Holverson Swinger RG – resurrection of a nostalgic classic

Discussion in 'Rocket Boosted Gliders' started by Rktman, Jan 18, 2019.

Help Support The Rocketry Forum by donating:

  1. Feb 21, 2020 #91

    Rktman

    Rktman

    Rktman

    Eric Noguchi

    Joined:
    Mar 5, 2017
    Messages:
    874
    Likes Received:
    43
    As far as I can tell everything is in proper alignment when the wings deploy. I did try some hand tosses immediately after it's initial flight and it glided nice and level, which is why I'm at a loss to figure out what's up with it when it's launched. After it lawn-darted on its second flight I'm going to have to rebuild the motor pod/piston and retry it with a few grams of nose weight to see what it does.

    Serendipitously I was gifted with another Swinger kit by a fellow club member so I'm going to build that one completely stock and see how it flies. I'll be able to compare the two to see if I can spot any differences at all in the lifting surfaces or alignment of components. Hopefully I can discover the culprit, which would make for a very valuable learning experience.
     
  2. Feb 21, 2020 #92

    Rktman

    Rktman

    Rktman

    Eric Noguchi

    Joined:
    Mar 5, 2017
    Messages:
    874
    Likes Received:
    43
    The actual "1st" flight never left the pad—the glider got hung up on the launch rod but the wings did deploy fully, about the only thing successful about the aborted attempt lol. You're right that aerodynamic drag may be a factor here, so maybe I should try throwing it hard with the wings folded back in launch position to see what happens. There's already quite a bit of tension in the elastic but I could also try tightening them up a tad as well.
     
  3. Feb 23, 2020 #93

    Rktman

    Rktman

    Rktman

    Eric Noguchi

    Joined:
    Mar 5, 2017
    Messages:
    874
    Likes Received:
    43
    Started work on replacing the motor pod and noticed that the wings deploy with so much force, they've left a dent in the fuselage. Hmmm...it's only between 1/32" and 1/16" deep but I'm wondering if it hyperextends the wings just barely enough to cause the stalling? Grasping at straws at this point, but the wing's root edges appear to still be perpendicular to the fuselage so I can't be sure. At any rate, the wings definitely are fully deploying. I'll need to either go with a slightly longer elastic or glue on a small square of 1/64" ply to protect any further deepening of the dent.
     
  4. Feb 23, 2020 #94

    Ez2cDave

    Ez2cDave

    Ez2cDave

    Well-Known Member

    Joined:
    Jan 18, 2009
    Messages:
    3,198
    Likes Received:
    706
    Eric,

    Great observation !

    My theory is that the "over-deploying" wings are giving you a different CG location, relative to the Average Chord of the Wings. If that is happening, trimming would be very inconsistent. Reinforcing the area and re-establishing correct alignment should stop the problem.

    Dave F.
     
  5. Feb 24, 2020 #95

    Rktman

    Rktman

    Rktman

    Eric Noguchi

    Joined:
    Mar 5, 2017
    Messages:
    874
    Likes Received:
    43
    Didn't think of that, thanks! With the original motor now torn off, I'll have to remember not to repair the dents until after it's back together again so I can test that theory. Hope it was the cause of the stalling, would sure like to solve this mystery.
     
  6. Mar 10, 2020 #96

    Rktman

    Rktman

    Rktman

    Eric Noguchi

    Joined:
    Mar 5, 2017
    Messages:
    874
    Likes Received:
    43
    Update

    It’s been awhile (new builds tend to get priority over repairs, which tend to be “when I get around to it”). Per the suggestion from Ez2cDave in another thread, I replaced the balsa piston with an 18mm coupler from Mach 1 Rocketry. Steve Skinner from Mach 1 was kind enough to include a bunch of thick G10 ‘glass rounds that are punched out when creating ‘glass centering rings for his kits. I used it to seal the ejection end of the piston and used a standard ply block to close off the forward end where it slams up against the piston stop inside the motor tube. The piston assembly should now be far more heat proof and resistant to ejection damage than the balsa version.


    IMG_4187.JPG

    IMG_4190.JPG

    I sanded down the burnt original balsa piston so it would fit inside the coupler. Probably didn’t need to but it helped center the holes I needed to drill for the control rod, and helps hold the rod snugly inside the ‘glass coupler so it won’t wander until I can install it in the motor pod and anchor it in place with a little thin CA. A little bit of JB Weld on the ejection end and it’s ready to go.


    IMG_4194.JPG

    Motor pod’s ready to be installed on the glider pylon. Should be interesting to see where the CG falls with the marginally heavier piston. It may save me the need to add nose weight to stop the stalling. I’ll also be repairing the dent in the fuselage where the wing roots slap up against it and seeing if that was changing the wing position or shifting the CG just enough to cause the porpoising. Probably won’t get a chance to trim or test fly it anytime soon though.

    IMG_4199.JPG
     
  7. Mar 10, 2020 #97

    Ez2cDave

    Ez2cDave

    Ez2cDave

    Well-Known Member

    Joined:
    Jan 18, 2009
    Messages:
    3,198
    Likes Received:
    706
    Eric,

    Looking good . . . That ought to solve the piston issues !

    Steve Skinner is a really nice guy and a "class act". I've spoken with him on the phone several times ( long conversations - LOL ! )

    Dave F.
     
  8. Mar 10, 2020 #98

    Rktman

    Rktman

    Rktman

    Eric Noguchi

    Joined:
    Mar 5, 2017
    Messages:
    874
    Likes Received:
    43
    Steve's a great guy, really enjoyed talking with him, that hour passed quickly. Interesting how he and his biz partner got into MPR/HPR and then subsequently started Mach 1. Couldn't resist buying my first 'glass kit (18mm Alien Interceptor).
     

Share This Page

Group Builder