Messerschmitt 109 Design Problems

[Graham Boak]

Apart from the lack of relevance of the BoB, a better case can be made that the Hurricane won it. Hence the Hurricane was the best fighter of WW2?

But if we are being serious, the British defence system won it, rather than any single weapon. Can we now get back to the design features of the 109?

[Nick Beale]

Originally Posted by RT

In it's class the P51 or the corsair, in the upper class the 262.

I agree that the Me 262 represented the next stage in technology but its actual achievements in combat were not so spectacular and nor did its pilots have a markedly better chance of survival. (There is an analysis of this in Manfred Boehme's book "Jagdgeschwader 7").

[RT]

We return to the first point the qty, Me262 don't won the war because, there is no in strength in 1942/43 2000 of them, 1944 need 4000 of them

Hurricane ? nd because they would hv enought of them

remi

Maybe the war hs been won by the liberal economy, so strange idea they hv to back-up the most anti-liberal system

[Franek Grabowski]

The war was won by superior economies and superior weapon systems. Mustang was only a part of a system but it was a high quality part, outclassing respective German pieces. There is a general tendency trying to prove German superiority in several areas, but mostly it is not justified at all.
Returning back to Me 109, it generally lacked development potential and it was not possible to put as much war load as necessary into it. No room for more weapons, more fuel, teardrop canopy, etc.

[RT]

trying to prove German superiority in several areas, but mostly it is not justified at all.
?????

At least they are the first to put a radar on a horse...



http://cgi.ebay.de/WWII-Foto-Funker-...QQcmdZViewItem

[Dick Powers]

Ah yes... the famous "Nacht Cavalry" with the steed camouflaged in late-war overall hellblau.

[Kurfürst]

Originally Posted by Graham Boak

I understand the loss in speed due to the gondolas as more than that: I have 15 in my memory, but whether that was kph, mph or knots I can't say! kph probably. The loss in speed due to the drag of internally mounted guns would be significantly less than that of the gondolas. Weight has a negligible effect on maximum speed.

The 109 wing wasn't significantly weak, and there's no guarantee that fitting extra open spaces would have strengthened it at all. Carrying weight outboard on the wing does reduce the bending moment at the root, but the penalty on agility would over-ride that.

Here's a recent post of mine on the subject, copied over from LEMB, for what it's worth :

Contrary to popular belief, the gunpods were not so hurting to performance, Soviet trials showed the following results with a clean and gondie G-2 : top speed 666/650 km/h at 7000m, time for a 360 degree turn at 1000m 20 sec vs. 22.6 sec, time to 5000m 4.4 vs 5.1 min.

Messerschmitt's specs for gunpods with ammuntion added 215 kg (135kg w/o ammuniton) to the takeoff weight, and a decrease of speed by 8 km/h at SL.

The weight increase was comparable to normal (inside-) wing installations, taking into account the weight of ammunition boxes, mounting rails for guns which the cannon gondolas contain in one single unit. As noted the gondola guns complete with housing etc., but without ammunition weight 135 kg for a pair of MG 151/20. In comparison, Fritz Hahn gives the installation weight of a pair of MG 151/20 complete with all accessories, but without ammo into the FW 190A-4/U8 as 126.7 kg.

As far as the drag goes, it would be interesting see the drag penaly for a internally mounted MG 151/20 in FW 190, but I've no such data; I have it for Spitfires though, which is detailed for various installations, understood for the change of speed at 360 mph. It goes as, as far as cannon armament concerned compared to the 'ideal' Spit, for our purposes, a Mk I without the cannons in the wing :

Two cannons : - 6.25 mph (ie. B-Wing
Two cannons and two cannon stubs : -8 mph (ie. C-wing)
Small bulge over wing : - 0.5 mph (late C-wing)
Large bulge over wing : - 1.5 mph (early C-wing)

This being compared to about 15 kph (~9mph) measured by the Soviets as speed penalty for gondolas at rated altitude of 7000m on G-2, and the 8kph@SL/~12 kph@VDH given by Messerschmitt in Leistungzusammenstellung Me 109G, here :
http://kurfurst.allaboutwarfare.com/...ragitems_table

The 109K-6's speed with the internal wing MK 108 cannons is given as apprx. 10 km/h slower than the K-4's at altitude.

Overall, it doesn't occur to me using gondolas were any heavier or draggier than using internal armament which would have resulted in some distruption of the aiflow near the surface, and some additional blisters on the wings. The gondolas may have been of greater surface area, but they pushed the gun well below of the boundary layer and probably made up for their greater size by causing less turbulance in the airflow. This was probably a very deliberate choice by Messerschmitt, who probably considered the need for such a heavy firepower involving three fast firing 20mm cannons only required in special cases, as so opted for removable gondolas which does not seem to hurt performance any more than internally placed cannons. When carrying gondolas, the early Me 109Gs could match the FW 190's firepower, as well as speed at altitude, rate of climb and turn.

PS : Spanish 109G 'Buchon' airframes had carried Hispano cannons inside the wings, so it was certainly technically possible..

Kurfürst! - The Messerschmitt Bf 109 Performance Resource Site
http://kurfurst.allaboutwarfare.com/

[Graham Boak]

Getting out of the boundary layer would have increased the drag, so that argument is self-defeating. In a boundary later the flow is slower, hence any protrusion creates less drag inside than outside. However, this near the leading edge the the boundary layer is insignificant. A gondola is just a large blister, of considerably greater cross-sectional area and poorer aerodynamic profile: the increased surface area is only one contribution to drag.

The prime contribution to drag (in either kind of installation) was likely to be the barrel, with cross-flow separating from the downstream side and creating base drag. Circular sections are poor. This may point at one possible benefit from the Messerschmitt installation. The airflow near the leading edge of the wing is flowing from the stagnation point, which is behind the leading edge, and so flow at the base of the barrel (Spitfire mounting) would have a considerable cross-flow element - around the barrel rather than along it. With the barrel mounted below the wing, it may have avoided this particular condition. I'm not completely convinced by this argument - we are looking for drag forces along the aircraft axis not an extra force upwards. However, the lowest drag for an engine installation, or store carriage, is found below and in front of the wing, and that is where the barrel is on Messerschmitt's installation.

This may have been an inadvertent result of the decision to use easily-removable gondolas, for Messerschmitt's twin and multi-engine types don't demonstrate knowledge of this effect. It was discovered at the RAE between the design of the Halifax and the Lancaster.

[Kutscha]

The 190 with the dual 20mm gunpods had a loss of speed of between 19 and 25mph, depending of the height.

One must really question the 109 speed loss with gondolas as the tiny bomb racks on a P-51 resulted in a greater speed loss.

[George Hopp]

T

he 190 with the dual 20mm gunpods had a loss of speed of between 19 and 25mph, depending of the height.

In spite of the increased firepower of those dual 20mm gunpods, it was not popular because it reduced maeuverability, speed, and ceiling.

This was the problem with the 109 gondolas. They may not have done much to reduce speed or ceiling, but they certainly reduced maneuverability. And, without the gondola-mounted guns, the firepower of the 109 was pretty pathetic.