New D-9 FM since 2.0?

[Hummingbird]

What kind of data? Prop efficiency, L/D polars? Cooling losses? What was the source of the data?

What prop efficiency figures are you using for the P-51 & Dora respectively? Might shed some light on the matter.

 

And, by the way, I already see the major simplification for this diagram...

 

What of your own then? Says the same thing..

 

Edited December 9, 2015 by Hummingbird

[Yo-Yo]

Then you are missing something :D

 

As clearly depicted on the charts, as well as mentioned by Crumpp, the Dora possesses a turn rate advantage. Thus as long as the Dora doesn't try to maintain a sustained turn below 150-160 knots or so, then it should outturn the P-51.

 

As you can see on the chart the Dora can sustain a 3.3 G turn where'as the P-51D can only sustain a 2.9 G turn. The min turn radius happens at ~165 knots for the Dora and at ~150 knots for the P-51.

 

150 knots for P-51? it means 173.5 mph that greater than the climb speed (160 mph - see POH) only for 8.5%.

 

It is nonsense because in the real world the best turn speed for the planes having max sustained G circa 3 is about 30% percent due to fundamental relations between 1g power curves and loaded power curves.

 

That's why I can not presume these curves as right reference.

[NineLine]

Then you are missing something :D

 

You conveniently cut out his quote from that link, I will paste it again ;)

 

Bottom line is these two designs are very evenly matched in terms of level sustained turn performance. It comes down simply to the skill of the pilot.

[Hummingbird]

You conveniently cut out his quote from that link, I will paste it again ;)

 

I am not saying they are not evenly matched in real life, I am saying they are not ingame :D

 

Thing is they are so evenly matched in real life that Crumpp would've been on the edge trying to follow me, yet he wasn't even close.

[NineLine]

I am not saying they are not evenly matched in real life, I am saying they are not ingame :D

 

Thing is they are so evenly matched in real life that Crumpp would've been on the edge trying to follow me, yet he wasn't even close.

 

I guess the issue then is you havent show that yet, your videos anyways... perhaps you need to be chasing Crumpp?

[ShadowFrost]

Could there also be a possibility that the p-51 or Dora is at an advantage or disadvantage in weight (fuel wise)? Even if not that, depending on which tank the Dora is drawing from the COG can change giving it a disadvantage or advantage overtime. There seems to be a lot of factors that we are currently leaving out of this discussion.

 

Something I might suggest as well is to (I would) have both aircraft recording at the same time and do a side by side view so we can see and compare each aircraft's performance towards the other's at the same time. (Would help ensure a few variables are being met)

Edited December 9, 2015 by ShadowFrost

[Hummingbird]

Could there also be a possibility that the p-51 or Dora is at an advantage or disadvantage in weight (fuel wise)? Even if not that, depending on which tank the Dora is drawing from the COG can change giving it a disadvantage or advantage overtime. There seems to be a lot of factors that we are currently leaving out of this discussion.

 

Something I might suggest as well is to (I would) have both aircraft recording at the same time and do a side by side view so we can see and compare each aircraft's performance towards the other's at the same time. (Would help ensure a few variables are being met)

 

We'll do what we can. I am willing to do the tests with others as well as Crumpp is going to be away for the next 4 days.

 

Next time we will have voice comms as well which will significantly simplify matters.

[ShadowFrost]

I would be more than happy to help you in the future, I fly all almost all DCS modules and I would be more than glad to help in any way I can to make sure that the aircraft are modeled correctly to their real life standards. PM me in the future if you want my help.

[Hummingbird]

I would be more than happy to help you in the future, I fly all almost all DCS modules and I would be more than glad to help in any way I can to make sure that the aircraft are modeled correctly to their real life standards. PM me in the future if you want my help.

 

Many thanks! How do you feel about some testing this friday? :)

[Hummingbird]

Next video is up.

 

Note: This was the only test we did with me being the chaser, and unfortunately it wasn't coordinated well because of a lack of voice comms. So all I can say is that I was trying my outmost to stay on Crumpp's tail and if possible get some deflection for a gun solution. I don't know if Crumpp was trying his hardest, but it didn't seem to matter regardless.

 

yZ4XdW4aZ2o

[Crumpp]

What kind of data? Prop efficiency, L/D polars? Cooling losses? What was the source of the data?

