PDA

View Full Version : Historical Spitfire test - rollrate NACA L334



Abbuzze
03-08-2006, 06:54 AM
Here is a page out of a NACA Spitfire test (L334).

Very interesting read, but also very long 51 pages with charts. It gives a very nice overview about the advantages and the shortcomings of this very good fighter.
The tested Version was a Spitfire V with metal ailerons.

Max. 40lb could be applied to the stick by the pilot in a roll, so maybe the higher values are calculated or some aid was used.

The roll rate is given in RAD. 1RAD is 57.295 degree. So you can calculate deg/sec

No explanation is needed for the line with "Maximum deflection". To read this chart took a force- 30lb for example, take the IAS speed, this time 225mph, and the 1.0 rad line is right there, so the Spitfire rolled with 57deg/sec to the right.
If no line with 0.8 - 1.0 - 1.2 rad are directly hitting, you have to interpolate this values.

So maximum rollrate to the right with 40lb at 300mph IAS is around 63deg/sec. (maybe 2 more or less)

So if someone wants to compare the real world Spit V to our one - Lets go! I have no time to do it. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Enjoy it.

http://mitglied.lycos.de/p123/bilder/rollrate_spitv.jpg

Complete test, download it, if you want to read the complete 51pages.
http://mitglied.lycos.de/luftwaffe1/aircraft/raf/spit_flying.pdf

Abbuzze
03-08-2006, 06:54 AM
Here is a page out of a NACA Spitfire test (L334).

Very interesting read, but also very long 51 pages with charts. It gives a very nice overview about the advantages and the shortcomings of this very good fighter.
The tested Version was a Spitfire V with metal ailerons.

Max. 40lb could be applied to the stick by the pilot in a roll, so maybe the higher values are calculated or some aid was used.

The roll rate is given in RAD. 1RAD is 57.295 degree. So you can calculate deg/sec

No explanation is needed for the line with "Maximum deflection". To read this chart took a force- 30lb for example, take the IAS speed, this time 225mph, and the 1.0 rad line is right there, so the Spitfire rolled with 57deg/sec to the right.
If no line with 0.8 - 1.0 - 1.2 rad are directly hitting, you have to interpolate this values.

So maximum rollrate to the right with 40lb at 300mph IAS is around 63deg/sec. (maybe 2 more or less)

So if someone wants to compare the real world Spit V to our one - Lets go! I have no time to do it. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Enjoy it.

http://mitglied.lycos.de/p123/bilder/rollrate_spitv.jpg

Complete test, download it, if you want to read the complete 51pages.
http://mitglied.lycos.de/luftwaffe1/aircraft/raf/spit_flying.pdf

ImpStarDuece
03-08-2006, 07:02 AM
http://img451.imageshack.us/img451/7199/fw190rollrate015in.jpg

RAF comparison of Spitfire V, FW 190, Mustang I and Typhoon from 1943.

Points of interest:

1. Spit peak roll rate:

105 deg/sec for normal wings
150 deg/sec for clipped wings

2. FW 190 peak roll rate

161 deg/sec at 250 mph IAS

3. Typhoon rolled SLOW

4. Mustang rolled better than the FW 190 above 350 mph IAS

ImpStarDuece
03-08-2006, 07:06 AM
NACA 868, with the red line indicating Tempest V roll rate from RAF flight trials.

http://img140.imageshack.us/img140/2643/nacawithtempest5ke.jpg

Abbuzze
03-08-2006, 07:23 AM
Yes, the peak is a very interesting point!

It shows the speed where the pilot is not able anymore to apply full aileron. The figures you mentiond are close to the one from L334.
For this non clipped wing spit they say 110 mph, but the altitude was lower.

The low peak of the Spitfire show that this plane had a large aileron deflection, resulting a good roll rate and light forces at low speed.

US Planes had usually a lower max. deflection. Resulting a lower roll rate at low and sometimes even mid speed, but a much better one at high speed, because max. deflection could be hold at much higher speeds.

The shape of the ailerons are not as important as the mechanical layout. This was shown in other test with P36 and P40. They have similar shape, but much different max. deflection. P36 behave much more like the Spit with a strong peak, outrolling the P40 at low speed, while the P40 is much better at high speed.

