rel4y

I dont think 610 kph is justified, speed gains due to drag reduction dont indicate that. But after the update of the drag model the K4 should and hopefully will do 595 kph on the deck. The increase from 570 to 595 kph MSL speed should be the consequence solely of drag reduction if everything else is correct already. So I would conclude the update has not been implemented yet. It is not a rough estimate. It can be calculated from data of the measured G14 MSL level speed + measured speed gains due to drag reduction. This was stated in this thread and approved by Yo-Yo after which he updated the drag model. You can read all this info right here in this thread.

No hostility intended. I know you were involved in these cases. But this time again you quotet Yo-Yo before data of different aerodynamics were presented and later confirmed by Yo-Yo himself. So what is the point in that? If you would bring up new and unknown data I would be thrilled. I wouldnt mind making the 109 slower if historical data strongly indicates, since historical accuracy for me is the goal. But I cant see what your reasoning is to dispute already discussed and concluded points. Im sorry if I misunderstood you.

Did you actually read this thread solty? Pretty much everything you just threw in has already been discussed in detail.. Climb rate figures were calculations without engine thrust included, ingame measured climbing time to altitude closely resemble historical data, level speed figures were actual measurements, the DB605 engine model on the 109K4 agrees very well with historical data, the drag area used atm is that of a G10/late G14 not a K4, 605DB and 605DC are the same engine with a few screws turned, the Rechlin docs you presented are prototype data and likely do not present production line aircraft in terms of aerodynamic features and finally if P51 speed is historically incorrect find out the reasons and proove otherwise with solid documentation as done in this thread. I dont want to be rude, but I can not see a point to dispute this topic again if everything you just argued for has already been discussed. Now I dont agree with a MSL speed of above 595 km/h, because that is what historical (measured) data verifies.

Rudder 0 Aileron -6 Keeps the torque at speeds above 450 kph better under control imo.

I use the following settings with the keybinds "zoom in", "zoom out" and "zoom normal" setup on my joystick coolie hat. This basically gives me 3 usable zoom levels with FOV at 30, 90, and 110 for my 1080p 24" display. Works like a charme. :thumbup: CameraViewAngleLimits = {30.000000,110.000000}, tab.viewAngle = tab.viewAngle or 90

When jettisoning the MW50 the trim changes in flight, so in fact the tank is probably modeled now. I also noticed the horn sounds more muted. I cant howerver confirm a change in power on stall behavior. Maybe I am missing the comparison here. How do I roll back the version?

I just tested ingame, slat deployment starts at 6.8° AOA and is completed at about 7.3° AOA. Where did you get the 11-12° AOA number from Hummingbird? It seems a bit high to me, since 4-5° delta AOA, as well as correlating center of pressure shift on the wing is quite a lot. The forces pushing slats out and in must be just before/beyond equilibrium state and the gradual deployment being only due to non zero mass of the slat as well as slat rail friction. So correct me if I am wrong here but my sense of physics tells me, this margin just cannot be 4-5° AOA. Very nice pictures by the way! Its red 7 isnt it? Edit: So I took a look at the document I mentioned earlier and measured the speed at which slats deploy ingame. At 230 km/h (6.8° AOA) the slats began to deploy. The document mentions optimal speed at which slat deployment should start to be 230-240 km/h (Kampfleistung). So at least the start of deployment seems to be set pretty much to historical standard. wwiiaircraftperformance.org/me109/VB-109-10-E-42.pdf

That completely makes sense. I just assumed the margin of equilibrium in the forces pushing them in and out is small. The german tests I know talked about aprupt deployment at an specific speed or angle of attack. But may I ask how G loading affects the deployment?

There is an inner circle going beyond the 750 mark which indicated up to 900 km/h. It was used from G2 (G1) onwards, maybe not exclusively. The F4 still had the old type.

