Flight Sim’s Obsession with POH Numbers

[mtr75 653]

6 minutes ago, marsman2020 said:

We can control a lot of the variables that cause the large variation in the video above, in sim.  Set 'Clear Skies' and the atmosphere exactly matches the ISA atmosphere.  Turn off all wind.  There is no wear and tear on the engine in the sim. 

So in my mind, we should get closer to POH values in sim then you can in reality.

I agree it's unlikely to be right-on for every value, but I'd expect within 5% for most items, on a Clear Skies day at a sea level field. 

Asobo isn't even close for a lot of things. 

Obviously once you turn on Live Weather, there will be a greater variation.

I didn't realize we got all these Chuck Yeagers up in here! Lol

[mtr75 653]

1 minute ago, Cmcollazo71 said:

Thanks for your insight, this matches the recommendation of the AOPA video embedded above!

 

And I guess this is what I was getting at with this post... I’m not a real world pilot and so information like this is fascinating to me.

Yeah, I mean if you're going to try and clear a 50-foot obstacle at the end of a short field by using book numbers, good luck. I will be watching, not riding along! I know a guy who killed himself and a friend doing exactly that in a 172. 

[marsman2020 1,310]

10 minutes ago, mtr75 said:

I didn't realize we got all these Chuck Yeagers up in here! Lol

People need to stop giving Asobo a pass on this stuff and making excuses for them.  All you have to offer is some throwaway line that covers for Asobo's poor testing, when everything I stated is factually correct.  We can control the sim boundary conditions better than real life, and therefore will be able to repeatably test aircraft in ISA standard conditions in ways that you can't in real life.

Getting the cruise speeds and fuel flows at a given altitude correct so as to produce the correct overall range for the aircraft doesn't require "Chuck Yeager".  It's actually a highly repeatable measurement to make in the sim.  If there is nothing else about an aircraft that is correct, this should be correct because it's 100% repeatable. 

It's not correct for many of the aircraft, and Asobo uses the aircraft vendor range data to generate the range circles in the world map....so you get repeated posts of people planning flights and then running out of fuel.

I'm so tired of this BS people saying we are "obsessed with the POH" when all we want is aircraft that perform reasonably like the real world counterpart in standard conditions. 

 

Edited November 11, 2020 by marsman2020

[wim123 765]

5 minutes ago, marsman2020 said:

People need to stop giving Asobo a pass on this stuff and making excuses for them.  All you have to offer is some throwaway line that covers for Asobo's poor testing, when everything I stated is factually correct.  We can control the sim boundary conditions better than real life, and therefore will be able to repeatably test aircraft in ISA standard conditions in ways that you can't in real life.

Getting the cruise speeds and fuel flows at a given altitude correct so as to produce the correct overall range for the aircraft doesn't require "Chuck Yeager".  It's actually a highly repeatable measurement to make in the sim.  If there is nothing else about an aircraft that is correct, this should be correct because it's 100% repeatable. 

It's not correct for many of the aircraft, and Asobo uses the aircraft vendor range data to generate the range circles in the world map....so you get repeated posts of people planning flights and then running out of fuel.

I'm so tired of this BS people saying we are "obsessed with the POH" when all we want is aircraft that perform reasonably like the real world counterpart in standard conditions. 

 

but aircraft perform differently in the real world all the time, one 172 does not perform the same as another one.

and other ppl get tired of the endless nitpicking by some here.

[Los 416]

3 minutes ago, marsman2020 said:

Getting the cruise speeds and fuel flows at a given altitude correct so as to produce the correct overall range for the aircraft doesn't require "Chuck Yeager".

I agree with this to an extent, how much a certain parameter differs from book will depend on what the parameter is. I was thinking speed because that’s what got me thinking about the topic. Granted running out of fuel at a range that is considerably less than even the average airplane of the type can reach is clearly a bug, but still there there would be some variance.

[Los 416]

1 minute ago, wim123 said:

but aircraft perform differently in the real world all the time, one 172 does not perform the same as another one

After all, isn’t this one thing people love about A2A aircraft, their reaction to how they’re flown and maintained?

That state persistence made each aircraft each pilot’s own. Some took pride in not fouling spark plugs ever, others in seeing how they could still get it airborne after all the abuse they had put it through...

[leprechaunlive 1,861]

1 hour ago, ahsmatt7 said:

Flight sim enthusiasts have long forgotten that POH numbers should be approached as ball park figures. 
 

secondly, flight sim enthusiasts have forgotten that a desk top flight sim should be approached as a ball park idea.

thirdly, I would wager that the obsession comes from the fact hat flight sim enthusiasts are an anal bunch who if it’s not exactly right in ones eyes, then it’s all wrong. Not only that, they will do anything emulate flight because they can’t fly themselves...or just don’t know how to manage money well enough to get a PPL. It’s kind of foolish to be honest. 