ImpStarDuece
03-08-2006, 07:36 AM
The other test was against a Spitfire I and a Hurricane I, both with fabric covered alierons.

http://img324.imageshack.us/img324/2443/7151094126808rollratespithurri.jpg

Peak roll for Spitfire I with fabric covered alierons was 65 degrees a second at 30lbs stick force.


RAAF test of Spitfire V with metal alierons at 30lbs shows a peak roll rate of 78 degrees a second.
http://img529.imageshack.us/img529/7743/rolldata30sz.jpg

As IL-2 models peak stick deflection at 50lbs, regardless of plane type, Spitfire rate of roll should be taken as similar to NACA 868, as it is measuered at this value.

anarchy52
03-08-2006, 07:42 AM
Typhoon had poor roll rate indeed. At peak roll rate it needs 6.5 seconds to complete the roll. High speed roll equal to Zero and turn rate of Focke-Wulf. Add a low critical mach number and engine with serious teething problems, and it's no wonder it was kicked out of the fighter role http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Pierre Closterman felt that he barely escaped death on his first flight in the Typhoon.

Tempest was generaly an improvment except in turn rate which was inferior to Typhoon (due to wing profile, Typhoon actually had higher wingloading) but the main characteristics of both planes was ment to be speed and powerful weapons.

PapaFly
03-08-2006, 09:15 AM
Hmmm, so according to the graph, we 190 drivers should have a huge rolling advantage over the normal-wing spit at 250mph.

190 should roll 70degs more than the spit!!!

Do you see this modeled in the sim?

faustnik
03-08-2006, 09:30 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by PapaFly:
Hmmm, so according to the graph, we 190 drivers should have a huge rolling advantage over the normal-wing spit at 250mph.

190 should roll 70degs more than the spit!!!

Do you see this modeled in the sim? </div></BLOCKQUOTE>

Yeah, at higher speeds the Spit really falls of in roll in the sim. The difference between the Fw190 and Spit roll might not be as great as some historical data, but, it is there.

TX-Zen
03-08-2006, 09:39 AM
Very cool information, thanks!

Makes me want to go do some roll testing now.



Faust, can you use your impressive graphaholic skills to make an easier to read chart?


I don't see as well as I used to because of all the years I've been looking down the 190's gunsight.

http://forums.ubi.com/images/smilies/53.gif

faustnik
03-08-2006, 09:43 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TX-Zen:

Faust, can you use your impressive graphaholic skills to make an easier to read chart?
</div></BLOCKQUOTE>

Which chart Zen?

faustnik
03-08-2006, 10:39 AM
Of course you are assuming that the captured Fw190 tested by the RAF was not "sloppy" and had properly aligned aelerons, and that's a BIG assumption.

The main problem I see in the sim is the lack of roll advantage in switching to the clipped Spit.


EDIT: Whoa! what heppened Buzzsaw? Or am I seeing things???? http://forums.ubi.com/images/smilies/354.gif http://forums.ubi.com/images/smilies/88.gif

Buzzsaw-
03-08-2006, 10:43 AM
Salute

Couple comments:

The NACA test which Abuzze first refers to is not representative of a properly maintained Spitfire V with metal ailerons.

The test aircraft was the only Spitfire V in the U.S. at the time, and before NACA got it, it had been extensively flown by all the U.S. military organizations.

A well known RAF pilot, Robert Stanford Tuck, was in the U.S. at the time on a publicity tour, and he had the opportunity to fly it, prior to NACA getting it for their tests, and he reported it as being very slack in the controls, and unresponsive, when compared to a properly maintained Spitfire V.

The other charts shown are much more representative of what a Spitfire with metal ailerons could accomplish.

Buzzsaw-
03-08-2006, 10:48 AM
Salute

More details from a RAF rollrate comparison 190A vs Spitfires:

http://img363.imageshack.us/img363/9484/1fff4effectofclippingspitfirew.jpg
http://img363.imageshack.us/img363/2792/20a1bpilotopinions2vy.jpg
http://img363.imageshack.us/img363/7074/6e2bbclippedwingconclusions3hz.jpg

Buzzsaw-
03-08-2006, 10:53 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by faustnik:
Of course you are assuming that the captured Fw190 tested by the RAF was not "sloppy" and had properly aligned aelerons, and that's a BIG assumption. </div></BLOCKQUOTE>

We don't know that, true, we can only assume that RAF techicians at the AFDU and RAE, who were notable for their overall high expertise, and extensive experience with foreign aircraft, especially German ones, DID adjust the ailerons correctly.

