal speed - if that angle is straight up and down there will be no increase in horizontal speed if there is an increase in power because the propellers are pushing the craft straight up (lift component of the thrust vector is 90 degrees, horizontal component is 0 degrees)

If the aircraft is tilted forward, say 5 degrees from straight up and down - and is moving forward at speed "x" - then the thrust vector will be tilted forward instead of being straight up and down ("lift" is being directed upward at 85 degrees relative to the horizon, "thrust" is being directed sideways [forward, actually] at a 5 degree angle.). By advancing the L stick forward the propellers are ALL sped up at the same rate simultaneously, which increases the "lift" component of the resultant thrust vector - but does not change the angle of that vector. It does, however, also increase the horizontal component of the thrust vector, therefore it increases the speed of the aircraft.

Wow, very thorough answer, nicely written. Very clear. Actually answers the question in clear detail, unlike "Please RTM" from Fly Dawg and "You realize there is a simulator...right?" from Zzzoom3.

 

[Ing Zimmerman]

thank you

so flying forward at speed x in Mode 2
then move L stick forward
do I
1) go forward faster or
2) do I climb
3) or both?

I suggest you try it.
Put both stick forward, then move them backward and forward.
Then check your speed and altitude and let us know.

Ing.

 

[Jthomp]

I suggest you try it.
Put both stick forward, then move them backward and forward.
Then check your speed and altitude and let us know.

Ing.

Just make sure you have plenty of altitude before you do what Ing suggests: If you pull both the L and the R sticks back your bird is going to slow its forward speed down and then it will drop like a rock.

 

[With The Birds]

The true answer to the question "Does moving the L stick forward while flying with the R stick pushed forward increase lift or does it increase speed?" is - YES. It does both simultaneously, although one will likely be be more pronounced than the other.

It is the angle (relative to the horizon) of the resultant thrust vector of the propeller units which contributes to an increase in horizontal speed - if that angle is straight up and down there will be no increase in horizontal speed if there is an increase in power because the propellers are pushing the craft straight up (lift component of the thrust vector is 90 degrees, horizontal component is 0 degrees)

If the aircraft is tilted forward, say 5 degrees from straight up and down - and is moving forward at speed "x" - then the thrust vector will be tilted forward instead of being straight up and down ("lift" is being directed upward at 85 degrees relative to the horizon, "thrust" is being directed sideways [forward, actually] at a 5 degree angle.). By advancing the L stick forward the propellers are ALL sped up at the same rate simultaneously, which increases the "lift" component of the resultant thrust vector - but does not change the angle of that vector. It does, however, also increase the horizontal component of the thrust vector, therefore it increases the speed of the aircraft.

This all sounds very good untill you factor in the operation of the flight controller algorithms. Your explanation does not apply to the phantom AC's.

If you are flying at say 12m/s in any direction (based on right stick input (mode 2) and begin to increase altitude (left stick forward) the AC will climb but lateral velocity will not change. This is simply because the flight controller constantly controls the RPM if the rotors to achieve the commanded inputs within the limits set (max climb rate and horizontal speed).

Your explanation does apply to an RC Heli that simply mixes the stick inputs to control the cyclic servos on the awash plate however it is due to an influence you haven't mentioned- transitional lift. When you transition from hover to forward flight (or any direction) you actually reduce throttle to maintain altitude as the movement increases the air velocity seen by the main rotor blades increasing lift.

 

[engravosaurus]

Ok
Now we are serious and deep, but quite interesting thank you

Question: if flying at X mph and push L stick forward (Mode2) does forward speed increase?
One person who writes well says yes.
Another who also writes well says no.

Me? Dunno so I set out to do the experiment suggested above.
Was going to fly at 10mph, then push L stick forward and observe mph.

However I found maintaining Xmph is not easy; seemed to be range of ± 5 mph. I do fly over Saratoga Passage in WA State and there is usually a fair wind over the water.

So decided to try the Simulator and leave wind at 0mph. But same thing, Speed too variable to do the experiment.

Could be the problem is the stick; tis hard to hold it with absolutely no wiggle.

So someone more clever or with different (more sophisticated?) equipment will have to do the experiment. Unless…

Somewhere sometime has already been done by someone.

 

[Jthomp]

This all sounds very good untill you factor in the operation of the flight controller algorithms. Your explanation does not apply to the phantom AC's.

If you are flying at say 12m/s in any direction (based on right stick input (mode 2) and begin to increase altitude (left stick forward) the AC will climb but lateral velocity will not change. This is simply because the flight controller constantly controls the RPM if the rotors to achieve the commanded inputs within the limits set (max climb rate and horizontal speed).

Your explanation does apply to an RC Heli that simply mixes the stick inputs to control the cyclic servos on the awash plate however it is due to an influence you haven't mentioned- transitional lift. When you transition from hover to forward flight (or any direction) you actually reduce throttle to maintain altitude as the movement increases the air velocity seen by the main rotor blades increasing lift.

