improving the 109??

[bobbysocks]

I ran across an article that reposted a blurb from Leonard "Kit" Carson's 1976 interview or story in Airpower magazine. in it he proposes several mods to the 109 to "clean up the airframe" and get more performance out of the plane. How practical or realistic were these proposals? Carson worked for the aerospace industry but at what capacity I do not know.. here's what he says:

"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 this 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 unclassified 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 fairings that cover the openings after the gear is retracted.

(7) Retract tail wheel. (Tom's Note: This was actually done on some models of the 109.)

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."

 

[Hickam Field]

Good topic,
I've heard some of those before and some of those improvements were placed into application at one point or another. Just not in effective time or quantity. One of the previous threads from many moons ago (think it was Erich) mentioned sanding down and wax coating operational G-14s or -10s enabling them a better chance of catching Mosquitoes. K-4s had a retractable tail wheel....
From what I've read about Messerschmitt, the 109 was personally a past success for him from 1942 onwards. By that point, it sounds like he was creatively on to more ambitious projects like the Me-262, "Amerika Bomber," and several others.
I agree entirely. The 109 could've been improved further with some simple adjustments like the ones you listed above.

 

[Capt. Vick]

Drawing on my dusty memories from college aerodynamics, the turbulence that you state as being on the outboard 15 ft (?) of the main wing may have (depending on its severity) actually made the ailerons more effective.

 

[Shortround6]

Some of the suggestions are good, some not so good.

Doing away with camouflage paint works real good when you dominate your enemy to the point where he seldom flies over your airfields. Getting blown up on the ground means it doesn't matter how fast you go in the air. It is not about image, it is about getting strafed while on the ground.

Not sure on the Me 209 canopy.

Some better but hardly a real game changer.

Doing away with slats and substituting washout may be almost an even trade in regards to drag. Reducing overall lift of the wing may not be the best idea for late model 109s.

Quite a few of the 109Fs and Gs already used a retracting tail wheel or at least semi-retracting.

Tail wheel retracted into the notch above/behind. Later 109s fitted larger wheels and/or longer struts and lost the retract. They also gained lumps and bumps over the large cowl machine guns and over the wheel wells on the wings to fit larger tires. The Fs were probably the most aerodynamic.

 

[GrauGeist]

I ran across an article that reposted a blurb from Leonard "Kit" Carson's 1976 interview or story in Airpower magazine. in it he proposes several mods to the 109 to "clean up the airframe" and get more performance out of the plane. How practical or realistic were these proposals? Carson worked for the aerospace industry but at what capacity I do not know.. here's what he says:

"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 this 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.

Not so...when the Bf109 was first introduced in the 1930's, it was one of the fastest warplanes on earth.

It was also designed around 1930's technology. What we know now is lightyears beyond what they knew at the time. As it happens, as time progressed, the Bf109's airframe had to adapt to the rapidly changing environment and it managed to keep pace with the best that the Allies had to throw against it right to the end of the war - on an airframe design that was over a decade old.

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 unclassified reports.

As soon as they said "30 days", I lost interest. In a wargame simulation or a fantasy book series, this is doable, but in real life, it takes months if not years to redesign, test, retool and start production.

(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.

Not image - survival
The Germans were masters of camouflage and if they had bright, shiny aircraft, then all the easier for them to be hunted down and killed. Only in an Air-Superiority environment, do you have the luxury of shiny things.

(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.

Later Bf109 variants had an improved canopy, but to put a Me209/Me309/Me262 style canopy on the Bf109 would have meant considerable change to the fuselage.

(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.

The slats were there for a reason and they made the Bf109 extremely deadly in a turning fight. Eliminating the slats defeats one of the main performance features of the Bf109.

If they took the time to learn and understand how slats work, they would know that the slats, fully retracted, are not "totally turbulant", Dude. Like, Way.

(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."

I would LOVE to see the look on an Aeronautical Engineer's face when they read this part...

(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.

There may have been some features that induced penalties on the Bf109, but the cooling surface area on the Bf109 was critical. It was introduced to the airflow with a specific formula. There's a great many photos of the Bf109 in a wind tunnel to show how Willy dealt with these issues.

(6) Install complete wheel well fairings that cover the openings after the gear is retracted.

