Throttle lag

[Wulf]

Is the throttle lag/response (the delay between moving the throttle forward and the spooling-up of the motor) modeled correctly in the sim (I assume the delay is the same in all the aircraft)?   It seems odd to me that there'd be any delay at all.  The propeller  would have some inertia I suppose and I guess it would produce a bit of drag but would it really be so noticeable? Cars have flywheels and they don't typically have any noticeable delay between throttle movement and engine response.  Why would a 1000-1500 hp motor designed purely for performance take so long to get going?   If these things were turbo powered I could sort of understand it but I thought one of the advantages of a supercharger is that it doesn't cause lag. 

 

Anyway, I'm not an engine guy so I have no idea.  Just askin is all .....

Edited July 3, 2015 by Wulf

[Potenz]

supercharger it is just to give performance at high alts, lag it's pretty normal,a as you start to slam the throttle forward you need a brief moment  for the engine to overcome the extra fuel and star delivering that

extra power

[Wulf]

supercharger it is just to give performance at high alts, lag it's pretty normal,a as you start to slam the throttle forward you need a brief moment  for the engine to overcome the extra fuel and star delivering that

extra power

 

 

Why doesn't that happen with cars or bikes?  F1 engines, as far as I know,  develop close to same hp as the engines in question and yet they don't have a delayed engine response.  It's instantaneous.

 

Given that acceleration can be the difference between life and death for a fighter, I'm just a bit surprised that a 'lazy' engine response time would be acceptable.  

[Wulf]

supercharger it is just to give performance at high alts, lag it's pretty normal,a as you start to slam the throttle forward you need a brief moment  for the engine to overcome the extra fuel and star delivering that

extra power

 

 

 

....... and,  as far as I know, superchargers boost power at any altitude.  However, 'effective' boosting across the full range of service altitudes will require a multi-stage supercharger.

[unreasonable]

Why doesn't that happen with cars or bikes?  F1 engines, as far as I know,  develop close to same hp as the engines in question and yet they don't have a delayed engine response.  It's instantaneous.

 

Given that acceleration can be the difference between life and death for a fighter, I'm just a bit surprised that a 'lazy' engine response time would be acceptable.  

 

I am just guessing here but I would have thought that the weight of the engine parts (and prop) has something to do with it. Modern F1 engines' moving parts must be a small fraction of the weight of those of WW2 aircraft engines. And the prop is much heavier than a set of alloy wheels.

 

Interesting to see your explanation for the phenomenon after you have researched it.

Edited July 3, 2015 by unreasonable

[Wulf]

I am just guessing here but I would have thought that the weight of the engine parts (and prop) has something to do with it. Modern F1 engines' moving parts must be a small fraction of the weight of those of WW2 aircraft engines. And the prop is much heavier than a set of alloy wheels.

 

Interesting to see your explanation for the phenomenon after you have researched it.

 

Well, I really don't now where to go with this.  I'm kind of hoping that a RL pilot of prop planes can tell us if aero engines typically have this delayed engine response thing - as seen in the sim. 

[BraveSirRobin]

Yeah, let's hope that someone looks into that.  In the meantime, I'm going to have trouble sleeping tonight.

[Brano]

Comparing 1.6 litre F1 engine weighing 100kg,running at upper limit of 15k rpm with power output almost 1k hp to aircraft engine of 1940 of 35-40litre weighing 7-8x more with 5x less rpm = ridiculous.

[Edited]

Edited July 8, 2015 by Bearcat

[Wulf]

Comparing 1.6 litre F1 engine weighing 100kg,running at upper limit of 15k rpm with power output almost 1k hp to aircraft engine of 1940 of 35-40litre weighing 7-8x more with 5x less rpm = ridiculous.

Knowing the OP, I do not wonder

 

[Edited]   

Edited July 8, 2015 by Bearcat

[-TBC-AeroAce]

Lag can be very common on engines especially if they have a turbo or supercharger. Gas turbine engines have massive lags ....

