Please explain the Throttle

[ogiedogg]

Hey all... I have been simming for a long time, that aside. I would like one of the experts here explain the throttle in the KA 50 and in this sim. As often is the case R/L and other sims are always different and this is my reason for my question. Also we have become used to the common format now which is the linked Collective and Throttle. I often get the engine over rev. warning and I think this has to do with it. Thanks in advance......

[AlphaOneSix]

The engine throttles in the sim (and in the real aircraft) are the two yellow levers at the bottom of the left rear panel. They move through a range, but they have detents to stop them at certain positions. These position correspond to: IDLE (full down), some intermediate posotion whose use still mystifies me, AUTO (used for all dual-engine flight operations), and EMERGENCY (for single-engine flight operations). The throttle levers on the Ka-50 are commonly referred to (on Western aircraft) as ECLs (engine condition levers) or PCL's (power condition levers).

 

During all modes of dual-engine flight, the throttles should be placed in the AUTO position. In this position, engine power is adjusted automatically in order to keep the rotor speed at its nominal setting. If you increase the collective for example, the rotor will try to slow down, which will cause the engines to automatically produce more power in order to prevent this slowdown (called rotor droop). Nearly all modern helicopters now have some form of automatic throttle control in order to increase safety, reduce pilot workload, and increase efficiency.

 

When you say that you are geting an "engine over rev. warning", I assume that you are referring to the "power limit" warnings. This warning occurs because you are asking the engines for too much power, and the engine electronic governor system is automatically limiting further power output in order to prevent damage to the engines. Placing the throttle levers in the EMERGENCY (full up) position will provide you with more power, at the expense of engine duty life. In practice, the use of the EMERGENCY throttle setting is limited to OEI (one engine inoperative) flight. In other words, if you had an engine failure in-flight, you would increase the throttle level of the operating engine to EMERGENCY. Also, it's important to note that operating the engines at their power limit will cause the engines to fail if you stay at that power setting for too long. You can see your power setting by looking at the EPR (engine pressure ratio) gauge at the forward end of the right panel (above the battery switches). The red arrows in the middle indicate which power setting you're in, while the yellow arrows indicate the power level for each engine. For prolonged flight (more than 6 minutes) you want those yellow markers *below* the "K" marker (cruise power setting) in order to prevent eventual damage to the engine.

 

I hope this helps, but please feel free to continue asking questions if anything I wrote didn't make any sense.

[Chelco]

A-1-6, thanks for the great explanation.

 

Somebody sticky this.

[Jack McCoy]

Yes, great answer.

---

Somebody did "sticky" it, in the Flight Manual PDF document.

[nemises]

In game sence, this means you should not have the "Throttle" axis bound to an axis on your HOTAS (unless you have a spare one) ..as the proper usage of the throttle is essentially digital (ie move from Idle, up 1 step to low power, up 1 more step to auto).

 

It is very tempting for people who first get the game to bind up the Throttle axis instead of the collective.

[CAT_101st]

the throttle can not be bound to a axes only to a key bind.

[nemises]

oh really?..I thought it was a mapable Axis also

 

*edit* yep, there they are, "left throttle" , "right throttle" and "throttle" are all bindable Axis... guess thats for those with a Quadrant throttle, lol..

[slug88]

the throttle can not be bound to a axes only to a key bind.

 

Not true. The throttle can be bound to an axis. I have it bound to one of the spare rotaries on my X-52.

[HitchHikingFlatlander]

Same here I have each engine mapped to my dual AV8R throttles and set them to auto power before each flight.

[Topgun505]

Incorrect Cat. I have the throttle set to the small slider-control on my Saitek throttle unit (in order to power to idle after landing or throttle to max in case of single engine failure). As a matter of fact that seems to be about the ONLY control I can set that slider to ... but that works. :)

[nemises]

(I use "Zoom" on that slider)

[CAT_101st]

:dunno:Well I guss I was wrong.

[Frederf]

If you have throttle on an axis can you smoothly adjust the throttle to positions between the 4 detents?

[slug88]

If you have throttle on an axis can you smoothly adjust the throttle to positions between the 4 detents?

 

Yes.

[Guest]

Yes.

