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Thread: Glide Ratio

  1. #1
    Join Date
    Jan 2013
    Location
    Brady,TX
    Posts
    12

    Default Glide Ratio

    What is the glide ratio of a stock Pacer? Do wing extentions and wing tips help the glide ratio?

  2. #2
    Join Date
    Jan 2013
    Location
    Brady,TX
    Posts
    12

    Default glide ratio

    I guess no one wants to talk about glide ratio? As many PA 20 and 22 there with wing extentions, I figuer there has to be a reason for it.

  3. #3
    Join Date
    Jun 2008
    Location
    Roseville, CA
    Posts
    442

    Default

    Unfortunately, the crickets you hear probably indicate that none of the 6 people who post on these forums knows the answer.

    Kurt
    Ex-Vice President

    63' Colt

  4. #4
    Join Date
    Mar 2011
    Location
    Decatur, Texas
    Posts
    217

    Default

    Lift / Drag x height = Glide ratio

    There you go Kurt. My contribution.

    In all seriousness, I believe it does. If a wing extension increases lift and reduces drag, then it makes sense it would. But . . what do I know?

  5. #5
    Join Date
    Jun 2008
    Location
    Roseville, CA
    Posts
    442

    Default

    Perhaps if we had more than one Technical Advisor (an excellent one by the way) who would post on the forums (as opposed to referring to doing so as "playing on the computer", our membership could get timely answers to their questions.
    Ex-Vice President

    63' Colt

  6. #6
    Join Date
    Mar 2011
    Location
    Decatur, Texas
    Posts
    217

    Default

    What? You don't like my technical advice? That's hurtful Kurt. Just hurtful. Is my answer wrong? Just because you don't like droopy tips doesn't mean nobody should try to increase lift and decrease drag.

  7. #7
    Join Date
    Jun 2008
    Location
    Roseville, CA
    Posts
    442

    Default

    Rick, I have no idea what you're talking about. I'll chalk it up to humor.
    Ex-Vice President

    63' Colt

  8. #8
    Join Date
    Mar 2011
    Location
    Decatur, Texas
    Posts
    217

    Default

    Of course it's humor. My twisted, often misinterpreted version of humor. That's where I live.

  9. #9
    Join Date
    Jun 2008
    Location
    Roseville, CA
    Posts
    442

    Default

    Just checkin...
    Ex-Vice President

    63' Colt

  10. #10
    Join Date
    Mar 2012
    Location
    Sutter Creek
    Posts
    368

    Default

    OK, Boys! Don't make me stop this car!
    I have tried to find definitive data about the glide ratio of a SWP, but to no avail. What I do know, is that if you want to see a big rate of descent, maintain about 90 MPH with the power off. If you really want to suck the sheepskin off the seat, slow it down to about 55 MPH with the power off!
    The ability to put these planes just about anywhere you want, is one of their best attributes!
    Mark Ohlau
    1950 PA-20 N7744K
    KJAQ

  11. #11
    Join Date
    Oct 2005
    Location
    Graham, Texas
    Posts
    894

  12. #12
    Join Date
    Mar 2012
    Location
    Sutter Creek
    Posts
    368

    Default

    Quote Originally Posted by Steve Pierce View Post
    Great discussion! Thanks Steve.
    Mark Ohlau
    1950 PA-20 N7744K
    KJAQ

  13. #13
    Join Date
    Nov 2006
    Location
    Mason, Ohio
    Posts
    342

    Default

    There are some other threads on this forum on glide ration if you want to do the search. However, the glide ratio for the PA-22 as best I can find is between 8 and 10 depending on a lot of factors. A Tri-Pacer will have a lower glide ratio than a Pacer due to the increased drag of the nose wheel. Wing extensions and or wing tips that square off the wing tip increase the effective wing area, decreasing the wing loading and thus the induced drag and should increase the glide ratio. Vortex generators which increase the low speed lift should also help. Other factors such as whether the prop is windmilling or not will also have an effect. A windmilling prop will increase the drag. Your best bet to get an estimate of the glide ratio for your plane is to take it up on a calm day and test it. Cut the power and set up for best glide speed which is approximately 75 mph and record your decent rate and ground speed using a GPS. You can do this for various trim settings to determine the best settings for your plane. It should be a fun test. There is so much variability from plane to plane that it is almost impossible to establish a fixed number for glide ratio. That is probably why you don't see it published in any official documentation.

    Tom Anderson

  14. #14
    Join Date
    May 2007
    Location
    Victor, MT 59875
    Posts
    43

    Default

    I found the glide ratio on my pacer is approximately the same as that of the F-4 fighter I used to fly, 5 to 1.

  15. #15
    Join Date
    Mar 2012
    Location
    Searcy
    Posts
    66

    Default

    if you could just figure out how to get the same take off performance...

  16. #16
    Join Date
    May 2007
    Location
    Victor, MT 59875
    Posts
    43

    Default

    jwbruce, the takeoff performance between the F-4 and a SWP is no contest. The SWP wins. Takeoff roll for the F-4 was an average of 4000 feet and landing roll about the same. It is just before lift off that the F-4 takes over the SWP. Also, during takeoff the F-4 is burning 144,000 lbs per hour of fuel equaling about 22,000 gals per hour in afterburner. Naturally, we didn't use afterburner very long.

  17. #17
    Join Date
    Apr 2012
    Location
    Cary, NC
    Posts
    65

    Default

    i did a fairly extensive and moderately scientific flight test on my Pacer (O-320) and posted the results somewhere on these forums. Anyway, not to bore with all the details, but 75 mph was best speed for forward distance traveled versus altitude lost. Glided with windmilling prop, no flaps until last 300' as I slowed to 70 mph Vapp speed. In still air-equivalent conditions over a 2000' altitude loss: 3:14 time, 3.2 sm forward distance traveled, 750 fpm descent rate. Incidentally, I did a second test where you reduce power to idle/windmill, trim to level flight attitude then allow to descend. That equated to 75 mph IAS and 750 fpm, as well.
    BTW, standard wing tips, no VGs on my bird. All descents with 0 flap until last 300'. I have found that having a few extra mph for mom and the kids (70 vs. 68 or less) as you come in to touchdown at that fairly rapid rate of ground closure, makes a big difference in how much energy you have remaining to trade for up elevator to prevent a 'firm' landing. Come in too slow and you won't have anything left to flare with. Bungee test, anyone? Anyone? I'm am always amazed at how fast this plane falls out of the air.
    Slipping the surly bonds of Earth...

  18. #18
    Join Date
    Apr 2012
    Location
    Cary, NC
    Posts
    65

    Default

    Here's my original thread reply "Best Glide, V speeds" http://forum.shortwingpiperclub.org/...8036#post28036
    Slipping the surly bonds of Earth...

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