Best Climb Speed Con't for Nashwan

[Guppy35]

Originally posted by MiloMorai
Dan there is another test with JL165,

Aircraft and Armament Experimental Establishment
Boscombe Down
1 Feb 1944

Spitfire IX JL.165
(Merlin 66)

Trials at +25 lb/sq.inch boost
with Rotol 4 blade propeller

http://www.fourthfightergroup.com/eagles/spit9.html

Saw that after I posted so I deleted that post

Interesting the performance differences between the two LFIX with JL165 being the lesser performer of the two used.

Dan/Slack

[Karnak]

Originally posted by Crumpp
The Spitfire has to directly follow the 190.  At anytime he would be able to abandon the direct chase, hike his nose up, and outclimb the 190 at a steeper angle but slower speed.

The Spitfire should be able to hike his nose up, advance his throttle and outclimb the Fw190 at the same speed.  If the Spitfire has to slow down to exceed the Fw190's climb rate then you would be claiming the Spitfire has a top speed at SL of ~250mph.



Fact: The Spitfire LF.Mk IX has a best climb speed of 170mph.

Fact: The Fw190 has a best climb speed of 182mph.

Fact: The Spitfire LF.MK IX has a significatly better maximum rate of climb than the Fw190 does.

Fact:  The Spitfire LF.Mk IX has a higher rate of climb at 182mph than the Fw190 does.


Are any of these wrong?  Note that I am not talking about following the same vector in any of the statements.

[Crumpp]

Yeah the other one is at (+18) and you have to guess/extrapolate.  Looking at the incease in numbers with SU pump over the regualr (+18), that 30 mph is an average and the increase is not nearly as dramatic at full throttle hieght.

Whatever data you guys want though.  I picked what I thought was the best complete data available.


Crumpp

[Crumpp]

Are any of these wrong? Note that I am not talking about following the same vector in any of the statements.

Your absolutely right Karnack. Those numbers are correct and no one is claiming the Spitfire cannot handily out climb the 190A8 is a sustained climb.

First you have to understand the Power Curve.  The top level speed starts out on the right side of the x axis and moves closer to the origin than the 190's ending near the planes stall speed.  The 190's is higher but does not come as close to the origin (stalls quicker), hence it climbs at a shallower angle.  Both A/C power curves will look the same.  Flat on top with the 190's being higher.

First what is the Power Curve:

http://www.av8n.com/how/htm/energy.html#fig-power-curve-intro


http://www.av8n.com/how/htm/energy.html#fig-power-curve-regimes

Second what does Best Rate of Climb Speed mean:

The dividing line between the mushing regime and the front side of the power curve is the highest point on the power curve.  At this point, the airplane can fly with the minimal amount of dissipation; this is the “low-rent district”. The airspeed where this occurs is called the best-rate-of-climb airspeed and denoted VY.7

The Spitshighest point on the power curve is 170 mph and the highest point on the power curve for the FW-190A8's is 182 mph.

What is the Best Angle of climb and how does it look in relation to the Power curve:

http://www.av8n.com/how/htm/power.html#fig-vx

So what is the Best Rate of Climb?

Where the climb angle (drawn from the origin) meets the green dot.

http://www.av8n.com/how/htm/power.html#fig-vy

You can draw any angle below the 190's Best Climb Rate angle and the Spitfire will be traveling slower on the same vector.

Crumpp

[gripen]

Originally posted by Crumpp
Whatever data you guys want though.  I picked what I thought was the best complete data available.

Well, in fact I don't know if any of the  performance curves for the Fw 190 in the Crumpp's source site are really flight tested.  I get quite contradictory results if I use that data for calculations.

Otherwise I'm pretty much convinced that anykind of rational discussion on the Fw 190 is currently impossible here.

gripen

[Karnak]

Originally posted by Crumpp
You can draw any angle below the 190's Best Climb Rate angle and the Spitfire will be traveling slower on the same vector.

For this to be true, this statement would have to be false:

Fact: The Spitfire LF.Mk IX has a higher rate of climb at 182mph than the Fw190 does.

Yet you just said that it was correct.  If what you are saying is that the Spitfire LF.Mk IX can climb faster than the Fw190 at 182mph by using a steeper climb angle it should follow that if the Spitfire reduces it's climb angle that it now has an excess of power and that power will cause it to fly faster than 182mph.

E.g. the Spitfire can climb above the Fw190 at 182mph or it can go faster than the Fw190 at the same angle of climb.  It may not climb as fast as the Fw190 at that angle, but it will be going faster.

[Angus]

Crumpp,m8, no matter how many links you post, (and actually I confess that you provide very good links), there is no way that you can directly calculate around Newton's law.
Like I said:
"there is no way the Spitties would have been able to trade 12 mph forward movement into 11 mph vertical movement, that's all."

It was perhaps not put up nicely enough in the English language. How I should have put it would be like this: (Sorry for the confusion)

There is no way that a Spitty would need to trade 11 mph of climb for 12 mph of forward movement.
I'll stick with that

[Guppy35]

Originally posted by gripen
Well, in fact I don't know if any of the  performance curves for the Fw 190 in the Crumpp's source site are really flight tested.  I get quite contradictory results if I use that data for calculations.

Otherwise I'm pretty much convinced that anykind of rational discussion on the Fw 190 is currently impossible here.

gripen

Sorry you feel that way gripen.

