Speed Demon Wind Tunnel Test

[2club]

No one knows what 2016 will bring in terms of salt conditions, but the Speed Demon team is wasting no time in preparing to run the new car. Here's a link to a short story about this week's wind tunnel test and what they have planned for the future. Cool video included.
http://hotrodenginetech.com/smokin-the-speed-demon/

[Peter Jack]

Thank-you for the video and pictures. And thanks to George Poteet for allowing the world in to view the build. It gives people a great insight into what it takes to build a safe and fast record breaker.

Congratulations to George and the entire crew for a job well done. I look forward to many more positive results. 

Pete

[sofadriver]

Sure beats the 3 leafblowers I aimed into a plywood tunnel for my testing!  Shouldn't that cameraman have been downwind?

I sure hope they find a place to run.

[Blue]

Wow, I never expected the airflow behind the cockpit to be that unstable.  0:26 to 0:35 the flow from the mid cockpit to the rear wheel well bulge is completely detached from the bodywork.  I would not have expected this, the evidence is obvious.  Smoke does not go randomly sideways in attached flow.

Tuft it, the degree of recirculation in the apparently "clean" areas is extreme.  Some video of the rear and underside of the car with tufts would also be much more informative than blowing smoke over the front.

[distributorguy]

I didn't think there was a way to make a concave surface "clean" when its both preceded and followed by a larger convex surface.  The body shape is pretty, but it would make an unstable bullet.  Wouldn't a straight profile have less overall drag? Tried and true. 

[Eddieschopshop]

I think they are probably holding their cards close for obvious reasons on the rest of the video.  Whats everyones thoughts on the "hips" of the car and the angle the body comes in afterwards?  I have always wondered how the air would stay attached after the tire bulges,  if it could make that corner and not seperate.  I assume people smarter than me don't think it a problem or else it wouldn't be that way.

[Rex Schimmer]

I to would like to hear the "reasoning" for the shape of the car. As Eric (Blue) identified the air flow between the cockpit and the rear wheel covers certainly appears to be unattached. Maybe something that we are not privy to happens to the flow at the projected higher speeds that this car is targeted to run and is not observable at the lower wind tunnel speeds. I do think that they do have some level of aerodynamic expertise on staff but have never heard who it might be. More data, as Eric outlined, would be interesting but probably not going to be provided to us. It will be fun to see if the new car will be equal to the older car.

Rex

[distributorguy]

I bet George Poteet would share the info, if he knew this thread existed, and if he was privy to the info.  I'm no aerodynamic expert, but what happens inside a cylinder head should also exist outside the car, in reverse.  In theory, that "waist area" in front of the hips may reduce aerodynamic drag at extreme speeds and the turbulence may "straighten out" as air has a relatively slow reaction time at 400+ mph?  Instead of air impacting the hips at full velocity, it may roll away from them, at least in some small amount?  Like how sometimes a bump in an intake port smooths airflow around the valve guide.  At least I hope that's what they're doing. 

[robfrey]

I'm pretty sure this will not get better with speed.
I wish they would have just tuft tested this.
As many of us that have studied Aerodynamics understand, the Speed Demon is not optimal but apparently it's good enough. No car is optimal. I know the Carbiliner can be improved.
The body of the Speed Demon is an evolution. I believe the car was stretched in the "waste" area. I don't think the body was ever designed from scratch.
It would have been neat to see what design they would have come up with if they started from scratch. A huge part of building these cars is building the body. Since the molds were already made, it made sense to just rebuild the car and not design from scratch. Changes can easily be made to fix the stability problem and the car is one of the most successful if not the most successful car in the wheel driven LSR game.

[SPARKY]

I wonder how the turbo air inlets enter into the equation

[kiwi belly tank]

I seem to remember a conversation between George & Al that the design was conceived over dinner at the StateLine & drawn up on a napkin.
  Sid.

[tauruck]

The guy that does my aero is more qualified than most on the forum
and called the previous car "iffy''.
If NASA has designed that one or the current one they wouldn't look
the way they do.

[dw230]

Speed Demon is an evolution of Ron Main,s original Flat Fire lakester.

DW

[John Burk]

I'm sure Speed Demon's aerodynamic "faults" are tradeoffs to get down force .

[robfrey]

I'm sure Speed Demon's aerodynamic "faults" are tradeoffs to get down force .

Yes but what are talking about here does not help down force. In the grand scheme of things it will probably not mean much. We're just nit picking as there is nothing else to talk about.
I think Steve and his crew has done a great job of getting a great car back together again!