What we DO know for sure, is that the Spit V as tested by NACA was NOT adjusted correctly. And that is reflected in the results which are much poorer than normally reported in RAF tests.

P.S. I edited my note because I realized someone else had already posted the chart I was including.

faustnik
03-08-2006, 11:01 AM
I like the pilot answers on the comparison chart you posted Buzzsaw. You can hear the sarcasm when you read the "hardly" of pilot 3. http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

Buzzsaw-
03-08-2006, 11:10 AM
Salute Faustnik

The problem is inertial effects. I do not believe the Sim models them correctly. (also for dive and zoom climb but that is another issue)

In these RAF tests, the Spitfire pilots are trying to follow a 190 which initially starts rolling one way, then reverses it, and rolls the opposite direction.

Inertial effects in cases where a pilot reverses roll direction cause a very large delay in the response of certain aircraft, especially those with larger wing areas, or wide wingspans, or pointed wingtips, or ailerons placed away from the wingtips, such as the Spitfire, or more especially, the P-38. Planes like the 190, with small wing area, shorter wingspans, squared off wingtips and ailerons placed right at the wingtip suffer much less delay in reversing direction.

If the game modelled inertia properly, then we would see the advantage going to the 190's.

As it stands now, there is almost zero hesitation in reversing a roll direction.

You should look over the NACA examination of what makes for an effective rollrate in aircraft design, the famous Report 868:

http://naca.larc.nasa.gov/reports/1947/naca-report-868/

faustnik
03-08-2006, 11:14 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Buzzsaw-:


You should look over the NACA examination of what makes for an effective rollrate in aircraft design, the famous Report 868:

http://naca.larc.nasa.gov/reports/1947/naca-report-868/ </div></BLOCKQUOTE>

I'll print it out and read it. Thanks!

*********

Yeah, I think previous patches had more intertia effects, which were great. Made all the a/c feel much more substantial, as if they really had weight.

Abbuzze
03-08-2006, 11:41 AM
Buzz, did he real meant this plane, or did he just spoke about the ailerons?
And how do you know that this plane didn´t got some maintance before the test?

Even if this part is not related to the ailerons, does 3/4 inch of stick movement for the elevator to the first sign of stall sounds slack? All over this Spit don´t sound very sluggish.

Elevator:
http://mitglied.lycos.de/p123/bilder/spitfire_elevator%20text.jpg


Ailerons: if you like, klick it.
http://mitglied.lycos.de/p123/bilder/spitfire%20ailerons%20text.jpg
http://mitglied.lycos.de/p123/bilder/spitfire%20ailerons%20text2.jpg

robban75
03-08-2006, 12:58 PM
Is there only one Fw 190 roll rate test? Are there others?

Sintubin
03-08-2006, 01:00 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by PapaFly:
Hmmm, so according to the graph, we 190 drivers should have a huge rolling advantage over the normal-wing spit at 250mph.

190 should roll 70degs more than the spit!!!

Do you see this modeled in the sim? </div></BLOCKQUOTE>

Nope


never was !! in this sim

Buzzsaw-
03-08-2006, 01:16 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Abbuzze:
Buzz, did he real meant this plane, or did he just spoke about the ailerons?
And how do you know that this plane didn´t got some maintance before the test?

Even if this part is not related to the ailerons, does 3/4 inch of stick movement for the elevator to the first sign of stall sounds slack? All over this Spit don´t sound very sluggish. </div></BLOCKQUOTE>

The extremely effective elevator was a characteristic of all early Spitfires, up to and including the earlier V's, mostly the VA. Compared to U.S. aircraft, elevator response was very noticeable. This would be observed even if the controls were out of adjustment. This was not the case with ailerons, which had a more normal response than the elevator even when properly trimmed. This disharmony of controls was changed with the later models of the V when the elevator was rebalanced. I suspect this V was an A model which had upgraded ailerons, as opposed to originally being equipped with metal versions. That is likely why its elevator exhibited the characteristics you mention.