Additional weight and mechanisms - would the penalty be worth the gain?

(7) Retract tail wheel. (Tom's Note: This was actually done on some models of the 109.)

Yes, it was done on some models...

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."

Again, this comment of theirs is deep in the fantasy realm

Want to see what a Bf109 looks like after it has had all the aerodynamic issues addressed?

 

[stona]

Eliminating the slats may or may not improve combat performance, only the most experienced pilots push an aircraft close to its limits at which point they might make a difference, but it will certainly kill a lot more inexperienced pilots by increasing the aircraft's accident rate. Poorer performance near the ground and higher landing speeds tend to do that.
They were an aerodynamic design feature of the aircraft, they were deleted from the Me 210 as a matter of expedience and this definitely contributed to the problems with that aircraft. Unsurprisingly, they were restored on the Me 410.
Cheers
Steve

 

[GrauGeist]

Eliminating the slats may or may not improve combat performance, only the most experienced pilots push an aircraft close to its limits at which point they might make a difference, but it will certainly kill a lot more inexperienced pilots by increasing the aircraft's accident rate. Poorer performance near the ground and higher landing speeds tend to do that.
They were an aerodynamic design feature of the aircraft, they were deleted from the Me 210 as a matter of expedience and this definitely contributed to the problems with that aircraft. Unsurprisingly, they were restored on the Me 410.
Cheers
Steve

Unfortunately, I was having a great deal of trouble with the message area last night, so I seem to have lost a portion of my comments regarding the slats and their value for low-speed performance.

(After several tries and a great deal of expletives, I was able to even get that photo attached!)

 

[tomo pauk]

The 'to-do list' tries to achieve what was achieved historically with Bf 109F-4, but it does not cover the things 109 really lacked - rate of roll, long range (in Japanese or American terms), a seamless itroduction of heavier firepower, tricky undercarriage geometry.
Trashing the 109E as an non-aerodynamic aircraft neglest the fact that was a simple solution to installation of much bigger, heavier and more powerful engine on an existing small and light fighter - ie. it was not ideal, but it worked. 109F was a general clean up.

I'd be also intererested in Leonard "Kit" Carson's view on how the US fighter aircraft could've been improved within 30 days, with name calling when that was not achieved.

 

[drgondog]

QUOTE="bobbysocks, post: 1269171, member: 33899"

(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.

Provide a much finer grain paint finish - eliminating camo not an option for LW

(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.

First, investigate the slope of the windscreen in a wind tunnel to see if a stagnation point at the base exists - if so, try greater angle similar to P-51D/FW 190 - and replace with blown canopy similar to FW 190D.

(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.

No. The wing slats a.) provided tip/roll authority by energizing the low speed airflow with the 'flow through' effect, b.) increased the CLmax at low speed for both turn and landing, c.) by thesis (according to Willi) decreased the wing form drag in comparison to wing twist.

(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."

No. The introduction of wing twist automatically introduces a complex design and test process to evaluate a.) The Twist, the design origin and extension of the Twist location, c.) evaluating alternative aileron designs for authority and effectiveness sans slats - particularly at extremes of low speed and high speed, d.) if aileron design changes, then what other effects are introduced - such as flutter, torsion, control reversal, stick forces, etc.

(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.

Maybe - but need metrics regarding 'unnecessary amount' of existing design compared to the alternative. The Germans were damned good engineers. Carson thinking about the P-51A to P-51B changes for lower cowl to reduce drag and maybe thinking 'one size fits all'. Lowering the inlet by definition increases the 'normal surface' of the entire inlet which could increase the flat plate drag of the component if bypass for the boundary layer is not provided.

(6) Install complete wheel well fairings that cover the openings after the gear is retracted.

Yes - but at what cost to complexity of the wheel well and wing attach design? Weight is a consideration, mfg cost is a consideration.

(7) Retract tail wheel. (Tom's Note: This was actually done on some models of the 109.)

Sure - but add system complexity and weight. Remember P-51H tail wheels were fixed in many cases without appreciable performance hit while increasing maintainability.

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..

