RHS 6, 5 & 7.7612 Microupdate Update (nonessential)

[el cid again]

At first I thought this would be an eratta update - and mostly it is just that. But some of the eratta are pretty irritating - in particular the case of some independent tank companies that want to grow into divisions and Warspite wanting to replace its 15 inch guns with minor secondary type. A number of Japanese ships with 75mm SP guns is not nice either - but you might rationalize that by saying their crews were not good at AAA! That problem caused a review of ships to insure there were no unreported cases. Seems we often had the class and ships in sync - but still wrong - and error checkers cannot tell such a case is wrong. The review led to discovery of a few other useful changes - which were not always eratta - but would be better simulation if done. Thus a ML with ASW capability is reclassified as an MLE, and some late war EOS/AIO ships get revised AA per the standards written in the RHS manual. On the side, before this got complicated, I added 10 USN LSTs which were missing, and an LCM group to Asiatic Fleet.

More comprehensive is a problem with US fighters (and, it turns out, bombers and some transports) command assignments. That forced a review - which can be done properly as I have every squadron record. That is permitting reviewing of data inherited as well as entered by the RHS team - and we are doing several things here:

a) Dividing the scenarios into two groups - political point options (PPO, EOS and AIO) and non-political point options (CVO, RAO, BBO and RPO). The first group gets their planes at Salt Lake City one day after they leave the Eastern USA - assigned to Western Command. The second group gets their planes at a forward base, assigned to the command for that base. This base is either historical, or it is the nearest allied airfield on the map. [For New Guinea we use Port Moresby - since we don't know if Dobradura or other points will be developed or not? For Australia and India we get pretty close. But for Tinian or similar, we use Pearl Harbor - because we don't know if Tinian will be Allied or not in any given game. That sort of thing.]

b) Reviewing the aircraft assigned. Numbers of B-29 squadrons should start as B-26 and upgrade to B-17. Numbers should start as B-17G and upgrade to B-29. There may be other cases not yet discovered. [Note how the often repeated charge in the Forum that players are "wrong" to upgrade 2E bombers to 4E bombers is out of sync with USAAF practice - which was to do exactly that. IF you have the bombers to upgrade to - it is perfectly historical play to do so.]

There were a few other eratta, but the vast bulk are ship class and air group changes. However, there is some development here, the strictly historical scenarios should be easier to play (as you don't have to pay pp for so many squadrons and you start forward unless you don't own the field), and the number of changes is significant enough to warrant notice. More eratta apply to EOS and AIO, while more enhancements apply to CVO, RAO, BBO and RPO (with PPO deliberately not on either list).

AIO is a very strange case, technically speaking (AI being a very strange creature). It is in the EOS and PPO family in terms of ALLIED air group assignments (home commands) - but in the CVO/BBO family in terms of JAPANESE air group assignments (forward commands) - to help AI "know" where things should be or go? Similarly, it is in the EOS and PPO family in terms of ALLIED political points, but in the CVO/BBO family in terms of JAPANESE political points - since the AI does not use vast numbers of them - and since we assign land and air units to forward commands to help the AI. Changing these political points (for Japan) is NOT recommended - it is tied to THOUSANDS of fields for technical reasons.

OK - the plan: as soon as the US air unit review is completed, we will issue this update, which is becoming semi-important. It seems perpetually to be "tomorrow" - but it might occur today - depending on what we find - and what else might be reported. We are working in everything we hear about - if it turns out to be a problem (not all things that seem wrong are wrong: Japanese ARMY ships DO use Japanese ARMY guns for example).

There is an associated (already released) pwhex file update - fixing a blocked Kokota Trail. This can and should be used in any game or test that is ongoing.

Updates related to Allied plane art are on indefinite hold - until we get the art. That update will apply only to EOS and AIO, and it will permit more flexability in upgrading planes - and might add planes (or empty slots).

Updates related to the Monsoon Map are on indefinite hold - we will get to it when other things are not taking my time. The art exists - but the pwhex is a bear - and I am not working on it. Winter maps are even farther out. Both will ONLY be done for Level 7.

[mlees]

Dunno if you already know this one:
 
I have the latest (Aug 25 2007) version of RHSCVO 5.76, scenario #50 downloaded.
 
USS Marblehead, starting the game in Tarakan, has two floatplane squadrons embarked, (3/VCS-3 and 4/VCS-3) exceeding it's capacity.
 
USS Trenton, in Panama, has nada.
 
I assume one of those Marblehead squadrons should be on the Trenton...

[el cid again]

3/VCS-3 ahould be on Trenton.

[el cid again]

We have found interesting material on USAAF Photographic recon squadrons. Those we added for the F-7 (an ultra long range recon only B-24) can in some cased be moved from late game curiosities to start of game units - 2nd is at Spokane from January 2nd, 1942 and 4th is at San Francisco when the war begins. Both helped map Alaska - so can be Alaska Command - and both used a variation of the B-18 - called F-2. This was armed with 10 x 100 pound bombs - not the usual armament - but not nothing either. A number (4?) of others should start with B-25s, and I am taking out their offensive bombloads. But I wonder if they also carried a reduced bomb load? Any data? Unless we created a special type - which we did for the F-7 - and which we may do if we gain some slots when we consolodate after getting new plane art (EOS/AIO only) - we cannot increase the range - drop tanks won't work at the unit level (drat). So if they can be armed - they should be - given they won't fly to greater ranges.

43 Photographic can use the B-18 as well - it had many types - but we have B-18 and now a recon variant of it in the sense I know how to arm it. This unit should start the war at Pearl Harbor - but does not. I also have added the recon conversions of B-18 to the pool - to support these units mainly. That they can support bomber units is acceptable - a former bomber could have the camera's ripped out - and be returned to bomber service. Or to ASW service - in the case of the unit at Panama with ASW loadout.

[m10bob]

B 25 models including photo-recon models:

http://www.xs4all.nl/~fbonne/warbirds/w ... rtb25.html

[el cid again]

Thanks. My guess was pretty good: I put a "drop tank" internal - in the bomb bay - and they did too. It won't work in the game (at least not unless code is changed) - but it will increase the fuel cost per mission - and it won't drop bombs - and that is close to right. And if you assign a recon B-25 to patrol missions - it will manage to "kick out the door" a DC from time to time.

[el cid again]

All identied matters have been addressed - and we hope there is nothing too irritating to tolerate for longer term use at this point. We will collect eratta if detected - but the focus is on detecting problems in testing - and moving on to the point we may consider other things. We do not plan to do an OIO at this time - lacking a clear sense of consensus about what it should entail - and the proposal for a quick modification not involving vast data changes not resounding very well. What might lie ahead is an enhancement for EOS/AIO if new air art ever completes for the Allies - and a Monsoon pwhex file (think "tropical trails vaporize, but rail lines remain" and you have a sense of it).

Level 5 will follow. Level 6 was also updated - regretfully - meaning 21 scenarios were corrected - because it was not good enough to consider it the final form. Hopefully this is the last update for 6.

[witpqs]

Sid,

Over the past couple of days I've noticed what I believe is a problem with the climbing rates of certain allied fighter upgrades, namely in the P-47 and P-51 families. In RHS right now their climb rates are:

P-47D=3120
P-47N=2700

P-51A=2770
P-51B=1852
P-51D=2400

What caught my eye is that the initial model has the greatest climb rate, while the follow on models were made with better engines and improved propellers that were supposed to provide better climb rates (among other things).

I used a link that someone on the forum provided to wwiiaircraftperformance.org to see several original source documents from flight testing. The P-47 N model is compared against the D model and shows significantly better climb rate.

Here is a scan of an original document dated 6 October 1944 and labeled "Comparison of P-47D, P-47M and P-47N Performance".

http://www.wwiiaircraftperformance.org/p-47/comp-p47dmn.jpg

Here is a page where that data and more from other documents is retyped for easier legibility:

http://www.wwiiaircraftperformance.org/p-47/p-47.html

Because I do not know what altitude you are using as a standard for climbing rate, you will have to look at the document yourself to choose the appropriate climb rates for the D and N models. However, at all altitudes it is clear that the P-47N outclimbs the P-47D.


Regarding the P-51, the site has data for the P-51B model, and shows the climb rate was much better that the anemic rating of 1852 ft/min currently in the scenario database.

Here is a page with various original source data re-typed from documents dated 18 May 1943:

http://www.wwiiaircraftperformance.org/mustang/mustangtest.html

Here is an original graph of climb data:

http://www.wwiiaircraftperformance.org/mustang/p51b-12093-climb.jpg

This original source chart was already shown on the forums:

http://www.wwiiaircraftperformance.org/p-38/fighter-comp-chart.jpg


Recommendations

As I noted above, I cannot give you a specific number because I do not know exactly which climb rate you use in RHS, but certain actions are clear:

1) Reduce climb rate of P-47D.
2) Increase climb rate of P-47N (should be a value even greater than P-47D is now).
3) Increase climb rate of P-51B (possibly to about twice the current value).
4) Reexamine climb rate of P-51D if you have other sources. It almost certainly is much greater than currently in the database (2400 ft/min), presumably greater than the P-51B (after the P-51B is increased).

