Aerodynamic modifications

[John]

Re: Aerodynamic modifications

Don't have time to do a lot of digging, but here are a couple that are handy...

Thanks!

[L.E.D.]

Re: Aerodynamic modifications

Found a little history on the P-51 cooling set up by someone who was there: Lee Atwood.

http://www.506thfightergroup.org/p51.asp

(Try not to get too distracted by the nice cockpit photos. )

[Curt_B]

Re: Aerodynamic modifications

Found a little history on the P-51 cooling set up by someone who was there: Lee Atwood.

http://www.506thfightergroup.org/p51.asp

(Try not to get too distracted by the nice cockpit photos. )

Nice. This thread is turning into a depository, as opposed to a suppository, lol, thanks to Y'all, even though some cockpit stuff creeps in every now and then.

Restricting the flow through the radiator, for different flight conditions, with the door creates spillage drag around the lip entrance. The roundy scoop lip mitigates that somewhat for off design conditions. The Dago Red splitterless scoop looks good. Was that the scoop for the fast runs, and record?

[Mluvara]

Re: Aerodynamic modifications

Not sure how many noticed this after the Gold race, but here's some unintentional flow visualization on Voodoo from the scoop area.

Michael

[wyhdah]

Re: Aerodynamic modifications

What?! Mustangs leak oil?! Watch out or the peanut gallery will say you guys were unprepared for that win.....

[ChrisMX105]

Re: Aerodynamic modifications

I wonder if the linear footage of potential oil leak (Gasket/Hose Connection) areas could be calculated on both a Merlin and a 3350/2800. I bet it would be crazy long. At least several hundred feet.................

[Curt_B]

Re: Aerodynamic modifications

Not sure how many noticed this after the Gold race, but here's some unintentional flow visualization on Voodoo from the scoop area.

Michael

[ATTACH=CONFIG]20317[/ATTACH]

Hi Mike, Thanks for the nice, clear photo. That angle off the longitudinal axis can be used for aerodynamic goodness.

[Curt_B]

Re: Aerodynamic modifications

I wonder if the linear footage of potential oil leak (Gasket/Hose Connection) areas could be calculated on both a Merlin and a 3350/2800. I bet it would be crazy long. At least several hundred feet.................

Several hundred feet of potential flow viz.

Dirt mixed with rain is good too. The vg's under the horizontal are to make up for coinciding the fat parts of the vertical and horizontal.



Curse of the aero guys attending events, they take pictures of details.

Here's a CFD depiction of a splitterless scoop in transonic flow with vg's modeled in the duct to control flow downstream;



Real life is better because model, and CFD, uncertainties are eliminated.

[Wild Bill Kelso]

Re: Aerodynamic modifications

I want to tuft test our doghouse to see what is going on inside.

[Curt_B]

Re: Aerodynamic modifications

I want to tuft test our doghouse to see what is going on inside.

Oil flow would reveal more. The trick is getting a reading on-condition. Grind up some colored chalk, mix it with a light oil, and introduce it into the duct at the flight condition of interest. Yellow against black gives the best visibility unless you want to play with fluorescent oil. Using a gopro camera mounted on the outside of the duct shooting through a hole in-flight would be ideal. It would be just as easy to illuminate for the picture with a black light. It'll take a few tries, but you can do it.

http://www.grc.nasa.gov/WWW/K-12/airplane/tunvoil.html

This would be a necessity for a splitterless scoop duct.

Example fidelity of the flow using fluorescent oil showing shock stall on the upper wing, and shockwaves being manipulated by anti-shock bodies to delay the stall;

[wyhdah]

Re: Aerodynamic modifications

Oil flow would reveal more. The trick is getting a reading on-condition. Grind up some colored chalk, mix it with a light oil, and introduce it into the duct at the flight condition of interest. Yellow against black gives the best visibility unless you want to play with fluorescent oil. Using a gopro camera mounted on the outside of the duct shooting through a hole in-flight would be ideal. It would be just as easy to illuminate for the picture with a black light. It'll take a few tries, but you can do it.

http://www.grc.nasa.gov/WWW/K-12/airplane/tunvoil.html

This would be a necessity for a splitterless scoop duct.

