RE: RHS Maneuverability Review

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RE: RHS Maneuverability Review - 9/10/2006 12:01:27 AM

goodboyladdie

Posts: 3469
Joined: 11/18/2005
From: Rendlesham, Suffolk
Status: offline

To get back to the complaints that featured on page 1 in regard to your latest figures:

15 for the P-38J is not supported by any reading I have done on this subject over 30 years. It was an agile fighter - a P-38 group commander once challenged a P-51 group commander to a mock dogfight and beat him on one engine! The P-61 had serious issues - the Northrop test pilot had to do tours to show fighter pilots that this medium bomber sized aircraft was highly agile and could dogfight and had to teach them to fly it as they would fly a fighter. These planes appear to be considerably short changed by your formula. The formula would seem to work for most planes, but witchcraft and educated guesswork will have to cover the anomalies...

(in reply to Drongo)

Post #: 91

RE: RHS Maneuverability Review [Updated] - 9/10/2006 12:05:55 AM

herwin

Posts: 6059
Joined: 5/28/2004
From: Sunderland, UK
Status: offline

quote:

ORIGINAL: Herrbear

quote:

ORIGINAL: el cid again

Here are some sample results:

P-38J=15,

I can understand your rationale regarding 2-engine fighter types before the use of PL and WL. By using these in the calculation, are you sure that you are not penalizing 2-engine fighter types twice? If not, what is inherently unmanueverable about them when combining speed, ROC, PL and WL? I understand reduction added to 4-engine planes as they were not built to withstand excessive G forces. This would impact many 2-engine bombers as well. Are you also saying that 2-engine planes designed as interceptors could not handle the G forces that a single engine plane could?

Three-part answer:

a. Twin-engined fighters can't roll as fast. Hence they can't go into a turn as fast.

b. Twin-engined fighters have to deal with higher stresses, potentially limiting the Gs they can pull.

c. Twin-engined fighters tend to have higher wing-loadings and lower power-loadings, reducing their maneuverability.

_____________________________

Harry Erwin
"For a number to make sense in the game, someone has to calibrate it and program code. There are too many significant numbers that behave non-linearly to expect that. It's just a game. Enjoy it." herwin@btinternet.com

(in reply to Herrbear)

Post #: 92

RE: RHS Maneuverability Review [Updated] - 9/10/2006 12:28:14 AM

Herrbear

Posts: 883
Joined: 7/26/2004
From: Glendora, CA
Status: offline

quote:

ORIGINAL: herwin

quote:

ORIGINAL: Herrbear

quote:

ORIGINAL: el cid again

Here are some sample results:

P-38J=15,

I can understand your rationale regarding 2-engine fighter types before the use of PL and WL. By using these in the calculation, are you sure that you are not penalizing 2-engine fighter types twice? If not, what is inherently unmanueverable about them when combining speed, ROC, PL and WL? I understand reduction added to 4-engine planes as they were not built to withstand excessive G forces. This would impact many 2-engine bombers as well. Are you also saying that 2-engine planes designed as interceptors could not handle the G forces that a single engine plane could?

Three-part answer:

a. Twin-engined fighters can't roll as fast. Hence they can't go into a turn as fast.

b. Twin-engined fighters have to deal with higher stresses, potentially limiting the Gs they can pull.

c. Twin-engined fighters tend to have higher wing-loadings and lower power-loadings, reducing their maneuverability.

Thanks for your answer. I certainly understand your "c" and now El Cid is taking into account of WL and PL in his formula. His formula causes 2-engine fighters to be almost 1/2 as manueverable as a single engine figther. In your estimation, would your "a" and "b" cause that much deviation?

(in reply to herwin)

Post #: 93

RE: RHS Maneuverability Review [Updated] - 9/10/2006 12:48:33 AM

el cid again

Posts: 16922
Joined: 10/10/2005
Status: offline

quote:

ORIGINAL: Herrbear

quote:

ORIGINAL: el cid again

Here are some sample results:

P-38J=15,

I can understand your rationale regarding 2-engine fighter types before the use of PL and WL. By using these in the calculation, are you sure that you are not penalizing 2-engine fighter types twice? If not, what is inherently unmanueverable about them when combining speed, ROC, PL and WL? I understand reduction added to 4-engine planes as they were not built to withstand excessive G forces. This would impact many 2-engine bombers as well. Are you also saying that 2-engine planes designed as interceptors could not handle the G forces that a single engine plane could?