[el cid again]

Level 5 scenarios are in the upload process.

[el cid again]

ORIGINAL: witpqs

Sid,

Over the past couple of days I've noticed what I believe is a problem with the climbing rates of certain allied fighter upgrades, namely in the P-47 and P-51 families. In RHS right now their climb rates are:

P-47D=3120
P-47N=2700

P-51A=2770
P-51B=1852
P-51D=2400

What caught my eye is that the initial model has the greatest climb rate, while the follow on models were made with better engines and improved propellers that were supposed to provide better climb rates (among other things).

I used a link that someone on the forum provided to wwiiaircraftperformance.org to see several original source documents from flight testing. The P-47 N model is compared against the D model and shows significantly better climb rate.

Here is a scan of an original document dated 6 October 1944 and labeled "Comparison of P-47D, P-47M and P-47N Performance".

http://www.wwiiaircraftperformance.org/p-47/comp-p47dmn.jpg

Here is a page where that data and more from other documents is retyped for easier legibility:

http://www.wwiiaircraftperformance.org/p-47/p-47.html

Because I do not know what altitude you are using as a standard for climbing rate, you will have to look at the document yourself to choose the appropriate climb rates for the D and N models. However, at all altitudes it is clear that the P-47N outclimbs the P-47D.


Regarding the P-51, the site has data for the P-51B model, and shows the climb rate was much better that the anemic rating of 1852 ft/min currently in the scenario database.

Here is a page with various original source data re-typed from documents dated 18 May 1943:

http://www.wwiiaircraftperformance.org/mustang/mustangtest.html

Here is an original graph of climb data:

http://www.wwiiaircraftperformance.org/mustang/p51b-12093-climb.jpg

This original source chart was already shown on the forums:

http://www.wwiiaircraftperformance.org/p-38/fighter-comp-chart.jpg


Recommendations

As I noted above, I cannot give you a specific number because I do not know exactly which climb rate you use in RHS, but certain actions are clear:

1) Reduce climb rate of P-47D.
2) Increase climb rate of P-47N (should be a value even greater than P-47D is now).
3) Increase climb rate of P-51B (possibly to about twice the current value).
4) Reexamine climb rate of P-51D if you have other sources. It almost certainly is much greater than currently in the database (2400 ft/min), presumably greater than the P-51B (after the P-51B is increased).

This material was too late for the current cut, so it will be examined the next time we do an update. Without looking anything up, the problem in general will be that we use source materials which are as comprehensive as possible (so the standards are the same for all planes) - and unless an error was made - this is what the used source said. The problem in particular may be something different:

a) I prefer to use initial ROC, but it is not always in the source. Sometimes I have to use "time to abcd feet" and that is not the same thing.

b) I prefer to use the maximum ROC clean, on a pure interceptor mission. Sometimes I have to use a different value - because the data was not given in that form - and regretfully most references do not tell me what they are using. Amazingly, authorities often mix the standards - probably because they lack comprehensive data for all planes - they give you what they can. Sometimes even a detail reference still has holes in the data, "estimated" data, and things of that sort.

The idea that our data is truly done to a single standard is mythical. We use different sources - although we try very hard to use a single source (Combat Aircraft of World War Two). We also use national references - e.g. Francillon for Japan, Gunston for the USSR, Green for Germany, etc. But for unusual aircraft (see the Wild Catfish or the Martin Mars) we often have to go to specific histories to get anything but a mention of the aircraft. Mixing sources, and using sources which have less than complete data (which in every case happens), means we do not truly have a proper standard. So I am inherantly ready to investigate further any specific case reported to see if we can do better? There are almost 250 types of aircraft - and that is too many to have done deep research on each one (and still be done in time to use it).
We often have found specific data can be better modeled, and we have diligently attempted to get there. This matter, however, is not part of x.761 - and so IF it is changed - it will be in x.762 - which does not at this time have a plan or ETA. It is on the list for review, however.

[witpqs]

I knew it was too late, but if I give it to you it's at least arrow in flight that can land later.