[Dakpilot]

It is standard practice with aero engines especially large ones to only increase throttle from min to max in about two seconds. Aero engines of the type in BoS are all very large capacity and will respond slowly even when abused, they cannot be compared to modern, smaller engines, especially when connected to a huge propeller which has to translate that engine power into thrust to overcome the weight/drag of the whole aircraft.

 

Think you should note some of Brano's points before dismissing them out of hand, a BMW engine from an FW190 is nearly 42 litres weighing more than 1 ton with a huge rotational mass, not including the prop

 

Cheers Dakpilot

[Potenz]

in small non high performance bike engines happens, it happens to me every day when i drive my scooter,

i fly a Pa-11 and it has lag too, you slam the throttle and you can notice that lapse of reaction.

 

and again superchargers where used for high alt performance

[Wulf]

in small non high performance bike engines happens, it happens to me every day when i drive my scooter,

i fly a Pa-11 and it has lag too, you slam the throttle and you can notice that lapse of reaction.

 

and again superchargers where used for high alt performance

 

 

As previously noted, I have no in depth knowledge of aero engines and that state of affairs applies to superchargers as well.  What is more, it is possible that we have a different understanding about what is meant when we talk about "high altitude" .  However, to use Spitfires as an example, as far as I'm aware both 'LF' and 'HF' Spitfire types used superchargers.  Spitfire Mks developed purely for low altitude operation, like the Mk XII,  were all, as far as I know, fitted with superchargers, albeit in the case of the Mk XII, a single stage unit (the only supercharger type available for use with the Griffon engine at that stage) .  We also have 'cropped' impeller units in use in these LF types that, as far as I know, were designed specifically to deliver max power at low altitude.

 

As I understand matters, a supercharger can and will be used to augment engine power from takeoff.  Early types were set up to deliver max power at a certain altitude - presumably the altitude where that aircraft type was expected to do most of its flying.  Either side of that altitude the supercharger still provided boost,  but just not as much.  Multi-stage units were developed to provide max power over the widest possible altitude range.  Anyway, that's my understanding.

[Potenz]

As previously noted, I have no in depth knowledge of aero engines and that state of affairs applies to superchargers as well.  What is more, it is possible that we have a different understanding about what is meant when we talk about "high altitude" .  However, to use Spitfires as an example, as far as I'm aware both 'LF' and 'HF' Spitfire types used superchargers.  Spitfire Mks developed purely for low altitude operation, like the Mk XII,  were all, as far as I know, fitted with superchargers, albeit in the case of the Mk XII, a single stage unit (the only supercharger type available for use with the Griffon engine at that stage) .  We also have 'cropped' impeller units in use in these LF types that, as far as I know, were designed specifically to deliver max power at low altitude.

 

As I understand matters, a supercharger can and will be used to augment engine power from takeoff.  Early types were set up to deliver max power at a certain altitude - presumably the altitude where that aircraft type was expected to do most of its flying.  Either side of that altitude the supercharger still provided boost,  but just not as much.  Multi-stage units were developed to provide max power over the widest possible altitude range.  Anyway, that's my understanding.

yes that is correct, maybe i didn't explain my point well enough, sorry.

 

the basics on how a supercharger works is simple compressing air into the engine for a better and faster combustion, high alt doesn't mean only 10000 mts, 

at from 3k the air starts to be very thin so in order to get the best of a engine is a supercharger/turbo compressor. as the air becomes thinner and thinner

its more and more important to increase the air flow into the engine.

 

but about the throttle lag, it's pretty normal in non computer assisted engines

[SCG_Space_Ghost]

The non-linear behavior of the throttles in a couple of these aircraft is a real bother.

[Roo5ter]

When a 1.6 quad turbo engine from 2015 was brought into comparison with ww2 aircraft engines I think we lost any semblance of a thread. That and the insult after this was pointed out which was completely uncalled for and poorly veiled as a 'misunderstanding.'