All you have to do is to look at the other three charts posted on this thread to see the large difference in rollrate between the NACA tested metal aileron equipped Spitfire and the RAF tested ones.

There are other charts out there, which also show the rollrate of the metal aileron Spitfire, and they again confirm the results obtained in the RAF tests. The NACA test was an anomaly and not representative of the real potential of the aircraft.

Kurfurst__
03-08-2006, 02:19 PM
Does anyone has the details of this tested(?) Mk V (IF it's a test, and not some calculation based on rule of thumb about the general effect of decreasing wings?) on this graph?

http://img451.imageshack.us/img451/7199/fw190rollrate015in.jpg

The NACA 868 simply repeats this RAE curve. I think the report was prepeared in 1943, curious coincidence, at the same time the new Mk21 wings were tested with a MkV (hint, hint..). Maybe that's why the curves are so different than the others..


I ask because the all the other tests I have seen, including the RAF reports conclusions, the pilot interviews seem to tell the exact opposite, ie. clipping the wing improves the roll rate at high speed with the planes which had inferior pair of ailerons (one of the acute problems during spifire production due to the many subcontractors involved), but has negligable effect on aircraft with good set of ailerons.

Dave Southwood also commented on Spitty roll rate, he said the peak roll was 4 4.5sec for a plane with Ellipitic wings (which is in good agreement with the NACA's own test and 3 secs on the clipped version. Which again beutfully agrees with all tests expect that one shown above showing the uber roll rate Spit V outrolling the 190, YET none of the pilots reported they could come close in real combat...

Abbuzze
03-08-2006, 02:24 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Buzzsaw-:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Abbuzze:
Buzz, did he real meant this plane, or did he just spoke about the ailerons?
And how do you know that this plane didn´t got some maintance before the test?

Even if this part is not related to the ailerons, does 3/4 inch of stick movement for the elevator to the first sign of stall sounds slack? All over this Spit don´t sound very sluggish. </div></BLOCKQUOTE>

The extremely effective elevator was a characteristic of all early Spitfires, up to and including the earlier V's, mostly the VA. Compared to U.S. aircraft, elevator response was very noticeable. This would be observed even if the controls were out of adjustment. This was not the case with ailerons, which had a more normal response than the elevator even when properly trimmed. This disharmony of controls was changed with the later models of the V when the elevator was rebalanced. I suspect this V was an A model which had upgraded ailerons, as opposed to originally being equipped with metal versions. That is likely why its elevator exhibited the characteristics you mention.

All you have to do is to look at the other three charts posted on this thread to see the large difference in rollrate between the NACA tested metal aileron equipped Spitfire and the RAF tested ones.

There are other charts out there, which also show the rollrate of the metal aileron Spitfire, and they again confirm the results obtained in the RAF tests. The NACA test was an anomaly and not representative of the real potential of the aircraft. </div></BLOCKQUOTE>

Ok, I didn´t say that all Spitfires should perform like this. Even in the test you posted, Spitfires with good and bad ailerons are mentioned.

But on the other side, if even allies "cross" test give such a different and uneven picture and if the NACA was not able to fix it on a british plane, then tests of german planes by REA or by US organisations are even more doubtable in the same manner.

ImpStarDuece
03-08-2006, 02:39 PM
Actually, NACA 868 doesn't simply repeat the test curves of the RAE report.

If you'll look again, notice that NACA 868 starts around 5 deg/sec higher than the RAE report and the drop in the roll rate past 250 mph is less sharp, being between 5 and 15 degrees/sec faster. The curves are similar in that their peaks are identical in speed and rate, but they are not the same.


The FW 190 in RAF tests may of been underperforming slightly, perhaps by as much as 20 deg/sec at peak roll rate. I have seen figures of 170-180 degrees a second posted elsewhere.

However, in US combat tests the FW-190A5/U4 they tested had improperly maintained and aligned alierons, dropping its roll rate to around 80 deg/sec, or less than half what is should of been doing. Still the US Navy report was that it was as good as a Corsair in the rolling plane and better than a Hellcat.

faustnik
03-08-2006, 03:18 PM
Wait, you switched gears on me Buzzsaw. I'm still looking at the roll rate stuff. http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

Very interesting pdf link you posted!!! http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif A lot of it over my head, but, still trying.