If slats are installed correctly and you keep the ball centered, slat deployment should be symmetrical. Some pilots encountered unsymmetrical/ early/ late slat deployment which caused trouble, so a guideline for correct installation was made. There is a document on kurfurst.org and/or wwiiaircraftperformance.org concerning the resolvement of this issue I believe. Also slats either deploy fully or not at all, aerodynamic forces being strong enough for split second deployment once preset AOA is reached. Jcomm thanks for posting Klaus Plasas insight. That is quite interesting, since wartime pilots talk about a wide margin of pre stall buffeting/ lots of warning before stall and a loud bang when slats deploy. Infact even loud enough to scare inexperienced pilots. Does this means he doesnt experience aileron snatch as well? Very interesting. The loud bang may be attributed to the swivel arm design of the E/F models, since G/K models used a roller track mechanism. Nice read right here. http://109lair.hobbyvista.com/techref/systems/control/slats/slats.htm

Until the slats themselves stall you should have air rerouted above the wing, airflow attached and therefore some amount of lift induced. This holds true for both normal and accelerated stall. Furthermore there should be aileron authority until airflow has completely seperated from the control surfaces and some aileron authority on the downward pointing aileron right up until complete stall, correct? So in a power off situation the wing root stalls before the outwars wing section, inducing drag and diminishing lift but aileron authority remains good since the slats increase critical AOA. Now in a power on situation the wing root is energized by the prop wash increasing critical angle of attack. The slats keep the airflow attached to the aileron section. That is favorable and even necessary since AFAIK the 109 wing did indeed not have any wing washout. Since the prop is turning clockwise in a 109, the prop wash is directed downwards on the right wing side. This means right wing root will stall after the left wing root. This in turn would lead to asymmetrical wing stall and therefore wing drop to the left side. (torque coming into play as well) Now if slats were indeed effective enough to keep the ailerons from stalling up until power on root stall the wing drop effect would be very benign and easily controllable. I dont know if there are any reliable documents around about critical angle of attack on wing root (power on) and for the slats, but the stall behavior at the moment seems indeed a bit vicious if I think about it. In an power on stall the wing drop is aprupt and not very controllable atm. The pre stall buffeting on the other hand is well done Id say. If I may pass a question directly to YoYo here, is the stall behavior hard coded or aerodynamically calculated? The few pilot notes available mention a very benign stall which is easily rocoverable with no spin preference observable. In the sim i cant see a spin preference, so that is also well modeled. Edit: Just want to add this statement. The relevancy is questionable since its about the E model, but tendency should be similar.

Finnish pilots at least described flutter not to happen up until very high speeds. Here are two examples. I guess the rotating part of the second Interview is well modeled, since you cant compensate roll in very high speed dives with ailerons/rudder anymore. Me 109 G: "-Someone asked of the top speed of the Me. Mr Väinö Pokela told earlier it's 720 km/h, when I interviewed him. Normally we flew the Me at 500 km/h, but at a tough spot we could go some 600 km/h. But the absolute speed limit is found in dive. I had to do some over 900 km/h dives. The speedometer scale ends at 900, and at that you feel the flutter effect in the wings. Guess it was very near the top speed, when the plane felt like falling apart." - Edvald Estama, Finnish fighter pilot. Source: Recollections by Eino and Edvald Estama by Finnish Virtual Pilots Association. Me 109 G: "The maximum speed not to be exceeded was 750kmh. Once I was flying above Helsinki as I received a report of Russkies in the South. There was a big Cumulus cloud on my way there but I decided to fly right through. I centered the controls and then something extraordinary happened. I must have involuntarily entered into half-roll and dive. The planes had individual handling characteristics; even though I held the turning indicator in the middle, the plane kept going faster and faster, I pulled the stick, yet the plane went into an ever steeper dive. In the same time she started rotating, and I came out of the cloud with less than one kilometer of altitude. I started pulling the stick, nothing happened, I checked the speed, it was about 850kmh. I tried to recover the plane but the stick was as if locked and nothing happened. I broke into a sweat of agony: now I am going into the sea and cannot help it. I pulled with both hands, groaning and by and by she started recovering, she recovered more, I pulled and pulled, but the surface of the sea approached, I thought I was going to crash. I kept pulling until I saw that I had survived. The distance between me and the sea may have been five meters. I pulled up and found myself on the coast of Estonia. If I in that situation had used the vertical trim the wings would have been broken off. A minimal trim movement has a strong effect on wings when the speed limit has been exceded. I had 100kmh overspeed! It was out of all limits. The Messerschmitt's wings were fastened with two bolts. When I saw the construction I had thought that they are strong enough but in this case I was thinking, when are they going to break - What about the phenomenon called "buffeting" or vibration, was there any? No, I did not encounter it even in the 850kmh speed." - Kyösti Karhila, Finnish fighter ace. 32 victories. Source: Interview by Finnish Virtual Pilots Association.