All simulation involves simplification of reality and compromise. There are two different cases involved here:
2 engine bombers pretending to be fighters (see in particular night fighters) and
2 engine planes designed as fighters.

To help the latter - I use a code trick you cannot see in this field - because it isn't in this field.

WITP rates a fighter as better than a fighter bomber in certain respects - and a plane DESIGNED to be a fighter
is STILL classified as a fighter EVEN if it has two engines. On the other hand, a plane that is designed to be a bomber,
or a plane designed to be a fighter bomber that is only a marginal fighter, is rated as a fighter bomber (or a night
fighter).

So to this extent, it is possible - and RHS attempts - to rate these similar looking planes differently.
Further, in all versions of WITP a plane potentially gets its correct speed, rate of climb, and firepower.
Further, in RHS system, engines are a factor in durability - so in this sense a two engine plane ALWAYS has
an advantage over a single engine plane. All else being equal, the 2 E plane is going to have a durability
of 2 more than a 1 E plane (we have a basis calculus and we apply a K factor of 2 to it - so a difference of 1 E
= a durability of 2 points).

One simply cannot understand a modeled plane by looking at a single field. One must consider ALL the values -
and what they mean - even the classification as fighter or not.

It is by no means perfect. Nor even satisfactory. So we keep trying to get it better.

(in reply to Herrbear)

Post #: 94

RE: RHS Maneuverability Review - 9/10/2006 12:58:09 AM

el cid again

Posts: 16922
Joined: 10/10/2005
Status: offline

quote:

ORIGINAL: goodboyladdie

To get back to the complaints that featured on page 1 in regard to your latest figures:

15 for the P-38J is not supported by any reading I have done on this subject over 30 years. It was an agile fighter - a P-38 group commander once challenged a P-51 group commander to a mock dogfight and beat him on one engine! The P-61 had serious issues - the Northrop test pilot had to do tours to show fighter pilots that this medium bomber sized aircraft was highly agile and could dogfight and had to teach them to fly it as they would fly a fighter. These planes appear to be considerably short changed by your formula. The formula would seem to work for most planes, but witchcraft and educated guesswork will have to cover the anomalies...

You are not going to be able to "support by any reading" ANY value for ANY plane in the data set. So to that extent, this comment is meaningless: no one is writing about how we rate planes in WITP except in these threads.
Further - the entire debate about "this plane vs that one" is somewhat misleading:

90% of what matters in air combat - both offensive and defensive - is surprise!!

I can beat your P-38 in a doggie L2D2 IF I see you first - and use that advantage to elect not to engage.

We are talking about the tiny marginal case (statistically) where things get close and nasty. And THEN
what matters most is STILL not the machine - but the skill of the pilots and the initial tactical situation as a whole.

Bear this in mind when you compare a P-38 and a P-51 in some specific pretend dog fight:
I bet that outcome was quite strange and not statistically valid. Certainly no wise P-38 pilot is going to
fight on one engine if he has a choice. And certainly many P-51 pilots could beat a P-38 - at least
sometimes: surely you don't believe it is impossible? This case has a great deal more to do with the
pilots than with the planes. In simulators - where I can program any modern plane on either side -
I do not care what plane you want to take - I will win. I make USAF types furious by flying against them in
"inferior" planes - and showing they might not be as "superior" as they think they are. But I am an anti-air
warfare specialist and I have a whole host of tricks up my sleeve unlikely to be found in most real world
fighter pilots: it says little about the plane except - use something right - it works.

Somehow you have missed an important post by a PhD in this thread: off axis engines are going to impose a penalty due to conservation of angular momentum. This is not the same thing as torque - momentum related to the spin of the engine. There is only one exception: a 2 E plane on ONE axis is not going to have this problem: a Ki-62 would not be counted as a 2 E plane for this reason.

(in reply to goodboyladdie)

Post #: 95

RE: RHS Maneuverability Review [Updated] - 9/10/2006 1:05:37 AM

el cid again

Posts: 16922
Joined: 10/10/2005
Status: offline

quote:

ORIGINAL: Herrbear

Thanks for your answer. I certainly understand your "c" and now El Cid is taking into account of WL and PL in his formula. His formula causes 2-engine fighters to be almost 1/2 as manueverable as a single engine figther. In your estimation, would your "a" and "b" cause that much deviation?