Example fidelity of the flow using fluorescent oil showing shock stall on the upper wing, and shockwaves being manipulated by anti-shock bodies to delay the stall;

[ATTACH=CONFIG]20326[/ATTACH]

Curt with this GoPro setup how would you keep the camera from influencing the air flow?

[Curt_B]

Re: Aerodynamic modifications

Curt with this GoPro setup how would you keep the camera from influencing the air flow?

If you can find a cavity on the outside of the duct, mount it there, and cut a hole in the duct to shoot through. If you're looking at the inside top of the duct, place the camera on the bottom. You can use mirrors if needed. If the hole gets big because of that, use some Lexan. There might be some spy type cameras in the James Bond catalogs if the gopro is too cumbersome and won't fit. (On a search for little bitty cameras, these came up, so packaging is solvable.)

https://www.google.com/search?q=tiny+cameras&espv=210&es_sm=122&source=lnms&tbm=isch&sa=X&ei=okNpUrzMLZG2kAenqIHIAQ&ved=0CAkQ_AUoAQ&biw=1777&bih=887

There's probably a smart, compact way to get the surface lite by scattering a laser or something. You creative types can figure it out.

The F1 guys are doing it with success;

http://www.auto123.com/en/racing-news/f1-technique-what-is-flow-visualisation-paint?artid=150654

Diesel can be used in place of oil I'd imagine. The problem with letting it dry out to set the flow pattern, is you wouldn't know when when it set - run-up, taxi out, climb, cruise, on-speed, landing, taxi-in, run-up. There's also pressure and temperature sensitive paint, but I've had limited success with that. When the set occurred would be the same question.

[RAD2LTR]

Re: Aerodynamic modifications

Not to get too far off topic but, one of the things I really like about driving my car in the rain is seeing how the air flows around it from the muddy spray left on the car. What is really cool about the car is that it was designed as a homologation race car (BMW E30 M3) by the factory so all the aerodynamic aids on it are functional because they had to be if BMW wanted to use it on the race car. BMW spent a lot of time making the car as clean as possible. Its pretty cool looking to see where the air goes and where it doesn't. Water on the rear window will stay there until it evaporates. The droplets don't move even at 80 mph. Any water on the trunk lid is blown dry.

I find myself looking at airflow patterns on cars during the winter all the time. Its fascinating to really see where the air goes.

Will

[Curt_B]

Re: Aerodynamic modifications

Its pretty cool looking to see where the air goes and where it doesn't. Water on the rear window will stay there until it evaporates. The droplets don't move even at 80 mph.

The flow's separated on the rear window - high drag

I find myself looking at airflow patterns on cars during the winter all the time. Its fascinating to really see where the air goes.

Will

You'll like this then. About a minute in, a horseshoe vortex is demonstrated. Like what exists at the wing fuselage intersection. There's also some rudimentary flow viz on diffusors at really low speeds.

http://www.youtube.com/watch?v=DOUfyDHxkYQ

Speaking of OT: If you get through all parts, I suggest doing something different for a while to uncross your eyes, lol. I went and flew the Cub after I watched it, and managed to get my first brake bladder to leak. Pretty good since it lasted 70 years. Have a handful of spares and like keeping the airplane stock, sans clipped wings. If anybody has spare Cub brake parts laying around, I'm in the market - pm me.

[Curt_B]

Re: Aerodynamic modifications

The flow's separated on the rear window - high drag

Or, for those that are positive thinkers, 'hi drag".

Posting the other two videos to make it easier on everyone;

http://www.youtube.com/watch?v=rDhSdtMjSpA

http://www.youtube.com/watch?v=uewkm_pKXOc