Best Messerschmitt Bf109 subtype

[Glider]

Take care, they will also try to make you believe that there is a tooth fairy and the moon is made of cheese.

[Lucky13]

The 109 Lair- The Online Source for Messerschmitt 109 information

virtualpilots.fi: 109myths

[claidemore]

Originally Posted by Kurfürst

I think an educated guess can be made using assumed values of drag, Oswald effiency etc. Then these can be applied to different altitudes.

A guess based on assumed values? I'd rather see some numbers.

I don`t think so.

I think so. See bottom of this post.

I would like to see that Mk XIV climb chart. I doubt it even exists.

My mistake, I was looking at the climb chart for the converted MkVIII airframe with pre-production Griffon. It is silly to compare operational planes to calculated test plane performance anyways, though any 21lb boost MkXIV is going to match or exceed that 4800-4900 ft/min estimated climb rate for the K4.

The figures you are using are referring to climb test done with a Mk IX missing ca. 300 lbs takeoff weight. Of course it climbs faster.

The MkIX in question weighed 7234 lbs, 'A' wing Mk IXs weigh 7205, so that plane was acutally 29 lbs heavier, and only 211 lbs lighter than a Mk IX with a 'C' wing.

Remove 300 lbs from any plane, and it will climb faster, too.



I`d say the fastest climbing 109 was the G-10 at 1.98ata.
The fastest climbing Axis fighter would be the Me 163, though, I don`t think there`s much comparison with... what, 160 m/sec IIRC?



It is a pity that +25 lbs was never cleared or used by the Griffon engined XIV operationally. I think it was tested once, and the engine immidiately failed. I haven`t seen conclusive evidence to the use +21 lbs operationally either, apart from anti-diver missions, though it was proposed for the 2nd TAF in late 1944, obviously for anti fighter use.

There is more evidence to support use of 21 lbs boost in XIVs than there is for 1.98 in K4s. So lets remove both from the discusion and concentrate on 18lbs boost and 1.8 ata.

Of course in the real world these comparisons meant little, given how rare the XIVs were.

Two famous quotes by Galland, one about Mk XIV rarity, one about his desire for a squadron of Spitfires. Do we believe..... both, neither, or pick one?
Over 900 Mk XIVs produced, compared to 856 K4's in 1944 and how many in 1945? Don't forget, the XIV wasn't the only fighter opposing the K4's, there were Mustangs, P47s, Tempests, Mk IXs, Mk VIIIs, La5s, Yak 9s, Yak 3's, La7s, P38s, and Typhoons. Still, we are comparing performance, not production.

A comparison of climb rates for "operational" 1.8 ata K4 and 18lb boost XIV and Mk IX with Merlin 66 18lbs boost. (based on historical data from Mike Williams site and Kurfurst site)

Mk XIV, 4700ft/min @sea level, 3650 @20,000 ft, 2100 @ 32,800 ft.
Mk IX, 4640 @ 2000ft (best climb is 4700) 3560 @20,000 ft , 1830 @32,000
109 K4, 4429ft/min @ 500m, 3543 @ 20,000 ft, 1467 @ 32,800 ft.

1.8 ata was only approved in January 45, so during 1944, the K4 had much lower performance.

Even so, Mk IX and Mk XIV with normal 18lb boost engines are outclimbing the 1945 1.8 ata 109K4s. Do we need more proof than that?

[DerAdlerIstGelandet]

Do not let this thread turn into a flame fest. This is a good informative thread and it does not need to be ruined.

That goes to all parties in this thread.

[claidemore]

Rgr that Adler.

Gotta admit, I was feeling a mite testy when I made my last post, other things in my life affecting my mood.

Claidemore

[Hunter368]

It will be interesting to see what the response is from Kurfurst, he does seem to know the Bf-109 very well. Lets wait and see.

[Soren]

you didn't even understand the Lednicer report Soren but you are trying to BS your way into being 'acknowledged' as someone who understands Aero.

And that rude remark amongst many other automatically puts you on my ignore list.

[Soren]

Simple don't always mean wrong.

Very true, however Bill doesn't understand this as he now sees himself as an expert over everybody else because he feels he won the argument over Lednicer's article.

Wingloading of the MkXIV was 35.1 lbs/sq ft, 30.7 for the Mk IX and 43.4 lbs/sq ft for the 109K4. That's a 21% advantage for Mk XIV and 29% advantage for Mk IX.

Which simply means it takes a 21% advantage in Clmax to gain the lost ground. Bill wants to slither his way around this by emplying that all these WW2 fighters were so different from each other in terms of aerolasticity and load symmetry that this means nothing, it's ridiculous.

As Bill claims: Nobody predicted viloent snap roll stall conditions in low speed high G turn for an Fw 190 because aerolasticity was not a well understood science.

Where are the facts and sources to back this up ??? Fact is that even TsAGl were very well into this area in the early 30's!!!

Fact is the FW-190 didn't have a violent stall purely because of aerolasticity, and it was infact predicted by Focke Wulf. The airfoil choice, the NACA 23000 series is in great part responsible for the violent stall. And the fact that wash out was applied to such a degree that much of the wing stalled at the same time was no disadvantage as Bill wants to make it sound like, it was purposely designed like that and Focke Wulf ofcourse performed tests to perfect the washout to permit maximum efficiency in maneuvers.

As I mentioned, the 109 wing is often quoted as having a clmax of 1.7 with slats deployed and possibly with combat flaps deployed.

Often qouted ? Claidemore it was established in multiple windtunnel tests conducted by Messerschmitt and is listed on every MTT aerodynamics chart on the 109. And it's NOT with flaps deployed, that would've raised the Clmax to well above 2.00. The Clmax of the Bf-109 F series and onwards is 1.7 with slats deployed clean, flaps and gear up.