There needs to be some way to determine the effects of engines. This must apply not just to fighters, but to fighter bombers, bombers and transports. It may be there is a better system. In stock and CHS they DOUBLE the number of engines for heavy bombers: that is they divide by 8!!! They use EXACTLY the number of engines for two engine bombers: that is they divide by 2 - and the same for two engine transports. [Lacking 4 engine transports in stock and CHS I cannot say what they do in that case?] But RHS HAS 4 engine transports - and it is hard to see how an LB-30/C-87 is much different from its B-24 parent? So I choose to treat them the same. Similarly, I fail to see how taking a Ventura bomber and making it a night fighter makes it more maneuverable? So I treat them the same. I will consider a different factor - propose one. But remember it must work for ALL cases - not just one plane or one plane type.
I have tried square root of number of engines - and the impact on 4 E planes is not acceptable.

(in reply to Herrbear)

Post #: 96

RE: RHS Maneuverability Review [Updated] - 9/10/2006 2:00:51 AM

witpqs

Posts: 26087
Joined: 10/4/2004
From: Argleton
Status: offline

Sid,

I understand your answer to other folks' questions here, but mine still stands. Should the P-38 be rated that much lower in maneuverability? It's the degree that I'm concerned about. I fully understand angular momentum - that's why I initially said I understand an off-axis two-engine fighter will be inherently less maneuverable than a single engine fighter.

BTW I agree with rating bomber 'night-fighters' the same as the bomber. I just asking about a purpose built high-performance machine.

(in reply to el cid again)

Post #: 97

RE: RHS Maneuverability Review [Updated] - 9/10/2006 2:34:42 AM

Herrbear

Posts: 883
Joined: 7/26/2004
From: Glendora, CA
Status: offline

quote:

ORIGINAL: el cid again

quote:

ORIGINAL: Herrbear

Thanks for your answer. I certainly understand your "c" and now El Cid is taking into account of WL and PL in his formula. His formula causes 2-engine fighters to be almost 1/2 as manueverable as a single engine figther. In your estimation, would your "a" and "b" cause that much deviation?

There needs to be some way to determine the effects of engines. This must apply not just to fighters, but to fighter bombers, bombers and transports. It may be there is a better system. In stock and CHS they DOUBLE the number of engines for heavy bombers: that is they divide by 8!!! They use EXACTLY the number of engines for two engine bombers: that is they divide by 2 - and the same for two engine transports. [Lacking 4 engine transports in stock and CHS I cannot say what they do in that case?] But RHS HAS 4 engine transports - and it is hard to see how an LB-30/C-87 is much different from its B-24 parent? So I choose to treat them the same. Similarly, I fail to see how taking a Ventura bomber and making it a night fighter makes it more maneuverable? So I treat them the same. I will consider a different factor - propose one. But remember it must work for ALL cases - not just one plane or one plane type.
I have tried square root of number of engines - and the impact on 4 E planes is not acceptable.

But should all 2-engine planes be treated the same? Are not planes designed to intercept built and shaped differently than a 2-engine type medium bomber. Certainly speed, ROC, PL and WL play a part and all 2-engine designs apparently are less manueverable than a single engine, but is a 2-engine fitghter and a 2-engine bomber with the same characteristics handle the same?

(in reply to el cid again)

Post #: 98

RE: RHS Maneuverability Review [Updated] - 9/10/2006 3:39:28 AM

witpqs

Posts: 26087
Joined: 10/4/2004
From: Argleton
Status: offline

quote:

ORIGINAL: Herrbear

But should all 2-engine planes be treated the same? Are not planes designed to intercept built and shaped differently than a 2-engine type medium bomber. Certainly speed, ROC, PL and WL play a part and all 2-engine designs apparently are less manueverable than a single engine, but is a 2-engine fitghter and a 2-engine bomber with the same characteristics handle the same?

I believe Sid is agreeing with you. he has noted that planes that are really bombers that have been drafted into the role of night-fighters are being treated like the bomber version.

(in reply to Herrbear)

Post #: 99

RE: RHS Maneuverability Review [Updated] - 9/10/2006 3:49:07 AM

Herrbear

Posts: 883
Joined: 7/26/2004
From: Glendora, CA
Status: offline

quote:

ORIGINAL: witpqs

quote:

ORIGINAL: Herrbear

But should all 2-engine planes be treated the same? Are not planes designed to intercept built and shaped differently than a 2-engine type medium bomber. Certainly speed, ROC, PL and WL play a part and all 2-engine designs apparently are less manueverable than a single engine, but is a 2-engine fitghter and a 2-engine bomber with the same characteristics handle the same?

