Big YF-12 RC Rocket glider for G-12 motors

Discussion in 'Rocket Boosted Gliders' started by burkefj, Feb 21, 2020.

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  1. Feb 21, 2020 #1

    burkefj

    burkefj

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    One day I'll sleep through the night and not wake up at 3am thinking about things like this....YF-12 interceptor version of the A-12/SR-71 family. Rarely modeled and I've never seen one as R/C let alone a rocket glider. This was an interceptor version with missile bay that wound up being used for testing the aim 47 missile and doing high speed/altitude testing for NASA. I believe the only survivor is in the USAF museum in Dayton.

    The chines were shorter on this design because of the large rounded nose cone that held the radar system. The R/C Rocket glider uses 9mm depron, bt80 tubing and is designed for 32mm glider G-12 reloads. Currently 18.2 oz with electronics, add, paint, nose weight and motor it'll be about 27 oz ready to fly. 32" wingspan, 59" long. About 1/20 scale. Construction is identical to my smaller 24mm kit version just upscaled by 1.5x which gives me 2.25x wing area and approx same wing loading and flight times

    Due to size and shipping cost, no plans for plans or kitting, sorry.

    86698906_564741094162538_8472830002277122048_o.jpg
     
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  2. Feb 21, 2020 #2

    cwbullet

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    Very nice. Go light with the paint.
     
  3. Feb 21, 2020 #3

    burkefj

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    Testors flat black rattle can which is one of the few paints that doesn't melt the foam covers pretty well one can will usually cover an entire small model and adds about half an ounce of weight, this one's a little bigger so took two cans. I've already budgeted that in my calculations.

     
    Last edited: Feb 22, 2020
  4. Feb 21, 2020 #4

    cwbullet

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    True, I was also concerned about added weight.
     
  5. Feb 22, 2020 #5

    BABAR

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    may sound crazy, but I have had good results with a black Magnum Sharpie (sounds like an oxymoron), adds very little weight. You have a lot of surface to cover, however.
     
  6. Feb 22, 2020 #6

    burkefj

    burkefj

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    Yeah, this would be all splotchy, there is no way to cover something this big with a sharpie, the beast is painted, added just under 1 ounce which is exactly spot on. Just waiting for some decals and motors to fly it.

    Frank
     
  7. Feb 22, 2020 #7

    burkefj

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    All finished up, just need decals

    IMG_20200222_145134286.jpg
     
    Last edited: Mar 2, 2020
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  8. Feb 22, 2020 #8

    aerostadt

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    With all these models I was wondering when you sleep. I guess it is before 3 AM
     
  9. Feb 24, 2020 #9

    burkefj

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    I got some great flights in on a G-25, G-12's and F-25's, all worked great

     
    Last edited: Mar 2, 2020
  10. Feb 26, 2020 #10

    Crawf56

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    Wonderful video work. But I fear you are picking up my bad habits (messing with old motors). o_O
     
  11. Feb 26, 2020 #11

    burkefj

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    Yeah, never again
     
  12. Feb 29, 2020 #12

    BABAR

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    nice save!
     
  13. Feb 29, 2020 #13

    burkefj

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    Originally I was hoping when I pulled back it would just settle flat and slowly burn out while sitting, it went into the smoke for a second, then I saw it balloon back up, so I stuck with it and after a couple seconds it quit and settled on the grass, no issue.

     
  14. Feb 29, 2020 #14

    burkefj

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    IMG_20200229_162752402.jpg Here she is all stickershocked up and finished!
     
    Last edited: Mar 1, 2020
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  15. Mar 5, 2020 #15

    burkefj

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    Some more videos, this time two on G-40's!

     
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  16. Mar 21, 2020 #16

    BABAR

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    Great flights and camera work (as usual;))
     
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  17. Mar 24, 2020 at 1:06 PM #17

    Weldo

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    Another very cool build! I've always maintained that the SR-71 and it's kin were among the most amazing machines ever made my man! The things these planes were capable of is just mind boggling and your model does them justice!

