Speed & Climb Rate Graphs

[Zipper730]

It's amazing how the charts and graphs from nation to nation and even within different branches of a nation vary: The US Navy for example generally have pretty well written charts, often easy to read and things of that sort; the US Army Air Force on the other hand has some quality issues, some of them are damned near illegible.

I'm curious if anybody has ever transcribed the graphed data for speed across the altitude range (engine power, true airspeed with position error corrections), and climb-rate (engine power, true airspeed with position-error correction) up to the service ceiling and stuff like that into graphs that are of high quality and easily legible.

 

[GregP]

As far as I know, there are no sources that "collect" these data in one place. Anyone who did would have very good material for a book that could be profitable if it turned out to be mostly correct. Part of the problem is most US and British sources have data every 5,000 feet and most German, Soviet, and Japanese data you can find are at units of 1,000 meters, so there are no charts that speficy the data at the same altitudes and units as the other side.

To collect the data, you'd need one set in English units and one in metric, and the the speed and climb charts where the supercharger has to change speeds will all need to be done manually and they don't follow a smooth curve. They would need piecewise equations for the segments taht follow a function line. I's estimate maybe 4 equations for a 2-speed supercharger, with boundary conditions specified to assure no chart discontinuities.

It's certainly doable, but will take a lot of work!

If I did it, it would very certainly not be supplied as a "freebie!" But I'd advertise that it was available, for sure, in printed form only. Once you release an electronic copy, you'll see almost no more sales! I know too many people who have had that happen to them.

 

[tomo pauk]

Jeff (Corsning) has the data, posted mosty on this forum. The speed and climb rate is listed per each full kilometre, starting with sea level. Tabulating the data into a spreadsheet should not be the problem, apart from the time used, and spreadsheet programs can derive graphs from that.
Engine power at range of altitudes is a bit of problem, since the power graphs do not involve ram effect, while aircraft flying at speed invoke the ram effect. Nothing big of a problem, but care should be taken.

 

[Zipper730]

As far as I know, there are no sources that "collect" these data in one place.

I'm thinking that would be a really cool idea. I'd be quite interested in such a project.

There's gotta be some good that could come out of it.

Anyone who did would have very good material for a book that could be profitable if it turned out to be mostly correct.

Could be useful for flight-sim games

Part of the problem is most US and British sources have data every 5,000 feet and most German, Soviet, and Japanese data you can find are at units of 1,000 meters, so there are no charts that specify the data at the same altitudes and units as the other side.

That's a good point, however there's gotta be some way to estimate these things

• Pilot reports & accounts
• Estimation of horsepower to speed (if I recall there was a cubic relationship from horsepower to speed or vice-versa), and aircraft critical altitudes are usually specified which covers ram compression
• I know how to convert feet to meters and kilograms to pounds and liters to gallons and imperial gallons to gallons and all that, tedious as it is, I can do it.

To collect the data, you'd need one set in English units and one in metric, and the the speed and climb charts where the supercharger has to change speeds will all need to be done manually and they don't follow a smooth curve.

I'm not an expert at graphing curves.

They would need piecewise equations for the segments taht follow a function line.

At the penalty of sounding stupid (math was not my strong suit): What is a piecewise equation, and a function line?

If I did it, it would very certainly not be supplied as a "freebie!"

Now if I did it, it'd be a freebie: I'm not in it for money, I'm an aviation buff and in it for providing helpful information for other aviation buffs

 

[Zipper730]

Jeff (Corsning) has the data, posted mosty on this forum. The speed and climb rate is listed per each full kilometre, starting with sea level. Tabulating the data into a spreadsheet should not be the problem, apart from the time used, and spreadsheet programs can derive graphs from that.

I'll see what I find on his stuff

Engine power at range of altitudes is a bit of problem, since the power graphs do not involve ram effect

Wait, the P-51's listed critical altitude was around 24000' and in practice was 29800' -- that seems like a ram listing?

 

[CORSNING]

I'll see what I find on his stuff

Zipper, save your time. All the information I previously posted was lost when Warbirdsforum.com
went defunct about a year or so ago. I have all the information on hard copy, just not sure where
to post it...again.

Wait, the P-51's listed critical altitude was around 24000' and in practice was 29800' -- that seems like a ram listing?

From the altitudes you have posted, it is easy to see that you are talking about the Merlin powered
versions. The V-1650-3 (early versions) were tested to have a full throttle altitude (high blower) of
27,400-29800 ft. depending on boost applied. The V-1650-7 (latter P-51Bs and all Ds) full throttle
altitude (high blower) was 20,600-24,200 ft. depending on boost.

 

[fubar57]

I don't know how much stuff is saved here...Wayback Machine

 

[CORSNING]

Now to address the publish for money or post on line for everyone, .... hum?
I really could use a few extra bucks right now, but I chose the latter. However
If anyone would like to contribute to the I Need More Ammunition Fund please
divide your donations and send half to wwiiaircraftperformance,org. I always had
the will and the drive to put something together but Mike Williams' and Neil Stirling's
site gave me incentive to get it started.

 

[CORSNING]

George,
That is amazing man. Even though most of what I posted is no longer there, a
lot still is. How do you come up with all this stuff and still find time to make all
those great models?