Thank you. Your analysis of the situation is commendable, and you are correct in saying that the on-board computer (the Flight Controller) will do what it has to do in order to stay below the maximum altitude gain rate and the maximum horizontal speed criteria. If either of those performance envelope criteria are coming close to being violated the Flight Controller will take appropriate actions to see that they are not exceeded.

My explanation is valid for the condition where the aircraft is not approaching maximum altitude gain rate nor is it approaching maximum horizontal speed. In other words, for the type of flying most of us do most of the time.

 

[With The Birds]

Thank you. Your analysis of the situation is commendable, and you are correct in saying that the on-board computer (the Flight Controller) will do what it has to do in order to stay below the maximum altitude gain rate and the maximum horizontal speed criteria. If either of those performance envelope criteria are coming close to being violated the Flight Controller will take appropriate actions to see that they are not exceeded.

My explanation is valid for the condition where the aircraft is not approaching maximum altitude gain rate nor is it approaching maximum horizontal speed. In other words, for the type of flying most of us do most of the time.

I strongly suspect your explanation to be invalid. If the flight controller is capable of keeping horizontal and vertical max velocities within preset maximum constraints (as clearly it is) why might you believe it couldn't perform similarly within the max allowable limits, i.e to maintain operator commanded rate of ascent or horizontal speed constant while varying throttle or aileron/elevator independently? The answer of course is that it can and does do this.

 

[Ing Zimmerman]

Me? Dunno so I set out to do the experiment suggested above.
Was going to fly at 10mph, then push L stick forward and observe mph.

However I found maintaining Xmph is not easy; seemed to be range of ± 5 mph. I do fly over Saratoga Passage in WA State and there is usually a fair wind over the water.

It is very difficult to maintain either speed or rate of climb. One way to do it is to program it.
Using Ltichi you can. Here is a link to a mission I have done. At the very start of the video the drone is at waypoint 1 and it travels
to waypoint 2 at a steady speed of 4 mph it is at an altitude of 23 feet at waypoint 1 and will reach waypoint 2 at an altitude of 48 feet. During that ascent the speed is constant. But of course it is programmed to be.
All this happens in the first 20 seconds.
Hoping this will help confuse everything up.

And here is the LINK.

 

[engravosaurus]

Ok
so speed forward up or speed forward not up
gonna need a serious umpire now to call balls and strikes as appears we have two "pro's" who do not agree and the "simple" test failed
I found a couple of potential umpires on the web but neither answered the query so...

 

[Jthomp]

I strongly suspect your explanation to be invalid. If the flight controller is capable of keeping horizontal and vertical max velocities within preset maximum constraints (as clearly it is) why might you believe it couldn't perform similarly within the max allowable limits, i.e to maintain operator commanded rate of ascent or horizontal speed constant while varying throttle or aileron/elevator independently? The answer of course is that it can and does do this.

You may be right.... or wrong

Suggested method of proof:
1. Indoor flight (to eliminate variable atmospheric wind speed/direction during the test)
2. Disable all forms of automatic altitude control (GPS, barometer, etc.) (to eliminate automatic Flight Controller compensation for any altitude changes during the test.)
3. Hover the quad at "referee's" eye level, with the background of his/her field of view having a long horizontal feature to assist in determining altitude gain/loss.
4. Using only the R control stick, and having the aircraft move left-to-right in front of the "referee", cause the aircraft to go from a stand-still hover to forward flight.
5. Observe the altitude change (if any occurs).
6. If the aircraft gains altitude - you win
7. If the aircraft loses altitude - someone else wins.
8. If the aircraft does not gain or lose altitude - ....... uh, what was it we were in disagreement about?

 

[With The Birds]

You may be right.... or wrong

Suggested method of proof:
1. Indoor flight (to eliminate variable atmospheric wind speed/direction during the test)
2. Disable all forms of automatic altitude control (GPS, barometer, etc.) (to eliminate automatic Flight Controller compensation for any altitude changes during the test.)
3. Hover the quad at "referee's" eye level, with the background of his/her field of view having a long horizontal feature to assist in determining altitude gain/loss.
4. Using only the R control stick, and having the aircraft move left-to-right in front of the "referee", cause the aircraft to go from a stand-still hover to forward flight.
5. Observe the altitude change (if any occurs).
6. If the aircraft gains altitude - you win
7. If the aircraft loses altitude - someone else wins.
8. If the aircraft does not gain or lose altitude - ....... uh, what was it we were in disagreement about?

The test you are proposing would prove difficult. The barometer cant be disabled easily, there is no setting for it. You might block the air admission port i suppose.

I didn't realise this was a competition.

My point has always been that the flight electronics and software constantly measure pitch velocity altitude etc and command the thrust delivered by the props independently to acheive the desired flight performance. That is why anyone can fly a phantom with very little skill or training. It will not gain altitude with increasing velocity or fly faster if you start climbing, it will do whatever you command with the joysticks (withiin operating limits).

