Aces High Bulletin Board

General Forums => Aircraft and Vehicles => Topic started by: AKHog on January 18, 2010, 05:45:27 PM

Title: .speed questions
Post by: AKHog on January 18, 2010, 05:45:27 PM
Sorry if this is the wrong forum or has been talked about before. I tried the search but apparently the '.' part of .speed gets left off, so the results are too much to sort through.

I'm wondering what the default .speed is, and what is it based on? Is it a best climb speed, and if so is it Vx or Vy?
Title: Re: .speed questions
Post by: MachFly on January 18, 2010, 06:56:44 PM
I believe it's just 160 for all fighter and 120 for all bombers or something like that.
Title: Re: .speed questions
Post by: TequilaChaser on January 19, 2010, 01:19:05 AM
I believe it's just 160 for all fighter and 120 for all bombers or something like that.

hmmm I always thought it was the best climb speed / rate for each individual aircraft type....... whether it is a fighter or a bomber .......

hitting ALt X will show you what the default   climbspeed is for each individual aircraft you fly, AKHog 

can anyone concur?
Title: Re: .speed questions
Post by: Ghosth on January 19, 2010, 06:38:36 AM
TC is correct, it is set to that airplanes best default climb speed.

In bombers can range from 130 up, Fighters most often in the 140 - 170 range.
Title: Re: .speed questions
Post by: colmbo on January 19, 2010, 01:45:44 PM
If I set a different .speed for a particular aircraft will it default back to the default speed or does it stay where I set it?
Title: Re: .speed questions
Post by: Chalenge on January 19, 2010, 02:47:25 PM
It resets after you end flight. Also with combat trim OFF its a good idea to set climb speed for corner speed before you start a fight and then manually trim after that.
Title: Re: .speed questions
Post by: TequilaChaser on January 19, 2010, 03:26:40 PM
It resets after you end flight. Also with combat trim OFF its a good idea to set climb speed for corner speed before you start a fight and then manually trim after that.

could you expand on this further please, Sir?  I have never heard this before...... I am curious
Title: Re: .speed questions
Post by: stran on January 19, 2010, 04:06:37 PM
It resets after you end flight. Also with combat trim OFF its a good idea to set climb speed for corner speed before you start a fight and then manually trim after that.

it doesn't matter what speed you start using manual trim as long as you are trim. are you saying you always enter a fight at that specific speed?
Title: Re: .speed questions
Post by: colmbo on January 19, 2010, 04:18:53 PM
It resets after you end flight. Also with combat trim OFF its a good idea to set climb speed for corner speed before you start a fight and then manually trim after that.

I fail to see how setting .speed is going to effect anything...unless you left out letting your airplane attain that speed so that it is trimmed for that speed.
Title: Re: .speed questions
Post by: Chalenge on January 19, 2010, 05:39:26 PM
Okay I wasnt clear I guess. Set the speed for corner speed for your plane let the plane accelerate to that speed and then hit alt-x and let the plane settle to that speed before you get to combat. This is more handy in the faster planes than it is in a Brew for instance.
Title: Re: .speed questions
Post by: AKHog on January 19, 2010, 11:27:06 PM
TC is correct, it is set to that airplanes best default climb speed.

Best? Best rate, or best angle?
Title: Re: .speed questions
Post by: stran on January 19, 2010, 11:50:50 PM
Best? Best rate, or best angle?
those two go hand in hand.
Title: Re: .speed questions
Post by: colmbo on January 20, 2010, 01:06:23 AM
those two go hand in hand.

Not in R/L.  Best angle (Vx) will be a lower airspeed than best rate(Vy).  The Best rate airspeed will decrease with altitude (around 2 mph/thousand feet) until Vx and Vy meet.
Title: Re: .speed questions
Post by: stran on January 20, 2010, 03:07:15 AM
.
Title: Re: .speed questions
Post by: AKHog on January 20, 2010, 07:26:41 AM
those two go hand in hand.

No, they don't.
Title: Re: .speed questions
Post by: mtnman on January 20, 2010, 12:03:20 PM
hmmm I always thought it was the best climb speed / rate for each individual aircraft type....... whether it is a fighter or a bomber .......

hitting ALt X will show you what the default   climbspeed is for each individual aircraft you fly, AKHog  

can anyone concur?

It does vary a bit, but each aircraft type seems to "share" a preset auto-speed.  All the F4U's are preset to 154.  The Jugs are set to 159(?) P51's at 175 (as well as the P38's).  Auto-speed pays attention to indicated speeds, not actual.

I always understood the preset speed to be set at the (approximate) speed that gives the plane the best climb rate.  The actual rate of climb will change with altitude and load-out though.  The actual angle of climb/descent will also change over time as this setting is used.  As you climb higher, you'll climb at a slightly/slowly reducing angle to allow the plane to maintain the .speed set by you or by default.  If you climb high enough with the default auto-speed you "should" actually end up in level flight.

There was a thread about gliding distance (long ago), and it was shown that the best glide speed (for max distance) was the preset/default auto-speed as well.

There are a few strategic "tricks" that go along with this setting.  As Chalenge mentioned, some set it for best corner speed (I'm not sure how effective that one is).  It works nice for bombers if you set it at a higher speed than you can climb, but slow enough to not rip your wings off.  That way you can "auto-dive" at say 300mph, while you're in the tail guns.  This has a nice effect of causing many fighters to loiter behind your tail for a nice shot.  Just make sure you keep an eye on the ground....

I'll use .speed 300/350 occasionally in my F4U, but don't find a ton of use for adjusting this from default (in my own flying).

As for the "reset" question- if you adjust your auto-speed speed, it will reset back to default when you end sortie.  This setting isn't "remembered" by the game the way .sortie and .salvo settings are...
Title: Re: .speed questions
Post by: Stoney on January 20, 2010, 12:25:31 PM
In-game, default alt-x is an approximate Vy for all aircraft.
Title: Re: .speed questions
Post by: AKHog on January 20, 2010, 03:38:25 PM
There was a thread about gliding distance (long ago), and it was shown that the best glide speed (for max distance) was the preset/default auto-speed as well.

Thats probably because max L/D is closely related to Vy. I believe if you don't account for prop efficiency then they are essentially the same.

The main reason I posted this thread is I wanted to see if all aircraft were set at default for Vy. (And I didn't want to take the time to test each one).

So far nobody has given me anything solid. Stoney says its "approximate Vy", I'm not sure what that means.

If they are not set at Vy, then finding it could make a [small] difference when you are climbing out to intercept.
Title: Re: .speed questions
Post by: Stoney on January 20, 2010, 03:47:22 PM
There was a thread about gliding distance (long ago), and it was shown that the best glide speed (for max distance) was the preset/default auto-speed as well.

I did some testing with the P-47M at typical MA weights and found that the best glide speed was a good bit higher than alt-x speed.  Now, for a SWAG, alt-x is close enough that it won't make a huge difference over short distances, but there was a difference.

Best glide in the Jug was about 175-180 IAS with the prop feathered.

http://bbs.hitechcreations.com/smf/index.php/topic,276974.0.html

Title: Re: .speed questions
Post by: Stoney on January 20, 2010, 03:50:21 PM
So far nobody has given me anything solid. Stoney says its "approximate Vy", I'm not sure what that means.

Because Vy changes depending on altitude.  In your Cessna 172 that doesn't make it above 10,000 feet regularly, a single value gets you pretty close.  But for a plane that has a critical altitude of 34,000 feet, the speed will change.  The 160 that AH2 has as the default is a compromise, that gets you relatively close to Vy.  The book values are similar, but different--within +/- 5mph...