Aircraft speed data

[Init]

I haven't searched the forum for info re this topic so I apologize if it has already been discussed.

In the db editor doc it indicates that the Max Speed value shown for ac is in knots.

Is it really knots or is it MPH?

It would appear to be MPH rather than knots since many ac have higher Max Speed ratings in the database than I seen on other datasheets for the same ac. I realize that there can be varying/conflicting data, depending on what sources are used, when it comes to WWII era ac.

I am just curious to know if the speed values for ac listed in the db are really knots or if it is a misprint?

S!
Init

[worr]

Good question. The manual says knots. But what I've been finding in the stock game for US aircraft is MPH numbers instead.

Worr, out

[Init]

That's what I noticed too.

For example, in WitP the A6M2 shows a Max Speed of 332 knots and cruise of 207.

The most reliable data I have found is the A6M2-21 had a max speed of 338mph at altitude and 282mph at SL and a max range cruise of 175mph.

I'm not sure how these differences would affect the outcome of air combat in WitP but it seems like it might skew the results a bit if the values are really knots instead of mph. Of course, if all other ac are over-rated as well then the net would be "0" I suppose.

Init

[worr]

Just glancing at the Zero it does better than MPH

William Green:

A6M2 Zero Model 21 Max Spd: 317 MPH @ 16,400 feet

Anoynomous sources (internet): 332 MPH

But in game max speed 332 knots?

F4F-4 has top speed of 320 and the Zero was faster.

I'll be curising at 160 knots here in a little bit...heading out to a wrestling tournament in Loveland CO in a Piper Commanche...that's 195 MPH.

Worr, out

[el cid again]

I am doing a comprehensive review (field by field) of all Japanese aircraft for CHS - and I have found NO CASE where EITHER full speed or cruising speed are not too fast. In the 30 cases (out of 75) so far examined, the record is 70 knots too fast for full speed - and 30 knots too fast for cruising speed. This amounts to 20% or more for fighter types (that typically are about 60 knots too fast) and about 15% for cruising speeds (that typically are 25-30 knots too fast). It appears these modifications are deliberate, for they come in groups: night fighters and bombers USUALLY are 50 knots too fast, whereas day fighters are 60 USUALLY are 60 knots too fast, and similar patterns for other planes. It seems a violation of the CHS philosophy and an unwarranted advantage for the Japanese. I expect ALL these data to be fixed in the next CHS release, using wherever possible a standardized data set (that is a common reference).

Somewhat compensating this in the opposite direction, I find that MOST Japanese aircraft are not allowed to reach their real service ceilings (which are not absolute ceilings) - although SOME are - and also that virtually ALL Japanese aircraft are not credited with their real rate of climb! In most cases we have "it takes x minutes to reach y thousand feet" data - so we can tell the practical rate of climb to operational altitudes - and invariably the Japanese got underrated in this. That at least should penalize intercept missions, particularly against aircraft at significant altitudes.

Weapons data is a great deal better than speed data, and almost none of it needed to be changed. However, there are some significant exceptions: NIGHT FIGHTERS with NO bomb loads were rated as fighter bombers instead, and several kinds of Zeros were greatly overrated in bomb capacity (only the A6M7 introduced the 551 pound bomb - in 1945!).

Other errors - one CHS added plane - the interesting canard J7M - had its engine rated as a tractor when it is a pusher! [This may matter for damage in the air model - which seems very sophisticated. Maybe this "miracle plane" is not quite so much a "miracle" plane when it is 60 knots slower and you get behind her with a clear shot at her engine! Maybe. Testing will show.] And no Japanese planes have radar - which is very ahistorical for several late war types. Japan had several radars, and some of the modeled types should have them.

[Init]

This is why I asked if the ac speed data as listed in the database is really in kts (as the db editor instrux manual says) or if it is in mph as the data values seem to indicate.

It looks like the database fields were populated (at least in the very few instances I have checked) with mph values and not kts.

I also noticed what you say regarding the rate-of-climb. The A6M2 is much less than it really was for the -21 variant.

BTW - (and I realize that this may cause some here to say, "Where has he been?" but....) what is CHS an acronym for?

Init

[Lemurs!]

The speeds, max altitudes and climb rates for Japanese aircraft are correct.
Wasn't the J7M in the initial Matrix release? I did not think that was a CHS addition.

