Aerodynamic vs. vehicle stabilty

[jl222]

JL222
   Do you know the name of that video? I figured there would come a point where that wouldn't work considering 1/8th mile speeds are much slower than LSR speeds, i was just wondering if i could slide forwards up to the fairing to help fight some of the high speed handling problems.
                                                              -Chad-

 No, but I'll try to find out and don't take my comment about jumping off to seriously

              JL222

[jl222]

JL222
   Do you know the name of that video? I figured there would come a point where that wouldn't work considering 1/8th mile speeds are much slower than LSR speeds, i was just wondering if i could slide forwards up to the fairing to help fight some of the high speed handling problems.
                                                              -Chad-

  Chad... google....[Death of a top fuel harley] also videos of Ron Cooks get offs at Muroc and El Mirage and Korry Hogans crashes.

                 JL222


                           

[healewis]

It's a shame really, I got to page 5 before posting and felt I had reached the pint of "go no further". The start of the topic got my interest immediately. I was looking forward to reading about aerodynamics and the experiences that many of you who have "been there", "done that" and "worn the shirt", had to say on this topic. A chance to participate in a master-class! Unfortunately, this topic has strayed away from the initial intention to develop into the usual forum discussion where one gets offended and has a go and others follow suit. The Author of the topic did not set out to offend anyone but to simply gather opinion and fact of experience for which everyone would benefit. So why be offended? Pitty

Paul   

[healewis]

Re....the front is pulled around

To clarify...the tire rolling with weight and the coefficient of friction on the salt is what pulls the front end around at spin initiation. After the spin starts and the tire starts sliding aerodynamic forces get involved with the kinetic friction. Spin initiation is the rear kicking out and creating a steering angle.

I have always greatly enjoyed talking with you. . Usually on your favorite piece of real estate. . IMPOUND!    I think you have identified an incredibly important subject. I'm trying to understand what some may consider finer points. But to keep needling away at this will only invite negative feedback from others which breaks down any further education. I’ll buy you a cup of coffee at the Red Flame so we can share some additional thoughts. After all, The Red Flame is not too far from where you are usually parked!


Something I’m struggling with is; once the spin is initiated and the CG is now accelerating around the steering angle, how do you react the CG momentum? With rolling rear tires (i.e. some traction) and zero-friction-sliding front tires (via full braking) I can understand the effect you mention. But if the front tires are turned into the direction of travel and rolling you might cancel out some of the CG momentum. Not sure though . . . maybe it’s the CG’s arm from the pivot point . . . the location of the CP . . . other?  Thanks for introducing a thought-provoking perspective.

Wanted to leave the topic but had to read on I think I understand the theory behind locking the front wheels>. the CG is,at the point of spin moving faster than the front of the vehicle. Once the front wheels start to skid, they begin to increase in speed thus the correction is possible. I think?

Paul

[SPARKY]

I have been following another team that has not posted  they have a roadster that will, no "wants" to spin one way in the wind tunnel and not the other---they are thinking that they are dealing with some issues as to how the chute pack influnces the "aero"

[jl222]

It's a shame really, I got to page 5 before posting and felt I had reached the pint of "go no further". The start of the topic got my interest immediately. I was looking forward to reading about aerodynamics and the experiences that many of you who have "been there", "done that" and "worn the shirt", had to say on this topic. A chance to participate in a master-class! Unfortunately, this topic has strayed away from the initial intention to develop into the usual forum discussion where one gets offended and has a go and others follow suit. The Author of the topic did not set out to offend anyone but to simply gather opinion and fact of experience for which everyone would benefit. So why be offended? Pitty

Paul  

  Paul... are you talking about Blue's post? After more than 60 years,you don't think that having to prove aero stability for motorcycles over 200 mph and cars over 300 mph might offend someone, when an unstreamlined motorcycle has gone over 270 and a car [ Lindsleys and Liggitt] 333 avg this with a top speed over 340+. No roadster is going to prove aero stable over 300. This would outlaw all cars over 300 most bikes all roadsters and most lakesters and some streamliners and you don't think we should be offended?

           JL222

  P.S. Do you think he was gathering opinion and facts talking to our senior official?  