[Dakpilot]

The non-linear behavior of the throttles in a couple of these aircraft is a real bother.

 

I understood it was only the 109G that had this behaviour, which other A/C are effected?

 

Cheers Dakpilot

[Wulf]

but it happens in cars as well if you go to full throtle in 5th gear check out how slowly it acelerates

 

 

No, that's not the same thing at all.

 

Take the car you're driving out of gear and then rev it.  Does the engine respond immediately or is there a delay?  The engine response is of course immediate.  Have a look at the way model aircraft engines respond to throttle movements. The response is immediate.  Does that mean that full sized aero engines behave the same - no it doesn't.  But I'd still like to hear why that wouldn't be the case.  All I've heard so far is that WW 2 era engines were primitive and therefore had poor throttle response.  That just sounds like complete rubbish to me.   

[Dakpilot]

No, that's not the same thing at all.

 

Take the car you're driving out of gear and then rev it.  Does the engine respond immediately or is there a delay?  The engine response is of course immediate.  Have a look at the way model aircraft engines respond to throttle movements. The response is immediate.  Does that mean that full sized aero engines behave the same - no it doesn't.  But I'd still like to hear why that wouldn't be the case.  All I've heard so far is that WW 2 era engines were primitive and therefore had poor throttle response.  That just sounds like complete rubbish to me.   

 

Read post #11 again ..carefully

 

Cheers Dakpilot

[Roo5ter]

No, that's not the same thing at all.

 

Take the car you're driving out of gear and then rev it.  Does the engine respond immediately or is there a delay?  The engine response is of course immediate.  Have a look at the way model aircraft engines respond to throttle movements. The response is immediate.  Does that mean that full sized aero engines behave the same - no it doesn't.  But I'd still like to hear why that wouldn't be the case.  All I've heard so far is that WW 2 era engines were primitive and therefore had poor throttle response.  That just sounds like complete rubbish to me.   

Dude seriously, if a car is out of gear it's pulling ZERO weight.  When a consumer car has to pull it's own load it doesnt just rev to max instantly when you floor it.  It MIGHT downshift to achieve a higher RPM but it can't just instantly remain in the same gear and wind up.  To reduce the engine load in the same manner on an aircraft that would be the same as taking the prop off of a plane and revving it up.  You can somewhat similate this by maxing the prop pitch out as fine.  It will spin up real fast.  Also you are taking the primitive comments too far I think.  you were looking at a six cylinder engine thats around 1.6 liters and going to have tiny cylinders versus the massive v12 engines and such in the game with large pistons.  The rotating mass of the crankshaft alone is going to be far more than the entire rotating mass of the F1 car because those are designed to rev to the max and swap gears.  It's true fuel injection (and lackthereof) was not as refined as it is you know.... 70 years in the future but I don't think anyone here is attributing this entirely to that.

 

The answers have been posted here that you are looking for, I think the best way to answer any further questions would be to start doing some google research on the basics of engine workings and related mechanics.  I am sure youtube has plenty of videos that show cutaway engines and the process in which they fire and create output.

Edited July 8, 2015 by Roo5ter

[SCG_Space_Ghost]

 

I understood it was only the 109G that had this behaviour, which other A/C are effected?

 

Cheers Dakpilot

 

G-2 is definitely experiencing it the worst - only the last 1/4 of its axis provides substantial output.

 

F-4 seems a little sensitive at the tail end of its axis - especially between 1.3ata and 1.4ata.

 

The A-3 seems to be really sensitive at the tail end of its throttle axis but that could be the fact that we don't feel the throttle detent and the supercharger is kind of jumpy...

 

I don't fly VVS so I can't say.

[Wulf]

This is a pretty poor example because it's difficult to see the actual throttle movements and also because the motor is only running a flywheel, not a prop, but, not withstanding that, the response to throttle inputs appears pretty immediate.  Note, you have to wait till the last minute or so of the vid to see any engine revving.

