Added: 5 years ago
From: stuman1159
Views: 17,604
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  • Ok really stunman the fins were made out of fiberglass. This is a Quantum Leap model rocket from Public Missiles. The fins were fluttering as they would call it since it is going well past mach. Its crazy to believe that they would even bend like that. Btw supersonic speeds are Mach 1.2 and up. Mach 1-1.19 is transonic

  • okay that was BLOODY COOL

  • the warping fins are a bi-product of the type of camera recording sensor and vibration most likely from speed...take a picture of a rotating fan with your phone camera and you will see the same effect but in a still picture....

  • For those that want to know... That is a PML Quantum Leap model. The fins are G10 fiberglass with a carbon fiber overlay. What you are seeing in the video is caused by the conversion process. Those fins didn't do that. They can't.

  • 5/5, this is the most amazing sound barrier video I've ever seen, you can clearly see it's impact on the fins and the immense g-force implied after firing

  • I love the fins ! 0:09

  • Yeah, Fighter Pilots say the same thing. There is no Sonic Boom heard in the cockpit. You have to be on the outward - "slow" - side of the wave to hear it.

  • What you see in the vid is an illusion created by the digital conversion process.

    Those fins are G10 fiberglass with a composite lay-up to the airframe. They are not capable of doing what is seen in the video. It would shred first.

    K550+K185+QL2= ~13K AGL.

  • kind of like holding a pencil between to fingers and shanking it so that it looks like rubber. I agree but I still belive that is the point of sonic. I think that as the cone and camrea punch thru the barrier that is what caused the vibration u discribe or it could of been that the tail had not pass the barrier and for a split sec it was still subsonic.

  • Yeah, flutter is not recomended

  • What altitude did that reach? Any idea?

  • Im not sure how high it got but look at the vid I thing I saw the blackness of space. but naw could not be.

  • Really, really, really, really, really, really, really, really, really, really, really fuckin high.

  • I saw this a while ago. One question..if its supersonic shouldnt there be a sonic boom as it passes the sound barrier?

  • Sonic Boom would only be apparent to a ground observer. As the sound waves collect behind the object approaching the speed of sound they build up and when it surpasses the sound barrier is when you hear the boom, but you wont hear it if your in the object.

  • Ok..thank you! That makes sense!

  • @JetJockey87

    ...just a correction in front and not "behind" the object. ;)

  • What material are the fins made out of?

  • I want to know how big the rocket was, what size motor was used, and how high it went. Looks like there were two other rocket as well. Correct?

  • Did it airstart another motor?

  • WOW! I'd give it a hundred stars if I could!

  • The post below uses "c" but I meant "C" = SS = Speed of Sound, 1130 fps. .8Ma<Transonic<1.2Ma

  • I'm guessing that the altitude/apogee was approx. 20,000' and avg speed during burn was 1000 fps, with a max speed of 1350 fps on final stage with max thrust prior to burnout. The fins remained motionless, suggesting it was 7075/T6 Al...not many synthetic materials could withstand that force. I would not be surprised if the tube was thin wall T6. The velocity, integrity, & stability make this a VERY impressive launch.

  • The max velocity can be seen/heard at 00:11 & likely it was a little over "c". At 00:10 c/1130 fps was reached which is seen when the rocket goes transonic riding in its own sound wave & causing distortions, & a wild, rapid spin. 4 substantial fins are noted. I want this!

  • It could have been harmonic resonance causing the fins to vibrate like that couldn't it?

  • That was fast!!

  • Simply wonderful!!!!!!!!! At what altitude it is arrived?

  • Hm...That was fast!

    Does anyone knows what was the SPEED and ALTITUTE? I wondering...

    Thanks!;o)

  • nealy got into space!

  • wow..that is impressive...5/5 stars

  • what is the thickness of the aluminium u are using on those stabilising fins?

  • I'd guess the fins warp from air turbulence when the rocket goes transonic. I doubt the warping is due to the camera, since stuff around the fins doesn't seem to warp, and the fins seem to have gradient lighting in accordance with their shape.

  • I don't think the fins are actually warping. I've flown a lot of r/c airplanes with video cameras on board, and on occasion vibration will make waves in the video. Besides, if the fins are aluminum, they would stay warped. Unless they are made by Rubbermaid!

  • That sounds right to me...I don't know exactly what the fins were made of...could've been some type of plastic.

  • @stuman1159 There is no material that could warp so. It's the camera vibrating,maybe caused by passing the sound barrier.

  • @stuman1159 Not only do you not know that, you don't know that supersonic speeds are quite a bit over mach 1. More like 1.05 and up.

  • @flyparks 2 posibilities

    1. Flutter, the aluminium fins are being elastically twisted (possible even with this amount of distortion) due to aero elastic effects

    2. the density change due to the shock wave is causing a lensing effect which make the fins look bent. the "flapping" is caused by the movement of the shock wave forward and aft. as the rocket accelerates only way to tell would be to put strain gauges on the blades (and a DAQ on the rocket) or perhaps pattern matching from the ground.

  • what are the fins made of?

  • Aluminum

  • pls tell me what did you use as a poropellant

  • dude this is the best video ever. I watch it at least once a day on average.

  • holy crap! Did you see those fins?!?

  • HOLY SHIT! Nice, What modle engine was it? O? M? what?

  • wow how do you make one of those engines, gunpowder or some thing else?

  • kno3 and sugar works good.....look it up

  • You buy them.

  • That is truly brilliant!

    Amazing man.

    How much work to get a rocket made like that ?

  • Wonder why the fins dont warp again as it comes back below transonic speed.

  • the parachute probably scrubs off a lot of airspeed.

  • Parachutes slow things down, that is the idea...

  • How high was that thing

  • Hella High....

  • 2 stages...20,000+ ft. AGL

  • Whoa...how high up is that? And how many stages? Just two?

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