Flight model stuff

[DeeZCamp]

im sure hes seen it

<S> hazed

[-tronski-]

I can't believe I read the whole thing...

 Tronsky

[funkedup]

Here's that article in case anybody is interested.  I wonder if X-plane models aeroelasticity.    
 http://www.raf303.org/funked/cfd/

[ 07-02-2001: Message edited by: funkedup ]

[wells]

The P-38 flap lift might be a little low.  I'm measuring about a 60% increase from flaps, where it should be closer to 75-80% (from pilot manual, with airspeed correction).  The other US planes that I tested (F4u-1D, F6f, P-47D, P-51D) checked out ok with about 35% increase in lift from flaps.

I'm using speed trim with engine off and finding the exact speed where the stall warning sound starts, with both flaps up and down.  The idea was not to find the exact stalling speed, but the difference in speeds so as to find the % increase in lift.  In the P-38, I measured 132 mph clean and 104 mph with full flaps.

[Mark Luper]

For Deez and others...
A couple of my squadmates and I from the 56th FG went and visited HTC this morning. On top of having the opportunity to meet EddieK and seeing Thunder again we had a good session with HT. One of the things that HT wowed us with was the method they use to test aircraft in AH. It is a visual model with little arrows all around it showing amounts of thrust, lift, and drag. It can be applied to each airplane and one runs it in a arena offline. Got a glimpse of the "tables" he uses, I said a glimpse, it is an awsome table and the number of variables are mind boggeling. He wasn't showing us the tables, just noticed them when he was setting up the test.

Guys, these people are professionals. They definately know what they are doing and the extent of what they model is amazing. Example: the amount of wing flex induced by the ailerons in a roll with the resultant effects on flight.

Do they make mistakes? Sure they do. They are human and sometimes a value is misstyped. That they are willing to listen if someone has data to back up their thoughts is a real treat for us flying this sim.

I have some limited experience setting up flight models when I have modeled some aircraft in MSFlightsim. It doesn't have near the number of variables and it is difficult at best to get a beleivable and accurate flight model.

Give these guys a break. They deserve it  .
Post reccomendations all you want but back it up with hard facts and good data. Not "feelings"  .

[Toad]

Thanks, Mark!

[Tac]

*send a couple of shaved sheep to visit wells on these warm summer nights*

the man deserves it! *S*!

[F4UDOA]

Wells,

You measured what at 132MPH on the P-38? A stall or just stall warning? 104MPH with full flap? Seems a little high ehh?

later

[Zigrat]

the he said the first onset of stall warning... not stalling, but just the buzz.


One interesting thing about the p38 should be that the inner sections should stall out before the outer ones do. Since the inner sections will have no spanwise flow duue to the nacelle actingas a boundry layer gate, the inner section of the airfoil should have a lift/curve slope near the ideal 2Pi/radians, but should have a low maximum angle of attack. The outer sections, on the other hand, shouldhave a shallower slope but most likely stall at a higher aoa.

whats this mean? it means that it should be nearly impossible for ap38 to enter a stall where it loses aileron control unless flight speed is so low that there isn't enough dynamic pressure for aileron effectiveness.

[Checksix]

Originally posted by Mark Luper:
Got a glimpse of the "tables" he uses, I said a glimpse, it is an awsome table and the number of variables are mind boggeling. He wasn't showing us the tables, just noticed them when he was setting up the test.
[/URL]

till all these flightsims print these numbers in public then its all feel.

the experts here would have somethin to compare to.

i doubt any of these games want that fm info available for their competition though.  

[Dwarf]

Originally posted by Zigrat:
whats this mean? it means that it should be nearly impossible for a p38 to enter a stall where it loses aileron control unless flight speed is so low that there isn't enough dynamic pressure for aileron effectiveness.

Yes and no.  One of the things about working at/near stalling speeds is that dropping an airleron to pick up your wing can add just enough drag that the outboard wing panel stalls too.

Normal procedure in that part of the flight envelope is to pick up the dropping wing with rudder.  IOW, leave the ailerons alone even though they "technically" will still work.

Dwarf

[sling322]

Originally posted by Mark Luper:
For Deez and others...
A couple of my squadmates and I from the 56th FG went and visited HTC this morning. On top of having the opportunity to meet EddieK and seeing Thunder again we had a good session with HT. One of the things that HT wowed us with was the method they use to test aircraft in AH.

Gee....I went to visit HTC last Thursday evening and all I got was a couple of beers at Kirby's.  

<edit>
On second thought...I think my visit was a lot more productive than yours MarkAT.    

[ 07-09-2001: Message edited by: sling322 ]

[Westy MOL]

Thank you for that brief glimpse into the HTC in workings Mark! More or less re-inforces my pretty already substantial trust in them.

  Westy

[ 07-10-2001: Message edited by: Westy MOL ]

[funkedup]

Yes and no. One of the things about working at/near stalling speeds is that dropping an airleron to pick up your wing can add just enough drag that the outboard wing panel stalls too.

Normal procedure in that part of the flight envelope is to pick up the dropping wing with rudder. IOW, leave the ailerons alone even though they "technically" will still work.

The cool thing is that all that stuff happens in AH.  

[Westy MOL]

Punt - for Badboy