 

And, by the way, I already see the major simplification for this diagram...

 

Simple but very very powerful.

 

The math is acceptable for predicting aircraft performance. It does accurately predict performance within normal margins of error. It is the BGS system and is taught in every major engineering curriculum in the United States.

 

No it is not the "be all end all of performance predictions anymore than any other system in existence is the "spot on accurate" predictor of specific performance. It does tell you what are probable performance trends for the flight conditions analyzed.

 

MinDrag points and L/Dmax matches the POH speeds too in the analysis which I why I used it.

 

BTW, Focke Wulf used Carson's Speed for cruise speeds in the POH. If you are trying to align your L/D curve to Flugzueg Handbuch figures it will be difficult without knowing that.

 

The power available and propeller efficiency we can argue. I do however have thrust-horsepower charts for the Dora and prop efficiency charts for the P-51. I would be happy to share them. There is not much to choose as Aeroproducts, VDM, and Hamilton Standard all could produce a good propeller. So I would be very surprised if there was significant difference in them.

 

Hummingbird,

 

This is not supposed to be an adversarial discussion so do not make it one.

 

There is room for interpretation in the math and anybody that tells you differently is flat out wrong. That is why our sims at the training department cost millions of dollars and still cannot accurately reproduce some portions of the aircraft's behaviors/performance.

[Hummingbird]

Hummingbird,

 

This is not supposed to be an adversarial discussion so do not make it one.

 

I am not, I simply trying to discover the heads and tails of it all. I mean both your charts and Yo Yo's own charts show that what we experienced shouldn't have happened, thus I am confused why it isn't being acknowledged... I mean the footage is there, and everyone can test this out for themselves as well.

 

There is room for interpretation in the math and anybody that tells you differently is flat out wrong. That is why our sims at the training department cost millions of dollars and still cannot accurately reproduce some portions of the aircraft's behaviors/performance.

 

Oh I know, hence why I was asking about the prop efficiency figures as Yo Yo seems to suggest they are better for the Mustang, which I cannot understand.

 

I mean doing the basic math in terms of top speed vs drag vs available engine power, the P-51 doesn't have a more efficient prop. It's pretty much identical actually :huh:

[eekz]

I'm sorry to ask, but it seems that at 380km/h P-51 and FW190 turn rates are relatevely equal, and thus aircraft mass should be the defining factor (if piloting is ideal) as it affects accelerated stall characteristics. Am I right? If yes, then there should be mass parameter in your graphs.

Edited December 10, 2015 by eekz

[Nedum]

Yesterday I did a test with the P51D in 1.2.6 and 2.0.

In 1.2.6 it was a good and "fair" fight against the D9. In 2.0 it was like shooting fish (D9) in a barrel.

I was able at any speed and at any height to pull much more AoA with the P51D as with the D9 without losing any control.

The P51D is right now an UFO against the D9 in 2.0.

 

The difference is so huge I can't believe that you guys need charts to see that! :(

The power of the P51D is amazing compared to the D9 in 2.0.

The D9 has big problems with Pitch movements. An extreme loss of speed all the time. If I try to make a clear/good loop, the D9 flips over the wing tips because of the enormous loss of speed. If I pull harder to make the loop looking good, the D9 drops out of the sky with all her speed lost. I can't pull her around without flipping her over the wings as in 1.2.6. I know this behavior but this was an extreme old one (D9 beta).

In 1.2.6 the D9 behaves like in a dream. With 2.0 she behaves like a fat turtle and I don't know why! :cry:

2 dogfights against the P51D AI (excellent) in 1.2.6. 2-5 Minutes with an easy victory each time for me with the D9.

2 dogfights against the P51D AI (standard/ quick mission D9). Both times I was running out of gas. The P51D was the whole time in an advantage position but couldn't fire at me, at the same time I could try what I wanted, I was never able to get in a fire position at her six. Ok I am not the best pilot with the D9 but why can I outfly her so easily in 1.2.6 and fly much harder maneuvers without loosing the control and without loosing so much speed? :helpsmilie:

I do not need any graph to see that here is something extreme wrong. If not with the P51D then with the D9.

1.2.6 versus 2.0 will show you how huge the difference is. If you can't see/feel it yourself, then I think a video will do it not any better!

