Kurfürst

You have posted Spitfire and 109 elevator forces. Topic is 109 aileron forces. Stick to it, if you'd please.

Looking at DavidRed's trial (thanks David for such through test!) I think the problem is clearly that our Bf 109 pilot's physical attributes are... well... probably modeled after that of Woody Allen, at least as far as his physical abilities go. This virtual chump cannot deflect to ailerons/stick on the 109 fully until down to about 280 kph indicated at about 2.5-3 km altitude, or about 300-310 km/h TAS. Looking at the Bf 109F roll graph this would tell you he isn't putting more than about 7.5 kg on the stick. The Bf 109F roll graph reposted by Rel4y shows that the 15 degree (i.e. full stick sideways deflection) force limit at 300 km/h TAS is about 7.5 kg sideways force, i.e. at 7.5 kg you can fully deflect the stick on the 109F (K) at 300 km/h TAS at 3 km altitude. And 7.5 kg is a ridiculously low force limit, and for any reasonable physical build it should be roughly double than that with even one hand. Usually I see 25-30 pounds shown in tests, and for example the real pilot in the DVL 109F roll test was recorded in one graph to apply cc. 12 kg on the stick within roughly 0.3 sec. As far as I know, the DCS physical force model works like that even higher force threshold are possible (pilot uses both hands on stick), but the speed of applying deflection will slow down (pilot struggling to apply higher forces). Naturally the amount of force considerably varies from person to person, and the Gov'nor of California would probably tell you jokes while exerting the full 30 kg force with one hand. But any reasonably fit man should be able to do 10-15 kg with one and so IMO our current virtual pilot struggling to go anywhere above 7.5 kg is a sign that he should have been thrown off the Taygetus right after his coding. Well, in any case, he will probably die from over straining himself once the Spit is out, given the forces acting on the aileron there, the 109 is like lifting a feather compared to that.. Probably the same goes to elevator forces. The virtual pilot is probably just too week.

Dive limit for the Bf 109K (and all 109G with the enlarged rudder) was increased to 850 km/h. The dive tested Bf 109F/G hybrid (with early tall tail was dived to 906 km/h. See 109K operating manual Normal speed gauge (IAS) Dive limits for altitude compensating speed gauge (same as in Me 262)

Why does it start to roll to the right in the first place? Even with power off etc? Profile on rudder being the reason perhaps?

Oh, the 'issue' that you have repeatadly claimed not to exist because there were no stability issues in the first place...? Curious, how selective one can be with his books isn't it. Anyway, I am so glad that resources are being spent on a detail like this while other, final release modules basically miss their whole weapons loadout...

Ok, so if I gather right, the Drag Coefficient changes are not /not planned to be implemented, but to the second part of question (DeltaCLmax change from gun port condition) is/will be implemented, hence the comment effecting stall characteristics..?

Thanks for the answer YoYo, but is this a yes or no? Is the effect modeled or not?

I would risk saying it would make more difference to the overall fidelity of the FMs than, say, a request to a tiny change the 3D model of the elevator on the Spitfire, on grounds that though its existed in the period, it was not typical enough to satisfy a real gourmet of combat aviation. Or that the shape of cannon barrel is not very typical for a certain batch of Spitfire over Normandy. I'd call these small, tiny, minuscule details about which personally I cannot care less, but its apparently a matter of paramount importance for some guys. Oh well, now we have a different slightly different shaped balance on the Spit, huzzah. In contrast, a change of 0,05 to 0.12 in Cl is not entirely small or insignificant. At least that's what I gather from some long raging blood feuds fought with religious zeal over a difference of 0.18.:megalol:

