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View Full Version : Big Daddy on steroids


Tweener
05-08-2006, 02:50 PM
Well, I started my rocket launching season this year - finally. Yesterday I brought out my Big Daddy to the RC flying site because I knew there had to be a way to impress on these guys that rockets can really be "way cool". They've never really shown much interest in my 18mm or 24mm D launches, so this time I rolled out the big guns with an E15-7. Since the BD was built with D in mind (3/16" lug), I've had a bit of a problem with rod whip on my two previous E launches. This time, I angled the rod and pushed gently on the tip until more than moderate pressure would be needed to point the tip past straight up, then situated the rocket on the short angle side. The result was a perfectly straight liftoff to at least 900' that finally provoked a few "ooohs" and "aaahs" from my RC gang. :D

BTW, if anyone trys this engine - either reef the chute or add a lot of extra shock cord. I did the latter after the first launch last year because two of the shroud lines broke loose. No problems since.

John Brohm
05-08-2006, 07:23 PM
...so this time I rolled out the big guns with an E15-7.... The result was a perfectly straight liftoff to at least 900' that finally provoked a few "ooohs" and "aaahs" from my RC gang. :D



Hey Lance;

Pretty awesome, but try it next time on the 24 mm F21-6; you'll be glad you did. It's got to be one of my favorite engines.

Tweener
05-08-2006, 09:14 PM
Well, unfortunately this is the old Big Daddy with the 2.75" length motor mount. The E15 and E30 are the only two that will fit her. Craig ran a rock sim last year for me that predicted that the E30-7 would have the lower speed at ejection (just past apogee), but I really had a desire to see a launch with a thrust phase over 2.5 seconds, so went with the 15's. In all I've burned 3 since last year and still have one left. I'm building a Thunder Roc clone that I'm considering breaking in with that. :D