"Kit" analyses 109 and 190

[illo]

I decided to post some reading for you  
I hope you all havent read this before.


 

The Best of the Breed
Airpower, July, 1976 Vol. 6 No. 4
by Col. "Kit" Cars

General Characteristics


Me-109


The characteristics of two Me-109 models are of historical interest, the "E" and the "G". The "E" formed the backbone of the German fighter strength during the Battle of Britain, its opposition being the Spitfire I and the Hurricane I. The "G" was the prevailing type in 1944 during the Battle of Europe and its main opponents were the Spit Fourteen, the Thunderbolt, and the Mustang. So it is worthwhile to explore more fully the characteristics of the Me-109 because it was the longest lived of the fighters produced in Germany and it was a most worthy opponent in 1939 it was outclassed by 1942; by 1944 was manifestly obsolete.


An intact Me-109E with wing cannon was captured by the French in the summer of 1940 and was flown to England for flight test and evaluation. There were three stages of development prior to the "G". First was an early version of 109 flying in 1938 with a 670hp Jumo 210 engine, a fixed pitch wooden prop and two synchronized guns. Second was the variable pitch two-bladed prop model and the addition of two wing guns. Third was the "E" model, with a far more powerful engine, the DB601, which was an inverted V-12 of 1100hp with direct fuel injection driving a 3-bladed variable pitch prop. Its wing structure was beefed up but in the process of "designing" in the additonal engine and structural weight, the engineers screwed up  the center of gravity, and 60 pounds of permanent ballast had to be added to the rear of the fuselage to get the C.G. back. As a pilot and an engineer I can only be sympathetic with 109 pilots. Who needs that kind of milstone around his neck in a fighter? Pilots had nothing to say about the design faults of airplanes in Germany. They had damn little to say about them in England or in this country, at that time. Designers didn't have to fly their mistakes; they just produced them. Most of them didn't know how to fly and didn't want to learn, but more about that later.


In size the Me-109, all models, was the smallest fighter produced by Germany or the Allies. That gave it a high wing loading for that time, about 32 lb./sq. ft. for the "E". The Spit I and the Hurricane I were about 25 lb./sq. ft. at their normal combat weight. The 109-G was about 38 lb./sq. ft. as compared to 35 lb./sq. ft. for the P-51B.


            ME-109E      ME-109G
Mean weight lbs.      5580         6450
Engine            DB 601         DB 605A
Horsepower         1100/15,000 ft.      1475/22,000 ft.
Power loading, lbs./HP      5.07         4.37
Wing loading, lbs./sq. ft.   32.1         37.5
Prop. diameter, ft.      10.2         9.83
Gear Ratio         14/9         16.85/10


Wing Geometry:


Area sq. ft.         174         172
Span, ft.         32.4         32.6
Mean Chord, ft.         5.36         5.38
Aspect Ratio         6.05         6.10
Dihedral, degrees      5.75         5.75
Sweepback, degrees      1.0         1.0
Root chord, ft.         7.03         7.0
Tip chord, ft.         3.42         3.42
Root thickness, percent chord   14.8         14.2
Tip thickness, percent chord   10.5         11.3
Slat length/span, percent   46.2         Approx. same
Slat Chord/local chord, percent   11.8         Approx. same
Wing Twist, Root to tip      0         0


Speed, mph         354/12,500 ft.      387/23,000 ft.


The fastest "G" subtype was the G-10 capable of 344 mph at SL or 428 mph at 24,000 ft. with a meager range of 350 miles and an endurance of 55 minutes, but it wasn't introduced until the spring of 1944. Too little, too late, and still lacking in rnage and endurance.


Engine and Propellor


In principle the DB601 and 605 series engines were the same as the Allison or Merlin, except they were inverted and had direct fuel injection; otherwise they were 12-cylinder, 60 degree Vee, glycol cooled engines. The prop was a 10.2 foot, 3 blade variable pitch mechanism of VDM design. here is another major difference between their design approach and ours. The pitch on the Me-109 prop could be set at any value between 22.5 and 90 degrees, a visual pitch indicator being provided for the pilot. There was no provision for automatically governing the rpm. We did just the opposite, using a constant speed governor and flying by a constant tachometer indication of rpm. For any flight condition the rpm remained constant. We did know, or care, what the blade angle was.