********************

On the roll rate subject? When did the Spitfire get metal covered aelerons? Where they always that way? Is there a big diference in roll rate between metal/fabric?

Buzzsaw-
03-08-2006, 04:44 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by faustnik:

Very interesting pdf link you posted!!! http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif A lot of it over my head...

</div></BLOCKQUOTE>

A lot of it is definitely over MY head... http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

But there are a lot of sections where even someone with limited aeronautical knowledge can see what design type is most effective.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by faustnik:

On the roll rate subject? When did the Spitfire get metal covered aelerons? Where they always that way? Is there a big diference in roll rate between metal/fabric?

</div></BLOCKQUOTE>

AFAIK:

The earliest Spits to get metal ailerons were late model Spit II's, but that was an upgrade, not from the factory. The initial Spit VA's were equipped with fabric ailerons, but about halfway through their production run, they came from the factory with metal ones.

It made a huge difference to rollrate, the relevant chart has already been posted, this one by NACA:

http://img324.imageshack.us/img324/2443/7151094126808rollratespithurri.jpg

The Spit I's and II's we get in BoB will roll much worse than the Spit V's we have in the game, which are metal aileron equipped.

(so should the 109E1's and E3's)

faustnik
03-08-2006, 05:42 PM
Thanks. http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

Buzzsaw-
03-08-2006, 05:57 PM
Salute

Both the 109E and early Spitfires had problems with their rollrates being insufficient at high speeds.

The British improved their Spitfires' lateral response by going to metal ailerons, the Germans accomplished the same by doing a complete wing re-design, (along with fuselage) which resulted in the F and later models.

The Germans never went to metal ailerons, they retained the fabric covering. There were issues with wing loss at high speed when ailerons were used vigourously, so perhaps they were concerned about that.

Blutarski2004
03-09-2006, 12:39 PM
From THE DEVELOPMENT OF THE SPITFIRE AND SEAFIRE, a Dec 1946 address to the Royal Aeronautical Society by J Smith, Chief Designer for Supermarine from 1938 through the war years.


Results of Supermarine flight trial roll rate tests comparing Spitfires fitted with different types of ailerons:

Equivalent ..... Steady Rate of Roll in Degrees per Second
Airspeed

---------------Test A-------Test B-------Test C

150 mph-------87-----------87-----------(b)
170mph--------93 (peak)----93-----------65
200 mph-------75----------105 (peak)----73
250 mph-------57-----------93-----------96
300 mph-------40-----------78----------118 (peak)
350 mph-------27-----------60-----------90
375 mph-------20-----------49-----------75
400 mph-------(a)----------40-----------70

Note: values are drawn from a graph by eye, so may differ by a degree or two from actual number.

Test A: Mk V Spitfire w/ fabric-covered Frise type ailerons.
Test B: Mk V Spitfire w/ metal-covered Frise type ailerons.
Test C: Mk 21 Spitfire w/ "plain ailerons w/ tabs".

(a) graph ends at 375mph.
(b) no graph value recorded.


And ...............


A graph which charted required stick forces -

Equivalent ..... Stick Force in Pounds to apply 1/4 aileron
Airspeed

---------------Test A-------Test B-------Test C

200 mph--------8------------4------------7
250 mph-------15------------5------------9
300 mph-------26------------7-----------13
350 mph-------43------------9-----------18
375 mph-------56-----------10-----------21
400 mph-------(a)-----------12----------24

Test A: Mk V Spitfire w/ fabric-covered Frise type ailerons.
Test B: Mk V Spitfire w/ metal-covered Frise type ailerons.
Test C: Mk 21 Spitfire w/ "plain ailerons w/ tabs".

(a) graph ends at 375mph.


-----


Looking at the values for Test B, it is interesting to note that max roll rate comes at a speed (200 mph) where stick effort = only 4 pounds to apply 1/4 aileron. Since maximum lateral stick effort is supposedly somewhere in the 40-50 lb world, something else must be in play to limit maximum roll rate to such an apparently low speed. Either the stick effort per increment of aileron deflection is not linear, or there is a limiting effect produced by torsional effects upon the wings, or both.

Hmmmmmm.