 

[fubar57]

7 day weekends help a lot Jeff

 

[CORSNING]

I have not stayed idle. I am still researching, updating and adding to
my original files for future posting. GregP once told me I needed
to purchase Excel, and he is correct. I have even gone shopping to
price it (about $150 here). You know, I was going to do just that a
few weeks ago but then I found out that there was a gun show near
where I live............

I still do not have Excel......BUT, I was able to get a Springfield,
Ruger and Bersa.

 

[Zipper730]

From the altitudes you have posted, it is easy to see that you are talking about the Merlin powered
versions.

Yes, I did derive my figures from the V-1650-3

 

[MiTasol]

GregP once told me I needed to purchase Excel

and you can still get several Excel clones for free like OpenOffice and LibreOffice. THere is a learning curve but no more than if you miss one excel upgrade so win win, top toys and a spreadsheet program in the same week

 

[Zipper730]

Uh, this might sound stupid... the link no longer exists. I can't even access it on the Wayback Machine, so C CORSNING , what kind of climb-data do you have available for at this moment? Do you have the P-61's?

 

[Zipper730]

I've gotten some data which I've compiled on better sources (Excel): Makes it greatly easier, as you can enter a formula and fill-handle it down the rest of the way so you don't have to enter it over and over again. You also learn how to remember important things like what's a row and a column (something I routinely used to mix-up).

I should start posting soon (today or tomorrow based on fatigue), files might very well be zipped because of the fact that they might be in excess of the forum's guidelines.

 

[CORSNING]

Zipper,
I just now saw your last two posts. Been pretty busy with the
holidays and research. I am still working on cleaning up my files
so that I can better compare Japanese vs. Russian fighters. The
A6M2m21's actual combat performance has me stuck right now.
I haven't gotten all the performance worked out for the P-61A
just yet, but I do have graphs for climb, speed, range and roll rate.
I am also trying to work in learning to graph on excel/Google Sheets
or the like. I have previously worked out about 150-200 different
WW2 fighters in chart form (not the P-61 yet).
I just need to find the time to make it all happen ( I still work full
time).

Jeff

 

[Zipper730]

Here's the compiled data, this covers the Hurricane data from WWII Aircraft Performance. It's clearly a preliminary because I don't have horsepower listed, and there was a part of me that was curious as to the tip velocity of propeller aircraft (surprisingly high): Things that are in gray bold generally are figures that are estimated, so they're may not be accurate.

I also sometimes have under speed trials two speeds for 0' altitude, which is about measuring tip-speed versus speed.

 

[Zipper730]

Zipper,
I just now saw your last two posts. Been pretty busy with the
holidays and research. I am still working on cleaning up my files
so that I can better compare Japanese vs. Russian fighters. The
A6M2m21's actual combat performance has me stuck right now.
I haven't gotten all the performance worked out for the P-61A
just yet, but I do have graphs for climb, speed, range and roll rate.
I am also trying to work in learning to graph on excel/Google Sheets
or the like. I have previously worked out about 150-200 different
WW2 fighters in chart form (not the P-61 yet).
I just need to find the time to make it all happen ( I still work full
time).

Jeff

I still appreciate the effort.

 

[Zipper730]

As far as I know, there are no sources that "collect" these data in one place. Anyone who did would have very good material for a book that could be profitable if it turned out to be mostly correct.

That's right.

Part of the problem is most US and British sources have data every 5,000 feet

Actually the British usually listed altitude like this...

1. All of them
   • S/L
   • 1000'
   • 2000'
   • 3000'
   • 5000'
   • 6500'
   • 10000'
   • 13000'
   • 15000'
   • 16500'
   • 18000'
   • 20000'
   • 23000'
   • 26000'
   • 28000'
   • 30000'
2. Early (above 30000')
   • 32000'
   • 34000'
   • 35000'
3. Later (above 30000')
   • 33000'
   • 35000'

With critical altitude listed either in the chart, or at the bottom of the chart (I've went through just a few of these graphs, lol). The USAAC, worked in increments of 5000 feet, with the USN generally just listing key altitudes (I've read a few of those too).

most German, Soviet, and Japanese data you can find are at units of 1,000 meters, so there are no charts that speficy the data at the same altitudes and units as the other side

Converting meters to feet isn't that hard to do. Just multiply by 3.280839895 (technically it's a repeating number, it goes out to 42 places, then repeats again and again and again -- I know, I have way too much time on my hands -- but 3.280839895 is usually good enough).

the speed and climb charts where the supercharger has to change speeds will all need to be done manually and they don't follow a smooth curve.

This is actually a valid point. You would probably require a couple of equations to ensure that you get accurate figures across the whole chart.

It's certainly doable, but will take a lot of work . . . .If I did it, it would very certainly not be supplied as a "freebie!" But I'd advertise that it was available, for sure, in printed form only.

Yes, but since you'd probably be selling (by intent or not) to a sizable chunk of this forum's membership, I'd hope you'd keep the price within a nominal amount (particularly with some kind of member discount ) -- preferably below $50, and no more than $100 US.

 

[wuzak]

Converting meters to feet isn't that hard to do. Just multiply by 3.280839895 (technically it's a repeating number, it goes out to 42 places, then repeats again and again and again -- I know, I have way too much time on my hands -- but 3.280839895 is usually good enough).

Why wouldn't you just divide by 0.3048?

Since the foot is defined as 0.3048 metres.