A blog comment made mention of the Big Bertha nose cone. The shape and length have changed over the years. The old balsa BNC-60L nose cone had 3 1/8"exposed above the body tube edge. It was longer and not so blunt as the current plastic PNC-60L or part #71020.Here's the parts layout from some old Big Bertha instructions. Compare the "A" part balsa nose cone to the current Big Bertha and Baby Bertha nose cones.
To see the older instructions go to oldrocketplans.com or CLICK HERE:
Here's a better profile example of the original nose cone shape, a rounded ogive.
You can get it from erockets.biz: CLICK HERE
This original Big Bertha was produced before engine hooks were used in larger diameter models. The earliest engine "holder" hook I can find was in the 1966 Estes catalog.
I first saw this simple outside the engine mount tape retention method on an Apogee video. I don't remember ever using this when I was in my teens, my rocketry experience started in 1969. We certainly used a lot of masking tape "friction fits" until more engine hooks were introduced into kits. Until today, I didn't know how far back this tape retention method went!
I sure don’t remember suggestions like this, to wrap tape around the motor tube. That was pretty common, though, in the 90s for HPR. I always thought it was “inelegant”, and used T-nuts or threaded inserts in the aft centering ring, and fashioned my own metal hooks. I have used this tape wrap method on one model rocket — the Fliskits Dueces Wild. I used metal tape on the protruding tube ends (tape like the HVAC guys us to seal ductwork on furnaces). It’s great because it won’t peel off, like paint might, when the masking tape is removed.
ReplyDeleteI do like that shape better than the current Bertha cone. Need to make the drive to Dayton, buy some stuff and hang out for a build-night - fun times with the WSR club and eRockets folks!
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