I believe Sid is agreeing with you. he has noted that planes that are really bombers that have been drafted into the role of night-fighters are being treated like the bomber version.

Yes that is true, but I think he is treating all 2-engine planes the same.

(in reply to witpqs)

Post #: 100

RE: RHS Maneuverability Review [Updated] - 9/10/2006 6:52:45 AM

el cid again

Posts: 16922
Joined: 10/10/2005
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quote:

ORIGINAL: witpqs

Sid,

I understand your answer to other folks' questions here, but mine still stands. Should the P-38 be rated that much lower in maneuverability? It's the degree that I'm concerned about. I fully understand angular momentum - that's why I initially said I understand an off-axis two-engine fighter will be inherently less maneuverable than a single engine fighter.

BTW I agree with rating bomber 'night-fighters' the same as the bomber. I just asking about a purpose built high-performance machine.

Well - maybe not.

This thread is my THIRD try to change the differential - in favor of the P-38 - in response to Rev's complaints about it.

Note that I ALREADY changed this relative differential once - and the proposed new standard moves father in that direction. Further note that the relative difference between dogs with many engines and P-38 is getting wider. That is the most we will ever be able to do: maybe we can make it better - but it is just a question of degree - not an absolute thing.

There is one thing I think may not have been done as I specified - and if that is so the present formula may work a little better (giving us about 1 more point in differential) - but I need to check that. I am trying to do this better.
I am not trying to please P-38 people - just get it relatively right compared to other things. P-38 is never going to rival a F4U-4 in maneuverablity - or a Nate for that matter. Those who think otherwise are never going to be happy with any reasonable formula. And frankly I will never be happy until I have

a) At least three different altitude maneuver factors
b) separate horizontal from vertical maneuver factors

But that is not an option in this version of WITP.

(in reply to witpqs)

Post #: 101

RE: RHS Maneuverability Review [Updated] - 9/10/2006 6:54:45 AM

el cid again

Posts: 16922
Joined: 10/10/2005
Status: offline

quote:

ORIGINAL: Herrbear

quote:

ORIGINAL: el cid again

quote:

ORIGINAL: Herrbear

Thanks for your answer. I certainly understand your "c" and now El Cid is taking into account of WL and PL in his formula. His formula causes 2-engine fighters to be almost 1/2 as manueverable as a single engine figther. In your estimation, would your "a" and "b" cause that much deviation?

There needs to be some way to determine the effects of engines. This must apply not just to fighters, but to fighter bombers, bombers and transports. It may be there is a better system. In stock and CHS they DOUBLE the number of engines for heavy bombers: that is they divide by 8!!! They use EXACTLY the number of engines for two engine bombers: that is they divide by 2 - and the same for two engine transports. [Lacking 4 engine transports in stock and CHS I cannot say what they do in that case?] But RHS HAS 4 engine transports - and it is hard to see how an LB-30/C-87 is much different from its B-24 parent? So I choose to treat them the same. Similarly, I fail to see how taking a Ventura bomber and making it a night fighter makes it more maneuverable? So I treat them the same. I will consider a different factor - propose one. But remember it must work for ALL cases - not just one plane or one plane type.
I have tried square root of number of engines - and the impact on 4 E planes is not acceptable.

But should all 2-engine planes be treated the same? Are not planes designed to intercept built and shaped differently than a 2-engine type medium bomber. Certainly speed, ROC, PL and WL play a part and all 2-engine designs apparently are less manueverable than a single engine, but is a 2-engine fitghter and a 2-engine bomber with the same characteristics handle the same?

To the degree they are better, fighters need to PERFORM better: this must show up as speed, ROC, wing loading, something. We are MEASURING what they really do - and if it isn't better - it isn't. I do not get emotional about numbers - I am a scientist - they are what they are. Yes - treat all 2 engine planes exactly the same - and give advantages to those that are faster or whatever.