Yes, that's the report I had in mind, thank you for linking it. Notice that the P-51B gun ports are rather close in their design - obviously the primary consideration was maintenance. The outer MGs on the Spitfire were kind of an afterthought, weren't they, after the requirement for +4 additional MGs arose, they had to enlarge the wing to its well known form, and fit those extra MGs in it whereever possible. Hence their seemingly random arrangement. See the attached picture from the report you linked, for the P-51B installation. On page 17 of this report there is a table, noting DeltaCLmax = -0.05 for the "fabric torn" condition (and -0.12 for the completely unsealed gunport). The curve marked with "+" ("tape torn" rather than completely "unsealed") appear to be most relevant for the change in Drag Coefficient and Lift Coefficient. To me it appears that the drag increase is proportional to Angle of Attack change (i.e. both negative and positive Cl change increase drag with the 'torn' and 'unsealed' installations) Analoges for the cannon installation are also available in the report for Drag increase with Cl increase. My question to the developers is the following: is this Cd / Cl effect from the tape being torn on the gun ports is being simulated in DCS - i.e. for the P-51D and upcoming Spitfire IX LF? Does the FM differentiate between sealed and 'fired' gun ports?

Indeed. AFAIK gun ports over the wing do decrease Cl under dynamic conditions, so they do effect overall drag, through loss of lift, which is the more pronounced effect. I wonder if this will be modelled in the FM - i.e. CL change before/after the guns are fired...? And those gun ports weren't exactly small either, rifle caliber MGs barrels are fairly thin themselves, but I suppose the designers had to allow for some air to flow through to allow for cooling of barrel and the gun.

Interesting info rel4y, thanks a lot.

What's the exact difference between Leuchtspur and Glimmspur type tracers? Just the intensity of the light? Does anyone know?

That's really a first for someone to call the 109... slow. Huh? Sorry but the D9 is the ultimate 190, appearing head to head with the K4. And I am always wondering why people seem to be so hung up on the Ta 152. What was so hot about it, really, apart from high altitude performance? ? That some guy made a mock up fight with Tempest and outturned them, which is to say they turned better than a fighter never known for its turn ability...? The 152 was a great plane for one thing, a specialized high altitude fighter. Otherwise... nothing special anywhere under its optimum extreme altitudes. 109 'fanboys' do tend to forget about because the 109 operated on the same principle, as far as the pilot workload goes. Automatic everything, HOTAS engine operation with a single lever. The Kommadogereats was more advanced as far as engine control went (more stuff was set in the background by it), though it had a rather problematic start. From the practical point of view, as far as pilot workload went, it offered nothing over the single lever control in the 109. The super-advanced engine control is the narritive from the RAF perspective. From the air force that's fighters are known for an increadibly complicated engine startup and flight instrument and switches placed completely randomly in the cocpit. But the same narrative was made of the 109F a year earlier when they inspected it (to qoute: 'The fact that the airscrew is fully automatic, and the oil and coolant temperatures thermostatically controlled, helps to make the aircraft a simple fighting machine, as the only things then occupying the pilot's attention in combat are his throttle, flying controls and guns.' ) And all electronic systems, YAY for that, yay for electric trim, propeller pitch, flaps, guns, and undercarriage, so just in case your battery fails, everything is gone at the same time and you don't have to worry about much any more, since its gone already. Here's for example what the German's said about electric trimming on the 190. "The electric trim is currently actuated by a rocker arm, that is very small and also almost level with the panel. The trimming must be able to be operated at all times, and thisrequires that the rocker switch must be significantly increased in size so that it is at least 1 to 1 1/2 cm above the panel." There you go, fiddle with a tiny electric switch in thick pilot gloves, in a cocpit that heats up to 45 degrees Celsius in the summer.. A smart design? Without doubt. Did it had advantages over the 109 - without doubt, but those were mainly outside flight performance, such as capable of carrying a more heavier armament and ordnance, a tougher airframe that withstood harsh/belly landings much better, having a very wide undercarriage, better search view. The end of all design ergonomics and smart solutions, from which it follows that the same MUST be also true to its flight performance, despite the fact its a 4 ton machine with a very high wingloading...? Hardly. It was a great plane, well though out. A great many things and design standards are very similiar to those used on the 109 in fact, and the things it improved upon it - beefier structure and powerplant - are also a reason why its flight performance in some areas is weaker or better. Which brings us to the question on the thread. Why the 190 is hyped so much in Anglo-Saxon literature? The answer is easy, RAF Fighter Command took a bad hammering in 1941 from 109Fs, and a just as bad one from 190As in 1942. Precisly for the same reasons - the advantage of the defender, more experienced fighter pilot cadre, and better planes to boot. The exhange ratio was massively against RAF FC, the 190A did not change that at all. When the Luftwaffe introduced the 190A over France and practically replaced the 109s for all but high altitude work (and only in France - not because it was super-elite but for the profane reason that it's early engine reliability record was so shitty they considered it unfit for any other theatre than the French 'backyard' where it would fight over friendly terriotory and wouldn't loose pilots to engines stopping mid-air..!), finally they had an excuse to cease those pointless incurcions over France. The new, sinister and completely unknown 'super fighter' of the enemy. Hence the narrative from Price et all, they are all rooted in the panic described in old Air Intelligence papers. You know, the papers with all the funny stuff made up from heresay, like He 112 fighters, Messerschmitt 'Jaguars' or Bf 109s with DB 603s... and 'Curtiss Hawks' appearing over France in 1942.

