Hurricane engine torque

[Viper2000]

Originally Posted by Sternjaeger II

wow, I'm surprised the thing gets airborne in the first stance! Does X-Plane model propeller cavitation too?

You can't get cavitation in air; cavitation is a phase-change phenomenon.

You can certainly stall the propeller in X-Plane, and it will suffer shock losses. Actually the propeller model is one of its nicer features.

However, in general the underlying assumptions are undocumented and subject to change without notice. So you build a nice model, and then find that Austin has decided to tweak something in the next version and suddenly the predicted performance changes dramatically.

For this reason, it can't be used for serious work where fidelity is important.

Austin is a law unto himself and his system does not necessarily follow the conventions one would expect (eg although the underlying model seems to use SI, airframe dimensions are input in decimals of feet. Meanwhile, propeller root and tip chords are input in decimals of inches...). The engine model is a bit crazy, kinetic heating data is very questionable for M>>2, transonic behaviour is obviously lacking in fidelity, etc etc.

It's very good at replicating Austin's personal flying experience, but that's basically limited to GA piston singles. So although the simulator will allow you to build a rocketship and fly into LEO, the results have problems.

Of course, the average user doesn't understand the limitations of the code, not least because the underlying assumptions are undocumented, and therefore tends to believe that because the computer told them that their design would do this then it must be true.

So I fear that it's probably only a matter of time before some fool conducts virtual spin testing of their homebuilt masterpiece in X-Plane and then wins a Darwin award by assuming that X-Plane has validity in this regime simply because it produces output...

[Sternjaeger II]

Originally Posted by Viper2000

You can't get cavitation in air; cavitation is a phase-change phenomenon.

You can certainly stall the propeller in X-Plane, and it will suffer shock losses. Actually the propeller model is one of its nicer features.

However, in general the underlying assumptions are undocumented and subject to change without notice. So you build a nice model, and then find that Austin has decided to tweak something in the next version and suddenly the predicted performance changes dramatically.

For this reason, it can't be used for serious work where fidelity is important.

Austin is a law unto himself and his system does not necessarily follow the conventions one would expect (eg although the underlying model seems to use SI, airframe dimensions are input in decimals of feet. Meanwhile, propeller root and tip chords are input in decimals of inches...). The engine model is a bit crazy, kinetic heating data is very questionable for M>>2, transonic behaviour is obviously lacking in fidelity, etc etc.

It's very good at replicating Austin's personal flying experience, but that's basically limited to GA piston singles. So although the simulator will allow you to build a rocketship and fly into LEO, the results have problems.

Of course, the average user doesn't understand the limitations of the code, not least because the underlying assumptions are undocumented, and therefore tends to believe that because the computer told them that their design would do this then it must be true.

So I fear that it's probably only a matter of time before some fool conducts virtual spin testing of their homebuilt masterpiece in X-Plane and then wins a Darwin award by assuming that X-Plane has validity in this regime simply because it produces output...

yeah sorry, we erroneously refer to stalling as cavitation, but in fact it's propeller stall. Sounds interesting, does it also make the typical noise?

As for your last statement, there's nothing better than natural selection man

[Peril]

Thanks Viper, you are resistant to change, having just re tested the Rotol version I do detect a roll to the right at low power. So it seem I was mistaken in that some left fin offset has been implemented already, so happy with that as logical in implementation of some offset..

As to the accuracy of the result, well, if CoD get a MkII I'll have the data to confirm that plane, which in turn can be used to reverse engineer the MK1.

So what officially is the Rotol Hurricane mk in game? A Mk1A? Correct labels will help define data here.

As you can tell I'm not that familiar with the European aircraft, for info US and Japanese are my forte'. However; I do have many gigs on German and RAF stuff I have acquired in my travels as well, BTW I didn't work on X-plane.

[Sternjaeger II]

Originally Posted by Peril

Think out of the presumptions you make for no trim change and the obvious is the following, plane designers don't build planes with disregard to torque. The outcome being there will be 'always' some consideration of this factor in the designs.

ha, maybe today, but back in the days there was a lot of pioneering in design.. the early Macchi fighters and designs suffered from the torque snap rolls for design flaws, and it's not until the Macchi 202 that they introduced a wing longer than the other to compensate for it (and still wasn't enough..).

[TomcatViP]

So if it's for the sake of sciences

But btw and I'msry If I blow all this lovely wall of smokes but 1300+ Hp for early merlin is still awfully overestimated. Did all the historians hve lied to us for such years ?

Before reading your reply I am packing all my books in the backyard with my diploma on top ready to set a holly fire

By the way : tail offsetting/twisting was a really draggy choice but used widely. Oh and don't forget were the torque act on the airframe to see it's a 3D prob tht need to be discussed with such a geo in mind (tip : early PushPull or Cessna 337 - Me 109)

[Viper2000]

Originally Posted by Peril

So what officially is the Rotol Hurricane mk in game? A Mk1A? Correct labels will help define data here.

Interesting question. I think it's a Mark Ia or Mark I revised, depending upon what nomenclature you prefer.

http://en.wikipedia.org/wiki/Hawker_Hurricane

Note that the stuff about water cooled engines running 70ºC cooler is not correct. It's probably meant to be 70ºF, since this would be about 39ºC, rather closer to the 30ºC reduction in metal temperature quoted by the RRHT.

Originally Posted by Peril

As you can tell I'm not that familiar with the European aircraft, for info US and Japanese are my forte'. However; I do have many gigs on German and RAF stuff I have acquired in my travels as well, BTW I didn't work on X-plane.

As for X-Plane, I simply mentioned it because it is a sim I am extremely familiar with, as I have used it for over a decade, starting back in the V.5 days...

[Peril]

You can't get cavitation in air; cavitation is a phase-change phenomenon.[...]

Mm, that phenomenon would be better referred to as a stalled prop or portion of the prop blade.

If it helps.

OH and don't trust wiki data, to unreliable, I see enough typos in core data as is

I have cooling tests here if they help? AVIA_681_Report_689c_Part_01_Page_19. The full document is missing, a bugga as I can't confirm which Hurricane.

[Viper2000]

There's nothing wrong with Wikipedia; it's pretty much as (un)reliable as any other secondary/tertiary source.

The world would be a much better place if people treated all sources with the same level of scepticism that they treat Wikipedia.

[Peril]

Yep, which is why I use primary data mostly and why I started gathering primary data 10 years back, to help improve accuracy of sims and educate myself in the process

[Peril]

Try the new patched Hurricane for trim, I think they fiddled with the Hurricane FM?? Some others have noticed changes as well, perhaps a bug fix somewhere?

Can someone else verify this, perhaps I'm dreaming or it's the bottle of Red wine??