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  #11  
Old 03-19-2009, 08:05 AM
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Originally Posted by Doug Sams
In what way? Do you find it horrifying? Or pornographic?

Doug

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Intruder, you'd better think before you answer him, or else your supply of tubes and balsa will dissappear.
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  #12  
Old 03-19-2009, 03:29 PM
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Originally Posted by tbzep
Intruder, you'd better think before you answer him, or else your supply of tubes and balsa will dissappear.


............................
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  #13  
Old 03-20-2009, 04:04 AM
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Quote:
Originally Posted by Doug Sams
Yes. A nuclear T-motor did this to one of my Zoomies Doug.


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I haven't had a chance to test it in flight yet, but on my over-the-winter builds that eject their motors (Zoomie, Sparrow, Semroc Hawk), I've been coating the bases of their nose cone shoulders with yellow wood glue. If that turns out to not be sufficient to prevent nose cone blow-throughs, perhaps a coat of epoxy and/or a thick card stock disc cemented to the base will do the trick.
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  #14  
Old 03-20-2009, 10:41 AM
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Quote:
Originally Posted by blackshire
...perhaps a coat of epoxy and/or a thick card stock disc cemented to the base will do the trick.
A disc is the best bet. Epoxy, or any other adhesive without some sort of added fiber or material, adds mostly weight and not much strength.

Doug

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  #15  
Old 03-24-2009, 02:42 PM
Jeff Walther Jeff Walther is offline
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Quote:
Originally Posted by BEC
Here's a little Google Earth and Powerpoint illustration.....


Hey, thanks! That's very illustrative and sheds what might be some light on my one-flight-Mosquito problem. I keep watching the ejected engine all the way to the ground, instead of the rocket. Then when I look where the rocket should be (I think) I can't find it. But from your illustration, I bet those poor Mosquitoes are a lot further in the opposite direction from the engine, than I thought.
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  #16  
Old 03-24-2009, 11:30 PM
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Quote:
Originally Posted by Jeff Walther
Hey, thanks! That's very illustrative and sheds what might be some light on my one-flight-Mosquito problem. I keep watching the ejected engine all the way to the ground, instead of the rocket. Then when I look where the rocket should be (I think) I can't find it. But from your illustration, I bet those poor Mosquitoes are a lot further in the opposite direction from the engine, than I thought.


What has more mass - a spent engine case or a Mosquito? Think about equal and opposite forces (the ejection charge acting on both) and good ol' F=MA. Yeah, you might want to be looking a little further the opposite way from the trajectory of the engine case.

In the case of the Gyroc, once the flaps are deployed it comes down very slowly and so the breeze will carry it a good distance. I imagine a Mosquito comes down a little faster so will drift back downwind less (assuming an ejection past apogee).
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  #17  
Old 03-25-2009, 12:11 PM
Jeff Walther Jeff Walther is offline
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Quote:
Originally Posted by BEC
What has more mass - a spent engine case or a Mosquito? Think about equal and opposite forces (the ejection charge acting on both) and good ol' F=MA. Yeah, you might want to be looking a little further the opposite way from the trajectory of the engine case.


Yep, the Mosquito probably weighs less than the engine casing so it should have more velocity initially. However, if it is unstable, it may have a lot more drag. Pesky atmosphere makes projectile motion calculations difficult.

What do you think? Is a Mosquito with no engine but with a high initial V going to be stable long enough to fly far away from the ejection point?

Quote:
Originally Posted by BEC
In the case of the Gyroc, once the flaps are deployed it comes down very slowly and so the breeze will carry it a good distance. I imagine a Mosquito comes down a little faster so will drift back downwind less (assuming an ejection past apogee).


From what I can see, the ejection seems to be right at apogee with the 1/4A3-3T. At least, the rocket is laying over horizontal when the ejection occurs. This is a large part of the problem. All the velocity imparted by the ejection is in the horizontal plane. And for some reason, it's always easier to spot the engine casing--maybe it trails a little smoke or something. I had been thinking that it's moving faster and the eye is drawn to faster moving objects but the physics says not, unless the Mosquito is really draggy right after ejection.

I'll probably get this figured out when I'm on my last Mosquito kit. I have three built ones left (if I count the one from my childhood) and about ten more kits.
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  #18  
Old 03-25-2009, 02:49 PM
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Quote:
Originally Posted by Jeff Walther
And for some reason, it's always easier to spot the engine casing--maybe it trails a little smoke or something. I had been thinking that it's moving faster and the eye is drawn to faster moving objects but the physics says not, unless the Mosquito is really draggy right after ejection.
It's because the motor case is tumbling - it's easier to see and it falls as slow or slower than the rocket, which comes in ballistic - lawn dart. Which, btw, is why you'd rather be hit by the motor instead of the rocket

Anyway, too many times my eye has been drawn to the tumbling case and not the rocket I almost always fly MicroMaxx in Mosquitos and Quarks and avoid the long searches

Doug

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  #19  
Old 03-27-2009, 04:07 PM
Jeff Walther Jeff Walther is offline
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Quote:
Originally Posted by Doug Sams
It's because the motor case is tumbling - it's easier to see and it falls as slow or slower than the rocket, which comes in ballistic - lawn dart.


Thanks, Doug. Lots of food for thought. I'll find one of those post-flight Mosquitoes yet.
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  #20  
Old 03-27-2009, 07:09 PM
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To go back to the Gyroc that started this.... it cato'd yesterday on a flight attempt with an Quest A6-4....one of the main fins ripped off just outboard of the body maybe 30 feet off the launch. It pitched over sharply just before that. The single-finned version was then unstable and just sort of looped around without going far.

I may have to try again but this particular Gyroc is done for, I think. I don't understand it because I recall my first one as being a good flyer.
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