A question for andy but add your opinion too

[Beurling]

Well with  all that stuff you said you did for the air force i figured you could help me with some thing.

I have been flying in the training arena alot lately.

I notice if you have a guy in  a tight fight a dogfight you can cut throttle and just pivit.

I mean the guy is in your front view turning.

Then you just cut throttle and turn and roll till you get on his six. You stay below him and he seem to turn around you. You just follow zero throttle and pivit.

It only struck me the other day is this realistic?

Would a real ww2 fighter be able to do this?

To me this seems wrong at speeds from 150 to 170 with the fight slowly moveing downward.

Is this a flaw with the game?

A fighter say a spit would have to use some throttle?

EYE

[funked]

I just read Robert Johnson's "Thunderbolt" and he says the Germans did this a lot to tighten their turns.  But he said the amount of smoke coming from the exhaust would decrease suddenly so he would know they were doing it.  From his descriptions it sounds like he would usually respond with a High Yo-Yo and wax their asses.  

[flakbait]

Actually you could go with a throttle hop [hi yo-yo only cut power] and nail the bastage. Cutting power would let you dump some speed and probably get around quicker. Depending on your E-state, of course.

------------------------
Flakbait
Delta 6's Flight School
Whattaya mean I can't kill em? Why the hell not?!
 

[Andy Bush]

EYE

Here's a typical WW2 energy chart:

   

If anyone is a little unsure what this thing says...here's a quickie explanation!

The chart is bounded by turn rate in degrees per second (vertical axis) and airspeed in knots (True Airspeed) on the horizontal axis. The chart shows the flight envelope of a P-51 for a given altitude and gross weight. The envelope has three sides...the left is the stall line (max angle of attack), the top is the max G line, and the right side is the max speed line. Curves and lines are included that show turn radius and G points for anywhere inside the envelope.

For this altitude and gross weight, the corner velocity is 185KTAS. That is the best turn the aircraft can instantaneously get for these conditions.

So, if the P-51 slows below 185KTAS and pulls max G, its performance begins to slide down the left side of the envelope. As the G falls below 6, the turn radius remains fairly constant but the turn rate drops off...from about 34 dps at CV to about 17 at 2G.

Because of this (and this is typical of any fighter), it does not really pay to work below 185KTAS. The turn does not 'tighten up' (decreasing radius) and the turn rate drops off quickly...there is no advantage here in this area of the chart to chopping power and continuing to turn...things get worse, not better.

But...if the pilot is above 185KTAS, he can increase his turn performance by throttling back to slow as he applies max G. But...as he nears 185KTAS, he needs to push the power back up.

Note:  WW2 aircraft bled airspeed very rapidly because their power (thrust) to weight ratio was relatively low. A throttle chop was usually done to force an overshoot...not increase turn performance. That's why the P-47 guy talks about yo-yoing off...he's preserving his 3/9 position, not trying to maintain a turn position.

OK. So, is it possible to chop power and 'pivot' underneath an opponent? Yes...under certain conditions (above CV), you might gain a turn rate increase while maintaining a small turn radius. But smart money says slowing down is a risky scheme!

Andy

[This message has been edited by Andy Bush (edited 11-21-2000).]

[funked]

Yep I'm pretty sure Johnson was describing situations where both planes were over CV and the bandit was looking to force an overshoot.

[Beurling]

I guess what i was asking is does ah have it right?

I believe the move i was talking about is wrong. I mean the plane holds e too well.The v and Ix spit.

There was a shift in the last patch to playablity. Its more fun but at zero throttle would it not e bleed faster.

What got me thinking this? A bunch of spit vs spit duels in the TA.

EYE

 

[Badboy]

 

Originally posted by Beurling:
I guess what i was asking is does ah have it right?

I believe the move i was talking about is wrong. I mean the plane holds e too well.The v and Ix spit.

There was a shift in the last patch to playablity. Its more fun but at zero throttle would it not e bleed faster.

What got me thinking this? A bunch of spit vs spit duels in the TA.