[saltfever]

Wanted to leave the topic but had to read on I think I understand the theory behind locking the front wheels>. the CG is,at the point of spin moving faster than the front of the vehicle. Once the front wheels start to skid, they begin to increase in speed thus the correction is possible. I think?
Paul

Good point, and makes sense, Paul. Same effect with a swinging pendulum. If you move the pivot point in the direction of travel you cancel out the momentum or swing and stop the pendulum.

I am kind of disappointed in Blue's participation here. I was assuming he is a PhD Aerodynamicist from his postings and his statements of aircraft design prowess. He started the subject and I anticipated he would kind of act like a moderator and jump in from time to time to clarify, or add some good science or engineering, to the issues. He has mentioned a few platitudes like quarter chord or yaw neutral point, or the Center of Pressure instability. However, when sincere questions result about these statements they are completely ignored. I have had no response to my posts #3 and #19. He has also made assumptions about a CG location on a vehicle (and continues to stick to that assumption) without knowing any of the individual masses or their moment. He has calculated the CG in his mind, completely ignorant of the facts. I want to learn from everybody. But to be valuable the learning process must filter out B+S. He has made me think about some very important points (that I am appreciative for) but is lacking on follow-through. I am off to Bonneville now so will be silent the next 10 days. Hope to see you there Mr. Blue . . .

[healewis]

It's a shame really, I got to page 5 before posting and felt I had reached the pint of "go no further". The start of the topic got my interest immediately. I was looking forward to reading about aerodynamics and the experiences that many of you who have "been there", "done that" and "worn the shirt", had to say on this topic. A chance to participate in a master-class! Unfortunately, this topic has strayed away from the initial intention to develop into the usual forum discussion where one gets offended and has a go and others follow suit. The Author of the topic did not set out to offend anyone but to simply gather opinion and fact of experience for which everyone would benefit. So why be offended? Pitty

Paul   

  Paul... are you talking about Blue's post? After more than 60 years,you don't think that having to prove aero stability for motorcycles over 200 mph and cars over 300 mph might offend someone, when an unstreamlined motorcycle has gone over 270 and a car [ Lindsleys and Liggitt] 333 avg this with a top speed over 340+. No roadster is going to prove aero stable over 300. This would outlaw all cars over 300 most bikes all roadsters and most lakesters and some streamliners and you don't think we should be offended?

           JL222

  P.S. Do you think he was gathering opinion and facts talking to our senior official?   

HI JL222,

I can appreciate your opinion but, as I read it, Blue was, bringing a valuable topic up for discussion. I would not be offended if a young apprentice told me how to form sheet steel to make a vehicle panel, I would look at what he was trying to tell me then see if I could benefit from his information. If I thought I could not, I would offer my opinion to him.
 
Regardless of our experience there is always new technology and innovative ideas on the horizon, and with the aerodynamic  brain power within this thread alone, together, we could maybe, find an answer or two to solve those niggling issues that prevent us from achieving our ultimate goal. It's easy to feel offended and I appreciate that but would it be possible to respond with facts that answer the questions put forward for discussion. 

If it wasn't for people like Blue, then the forums probably would not exist because everyone would be reluctant to offer an opinion for fear of being scalded due to unintentionally insulting anyone. 

Cheers and good health 

Paul 

[jl222]

   As far as proving aero stability and facts.
   Which aerodynamist are you to believe, as porkpie says ask 10 aerodynamist and get 10 different answers.
   As far as Blues theories, unstreamlined bikes at 270 and passenger car at over 340 proves him wrong by real racers
   What do you think of a rapid lane change at 600 mph as suggested by an aerodynamist?
   The same person suggested I try it at high speed in the 222 car to test aero stability. I replied, suggesting that showed his basic missunderstanding of traction on salt of rear wheel drive vehicles.
  As far as responding with facts go back and look at all the post with unanswered questions to Blue.
  Its as though he started this thread so he can sit back and say [I told you so]
  Paul who is your aerodynamist?

 JL222

                JL222

[Oldanontheway]

I believe the racers, the record holders,the people who love this venue should keep on racing. Blue has caused nothing but controversy and dissension, with his hypotheses.   Let him argue and speculate with the other 9 aerodynamicist, who think they know it all.

old...



He might even be a guv'mint spy.