(in reply to Herrbear)

Post #: 102

RE: RHS Maneuverability Review [Updated] - 9/10/2006 6:56:27 AM

el cid again

Posts: 16922
Joined: 10/10/2005
Status: offline

quote:

ORIGINAL: Herrbear

quote:

ORIGINAL: witpqs

quote:

ORIGINAL: Herrbear

But should all 2-engine planes be treated the same? Are not planes designed to intercept built and shaped differently than a 2-engine type medium bomber. Certainly speed, ROC, PL and WL play a part and all 2-engine designs apparently are less manueverable than a single engine, but is a 2-engine fitghter and a 2-engine bomber with the same characteristics handle the same?

I believe Sid is agreeing with you. he has noted that planes that are really bombers that have been drafted into the role of night-fighters are being treated like the bomber version.

Yes that is true, but I think he is treating all 2-engine planes the same.

You are both right. And I do treat them all the same - EXCEPT for classification - and THAT matters to code.
But you are not going to see that difference in this field. So it IS going to turn out different in combat - and it is NOT in this field. Understand?

(in reply to Herrbear)

Post #: 103

RE: RHS Maneuverability Review [Updated] - 9/10/2006 9:23:15 PM

herwin

Posts: 6059
Joined: 5/28/2004
From: Sunderland, UK
Status: offline

quote:

ORIGINAL: Herrbear

quote:

ORIGINAL: herwin

quote:

ORIGINAL: Herrbear

quote:

ORIGINAL: el cid again

Here are some sample results:

P-38J=15,

I can understand your rationale regarding 2-engine fighter types before the use of PL and WL. By using these in the calculation, are you sure that you are not penalizing 2-engine fighter types twice? If not, what is inherently unmanueverable about them when combining speed, ROC, PL and WL? I understand reduction added to 4-engine planes as they were not built to withstand excessive G forces. This would impact many 2-engine bombers as well. Are you also saying that 2-engine planes designed as interceptors could not handle the G forces that a single engine plane could?

Three-part answer:

a. Twin-engined fighters can't roll as fast. Hence they can't go into a turn as fast.

b. Twin-engined fighters have to deal with higher stresses, potentially limiting the Gs they can pull.

c. Twin-engined fighters tend to have higher wing-loadings and lower power-loadings, reducing their maneuverability.

Thanks for your answer. I certainly understand your "c" and now El Cid is taking into account of WL and PL in his formula. His formula causes 2-engine fighters to be almost 1/2 as manueverable as a single engine figther. In your estimation, would your "a" and "b" cause that much deviation?

The slow rate of roll reflects the larger angular momentum of an airplane with engines out on the wings. That also produces the larger stresses, since larger aileron forces are needed to produce a given roll rate or maintain a given roll angle. Those two factors could easily result in reduced maneuverability.

_____________________________

(in reply to Herrbear)

Post #: 104

RE: RHS Maneuverability Review [Updated] - 9/11/2006 8:53:15 AM

el cid again

Posts: 16922
Joined: 10/10/2005
Status: offline

Looks like my specifications for the new formula were not entirely followed, so we should see a somewhat greater difference in the data than we see above. What we are doing is increasing the relative importance of loading at the expense of speed - and leaving ROC in the same proportions - which should benefit a hot two engine plane. The correct formula already ran for the P-38 - and it picks up another point.

(in reply to herwin)

Post #: 105

RE: RHS Maneuverability Review [Updated] - 9/11/2006 7:44:35 PM

Herrbear

Posts: 883
Joined: 7/26/2004
From: Glendora, CA
Status: offline

quote:

ORIGINAL: el cid again

Looks like my specifications for the new formula were not entirely followed, so we should see a somewhat greater difference in the data than we see above. What we are doing is increasing the relative importance of loading at the expense of speed - and leaving ROC in the same proportions - which should benefit a hot two engine plane. The correct formula already ran for the P-38 - and it picks up another point.

Can you publish the revised formula?

(in reply to el cid again)

Post #: 106

RE: RHS Maneuverability Review [Updated] - 9/11/2006 10:33:53 PM

el cid again

Posts: 16922
Joined: 10/10/2005
Status: offline

quote:

ORIGINAL: Herrbear

quote:

ORIGINAL: el cid again

Looks like my specifications for the new formula were not entirely followed, so we should see a somewhat greater difference in the data than we see above. What we are doing is increasing the relative importance of loading at the expense of speed - and leaving ROC in the same proportions - which should benefit a hot two engine plane. The correct formula already ran for the P-38 - and it picks up another point.

