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Thread: Aerodynamic modifications

  1. #71
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    Default Re: Aerodynamic modifications

    Quote Originally Posted by Curt_B View Post
    Thanks. Have an even more oily Strega photo more local to the scoop, Pulled it off the web, but don't know if somebody would object to me posting it here. There's a lot more going on with Strega on the backend. Was this the fast Dago Red scoop with the modified splitter in Fig 16 of;

    http://www.warbirdaeropress.com/NewG...ing/index.html
    There's some guys who attend this site with much greater knowledge of Dago's history. Specifically that looks like the very early Dago(1982), but I do remember in '93 it had a different set up(very squarish inlet). Must be sometime during the 90's they changed it to the much more efficient looking splitterless small inlet design. The afterbody looked cleaned up also. One other thing I always liked about Dago Red is the stock looking horz. stab. No clip. Chopped edges don't look all that efficient. Would one square off the main wing and expect it to be efficient? ...Trivial(since it's the stab), I know...

  2. #72
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    Default Re: Aerodynamic modifications

    Quote Originally Posted by RAD2LTR View Post
    Here are a few shots I took showing some leaks of some sort. The streams do take an interesting split at the scoop


    you can't see much in the way of leaks with this but it shows the underside nicely.


    Here is an interesting look at the scoop and strake profiles of Strega, Voodoo and PM.




    Will
    Very cool! Voodoo actually doesn't look bad. Thanks for those photos. Looks like some kind of boundary layer diversion around the scoop for sure on Strega. So does that indicate clean airflow to the tunnel?

  3. #73
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    Sep 2013
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    95

    Default Re: Aerodynamic modifications

    Thanks for the under belly photos. Haven't seen some of them. You can tell the difference between the scoops. Looks like Strega's is generating a little stagnation around the lip and it's causing the boundary layer air to go around. Might need a little touch-up aerodynamically.


    Quote Originally Posted by John View Post
    There's some guys who attend this site with much greater knowledge of Dago's history. Specifically that looks like the very early Dago(1982), but I do remember in '93 it had a different set up(very squarish inlet). Must be sometime during the 90's they changed it to the much more efficient looking splitterless small inlet design. The afterbody looked cleaned up also. One other thing I always liked about Dago Red is the stock looking horz. stab. No clip. Chopped edges don't look all that efficient. Would one square off the main wing and expect it to be efficient? ...Trivial(since it's the stab), I know...
    The tail's making a lot of lift at these speeds all the way around the course. Induced drag is a function of span, as opposed to aspect ratio, and the short span of the tail coupled with it's high downward lift is generating a significant amount of tail induced drag. Never understood why everybody shortened their tails, unless their analysis says otherwise. I suspect the Mustang guys did it because it was a simple mod, and maybe didn't think it through.

    Link is some simple aero principles, including wing tips;

    http://www.zenithair.com/stolch801/design/design.html
    Last edited by Curt_B; 10-11-2013 at 10:04 PM.

  4. #74
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    Default Re: Aerodynamic modifications

    Quote Originally Posted by Curt_B View Post
    Roundy spinners are best because the air flowing around them accelerates early and the pressure integration produces a thrust. The pointy spinner delays the acceleration toward the back end of the spinner and can see how that would incrementally lower the pressures at the 'smile'.
    Thanks for answering a question I have been meaning to ask here and has perplexed me for years. One would think the pointy spinner would be more aerodynamic not thinking about how it affects intake pressure to the "smile"and its toll on MP. Makes total sense now and I understand why they use the stocker. The pointy ones though, to quote Jimmy Leeward, "Sure look sexy." They really do put the final hot-rod racey touch on a Mustang.
    Last edited by hm66sk; 10-12-2013 at 06:30 PM.

  5. #75
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    Default Re: Aerodynamic modifications

    Quote Originally Posted by RAD2LTR View Post
    Speaking of interesting mutations of the P51, MA2 had some creative ideas for lowering drag such as the NACA ducts for both the carb intake and for the radiator scoop. According to the book "Griffon Powered Mustangs" once they had a few things sorted out, both worked very well. Will
    Awesome thread. Love this technogeek ****. Lets me live vicariously through you guys that are there. Tsunami started with a NACA scoop then switched to a standard intake ala P-51A. Apparently the NACA didn't work so well for them. Sandberg chose a downdraft system like the Griffons though right? Any info on both these changes and why?

  6. #76
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    Default Re: Aerodynamic modifications

    I really need to read the entire thread before I ask a questions that have been answered already.

  7. #77
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    Default Re: Aerodynamic modifications

    Quote Originally Posted by hm66sk View Post
    Awesome thread. Love this technogeek ****. Lets me live vicariously through you guys that are there. Tsunami started with a NACA scoop then switched to a standard intake ala P-51A. Apparently the NACA didn't work so well for them. Sandberg chose a downdraft system like the Griffons though right? Any info on both these changes and why?
    The book "Griffon-Powered Mustangs Volume 1" talks about this, hence the reason I mentioned it. They specifically mention the fact that Tsunami's didn't work because it was feeding turbulent air into the carb due to the carb sitting too close to the 90 degree turn from the inlet. They went on to say that it did work well on MA2 because the carb sat lower, further away from the 90 degree turn allowing the air to smooth out before entering the carb. That said, I can't say the book is right, and if anyone who actually was part of either of the two projects says otherwise, I'd believe them since they were there first hand.

    The MA2 bit got me thinking/wondering if the PM guys had something like this idea up their sleeve for a future mod, assuming it worked as stated with a Griffon. IF what is already there produces more power than drag and a NACA version would cut the drag, but power as well, there is no reason to try it. (Speculating here)

    I'll be honest, I'm absolutely fascinated by aerodynamics and the art that is designing things to go faster. I know there was tons of research done in the late '40s on P51s and other things. As the PM guys found out, a reprofile of the prop blades can yield big results. (Also makes me wonder why none of the other teams such as Red Barron, MA2, and even the Whittingtons tried it. Perhaps it was thought of, but the technology to do it wasn't there at the time.) It sort of makes me wonder what else is sitting in an archive somewhere that has been long forgotten that could yield other great results especially if done using todays technology.

    Will

  8. #78

    Default Re: Aerodynamic modifications

    No NACA for PM. I hate the abuse of NACA scoops.

  9. #79
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    Default Re: Aerodynamic modifications

    Quote Originally Posted by Wild Bill Kelso View Post
    No NACA for PM. I hate the abuse of NACA scoops.
    NACA scoops work fantastic as long as they are built the right size with the right formula (you can't just eyeball the dimensions) and use them in the right environment.

    Constant-g, constant-turn environment is not the 'right' environment.

  10. #80
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    Default Re: Aerodynamic modifications

    Quote Originally Posted by Wild Bill Kelso View Post
    No NACA for PM. I hate the abuse of NACA scoops.
    I guess that answers that pretty soundly. You guys have a good idea of what does work, what might work, and what doesn't work. I'd also guess you have looked at what has and hasn't worked in the past with similar setups and made up your mind what you want to try and what you don't. I figured you had reasons why you didn't go the NACA route from the get go, otherwise it likely already would have been done. Since apparently it doesn't' work well in a constant G constant turn environment, it makes perfect sense why you wouldn't want to use one.

    Will

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