Flight stability issues of the Ta 152

[spicmart]

There are original documents about the surprisingly big difficulties of the Ta 152's flight stability and the proposals to improve it.
Anybody heard of it before?
The scanned documents can be found here:

Fragen zur Dora/152

Korrekt, Peter. Ich habe Fotos von den Beschussversuchen. Die wurden in Frankreich durchgeführt. Wenn gewünscht, fotografiere ich die mal flink ab. Ein (!) guter Treffer mit 30mm Mine reichte, um einen Bomber abzuschießen.

www.flugzeugforum.de

You have to sign up though to see them and it's worth it as a lot of original documents are posted. It's the premier German aviation site.

Here is a translation of said documents into English. It's chronological.

"Both the first production aircraft of version H and the model aircraft of version C have insufficient stability over the longitudinal and lateral axes.
As an immediate measure, the head of TLR therefore decided to reduce the fuel supply by 70-80 liters. and the entrainment of only 70 ltr. MW 50 instead of 100 liters suggested (this only with regard to the longitudinal axis?)
The head of TLR was subsequently informed that in order to achieve perfect stability around the transverse axis in the first series aircraft (H), it was necessary to attach approx. 58 kg of ballast to the engine and the fuel content of the rear tank of 360 ltr. to be restricted to 280 liters.
However, it is not possible to attach the ballast to the engine.
Chief TLR therefore proposes not to install the GM-1 installation, especially since the proper functioning of the pressurized cabin is still in question. The ballast on the engine and the fuel restriction could then also be omitted (in this case).
A meeting with the E-Stelle (Test Center) Rechlin showed that this proposal by the head of TLR would, in the opinion of the E'Stelle Rechlin, not be a remedy .

The E-Stelle also stated: The vertical axis stability of the 8-152 H is just sufficient. However, according to the shooting school, shooting approaches are not possible. A slight improvement occurs with the help of the course (direction) control K-23.
Rechlin suggested a different stretch (aspect-ratio?) of the fin to Focke Wulf as a remedy and sketches for it were handed over to Focke Wulf.

Transverse axis stability is poor for both C and H.
In principle, these instabilities around the transverse axis can be eliminated by:

Abandonment of course control K-23
Abandonment of GM-1 installation
Abandonment of 115 liters tank
Abandonment of FuG 185
Reduction of the fuel supply by 135 ltr.

Such a waiver, not even the smallest reduction in the fuel supply, can under no circumstances be approved!
In addition, when carrying out these measures, a top-heaviness near the ground would have to be accepted.

Fundamental measures were discussed:
a) Enlarging the horizontal stabilizer by adding edge caps
b) Modification of the wing transition to the fuselage to achieve better flow conditions
c) Engine pitch forward 0.5° further
d) Try to move all the weights further forward if possible
e) to compensate for the ballast of 13.5 kg previously required in the rear with a wooden tail

An aircraft with the above difficulties is unusable for troop deployment.
A complete remedy seems possible only with fundamental means."

 

[spicmart]

This is some serious flaw which amasses. I wonder how, in the end, the engineers and pilots solved this stability issue. I guess with the Ta 152H-1 being a production model one would assume that the problemhad been overcome. If so, to what degree?

I will summon some knowledgeable folks here.
tomo pauk
C CORSNING
S Shortround6

 

[thunderbird]

obviously the center of gravity is too far aft, which would mostly affect longitudinal stabilty. I think all the components and tanks listed are behind the pilot seat. Airplanes can be flown with negative stabilty, (As the Wright flyer was designed to be), but it gets more difficult the faster one goes. The management comments seem to indicate that the decision makers were ok that they'd lose a few airplanes to accidents. Or lots of airplanes more likely, but they weren't the ones flying.

One could fix this by moving the engine forward a few inches, with all the redesign work that entails. But then other problems might creep up and you'd have kludge after kludge.

Interesting enough, the B-52's best range occurs when the airplane is flown at a negative five percent longitudinal stability, as I recall, and even though the airplane was manageable, the Air Force did not implement that idea.