-----


One thing to think about regarding roll rate -

60 degree bank = a 2G turn.
70 degree bank = a 3G turn.
75 degree bank = a 4G turn.
80 degree bank = close to a 6G turn.

Even a 5 or 10 degree difference in roll rate per second can be very meaningful in terms of an ability to enter a tighter turn faster. If my roll rate is 10 degrees per second faster than yours, I can get into a 6G turn condition in the same time it takes you to achieve a 3G turn condition.

Hmmmm.



Enjoy.

Abbuzze
03-09-2006, 03:45 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Blutarski2004:

Looking at the values for Test B, it is interesting to note that max roll rate comes at a speed (200 mph) where stick effort = only 4 pounds to apply 1/4 aileron. Since maximum lateral stick effort is supposedly somewhere in the 40-50 lb world, something else must be in play to limit maximum roll rate to such an apparently low speed. Either the stick effort per increment of aileron deflection is not linear, or there is a limiting effect produced by torsional effects upon the wings, or both.
</div></BLOCKQUOTE>

It´s the layout of the spitfire ailerons, even if maybe the roll rate in the test posted by me is to low, the principle charakteristik should be ok.
Spits has a large maximum aileron deflection, this gave this plane very small forces and high roll rate, but with increasing speed, the pilot couldn´t hold max deflection, because of very fast increasing forces, reducing deflection, gave a large punishment in rollrate.

From "my" test:
The Ailerons weere sufficently effective at low speeds, and were relatively light at small deflections in high speed flight. The forces requred to obtain high rolling velocities in high-speed fligh were considered excessive.
http://mitglied.lycos.de/p123/bilder/spitfire%20ailerons%20text.jpg


This fits to your observation.

WWMaxGunz
03-09-2006, 04:54 PM
Just how long and far around does the roll have to go before you get those steady rates?
Banking up to 45 or 60 degrees is not just divide the max rate by desired angle for time.

Blutarski2004
03-09-2006, 05:12 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by WWMaxGunz:
Just how long and far around does the roll have to go before you get those steady rates?
Banking up to 45 or 60 degrees is not just divide the max rate by desired angle for time. </div></BLOCKQUOTE>

Gunz,

You're perfectly correct, but all aircraft will display a period of acceleration between zero roll state and maximum steady roll rate. The real question is whether there is a meaningful difference in the roll acceleration rates from plane to plane. For any given aircraft configuration, I'd theorize that roll acceleration is PROBABLY related somehow to the maximum steady state roll rate at any given speed. If so, then the faster rolling plane will probably also have an advantage in roll acceleration.

Kettenhunde
03-09-2006, 09:18 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The extremely effective elevator was a characteristic of all early Spitfires, up to and including the earlier V's, mostly the VA. </div></BLOCKQUOTE>


Another stability and control issue. Are you saying this flaw was an advantage?

Supermarine and the RAE did not think so and promptly corrected it with bob weights.

http://img17.imagevenue.com/loc24/th_62731_spits1.jpg (http://img17.imagevenue.com/img.php?loc=loc24&image=62731_spits1.jpg)http://img15.imagevenue.com/loc24/th_62736_bobweightopinion.jpg (http://img15.imagevenue.com/img.php?loc=loc24&image=62736_bobweightopinion.jpg)http://img101.imagevenue.com/loc24/th_62741_bob_weights_results.jpg (http://img101.imagevenue.com/img.php?loc=loc24&image=62741_bob_weights_results.jpg)

What you are thinking of is rate of angle change. A characteristic that has absolutely nothing to do with stick forces experienced due to flow separation at the control surface. Rate of angle change is a function of the ratio of elevator surface to horizontal stabilizer surface.
http://img131.imagevenue.com/loc110/th_63370_angle_rate_of_change.jpg (http://img131.imagevenue.com/img.php?loc=loc110&image=63370_angle_rate_of_change.jpg)

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The real question is whether there is a meaningful difference in the roll acceleration rates from plane to plane. </div></BLOCKQUOTE>

Yes there is a difference from plane to plane.