Can you publish the revised formula?
[/quote

We are still tampering with the formula to insure the correct result range. We want to avoid lots of high ratings - as a way to keep air combat losses down. 36 seems to be a majic number and if possible I do not want to approach it.
Doing this has worked for RHS so far. We want 4E planes in the 3-5 range with 4 as a norm. We want 2 E bombers and transports running around 6-10 and 2 E night fighters and fighters running in the 8-16 area. We want 1 E planes running all the way from about 6 to about 32, depending on if they are real dogs or hot, with 26 a really good early rating for a fighter plane. This is slightly compressed from stock and CHS in terms of the absolute range - because we don't like the effects of very big numbers - and because you cannot differentiate between a fair preforming 4E plane (a B-17) and a dog (an Me-264) if you use values like 1 and 2 (they will all be the same). The formula is approximately:

speed / 30 it used to be speed / 20 and it is maximum speed in mph (I would prefer knots)

ROC / 500 this is INITIAL ROC - the point where it is most different - allowing hot planes to
show off their stuff

Wing Loading with a K this factor must be inverted - as loading goes up manuverability goes down

Power loading with a K this factor must actually be divided into a K factor

Number of engines This factor is used to divide the sum of the other factors - and it appears to be
the proper way to treat engines pending a better mechanism to measure the impact
of conservation of angular momentum for different structures. It meets the WITP
criteria of being simple and remarkably accurate - in spite of its unpopularity.

(in reply to Herrbear)

Post #: 107

RE: RHS Maneuverability Review [New Update] - 9/14/2006 12:54:14 AM

el cid again

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Joined: 10/10/2005
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We have a very satisfactory new formula -

BUT it makes 2 engine fighters - and P-38 in particular - WORSE than they are now
for maneuverability.

We find that the high fraction we give speed BENEFITS these planes relative to
wing loading - which hurts them - they are not good at it.

The new system is very nice - but I fear a firestorm if P-38 actually goes down!
And for the record this review was not intended to have that effect.

Comments please.

(in reply to el cid again)

Post #: 108

RE: RHS Maneuverability Review [New Update] - 9/14/2006 2:18:11 AM

witpqs

Posts: 26087
Joined: 10/4/2004
From: Argleton
Status: offline

Well, as many others who are interested in this mod I am interested in an accurate portrayal. I don't really care about formulas in and of themselves, but obviously they help tremendously with the unimaginable burden to the modder.

Another poster mentioned somewhere above that the most practical route might turn out to be using a formula for the bulk of cases and a bit o' witchcraft and black magic (or words to that effect) for certain cases that defy the formula.

I think we may have arrived at that point. The P-38 seems to be such a case, there might be a very small handful of others (the fewer the better). I do not know exactly what value the P-38 should have, that must be left to others with more data and more knowledge. I know that it was pretty darn good, but that state of the art (and even near state of the art) single-engine fighters of the day were definately more maneuverable. The P-38 had other attributes that helped to compensate.

Also, as I mentioned in a post earlier, the comparison in maneuverability between the P-47 and the P-51 might also benefit from adjusting (to make the comparison more accurate). It's my understanding that the P-51 was more manueverable, while 'The Jug' was more durable.

This brings up another point - does the durability formula consider radial versus in-line engines?

< Message edited by witpqs -- 9/14/2006 2:20:16 AM >

(in reply to el cid again)

Post #: 109

RE: RHS Maneuverability Review [New Update] - 9/14/2006 6:02:01 AM

akdreemer

Posts: 1028
Joined: 10/3/2004
From: Anchorage, Alaska
Status: offline

quote:

ORIGINAL: el cid again

We have a very satisfactory new formula -

BUT it makes 2 engine fighters - and P-38 in particular - WORSE than they are now
for maneuverability.

We find that the high fraction we give speed BENEFITS these planes relative to
wing loading - which hurts them - they are not good at it.

The new system is very nice - but I fear a firestorm if P-38 actually goes down!
And for the record this review was not intended to have that effect.

Comments please.

This would be true in all P-38 models up to the late model J and the L's. Here is a good case of needing to examine what was different: primarily power assisted airelons. All previous P-38's rolled poorly. In a straight up dogfight at speeds over 200kts the P-38L could outroll most fighters. Over 300kts none could roll as fast. Here I am discussing a specific exception to the multiengine rule. Conservation of Angular Motion is only one part of the overall forces effecting roll rate. Single engined aircraft typically rolled worse in the direction opposite of engine torque, as engine torque acts to inrease angular motion in that direction. Conservation of Angular Motion is the primary law of motion only in a closed system. Anything other than a closed system other forces need to be considered.

