Acceleration comparisons

[pandacat]

It's quite interesting to see post-510kph, 2700rpm actually accelerates faster than 3000rpm for p51c. Btw, do you have similar data on P51Ds? 5nt and 20na. I would expect slightly worse performance. Also, it's surprising to see 109G series has slower acceleration than mustangs given 109 has higher power to mass ratio.

[MaxGunz]

Consider how CSP's work in the case of the P-51.

[pandacat]

Originally Posted by MaxGunz

Consider how CSP's work in the case of the P-51.

But doesn't everybody else have CSP, too? Spit, 109, 190? Or P51's CSP is somewhat special? For spit and 109, it seems from the charts that 3000rpm always accelerates faster than 2700rpm

[MaxGunz]

At what speed and altitude? Compare the whole Ps graphs.

Consider the drag as size and coefficient, P-51 is bigger.

Where is the supercharger working best compared to the alt?

The speed of the plane has much to do with the optimal blade angle but mostly...

When you command more prop rpm than the plane has power to support, the prop will flatten a bit and you'll lose some thrust.

Most IL2 planes have some form of pilot-controlled CSP and some are even more automated though there are pre and early war models that don't have CSP all the way down to fixed props.

[horseback]

Originally Posted by pandacat

But doesn't everybody else have CSP, too? Spit, 109, 190? Or P51's CSP is somewhat special? For spit and 109, it seems from the charts that 3000rpm always accelerates faster than 2700rpm

Mustang's throttle is supposed to control manifold pressure directly, rather than just the amount of fuel going to the engine,as in other types. During the 10k tests, I ran the Spit IX LF at 2700 and 3000 rpm to see if there was a difference, and 3000 rpm was always superior at all speeds.

The Mustang is a bit different. If you look at the 10k charts, there is a point at which the Mustang at 2700 rpm will accelerate more quickly than at 3000rpm, and it reaches top speed much sooner after the three or so earlier 10 kph intervals. In the thicker air at 100 meters, this doesn't seem to happen, or at least it isn't as obvious.

Currently building my 5k database, which will probably show a transitional difference somewhat less than the 10k tests for the Mustang at 2700 vs 3000rpm; it will probably be more pronounced at 15k and 25k.

cheers

horseback

[MaxGunz]

Would you need to do as much trim change in a constant TAS climb as you do in a constant height drag race? You'd probably use trim just to adjust IAS as needed every few 100 to 1000 ft.
Climb rate = Ps analog at 1 speed and many alts.

P-51 can climb at speeds the SpitIX can only be losing alt to maintain. Throw that in with the percentage statistics, performance has scale as well as percentages.

[FC99]

First of all, it is always appreciated and respected when somebody "do the walk".

Now the bad part.

1. This kind of tests is best done with the utility written for such purpose.
You can find it here.
http://lesnihu.wz.cz/autopilot/autopilot.html
It is easy to set it up and it will execute script which will control the plane instead of you. It is much easier to test planes that way and what is even more important this is way more precise and repeatable test method.

2. Flying the plane is just half of the job, second part is logging the flight parameters. You can do it your way but there is a better and easier way. Use UDPGraph, you can get various parameters on the screen and in the file.
Download it here:
http://avcpage.achilikin.com/il2dl/graph_en.htm

Once you get these two utilities working you will be able to watch TV while your PC is doing the work for you and as a bonus you will get much better results.

[Woke Up Dead]

There's still merit in doing it "by hand" though, Horseback made a lot of useful observations about the difficulty of trimming some planes as they accelerate. I am curious about how much difference trim makes though, maybe someone familiar with that tool could set up a similar test for a couple of the planes that Horseback thought were hard to trim to see how much better the results are.

[horseback]

Originally Posted by FC99

First of all, it is always appreciated and respected when somebody "do the walk".

Now the bad part.

1. This kind of tests is best done with the utility written for such purpose.
You can find it here.
http://lesnihu.wz.cz/autopilot/autopilot.html
It is easy to set it up and it will execute script which will control the plane instead of you. It is much easier to test planes that way and what is even more important this is way more precise and repeatable test method.

2. Flying the plane is just half of the job, second part is logging the flight parameters. You can do it your way but there is a better and easier way. Use UDPGraph, you can get various parameters on the screen and in the file.
Download it here:
http://avcpage.achilikin.com/il2dl/graph_en.htm

Once you get these two utilities working you will be able to watch TV while your PC is doing the work for you and as a bonus you will get much better results.

The whole point of this exercise is to do it by hand; if the average player cannot duplicate the results of the tests without a ton of specialized controllers, or be able to overcome some of the problems inherent in flying a given aircraft without many, many hours of practice, meeting the 'book' numbers is meaningless.

This highlights some of the reasons that the ai so consistently outperform human players in certain aircraft and why some aircraft that should have many more users based on their historical records are less successful with occasional users.

cheers

horseback