    In your first video, it seemed like the last motor had a strange liftoff, it was around 5:30 in the vid. It looked like it lifted slightly then really took off. Was that a different motor from the others or some kind of anomaly?
     
  18. Mar 24, 2020 at 1:09 PM #18

    burkefj

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    That was a 20 year old reload anomoly, i sent the vid to aerotech, Karl thinks shrinkage away from the casting tube allowed burning along the outside of the propellent, not just the end causing a double fast burn time after the initial ignition, I was fortunate the model was built strong.

     
  19. Mar 24, 2020 at 1:13 PM #19

    Weldo

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    Oh, I see. Thanks for the info!

    Hey I wanted to ask you, what's a good way to get started in these kind of flights? Like a decent starter controller unit and a smaller, lower flying kit? I've done a rocket glider a time or two but not one that had any sort of control.

    When looking for a controller is there a minimum requirement like number of channels and things like that?
     
  20. Mar 24, 2020 at 1:23 PM #20

    burkefj

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    The way I do them, which is to launch slightly tail heavy and then glide nose heavy without having to dump balast it requires a launch and glide elevator trim setting to be different. Most 2-5 channel radios don't have this ability of mixing to a switch, you can do it with trims but it's clunky to do while trying to control the model. Usually 6 channel and up have a flap setting which also includes putting a different elevator setting based on the switch position, I usually use this switch/setting to set my boost and glide, then I'm just steering after that is set right. The second thing you need for my models is elevon mixing which mixes roll and pitch to the two servos, also a function on 5 ch and up radios typically. On my website, dynasoarrocketry.com if you go under general instructions I have links to what I use for reference you can refer to, there are cheaper but I have not personally used them. My kits I make are fairly large, 38" long or so and fly to between 400-500 feet on average if you go straight up, a bit lower if you angle slightly, which isn't really that high, you can still see them well enough and it gives you enough glide time to get used to it. You really need to be comfortable with flying a fairly quick RC airplane first before you try a rocket glider because you can't shut off the motor if you get into trouble. There are lots of good beginner ready to fly planes out there, the radian is a good one.

     
  21. Mar 24, 2020 at 2:47 PM #21

    Weldo

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    Thanks for the advice! I'll check out your site.
     
  22. Mar 24, 2020 at 3:02 PM #22

    Weldo

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    This is neat stuff. I did some reading and have another question or two.

    Are you using any controls under boost, or is it hands off and it goes where it goes?

    Also would the flight of an elevon model be successful WITHOUT the roll/pitch mixing ability?
     
  23. Mar 24, 2020 at 11:56 PM #23

    burkefj

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    Yes, you are flying the model at all times, the only models that are true rocket gliders that are hands off(that don't eject balast or a booster) are never hands off really. Not major adjustments, but there is never no wind.

    There is no elevon without mixing, not sure what you are asking, if you are asking if you could fly it with just elevator control, then no, you need to steer not just adjust pitch.

    A good radio will last you for 20 years or more, get the best you can, not the cheapest.

    Frank


     
  24. Mar 25, 2020 at 12:33 AM #24

    Weldo

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    Thanks again! Sorry if I wasn't clear but I was wondering if a flight could work on just two channels. Something like channel one has an elevon setting for boost and an elevon setting for glide. Then channel two was simply roll adjustment for the glide stage. But I see now that flight with an elevon design would be impossible without elevon mixing.

    I've flown the Apogee SR-72 Darkbird and since it has no control, the elevons simply have a boost setting and a glide setting. What I was wondering was within that glide setting could the elevons be manipulated independently to get control of roll.

    So at apogee, channel one kicks the elevons into glide setting, which points the elevons upward toward the sky. Then channel two would allow the controlled lowering of one elevon at a time to influence roll.

    After thinking about it I don't expect it'll work. The servos would be fighting against each other I think. And at best the control would be crude.

    Sorry if I'm rambling or spouting nonsense but this was kind of a mental exercise for me! Rocket gliders are a cool way to add something more dynamic to the rocketry hobby.
     

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