A wind tunnel mock up yes - for comparison purposes, but 'adding wing twist', the right wing twist, the testing of the different twists, the increase in landing speed due to reduction of low speed CLmax as well as testing in air to air maneuvering. Then based on final decision create the necessary wing jigs for multiple plants, introduce the fabrication and assembly processes and slip the new model into production.. did I mention 'and do not disrupt existing production'??

IMO, the 109 design team took the most practical approach, namely increase HP. It worked for P-51B over P-51A as well.

 

[stona]

The retractable/semi retractable tail wheels fitted to various Bf 109s all proved tricky and unreliable. You will see more of the type, from F to K, where applicable, with the wheel fixed down. I've even seen pictures of some Ks with plating riveted around the deployed wheel to blank off (at least partially) the tail wheel recess. The minimal speed penalty was obviously deemed more acceptable than the risk of a tail wheel failure and subsequent damage.

A more relevant comparison would be with the Bf 109s contemporaries, designed in the early to mid 1930s. Very little was done substantially to improve the overall aerodynamics of the Spitfire either. At least the Bf 109 had puttied joins in the fuselage (the lines so beloved of modellers who like to segment their Bf 109s like a wasp, where the intermediate plates link those with the preformed 'frames' in their edges) and was flush riveted throughout, something that can't be said about any war time mark of Spitfire. The Spitfire featured some of which skins were still overlapped! The double row of rivets along the join at the leading edge of the Spitfire wing didn't get filled and sanded, along with the rest of the wing as far back as 20% of the chord, until 1942!

Cheers

Steve

 

[GrauGeist]

...tricky undercarriage geometry...

The main gear's design was also one that simplified production, offered ease of transport and provided a large advantage to maintenance. Not much could be done to change that without extensive frame redesign.

Also, by virtue of it's design (extending outward from the aiframe's centerline), wheel coverlets for the main gear when retracted would require an extensive mechanism that would not only add additional weight, but compete for space in the Bf109's small wing.

In regards to testing, Willy certainly made extensive use of his wind tunnel...

 

[pbehn]

What a team of experts can do in a specialist shop bears no relation to what can be done in mass production with newly trained workers. An F1 team has about 200 people about 50 of whom constantly build and modify 2 cars whose performance increases throughout the year. Just dont ask them to do it with 2,000 or 200 or even 20. Similarly a hand built Messerschmidt special would be flown by top pilot who wouldnt be fazed by landing without slats, the production Me109 had to be a plane that could be flown and landed by a novice on his first flight

A plane may go faster with a polished metal finish, it may be safer on the ground and low level with camo paint but the LW chose to paint the 109 with bright yellow noses because telling friend from foe trumps other considerations.

 

[stona]

That's the Luftfahrtforschungsanstalt Hermann Goering near Braunschweig. That is obviously a Bf 109, but Messerschmitt more commonly used the facilities of the Deutsche Versuchsanstalt für Luftfahrt (DVL) for obtaining test data
Cheers
Steve

 

[GrauGeist]

That's the Luftfahrtforschungsanstalt Hermann Goering near Braunschweig. That is obviously a Bf 109, but Messerschmitt more commonly used the facilities of the Deutsche Versuchsanstalt für Luftfahrt (DVL) for obtaining test data
Cheers
Steve

Yes indeed, but it's the only image I had on hand for the moment!

 

[stona]

A plane may go faster with a polished metal finish, it may be safer on the ground and low level with camo paint but the LW chose to paint the 109 with bright yellow noses because telling friend from foe trumps other considerations.

Yellow noses were applied at a time when the Luftwaffe was fairly safe on its Continental bases, later it was only the lower surface of the nose that received such a distinctive and camouflage compromising marking.
Later, as the allies became more dominant over Europe even the white of the national markings was reduced, deleted or sometimes greyed out. I've seen early/mid war pictures of aircraft at dispersal with the national markings covered with covers or foliage. There are late war images showing aircraft literally 'hiding in the woods'.

The Luftwaffe's theatre markings became more subtle when air superiority was contested and later IFF markings, like spinner spirals or 'Reich Defence Bands' are more comparable with the RAF's Sky fuselage bands or yellow leading edges.

Luftwaffe fighter camouflage went from an early green/olive brown combination, designed for camouflage on the ground, to various greys designed for camouflage at altitude, and finally back to green/olive/brown as the allies gained air superiority and hiding on the ground was once more the priority.

