Bf 109 G-10 vs K-4

[silence]

Can someone explain why the K-4 is noticeably faster than the G-10?:

342mph vs. 378mpf at s/l
426mph (max) vs. 435mph at approx.24,500 feet
K-4: 452mph max at 19,685
plus what looks like a much higher climb rate for the K-4

Is it simply the drag from the lower now cowl blister fairings? I can't imagine the G-10 being heavier enough to account for the

 

[69TA]

Retractable tail wheel with cover doors. On the G-2s a semiretractable tail wheel was known to be good for 12km/h at s/l versus a fixed tail wheel. The difference in drag between the large fixed tail wheel of a G-10 and the fully retractable and completely covered tail wheel of a K-4 ought to be even bigger than the G-2s.
Covers over main wheel wells. Got to be good for something.

 

[Denniss]

K-4 max speed was 444 mph with production prop, the 452mph is with an experimental prop. also speed is achieved with 2000 PS vs 1800 (or 1850?) on the G-10.

 

[alejandro_]

Many pilots preferred the G-10 as a dogfighter because it was lighter and the armament was more suitable. K-4 was equipped with underwing tubs. This meant the aircraft had a tendency to "float" a +28.000 feet. You can find more information in JG 26 diary, entry for 20 November 1944.

 

[Gixxerman]

Not to go OT (well it kind of is a G v K thread) but can someone clear up a little point of interest for me?

The Me109 G 14......are they largely indistinguishable to a K?

 

[69TA]

Very simplified, a G-14 is a G-6 with a DB605AS or AM engine. The G-14 belongs to the G series (Gustav) design. The K is a design model of its own with many significant differences compared to any G model. The high mark of the G series was actually the G-10 not the G-14.

 

[Denniss]

G-14 has AM engine, with AS engine it would be a G-14/AS. G-14 is almost identical to the G-6 but the G-14/AS looks more like a G-10. It may be possible to mix-up G-14/AS and G-10 with K-4 but G-6/G-14 should always be identifyable if the MG 131 cowlings (AKA bumps) are visible.

 

[kettbo]

G-6 + MW50 as standard eqpt vs add-on, radio changes, gauge addition or new designed instrument panel= G-14
the larger supercharger and refined cowl and the AS engine gives you G-6/AS and near identical G-14/AS
many variables but some of the late G-14s greatly resemble early G-10s
Some early G-10s had the /AS engine vs the DB 605D (IIRC, away from books at the moment)

Refined cowl plus retractable tail wheel, main wheel covers for the tire ends, plus more power gives you the faster speed for the K-4
at 400 mph, drag reduction is important
Less weight with most of the power gives you a better-handling G-10

The G series has the radio antenna near the back of the canopy when fitted
The K series moved the antenna back a frame, when one was fitted
K series moved the radio/eqpt hatch location, easily spotted when you look at profiles/drawings

Beware, I have not covered EVERY version, with Bf109 you could have a G-10 with short tail and an earlier G-6 with tall tail. Then long or short tail wheel strut, normal or late/large wheel bulges top of wing.

Best way to ID is to verify work number

 

[alejandro_]

I have been trying to find more information about the G-10 performance. The only speed graph I have found is from a Soviet book, see chart below. The maximum velocity is not that close to the K-4. I was wondering if there are other data to compare. Any reason for the lower performance?

 

[tomo pauk]

Lower performance - as 'why all of them have lower perormance than expected', or 'why the G-10 has a lower performance than K-4'? At any rate - data sheet with K-4 and G-14ASM (link).
The G-14ASM differs from the G-10 in engine type, that was 70 PS difference at 7.5 km. Reasons why G-10 was slower than K-4 are listed in 1st posts here.

 

[pinehilljoe]

Weren't the mass balance horns finally deleted also? A general aerodynamic cleanup.

 

[alejandro_]

Reasons why G-10 was slower than K-4 are listed in 1st posts here.

Both versions had the same engine. K-4 had retractable tail wheel and refined aerodynamics, but IMO the difference in performance is too high. At 6000 meters is ~40km/h.

 

[tomo pauk]

The shape of speed curve is not right for the G-10, if the power setting used includes usage of MW-50. OTOH, the shape of the curve for the K-4 is with MW-50 used under 7.5 km.

 

[Denniss]

None of the G-series power curves are correct, these sem to originate from some DB or Mtt tests with hydraulic supercharger coupling modified or disabled.
With the coupling enable you won't see the 'klink' in the speed curve with the second speed/stage kicking-in but a smooth raise like shown for the K-4

 

[tomo pauk]

None of the G-series power curves are correct, these sem to originate from some DB or Mtt tests with hydraulic supercharger coupling modified or disabled.
With the coupling enable you won't see the 'klink' in the speed curve with the second speed/stage kicking-in but a smooth raise like shown for the K-4

You're right.
OTOH - there was no second stage on the DB-605 engines before the 605L, and both stages were active (= impellers are rotating) with engine operating. Same single-shaft system as with DB 603L, Jumo 213E/F, and the 2-stage supercharged RR Merlin and Griffon.

 

[Denniss]

The DB engines very likely had a two-speed supercharger although this speed change was hidden by the fluid coupling.
At least this would be an explanation for the G-6 speed curves shown in this graph

 

[alejandro_]

Any background information on these performance data?

 

[Jaivan]

Any background information on these performance data?

Both come from Mtt AG Projekbüro:
- the one for DB 605 DM was in one of GL/C-E2 performance summary sheets
- the other for DB 605 DC came from sheets A/IV/39/45 "Steiggeschwindigkeiten für 8-109 G10 mit DB 605 DCM" (20.1.45) and A/IV/40/45 "Höchstgeschwindigkeiten für 8-109 G10 mit DB 605 DCM" (19.1.45)

 

[alejandro_]

Hello Jaivan, many thanks for your help.

Both come from Mtt AG Projekbüro:

Is it safe to assume that they are estimations? I am trying to compare the data with that shown in a Soviet book about aircraft development in WW2. The speed chart in this Soviet book was the only one I had for the G10 version before I found these German ones. See attached file.

 

[Jaivan]

Hello Jaivan, many thanks for your help.

Is it safe to assume that they are estimations? I am trying to compare the data with that shown in a Soviet book about aircraft development in WW2. The speed chart in this Soviet book was the only one I had for the G10 version before I found these German ones. See attached file.

Yes, they are calculations, but without details on exact configuration. It's also unclear the source for the G-10 curve in Samoletostroenie v SSSR. 1917–1945 book.