I think as a Spitfire fan/historian I can safely say that it was the 190 that really pushed the development of the Spit.  The 190 clearly dominated the Spit V and enjoyed a "happy time" to steal a phrase from the U-boats.  

At the same time I think the back and forth development of the Spit and 190 propelled each other with the advent of the Spit IX followed by the VII, XII, VIII, XIV and 21 that all saw service in WW2.  

All of those developments can be linked to the ongoing development of the 190 whether it be the quick introduction of the 'stop gap' Spit IX to even the balance early on, to the introduction of the XII to counter the low level 190 'tip and run' raiders on England's south coast.

Throw in the XIV vs the D9s and I suppose the 21 vs the Ta152 had the war continued.

Both great aircraft that as I've said before engaged in a punch and counterpunch of development throughout the war to keep up with and compete with each other.

Dan/Slack

[Crumpp]

Yet you just said that it was correct. If what you are saying is that the Spitfire LF.Mk IX can climb faster than the Fw190 at 182mph by using a steeper climb angle it should follow that if the Spitfire reduces it's climb angle that it now has an excess of power and that power will cause it to fly faster than 182mph.

Oops,

Led you down the wrong path.  That fact is wrong.  At the top of the curve the spitfire can only go 170mph.  It cannot do 182 at the top.  Now there are portions of the Power curve it can do 182.  On those portions the 190 is also traveling significantly faster than 182mph because it's curve looks about the same, it is just higher.

There is no way that a Spitty would need to trade 11 mph of climb for 12 mph of forward movement.

The forward speed is traveled on the climbing vector, bro.  It's not a measure of velocity straight up.  Newton's Laws are not being violated AND this occurs AFTER the zoom climb in the sustained climb.

Graph it using the instuctions in my last post.  

Crumpp

[hitech]

Don't know how to tell you more specifly but your wrong crump.

Just because it isn't at the max climb rate of the spit, its climb rate is still greater than the the fw's at 182.


HiTech

[Karnak]

Sorry, but the way I see it power curves are irrelevant abstractions.

The fact is that the Spitfire can go 182mph and still climb.  That isn't going to achieve it's maximum climb rate, but so what.  Maximum climb rates don't really play any particular role here.  The fact is that at 182mph the Spitfire LF.Mk IX is climbing at something like 4,500fpm and the Fw190A is climbing at something like 4,000fpm.  Those are sustained numbers at 182mph, not zooms.

In order to achive that rate of climb the Spitfire needs a greater angle of climb.  If it lessens the angle of climb to match the Fw190's angle of climb it will now be able to travel faster than 182mph as the power needed to climb at 4,500fpm at 182mph is more than the power needed to climb at the lower angle and 182mph.

Now, the only way for what you are saying to work is if the Spitfire, when matching the Fw190's angle of climb, climbs at a lower rate than the Fw190 does.

Any other scenario would either have the Spitfire's top speed far lower than it was or allow the Spitfire to directly follow the Fw190's vector.

[Crumpp]

Don't know how to tell you more specifly but your wrong crump.

 This is exactly how Pips Priller used to get away from Spits.  Eric Brown comments this was a hard concept to teach Spit pilots.  Not to directly follow a 190 in the climb.  Crank the nose back and climb at your best angle.  Otherwise the 190 would end up above you.
The Spit cannot climb at 182 mph at the top of the curve.  It can only climb at 170 mph.

And I didn't get the same result at all.  The spit would not be ANYWHERE close to its max climb RATE by directly following the 190.  It will be on the same vector traveling at a slower speed.

It's in black and white on how airplanes fly!

Crumpp

[Crumpp]

Now, the only way for what you are saying to work is if the Spitfire, when matching the Fw190's angle of climb, climbs at a lower rate than the Fw190 does.

That is exactly what he is doing by directly following the 190.  Climbing WELL below his max climb rate on the same vector at a slower speed.

Give me your email and I will send you a graph.

Crumpp

[Nashwan]

That fact is wrong. At the top of the curve the spitfire can only go 170mph. It cannot do 182 at the top. Now there are portions of the Power curve it can do 182. On those portions the 190 is also traveling significantly faster than 182mph because it's curve looks about the same, it is just higher.

Crumpp, I think you've misread the power curve.



The vertical axis here is the climb rate, which we know is higher for the Spit. The power curve for the Spit will be higher than for the 190.

The horizontal axis is the air speed, which we know is slightly higher for the 190.

The Spit curve will be higher, but slightly to the left of the 190s.



You can see that this too shows the Spit can outclimb the 190 at the 190s best climb speed, it's only when the speed gets closer to maximum that the 190 has the higher climb rate.

Note, this isn't meant to indicate anything like exact speeds, it's just a guide to the principles involved.

[Karnak]

email:

aR3M0V3ahola@klassyR3M0V3.com

Take out the "1337" speak and caps.  Sorry for the hassle, just don't want my email addy harvested.


As to what you are saying.  The Spitfire would not be moving slower than the Fw190 at the same climb angle, but lower climb rate.  The Spitfire would be moving faster than the Fw190 is that scenario.  Read my above post.  If the Spitfire has enough power to climb at a steeper angle at 182mph it can go faster than 182mph at the same angle as the Fw190 is at.


EDIT:
Did Priller say what speed he climbed away at?  If not, why do you think it was 182mph and not 275mph or 300mph?