If we were talking about an RC Heli with just a tail gyro to control yaw it would be a different conversation. I'm not sure it would be any discussion if we were to consider a quad absent IMU and flight controller, I suspect it would be impossible to control.



I

 

[engravosaurus]

Good morning

Is true some readers will say “Who cares? Just go fly, have fun.” And there is some validity in that. But it is also valid just to wish to understand how things work.

The first experiment failed from a starting point of constant motion as that is tough to achieve. But the idea of starting from hover was intriguing since hover is “easy” to achieve. And if the two vectors are connected, they should be connected at hover just as with constant motion seems to me.

And in medial research there is an old saying “to be a difference it has to make a difference”, i.e. what happens in a serious laboratory environment may not translate into a clinical difference.

So I changed the question from

If I push the L stick forward do I
1) climb
2) move forward faster or
3) both

to
If I hover and then
1) push L stick forward; what is HS on the P4P+ screen? and
2) push R stick forward; what is VS on the P4P+ screen?

And repeated the maneuvers several times.

With movement 1, HS on the screen does not change significantly from zero
With movement 2, VS on the screen does not change significantly from zero

So from a “clinical” point of view, in this test, it appears that the dji algorithm separates the two vectors and one can achieve HS without VS and VS without HS.

Which some might say has been known all along but is now known by me as well. Thank you.

 

[With The Birds]

Good morning

Is true some readers will say “Who cares? Just go fly, have fun.” And there is some validity in that. But it is also valid just to wish to understand how things work.

The first experiment failed from a starting point of constant motion as that is tough to achieve. But the idea of starting from hover was intriguing since hover is “easy” to achieve. And if the two vectors are connected, they should be connected at hover just as with constant motion seems to me.

And in medial research there is an old saying “to be a difference it has to make a difference”, i.e. what happens in a serious laboratory environment may not translate into a clinical difference.

So I changed the question from

If I push the L stick forward do I
1) climb
2) move forward faster or
3) both

to
If I hover and then
1) push L stick forward; what is HS on the P4P+ screen? and
2) push R stick forward; what is VS on the P4P+ screen?

And repeated the maneuvers several times.

With movement 1, HS on the screen does not change significantly from zero
With movement 2, VS on the screen does not change significantly from zero

So from a “clinical” point of view, in this test, it appears that the dji algorithm separates the two vectors and one can achieve HS without VS and VS without HS.

Which some might say has been known all along but is now known by me as well. Thank you.

You may have observed a slight change in altitude when the AC transitioned to horizontal flight from hover, that wouldn't be a surprise. I had initial issues when I fist started flying phantoms. Having flown RC heli's for years I had to consciously resist the urge to come back on the left stick when I started flying forwards (or in any direction) and to increase left stick when slowing to a hover. If I pay attention now I realise that I am still banking my turns also. The fact is the flight controller in the phantom does it all for us, it all comes down to transitional lift which I suspect Jthomp was basing his assumptions on.

 

[N017RW]

I have similar past experience with planks and CP-helis.

Another dynamic with horizontal flight is the downward pressure created by the shell of Phantoms and others with similar designs.

 

[engravosaurus]

Cool.

I now understand (more or less of course)
1) the several meanings of the term “throttle” and
2) the history of the term “throttle” and
3) that the Flight Controller mixes and matches the various stick commands by adjusting rpm's here and / or there to change this vector and / or that

Thank you

 

[engravosaurus]

Have a friend who is a retired 747 pilot; had a coffee and a long chat about throttle / thrust / altitude / speed. Also have now perused countless web pages on said topic.

Was clear that after years of flying, the pilot does not use the terms anymore. Actions have become completely automatic, terms are no longer needed. For him is like walking, just happens.

Terms only come into play when explaining things to beginners. Which is why they should be as accurate and consistent as possible, which is not the case in the P4P+ manual.

Also, as some said above, the term throttle is mostly gone in their world in favor of thrust lever.

Also, all other things being equal, more thrust and the plane will climb. However, gaining altitude is virtually never done by adjusting only thrust, many other adjustments are also made.

Is truly fascinating.

The best instruction I found to gain altitude is

Man, just push the black thingy in some, and pull the wheel thingy back some, and don't let the horn thingy come on.....

So I looked on my P4P+ and in the manual for the “black thingy”, the “wheel thingy” and the “horn thingy” and could not find them. (tee hee)

As an aside, have continued to fly but still movements are not automatic; but they are more automatic than they were at the outset. No longer think “which stick” but still sometimes push yaw and roll the wrong way, especially when P4P+ is far out and visible only as a dot.

 

[AlanTheBeast]

newbie query

If you move the sticks further and further from center, the speed of the activity increases.

So why is the L stick referred to as the throttle? (in Mode 2)

It's just bad nomenclature.

It's the "up/down" stick.

The right stick is not "aileron" or "elevator" either. It's the go forth/back/left/right stick.

The only one correctly named is the yaw stick.

 

[N017RW]

The right stick is not "aileron" or "elevator" either. It's the go forth/back/left/right stick.
.

i.e. Pitch and Roll