So I came to think about it and actually would like to see a G-10. It will still not fit the mid 1944 timeframe, but it would be a nice addition. Flight model wise it wouldnt pose much of a problem since at the moment we basically have a G-10. A slight adjustment to weight and voila, there is a G-10. It wouldnt be an ERLA G-10 since these were significantly lighter and didnt carry all the heavy equipment. War time pilots mentioned it was the only 109 you could reliably hit above 700 km/h with, including K models (probably due to consistent production quality). The visual model however would need some adjustments. Namely DF radio loop placement, radio hatch position, antenna wire (mast), wheel covers & fixed tailwheel. The cockpit would also need an overhowl. The instrument panel for example, but no different instruments were used and only repositioning is needed. Now the switchboard looks somewhat different and pretty much the whole right side of cockpit. I think the main expenditure here would be the cockpit. Everything else is easily done Id say. What do you guys think? I linked some exterior/ cockpit pics of remaining original wartime G-10s for comparison. http://www.nationalmuseum.af.mil/Visit/MuseumExhibits/FactSheets/Display/tabid/509/Article/196264/messerschmitt-bf-109g-10.aspx http://www.airspacemag.com/panoramas/messerschmitt-bf-109g-10-180947945/?no-ist http://www.globetrotter-fotos.de/technik/luftfahrt/luftfahrtmuseen/planes-of-fame.html

Well you are right. There is no way to prove it, it seems very likely though. ERLA built high performance G10/K4 and other factories just slapped parts together as supplies allowed, making MG 151s in K4s probable. I agree with you though. I just would really like to see a 151 in a K4 i guess.. :cry:

I fail to see how a G10 for example would fit that timeframe any better. You would need a G14 with just about different everything to fit in. To name a few: different wing bulges, wheels, sporn, antennas, many systems, most likely different cowling, motor, prop, rudder... As far as I remember there were 109 K4 ERLA production batches with MG 151/20 installed. I think thats how it was mentioned in Jochen Priens book? Dont remember exactly.. found something on that: http://forums.eagle.ru/showpost.php?p=2196174&postcount=306

On a sidenote, IIRC ERLA G10s also used a "newer generation" engine cowling, designed with larger oil cooler and without the blisters, which was initially planned for higher number K models. Im not sufficiently sure about the story though. Given the similarity I dont think the changes necessary would justify a late G model. Especially not, when looking at the competition. I dont think anyone online would choose a higher drag G10/G14 over the faster/ better climbing K4 to be honest. It almost looks the same anyway.. What I would really like to see however is the MG 151/20 instead of the MK 108 in the prop hub. That would in my opionion be a nice and easy addition which would see a lot of use. After all it has been already completely modeled for the Dora. Historically speaking it is also completely in line, since MK 108 and MG 151 were pretty much randomly put into planes because of difficulties in supply. :) What I would very much love to see is an F4 or G2 which is modeled to standard (unlike what is presented in BOS for example). That however basically would need a completely new design process. :(

Alright I think ArkRoyal has a point. Although I cannot reproduce a figure of 25 m/s I consistently measure 23.8 m/s (6 different testruns) climbrate with rads at 2/3rds, 1.8 ATA MW50 engaged between 1000 m and 2000 m altitude. I started several times at 1000 m and 1500 m and measured the time for 500m climb, when starting at 1000 m I also measured the time to 2000 m. Ball was centered, speed 300 +-5 km/h. For 500 m to 1000 m I measured consistenly somewhere in between 20-21 s. That would roughly equate to 24.4 m/s climbrate. These are all handtaken ballbark figures and no exact science, but interesting nontheless. Since I am done packing up my stuff I can test some more tonight. Tomorrow I will leave for vacation anyway. :) Edit: Thanks javelina1 for your efforts. Try making a mission with standard parameters no weather effects, air start, fuel and ammo at 100% and start off at sea level. Then setting the radiators to be just about parallel (=~2/3rds open), bleed off excess speed and go on from there with the desired ATA setting. Good luck!