Edited December 10, 2015 by Nedum

[Nedum]

Next video is up.

 

Note: This was the only test we did with me being the chaser, and unfortunately it wasn't coordinated well because of a lack of voice comms. So all I can say is that I was trying my outmost to stay on Crumpp's tail and if possible get some deflection for a gun solution. I don't know if Crumpp was trying his hardest, but it didn't seem to matter regardless.

 

yZ4XdW4aZ2o

 

Looks like they have changed/flipped the FM inbetween the P51D and the D9?

Shouldn't it be the other way and the D9 gets in a better postion with each turn?

But that's exactly how I see it in every fight.

Edited December 10, 2015 by Nedum

[Echo38]

First video is up, however sadly there was no sound captured, so I put in some music to hopefully make it a little less boring to watch.

 

Two things. First: I noticed that your turns weren't coordinated; you were in a slight/moderate slip the entire time. While that amount of slip shouldn't make a very large difference, it does hurt your sustained turning ability. I don't know if it could mean the difference between out-turning or not, in this case, but those graphs make it look like a pretty close thing, so it just might. It would be best if you keep the ball centered in all future tests.

 

Second thing: what was the song?

 

The Mustang simply cannot sustain (+)3G at 200 knots yet it is doing it.

 

What fuel loads were the tests conducted at? How about ammunition? Any other variables you can think of? Yo-Yo's graph shows it to be close enough that it wouldn't take much to tip the balance.

 

I'm sorry to ask, but it seems that at 380km/h P-51 and FW190 turn rates are relatevely equal, and thus aircraft mass should be the defining factor (if piloting is ideal) as it affects accelerated stall characteristics.

 

In a sustained turn, at sea level, at best sustained turn speed, you aren't nearly close enough to exceeding maximum angle of attack for stalling characteristics to matter.

Edited December 10, 2015 by Echo38

[NineLine]

You dont give enough info to know if the testing you did was equal between the two very different terrains...

 

Yesterday I did a test with the P51D in 1.2.6 and 2.0.

In 1.2.6 it was a good and "fair" fight against the D9. In 2.0 it was like shooting fish (D9) in a barrel.

I was able at any speed and at any height to pull much more AoA with the P51D as with the D9 without losing any control.

The P51D is right now an UFO against the D9 in 2.0.

 

The difference is so huge I can't believe that you guys need charts to see that! :(

The power of the P51D is amazing compared to the D9 in 2.0.

The D9 has big problems with Pitch movements. An extreme loss of speed all the time. If I try to make a clear/good loop, the D9 flips over the wing tips because of the enormous loss of speed. If I pull harder to make the loop looking good, the D9 drops out of the sky with all her speed lost. I can't pull her around without flipping her over the wings as in 1.2.6. I know this behavior but this was an extreme old one (D9 beta).

In 1.2.6 the D9 behaves like in a dream. With 2.0 she behaves like a fat turtle and I don't know why! :cry:

2 dogfights against the P51D AI (excellent) in 1.2.6. 2-5 Minutes with an easy victory each time for me with the D9.

2 dogfights against the P51D AI (standard/ quick mission D9). Both times I was running out of gas. The P51D was the whole time in an advantage position but couldn't fire at me, at the same time I could try what I wanted, I was never able to get in a fire position at her six. Ok I am not the best pilot with the D9 but why can I outfly her so easily in 1.2.6 and fly much harder maneuvers without loosing the control and without loosing so much speed? :helpsmilie:

I do not need any graph to see that here is something extreme wrong. If not with the P51D then with the D9.

1.2.6 versus 2.0 will show you how huge the difference is. If you can't see/feel it yourself, then I think a video will do it not any better!

[zantron]

Have you guys been doing these tests at equal above sea level (opposed to AGL)? On black sea and neveda maps that is

[Echo38]

Have you guys been doing these tests at equal above sea level (opposed to AGL)? On black sea and neveda maps that is

 

The videos they've posted showed the unexpected phenomenon occurring at sea level, so that isn't the problem, at least in the test shown. The graph shows sea level, their test video was at sea level, and the disputed point is sea-level sustained turns.

