Perpeller beanie stuff ..aka Aerodynamics

Anything to do with Aircraft Design, FSDS, G Max, Aircraft Animator, SDL Edit, etc. Novice or skilled - stop here & learn!

Perpeller beanie stuff ..aka Aerodynamics

Postby Grayeagle » Sat Dec 17, 2005 12:51 pm

Hiya :)

Like you, I am an airplane nut.
Built tons of models as a kid, built and flew my own designs in U-control and later Radio Control .. then later became a student pilot and now I fly for the fun of it when I can.
Along the way I took Embry-Riddle's perpeller beanie course .. er .. aerodynamics .. and for a time I was paid to build 3d models of aircraft and other bits for video games.

A few things I have learned along the way I thought may be useful to those who like to model these aluminum-fabric-titanium works of art and have them 'fly' fairly well in MSFS.

I am goin to take it for granted that you know the basic terms I use.. if not, just ask :)

Most of this applies to the piston engine hot-rods of WW2 ..and most GA types.

CG ..1/4 to 1/3 of total distance from leading edge of the wing. If it's too far forward. . you need massive elevator input to effect a change in pitch.. if its too far back.. elevator is very sensitive and can stall *easy* and often.

Incidence .. planes were designed with 1 degree or more.. up to 5 degrees for the heavy lifters. This is a compensating mechanism ..as speed builds up, lift available increases.. adding to the lift generated by the wing. Planes require nose down trim as speed increases. The benefit is .. if you lose power ..she will trim nose up automatically ..reducing the pilot workload on approach and in some cases compensating a bit for the low-wing flaps trying to pitch the nose down.

Wing twist ..comparing root and tip incidence ..the tip is angled down compared to the root. Planes are designed with 1-3 degrees of it. The benefit is, the wing will stall at the fuselage first, allowing the ailerons to be effective even when most of the wing has stopped flying. Roll control on approach is a good thing.

Something the real spit pilots have to watch for very closely.. due to elliptical wing, the stall wave progresses parrallel to trailing edge ..first indication of a stall in a real spitfire is loss of aileron control.. very bad on approach if you have to add power :(

Engine thrust .. 1/2 - 1 degree nose down reduces pitch changes when power is applied or cut dramatically. 1/2 a degree to right or left will counter a lot of the P-effect generated by the prop on takeoff roll.

These are some of my favorite things :)

-evil grin- ..using these principles ..I modified the Rans RV-8 add-on to emulate a turbo IO-600 (fictional engine) that makes 850 hp ..its an evil little airplane that is a blast to fly, stable as a rock, can hang on the prop ..sort of a poor man's Extra 300 :)

-Grayeagle
User avatar
Grayeagle
Ground hog
Ground hog
 
Posts: 5
Joined: Sat Dec 17, 2005 12:36 pm
Location: Phoenix, AZ

Re: Perpeller beanie stuff ..aka Aerodynamics

Postby Felix/FFDS » Sat Dec 17, 2005 2:31 pm

Hiya :)

Like you, I am an airplane nut.
.....


and for a time I was paid to build 3d models of aircraft and other bits for video games.



There are times when one's two hobbies come together, and this is one of them.

One of the first, if not the first, massively multi-player online WW2 air combat simulations was
Felix/FFDS
User avatar
Felix/FFDS
Administrator
Administrator
 
Posts: 16776435
Joined: Wed Jan 31, 2001 9:42 am
Location: Orlando, FL

Re: Perpeller beanie stuff ..aka Aerodynamics

Postby Travis » Sat Dec 17, 2005 4:15 pm

Welcome to the forums, Grayeagle.  Sounds like you have some amazingly comprehensive knowledge to throw in.  Hope you stick around!  We could certainly use an aerodynamics guru around here . . . (no offense, Felix! ;))
Image
User avatar
Travis
Major
Major
 
Posts: 4381
Joined: Thu Feb 06, 2003 3:17 am
Location: KAUS - 30 MI NW

Re: Perpeller beanie stuff ..aka Aerodynamics

Postby napamule » Wed Dec 28, 2005 1:39 am

Right on! Grayeagle should hang around as there is a need for 'qualified' (as in real life) aerodynamic mechanics in FS. Ones willing to help, that is. I am sure they're out there, but not redily apparent or accessible sometimes, especially for 'advice'.

I am an aircraft nut (since FS98) too. I tweak cfg and air files since then. But technical specs (the 'why' it works/don't work in FS) is hard to come by. Then there's the 'real' versus the 'FS' version of model and then is when it all goes to pot! But, this is when it also gets interesting. So TWEAK I MUST. Cheers.
Chuck
Edit: So what I am trying to say, is FS need a place to take just released AC's where there is input, then concensus, about what needs changing (ie: tweaking). A place where one can 'take it apart, and put it back together' to where it 'flys' right. Several people (Chicilo, Jones come to mind) are trying to offer 'improvements', but it's their version of how it should fly, (as would be my tweaks too, of course) but not the definitive one. (See 'bouncy-bouncy' post to see just how complicated it all can be). If all of us could put our 'heads together' THEN it would be 'progress'. Otherwise it's just 'jerry rigging' it. Know what I mean?
Last edited by napamule on Wed Dec 28, 2005 1:55 am, edited 1 time in total.
i7 2600K @ 3.4 Ghz, Asus P8H67 Pro, Super Talent 8 Gb DDR3/1333 Dual Channel, Sapphire Ati Radeon HD-5770 1 Gb DDR5, Corsair 650 W PSU, Acer 23 in LCD, Windows XP SP2, MS Sidewinder Precision 2 Joy, Logitech K-360 wireless KB & Mouse, Targus PAUK10U USB Keypad (sits LEFT of Keyboard) for Throttle (F1 to F4)/Spoiler/Tailhook/Wing Fold/Pitch Trim/Parking Brake/Snap to 2D Panel/View Change. Installed: FS98, FS2k2, FS9 and FSX Acceleration (locked at 30 FPS).
User avatar
napamule
2nd Lieutenant
2nd Lieutenant
 
Posts: 270
Joined: Mon Jul 22, 2002 4:50 pm
Location: California


Return to Aircraft & 3D Design

Who is online

Users browsing this forum: No registered users and 374 guests