 

Now, assuming a prop was set to fine pitch (as for takeoff) I see no reason why the engine would behave any differently.  Even if the prop was set to course, I still doubt it would actually slow the run-up to any extent.

 

[Feathered_IV]

Props are heavy things and would take a few moments to accelerate I imagine.  As you say, the video above appears to lack a propellor entirely.

Edited July 8, 2015 by Feathered_IV

[Potenz]

Or [Edited]or he never ever in his life drive any vehicle with a combustion engine, as we all here told you 25 replys, throttle lag its pretty normal

Edited July 8, 2015 by Bearcat

[Roo5ter]

 

 

Dude seriously, if a car is out of gear it's pulling ZERO weight.  When a consumer car has to pull it's own load it doesnt just rev to max instantly when you floor it.  It MIGHT downshift to achieve a higher RPM but it can't just instantly remain in the same gear and wind up.  To reduce the engine load in the same manner on an aircraft that would be the same as taking the prop off of a plane and revving it up.  You can somewhat similate this by maxing the prop pitch out as fine. 

 

 

 

This is a pretty poor example because it's difficult to see the actual throttle movements and also because the motor is only running a flywheel, not a prop, but, not withstanding that, the response to throttle inputs appears pretty immediate.  

 

Now, assuming a prop was set to fine pitch (as for takeoff) I see no reason why the engine would behave any differently. 

 

Amazing deductions you have come forth with.

[Potenz]

This is a pretty poor example because it's difficult to see the actual throttle movements and also because the motor is only running a flywheel, not a prop, but, not withstanding that, the response to throttle inputs appears pretty immediate.  Note, you have to wait till the last minute or so of the vid to see any engine revving.

 

Now, assuming a prop was set to fine pitch (as for takeoff) I see no reason why the engine would behave any differently.  Even if the prop was set to course, I still doubt it would actually slow the run-up to any extent.

 

that video shows all what we said in previous posts mate, take out the prop and you will get extra reaction as you took a heavy weight off the crankshaft

[Wulf]

Okay, this has a chopped prop so not full sized but nevertheless, according to you guys I'd have thought there'd be at least some lag between throttle and engine but I can't pick it up if there is.

 

Also, a flywheel does have inertia.  In that respect it's no different to a prop.

 

And Rooster, I don't have a clue who you are (do you even own the game?) but your overt hostility is beginning to irritate me.  I said from the very outset that I'm not an engine guy.  I simply want to know if the throttle lag in the game is correct or not.  So, continue with the hostility if you wish but don't act all hurt and surprised when I start becoming unpleasant. 

 

 

 

[Potenz]

i think that here is when we have to separate real life from feel less simulation,

what does it says that there's no instant push in game??? in RL it is so noticeable 

because you feel it in your body but actually for an outside viewer there's little to no

clue at all of that instant reaction.

 

Here in sims we don't feel any acceleration forces, so as far as we don't have any

visual clue of that reaction we assume that it isn't there. this is the same examples 

with stall discussions, or some crazy manouvers we perform in sims, and that's just

because we have no body feedback of what we are doing.

[Roo5ter]

  I simply want to know if the throttle lag in the game is correct or not. 

 

 

Now that we have narrowed the issue we can read above and see it has been answered multiple times by multiple people.

 

Yes, I own the game.  As for unpleasant, I love unpleasant which is why I have continued to help answer your questions that have already been answered and suggested a method that you follow to do some personal research to help remedy the source of the problem.  Unfortunately, you would rather continually post question after question that was absolutely nonsensical instead of take a short bit of time to look into the matter when given direction.  You claim to not be an engine guy and just want an answer yet you argue with the answers provided and ignore the facts put forth and ask the same questions all the while confirming you are not an engine guy.  So why argue with the information provided if you are unfamiliar with the mechanics in the first place?  The initial ask seemed reasonable enough but this has become a 'dead horse' scenario.