When you have a chance to look over the documents at those links, you'll see that the ROC's in the current database must be wrong according to the standards you just outlined. One possibility is as follows. On that site are documents from the testing done on the P-51B. The documents show two different sets of ROC's. One is with a normal throttle setting, the other at full WEP. Full WEP is what all the ROC's in WITP are based on, as that is the combat standard.

Interestingly, while the WEP ROC's are substantially higher (as mentioned) than the current scenario database, the normal throttle ROC's are actually pretty close to the value in the current scenario database. From this example I'm guessing that some reference books have listed normal throttle ROC for some aircraft, and WEP ROC (what we really want) for others. This makes sense, but it's impossible to know.

[m10bob]

Playing with the editor, aircraft in particular, there is a slot for build rate, and many are marked with a "0". I presume this means it defaults to a pre-determined number, but I'm not sure.
What does it mean if it has a "0" and what if I put a 1 there? Is that "1" per day or is "1" a class/level of how many might be built??

I am having problems with low production of planes like the Lockheed Hudson (A 29) where several nations apparently all draw from the same pool, causing some squadrons to evaporate from lack of pool to draw from.

[Herrbear]

ORIGINAL: m10bob

Playing with the editor, aircraft in particular, there is a slot for build rate, and many are marked with a "0". I presume this means it defaults to a pre-determined number, but I'm not sure.
What does it mean if it has a "0" and what if I put a 1 there? Is that "1" per day or is "1" a class/level of how many might be built??

I am having problems with low production of planes like the Lockheed Hudson (A 29) where several nations apparently all draw from the same pool, causing some squadrons to evaporate from lack of pool to draw from.

Build rate is the number of planes per month that will be built and added to the pool. If the build rate is 1, then 1 plane a month will be built. I am not sure if the build rate continues for that plane until the end of the war or if the plane has an upgrade, then the build rate will continue with the upgrade until the end of the war or when the plane upgrades, it ceases to build any more at all.

[el cid again]

Good answer. The build rate is indeed approximately 1 per month. It is actually a die roll = 1/30 of 1 chance per day - and the actual monthly rate varies statistically. I also may go on forever - but as you speculated - only if the plane does not upgrade. The design intent is that ALLIED OFF MAP production is represented by this value. Allied ON MAP production, and JAPANESE production, are represented at aircraft factories on the map - things subject to supply requirements, bombing, shelling, land combat, etc.

Now the rate should be zero for an aircraft no longer in production, or for a Japanese aircraft. In CHS they set some planes to 1 when they want it to represent machines "assembled from spare parts" - which is very rare - but did happen. Probably the Japanese at Rabaul carried this to the extreme - making entire new aircraft (bombers) out of what they had (zeros) - and using them for long range air strikes - in force (rather than one offs). I do not favor this practice, but throw it out for your consideration.

[m10bob]

Thank you gents...I wonder why the wonderful editor did not come with a detailed "set of instructions" for us mentally challenged folk?[8D]

[el cid again]

Level 6.7611 has been uploaded. The extra 1 is added because four minor eratta were folded in. This should be the last issue for Level 6.

[el cid again]

Your material for the P-47 seems clear:

we have almost the same value for the P-47D - 3120 vice 3160 - and to get things relatively right (one P-47 vs another)
we can use 3160 with no impact to speak of

and the P-47N then becomes 3580 vice our present 2700 - which should be exactly what you had in mind



But your material for the P-51 is a nightmare.
First - it gives us only B model data - so we have no comparison between models.
Second - two sources provided give radically different values - on the order of 1000 feet / minute different!

The more conservative one has many values - from 2420 to 2700 - depending on propeller used - and the median one is 2600 feet per minute.

IF we assume our data for the P-51A and D is right, we can calculate the ROC fairly closely, based on the power plant change.

P-51A data is 2770 feet per minute on 1200 hp.
P-51D data is 3475 feet per minute on 1590 hp.

That would make P-51B about 3102 feet per minute on its 1420 hp. [There is some conflict about the power - some sources give only 1400 hp - and it may depend on the exact engine Mark. There is also some conflict about the weights - but the P-51B is very close to the P-51D - so the ratio compared to P-51A should be pretty close.]

I found a fairly difinitive set of data on the P-51D. It gives a value of 3475 feet / minute - and otherwise almost similar data to other sources - EXCEPT notably the range is given as 2080 miles - more than twice the value of 950 found in other sites. One site gives "1000 miles - 1300 with drop tanks" - so where does 2080 come from? Bigger drop tanks?
Confusing - but not the topic here - which was ROC. Using 3475 for D does give us a significant progression - as we should have. But now what to do about the B????