Wings and Controls


The wings had straight leading and trailing edge taper and no geometric twist from root to tip. The airfoil section had a 2 percent camber with the maximum thickness at the 30% chord position. The "E" thickness ratio was 14.8 percent at the root and 10.5 percent at the tip. All that was standard design practice of the mid-1930s. What was new for fighter design was the leading edge slats which ran 46% of the span. There was no damping device fitted t the slat mechanism, they'd bang open at 120 mph with the airplane clean or at 100 mph with the gear and flaps down. Each control surface was mass balanced. Another unusual feature was that as the flaps were lowered, the ailerons automatically drooped, coming down 11 degrees for the full flap movement of 42 degrees.


There were no movable trim tab controls on the ailerons or rudder, although both had fixed tabs that could be bent on the ground. Pitch trim was affected by changing the stabilizer incidence thrugh a range of 12 degrees. The design scheme was that both the flaps and the stabilizer were coordinated mechanically from two 12 inch wheels mounted concentrically on the left side of the pilot's seat. By twirling both wheels in the same direction the pilot could automatically compensate for the change of pitch trim due to lowering or raising the flaps. Differential coordination could be set by moving one wheel relative to the other.


Performance Evaluation


The first surprise you get in planning a test hop in the Me-109 is that you're limited to about an hour with some aerobatics at combat power, because the internal fuel capacity is only 88 gallons; with the drop tank, the "G" carried a total of 154 gallons. I'll never understand why the fuel capacity designed in Luftwaffe fighters was so limited. It was a major design deficiency that contributed to the los of the air war, but even more puzzling is the fact that it could have been quickly changed anytime after 1940 onward, but it wasn't.


Takeoff was best done with 30 degrees of flaps. The throttle could be opened quickly without loading or choking up the engine. In fact, the Daimler-Benz engine was the best thing about that airplane. The stick had to be held hard forward to get the tail up, and it was advisable to let the airplane fly itself off. If it was pulled off at low speed the left wing would not respond and on applying aileron the wing would lift and fall again with the aileron snatching a little. If no attempt was made to pull it off quickly, the takeoff run was short and the initial climb good.


The absense of a rudder trim control in the cockpit was a bad feature at speeds above cruise  or in dives. Above 300 mph the pilot needed a very heavy foot on the port rudder pedal for trimmed flight with no sideslip which is absolutely essential for gunnery. The pilot's left leg quickly tired while keeping this load on, and this affected his ability to put on more left rudder for a turn at 300 mph or above. Consequently, at high speeds the 109 could turn far more readily to the right than to the left.


Fighting Qualities


A series of mock dogfights were conducted by the British in addition to the flight test and the following was revealed:


If the airplane was trimmed for level flight, a heavy push on the stick was needed to hold it in a dive at 400 mph. If it was trimmed into the dive, recovery was difficult unless the trim wheel was wound back, due to the excessive heaviness of the elevator forces.


Ailerons


At low speeds, the ailerons control was good, response brisk. As speed increased the ailerons became too heavy but the response was good up to 200 mph and 300 mph they became "unpleasant". Over 300 mph they became impossible. At 400 mph the stick felt like it was set in a bucket of cement. A pilot exerting all his strength could not apply more than one fifth aileron at 400 mph; that's 5 degrees up and 3 degrees down. The aileron situation at high combat speeds might be summarized in the following way:


   (1) Due to the cramped cockpit a pilot could only apply about 40 pounds side force on
        the stick as compared to 60 pounds or more possible if he had more elbow room.


   (2) Messerschmitt also penalized the pilot by designing in an unsually small stick top            travel of plus or minus 4 inches, giving very poor mechanical advantage between pilot         and aileron.


   (3) At 400 mph with 40 pounds side force and only one fifth aileron displaced, it required         4 seconds to get into a 45 degree roll or bank. That immediately classifies the            airplane as being unmaneuverable and unacceptable as a fighter.