[Weegie]

Well I'll chip in although I feel the question has really been answered

 

So 2 things

 

1) Engine Revs response

2) Performance increase

 

1) Its not the weight of the prop that's the issue, although it will have some effect on inertia, its the load the prop is generating to create airflow, this is a load acting like a large weight, it will generate its own inertia and so will create a lag in engine revolutions increasing. The lower the load the faster the engine would respond the higher the load the slower

 

The car scenario in 5th gear seems to me a good one. If the prop pitch has 2 positions the aircraft has effectively 2 gears.

 

2) Just like car acceleration the engine has to generate load then overcome the inertia of the weight of the aircraft.

 

All the other stuff stated will also have an effect carbs will be slower to respond, large rotating mass of the engine itself etc:

 

Surely the only time a pilot would slam throttles would be in combat

 

I've driven some older motorcycles that if you whacked open the throttle from near closed to full, you'd bog the engine down, and you would get far better acceleration by smoothly winding the throttle on

[Wulf]

Now that we have narrowed the issue we can read above and see it has been answered multiple times by multiple people.

 

Yes, I own the game.  As for unpleasant, I love unpleasant which is why I have continued to help answer your questions that have already been answered and suggested a method that you follow to do some personal research to help remedy the source of the problem.  Unfortunately, you would rather continually post question after question that was absolutely nonsensical instead of take a short bit of time to look into the matter when given direction.  You claim to not be an engine guy and just want an answer yet you argue with the answers provided and ignore the facts put forth and ask the same questions all the while confirming you are not an engine guy.  So why argue with the information provided if you are unfamiliar with the mechanics in the first place?  The initial ask seemed reasonable enough but this has become a 'dead horse' scenario.

 

 

What?  "Now that we have narrowed the issue"?  Are you high or something or are you just not very good at the comprehension?  I suggest you re-read my original post because until you develop some understanding of the question you're unlikely to be in any position to furnish an answer.  And believe it or not, just because you happen to believe something or other doesn't necessarily make it so.   

 

Despite your angry little interjection, I'm still of the view that the throttle lag in the game is exaggerated.  Nothing I have so far seen suggests otherwise.  If you really care so much about disproving that assertion bring some evidence to the discussion. Your opinions on the topic are absolutely worthless to me.  And furthermore, I have little or no interest in continuing a discussion with someone who only appears interested in provoking an argument.  

[Hoots]

Wulf, you freely admit you have no knowledge of aero engines, have read through several decent responses as to why the lag occurs and you have decided that the game is wrong. The choice is yours of course but it does seem an odd conclusion.

[Roo5ter]

Wulf, you freely admit you have no knowledge of aero engines, have read through several decent responses as to why the lag occurs and you have decided that the game is wrong. The choice is yours of course but it does seem an odd conclusion.

+1

[Potenz]

What?  "Now that we have narrowed the issue"?  Are you high or something or are you just not very good at the comprehension?  I suggest you re-read my original post because until you develop some understanding of the question you're unlikely to be in any position to furnish an answer.  And believe it or not, just because you happen to believe something or other doesn't necessarily make it so.   

 

Despite your angry little interjection, I'm still of the view that the throttle lag in the game is exaggerated.  Nothing I have so far seen suggests otherwise.  If you really care so much about disproving that assertion bring some evidence to the discussion. Your opinions on the topic are absolutely worthless to me.  And furthermore, I have little or no interest in continuing a discussion with someone who only appears interested in provoking an argument.  

mate you need to re read  all the answers given to your OP, for example read what i wrote on post 32

[Roo5ter]

Read post #11 again ..carefully

 

 

The answers have been posted here that you are looking for,

 

 

Or wulf is a troll or he never ever in his life drive any vehicle with a combustion engine, as we all here told you 25 replys, throttle lag its pretty normal

 

 

that video shows all what we said in previous posts mate, take out the prop and you will get extra reaction as you took a heavy weight off the crankshaft

 

 

Well I'll chip in although I feel the question has really been answered

 

 

Wulf, you freely admit you have no knowledge of aero engines, have read through several decent responses as to why the lag occurs and you have decided that the game is wrong. 