Most Japanese fighters had engines that were not optimized for high altitude work. When a Zero flys to 32,000ft it can not even bank at 5 degrees without stalling. How much air to air combat can you do under those restrictions? [:)]

Plus, this allows us to show why Japan built Raidens and Shokis. They were made for high altitude work. With the initial Matrix release there was not a ton of reason to build them.

Aircraft speeds are in Mph, this was confirmed from Matrix sources.
Thus, the speeds are correct.

Climb rates are hard to fing for many aircraft so if you can find good, high quality sourcing for an aircraft we may make changes. I love sources that list 2 versions of an aircraft with the same engine, but the second version weighs 500lbs more...,. yet, the sourced climb rate is the same! Not!

What is happening is that the author had no data for the second version and just put the same numbers as the first version. Many people are taking lack of confirmed data as fact.

Mike

[jwilkerson]

Aircraft speeds are in Mph, this was confirmed from Matrix sources.
Thus, the speeds are correct.

Oh boy ... can we spell "pandora's box" ??

I guess I'll fast forward to the open question here - which is - does anyone know whether the stock map is in nautical miles or in statute miles ? Unfortunately, it matters.

The game material says the map is in nautical miles. At the very least ship speeds are in knots. The game material says aircraft speeds are in knots.

Now on to the example ( I'll do this example from stock ):

F4f-3

Endurance: 330 minutes
Cruising Speed: 155 MPH

1. Convert endurance to hours: 330/60 = 5.5 hours

2. Calculate maximum range by multiplying endurance times cruising speed: 155*5.5 (miles/hour * hours ) = 852.5 miles

3. Round down to nearest multiple of 60: 852.5 ~ 840 miles

4. Divide by 60 to obtain maximum range in hexes: 840/60 = 14

5. Multiply by 1/3 to obtain Extended range in miles and hexes: 840*.33333 = 280 and 280/60 = 4

6. Multiply by 1/4 to obtain Normal range in miles and hexes: 840*.25 = 210 and 210/60 = 3

So we taken the game data elements, endurance and cruising speed and calculated the player visible values, of maximum, extended and normal range. All is well ?


Nope. We made an ERROR here !!!

Step 4 is invalid - why ?

Because we divided by 60 NAUTICAL miles. And what we divided into was 840 STATUTE miles. Of course saying step 4 is invalid assumes the map is in nautical miles. We don't know that for sure, but continuing with that assumption to show what happens if we correct the ERROR.

Redoing from step 3.

3' Concert 852.5 statute miles to nautical miles: 852.5 / 1.1508 = 740 n.m.

4' Round down to nearest multiple of 60: 720 n.m.

5' Divide by 60 n.m. to obtain maximum range: 720 / 60 = 12 hexes

6' Calculate extended range: 720 * .3333 = 240 n.m. and 240/60 = 4 hexes

7' Calculate normal range: 720 * .25 = 180 n.m. and 180/60 = 3 hexes

So making the correction, changes the maximum ( ferry or transfer ) range, but does not change the extended or normal range IN THIS CASE. However, in general these ranges might change as well. Hence as I said at the top. It matters, as to whether these values as supposed to be in statute miles or nautical miles.

So this is the first issue. Restated, cruising speed in the database is in MPH however, if the map hexes are 60 nautical miles across, then cruising speed cannot be in MPH but must be converted to knots. Otherwise the ranges calculated by the game are invalid. Fortunately, this is easy to correct in theory, because all we have to do is divide all the cruising speeds by 1.1508 and we are done.

The second issue is Maximum Speed. Above, Lemurs is saying Matrix told us that told us that "aircraft speeds are in MPH" and that is true, we can look at the speeds in stock scenario 15 and compare them to multiple aircraft references and see that they are either dead on or very close if we interpret them in MPH.

We've shown above that cruising speed may need to be changed to knots. So what about maximum speed. If maximum speed is never used in a calculation involving nautical miles ... but only in calculations involving MPH .. then in theory it can stay in MPH ... though it will certainly be confusing for those looking at the data. It would be "nice" if they were in the same units. But in theory that is not required.

A follow on question then will be - are the game calculations which use maximum speed all assuming that maximum speed is MPH ?

[m10bob]

ORIGINAL: jwilkerson

Aircraft speeds are in Mph, this was confirmed from Matrix sources.
Thus, the speeds are correct.

Oh boy ... can we spell "pandora's box" ??

I guess I'll fast forward to the open question here - which is - does anyone know whether the stock map is in nautical miles or in statute miles ? Unfortunately, it matters.