 

Is there any realistic incentive to using this?

[Huckle]

(I use "Zoom" on that slider)

 

Good idea.

 

I have a throttle axis that just opened up too.

[nemises]

Is there any realistic incentive to using this?

 

probably just the fact that that Actual throttle / condition levers are analogue, even though they are used in a "digital" fashion.

 

If you've got Axis to burn (ie a quadrant throttle), then I gues it' be kinda neat, but without spare axis, might as well use pg-up and pg-dwn

[AussieFX]

The engine throttles in the sim (and in the real aircraft) are the two yellow levers at the bottom of the left rear panel. They move through a range, but they have detents to stop them at certain positions. These position correspond to: IDLE (full down), some intermediate posotion whose use still mystifies me, AUTO (used for all dual-engine flight operations), and EMERGENCY (for single-engine flight operations). The throttle levers on the Ka-50 are commonly referred to (on Western aircraft) as ECLs (engine condition levers) or PCL's (power condition levers).

 

During all modes of dual-engine flight, the throttles should be placed in the AUTO position. In this position, engine power is adjusted automatically in order to keep the rotor speed at its nominal setting. If you increase the collective for example, the rotor will try to slow down, which will cause the engines to automatically produce more power in order to prevent this slowdown (called rotor droop). Nearly all modern helicopters now have some form of automatic throttle control in order to increase safety, reduce pilot workload, and increase efficiency.

This Russian system appears to be a little different to "western" systems.

The KA-50 doesn't run the engines at a constant n1 speed as western systems do, I have found that engine speeds can fluctuate anywhere between 85-100% in the KA-50 in auto mode. In western systems the PCL's are pushed to flight idle which then gives the engines 100% rpm or n1 and power output is then controlled by torque which is fundamentally a factor of rotor pitch and torque is the limiting factor for power requirements. I haven't seen a torque gauge in the KA-50 so there are some major differences between the 2 implementations.

[sobek]

This Russian system appears to be a little different to "western" systems.

The KA-50 doesn't run the engines at a constant n1 speed as western systems do, I have found that engine speeds can fluctuate anywhere between 85-100% in the KA-50 in auto mode. In western systems the PCL's are pushed to flight idle which then gives the engines 100% rpm or n1 and power output is then controlled by torque which is fundamentally a factor of rotor pitch and torque is the limiting factor for power requirements. I haven't seen a torque gauge in the KA-50 so there are some major differences between the 2 systems.

 

You are mixing stuff up here, western systems do not run their gas generators at constant speeds, this wouldnt work at different torque settings and probably cause stalls or flameouts. Both systems aim at keeping only the power turbine and hence the rotor at constant speeds, gas generator rpm is adjusted to produce the needed torque through the power turbine. The only real difference in western and eastern equipment is that western systems tend to measure power output by displaying torque (masured through torsion of some part of the gear train with a strain gauge), while eastern counterparts tend to use something like compressor pressure (don't know what it's called exactly, AOS, some help?:))

Edited May 30, 2009 by sobek

[ogiedogg]

Hey, Thanks for the answers, A16 when it comes to the tech. or special tech. you are awsome. I follow your postings and really enjoy reading them... All of everyones replys really helped me understand this dynamic much eaiser. The KA 50 is a different beast when compaired to our Heilos. But hasn't that always been the case with Russian design...... Tks again and lets sticky ths because the PDF sometimes doesn't answer these issues the way they are answered here by you all......

[Franky__]

Incorrect Cat. I have the throttle set to the small slider-control on my Saitek throttle unit (in order to power to idle after landing or throttle to max in case of single engine failure). As a matter of fact that seems to be about the ONLY control I can set that slider to ... but that works. :)

 

And how about Route mode and Descent mode?

