Ju87D Maximum G-load question.

[Evgeny Velichko]

Greetings gentlemen!

I have a question:

What was the maximum G-load of Ju87D, the limit when it could lost its wings during to fast recovering from dive?

Some sourses say maximum was +9G for it. Is it correct?

[edNorth]

Manual talks about 6 G´s on recovery of Ju 87 B-2 version, on radius of 450 meters... Page.29 ( I do not think Ju 87 Ds were different in structure, but engine etc.!)
https://ww2aircraft.net/forum/thread...-manuals.5504/

But it so happens this is target G. For enduring 6 G safely (I have done this often!) you need have 50% safety factor built-in and material safety factor (10% to 25% depending on material, so 11,25 Gs is very good, but not good enough for modern fighters!). But just slightly damaged structure reduces this. Saying 9 Gs is just a figure, one can also say wings could be long gone by then, if encountering strong gust, say -/+10 m/s gust as Modern Gliders must endure. Here fatigue cut in (and is the reason for 25% material over design, usually ...)

[stephen f. polyak]

Here,

https://books.google.com/books?id=M_...actors&f=false

USAAF standard load factor is given as 8.33 g, British as 5.33 g. Not stated if limit or ultimate values.

But here,

https://ww2aircraft.net/forum/thread...uations.23614/

it's given as 8 g limit and 12 g ultimate for US WWII fighters. Values less for a bunt (-g) or as aircraft weight increases (-/+ g). I doubt the Stuka was built to higher values; humans have limits, too.

Highest loads for Stuka would be when pulling and rolling to dive and when pulling out of a dive. Being slow lessens applied loads, which Stuka was.

[Evgeny Velichko]

Thank You very much.

So, was is +9 or +11,5 we cannot be sure?

I am just asking, because Il-2 '42 had max.G-limit as 10,5, Pe-2 dive bomber - 11,5 e.t.c.
Why Stuka (designed specially for diving) would not have lower level of G-limit?

[edNorth]

G-loads (Ultimate) for Ju 87 likely was around the 11,5 G mark, depending on safety factors. I say this because max operating Load is given 6 G. Variables are all there laid out, but say otherwise, one most enter calculations and have correct factors.

[Evgeny Velichko]

Agreed. But I need it written somewhere in documents to approve it.

[Kari Lumppio]

Privet Jevgeni!

I do not think the ciritical G-load is only one number. Factors for wing strucure failure also include:
- angle of attack (= amount of tangential load forward). Speed related.
- aileron deflection (= torsion load). Like in evasise manouvers.

High AoA (tangential load forward) can double the wing spar critical point stress in certain structure types. Torsion load is very difficult to analyze.

Good luck,
Kari