 

 

mate you need to re read  all the answers given to your OP, for example read what i wrote on post 32

 

 

 

Can anyone guess the common theme in this thread?  

Edited July 8, 2015 by Roo5ter

[SCG_Space_Ghost]

 

 

 

 

 

Can anyone guess the common theme in this thread?  

 

 

That it went virtually off topic right when it began and that it's turning in to flaming another forumgoer?

[Roo5ter]

That it went virtually off topic right when it began and that it's turning in to flaming another forumgoer?

As you must be talking about when the negativity started as the OP berated Brano.

 

Brano, I assume you rely heavily on online translation software.  No problem there buddy, a lot of people do but you should be aware of the inherent limitations.   If you have any Slovak friends or family members who actually speak English, may I suggest you discuss your proposed comments with them before posting.  Good effort though mate; well done.     

 

As for off topic there are a ton of people stating information to support the OP's topic questions, multiple times over in fact.  So no this is not off-topic.

[SCG_Space_Ghost]

As for off topic there are a ton of people stating information to support the OP's topic questions, multiple times over in fact.  So no this is not off-topic.

 

You can state whatever you want to - being that a quarter of this thread is about motorcycles and car engines... I can't see how they directly correlate to liquid cooled inverted V-12s or 14 cylinder radials... Nor can I see how translating power from the rear axle of a car directly correlates to translating power to a straight crankshaft... Thus, I can't see how anybody has answered OP without themselves drawing unverified or unsubstantiated conclusions.

 

Knowing the OP, I do not wonder

 

And for the record, it was Brano (again) who started with the personal nonsense... Knowing Brano, I'm not surprised.

 

Anyway... Really, /thread

[SharpeXB]

I'm still of the view that the throttle lag in the game is exaggerated.

Based upon what evidence? Do you have any experience operating these WWII aircraft or can you provide actuall evidence on how a real engine installed in one of these planes actually responds?

 

If not then perhaps see Forum Rule #18

http://forum.il2sturmovik.com/topic/3-forum-rules-v102/?do=findComment&comment=12

 

So either provide actual data and post it to the FM suggestions thread or give it up.

Edited July 8, 2015 by SharpeXB

[Weegie]

 

 

You can state whatever you want to - being that a quarter of this thread is about motorcycles and car engines... I can't see how they directly correlate to liquid cooled inverted V-12s or 14 cylinder radials... Nor can I see how translating power from the rear axle of a car directly correlates to translating power to a straight crankshaft... Thus, I can't see how anybody has answered OP without themselves drawing unverified or unsubstantiated conclusions.

 

 

IMHO car and motorcycles have some relevance

 

They are still 4 stroke, engines operating on the same thermodynamic principles, you can throw in fancy terminology like inverted V and 14 cylinders and radials, at the end of the day its an engine, it converts chemical energy to mechanical work. All of them have crankshafts and all are driving shafts

 

The engine does not "see" its load it only "knows" something is acting like a brake on the crank to slow it down and unless more fuel and air is ingested it will slow down. Yes power characteristics are different, but a car on flat road at a given speed is a good analogy for an aircraft flying straight and level in principle, at least as far as the engine characteristics are concerned.

 

God knows how many people have put aircraft engines into cars

Mephistopheles, Chitty Bang Bang, The Beast of Turin, The Napier Railton, Babs are the names that spring to mind, not mention the number of Merlin specials.

 

If the loads and characteristics are so different how on earth did they work?

 

I am not a pilot or had extensive experience, with piston engined aircraft but I have worked on aero GTs doing land and marine duty and engines varying from 250MW power station machines down to small motorcycle engines they share a lot more commonality than you would think and one rule of thumb is the bigger they are the bigger the load they produce but the slower they are to get there.

Edited July 8, 2015 by Monument