[saltfever]

Is this "Blue" i.e., Eric Ahlstrom?
(Edit . . . ) link has been deleted, with my apologies, based on post #162.

[Rick Byrnes]

Isn't that interesting.

No credentials at all in aero engineering.

BSME is something I respect, and knowledge of fluids is very likely, but not enough to tell SCTA that flat bottom car/bike liners are so unstable they should be eliminated.

I think I'll stick with my "real" Aerodynamics Engineer who has a lifetime of study of the aerodynamics of cars.

OH, isn't Howard Nafzingers old car, now Charles Nearburg "Spirit of Rhet" a flat bottom car?

Sorry I just can't resist.

Everyone be safe on the salt.  I'm prayin for good weather, salt, and racers luck for you all.

[bbarn]

That is not the same Eric.

[healewis]

   As far as proving aero stability and facts.
   Which aerodynamist are you to believe, as porkpie says ask 10 aerodynamist and get 10 different answers.
   As far as Blues theories, unstreamlined bikes at 270 and passenger car at over 340 proves him wrong by real racers
   What do you think of a rapid lane change at 600 mph as suggested by an aerodynamist?
   The same person suggested I try it at high speed in the 222 car to test aero stability. I replied, suggesting that showed his basic missunderstanding of traction on salt of rear wheel drive vehicles.
  As far as responding with facts go back and look at all the post with unanswered questions to Blue.
  Its as though he started this thread so he can sit back and say [I told you so]
  Paul who is your aerodynamist?

 JL222

                JL222

My opinion is irrelevant, what is relevant though is that you feel he is talking through the top of his head and that opinion is fine and the right of anyone else on the forum. All I was suggesting is, rather than gathering a lynch mob cause "were gonna have a hanging", Offer some genuine facts as to why he is wrong then people can use those fact to assist them with their projects.

Once the arguing starts, the topic goes to pot and the discussion results in a waste of server space and may as well be deleted. I have no intention of standing up and telling anyone on these forums that they are doing it wrong, I'm here cause I want to learn about aerodynamics and vehicle stability, I am here because I want to design and build a vehicle that will travel across the face of the earth at over 1000 mph and the back again, with one sole purpose in my mind and that is, at the end of it, the driver can climb out un aided and say "We did it"!

As for my aerodynamist, I am not going to divulge and information re: any of the personnel involved in The Bullet Project at the moment. I designed the car and CFD testing will commence in due course. I can say that our aerodynamist was the chief CFD engineer for a major Formula One team and has recently left Formula One just last year.

We are 10 years + behind all the other teams out there in this challenge. Only one of them has acknowledged the fact we are going for 1000 mph (thank you Waldo) the rest are pretending we don't exist. My site has links to all the other players websites I get none in return. Thats why I'm playing my cards close to my chest. All up to date info will be on our website.

Cheers

Paul   
 

[blackslax]

My opinion is irrelevant, what is relevant though is that you feel he is talking through the top of his head and that opinion is fine and the right of anyone else on the forum. All I was suggesting is, rather than gathering a lynch mob cause "were gonna have a hanging", Offer some genuine facts as to why he is wrong then people can use those fact to assist them with their projects.

Once the arguing starts, the topic goes to pot and the discussion results in a waste of server space and may as well be deleted. I have no intention of standing up and telling anyone on these forums that they are doing it wrong, I'm here cause I want to learn about aerodynamics and vehicle stability, I am here because I want to design and build a vehicle that will travel across the face of the earth at over 1000 mph and the back again, with one sole purpose in my mind and that is, at the end of it, the driver can climb out un aided and say "We did it"!  
 

Hear Hear,
I read a lot on this site and post very little.  I have to concur that the linch mod mantality it pointless and detracts from forward momentum.  If 1212 and JL222 don't like the discussion, it is very simple to skip over the string when "showing unread posts since my last visit", or start your own string named "Why aero vs. vehicle stability is a crock of sh&#" or "aero vs. stability linch mod string".  Let the rest of us discuss the matter in a forum that moves the conversation forward.  And this shooting the messanger because you don't like the message is real junior high crap.  BLUE is just trying to get some ideas flowing around in people's heads.  If you do not agree with position, state your opinion about the discussion.  If you want to tear down the person making the arguement, get out your tape measure, lay yours out on the table, and show us what you got.