But the other source says values about 3600 feet per minute - which might be possible (see 3580 for P-47N above) -
but then why do other data differ so greatly?

I am tempted to use the median propeller data of 2600 for the P-51B - which is a lot better than our present 1852 - but still not as good as our present P-51A - nor do I have a clue what P-51D ought to be? This really needs more work.

Increasing the P-47N ROC has the side effect of changing the maneuverability rating. The RHS maneuverability rating is now 37 - significantly better than the 32 we were using. Presumably ROC is used directly in interception calculations - and it is a factor in the maneuverability equation as well.

I found a confirming source at 3475 feet/minute for the P-51D - but it gives max speed as only 448 mph! It indicates that "range with maximum fuel" was 1300 miles AND that is just over 2000 km - so the 2000 figure in another source should have been in km. Starting to make some sense of the P-51D - but not sure what to do about the B model?
Increasing maximum speed slightly to 448, and using the 3475 ROC, we get an RHS maneuverability factor of 36 - an even greater relative increase over the 30 we were using than the late model P-47N got - and oddly to the same value. The maneuverability factor is a composite of four factors - maximum speed - ROC - wing loading & power loading - so quite different aircraft can get similar ratings. This is significantly better than the "wonderful" J7W1 late war Japanese fighter gets - FYI.

P-51B is a bugger. Looks like most sources give max speed 2mph less than we used - at 440 vice 442. But the cruising speed was 362 - significantly better than the 317 we used - and a big deal in code intercept calculations and other routines. That changed endurance downward to 180 minutes (plus 150 more for two 75 gallon drop tanks) - keeping range the same (33/11/8 hexes). But ROC data! I found climb to 10,000 feet in 1 minute and 48 seconds = 5555 feet per minute - awfully high - and higher than the D model - so I am suspicious. D model weighed 400 pounds LESS than the B - but it had more power (1590 hp vice 1420 hp) - so how come it could not climb as well? Different sources = different data. Ugly - as I said. Weal et all claim this lighter, higher powered machine was 3 mph slower than the B model. Wierd.

OK - got it. The technical definition we wish to use is "initial rate of climb" from sea level. It appears that the P-51 increased its ROC after it gained some altitude - I said earlier in the thread "time to altitude" does NOT yield exactly right initial ROC - and this is a case in point.

The data in your higher source was at a weight of 8400 pounds - instead of the 11400 pounds given as Maximum take off rating - and that is going to matter. I am going to use P-51A and P-51D practical data - and the relative change in available power (1200 - 1420 - 1590) - to estimate ROC as 3102 feet per minute. That corresponds to a maneuverability rating of 34 (vice 31 before). This seems to be in the right ball park.

[witpqs]

ORIGINAL: el cid again
I am going to use P-51A and P-51D practical data - and the relative change in available power (1200 - 1420 - 1590) - to estimate ROC as 3102 feet per minute. That corresponds to a maneuverability rating of 34 (vice 31 before). This seems to be in the right ball park.

I follow your entire progression here, and your conclusion makes sense.

BTW, there was another document on that web site regarding a USN test comparison of the P-51H versus the Corsair (I forget which model). They concluded that the Corsair was superior in all respects except ROC when above 25,000 ft (the Corsair ROC was better below 25,000 ft). So, it's quite clear that ROC does vary with altitude.

[m10bob]

ORIGINAL: witpqs

ORIGINAL: el cid again
I am going to use P-51A and P-51D practical data - and the relative change in available power (1200 - 1420 - 1590) - to estimate ROC as 3102 feet per minute. That corresponds to a maneuverability rating of 34 (vice 31 before). This seems to be in the right ball park.

I follow your entire progression here, and your conclusion makes sense.

BTW, there was another document on that web site regarding a USN test comparison of the P-51H versus the Corsair (I forget which model). They concluded that the Corsair was superior in all respects except ROC when above 25,000 ft (the Corsair ROC was better below 25,000 ft). So, it's quite clear that ROC does vary with altitude.

ROC does indeed fluctuate with altitude, depending on several factors, most important being oxygen to the engine capability, octane level of fuel and whether supercharged,etc, and the wingloading of the plane..

BTW, my personal knowledge is only good for prop-driven..I have never flown a stove..

[el cid again]

A courtesy update is issued - this must be installed on top of comprehensive x.76

It only changes a few large CD units so the big guns won't die from lack of starvation

Updates P-47N, P-51B and P-51D data

and corrects a handful of trivial eratta