The game material says the map is in nautical miles. At the very least ship speeds are in knots. The game material says aircraft speeds are in knots.

Now on to the example ( I'll do this example from stock ):

F4f-3

Endurance: 330 minutes
Cruising Speed: 155 MPH

1. Convert endurance to hours: 330/60 = 5.5 hours

2. Calculate maximum range by multiplying endurance times cruising speed: 155*5.5 (miles/hour * hours ) = 852.5 miles

3. Round down to nearest multiple of 60: 852.5 ~ 840 miles

4. Divide by 60 to obtain maximum range in hexes: 840/60 = 14

5. Multiply by 1/3 to obtain Extended range in miles and hexes: 840*.33333 = 280 and 280/60 = 4

6. Multiply by 1/4 to obtain Normal range in miles and hexes: 840*.25 = 210 and 210/60 = 3

So we taken the game data elements, endurance and cruising speed and calculated the player visible values, of maximum, extended and normal range. All is well ?


Nope. We made an ERROR here !!!

Step 4 is invalid - why ?

Because we divided by 60 NAUTICAL miles. And what we divided into was 840 STATUTE miles. Of course saying step 4 is invalid assumes the map is in nautical miles. We don't know that for sure, but continuing with that assumption to show what happens if we correct the ERROR.


"Say it ain't so, Joe".....................

[Andrew Brown]

ORIGINAL: jwilkerson
I guess I'll fast forward to the open question here - which is - does anyone know whether the stock map is in nautical miles or in statute miles ?

Statute.


Edit - I thought that I better elaborate on this single word answer: The map, being a flat representation of such a large part of the surface of the planet, is necessarily skewed in various parts. Near the top, it tends to be compressed. Near the bottom, it tends to be stretched. This makes single word answers approximate at best. However, when I started to draw my map, the closest fit I got for drawing the land masses, and for many of the stock map distances, was by using statute miles. My map is drawn specifically based on the value of 60 statute miles per hex.

[el cid again]

Most Japanese fighters had engines that were not optimized for high altitude work. When a Zero flys to 32,000ft it can not even bank at 5 degrees without stalling. How much air to air combat can you do under those restrictions?

Not just Japanese planes - most planes period. Lots of things go wrong at high altitude - air is thin - it is cold - and most planes modeled behave like dogs. Good place to be, though, if you don't want to get intercepted.
Not a bad palce to take pictures from on a clear day - or night. Superb place to be if you need to DIVE on fighters operating some distance below - but still high.

IF you wish to RERATE ALL PLANES for optimum operating altitude - that is worthy of consideration. But you cannot say arbitrarily "we let this plane go to its ceiling but not that one" and claim to be modeling history.
The "service ceiling" of an aircraft is the altitude at which it has a defined minimum rate of climb - 100 feet per minute if I remember right. [The "absolute ceiling" is the altitude at which it has zero rate of climb left]. The "optimum operating altitude" is quite differently, and you will find the ratio between OOA and service ceiling varies quite a lot between types. SOME planes OOA is at sea level! Some planes (e.g. P-39) behave quite well at medium altitude but are dogs at high altitude. This game air combat model MIGHT benefit from using OOA - but we should ask Matrix - and test before we do that.

[el cid again]

Aircraft speeds are in Mph, this was confirmed from Matrix sources.
Thus, the speeds are correct.

I have been working on this for a week - and we have some real programming talent working on it now. Turns out this CAN NOT be true. Not that you didn't check and get confirmation, but it CAN NOT be correct.
However, it is clear someone at Matrix THINKS it is true, as many planes in stock seem to have entered mph vice knot values. Whoever thinks this (a) did not read the manual and (b) does not understand navigation or the stock map (which uses 60 nautical mile hexes). "Range" is NOT entered as a distance value, but a TIME value! The field is called "endurance" and it is measured in minutes! IF you enter cruising speed in mph, the calculation for range is WRONG. And THIS has just been confirmed today.

What we have is badly mixed data - some with knot values - more with mph values - and some of each using inconsistent sources introducing other errors. One "solution" would be to use maximum speeds in mph and cruising speeds in knots - but that is too crazy to advocate and I certainly will not advocate it. Since I have already corrected all Japanese data, it looks like we just need to do the same for Allied planes. At the same time we do that, we can check to make sure other errors are detected.

For those who think there is a problem in the air combat model in the form of fighters are too effective, going over to max speeds in knots not only make us honor the written Matrix manual, it should help get combat results more correct.