109K Rüstsaetze from manual

Nothing, since the DCS 51 at 67" already flies as fast as the real ones at 72"...

As if wing-loading having ANYTHING to do with critical angle of attack of a wing design. :doh: A statement which merely shows that you mix up stalling and spinning out of control. On the videos, all I can see is that the 109 is in landing configuration, and at its landing configuration stall speed of cc 150 km/h, it rapidly looses altitude, which means the inner wings are already stalling, but the outer ones are still hangin onto the air, because the slats mean they would stall only at a higher AoA than the inner wing. Which is why the ailerons are still effective and the plane can be effectively flown in semi-stalled condition. Which is exactly why the slats are there. To maintain control and prevent spinning. Which is exactly why the Bf 109 was choosen in the end against its Heinkel rivel during the final acceptence tests. Which is exactly why it was designed in such way - spin resistance was something the Luftwaffe demanded from its new fighter. Which is exactly does what it needs to do.

Exactly. And its no small power when it comes to driving that supercharger - the Griffon for example, noted for its very powerful supercharger, used some 600 horsepower (yes, SIX hundred) just to run the supercharger at full speed. Other may have used less, but its still in the hundreds of horsepower digits. Now, quite typically for a WW2 engine, fuel consumption was around 235 grams/HP/h, in other words just to drive the (Griffon) supercharger you are burning 0,235 kg/HP/h, or 140 kg (cc. 185 liter) of fuel every hour. Just for the supercharger, because the driving the prop consumes the rest. You are entirely correct that very high levels of supercharging is a very straightforward way to increase power. But it comes at a cost higher fuel consumption (meaning that you have to carry more fuel) and on the long term because of dimenishing returns and efficency When you are using high boost rates, you would probably want to stick to lower compression ratios (which again are not so good for engine effiency, as for the same amount of fuel burned, there is less useful mechanical work), to avoid extreme end pressures that your fuel cannot take without detonation. After a while you probably want to use higher lead content or aromatic fuel for the same reason, which leads to to deposits and corrosion in the engine. Sooner or later you will also need some sort of intercooling (and the drag and weight of the intercooler radiators and plumbing associated with it) to deal with the extreme heating up of the charge in supercharger itself (again leading again to fuel detonation). Which is probably the answer why the DB engines are lighter and more fuel efficient BTW - they tended to operate at moderate supercharging (the large volume needed rather less boosting), using rather high compression ratios and did not used intercoolers at all (apart from the similar MW injection on later models). A designer has to weight all that. There is no point in an engine developing twice the horsepower if its increased weight (of the whole powerplant - inlcuidng fuel reserves, radiators, oil tanks, propellor size and weight) and size leads to such an increase in drag that the net gain in thrust is marginal, or not there at all. Designing a new, larger block and making it work reliably is a matter of many years, and in wartime, you do not have the luxury of waiting for a new block. In wartime, you have to make the most out of the existing one and keep it competitive.