(in reply to el cid again)

Post #: 110

RE: RHS Maneuverability Review [New Update] - 9/14/2006 1:05:19 PM

el cid again

Posts: 16922
Joined: 10/10/2005
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Durability - defined by me for CHS at a time I was supervised by Joe Wilkerson - a mathmetician and programmer -
uses a number of factors, including

the sheer size of the aircraft (actually square root of the empty equipped weight in pounds divided by 1000)

the number of engines

the number of pilots

the construction of the aircraft itself - including non-metal, partial metal (including just control surfaces of fabric in this category), all metal - and special case (e.g. the geodesic construction of a British bomber, the peculiar cast forward
structure of the Sturmovik, etc)

and the existence of armor (with a very small number of special cases that might be called "extra armor")

There is no consideration of engine type - and not much interest in my part in trying to figure out the engine type
for 249 types of planes. It is probably a monumental task - and not very practical - and in more than a few cases there is more than one kind of engine! We are likely not to know the type for a number of planes.

(in reply to witpqs)

Post #: 111

RE: RHS Maneuverability Review [New Update] - 9/14/2006 1:07:33 PM

el cid again

Posts: 16922
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We have some new data - although I am not sure how we got it? By playing with constants we get:

I am a bit tired, but I wanted to run these numbers by you. I like how
this set came out, let me know what you think. A6M2=28, P-38J=16,
Ki-84=32, F4U-4=40, Spitfire VIII=33, B-24D=4, A5M4=26, P-40E=26,
P-51B=33, Ki-45KAIc=14, J2M2=34

This looks outstanding to me - meeting all my criteria.

(in reply to akdreemer)

Post #: 112

RE: RHS Maneuverability Review [New Update] - 9/14/2006 10:40:48 PM

witpqs

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From: Argleton
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Given AW's statement, should there be a modifier for the rare cases (or case) where the aircraft was equipped with power aerilons?

(in reply to el cid again)

Post #: 113

How he got the new ratings - 9/14/2006 11:37:16 PM

el cid again

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REPLY TO my own "I don't know how we got it:" What he did was increase the absolute value of ROC by 250% while following my instructions todecrease speed by 33% and adding both types of loading. This isn't quite what I thought of - but it may be better than my proposal (which was leave ROC alone). ROC is a great way to distinguish
between a dog twin engine transport or bomber, a moderate twin engine night fighter or fighter bomber,
and a hot twin engine fighter (e.g. F7F, Ki-102 or P-38). The system is remarkably good and meets my
overall perameter limits (4 for a normal 4 engine plane, 3 the absolute dog bottom, 5 for a good performing
4 E plane - so you can tell them from each other; just over 30 for a hot 1 E fighter - so we avoid the code
kill rates at 36 and above; 2 E planes spread out from dogs at 6 to hot at 16).

REPLY TO WITPQS: To this we might add a special case - along the lines of what we do for the Sterling or the Sturmovik in the case of durability - for cause - for the P-38 L. IF the powered alerons matter above 200 knots,
we must give it to all planes. But even if they matter - a dog fight forces loss of energy, altitude and speed on
all participants - so this plane is still at a disadvantage if the f ight goes on - and speed goes down; I don't want
to rate it equal to a 1E plane. The question is: what is the special case effect? Add a point or two to the
maneuverability? Or multiply it times 1.5? Or something else?

AND we need to look for ANY other case of powered alerons. On BOTH sides. IF we adopt a special case.

Note there is a special case not used: A Ki-62 - or a German Pfiel - or a B-34 (I think) - would be rated as one engine planes because the engines have one axis on the centerline.

< Message edited by el cid again -- 9/14/2006 11:39:37 PM >

(in reply to goodboyladdie)

Post #: 114

RE: How he got the new ratings - 9/15/2006 5:57:39 AM

Mifune

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"German Pfiel - or a B-34" I believe you mean the Do-335

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(in reply to el cid again)

Post #: 115

RE: How he got the new ratings - 9/15/2006 7:53:51 AM

witpqs

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From: Argleton
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quote:

ORIGINAL: el cid again

I don't want to rate it equal to a 1E plane.