Yes I simply calculated average climb rates. Can you tell me at which altitude it is overclimbing by 2,5 m/s? Tomorrow I will then test on said altitude in more detail. I sadly dont own TacView. Edit: Sorry I misread your post. I will test from 0 - 7000ft.

Last test for today: rads 2/3rds open 499s -> avg. to 7500m 15 m/s Actually I cant confirm that atm. Took me 8 min 19 s to 7500m with rads 2/3rds open. The chart would suggest 7200m altitude. Others may fly smoother and therefore climb better than I do, but in my last test at 1.45 ATA the K4 seems to overclimb only marginally compared to the chart.

If I read correctly the time estimation is for 1.45 ATA Steig und Kampfleistung. I just tested 4 times with 1.8 ATA + MW50 Sondernotleistung, starting at approx. 20 m above MSL, ending 7500m MSL, 100% fuel & ammo, starting speed ~300 km/h, 20° C temperature and no weather effects set on the map. I measured twice with rads set to auto and twice with rads fully open. rads auto: 347s, 345s -> 21.6 m/s rads fully open: 383s, 382s -> 19.6 m/s I tried to keep it in the speed range of 270-280 km/h and the ball always centered. I also just tested once 1.45 ATA, rads fully open, everything else exactly as above. 550s -> 13.6 m/s That corresponds pretty well to the graph. The data shown on the graph give a heigth estimation of about 7700-7800m after 550s climb time. Keep in mind though I used fully opened rads, started at ~300 km/h and I cant tell if the normal or the thin blade prop were used for this graph. Im very interested in other results. I would not yet draw conclusions with my tests alone Edit: Sometimes Im just stupid.. The props perform the same until FTH is reached, that is why I measured to 7500m in the first place.

Thats quite reasonable, but as YoYo said earlier the flat area drag for main wheel covers match other (I think soviet?) sources well, so I would argue the others to be correct as well. Somewhere I have seen a level flight test which included the tailwheel, but I cannot for the life of me find it anywhere... Edit: Didnt he post the original document to the transcript?

I think it comes down to if or if not YoYo accepts the data presented by Kurfürst as viable. As I understood it he already acknowleged our concerns about the drag difference between G and K models. I think it is in our all interest to model an as close to real life 109 as we (well actually YoYo :thumbup:) can. I would argue the data is legit, since it says Leistungsmessung "Messung" = measurement, so I would guess german engineers to be competent enough to measure flat area drag correctly. Now that this is just my humble assessment which noone cares for im totally aware! :smilewink:

I think you misinterpreted what I said. Lets take it to an extreme and say our 109 flys at 800 km/h levelflight MSL and the P51 model has a maxspeed which would relative to these 800 km/h be perfectly correct. That would make them balance wise still perfectly viable, but it doesnt change the fact speedvalues per se are historically incorrect. Just an example. That there is a variance in factory model performance is perfectly correct and normal. But why use >2% deviaton of mean to the worse when german documentation shows random sample analysis of production line aircraft to be well within mean. (That is for G models at least.) Do you know what Im trying to say?

Well if Kurfürst says he has pictures of this test run, I would say that could be used as proof?

The MSL speed atm is roughly at the level of a higher drag late G14, so it it somewhat slower than depicted in the charts. That may be due to drag modeling of parts which where actually aerodynamically improved in the K4 model. Main focus being on retracted tailwheel, wheel covers, (possibly engine hood) and resulting reduction in drag.