Turn Performance Figures

[Blue Mako]

Originally posted by CyranoAH:
BTW, punto also means "knitwear"  

el knitwear

Has a ring to it.  Think I'll use that from now on to punt threads.  Thanks Cyrano

[haa]

Originally posted by Badboy:


I don't think a complete exposition exists at the moment, but it is planned. I'm currently in the process of completing a writing project for a jet sim and as soon as that is done I'll start work on a set of diagrams like this one that contains all of the information you mentioned and much more:

I hope to do that for all of the aircraft in AH, They will be made available on the AH web site.

Badboy

Badboy, if it would help you I can send you the data I have collected so far. Basically like the La5 data above, although some planes with various flap settings and bomb loads as well. I have tested the following planes, all at 1k alt with 25% fuel:

British: Spit V, Spit IX, Seafire, Typhoon, Tempest, Lancaster(!)
Russian: La5, La7, Yak-9U, Yak-9T, Il2m3
Italian: C.202, C.205
Japanese: A6M5, Ki-61, N1K2-J
German: Bf109F-4
US: P-47D-11

Offer is open to anyone interested. Or someone could help me post the diagrams here. How do I put an image here anyway?

/haa

[haa]

Originally posted by HoHun:

>Before I do that I would appreciate some feedback on my method.

Looks good :-)

I think the following conclusion from Bernoulli's law might be useful:

n~v^2

(n = load factor/"Gs")

With the right constant, the curve should run nicely through your data points until maximum Gs are reached.

Regards,

Henning (HoHun)

Thanks Henning! It fits very well for most of the planes! There are a couple of planes showing different behaviour, but maybe I can write that off as due to inaccuracies in my testing.

As an added bonus I get a good estimate of the stall speed. Most useful, thanks again.

/haa

[batdog]

HAA, Hammer from the Nazgul might be interested in your data for his website.


xBAT

[HoHun]

Hi Haa,

>Or someone could help me post the diagrams here. How do I put an image here anyway?

I think the usual way to do it is to upload the diagram to some place on the web, for example the webspace typically reserved for you by your internet service provider (ISP).

Once you've uploaded your image, it'll have a URL like
 http://for.example.its/~haa/diagram.jpg

Just hit the image button in the reply window, then insert your image URL into the window that pops up, and the image should display just fine in your message :-)

I'm looking forward to it!


Regards,

Henning (HoHun)

[haa]

La5 EM diagram:

 

It worked!  
More diagrams are on the way...

[ 09-17-2001: Message edited by: haa ]

[haa]

Here they are. The data is in a zipped Excel file at:
EM.zip

Enjoy!

/haa


 

[haa]

 

 

 

 

 

 

 

[haa]

 

 

 

 

 

 

 

[haa]

 

[HoHun]

Hi Haa,

hey, that was pretty quick :-)

The diagram is looking very nice, I'm really impressed!

If you'd calculate an average maximum lift factor from the values that didn't hit the G limit, you'd arrive at a smooth graph instead of the scattered data points you have now. This smooth graph would probably hit the G limit line at about 36 degrees per second and 310 mph IAS.

If you'd continue the graph to the right, you'd hit the structurally allowable top speed, sloping down from some value at 9G to a higher value at 1 G. For example, at 350 mph IAS the La 5FN seems to withstand 9 G, at 400 mph IAS it might only withstand 6 G, and 500 mph IAS may be the absolute maximum at 1 G. (At higher altitudes, the limit may be determined by compressibility considerations rather than by structural ones.)

By the way, if (as Gripen already suggested)you'd plot the diagram in a more conventional fashion with the load factor on the vertical axis instead of the turn rate, you'd arrive at a less spectacular but easier to read diagram :-)

Regards,

Henning (HoHun)

[HoHun]

Hi Haa,

here's an example for the processing of the raw data I mentioned:

 

Note that I calculated the value of the corner speed, as clearly visible in the shape of the curve :-)

So far, the characteristic values for the P-47 to be learned from this diagram are

- corner speed
- maximum load factor

It does not yet make a statement on the energy combat capabilities of the P-47, however.

Regards,

Henning (HoHun)

[F4UDOA]

Heya,

I think the 3G portion of the graph is sustained turn rate. But I'm not sure any of these birds can maintain a 9g turn. What is the criteria for the graph?

Also could you throw in the F4U-1D, F6F and P-51  

[HoHun]

Hi F4UDOA,

>I think the 3G portion of the graph is sustained turn rate.

In Badboy's diagram, it is.

>But I'm not sure any of these birds can maintain a 9g turn.

Not without losing energy, so much is certain :-)

>What is the criteria for the graph?

It portrays the limits of the aircraft's envelope.

Since the P-47 reached but didn't exceed 9 G in Haa's test, it can be taken to be one of the limits of the P-47's envelope. The 6 G limit in Badboy's graph is misleading as you can fly beyond that limit.

Whether you should is another question :-)

Regards,

Henning (HoHun)

[haa]

I think the 3G portion of the graph is sustained turn rate. But I'm not sure any of these birds can maintain a 9g turn. What is the criteria for the graph?

See my first post in this thread.

 

Also could you throw in the F4U-1D, F6F and P-51  

This is where I am hoping someone will say: "Hey, this looks easy. I can test a couple of planes and save haa from doing it all by himself"...  

/haa