The Spitfires problems in reaching it's ADM standard stem from flow separation at the aileron. Metal or fabric ailerons did not correct it. Only a wing redesign would have corrected it. This also led to the high stick force per G in the rolling plane and poor control harmony.

http://img124.imagevenue.com/loc24/th_62886_spitwing1.jpg (http://img124.imagevenue.com/img.php?loc=loc24&image=62886_spitwing1.jpg)http://img16.imagevenue.com/loc24/th_62886_spitwing2.jpg (http://img16.imagevenue.com/img.php?loc=loc24&image=62886_spitwing2.jpg)http://img139.imagevenue.com/loc24/th_62892_spitwing3.jpg (http://img139.imagevenue.com/img.php?loc=loc24&image=62892_spitwing3.jpg)http://img103.imagevenue.com/loc24/th_62896_spitwing4.jpg (http://img103.imagevenue.com/img.php?loc=loc24&image=62896_spitwing4.jpg)
http://img142.imagevenue.com/loc24/th_62901_spitwing5.jpg (http://img142.imagevenue.com/img.php?loc=loc24&image=62901_spitwing5.jpg)

This is evident in the ADM standard to 45 degree calculated times vs measurements found in RAE 1231.

http://img105.imagevenue.com/loc24/th_63961_ADMstandard45.jpg (http://img105.imagevenue.com/img.php?loc=loc24&image=63961_ADMstandard45.jpg)http://img25.imagevenue.com/loc24/th_63966_Spit_Mustang_roll_comparison.jpg (http://img25.imagevenue.com/img.php?loc=loc24&image=63966_Spit_Mustang_roll_comparison.jpg)http://img101.imagevenue.com/loc24/th_63971_Spitfireailerons.jpg (http://img101.imagevenue.com/img.php?loc=loc24&image=63971_Spitfireailerons.jpg)http://img109.imagevenue.com/loc24/th_63975_Spitfireailerons2.jpg (http://img109.imagevenue.com/img.php?loc=loc24&image=63975_Spitfireailerons2.jpg)


I have 4-5 reports on the rolling ability and the flying characteristics of the Spitfire. PM me if you would like a copy.

All the best,

Crumpp

Buzzsaw-
03-09-2006, 09:54 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The extremely effective elevator was a characteristic of all early Spitfires, up to and including the earlier V's, mostly the VA. </div></BLOCKQUOTE>

Another stability and control issue. Are you saying this flaw was an advantage?

</div></BLOCKQUOTE>

Did it sound like I said it was an advantage????

No.

The early Spitfire had a number of design aspects which could be improved, among them the fabric ailerons and the elevators. Supermarine did a fine job of correcting these defects, the Spitfire V when equipped with metal ailerons and elevator bobweight was probably the most maneuverable and responsive version ever made.

OldMan____
03-10-2006, 07:33 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Blutarski2004:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by WWMaxGunz:
Just how long and far around does the roll have to go before you get those steady rates?
Banking up to 45 or 60 degrees is not just divide the max rate by desired angle for time. </div></BLOCKQUOTE>

Gunz,

You're perfectly correct, but all aircraft will display a period of acceleration between zero roll state and maximum steady roll rate. The real question is whether there is a meaningful difference in the roll acceleration rates from plane to plane. For any given aircraft configuration, I'd theorize that roll acceleration is PROBABLY related somehow to the maximum steady state roll rate at any given speed. If so, then the faster rolling plane will probably also have an advantage in roll acceleration. </div></BLOCKQUOTE>

Not necessarily, the inertia tensors are quite relevant on this issue while they are not very meaninglful in max roll rate.

faustnik
03-10-2006, 12:30 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Blutarski2004:
---------------Test A-------Test B-------Test C

150 mph-------87-----------87-----------(b)
170mph--------93 (peak)----93-----------65
200 mph-------75----------105 (peak)----73
250 mph-------57-----------93-----------96
300 mph-------40-----------78----------118 (peak)
350 mph-------27-----------60-----------90
375 mph-------20-----------49-----------75
400 mph-------(a)----------40-----------70
</div></BLOCKQUOTE>

Thanks very much for posting that, it's really helpful for comparing the aeleron types! http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

WWMaxGunz
03-11-2006, 12:03 AM
Has anyone heard or read of a 'time to bank angle' table?

ImpStarDuece
03-11-2006, 03:05 AM
I have one on my hard-drive somewhere for a Spit Mk XII, i'll dig it up when I have some time.