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Vx and Vr for ROF aircraft?


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#1 Arfsix

Arfsix
  • Posts: 199
  • LocationGalveston, Texas USA

Posted 28 November 2015 - 01:54

     In the topic: se5 help neede, http://riseofflight.com/forum/topic/47080-se5-help-neede/page-2#entry651565, FourSpeed stated -

 

     Yep. Basically, look at Winged-Warrior's approach (in this thread), as he (and a few others) use the SE5a to great effect with BnZ tactics.

Simplified - the basic steps are:

      6> Climb away at Vx (Best Angle of Climb) if: you killed him OR you want to maximize height (for an immediate second bounce) without getting too much horizontal separation

     6b> Climb away at Vy (Best Rate of Climb) if: he's alive enough to try to prop-hang you and you need to extend both height and horizontal distance.

 

     The question is, what are the actual indicated airspeeds (as read on the airspeed indicator in the cockpit) for Vx and Vr for each aircraft in Rise of Flight? I am looking for numbers I can use for Vx and Vr in the simulation, not necessarily the historically correct figures. 

 

Thanks!


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The heavens were the grandstands and only the gods were spectators. The stake was the world, the forfeit was the player's place at the table, and the game had no recess. It was the most dangerous of all sports and the most fascinating. It got in the blood like wine. It aged men forty years in forty days. It ruined nervous systems in an hour. -- Elliott White Springs, 13 Victories


#2 piecost

piecost
  • Posts: 1318

Posted 28 November 2015 - 16:55

Arfsix,

 

An.Petrovich, the FM developer posted a curve of climb rate for the SE5a over a graph of historic data. see:

 

http://riseofflight....ew-fixes/page-3

post #111

 

So, for that aircraft best rate of climb speed is 75 MPH (IAS). The best angle of climb speed can be deduced from the graph and should be less than 75 MPH.

 

I don't know about other aircraft. Others have performed tests on time to height or climb rate should have an idea.


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#3 FourSpeed

FourSpeed
  • Posts: 1757

Posted 28 November 2015 - 20:48

Hi ArfSix,

 

First, a small (nitpicky, I suppose  ;)) correction.  Vr  is the Speed at Rotation (ie. the point at which you ease the stick back to takeoff), so it, while useful to know, doesn't impact this topic.

 

I don't know if anyone has put together a V-speed chart for the various planes, akin to SeaW0lf's excellent climb and speed charts. Obviously, each plane will have slightly different values for Vx and Vy.

 

Certainly, temperature, pressure, aircraft design, and other factors, can have definite effects on those numbers, but a relatively easy, ballpark, "close enough for government work", approach for most light aircraft is to calculate it based on stall speed.

 

That will probably suffice here.

 

Vx is usually about  1.2 or 1.3 times the Stall Speed.

Vy is usually about  1.5 or 1.6 times the Stall Speed.

 

So, if the aircraft has a stalling speed of 50 mph, then ballpark figures for Vx would be 60-65 mph and Vy would be somewhere around 75-80 mph.

 

 

Regards,

:icon_e_salute:

 

 

 

PS> My 1985 Cessna 152 POH lists these speeds as  43, 55, 67 (kts)  for instance, so those multipliers are  1.28  and  1.56  respectively...


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#4 Arfsix

Arfsix
  • Posts: 199
  • LocationGalveston, Texas USA

Posted 28 November 2015 - 22:21

Hi ArfSix,

 

First, a small (nitpicky, I suppose  ;)) correction.  Vr  is the Speed at Rotation (ie. the point at which you ease the stick back to takeoff), so it, while useful to know, doesn't impact this topic.

 

 

Thanks for the reply and I did mean to say Vy. I was hoping that someone might actually have run the figures.

 

The primary reason I was asking is that I have been unable to keep formation with AI aircraft in any of the single player missions. If I match the rate of climb they outrun me in speed and if I match airspeed, they climb away from me.


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The heavens were the grandstands and only the gods were spectators. The stake was the world, the forfeit was the player's place at the table, and the game had no recess. It was the most dangerous of all sports and the most fascinating. It got in the blood like wine. It aged men forty years in forty days. It ruined nervous systems in an hour. -- Elliott White Springs, 13 Victories


#5 piecost

piecost
  • Posts: 1318

Posted 30 November 2015 - 18:23

Fourspeed, that is a really useful rule of thumb. It works well for the best climb speed of the SE5a.

 

I attach a datasheet containing the stall speeds of most RoF planes.The factors can be combined with this for an approximate guide.

 

Regarding formation flying; I read recently that it tends to reduce the speed by around 15%This is for a 2-ship formation. I wonder if it changes with more planes. Does the RoF AI formation leader reduce throttle to allow other flight members to keep up?

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