It was that Allies, notably the Americans, who felt that they could dispense with camouflage altogether late in the war, but by then they enjoyed total air superiority over their UK bases. They were unlikely to be attacked, on their bases, in daylight.

Cheers

Steve

 

[stona]

It's a great image of a 109 in a wind tunnel! From memory the DVL tunnels and the other ones whose name slips my mind at the moment couldn't test a full size aircraft.
Cheers
Steve

 

[Shortround6]

I would note that getting a smooth finish on a bare metal airplane may not be anywhere as easy as it seems, due to seams
Paint/putty helping to fill gaps and mismatches in panels which can be a large source of drag.

AS far as the slats vs washout thing goes, Drgondog or some of our other engineers may correct me but my understanding is that the slats are activated (by airflow over the area) just before stall, or in other words at an angle of attack just below that at which the airfoil stalls. The slats keep the airflow going over the wing and the higher angle of attack generates more lift in the area of the wing affected and the airflow is effective over the ailerons helping keep control of the aircraft, a double benefit.
Washout means the outer wing is operating at a lower angle of attack than the inner wing, the inner wing stalls before the outer wing and so the airflow over the ailerons is still effective (unless the stall gets really bad) however at any point in time the outer wing area/s will be generating less left due to the shallower angle of attack compared to the inner wing area/s or a similar wing with no washout.
Total lift from a wing is a complex issue with things like aspect ratio coming into play. It is not quite so simple as picking airfoil XXXX and using YYY sq ft and any wing using both those numbers will generate the same lift at the same speed regardless of shape/planform or washout.
During the design process the designers can "tweak" the wing (change shape and size) to get the desired lift at the drag that is acceptable to them and taking into account other considerations, like landing and taking off. Trying to "re-tweak" an existing wing is a lot harder. Do you make the wing larger (extend the wing tips) as you introduce the washout to maintain the same amount of lift at the same speed for landing? What does the larger wing do to drag at high speed?

Tail wheels are another example of one size does NOT fit all. Some planes show a significant improvement with a retracting tail wheel and some do not. I suspect (but could be wrong) that it has to do with how smooth the airflow is when it reaches the tail wheel. A flat bottomed airplane with a tail wheel sticking down may show a significant improvement. Some planes with a large curve in the bottom of the fuselage or with other bits and pieces hanging down (belly turrets, H2S radar domes or even P-51 radiator scoops) may have a much more disturbed/turbulent air flow in the tail-wheel area to begin with sticking a tail wheel into it doesn't change things much.

Something of the sort may affect using small doors to cover the parts of the Wheel wells the main doors do not. Not all planes used the same shape bottom to the wing (although differences were slight) and not all planes had the wheel wells a the same point in the cord not to mention that not all planes used the same size wheels (even fighters) so saying that fighter A picked up 6mph using the small wheel well doors doesn't mean that that fighter B will pick up the same 6mph increase at the the same speed/altitude.

 

[davebender]

Erich Hartmann scored 352 kills between 5 November 1942 and 8 May 1945.

Hartmann wasn't the only Me-109 pilot to rack up dozens (indeed hundreds) of kills right up to end of the war.

Seems to me Me-109G needed no improvement over what it got historically.

 

[pbehn]

Yellow noses were applied at a time when the Luftwaffe was fairly safe on its Continental bases, later it was only the lower surface of the nose that received such a distinctive and camouflage compromising marking.
Later, as the allies became more dominant over Europe even the white of the national markings was reduced, deleted or sometimes greyed out. I've seen early/mid war pictures of aircraft at dispersal with the national markings covered with covers or foliage. There are late war images showing aircraft literally 'hiding in the woods'.

Steve, I agree,
I was just pointing out that there was more to the surface finish than top speed. In the limit both the LW with yellow noses and Allies with black white stripes first on the Typhoon and then with D Day stripes threw out top speed and even ground camoflage in favour of recognition.

 

[gumbyk]

(6) Install complete wheel well fairings that cover the openings after the gear is retracted.

Considering that the wheel well fairings were commonly removed in service on FW-190's due to mud getting trapped in them - why put them on in the first place?