EYE

 

I believe AH does have it right.

The changes in the last patch mean that the aircraft generally perform much more realistically now. The additional playability is just a pleasant side effect.
 
Also, cutting throttle when you are already at low speed should be suicide. It might be tempting to ease the throttle back in a scissors, but I won't do it, I prefer to let the speed drop naturally by pulling right to the edge of the envelope. If it looks as though I might concede position, I would rather break out of plane into a rolling scissors than reduce the throttle.
 
Otherwise, the aircraft I've flown so far all seem to behave correctly at low speed.

Badboy

[Beurling]

What about e bleed at zero throttle?

In the spit.

It feels to me like the aw ww1 fighters.

In a fight at zero throtle it seems to hold e forever?

I mean a fight a tight turning fight thats gereraly moveing downward.

Try it out in a fight in the ta. the spit holds e all day.


EYE Btw whels gave me a tip on who you might be flying under.
If he was right its a perfect name
If you see me around say hi. All old aw rivalries are squashed. AH was a new start for more guys here than just me.

[Lephturn]

Beurling, you mention a "tight turning fight generally moving downwar".  Well, if you are doing a descending spiral then it may be useful to cut throttle to stay at your best turning speed.  If you are diving while you do this, you are using the most powerful engine available... gravity.  You may have to cut your engine to keep from exceeding CV.

BTW the diving spiral is a classic move to force the overshoot.  With an enemy on your six you start a hard break into what looks like a horizontal turn.  You then roll it into a diving turn and cut your throttle to maintain your best turning speed.  If the other fellow keeps the power on, he may exceed CV and end up with a larger radius turn and also may overshoot eventually.  When it works right you can often barrel roll out onto his six and wax him.  It's a sucker move though, and if he doesn't go for it he's going to camp out at your six and then blow your bellybutton away.

BTW Beurling, what speed are you going when you cut throttle?  Below 150?  I think the spit has a quite low "corner speed" for maximum sustained turn.  Try that with a FLAT turn and you will see the Spit slow down and lose turning performance as it should.

Although it is not often acknowledged as such due to it's high speed handling problems, the Spit is one of the best energy fighters.  At medium to low speeds the Spit will hold energy as well as, if not better than, any plane in the game.  The Spit driver must be wary not to be forced into an overshoot because the Spit holds E so well.  It can be very difficult to slow that bird down.  Now this is not just true in AH, but was true in the old days of WB as well.  I believe it is realistic that the Spit display these characteristics.  If you folks don't think it's right, the way to prove it is to do some testing.  Numbers is the only way to tell.  You can't examine a flight model from analogies.

BTW, Badboy IS doing these tests, so I recommend you value his input on this issue highly.  

------------------
Lephturn - Chief Trainer
A member of The Flying Pigs  http://www.flyingpigs.com


"My P-47 is a pretty good ship, she took a round coming 'cross the Channel last trip.
Just thinking 'bout my baby and lettin' her rip, always got me through so far."
 - Steve Earl

[Badboy]

 

Originally posted by Beurling:

If you see me around say hi. All old aw rivalries are squashed. AH was a new start for more guys here than just me.

Agreed.

Regarding the Spitfire, I can't find the problem, it looks ok to me. Honestly, the more I test the more impressed I become.

Infact I've had more fun in the last two weeks of AH than in the last two years of AW... It's kinda nice to be at the bottom of the mountain looking up... I have a tough climb ahead, but it's going to be fun fun fun!!

Badboy

[54Ed]

Wow, another great post.

Andy, a few questions on that graph.  First, I note it says KTAS at sea level.  Can I apply those numbers to KIAS at altitude?

Second, do most WWII fighters have a Ps=0 curve that roughly coincides with the 3G line, or is there wide variance?  Any illustrative examples?

Obviously nobody is gonna carry such a graph in the cockpit and use it, but I like to burn a few numbers in my head. I think 185, 3, and 300 are the essential figures to instantly know from that graph.

[Lephturn]

Exactly 54Ed.