Elevator


This was a good control at slow speeds but became too heavy above 250 mph and at 400 mph it became so heavy that maneurverability became seriously restricted. When diving at 400 mph a pilot, pulling very hard could not pull enough "g" force to to black himself out. The stick force per "g" was an excess of 20 pounds in a high speed dive. To black out, as a limit to the human factor in high speed maneuvers, would require over 100 pounds pull on the stick.


Rudder


At low speeds the rudder was light but sluggish in response. At 200 mph the suggishness disappears, at 300 mph the absense of trim control in the cockpit became an acute problem. The pilot's leg force on the port rudder above 300 mph to prevent sideslip became excessive and unacceptable.


Control Harmony


At low speed, below 250 mph, control harmony was good, only a little spoiled by the suggishness of the rudder. At higher speeds the aileron and elevator forces were so high that the word "harmony" is inappropriate.


Aerobatics


Not easy to do. Loops had to be started from about 280 mph when the elevator forces were getting unduly heavy; there was also a tendency for the wing slats to bang open the top of the loop, resulting in aileron snatch and loss of direction.


Below 250 mph the airplane would roll quickly but there was a strong tendency for the nose to fall through the horizon in the last half of the roll and the stick had to be moved well back to keep the nose up.


Upward rolls were difficult, again because of elevator heaviness at the required starting speed. Due to this, only a moderate pull out from a dive to build up speed was possible and considerable speed was lost before the upward roll could be started.


The very bad maneuverability at high speed of the Me-109 quickly became known to the RAF pilots in 1940. On many occasions 109 pilots were led to self destruction when on the tail of a Hurricane or Spitfire at moderate or low altitudes. The RAF pilot would do a snappy half roll and "split ess" pull out, from say 3,000 feet. In the heat and confusion of the moment the 109 pilot would follow, only to discover that he didn't have enough altitude to recover due to his heavy elevator forces and go straight into the ground or the Channel without a shot being fired.


Turning Radius


At full throttle, at 12,000 feet, the minimum turning radius without loss of altitude was about 890 feet for the Me-109E with its wing loading of 32 pounds per square foot. The corresponding figure for the Spit I or Hurricane was about 690 feet with a wing loading of 25 pounds.


Summary


Good points:
   (1) Reasonable top speed and good rate of climb.
   (2) Engine did not cut out under negative "g," also reliable.
   (3) Good control response at low speeds.
   (4) Easy stall, not precipitous.
Bad Points:
   (1) Ailerons and elevator far too heavy at high speed.
   (2) Poor turning radius.
   (3) Absence of rudder trim control in cockpit.
   (4) Aileron snatch (grabbing -- uneven airflow) when slats opened.
   (5) Cockpit too cramped.
   (6) Visibility poor from cockpit.
   (7) Range and endurance inadequate.


While the 109 may have been a worthy opponent in the Spanish Civil War or during the Battle of France in early 1940, it became a marginal airplane against the Spits during the attack on Britain in September of that year. By 1942, even with the appearance of the "G," it was definitely obsolete. However, the Germans continued to produce it as the backbone of the Luftwaffe fighter forces. The attitude of Nazi high command was that this was going to be a quick "blitz" war and if they lost three 109s for every Spitfire shot down, that was acceptable. In fact, in 1940 the official policy was laid down that the development of all other aircraft types requiring more than 6 months for completion was prohibited. They'd turn out the existing designs like hot cakes and swamp the RAF with production.


That doesn't say much for any charitable concern they should have had for the unnecessary loss of pilots cause by going into combat with a substandard airplane. But, after all, no one has ever said that the Fuehrer and Goering had any anxiety about their pilots or troops. Quite the contrary, the record of history shows that they had none.


Furthermore, no designer in that period would pretend that he could stretch the combat effectiveness of a fighter for 7 years, 1935 to 1942, without major changes in power plant or aerodynamics, or, better yet, going to a new design. Technology in design in that era was changing too fast. The reader might well say, "The Spitfire was certainly a long line of fighters, about 10 years, how come?"


