Spit IIa

[CWMV]

I do the same, trust me.
I think both of our favorite aircraft need new FM's!

[David198502]

...yes as realistic as possible please,...and please do not tweak them in unrealisic manners just to ensure online balance!!
make them as they were, with all their advantages and drawbacks, its supposed to be a SIM!

[TomcatViP]

Guys are you even reading the charts IvanK hve just posted ? Those are great stuff and real dynamite.

Before complaining abt the lack of boost on the spit pls do start to question yourself about how the Spit is turning (indefinitely level) in game and hold E.

Regarding the neg G cut-out, I think it has been extensively debated to the point that it s rather insulting to read that it has not been modeled in a real (and honest ) manner.

Damn, we even hve a video of a latter model itching the camera while flying upside down: : pump up the volume and L.I.S.T.E.N by yourself !

[SEE]

Tomcat, I stated the Neg G is 'debatable' which means it may be correct or it may be incorrect - hence the discussion. The other aspects of FM I pointed out with the Mk1 are incorrect for that model/timeperiod and, on many servers,
the only Spit in the Plane set.

You seem to have an issue with the Spit, that's OK, some posters have issues with the BFs but that's not OK?

Read my post....(the Spit Mk1 is very capable at altitude and handles beautifully) I do not feel at a disadvantage against any of the BF's even with its current modelling but that does not mean it is correct either. The Boost data for the Spit Mk1 has been extracted from the FM file....it adds 0.002 Ibs/sq ...are you seriousley telling me that is correct or a signicant figure?

+1 to David198502 last post.

[bugmenot]

Originally Posted by IvanK

The chart is one of the earliest plan Fan plots (or "Dog house plot" in US terms) that I have seen. As such its straight Energy Manoeuvrability theory that is Excess Power (ps) applied to the turning problem. As such it takes into account the total Airframe engine combination so Wing loading,planform,wing section etc is part and parcel of plot. The actual RAE derivation of these charts is discussed in great detail in AVIA 6/2366 RAE report "Notes on the dogfight" A more detailed version of the Spit fan plot chart from this report is shown below. In this case the study also takes into account various extrapolated wing areas and therefore wing loading etc.



I dont agree that their assumptions were made on false grounds. Everything I have read in these reports indicates to me that the boffins doing this work were really on top of their game. Here is some of the data they were using in this report obtained from a physical specimen BF109E3:





The USN also produced a comprehensive study on turn performance on the F2B (Buffalo) that is equally involved and again is based on straight out EM theory applied to the turn problem and again chock full of fan plots.

Here is another chart from the same source source document as the original Fan plot came from (AVIA 5/2394 "Messerschmitt Me.109 Handling and Manoeuvrability Tests" which is a pretty exhaustive 63 page document. This chart provides similar data to the fan plot but perhaps in a more easily digestible format as both Spitfire and 109 plots are overlayed on the same chart.

The problem with Me performance numbers

Case: Bf.109E

"Another problem is with the test itself, when compared to a Spitfire. Overall the accuracy of the test suffers from the fact that it was flown with a crash landed plane wirh a worn, several years old engine producing less power than usual. It was then flown against a brand new Spitfire with a 1940 engine. As shown by the test data, the turns were made in the 120mph range which is too slow for the 109 slats to be deployed, which doesn't compare the maximum turning abilities of each aircraft."

http://www.virtualpilots.fi/feature/...s/#testflights

[TomcatViP]

Originally Posted by SEE

You seem to have an issue with the Spit, that's OK, some posters have issues with the BFs but that's not OK?

I HVE NO ISSUE WITH THE SPIT. Pls bear that in mind. I want that sim to be real and not an ego contest with Ninja planes. Think about you hvn't eared me criticizing the hurri.

I am not trying to impose my view. I think that talking abt the subject is interesting and in no way do I feel perso implicated in "one side or another".

I wld be pleased to fly the Spit as soon its FM won't look likes anymore that of a flying carpet.

Originally Posted by SEE

The Boost data for the Spit Mk1 has been extracted from the FM file....it adds 0.002 Ibs/sq ...are you seriousley telling me that is correct or a signicant figure?

I am only stating that as the drag is contestable (the E retention) pointing the way it turn in the sim, the Boost can't be accurate or this plane will zoom or accelerate like an F16.

In other words : let them fix the FM and then I guess that the boost restraint will be lifted.