 

I wasn't going at 350 at any point, I was following his chart's recommendation of staying between 365 to 380 km/h. Also again, according to Yo Yo's chart I would actually be slightly outturning him at all these speeds: 350, 365 or 380, yet he could at any point turn inside me the entire time at all those speeds. At no speed could I pull enough rate to prevent him from maintaining a gun solution.

 

If you're doing more tests, I have another recommendation: try turning at 375 KPH for at least four full circles. Here's why:

 

When doing sustained turns below best sustained turn speeds, if you unload slightly to increase your speed to best speed, your opponent can temporarily gain on you as your turn widens. It can take some time for the superior turn rate to start making a visible difference. I don't know that this was the case in the videos, but I did see your IAS drop down to about 355 a few times. So, at least at some points, you appeared to be below the desired speed. After raising it back to the best speed, I'm not sure you performed enough turns at the higher speed for it to really start to matter; Crumpp may have still had a slight excess of energy (gained while you were below best speed). Not that I think that this is enough to cause the apparent discrepancy we're seeing, mind you, but every little bit helps.

 

In other words, I suspect the following scenario may have occurred: while you were turning below best sustained turn speed, Crumpp was able to match you and even gain a bit of excess energy (without gaining enough speed to exceed his own best sustained turn speed). After you raised your speed back to best speed, Crumpp spent the stored E to stay with you for a while longer (which would mean that he wasn't quite down to a sustained turn at this point). With your ball centered, you might've eventually started to gain on him, but you quit the circles before that point.

 

Again, it's hard to say without having been in one of the aircraft, but I'm wondering if you would have been able to out-turn Crumpp long-term if you'd A) kept your ball centered, B) stayed at the upper end of the recommended speed range, for the entire time, and C) performed enough 360-degree circles for any E advantage Crumpp might have had to dissipate. If the result is the same (P-51 out-turning FW 190) under those conditions, and the fuel/ammo loads were the same as the airplanes in Yo-Yo's graph, then I can only agree that the tests don't match the graph. However, as it is, there still remains some doubt.

Edited December 10, 2015 by Echo38

[Nedum]

You dont give enough info to know if the testing you did was equal between the two very different terrains...

 

Yeah I see that!

The reason is if I take a deeper look at YoYo's charts I can see that this behavior isn't/shouldn't be any near possible.

 

I will test it again with 1.5 versus 2.0!

Edited December 10, 2015 by Nedum

[Nedum]

Have you guys been doing these tests at equal above sea level (opposed to AGL)? On black sea and neveda maps that is

 

The Vids from Hummingbird and Chrump are at sea level with 1.5. Here is the P51D outperforming the D9 with ease too but I should be by 100% the other way around!

But a "yes" to your question!

I will test the D9 versus P51D in 1.5 after work and 1.2.6. at the same level.

But even then should the D9 should have a slight advantage.

right now I fly circles around the D9 with the P51D. That's a bit hefty for me for my thoughts.;)

[eekz]

In a sustained turn, at sea level, at best sustained turn speed, you aren't nearly close enough to exceeding maximum angle of attack for stalling characteristics to matter.

 

Then how do you know that this turn has best time the plane can do if you don't have such a limitation? According to this if a plane is not exceeding max AoA or G that cause stall then it can turn faster.

Edited December 10, 2015 by eekz

[Echo38]

Not faster. It can turn tighter, but if you slow down below the best sustained turn speed, you'll complete your (tighter) turn in a longer time. Pulling max alpha gives you the tightest turn you can make, but, unless you're burning excess energy (e.g. a diving turn, an instantaneous turn at "corner" turning speed--which is very different than best sustained turn speed), it isn't the turn that you can make in the shortest time.

 

In other words: if you are in a sustained turn, at best sustained turn speed, and you increase your angle of attack, you will slow down and turn tighter, but your turn will take a longer time to complete. That's what makes "best sustained turn speed" the best sustained turn speed: by definition, it's the speed at which you make a sustained turn in the shortest possible time. (There's probably a less clumsy phrase to use instead of "best sustained turn speed," but I don't know it.)

Edited December 10, 2015 by Echo38

[eekz]

But wait, wing loading affects turn rates of planes, so initial aircraft mass does matter.

Edited December 10, 2015 by eekz

[Echo38]

Mass always matters, in turning. I'm not sure what you're getting at.