Biplane flight dynamics

[dgillmor]

Hi Flight Simmers,

I am relatively new to flight simming and have been downloading several aircraft for use in FS2002 and FS2004. I am very interested in WWII and Pre-WWII aircraft, especially biplanes! Based on limited experience with FSedit, Aircraft Container Manager and the flight dynamics files of the default sopwith cammel and many other biplanes I have downloaded, It doesn't look like FS/95/98/2002/FS2004 recognise the input of two main wings?

Is there a standard formula for combining the area, span, cord depth, sweep, dihedral, angle of incidence, wing twist and offset from CG of two wings? Many of these things should effect the various momments of inertia in the weights and balances section also. Does one just fudge the figures untill a stable flight model emerges from the muddled data? Or is there a notation format for entering [wing1] and [wing2] data in a .cfg or .air file?

I would be pleased to hear from anyone who can shed some light on this for me :)

Don

[Ian]

Hello Don,
yes there are standard formula featured in most of the early books. Off the top of my head I don't have them.

Have a look for references in:
http://perso.wanadoo.fr/hsors/FS_Soft/aerolinks.html

IF it is not somewhere in there I can always look it up, but confirm that it is not in there first :-).

I think Jerry's SS will design bi-planes. Do you know how to get to AvHistory?

Ian

[dgillmor]

Hi Ian,

Thanks for the website referral. The reading there will be very helpful. Obviously it will take time to peruse and understand it all. My college aerodynamics course is thirty some years in the past and mostly unused since. So far I have not found the answer to how one combines the design parameters of two wings to act on a single point relative to the CG but will keep looking.

What is AvHistory? Don

[Ian]

AvHistory is:
http://www.avhistory.org/scripts/MegaBBS/category-view.asp

Look at 1% for Jerry's SS

At least you did aerodynamics I only have read the books.

Get back to me if you can't find Munk's formula.

Ian

[Ian]

Hello Don,
The formulas are in Diehl (1927,193?) most completely and the only recent book is Stinton's Design (2001) p.164-178.

http://www3.addall.com/New/compare.cgi?dispCurr=USD&id=367469&isbn=1563475146&location=10000&thetime=20031031020340&author=&title=&state=AK


Ian

[dgillmor]

Hi Ian,

Thanks again for info. Will persue Diehl and Stinton as soon as time permits. Have been playing around with 1% spreadsheet since you clued me into AvHistory. It is intersting software and at least one version does accomodate some biplane set-up parameters, but not two separate sets of wing data (unless I've missed something, which is possible). I think one needs to have applied the above mentioned formula first. Have also been working on the visual model in FSDS v.2. I modeled a 9 cylinder radial engine in 3D(possible mistake) rather than paint a texture on a flat disk. I think the engine takes up more rendering time than the fuselage at its current state of completion. Haven't tried loading it in FS, yet. I hope to complete fuselage and wings this week end.

In the mean time I've started a private pilot ground school class to keep from getting bored. My instructor said that putting CG at CL creates longitudinal instability (which is a problem my flight models have displayed). So why does FS assume CG at 1/4 chord when moving it forward stabilizes the aircraft? This looks like it could become a running conversation. Please feel free to contact me at my email address of dgillmor@rt66.com if you'd like. Don

[Ian]

Ok, but better to continue at a more appropriate place.

Air File Board, post March 2003
http://www.avhistory.org/scripts/MegaBBS/logon.asp

but 1% stuff should be discussed on the other forums on that site.

Ian

[dgillmor]

Hi Ian,

I couldn't find either book you recommended in my local library system, so have ordered the 1943 ed. of 'Engineering Aerodynamics by Walter Deilh'. It had double the pages of the 1928 ed. with expanded tables and illustrations, plus an index. Guess I'll find out if it has the same info. May purchase Stinton in future, but have a lot of info to digest at present. In mean time I have posted my ?s regarding biplane entries in 1% SS on that forum. Thanks -Don-

PS the www3.addall.com is another great resource. In the past I had been searching several of the indiviual antique book sites seperately.

[Ian]

yes I bought a lot of books using that comparison and saved lots of money though try to avoid the express air mail charges.

The Diehl 1st edn. was in our Co library as the Co must have bought it then so I have not seen the 2nd edition.
It has the most biplane data I know. I presume it was 2nd hand.

I bought Stanton's Design which is very good for subsonic aircraft.
PS it comes in various editions at very different prices. Look for the AIAA pbk edition.

QSY: to AvHistory.

Ian