I put both to this slider to be as close as possible like in the real heli and they work perfectly. :thumbup:

[AlphaOneSix]

You are mixing stuff up here, western systems do not run their gas generators at constant speeds, this wouldnt work at different torque settings and probably cause stalls or flameouts. Both systems aim at keeping only the power turbine and hence the rotor at constant speeds, gas generator rpm is adjusted to produce the needed torque through the power turbine. The only real difference in western and eastern equipment is that western systems tend to measure power output by displaying torque (masured through torsion of some part of the gear train with a strain gauge), while eastern counterparts tend to use something like compressor pressure (don't know what it's called exactly, AOS, some help?:))

 

Russian helicopters measure the power output of the engine in relation to their limits using an EPR, or engine pressure ratio gauge (EPR is commonly used to determine the relative power output of jet engines). This gauge uses ambient air temperature, ambient air pressure, and air pressure in the compressor section of each engine (specifically, that portion of the compressor immediately prior to the entrance to the combustion section). The ambient air pressure and temperature are used to move the red, inner needles on the EPR gauge on the Ka-50, while the air pressure from the compressor section from each engine is used to move the yellow, outer needles corresponding to each engine. This is not specific to the Ka-50, but rather to the TV3-117 engine (and likely many more models of Russian engines with which I am not familiar).

 

Western aircraft (not just U.S., but European as well) tend to have more interest in the torque being applied to the compressor shaft in the engine, and in many cases, the torque being applied to the main rotor shaft, so they usually have gauges for engine and rotor torques. For the engines, this value is taken on the compressor shaft that is being driven by the gas generator turbine. For the rotor, this is usually taken directly from some part of the rotor mast (drive shaft) within the main gearbox.

 

This difference in design philosophy (torque versus EPR) is sometimes attributed to the West's technological lead in metallurgy. Specifically, the ability of Western engine manufacturers to have such close tolerances on the exact composition of their engine parts allows exact measurements of twisting forces to be made with uniform accuracy across all of their parts. This is not meant to be an insult to the Russian by any means, and I'm not even sure it's true, but the issue from the Russian perspective, I've been told, is that they could not guarantee the exact properties of their metals to the extent required to get the exact same results for twisting forces over thousand and thousand of drive shafts (for example). In other words, since two separate engine drive shafts might have even a very slight difference in composition, they might indicate different torque values for the same power output value, whereas advancements in the metallurgical processes in the West have allowed that same process to be so exact that torque values are a very reliable form of power measurement. This difference may no longer be true in today's world, but remember that these engines were designed in the 1960's.

[sobek]

This difference in design philosophy (torque versus EPR) is sometimes attributed to the West's technological lead in metallurgy. Specifically, the ability of Western engine manufacturers to have such close tolerances on the exact composition of their engine parts allows exact measurements of twisting forces to be made with uniform accuracy across all of their parts. This is not meant to be an insult to the Russian by any means, and I'm not even sure it's true, but the issue from the Russian perspective, I've been told, is that they could not guarantee the exact properties of their metals to the extent required to get the exact same results for twisting forces over thousand and thousand of drive shafts (for example). In other words, since two separate engine drive shafts might have even a very slight difference in composition, they might indicate different torque values for the same power output value, whereas advancements in the metallurgical processes in the West have allowed that same process to be so exact that torque values are a very reliable form of power measurement. This difference may no longer be true in today's world, but remember that these engines were designed in the 1960's.

 

Alpha, i think that strain gauges have to be calibrated through their corresponding signal amplifier by applying a known force to the strained part anyway, so i hardly doubt that any such shaft is perfectly interchangeable without recalibrating the amplifier for the mounted strain gauge. I may be wrong about this (i have not taken the measurement engineering course in my curriculum yet), but i strongly suggest that the reason is a different one. Maybe it goes along the lines of the russians often going for the technically less complicated option (and less expensive, i think), when they are relatively equivalent in other areas. Mounting strain gauges in such a stressful environment (especially heat-wise) is pretty tough, as they tend to drift with temperature and the materials (especially the synthetics used to plaster the strain gauge to the underlying material) are normally vulnerable to environmental stresses.

Edited May 31, 2009 by sobek

[Rangoon]

One small tidbit which I don't think was mentioned regarding the power limit is that this is the most power (given the throttle constraints) that the engine can produce. The governors manage engine power, and therefore rotor RPM, based on the collective pitch setting: more pitch, more drag, more power required. So if you hit the power limit, while you can continue to pull more collective pitch, the engines will no longer answer with more power. You pull more pitch, more drag, *no more power*, so rotor RPM will droop.