[el cid again]

Climb rates are hard to fing for many aircraft so if you can find good, high quality sourcing for an aircraft we may make changes. I love sources that list 2 versions of an aircraft with the same engine, but the second version weighs 500lbs more...,. yet, the sourced climb rate is the same! Not!

Lemurs is right about this. Another issue is that two different rates of climb are commonly given - and those doing data entry for WITP or CHS do NOT know WHICH previous people used. One is called "initial rate of climb" and the other might be called "operational rate of climb." When a plane takes off, it has a better rate of climb than it will have as it gains altitude. The rate of climb declines until it reaches a minimum value so low there is a significant risk of stalling. For those of us who think English, this is 100 feet per minute. At that point you are at the "service ceiling." In my models, I use initial rate of climb, and combine it with a rate of climb correction factor - every thousand feet you go to a lower rate of climb - until you reach the ceiling. For this game, we should use rates of climb determined by calculation from data like "it could reach 15,000 feet in 18 minutes" - what might be called an average rate of climb. Fortunately, this data is generally available. And when it is not, using a similar airframe as a foundation and doing calculations based on differences in power to weight ratios and wing loading ratios is a way to get a reasonable approximation. We know it will be close to this other plane's value, and it will be slightly better (or worse) because of this and that, so we can estimate the value using the same principles we use today with all aircraft before they are built. [All planes fly today in simulation FIRST, so we can get it right.]

[jwilkerson]

ORIGINAL: Andrew Brown

ORIGINAL: jwilkerson
I guess I'll fast forward to the open question here - which is - does anyone know whether the stock map is in nautical miles or in statute miles ?

Statute.


Edit - I thought that I better elaborate on this single word answer: The map, being a flat representation of such a large part of the surface of the planet, is necessarily skewed in various parts. Near the top, it tends to be compressed. Near the bottom, it tends to be stretched. This makes single word answers approximate at best. However, when I started to draw my map, the closest fit I got for drawing the land masses, and for many of the stock map distances, was by using statute miles. My map is drawn specifically based on the value of 60 statute miles per hex.

If the map and the aircraft values are all in MPH then what about the ships ? The ship speeds are in knots and the endurances match source data for nautical miles. So by doing the map in statute miles we "move the problem" to the ships.


But Andrew has confirmed that at least his map, is in statute miles.

But first we will look at example in stock.


Example: Kaga ( stock )

Max Speed: 28 knots ( data in game almost matches Jentschura which has 28.5 knots )

Cruising Speed: 15 knots? ( Japansese warships in stock have had cruising speed set to 15 across the board, more on this later )

Endurance: 10,000 nautical miles ( data in game matches Jentschura which has 10,000 nautical miles )

So ship speed and endurance need to be converted to statute miles.

First, we will convert max speed to statute miles.

1. Convert max speed to statute miles: 28 * 1.1508 = 32.2

2. Convert max speed to statute miles per phase: 32.2 * 12 = 386

3. Convert max speed to hexes per phase: 386/60 = 6.4 ... or truncating fractions 6

( note the previously Kaga's max speed was 28 or 28*12/60 = 5.6 ... or truncating fractions 5

So it does matter. And if stock map is in statute miles, then stock ships have incorrect speed data in nautical miles which would need to be corrected. In general, the ships should be moving a little bit faster on a statute mile map.

Same for CHS, if CHS ships have their speed data in knots and their endurance in nautical miles, then these would need to be changed. And I did briefly glance at CHS ship data and in many cases it matches stock data, so CHS ship data is in nautical miles.

So we still have open question about whether STOCK map is in statute or nautical miles. Andrew has answered that his map is statute.

Regardless of map unit, we appear to have data inconsistency now between ship data ( nautical miles ) and aircraft data ( statute miles ). But it does matter what the map units are. That actually needs to determine everything else. So at least for CHS we know. And thus we know how to resolve inconsistency. We aren't sure for stock since we do not know whether the map was designed in nautical miles or statute miles.

[Ron Saueracker]

BTW - (and I realize that this may cause some here to say, "Where has he been?" but....) what is CHS an acronym for?

Init

C (combined, as in multiple contributors) H (historical, as opposed to historical fiction and complete malarky) S (scenario, or as it seems to have become necessary to some, scenarios plural)

[Mike Scholl]

ORIGINAL: jwilkerson

If the map and the aircraft values are all in MPH then what about the ships ? The ship speeds are in knots and the endurances match source data for nautical miles. So by doing the map in statute miles we "move the problem" to the ships.


