Spit/109 sea level speed comparisons in 1.08 beta patch

[Kurfürst]

Originally Posted by Holtzauge

There are a number of issues with the outlyer 109E 500 km/h sea level top speed:

First of all the Baubeschribung 500/570 Km/h speed curve does not map any known engine power/alt curve: These either have the characteristic bulge associated with the hydralic clutch or the notch type with two speed superchargers where as the curve showing 500 Km/h at SL and 570 Km/h at altitude in the Baubeschribung has a straight line between these points.

The Baubeschribung curves are obviously simplified, drawing a straight line between low level and FTH performance. Again, nothing uncommon in that, Rechlin did the same thing for a tested G-1 chart:

So which DB601 in a series Me109E had this power/altitude characteristic? None that I have seen published.

All, in fact:

In addition, it looks like estimate for the "guaranteed" engine data coming close to 500 Km/h for the V15 prototype is for 1,35 not 1,3 ata.

Unsurprising, since both the V15a flight tests results and guaranteed specs in the Baubeschreibung are for 1.35ata.

The sillyness lies in that some people want to compare these 1.35 ata results to 1.3ata, uncorrected figures, and the fact that uncorrected results achieved with the less powerful DB 601A-1 at 1.3ata / 990 PS are irrelevant when modelling our 1.35 ata / 1045 PS Bf 109E equipped with the DB 601Aa.

The rest of your post is irrelevant.

BTW it's worth comparing the V15a (WNr. 1774) results with the speed results with a Swiss export Bf 109E-3a. The reports show remarkable similarity in the top speed achived at altitude with the original VDM propellor of J-347 (572 vs. 564 km/h at rated altitude), especially when taking into account that J-347 already saw considerably use. However the low level speeds diverge greatly (498 vs 464 km/h at 0m altitutude). Note that the low-level performance of V15a with the Höhenlader (high altitude supercharger speed, or 'F.S gear' in British terms) shows good agreement with J-347 at both high- and low altitudes.

This would suggest that J-347`s level speed results were achived with the Höhenlader in operation and agree well with the results of Bf 109E-1 / V15a WNr. 1774.

Also note that the Baubeschreibung agrees well with the V15a results, but the curves are bit more simplified (mean avarage results).