Speed won't reach 1000Km/h

[nadvgia 2]

Hello,

 

I was trying to mod the Yak-25 Flashlight A regarding it's speed that it only reached 850 Kms per hour. My objective is that it reaches 1015 Kms/h as max. speed.

 

The original YAK-25_DATA FlightControl:

StallSpeed=51.68
CruiseSpeed=182.57
ClimbSpeed=173.96
CornerSpeed=89.51
MaxG=4.66
MaxSpeedSL=222.22
MachLimit=0.85
PitchDamper=0.8
RollDamper=0.6
YawDamper=0.2
GunBoresightAngle=-2

 

 

Now what i´ve tried to change so far with maybe excessive values but without sucess also in the FlightControl:

StallSpeed=51.68
//CruiseSpeed=182.57
CruiseSpeed=500.0
//ClimbSpeed=173.96
ClimbSpeed=500.0
CornerSpeed=89.51
MaxG=4.66
//MaxSpeedSL=222.22
MaxSpeedSL=500.0
//MachLimit=0.85
MachLimit=0.95
PitchDamper=0.8
RollDamper=0.6
YawDamper=0.2
GunBoresightAngle=-2

 

 

 

Only 987 Km/h is what it allows.

 

Is there anywhere in the Data file or maybe other file that i should change some values?

 

Best Regards

 

[+Gunrunner 313]

Welcome aboard and sorry that I'll have to be a smart ass for your first post but...

You do realize that the real thing probably never reached that speed at sea level, right ?

Most aircrafts top speed, unless otherwise stated, are given "at altitude", never at sea level by default.

 

I would suggest getting back to the stock ini and trying, let's say, around 15000/20000ft which is probably the altitude for the documented top speed.

Lower is unlikely and would mean a far higher top speed speed at altitude.

Higher is also unlikely as, starting at 30000ft it would make it supersonic, which the Yak-25 was definitely not in level flight.

 

As a rule of thumb for planes of that era, at low altitude you reach lower speeds than at medium altitude due to atmospheric density (meaning higher drag, in part due to far from perfect aerodynamics), at high altitude you reach lower speeds than at medium altitude due to underperforming engines in a less dense atmosphere.

Also keep in mind that the higher the altitude, the lower in km/h the Mach number.

At sea level in a standard atmosphere, Mach 1 is about 1225km/h.

At 20,000ft, it's about 1138km/h.

At 30,000ft, it's about 1090km/h.

From 40,000ft and, for all practical purposes, above, it's about 1060km/h.

 

So, did 850km/h at sea level for a Yak-25 sound right ? Yeah, definitely...

Does 1000+km/h at sea level seem entirely unrealistic ? Definitely.

[Toryu 156]

 

//MaxSpeedSL=222.22

MaxSpeedSL=500.0

 

The speed there is in m/s and 500m/s is a little bit....excessive (that would be Mach 1.48).

 

Also, consider what Gunrunner says.

In a subsonic design (means: Mach limited), maximal true airspeed is attained at crossover-altitude, which usually is somewhere between FL230 to FL280 (depending on the actual figures).

[Caesar 305]

Something else to bear in mind is that the numbers you're seeing at the bottom left of the screen reflect indicated airspeed, vice true airspeed.  So, not only are you not going to hit the advertized maximum speed at sea level, but if you get to higher altitudes, those numbers are probably going to read lower than expected until the game swaps from IAS to Mach numbers.  See this discussion:  http://combatace.com/topic/85255-change-aircraft-speed/?hl=airspeed&do=findComment&comment=685772

[nadvgia 2]

Thanks for the replies, that's some info i didn't know regarding speed :) I´ve placed the stock ini file again to try again with higher ceiling but it went down to the original speed.

 

stock - ceiling=13900

 

modded - celling=23900

 

But if it changed in anyway, yeah wouldn't be realistic.