But Andrew has confirmed that at least his map, is in statute miles.

But first we will look at example in stock.


Example: Kaga ( stock )

Max Speed: 28 knots ( data in game almost matches Jentschura which has 28.5 knots )

Cruising Speed: 15 knots? ( Japansese warships in stock have had cruising speed set to 15 across the board, more on this later )

Endurance: 10,000 nautical miles ( data in game matches Jentschura which has 10,000 nautical miles )

So ship speed and endurance need to be converted to statute miles.

First, we will convert max speed to statute miles.

1. Convert max speed to statute miles: 28 * 1.1508 = 32.2

2. Convert max speed to statute miles per phase: 32.2 * 12 = 386

3. Convert max speed to hexes per phase: 386/60 = 6.4 ... or truncating fractions 6

( note the previously Kaga's max speed was 28 or 28*12/60 = 5.6 ... or truncating fractions 5

So it does matter. And if stock map is in statute miles, then stock ships have incorrect speed data in nautical miles which would need to be corrected. In general, the ships should be moving a little bit faster on a statute mile map.

Same for CHS, if CHS ships have their speed data in knots and their endurance in nautical miles, then these would need to be changed. And I did briefly glance at CHS ship data and in many cases it matches stock data, so CHS ship data is in nautical miles.

So we still have open question about whether STOCK map is in statute or nautical miles. Andrew has answered that his map is statute.

Regardless of map unit, we appear to have data inconsistency now between ship data ( nautical miles ) and aircraft data ( statute miles ). But it does matter what the map units are. That actually needs to determine everything else. So at least for CHS we know. And thus we know how to resolve inconsistency. We aren't sure for stock since we do not know whether the map was designed in nautical miles or statute miles.

This may not be such a bad thing, as in the real world ships (and especially groups of ships) rarely moved at the speeds most gamers will push them at. When Mikuma pushed into Ironbottom Sound for the Battle of Savo Island at "Flank Speed", he was doing 27-28 knots---as opposed to the 30+ all his ships were rated as capable of. It's not just a matter of fuel consumption, but of maintaining a "manuever reserve"
to enable the outermost ships to keep formation. Having the ships rated in knots, but moving in miles is actually an "error that works" insofar as keeping the game more historical.

[jwilkerson]

This may not be such a bad thing, as in the real world ships (and especially groups of ships) rarely moved at the speeds most gamers will push them at. When Mikuma pushed into Ironbottom Sound for the Battle of Savo Island at "Flank Speed", he was doing 27-28 knots---as opposed to the 30+ all his ships were rated as capable of. It's not just a matter of fuel consumption, but of maintaining a "manuever reserve"
to enable the outermost ships to keep formation. Having the ships rated in knots, but moving in miles is actually an "error that works" insofar as keeping the game more historical.

I was thinking along those lines .. in other words we just "say" that we [ for CHS ] really first converted the ship speeds to statute miles and then "arbitrarily" multiplied all the speeds by about .868 to "slow them down" to more realistic .. less than absolute max on their best day ... speeds.

Then the only issue would be endurance. Endurance is still incorrectly in nautical miles. And to be correct should be increased [ on Andrew's map ]. And most ships seemed to be able to exceed their design endurance IRL when they had to.

Of course "purists" would argue that the game data should be correct to the best of our knowledge - i.e. what is in the books - that is the only way to ensure it is all consistent and there is a point to this. So to borrow one of your earlier arguments...let's get everything correct first .. and then start modifying for effects !!!

[Lemurs!]

What Mike Scholl said.
Listen to him.

Also, near combat you needed to keep some reserve for electrical turrets and ammo hoists.
Also, the game does not model zig zagging so ships are moving to fast in general.
I am an advocate of lowering every ships endurance and cruise speed to help represent zig zagging.

Mike

[Ron Saueracker]

ORIGINAL: Lemurs!

What Mike Scholl said.
Listen to him.

Also, near combat you needed to keep some reserve for electrical turrets and ammo hoists.
Also, the game does not model zig zagging so ships are moving to fast in general.
I am an advocate of lowering every ships endurance and cruise speed to help represent zig zagging.

Mike

Me too.

[jwilkerson]

But if we were going to pick a zigzag/reserve speed modifier ... would have have scientifically just happened to have selected 0.868 ??? It is a convenient choice because this is the size of the "error" we have to correct. But now that we're talking about it - would .75 be a better choice ?