Agreed.

quote:

The question is: what is the special case effect? Add a point or two to the
maneuverability? Or multiply it times 1.5? Or something else?

I am hoping there is someone out there on the forum who knows enough about the maneuverability of the P-38 versus one of the single engine fighters to give us a comparison. Like "It's a little less than this one" or "It's about equal to that one" or something along those lines. I would be guessing.

If I have to be the one to take a guess, I am willing to do it. I am just hoping someone who knows more than I do can take a swag.

(in reply to el cid again)

Post #: 116

RE: How he got the new ratings - 9/15/2006 8:44:45 AM

ChezDaJez

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From: Chehalis, WA
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quote:

I am hoping there is someone out there on the forum who knows enough about the maneuverability of the P-38 versus one of the single engine fighters to give us a comparison. Like "It's a little less than this one" or "It's about equal to that one" or something along those lines. I would be guessing.

This is from http://www.spitfireperformance.com. It has several P-38 performance tests for the P-38G-L models that were conducted in 1943 and 1944 by the USAAF at Wright Field and in Florida. Here is an excerpt:

quote:

Flight Tests on the Lockheed
P-38J Airplane, AAF NO. 43-28392
Using 44-1 Fuel
I Introduction

Flight test have been conducted at Wright Field on the P-38J-15 Airplane, AAF, No. 28392 at the request of the Power Plant Laboratory, Engineering Division. These tests were made to determine the increased performance of the airplane using the higher powers allowable by the use of 44-1 fuel as compared with the powers allowable with the standard fuel, grade 100/130, Spec AN-F-28. From 6 April to 24 June 1944 approximately 30 hours were flown on the airplane by Major F. A. Borsodi, Major G. E. Lundquiest, Captain Z. D. Fountain, Jr., Captain E. W. Lesch, and Captain J. D. Onerem. Approximately 18 hours were flown on the original engines, the remainder with a new right engine.

II Summary

The P-38J-15 is a twin-engine, high altitude interceptor-fighter. The airplane performs well at high altitude, having a good maneuverability and radius of turn when using maneuvering flaps. The rate of roll is fair at medium speeds and slow at high speeds because of high aileron forces. This is improved in later models by the use of aileron boost.

Unfortunately it doesn't have much data on the L model beyond speed trials at various altitudes. The site does contain performance tests and charts for the P-51 and P-47 plus all variants of Spitfires. It is mainly oriented towards the European theater in aircraft comparisons.

Anyways, read through it and see if it helps.

Chez

< Message edited by ChezDaJez -- 9/15/2006 8:46:29 AM >

_____________________________

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VP-40, Mt View, Ca 1981-87
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(in reply to witpqs)

Post #: 117

RE: How he got the new ratings - 9/15/2006 8:56:43 AM

witpqs

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From: Argleton
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This might answer all your questions...

(in reply to ChezDaJez)

Post #: 118

RE: How he got the new ratings - 9/15/2006 9:01:48 AM

witpqs

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From: Argleton
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quote:

ORIGINAL: ChezDaJez

Anyways, read through it and see if it helps.

Chez

Great site - thanks! The only thing I could gather is that we might have our ROC too low for the P-38 and P-51. Since that is not the current question, I didn't look too deeply into that. As far as the maneuver rating goes, I couldn't tell much. A subject matter expert might.

BTW, regarding that chart (from the site) that I linked to above, it's pretty amazing how some of the altitude/max speed 'curves' are actually zig-zags!

(in reply to ChezDaJez)

Post #: 119

RE: How he got the new ratings - 9/15/2006 9:07:47 AM

witpqs

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From: Argleton
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quote:

ORIGINAL: el cid again
The question is: what is the special case effect? Add a point or two to the
maneuverability? Or multiply it times 1.5? Or something else?

Sid,

Here's my best guess. Considering my lack of expertise in this area, somebody with real knowledge please shoot it down if it's all wet.

I hesitate to say 'multiply it times 1.5' because some plane you find might bust the range limit (up to 30) that you've set. Furthermore, the true modification might be non-linear. Maybe a plane with a higher intrinsic value gets less added-value from the power aerilons?

I suggest adding '7' to the P-38J and L models, making their maneuverability values 21 and 22 respectively.

That is about a 1.5 multiple, but I would be cautious about using that as a general rule. I think 'black magic' is appropriate here.

(in reply to el cid again)

Post #: 120

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