British FM killing the fun of the game for allied pilots.

[Crumpp]

it took 3 years to address a stability problem with the production types is really stretching feasability don't you think?

Not when Operating Notes are full of symptoms of instability, the test pilots continue to report the symptoms of instability, the pilot anecdotes convey the symptoms of instability, and an independent aeronautical research organization confirms the issue.

Oh yeah, the engineering solution to the issue was also enacted AFTER the Battle of Britain:




No, I don't think it is stretching feasibility at all.

It is one of the facts that helped Gates to win the adoption of stability and control standards in the UK during the post war period.

[Crumpp]

In that based on my 20 some years of being an engineer

The same engineering experience that led to your discovery of the creation of energy in airplane performance a few years ago, Tagert?

[JtD]

It's interesting that all tested aircraft displayed longitudinal dynamic instability. Thought so based on the tests I've seen, but never before heard this summary. Good to know for certain.

OTOH I think it is a pity what has become of this topic in the last 48 hours.

[Crumpp]

It's interesting that all tested aircraft displayed longitudinal dynamic instability.

Where does this come from??



It is patently false as a generalization.

While many WWII fighters were unstable in very specific conditions such as in climb power with a specific speed range or landing configuration.... most were stable and met the requirements.

It is was very rare for a design to be unacceptable over the range of the envelope such as the Spitfire.

[bongodriver]

Originally Posted by Crumpp

Where does this come from??



It is patently false as a generalization.

While many WWII fighters were unstable in very specific conditions such as in climb power with a specific speed range or landing configuration.... most were stable and met the requirements.

It is was very rare for a design to be unacceptable over the range of the envelope such as the Spitfire.

Read page 18 of the NACA report and note the conclusion of satisfactory for short period oscilations (remember they were the ones that really counted)
and was noted as satisfactory for stick force gradient appart from 'flaps down power on', page 19 is good reading too.
Then try to show your smug face here again when you realise you have been completely discredited.

http://jsbsim.sourceforge.net/spit_flying.pdf a link to the report

[JtD]

....most were stable and met the requirements.

Which requirements were there for long period dynamic longitudinal stability?

[bongodriver]

Originally Posted by JtD

Which requirements were there for long period dynamic longitudinal stability?

And this is the million dollar question, even Crumpps NACA 'bible' states that long period stability was not looked in to much as it is of no particular consequence....so it seems the much maligned Spitfire failed 'slightly' in a characteristic of little to no significance, in summary it can be asumed they used a basic rule of stability is beter than instability in this regard so they gave the Spit an 'F' and Crumpp something to cling to.

[winny]

Originally Posted by JtD

Which requirements were there for long period dynamic longitudinal stability?

The requirements are set out in NACA Report No.755. By R. R. Gilruth

I posted a link to it a couple of pages back.

EDIT:http://aerade.cranfield.ac.uk/ara/19...report-755.pdf

[JtD]

Originally Posted by winny

The requirements are set out in NACA Report No.755. By R. R. Gilruth

There's nothing about long period dynamic longitudinal stability in there, hence my question.

[swift]

Would you mind to continue the stability discussion in this thread:

http://forum.1cpublishing.eu/showthr...=33245&page=94


so we could continue discussing the general performance of the spit in the recent patch that is speed, overheating and climb?

Some people are interested in these issues.