The Spitfire was an aerodynamically clean airplane to start with, having a total drag coefficient of .021 at cruise. The Me-109 had a coefficient of .036; drag coefficiency and of the horsepower required to haul 'em around. Like golf scores, the lower the better, and no fudging.


The British, in particular the staff at Vickers Supermarine, had done their homework in aerodynamics and put out a clean airplane that had the potential of longevity and increased performance. They had only to wait for Rolls-Royce to pump up the horsepower on the Merlin, which they did by going from 790 hp in 1934 to well over 2,000 by 1945. The Merlin, in my (Col. Carson's) opinion, was the best achievement in mechanical engineering in the first half of the century.


Messerschmitt practically ignored the subject of low drag aerodynamics and one can tell that by an inspection of the 109E or G. The fact is evident even in close-up photographs. It was aerodynamically the most inefficient fighter of its time. That's a puzzling thing when one realizes that much of the original work on high speed drag and turbulent surface friction was done in Germany in the 20s and 30s. Messerschmitt was surrounded by it. Further, the work in England and the U.S. in thiss field was in the open literature, at least until 1938.


I also suspect, again from the record of history, that Willy Messerschmitt was too busy becoming a Direktor of Messerschmitt A.G. to concentrate on improving his status as an ingenieur.


Having gone this far, let me carry this affront to Messerschmitt's engineering reputation one step further.


An airplane factory can get things done awfully fast, in any country and in any language, once the engineers and sheet metal benders understand what is wanted. Every factory has a "development shop" or its equivalent, which is a full scale model or prototype shop with 100 or 200 old pros in every skill. Having that many coffee drinkers, pipe smokers and "yarn spinners" around on the payroll, let's clobber 'em with a bundle of shop drawings on a clean up of the Me-109. Object: to make it a 400 mph plus airplane. Time...30 days. The information and techniques required are currently available as of 1940. It's all written up in unclassifed reports.


   (1) Cancel the camouflage paint and go to smooth bare metal. Besides the weight,            about 50 pounds, the grain size is too large when it dries and it causes turbulent            friction over the entire airplane surface. That may take a phone call to the brass.            They're emotional about paint jobs. "Image,"  you know.
   (2) Modify the cockpit canopy. Remove the inverted bathtub that's on there now and            modify as necessary to fit the Me-209-VI canopy. That's the airplane that set the            world speed record in 1939.
   (3) Get rid of the wing slats. Lock them closed and hand fit a strip, upper and lower            surface, that will close the sheet metal gaps between the slat and wing structure.            That gap causes the outboard 15 feet of each wing to be totally turbulent.
   (4) As aerodynamic compensation for locking the slats, setup jigs and fixtures on the            assembly line to put in 2 degrees of geometric twist from the root to tip, known as            "washout."
   (5) Modify coolant scoop inlet fairings. The square corners that are there now induce an            unnecessary amount of drag. Also lower the inlet 1 to 2 inches below wing surface to         get it out of the turbulence of the wing surface.
   (6) Install complete wheel well farings that cover the openings after the gear is retracted.
   (7) Retract tail wheel.


All of the above could have been done in 30 days but it wasn't. I don't know why. Someone would have to ask Willy...it's for him to say.

Not very favorable comments  


[This message has been edited by illo (edited 04-26-2001).]

[illo]

And now FW 190. In whole different tone  


 

Airpower, July, 1976 Vol. 6 No. 4
by Col. "Kit" Carson


Part 2 (continued)


General Characteristics


FW-190A


A superb airplane, every inch a fighter. It could do a half roll at cruising speed in one second. Taking this in conjunction with the airplane's high top speed and rate of climb one expected its pilots to exploit its high speed qualities to the fullest without staying in there to "mix it up" in a low speed, flaps down full throttle, gut wrenching dog fight.


They did. The 190 pilots had a good airplane and some good advice. Nearly all of my encounters with the 190 were at high speeds. On at least two occasions when I met them, in my Mustang started porposing, which means I was into compressibility, probably around 550 mph. I don't know what my air speed indicator was reading, I wasn't watching it.


