Author Topic: Best Climb Speed Con't for Nashwan (Read 13191 times)

Crumpp · « **Reply #105 on:** August 26, 2004, 01:21:33 PM »

Karnack,

Did you check out the graph I sent you?

HTC is factoring in the MASS of the planes. That is already factored in by the measured performance.

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The poor man, he's completely lost.

No I am not.

I confirmed this with my flight instructor and an F-18 pilot friend of mine.

Crumpp

hitech · « **Reply #106 on:** August 26, 2004, 01:29:14 PM »

Crump: Read your chart, where is the climb rate of the spit above the FW?

HiTech

Nashwan · « **Reply #107 on:** August 26, 2004, 01:32:48 PM »

Crumpp, the vertical axis of the power graph is climb rate, not angle. It's clearly labelled as such:

If you put the Spit and 190 on there together, the power curve of the Spit has to be higher, because the climb rate is higher:

The vertical axis is clearly labelled "Vertical Speed ft/min"

The Spitfire has to be higher on this because it has a higher climb rate. The 190 will be futher to the left because it has higher speed.

Whichever has a hgiher power curve at a particular speed will climb better at that speed.

At high speeds the 190 will outclimb the Spits, but those speeds have to be a lot higher than 200 mph.

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FACT: The top of the Power curve is Flat, therefore it can fly at a wide variety of angles with LITTLE CHANGE to that speed.

No, it can fly at different angles and speed with little change to the rate

Look at the graph. The best angle is where the power curve touches the climb rate line. That's the peak. You can make adjustments to the speed and climb rate, and still climb at very close to that, but when the speed is much different, then the drop in climb rates gets much steeper.

Look at the graph and ignore the "angle" label for a second.

What do you see? You have climb rate on the vertical scale, climb speed on the horizontal. There is a range of climb speeds where you can get close to optimum, then it falls away rapidly.

Crumpp · « **Reply #108 on:** August 26, 2004, 01:33:08 PM »

That is because the spits best climb ANGLE is NOT drawn on the chart!!

Crumpp

justin_g · « **Reply #109 on:** August 26, 2004, 01:38:42 PM »

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In order to outclimb the 190 on the same vector the spitfire would have to be traveling along that vector at a greater rate of speed. It physically cannot due to the fact top of it's curve is lower and the curves look the same.

WHY is the top of the Spitfires power curve lower? The vertical axis on a power curve graph is supposed to be climbrate - so if the Spitfire has a higher maximum climbrate than the Fw 190, the highest point on its curve would be higher than the highest point on the Fw 190 curve.

Nashwan · « **Reply #110 on:** August 26, 2004, 01:42:05 PM »

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That is because the spits best climb ANGLE is NOT drawn on the chart!!

The angle on the chart is just where the maximum rate of climb is achieved.

Look at the difference between your graph and the graph you are basing it on. Yours has the vertical axis as angle, theirs has the vertical axis as climb rate.

Note that even on your graph, the Spit should be higher, because we've established the Spit can climb at a higher angle.

Crumpp · « **Reply #111 on:** August 26, 2004, 01:50:40 PM »

Hold on:

I added in both the best climb angles and best climb rates. I will send it off.

I did not change the axis to "climb rate" However you can do that.

It is NOT intended to be an exact representation of the performance. Just that it is possible to exactly represent the performance.

This just illustrates that whatever angle the Spitfire flys directly following the 190, it will be flying the same vector at slower speed.

Crumpp

Karnak · « **Reply #112 on:** August 26, 2004, 01:59:46 PM »

FYI, I cannot access my home email from work. I will post the new chart you sent when I get home. Should be about 5:30PM PST.

Karnak · « **Reply #113 on:** August 26, 2004, 02:06:34 PM »

Actually, you can try sending it to my work email.

Arizsun.AholaR3M0V3@R3M0V3thewhistlestop.org

Remove the red text.

Crumpp · « **Reply #114 on:** August 26, 2004, 02:16:47 PM »

Cool, thanks Nashwan.

In fact the answer to this in my basic flight manual.

The steeper angle an aircraft flys the more it relys on thrust to weight and less on lift.

That is why the top of the power curve is flat. Because Thrust is tranfers energy to lift to counteract weight. Since energy can niether be created or destroyed their is less energy opposing drag and the plane stays about the same speed for an angle change.

The Spitfire has a great thrust to weight ratio and a high lift wing. That is why it climbs so steep and so slow.

The 190's thrust to weight is not as good. It must rely more on the lift generated by the wing. Hence it HAS to climb at a much faster speed but shallower angle.

http://www.av8n.com/how/htm/4forces.html#fig-four-climb

Simplification guys I know lift thrust and drag all have verticle components.

Crumpp

Crumpp · « **Reply #115 on:** August 26, 2004, 02:20:03 PM »

It's sent off Nashwan

hitech · « **Reply #116 on:** August 26, 2004, 02:35:28 PM »

Crumpp: While your statment of the resone for different best climb speeds in 2 planes is close to correct, (not exatly). It has no bearing what so ever on the discussion at hand. Just because the spit has a slower best climb speed. It in no way inferse that it's climb rate must be slower than the fw at the fw's best climb speed.

All it sais is that the climb rate of the SPIT at the 182 must be less than it would be 170. It does not meen that it would be less than the FW's.

HiTech

Crumpp · « **Reply #117 on:** August 26, 2004, 02:50:54 PM »

Hitech,

If the Spit is traveling the SAME vector as the 190 but at a lower speed then it will not catch the 190.

If the spit is climbing at a higher rate but slower speed then it is not following the same vector and therefore not on the 190's tail.

Crumpp

Crumpp · « **Reply #118 on:** August 26, 2004, 02:52:37 PM »

Then what you are saying Hitech is that Best Climb Speed is NOT the top of the power curve and the PhD/Flight instructor has it all wrong.

Crumpp

Karnak · « **Reply #119 on:** August 26, 2004, 02:53:13 PM »

Crump's Second Chart: