Spitfire

[EagleDNY]

Originally posted by Widewing

There's nothing wrong with the Spitfire Mk.XVI's flight model, especially with regard to speed, climb and acceleration.

My regards,

Widewing

I wish someone would explain the turn performance to me though.  I've run the Gonzo charts on all the Spit variants (including the Seafire), and they just seem "odd".

The Spit XVI and VIII turn almost identically, despite the clipped wings on the XVI.  The Seafire, which used to turn almost identical circles with the Spit V, now turns more like a Spit IX.  The Spit V has the best turning performance of all the cannon-armed Spits, but the Spit IX (which was a V with an improved engine) has the worst turning performance.  

I'd just like to have some real data so that I know what I'm flying (or fighting).  First thing I'd like to know is what wing each Mk we have is using - I assume the Spit XVI is a clipped "E" wing because of the armament.  Are all the others "C" wing models, or are the ones without 250lb bomb racks actually "B" wing models?  Which Merlin engine is supposedly in each model?  

I'm with Krusty a bit on this - I've seen some odd things done in a Spit XVI, and I too have been caught from behind in a 109K4 wondering "how the heck he could have caught me at that speed" after pulling out from a dive.  I'm not saying definitely that something is screwy with the flight modeling, but I'd like to see some testing done and posted.

EagleDNY
$.02

[Bronk]

Originally posted by EagleDNY


I'm with Krusty a bit on this - I've seen some odd things done in a Spit XVI, and I too have been caught from behind in a 109K4 wondering "how the heck he could have caught me at that speed" after pulling out from a dive.  I'm not saying definitely that something is screwy with the flight modeling, but I'd like to see some testing done and posted.

EagleDNY
$.02

This is why you need film. You have no idea what that spit's E state was.
I don't want to hear "he just lifted.".  One thing I like to do is go to a capped base shallow dive in get lots of smash , run in low along my base and hope a vulcher is foolish enough to follow. Or foolish enough to think he is going to out zoom me.

So film or it's "bullflop".


Bronk

[mussie]

E can be a strange thing

I did not think it was possible but I hit 600mph in a TA152 the otherday.... It was only for a second and I had to be REAL careful pulling out of the dive (she was creaking like hell) but I made it out in one peice.

Surely a Spitty with a big enough dive could get pretty dam fast....

[Kev367th]

Originally posted by EagleDNY
I wish someone would explain the turn performance to me though.  I've run the Gonzo charts on all the Spit variants (including the Seafire), and they just seem "odd".

The Spit XVI and VIII turn almost identically, despite the clipped wings on the XVI.  The Seafire, which used to turn almost identical circles with the Spit V, now turns more like a Spit IX.  The Spit V has the best turning performance of all the cannon-armed Spits, but the Spit IX (which was a V with an improved engine) has the worst turning performance.  

I'd just like to have some real data so that I know what I'm flying (or fighting).  First thing I'd like to know is what wing each Mk we have is using - I assume the Spit XVI is a clipped "E" wing because of the armament.  Are all the others "C" wing models, or are the ones without 250lb bomb racks actually "B" wing models?  Which Merlin engine is supposedly in each model?  

I'm with Krusty a bit on this - I've seen some odd things done in a Spit XVI, and I too have been caught from behind in a 109K4 wondering "how the heck he could have caught me at that speed" after pulling out from a dive.  I'm not saying definitely that something is screwy with the flight modeling, but I'd like to see some testing done and posted.

EagleDNY
$.02

First easy part - XVI's had an improved stiffer spar, and other refinements to the wing that made it generally less flexible than the 'c' wing. Thats why the clipped XVI can turn with the VIII.

[edit] Just remembered - It was also suggested in a thread a long time ago that some of the Mk VIII's F.E. had incorrectly been based on an VIII with extended tips, but no idea what came of the discussion.

Wings - Engines by service date (roughly)
I - 'a' wing  - Merlin III?
V - 'b' wing - Merlin 46
IX - unversal wing - Merlin 61
Seafire IIc - 'c' wing - Merlin 46 (not sure where the data came from for this one, but appears to a mix of a Seafire Ib and IIc)
VIII - universal wing - Merlin 66
XIV - 'e' wing - Griffon 65
XVI - clipped 'e' wing - Merlin 266 (U.S. Made Merlin 66) NB: Ours is actually based on a Merlin 66

Wish they'd fix the XIV and give it climb it actually had!!!!

Should also point out that there have been various debates about Spit IX wings regarding 'c' wings, universal wings, and what some call the improved universal wing.

Also that contrary to what kit manufacturers would have you believe a IXc never existed, only the IX and IXe.
To further complicate things pilots themselves would often refer to Merlin 61 Spit IX's as IXa's, and Merlin 66 Spit IX's as IXb's.

[BaldEagl]

Originally posted by mussie
E can be a strange thing

I did not think it was possible but I hit 600mph in a TA152 the otherday.... It was only for a second and I had to be REAL careful pulling out of the dive (she was creaking like hell) but I made it out in one peice.

Surely a Spitty with a big enough dive could get pretty dam fast....

In another Spit related thread one day someone was trying to tell me they could make me rip the wings off a Spit XVI.  I argued that I'd black out first and never have the opportunity to rip them off (I never had in a XVI even though I've pushed well past the point of creaking and shuddering).

Well, a week or so later I was chasing a fast bogie from alt, I think it was a 190.  The nose wanted to lift, the airframe was creaking and the plane began to shudder but I was gaining ground and kept the peddle to the metal chasing this guy down.  I don't know what speed i was actually going but it had to be well over 500 IAS.

Then I noticed the guy was diving to his field ack and, not wanting to become ack bait I decided I better pull out.  I barely touched the yoke and immediately both wings snapped off.

I was flying with a squad mate in another XVI who stayed up top.  He couldn't believe it.

Proved me wrong.  Funny thing about E and yes, you can get a XVI cooking in a dive.

[Krusty]

You don't have to be in a high-powered dive to rip spit wings off. I've done it at 300 or so just by pulling too hard on the stick. It's very annoying.

[Lusche]

Originally posted by Krusty
You don't have to be in a high-powered dive to rip spit wings off. I've done it at 300 or so just by pulling too hard on the stick. It's very annoying.

Only if you are damaged before or maybe continously overstressed your plane. I have yet to lose a wing by any other means than bullets or trees. I even tried to shed my wings at speeds 300-350mph, without success.

[Krusty]

It might have been that they were stressed, but I've done it without taking hits (and sometimes after taking hits). It's common enough that I always throttle back when I start creaking, and I ease up on my stick pulling when I creak. I'd rather blow my position than rip my wings off, eh?

[BaldEagl]

Originally posted by Krusty
You don't have to be in a high-powered dive to rip spit wings off. I've done it at 300 or so just by pulling too hard on the stick. It's very annoying.

Like I said, I've pushed well past the point of airfrme tolerence many times and never ripped the wings off a Spit (although it was common in AW), which was why I argued the point so adamantly in that other thread.

The day that I did they didn't actually rip, they snapped off at the wing roots as soon as they caught a little air.

I can't believe they would come off at 300.  If you pull too hard at 300 you will simply black out.

[Widewing]

Originally posted by EagleDNY
I wish someone would explain the turn performance to me though.  I've run the Gonzo charts on all the Spit variants (including the Seafire), and they just seem "odd".

The Spit XVI and VIII turn almost identically, despite the clipped wings on the XVI.  The Seafire, which used to turn almost identical circles with the Spit V, now turns more like a Spit IX.  The Spit V has the best turning performance of all the cannon-armed Spits, but the Spit IX (which was a V with an improved engine) has the worst turning performance.  

I'd just like to have some real data so that I know what I'm flying (or fighting).  First thing I'd like to know is what wing each Mk we have is using - I assume the Spit XVI is a clipped "E" wing because of the armament.  Are all the others "C" wing models, or are the ones without 250lb bomb racks actually "B" wing models?  Which Merlin engine is supposedly in each model?  

I'm with Krusty a bit on this - I've seen some odd things done in a Spit XVI, and I too have been caught from behind in a 109K4 wondering "how the heck he could have caught me at that speed" after pulling out from a dive.  I'm not saying definitely that something is screwy with the flight modeling, but I'd like to see some testing done and posted.

EagleDNY
$.02

Turning radius as posted on DokGonzo's page are based upon the testing of one pilot. I sometimes generate a smaller turn radius testing the same aircraft. Sometimes a bit larger. One can fly too deep into a stall buffet, which actually increases the radius while reducing the turn rate. To get a more accurate collection of data, more testing needs to done by different pilots, with the best repeatable data being used.  

When I test them, I find the SpitVIII turns a smaller radius than the SpitXVI by about 24 feet. Not much, but enough. It's also more stable at the limit, which I find to be of greater value than the minor turn radius advantage. You push the SpitVIII a bit harder than the SpitXVI.

The Seafire has had it's flight model adjusted to reflect the correct weight (it is 13% heavier than the SpitV). Thus, it doesn't turn like a SpitV.

I find that SpitIX turns as well as the SpitVIII, but in a sustained circle contest the SpitVIII's greater power can be decisive.

My regards,

Widewing

[Kweassa]

DkGonzo's site, using Mosq's turn radius datas lists the Spitfire numbers as follows;

* Spit8: 568ft normal, 448ft flaps
* Spit9: 632ft normal, 433ft flaps
* Spit16: 567ft normal, 450ft flaps
* Spit14: 629ft normal, 509ft flaps

 The data above seems a bit erratic, in that the relationships of the planes' turn radius is something like  " (Spit8 = Spit16) < (Spit14 = Spit9) ". Logically, the Spit8 and the Spit9 should be near identical, since the Spit8 is essentially a Spit LF9. The Spit16 should have a somewhat larger radius than both the Spit8 and the Spit9, with the Spit14 coming in last.
 

 Now, compare above numbers with my own test numbers below. This is in no way an attempt to defile Mosq's efforts, but rather a presentation of a 2nd opinion. My turn radius testings uses a purely mechanical method which takes away as much human skill factor as possible.

* Spit8: 560ft normal, 466ft flaps
* Spit9: 571ft normal, 460ft flaps
* Spit16: 599ft normal, 443ft flaps
* Spit14: 666ft normal, 546ft flaps

 The numbers are more or less as expected with this version of test results.

[Benny Moore]

I'm not saying that the numbers on that site are correct or incorrect, but a few things to remember are that those numbers measure sustained turning circle, and do not account for turn time.  Of course, usually larger engine means a wider circle but a faster turn, so that still doesn't explain the Spitfire's crazy turns on that site.  I'd expect the heavier Spitfires, because of their improved engines, to have the widest turns but best acceleration and climb and also the best turn times (which that site doesn't list).  With that in mind, I'd be more inclined to believe that Kweassa's numbers are more correct.  Kweassa, how did you measure the turn circles' diameter?

[Kweassa]

Radius.

 My figures can be defined as;

 "tighest sustained turn possible on highest throttle setting at constant speed"

[Widewing]

Originally posted by Benny Moore
I'm not saying that the numbers on that site are correct or incorrect, but a few things to remember are that those numbers measure sustained turning circle, and do not account for turn time.  Of course, usually larger engine means a wider circle but a faster turn, so that still doesn't explain the Spitfire's crazy turns on that site.  I'd expect the heavier Spitfires, because of their improved engines, to have the widest turns but best acceleration and climb and also the best turn times (which that site doesn't list).  With that in mind, I'd be more inclined to believe that Kweassa's numbers are more correct.  Kweassa, how did you measure the turn circles' diameter?

Those numbers do factor in turning time. Time is a key variable in the equation. You need to know speed and time to calculate turn radius.

If I fly three continuous circles and it requires 50 seconds at an average speed of 120 mph, I can determine the average turn radius.

120 / 60 = miles per minute, or 2.0

2.0 X 5280 = feet per minute or 10,560

10560 / 60 = Feet per second or 176

176 x 50 =  total distance traveled or 8800 feet

8800 / 3 = circumference of average circle or 2933.33 feet

2933.33 / Pi (3.14) = diameter of circle or 934.18 feet

934.12 / 2 = radius of circle or 467.09 feet.

With a stop watch, calculator and proper technique, anyone can measure their turn radius. Proper technique is the most important factor. This requires a disciplined scientific approach or the data will reflect only the skill limits of the pilot and not the limits of the aircraft.

Kweessa uses the same equation, but I recall that he uses stall limiter, which takes the pilot out of the equation. However, this limits how hard the plane can be pushed. You can always turn a smaller circle with stall limiter off. His circles will be bigger, but he will not have pilot induced anomalies. Thus, the relationship between the aircraft is maintained, if not exactly reflective of their absolute performance.

My regards,

Widewing

[Benny Moore]

I've just spent about twenty minutes thinking about that and poking at Calculator.  I'm no good with mathematics, so help me understand.  It is impossible for an aircraft to traverse the same circle as another aircraft in a shorter period of time?  No, that can't be right.  So how do you know if one ship completed the circle slower than ... no, that doesn't make sense.  Let me try again.  I've always thought that a ship that has a wider turn, by completing that turn faster, could out-turn another airplane which has a tighter turn.  But your calculations seem to say that this is impossible.  How can you calculate which aircraft will complete the same turn quicker ... argh, my head hurts.  I'll get back to you on this.

Okay, I've figured it out, I think.  Taking your hypothetical fighter which can complete a sustained turn in 17 seconds at a speed of 120 M.P.H. with a diameter of 952 feet, I did the same calculations only at a speed of 145 M.P.H.  This fighter only took 14 seconds to make the same 952 foot diameter circle.  They both completed the same circle, but the second fighter did it three seconds earlier and therefore out-turned the first one.  The problem with the charts the list only turn radius or diameter is that they do not specify speeds and times.  As I just calculated, two aircraft with identical turn radii can have different turn times.