Best Climb Speed Con't for Nashwan

[Crumpp]

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


Check how throttle changes effect the curve.

[Karnak]

What it boils down to is that you're demanding to much of a degradation in the Spitfire's performance over too narrow a band of the performance spectrum.

[hitech]

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

Figure 1.13: Power curve/speed/climb rate

Note Y axis is climb rate, is how it should be labled on yours.

Then look at your spit and fw's max climb rates per your chart.

[MiloMorai]

Crumpp your theory is all very well and good but how about some hard numbers for speed,  at various RoCs for the Spit IX.

[YUCCA]

atm they aren't aruguing the legitimacy of the numbers.  They're just argueing about the labeling of it hehe.  

geek fight!

[niknak]

I should preface this by saying I have little aero engineering experience (but i do have a physics degree).


Could the problem be solved by finding the aircrafts "effective power" at a given angle? If we assume that the 2 aircrafts drag coeffs are equal enough to not worry about them at lowish speeds (under 300 mph) we can find how the total power output of the 2 aircraft become equal at a certain angle if we factor in mass (i.e. we are just  worrying about power and weight).

i.e.  Force output by engine - mg sin theta


theta = angle of climb.

if we say F(spit) - m(spit)g sin theta = F(spit) - m(spit)g sin theta

Unkown is theta (and is the same for both sides)

This should be a rough  and ready calculation for above what angle the spit will be able to match trajectories and hunt down FW.

If it were to be above the angle at which the FW has its maximum climb rate crumpp has some ammunition. However i suspect it will be at a shallower angle where both aircraft would have a speed, as suggested before, of around 250mph.

On the other hand it might give you garbage

[Crumpp]

I see how your saying it adjusts Hitech.

Due to the shape of the power curve:
I do think that at the front side of the power curve their will be a zone the 190 can climb faster on the same vector.  Definately if it has a level speed advantage.  Maybe at the same speed and probably not if the Spitfire has a level speed advantage.  This certainly will not hold true up to Best Climb angle.

Crumpp

[Crumpp]

Looking at this again:

For the Merlin 61 that we have in AH it definately holds true.  If the merlin 61 directly follows an FW-190 in the climb it will be left behind.

At higher altitudes were the climbing discrepancy is not as pronounced it's not so definate.

And of course any altitude the 190 has a level speed advantage it also holds true but at much shallower angles.

Crumpp

[Bombjack]

That's ok Karnack. I teach some pretty difficult concepts to grasp at work.

Please don't take my inability to get this point across an indication of my teaching ability!

I see people all the time who can "parrot". There products will look exactly like the examples provided but in reality they have no understanding of the underlying concepts. Somebody throwing co-efficients around to me, in aerodyamics, is a clear statement of their inability to grasp what they really mean.

Was I the only one who found this hilarious?

[hitech]

Crumpp: The spit could stay with the fw, unitill some were above the 260 mph range.


The problem with your chart is the chart is simply incorect. See below for the basic problem.



Here is justin_g excess power chart. It is more representive of the real performance of poth planes.





On aside note a plane can fly in a steady state as long as it is under the power curve line.

It just needs to reduce throttle.


The other item you can read from these charts is acceleration. Until the spit read line crosses the Fw line, it will out accelerate the fw.

HiTech

[Crumpp]

Even with the Merlin 61 (+16) there will be large portions of the curve the FW-190 can climb at and get away.


With the (+12) the Spitfire will be left behind.

So according to that chart, Below 10 the FW 190 can leave the spit.

Correct?

BTW almost done with the calcs for the "other" thread.

Crumpp

[hitech]

No not Below 10.

It could get away if above 280 MPH per the 2nd chart.


HiTech

[Crumpp]

Ahh,

Thanks.  So there is a critical speed you must maintain.

Crumpp

[hitech]

Now your getting it.

[Karnak]

HiTech's chart is very much like I imagined it would look.