Spit/109 sea level speed comparisons in 1.08 beta patch

[bongodriver]

Originally Posted by Crumpp

I admit I have limited knowledge about airplanes. My expertise is lies.

fixed that for ya.

[ACE-OF-ACES]

Originally Posted by klem

More confusion because I understood the rough conversion to TAS is 2% per thousand feet

The key word being 'rough'

A few years back, while testing IL-2, I did a comparison between the gauge IAS to TAS values using the 'rough' conversion to the 'full' conversion using the IL-2 'internal' values obtained via SJacks ZINFOMOD.. I than graphed the two values side by side, at which point the word 'rough' came to light! In short this rule-of-thumb pilot real time in your head calculation is very 'rough', there are points (altitudes) where it is spot on, but there are other points (alts) where is is way off.

Originally Posted by klem

but I'm more inclined to trust the Z data and particularly Z_TAS.

Hopefully the soon to be released 'readme' will shed some light on the subject, but like you, I am leaning towards using some of the Z data values.. at least when it comes to speed measurements. They do seem to agree with the real world data better, at least for the few planes I have tested.

For now my plan is to provide both the Z and I values and let the user decide which to use with my CoD analysis tools that I provide online at www.flightsimtesting.com

[ATAG_Snapper]

Originally Posted by camber

Thank you MusseMus, that is very interesting!

In previous speed tests I put in the phrase that these comparisons were only valid if a 109 and Spit flying side by side showed the same speeds on their gauges. From your tests it looks like the answer is no! From flying in ATAG it is clear that 109s show a large speed advantage at all alts but perhaps not as much as the gayges suggest

camber

Definitely worth looking at -- good work. I see this question of airspeed gauge accuracy has been posed in the Questions thread, as it should be. Anything like this should be examined, IMHO, and I hope Ilya does. RAF aircraft need accurate instruments for navigation as well -- especially if cloud cover is someday introduced. Hopefully you will post a Bugtracker Report using your data as its basis.

Having said that, I must admit I'm not convinced that perceived major FM inequities lie just with simple instrument error. As the old saying goes, "Just because you're paranoid doesn't mean they're not out to get you.". The hundreds of hours (literally) most of us have virtually flown on type (for both sides) to believe this notwithstanding, the RAF models alone are hobbled with huge radiator drag, with radiator surface area assigned three times the surface area of the 109's TWO radiators combined, with the double whammy of the RAF rads being assigned a drag coefficient 40% greater than their 109 counterparts. This alone has the Spits and Hurries flying with a huge drogue chute behind them when the pilot tries to cool his glycol and oil even under normal operating conditions, let alone in a fast interception climb or actual combat.

Only when Engine Temperature Management is deactivated in the Realism Options do the Spits and 109's actually achieve parity in engine performance. By default, with ETM off, all radiators are closed (huge benefit for Spits, Hurries, small benefit for 109's), and all temps are now AI - regulated (again, huge benefit for RAF, smaller benefit for LW). This is wrong and must be corrected, instrument error or no instrument error.

The devs are aware of this, and they should be made aware of all instrument error -- including the dodgy Rate of Climb indicator in the RAF aircraft as well.

None of this is rocket science, it just remains if Ilya sees fit to order the corrections or not.

Plus, I want to emphasize how much I respect and support your hands on initiative and the work you've done, and sincerely wish for any and all instrument inaccuracies be fixed -- at least to authentic specs. I tend to agree with my colleague, Dutch, that if the radiator drag issue is remedied in the RAF aircraft that the FM's for both RAF and LW will be closer aligned in relative performance. And I certainly want accurate gauges!

[Kurfürst]

Originally Posted by ATAG_Snapper

The hundreds of hours (literally) most of us have virtually flown on type (for both sides) to believe this notwithstanding, the RAF models alone are hobbled with huge radiator drag, with radiator surface area assigned three times the surface area of the 109's TWO radiators combined, with the double whammy of the RAF rads being assigned a drag coefficient 40% greater than their 109 counterparts.

Is this a fact or a feeling? I have the relevant radiator areas, so what are the figures and from where?

The devs are aware of this, and they should be made aware of all instrument error -- including the dodgy Rate of Climb indicator in the RAF aircraft as well.

As I understand the indicators have "electric" and "mechanical" types in the sim. Could it be that real world RAF and LW preferred different type of instruments, and this is modelled (perhaps wrongly) in the sim?

[bongodriver]

As I understand the indicators have "electric" and "mechanical" types in the sim

only the RPM gauges.

[pstyle]

Originally Posted by Kurfürst

Is this a fact or a feeling? I have the relevant radiator areas, so what are the figures and from where?

Hey kufürst, Dutch put a wee post someplace about how thwy had measured this.. I don't have a link right now tho.

[ATAG_Snapper]

Originally Posted by Kurfürst

Is this a fact or a feeling? I have the relevant radiator areas, so what are the figures and from where?

Fact.

As I understand the indicators have "electric" and "mechanical" types in the sim. Could it be that real world RAF and LW preferred different type of instruments, and this is modelled (perhaps wrongly) in the sim?

That could well be, I'm only reporting what others have measured in sim.

[ATAG_Dutch]

Originally Posted by pstyle

Hey kufürst, Dutch put a wee post someplace about how thwy had measured this.. I don't have a link right now tho.

Hiya pstyle. I posted a video of the effect of radiator drag in the Spit alone. It's post #16 in this thread. This didn't actually measure the relative surface areas Snapper mentions.

Just thought I'd better clarify that.

[pstyle]

Originally Posted by ATAG_Dutch

Hiya pstyle. I posted a video of the effect of radiator drag in the Spit alone. This didn't actually measure the relative surface areas Snapper mentions.

Just thought I'd better clarify that.

Roger, cheers for the correction.

[JtD]

Originally Posted by Crumpp

No I am not. I am saying both aircraft are flying best turn performance.

I can't really know what you were trying to say, or what you are going to say, but you were exactly saying what I stated:

the Bf-109E3 is hopelessly outclassed IF it tries to match the Spitfire at the Spitfires best performance velocity

I'm happy to see that you now are saying something much more meaningful.