What you do is figure out what your best initial turn speed is, your best sustained turn speed, and at what G you can maintain that best turn speed.  With that information you know exactly how fast you want to be at the start of the fight, how slow to go and how hard to pull.  After that it's a matter of figuring out what those numbers are for the other planes that you fight, and trying to put yourself in a position to exploit whatever advantages you may have.

------------------
Lephturn - Chief Trainer
A member of The Flying Pigs  http://www.flyingpigs.com


"My P-47 is a pretty good ship, she took a round coming 'cross the Channel last trip.
Just thinking 'bout my baby and lettin' her rip, always got me through so far."
 - Steve Earl

[Badboy]

Hi 54Ed,

> Andy, a few questions on that graph.
> First, I note it says KTAS at sea level.
> Can I apply those numbers to KIAS at
> altitude?


You can safely assume that the stall speed and corner speed will occur at the same indicated airspeed at all altitudes. That is why indicated airspeed is the more valuable reading, while true airspeed is only required for navigation. While the indicated corner speed will remain the same, the turn rate and radius at that speed will drop quite dramatically as the altitude increases so those values are only good for the one altitude. The interesting points on the sustained turn curve (Ps=0) including the top speed, won’t remain the same because of the way the engine performance varies with altitude.    

> Second, do most WWII fighters have a Ps=0
> curve that roughly coincides with the 3G
> line, or is there wide variance?  Any
> illustrative examples?


For example, a light P51 had a maximum sustained load factor of just over 3.5g at sea level and a relatively high speed. Loaded with fuel and munitions that dropped to 2.3g and if you took that to 20k it could barely sustain a 2g turn. Throw in different aircraft, different configurations and altitudes and you are looking at quite a wide variation. In terms of turn rate and radius variations, the differences can be dramatic. For example, under extreme differences in load outs, the diagram below shows that the AH F4U flying on fumes can match the turn rate of a fully loaded Spitfire, albeit with a slight turn radius disadvantage.

 

> Obviously nobody is gonna carry such a
> graph in the cockpit and use it, but I
> like to burn a few numbers in my head.


These diagrams are best read as an overlay with another aircraft. Rather than remembering discrete points on each curve, I have found it is better to form general impressions about which part of the envelope each aircraft has an advantage, and by how much. Distinctions like more than, or much more than, are close enough because of the potential variations in fuel load etc more accuracy would probably only be of benefit in a duel.

Badboy

[54Ed]

Thanks for the info, badboy. Where did you get those performance graphs?

[Andy Bush]

54Ed

Let's answer those questions...

As a rule TAS and IAS are pretty much equal at low altitudes (near sea level). Then, as altitude increases, TAS tends to be larger than its IAS counterpart...so at 10,000', an IAS of 250 will result in a TAS of some greater value, depending on air temperature.

The result is that if you were to use these graphs, you would tend to be flying a bit faster than the graph intends (if you were to fly at 185mph IAS, you would actually be somewhat faster in mph TAS...as a result, your performance would tend to be slightly less -larger turn radius, fewer degrees in turn rate- than the chart shows).

Second question...about the 0 Ps line. I think the 3G value is pretty representative of WW2 aircraft, particularly the earlier war versions. This represents about a 70 degree bank angle level turn at max power. As the war progressed and power to weight capabilities improved, this value increased slightly. But only slightly. Don't expect any major increases...the F-4 and F-104, for example, could sustain only about 6 G in a level turn and this was for a clean configuration at sea level. I think the WW2 range of Ps values would range from about 2.5G to maybe 4G.

Lastly, you are exactly right regarding rules of thumb. That's what these charts are good for. They give you a ballpark number to remember when it comes to max performance. If the CV is 185, then you can expect max turn performance at that point...when below that speed, you will know that you are giving up speed for nothing, and when above that speed, you are losing the turn rate and radius fight. The 0 Ps value tells you how well you are conserving energy...if you have to pull more than that amount, you know you are going to be losing speed.

Andy