On another occasion, I jumped one directly over the city of Paris and fired all my ammo, but he was only smoking heavily after a long chase over the town. Assuming I was getting 10 percent hits, that airplane must have had 200 holes in it. It was a rugged machine.


   Mean weight         8580
   Engine            BMW 801D
   Horsepower         1600
   Power loading, lbs./HP      5.36
   Wing loading, lbs./sq.ft.      41.7
   Prop diameter, ft.      10.86
   Wing Geometry
   Area, sq.ft.         205
   Span, ft.         34.5
   Mean chord, ft.         5.95
   Aspect Ratio         5.8
   Dihedral, degrees      5
   Sweepback, degrees      5.5
   Root chord, ft.         7.45
   Tip chord, ft.         4.05
   Thickness Ratio, percent   12
   Maximum thickness location   Between 25 and 30 percent
   Top speed, mph      408/20,600 ft.


Engine and Propeller


The BMW 801D was a 14 cylinder, twin row radial with direct fuel injection. A 10.9 foot diameter, 3-bladed VDM prop was used and was provided with hand lever or automatic pitch control. The 801D radial air cooled engine first appeared on the Dornier 217 and the Fw-190. Its most novel feature was the oil cooler system which was a number of finned tubes shaped into a ring of tubes a little larger in diameter than the cooling fan. This ring was fitted into the rounded front portion of the cowling just aft of the fan.


I don't think this was a good idea. For example, my principal aiming point was always the forward portion of an enemy ship; the engine, cockpit, wing root section. If you get any hits at all, even only a few, you're bound to put one or two slugs into the engine compartment. Having a couple of bullets riccochet off the engine block and tear up some ignition harness is not too bad at all, at least not fatal. But to have all those thin-walled oil cooling tubes ahead of the engine is bad news. Any hits or riccochets in the engine section are bound to puncture the oil tubes. Then the whole engine is immersed in oil spray, and sometimes it would flash over into a fire. All of the 12 Focke-Wulfs that I shot down sent off a trail of dense, boiling oil smoke heavy enough to fog up my gun camera lens and windshield if I were so close.


Wings and Controls


Again, as in the case of the Me-109, no trim tabs adjustable in flight from the cockpit were provided for the aileron and rudder. European designers seem to have acquired the notion that this was a nuisance or unnecessary. Not at all; when going into a dive, it's very easy for the pilot to reach down with his left hand and flick in a couple of half turns of rudder trim. It's not only desireable but necessary to eliminate side slip for good gunnery. The Fw-190, however, did have electric trim tabs for the elevators.


Performance Evaluation


The Fw-190's handling qualities were generally excellent. The most impressive feature was the aileron control at high speeds. Stick force per "g" was about 9 pounds upto 300 mph rising to 12 pounds at 400 mph as compared to over 20 pounds for the Me-109.


High speed stalls under "g" load were a little vicious and could be a fatal handicap in combat. If the airplane was pulled in tight and stalled at high speed at 2 "gs"  or more with the power on, turning right or left, the left wing would drop violently without warning and the airplane would flick onto its back from a left turn. I scored against a 190 under such circumstances. The message was clear, don't stall it. Our own Bell Aircobra P-39 would do the same thing.


Fighting Qualities


Excellent high speed, with exceptional maneuverability at those speeds. Range and endurance were markedly improved over the 109. The Focke-Wulf would go 3 hours plus. Visibility with the full view canopy was superb, as it was in the Mustang.


Summary


Bad points:
   (1) Oil cooling tubes at the front of the engines was a poor choice of location. A puncture         due to combat damage, or to simple failure covered the engine section with an oil            spray.
   (2) Lack of aileron and rudder trim controls in the cockpit.
   (3) Vicious high speed snap rolls if stalled under significant "g" load.
   (4) Poor turning radius due to high wing loading.


Good points:


Everything else was good. In the hands of a competent pilot the 190 was a formidable opponent. The landing approach speed was high and this shakes some pilots up a bit, but I don't think it's anything it's anything to complain about.

Heh... ever heard of AH 190 taking 200x.50cal rounds resulting only smoking engine?




