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Missile Command RTF : Army

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PWALPOCO

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Does anyone here have any experience with the Estes "Missile Command RTF : Army" rocket ?

My freind Woody and I both have the Army / Navy Combo of this set and the pair of us flew both our ARMY versions for the first time today. Woody flew his NAVY on a previos occasion but neither of mine had flown before. So basically neither of us have had experience of the ARMY unit.

We flew the ARMY units 3 times, Woodys twice , mine once and found that on my flight and on one of Woodys the rocket gave some alarming flight characteristics !!

On Woodys 1st flight the rocket must of only got 30ft max when it went into a horizontal corkscrew flight then returned to earth about 5 meters from me (with the launch controller). The rocket motor burned out then "popped" with the ejection while laying down on its side. No one was hurt, but you do kinda think of the "what ifs".

The second flight , again with Woodys ARMY flew a little more regular but still flew in a curved path.

Hoping that the first flight was just "unfortunate" we tested my ARMY unit out. We placed it on the pad and launched. Again we ended up with a horizontal corkscrew flight , though at a higher altitude , maybe 50-100ft. The rocket then nosedived to the ground. The Rocket was upside down , buried up to the nosecone and smoking, and a few seconds later , POP , the charge went off. The BT was ejected from the buried cone and the chute "deployed" nicely ...... :rolleyes:


The consequences for these incidents could have been quite severe if we hadnt gone through the ritual of finding a big open space and ensuring the area was clear of people. We did have spectators on a very distant dune but they were well away from any danger. While Woody and I chose our spot with care ( and are fortunate to have such a good place to fly from) others may not be so lucky.

Can someone shed any light on these incidents as we launched a few different rocket types and it surely must be more than coincidence that our groups first real nasty incidents involved two rockets of exactly the same type.

Does the ARMY unit have a bed rep in the rocketry scene or were Woody and I doing the same things wrong ? :(

Paul
 

teflonrocketry1

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I bet you flew the rocket on a C6- motor and the wind was blowing at about 10 mph when it went unstable! The Estes Army model and the Navy are known to be only marginally stable on a C motor. My simulation of this model, Estes #1818, ( http://www.rocketreviews.com/cgi-bin/search/searchall.cgi?Estes+Army#RS ) shows flights to be unstable on a C motor in winds greater than 5mph! This is one of the most accurate simulations I ever did with RockSim Version 4. Put a 1/2 ounce of modelling clay inside the nosecone and both models will give much better flights on A, B and C motors.

Also note that the Army Rocket is identical to the Banshee and the Navy is identical to the MK109 Stingray.

Bruce S. Levison, NAR #69055
 

Fore Check

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(see Bruce's notes above)

I had the same experience with my Army rocket. Never did have a problem with the Navy rocket, tho. Same launch conditions, both on C's.
 

teflonrocketry1

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The Army/Banshee design is definately the worst of the two. Both the cardboard cutout method and the Barrowman method say this design is unstable on an A8-3 motor (-1.17 and 0.28 caliber stability margins respectively. RockSim indicates a stability margin of 0.91 which I believe to be correct based the flight logs at EMRR:

http://www.rocketreviews.com/cgi-bin/flightlog/flightlog.cgi?listrocket&&Estes%US%Army%(RTF)

http://www.rocketreviews.com/cgi-bin/flightlog/flightlog.cgi?listrocket&&Estes%Industries%-%Banshee

Bruce S. Levison, NAR #69055
 

shrox

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Nose weight excises many rocket demons...on these two rockets in particular. I like the MK109 Stingray design, it has a nice look.

shrox
 

PWALPOCO

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Yes we flew the Navy on the same day and with C-6's and the Army 3 times with C6's also.

The Navy flights were perfect and the Army flights were as described. Wind Speed was measured at 0-2mph and the video we took shows the safety cap ribbon on the adjacent launch rod to be hanging straight down.

We had considered stability to be the issue but were just surprised that in near pefect conditions the flights could go so hiddeously wrong !

Ive grounded mine but may try again after adding some weight and will look to fly on a lower powered engine.

Thanks everyone for their help.

Paul
 
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