Bf 109E-4/N top level speed and related altitude

[greybeard]

Hi all!

I was unable to find on the internet, as well as on any of my books, neither German official documents nor Allied test reports (at least one was captured and tested: see here) about performances of this variant. According to higher power output of its powerplant and its higher rated altitude, it should have been significantly faster (I get 490 km/h at SL vs. 460 of the DB 601A-1 powered E-4 by simple calculation - whilst a 585 km/h around 5000 m would be expected by PC simulation), but can't find any substantiated evidence.

Thank you,
GB

 

[eagledad]

GreyBeard,

I also have not been able to find data on the 109E4/N. However, in Warplanes of the Third Reich page 550, William Green wrote that the performance of the 109T-2 possessed a performance closely comparable to the 109E4/N.

Follows is Green's performance for the T-2:
(Weight 6173, and emergency power, speed in mph)
Sea Level 304, 3280 feet 317, 6560 feet 328, 9840 feet 339, 13120 feet 351, 16400 feet 354, 19685 feet 357.

Green did comment that the performance was similar even though the T-2 had a longer wing span and greater area.

On page 552 Green wrote that the E4/N had an initial rate of climb of 3420 feet per minute, and reached an altitude of 16400 feet in 6.1 minutes. The E4/N could gain 1970 feet in a combat turn at an altitude of 3280 feet. Turn time for the E4/N at 3280 was 25 seconds for a 360 degree turn. Unfortunately, the weight of the machine was not given.

This is the only data that I have found on the E4/N

Eagledad

 

[greybeard]

Eagledad,

thank you very much for fast and competent reply.

That's incredible how Green's 489 km/h at SL coincides with my calculation. This also means that wider wingspan does not affect top level speed, on the contrary maybe it could allow higher altitude performance thanks to reduced vortex drag, I guess; hence the 575 km/h at 6000 m. I think actual top level speed of E-4/N maybe was obtained at lower altitude, though, just cause the shorter wingspan. I recall as well German official records about Bf 109F-1, with same powerplant, reaching 615 km/h at 5200 m.

All in all, I tend to trust in Green's values also for speed at height, but would be really curious to know why Green, that to say "that the performance was similar" should have had E-4/N values, didn't give them too! Otherwise, what was the basis of his statement?

Sorry for my ramblings and thanks again for the very useful information.

Cheers,
GB

 

[eagledad]

Hello Greybeard!

Sorry for the tardy reply. I am glad you found the data useful. As for your question, I also wondered why Green didn't post E4N data. Perhaps his comment on the T-2 v the E4/N was based on a report of some kind (pure speculation on my account!)

I am glad the data provided was useful for you.

May God always fly your wing!

Eagledad

 

[greybeard]

Eagledad,

you're very kind. I hope you may also tolerate my speculative mind. I thought again to Green's data and I believe he mixed and matched different sets of values. Indeed, since 570 km/h at 5000 m are perfectly comparable with the 555 km/h at same altitude got by earlier versions (E-1, E-3, from German official documents), and these latter were powered by the DB 601A-1, developing 960 PS at that altitude, to reach 570 km/h would have have been required (570/555)^3*960=1040 PS, which are significantly far from the 1175 PS developed in emergency by DB 601N, but close enough to the 1050 PS got by same engine at its lower rated power.

I mean that Green's data about Me 109T-2 as "similar" to Bf 109E-4/N should be splitted as follows:

at emergency power 489 km/h at SL and (presumably) 585 km/h at 5200 m (for comparison with Bf 109F-1)
at climb and combat power 575 km/h at 6000 m.

Respectfully,
GB