19 replies to this topic

[dr thrust]

Does anyway know exacty how big the nozzle to tube ID ratio is for the estes rockets just wondering? With my end burners i found that a 4mm nozzle on a 19mm (3/4 inch ID) tube with straight black powder give a decent thrust. Well it settled at about 500g thrust as i said before dont know how good this is for an end burner but was told is wasnt that good. see this link for vid of the test i done

What about the thrust of these end burning estes rockets anyone know what it is??

thats a great vid i must of watched it twenty times! mostly on wet sundays! i guess the best way to find out would be to buy some. "ching ching" they seem to make alot of different powered motors with the same id. have you done any test flights with your end burners? whats in your comp ali?

[Pyromaster2003]

Had a look around on the forum and someone said the standard estes comp is 71.79:13.45:13.81 + 0.95 dextrin so im off to try this now. Iv tested both rockets in the video and they both fly very fast - the 3/4 inch one must reach 500-600 feet in a few seconds im making a couple now so il fire em tonight when its dark and post vid.

btw the comp is straight meal out of the mill and cheers for comment..

Edited by Pyromaster2003, 02 July 2007 - 06:41 PM.

[Pyromaster2003]

Well done some tests tonight and the estes comp is pathetic compared to the standard BP ratio. Got 500g thrust with the estes comp in a 3/4 inch ID tube and got over a 1000g thrust with standard BP.

Didnt make the rocket flight test i said i would coz tonight has been a joke on my expense really. test fired on my scales 4 3/4 inch rockets, 1 turned a thick walled commercial tube to paper shreads and the other 3 for some BA$TARD reason burnt through near the nozzle..i have made many rockets with exactly the same specs and comp as these but never had this problem.

Video of one of the rockets is here-

[dr thrust]

hi pyromaster are you ramming or pressing your comp? i want to build a press,what tonnage are we talking,i asked the question on the "press"forum but nobody answered

[Pyromaster2003]

For end burning rockets theres no need to use a press i just ram the milled black powder. Havnt got a press yet neither planning on making a wooden one in a couple of weeks if your making one a 10tonne jack is easily enough for anything you need to press. Mine is 20 tonne but theres no need for that much..