(The RAE tests seem to indicate that their clmax calculations were with both slats and combat flaps.) Without slats, it is assumed to be 1.4. The slats therefore only give an 18% increase in cl.

Claidemore the slats give atleast a 25% increase Clmax and critical AoA in the covered areas, but only 48% of the 109's wing is covered by the slats, so the increase in Clmax by virture of the slats was somewhere in the area of 12.5 - 13%. The Clmax of the wing without the slats was already high, around 1.50 - 1.55, by virtue of the high thickness ratio.

The Spitfire MK IX is generally given a clmax of 1.6,

It is never given such a high Clmax figure Claidemore, that would be above the FW-190's Clmax of 1.58 which was above all others without high lift devices and much higher than the Spitfire's.

The Spitfire's wing's Clmax is 1.36 as established in windtunnel tests, which is only logical considering the very thin wing with a thickness ratio of 12% at the root to 9% at the tip. The 190's was 15% at root and 9% at tip and ion top of this with a higher lift airfoil. The 109's wing TR was 14.2% at root and 11.35% at tip, and again with a higher lift airfoil to start with.

a figure which my calculations support.

??? Could you show us these calculations ?

In my calculations for the Mk XIV with stall speed of 85 mph (as indicated in the pilots notes) and weight of 8500 lbs I get a clmax of 1.9.

A Clmax of 1.9 ?? Do realize how ridiculously high that is ? Btw, thrust increases Clmax (Or it really doesn't but it has the same effect as it accelerates air over the wings, creating more lift)

Btw, be careful about relying on IAS figures at landing, the high AoA of the wing will affect the pressure in the pitot tube.

[kool kitty89]

Careful guys, don't get this thread closed...

[Marcel]

Originally Posted by DerAdlerIstGelandet

Do not let this thread turn into a flame fest. This is a good informative thread and it does not need to be ruined.

That goes to all parties in this thread.

Ah... what a job you have here, Chris. Being the referee, keeping the fighters in their corners

[Soren]

Oh and about elliptical planform wings:

If truly elliptical they offer a high Oswald Efficiency factor, that's it.

However, the Spitfire's wing doesn't offer elliptical lift distribution because of washout, and neither does the P-47's. The Fw-190's DOES however, and this is because of washout, AGAIN done totally on purpose by Focke Wulf.

[kool kitty89]

But the full elliptical lift distribution of the Fw 190 will only take place when encountering the aeroelastic changes in high G maneuvers, correct? (hence why low speed/ low G stalls were not violent)

[Soren]

Yup, very correct KK.

And that the FW190 on top of this used the NACA 23000 airfoil only made the stalls even more violent, luckily control was quickly regained emmidiately after the stall as G dropped.

Fully ellipitical wings with elliptical lift distribution all suffer violents stalling characteristics, it's an inherent characteristic of this type wing.

[claidemore]

Originally Posted by Soren

Very true, however Bill doesn't understand this as he now sees himself as an expert over everybody else because he feels he won the argument over Lednicer's article.



Which simply means it takes a 21% advantage in Clmax to gain the lost ground. Bill wants to slither his way around this by emplying that all these WW2 fighters were so different from each other in terms of aerolasticity and .

As Bill claims: Nobody predicted viloent snap roll stall conditions in low speed high G turn for an Fw 190 because aerolasticity was not a well understood science.

Where are the facts and sources to back this up ??? Fact is that even TsAGl were very well into this area in the early 30's!!!

If you are going to use my posts to attack Bill, maybe you should take him off your ignore list and respond directly to him? Just a suggestion.


Often qouted ? Claidemore it was established in multiple windtunnel tests conducted by Messerschmitt and is listed on every MTT aerodynamics chart on the 109. And it's NOT with flaps deployed, that would've raised the Clmax to well above 2.00. The Clmax of the Bf-109 F series and onwards is 1.7 with slats deployed clean, flaps and gear up.

Yes, often quoted, and quoted again! lol


The Spitfire's wing's Clmax is 1.36 as established in windtunnel tests, which is only logical considering the very thin wing with a thickness ratio of 12% at the root to 9% at the tip. The 190's was 15% at root and 9% at tip and ion top of this with a higher lift airfoil. The 109's wing TR was 14.2% at root and 11.35% at tip, and again with a higher lift airfoil to start with.

Thickness ratio is very misleading here. 12% of the very broad Spitfire wing is still more than 14% of the skinny 109 wing.

??? Could you show us these calculations ?

Hehe, I'll show you mine if you show me yous. lol

A Clmax of 1.9 ?? Do realize how ridiculously high that is ? Btw, thrust increases Clmax (Or it really doesn't but it has the same effect as it accelerates air over the wings, creating more lift)

Now you'er trying to confuse me, it won't work.... (the man in black in the movie Princess Bride)

Btw, be careful about relying on IAS figures at landing, the high AoA of the wing will affect the pressure in the pitot tube.

Soren, you know how to calculate clmax as well as I (probably better). If you would bother to plug in a weight of 8400 lbs, stall speed of 85mph IAS (figure out TAS if you wish), and wing area of 242 sq ft (or use the extended wing area) you will get clmax of 1.88. I used 8500 lbs and got 1.9, my bad.

[DerAdlerIstGelandet]

Originally Posted by Marcel

Ah... what a job you have here, Chris. Being the referee, keeping the fighters in their corners

Yeap but some of the people here do not realize (you know who you are) that my patience is running thin...

If they dont quit the BS they might find themselves on an extended vacation.