[This message has been edited by illo (edited 04-26-2001).]

[Sturm]

This will be a locked thread soon    As I see it now the 190 and 109 are about the same in damage absorbed.  I wonder if we can get a earlier model of the 190?  A-1's thru A-4 were actually nice turners, more so then the later models.  

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[janjan]

Smoking 190s? When? where?

Oh in AH...Happened me twice since beta.

[BlauK]

Nice analyses  

Just noticed that the old "common knowledge" mistake of the speed of 109G has creapt into this writing as well.

The max speed of 387 concerns only the gunpod version (109G-6/R6).

Plain 109G-6 had a top speed of 397-398 mph.

I wish a lot of authors (book makers) would stop repeating this mistake and check for reliable sources. Many just rely on the numbers on Spick's books and spread the mistake around  

[Pepe]

Thks for the post Illo. Very illustrative, and nice reading.

Cheers,

Pepe

[Sturm]

Blauk look at the D-9 top speed exact same one you will see posted in all the books.  Even though it would hit 440 and sometimes higher depending on if engine was revved a bit    I don't have the charts but it clearly shows 426 was not the top speed of the D-9.  Someone out there has them I think Naudet might still have them.  I lost them when machine died on me  

[juzz]

Uhm, some really good ideas there, not!

1. Cancel camo paint, so that Allied fighter bombers can find 109 airfields by the shimmering metal reflections - ever seen all those natural metal US fighters with paint on the upper surfaces - that's all about "image" I suppose?!

2. Modify cockpit canopy to a low-drag, and super-low-visibility design from the world speed record holding race plane.

3. Remove wing slats so that low-speed control and stall behaviour is dangerously poor.

4. Then arbitrarily apply 2º of geometric twist with absolutely NO IDEA of exactly how that will affect the handling characteristics of the plane, let alone the integrity of the wing structure.

5. Ruin the perfectly good boundary layer diversion system of the wing coolers for a more conventional and "obvious" design.

6. They finally did that on the K.
7. See above, plus F model too.

[LLv34_Camouflage]

Thanks, Illo!  

Camo

------------------
Camouflage
XO, Lentolaivue 34
 www.muodos.fi/LLv34

Brewster into AH!

"The really good pilots use their superior judgement to keep them out of situations
where they might be required to demonstrate their superior skill."

[illo]

Righty right, juzz

[hazed-]

great posts.

ok now ive seen this I'll stop complaining about always seeming to get engine hits in 190's  
I'll stop wondering if AH has a realistic 109 in it! lol all those bad traits are here in AH  

Can someone put his views on p51's and any other aircraft from WW2?
this col 'kit' guy im beginning to like  


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Hazed
3./JG2

[This message has been edited by hazed- (edited 04-26-2001).]

[jato757]

lotsa good info  

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[Sorrow[S=A]]

Yes- some points made Juzz,

Also- Bare metal finish- not going to happen- EVER.

the finish on 109's sufferred horribly from degredation of irregularities in the metal if left exposed. The material literally corrodes away leaving very weak remanents.

Without a proper primer and paint that plane is going to rot out from under you.

American planes sufferred from this too BTW as well as Japanese ones. Only pure Aluminum like the stuff used on the P-51 was safe from it.

Juzz pointed out the obvious about the slats- what bloody good is a plane that does 400 mph but cannot be safely flown at low speeds?

Oh- BTW quit making cracks on the Yak, it was a rushed development that covered allot between 1940 and 1945. And by the 9U the development had surpassed the 109 in aerodynamics. Hell- they learned how important the finish was on the 109 by studying how the Yak had such a bizarre low drag than they expected.

[DB603]

S!

 Thanx for the post illo.Looks like another 109-bash tho  Still gonna fly it against the "perfect" Allied iron  



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DB603
3.Lentue
Lentolaivue 34

[Flitze]

It reads like the 109 was totally unusable as a fighter. Sure it was outdated compared to the Mustang (e.g. 80..90 kph difference with very similar engine power), but the differences of the planes were obviously not as decisive as the differences of the pilot's experience and skill, especially when the numbers are taken into account.