I wonder what the tail incidence was set to during this "test". Given that the flaps appear to be fully down, its not unlikely that the tail incidence was also set nose heavy and thus interfering with the "fully" back stick. In short, it looks like a landing configuration and someone was trying to land mid air, which obviously did not work out but looked silly, hence this "bug" report about airplanes. Flying. At high angle of attack. With all high lift devices (slats, flaps). Also known as "aircraft fly".

Pretty cool detail, huh? :)

It was just a quick reflection of "running out of MW" suggestion, so I run a bit of number crunching to see how viable it would be in DCS. Well, not very much. As for the engine, the Merlin is not very economical to be honest, its a very hungry little wasp with a lot of supercharging going on at rather low compression ratios and higher RPMs to compensate for the lower displacement. Its all about producing power and not at all about fuel efficiency. In modern engine marketing terms, you could call it a "downsized" engine vs a "rightsized" engine, but its feels a rather odd description for something that weights almost a ton and displaces some 27 liters. :D Now as for the number crunching, in the Spit IX LF, you 85 gallons being consumed by the Merlin 66 at 150 gallon per hour rate when at full +18 boost. This means running it flat out all time would let you run the engine for 34 minutes or so. In the 109K-4, you 88 gallons (i.e. 400 liters) of avgas being consumed by the DB 605DB at 610 liter (134 gallons) per hour rate when at full 1,8 ata boost, plus you have the 85 liter MW tank, the contents of which being injected at a rate of 180 liter hour. The MW tank is thus dry after 28 minutes, but you still have about 100 liters left (I think this was intentional, as the "red fuel lamp" on the 109 would light up at 100 liters, signalling you need to RTB). At this point the IXLF has about 14 gallons left in the tank, or about 5 minutes worth, so its high time to look for a suitable landing place or you will soon do so as a glider. 100 liters is enough for about 12 minutes of operation at the max allowed 30 minutes rating once MW runs out - and on that rating the 109K can still match the IX LF speed at full output, and is in fact still quite a bit faster at the very high altitudes, like 700 and over. Of course all this is very very theoretical, since nobody flies likes this, and no fight should last for like 30 minutes... and at constant full power, and fuel tanks cant be emptied either for the last drop of fuel. But the bottomline is, you definitely can't bet on him running out of MW fluid.

IIRC it had something to do with the arming of the bombs fuzes... perhaps before OR after repeasey - but cant recall exactly.

If you run out of MW-50, it means you are still as fast as him, except he is about to run out of fuel in a minute or two. ;) Sooo... bis zum Enddeciliter! :D

Like P-51, i.e. separated throttle and RPM which has to be moved and set in proper sequence to avoid engine damage. I wonder if that, underrev and the like are part of the engine model. So, no automated controls, albeit allegedly, a limited number of later Spits supposed to had a sort of primitive imitation of it, where the throttle and rpm could be moved forward together by a simple mechanical device.

Sloped armor wasnt anything new, and in fact it has been used long before. Often however, mostly likely because of internal space considerations and the lack of really powerful AT weapons, they could opt for simpler vertical plates. As for how original the T-34 itself was, take a look at the French FCM 36... familiar lines? The T-34 did little more than to took progression one step further into a more potent BT series like fast tank and then evolved from there, and as we can see, with strong French roots - the V2 diesel itself was based on a French airship diesel engine. In fact the Panther took very little from the T-34, apart from the general hull shape which was strongly inspired and carried over of course, with a lots of rethink. The Panther for example has a front drive, torsion bar suspension with interleaved large road wheels (giving its famous riding characteristics) fuel tanks in the rear sides of the engine, a mid turret with a turret basket and ammo in the sponsoons and escape hatches at the top of the hull, and of course retained the petrol engine. In comparison the T-34 had the fuel in the sloped sides, ammo under the frontal mounted turret and without a turret basket, with the rear mostly occupied by a giant diesel engine and a rear drive, a rather simplistic Christie suspension with basic breaking/turning methods. As for the Christie suspension, it wasnt favoured, largely because it gave poor suspension characteristics and eats up the hull sides a lot, and even in the Panther, eventually everyone went with torsion bar suspension until replaced by hydraulic suspension in the latest MBTs.

Nice to hear that Sith, thanks for the feedback!