Feel better now? 😄

[Manny 1,293]

POH numbers are critical. At TBO at around 2000 hours the Lycoming engine may be a tad inefficient but  we need to use the POH numbers, This is especially critical in IFR.  

From Wiki: "The Cessna 172S was introduced in 1998 and is powered by a Lycoming IO-360-L2A producing 180 horsepower (134 kW). The maximum engine rpm was increased from 2,400 rpm to 2,700 rpm resulting in a 20 hp (15 kW) increase over the "R" model. As a result, the maximum takeoff weight was increased to 2,550 lb (1,157 kg)."

Yes, the default 172 is so underpowered. I doubt it can match any of these "flight gaits" numbers

Performance = Altitude + Power

Edited November 11, 2020 by Manny

[DavidP 1,426]

1 hour ago, SUNDR1V3R said:

What the hell is an Anal Bunch..?

It is a colloquial expression that generally means someone is "fussy". I think you have misunderstood the phrase.

[sd_flyer 6,119]

POH numbers must be pretty close to  real performance otherwise  they can be certified. At the same additional 10-20% safety add to mitigate all other factor. Most of performance calculations I've done in my life were pretty spot on, but I always used rule of thumb to interpolate or round  up to "high number" or "decreased performance" to make up for any errors or other factor. Probably most significant calculation I've done was single engine performance for multi engine training. We always added 15% safety margin per flight school policy and it served me pretty good during every engine out procedures

[2reds2whites 827]

22 minutes ago, wim123 said:

but aircraft perform differently in the real world all the time, one 172 does not perform the same as another one.

and other ppl get tired of the endless nitpicking by some here.

Nitpicking?

It's a flight simulator with aircraft that don't fly anything like the aircraft they simulate.

[2reds2whites 827]

20 minutes ago, Cmcollazo71 said:

After all, isn’t this one thing people love about A2A aircraft, their reaction to how they’re flown and maintained?

That state persistence made each aircraft each pilot’s own. Some took pride in not fouling spark plugs ever, others in seeing how they could still get it airborne after all the abuse they had put it through...

Yes but with A2A there's a method and process to their aircraft.

Asobo have just been throwing darts whilst blindfolded.

[sd_flyer 6,119]

6 minutes ago, Manny said:

POH numbers are critical. At TBO at around 2000 hours the Lycoming engine may be a tad inefficient but  we need to use the POH numbers, This is especially critical in IFR.  

From Wiki: "The Cessna 172S was introduced in 1998 and is powered by a Lycoming IO-360-L2A producing 180 horsepower (134 kW). The maximum engine rpm was increased from 2,400 rpm to 2,700 rpm resulting in a 20 hp (15 kW) increase over the "R" model. As a result, the maximum takeoff weight was increased to 2,550 lb (1,157 kg)."

Yes, the default 172 is so underpowered. I doubt it can match any of these "flight gaits" numbers

I own 172 and have changed 3 type of propellers already. Every prop affect airplane performance in some way. I moves from cruise to climb to a "middle way" prop. Some propeller (I forgot cruise or climbed) easily dashed in csuise passed 2700 rpm  which added extreme stress on the engine  and caused early top overhaul 

[mtr75 653]

32 minutes ago, marsman2020 said:

People need to stop giving Asobo a pass on this stuff and making excuses for them.  All you have to offer is some throwaway line that covers for Asobo's poor testing, when everything I stated is factually correct.  We can control the sim boundary conditions better than real life, and therefore will be able to repeatably test aircraft in ISA standard conditions in ways that you can't in real life.

Getting the cruise speeds and fuel flows at a given altitude correct so as to produce the correct overall range for the aircraft doesn't require "Chuck Yeager".  It's actually a highly repeatable measurement to make in the sim.  If there is nothing else about an aircraft that is correct, this should be correct because it's 100% repeatable.

Disagree. Saying "we can create ISA standard conditions, therefore the planes should be perfect" is fallacy. Do you have the engine leaned properly (for pistons)? Do you have power set properly for the altitude (for turbines)? Are you trimmed properly or are you dragging the plane around the sky? I can think of plenty of variables.

Remember, the most unreliable piece of equipment in the airplane is the pilot.

[Los 416]

3 minutes ago, 2reds2whites said:

Yes but with A2A there's a method and process to their aircraft.

Asobo have just been throwing darts whilst blindfolded.

The method differed, I give you that, but are the results not the same in a way?