Speed vs Angle

[GhostCDB]

Earlier today Midway was on 200 asked: Why does it seem faster to fly level at 100ft to target and zoom climb to 10k than to auto climb to target and reach 10k.

I am not sure if he can read the forums or if he doesn't have access at all, but it sparked a conversation on 200.

Here is my "attempt" at answering the questions, I am sure there are some better answers out there so if you have it please feel free to comment.

To my understanding, I may be completely wrong, there are airspeeds related to the optimum rate of climbing and they are Vx and Vy. Vx is the airspeed for the best angle of climb and Vy is the airspeed for the best rate of climb with Vx being slower than Vy.

If you climb at Vy it allows you to maximize your altitude gained per minute (time). It enables you to maximize your climb while giving up the least amount of time.  

If you climb at Vx it allows you to maximize your altitude gained per kilometer or distance covered. Vx it allows you to maximize your climb while giving up little ground distance and this happens at the speed for the difference between where the thrust (Manifold Pressure) and drag are greatest.

Vx increases with your altitude and Vy decreases with altitude. Vx=Vy at maximum altitude. Which is what 38k in-game, although icepac has "reached" 40k+


http://www.langleyflyingschool.com/Pages/CPGS%204%20Aerodynamics%20and%20Theory%20of%20Flight%20Part%201.html#Drag

I often use that website for school purposes, has a lot of good information available.

Does the game model air density?

Air Density affects lift.

Want more sense out of it, try this site: http://www.grc.nasa.gov/WWW/k-12/airplane/density.html

[Skyyr]

Probably because the time it takes to accelerate to the 400kts or so needed to zoom climb to 10k is overlooked.

If you're at sea level, doing 400kts or so, and you zoom climb, yes, you'll make it to 10k faster than if you climbed at Vy. However, from a dead start, or starting at Vy, you'd find that it was faster to climb using Vy. It would take several minutes to accelerate to the airspeed required to do a pure zoom climb to a 10k target altitude... and even then it might still fall short.

Also, keep in mind that zoom climbs are only useful if you can control the aircraft upon reaching your target altitude. So zooming to 10k, only to have your airspeed at 55kts, isn't going to do much good as you're going to stall and have to nose-down, losing altitude, to regain enough airspeed for control. So zooming to 10k in and of itself is relatively worthless, you need to be able to zoom climb and then recover before MCA, or minimum controllable airspeed.

The usefulness of Vy becomes apparent once the above is realized.

[FLS]

It's faster to climb first because the lighter air density lets you fly faster. If the target is very close it may be faster on the deck but the farther the target the more benefit from climbing first. You also have more energy to use at the target when you come in at altitude.

[GhostCDB]

It's faster to climb first because the lighter air density lets you fly faster. If the target is very close it may be faster on the deck but the farther the target the more benefit from climbing first. You also have more energy to use at the target when you come in at altitude.

So Air Density is modeled in-game? I know drag is from searching up threads on "Drag Model".
If air density isn't modeled then everything you have suggested is a theory, yes?

[Cthulhu]

So Air Density is modeled in-game? I know drag is from searching up threads on "Drag Model".
If air density isn't modeled then everything you have suggested is a theory, yes?

Of course density is modeled, either directly, or indirectly via simplified equations for CL-alpha, CD-alpha, etc. vs altitude.

Keep in mind also that engine performance is greatly affected by air density. SL engine performance, as well as the greater lift due to denser air, has a huge impact on SL climb rate.

[FLOOB]

What plane can ballistic climb 10k?

[Cthulhu]

What plane can ballistic climb 10k?

What are you referring to as a ballistic climb? A powerless climb?

[Zoney]

So Air Density is modeled in-game? I know drag is from searching up threads on "Drag Model".
If air density isn't modeled then everything you have suggested is a theory, yes?

   Are you suggesting that air density is not ?

[Cthulhu]

  Are you suggesting that air density is not ?

I want density modeled into my C_L-alpha curves, but totally omitted from my C_D-alpha curves.   

[FLS]

So Air Density is modeled in-game? I know drag is from searching up threads on "Drag Model".
If air density isn't modeled then everything you have suggested is a theory, yes?

Next time you're playing check your airspeed gauge. The needle shows IAS and there is a mark showing TAS. Note the increasing difference between IAS and TAS as you gain altitude. Aces High uses std air pressure and adjusts for altitude. The gauges show you the results of air density on lift, drag, and thrust.

[Cthulhu]

Next time you're playing check your airspeed gauge. The needle shows IAS and there is a mark showing TAS. Note the increasing difference between IAS and TAS as you gain altitude. Aces High uses std air pressure and adjusts for altitude. The gauges show you the results of air density on lift, drag, and thrust.

Yep. This is the reason your TAS can be 400 kts at altitude, yet your plane can stall so easily. Your IAS, the effective airspeed over the wing and control surfaces, is significantly less at altitude.

[Zoney]

I want density modeled into my C_L-alpha curves, but totally omitted from my C_D-alpha curves.   

OK Mr. Smartypants 

[GhostCDB]

What plane can ballistic climb 10k?

This is all hypothetically speaking, but I believe the Yak3 can and LA7 and of course the 163.

[Cthulhu]

OK Mr. Smartypants 

 

[pembquist]

No, the truth is that the Yak 3 is lighter than air. (And annoying as well.)