If you fly the hurri you'd see that the boost is already a joke (infinite time, extra cooling...). But as the hurri drag and E seems to be correctly modeled, it does not give it surrealistic perfs (just optimistic ones).

I guess you can't do that on the spit as it is for now

Last but not least, it has been shown that the 12lb boost can't be what it is seen by some here (we shld speak here more abt a "WunderBoost")

[SEE]

Points taken Tomcat...no arguments with your last post.

It does seem odd that the devs state in the patch notes ' for Spits, 'boost cut out' can now be enabled/disabled' - what they don't say is that it does sweet FA!.....

[IvanK]

""Another problem is with the test itself, when compared to a Spitfire. Overall the accuracy of the test suffers from the fact that it was flown with a crash landed plane wirh a worn, several years old engine producing less power than usual. It was then flown against a brand new Spitfire with a 1940 engine. As shown by the test data, the turns were made in the 120mph range which is too slow for the 109 slats to be deployed, which doesn't compare the maximum turning abilities of each aircraft."

Of course the old clapped out engine theory will be presented. The data is the best available and is presented as is. I am not sure about the clapped out bit either. that is a readers assumption, and is not reflected in the report which is very thorough.

as to the slat comment ... The original author shows a fundamental lack of basic aerodynamic knowledge. Slat deployment is a function of AOA. The Slats deploy at a specific AOA every time not at an IAS. The AOA remains the same and IAS at which the slats deploy will vary as a function of G .... BUT ALWAYS AT THE SAME AOA. But the corker is the bit " the turns were made in the 120mph range which is too slow for the 109 slats to be deployed" ... you are not serious surely ! Think about it Slats are High AOA slow speed regime devices they are more likely to deploy at the slower speed (i.e. higher AOA).

For the record here are the 1G slat deployment speeds as found by the RAE in AVIA 6/2394 Messerschmitt Me.109 Handling and Manoeuvrability Tests. Its worth noting a 9Mph diff between the ASI reading and the trailing static source.

[Kurfürst]

Hmm, Werknummer 1034s engine problems (seems lubrication related) are documented in both French trial reports and RR reports. Its noteworthy that already in French trials the plane was loosing boost at altitude for some reason - I suspect French lubricants did not go well with the DB engines hydraulic supercharger clutch. But that's besides the point, because the British did not measure turn times for the 109E in flight tests, nor they did measure times for the Spitfire either.

The doghouse charts you presented are inidrectly based on stall speed measurements of the Spitfire. Now, those long enough to remember Ubi there were a number of threads discussing the difficulties of defining and measuring stall speeds, so there is a degree of potential inaccuracy with this base data already. From the established stall speeds of the Spitifre, they estimated its lift coefficient; they used this estimate to guesstimate the 109's lift coefficient. These guesstimates were used to calculate the doghouse charts you presented, using known power curves.

In short, they are calculated estimates with a bit shaky base data.

As to Bf 109E turn times, these are known from German/Mtt calculations, and are given as 18.92 secs for a sustained turn at 0m altitude using 990 PS or 1.3ata output of the DB 601A. (note British guesstimate is for 12k feet so the figures are not directly comparable).

As to Bf 109E(-1, -3, -4) performane in the sim, I note that in the early versions of COD the 109E just can't go past around 460 using 1.35ata, whereas the actual specifications for the type gives top speed as 500 kph at SL and 570 kph at critical altitude, with plus/minus 5% tolerance on production aircraft (so actual production aircraft fell between ca. 545 - 595 kph). Can it now reach its specs in the new beta patch?

The aileron up/down travel angle for the 109E is very interesting though - it seems the F-K increased the travel angle a lot (and changed to Frise type ailerons), though I wonder why. Better control response times, even though the E was already noted as brisk for aileron control response?

Anyway for a reality check with a new patch I always use to try if I can break the Spitty in two by madly pulling back the stick, something that would be suicidal in the real one with a stick force of a mere 4 lbs / G. It isn't possible in the sim. In fact, I did nto manage to break any aircraft in the sim, no wonder what stupid maneuvers I tried.

The increased aileron travel for the F to K series might be at least partially to counter the increased roll inertia and roll drag with the curved wingtips (hence longer wingspan).

But interesting post, Kurfurst.

I dunno about the doghouse chart and how they produced it but don't you think that they at least verified their method by test flying the Spit?

Has anyone made a test about turn times as implemented in game?