Baby Bertha vs. Ranger K-6 nose cone?

[SolarYellow]

Thinking about doing a Ranger K-6 -ish build with an extra Baby Bertha nose cone and fins.

I know the Ranger's nose cone is longer. I believe it's roughly along the lines of the Baby Bertha cone being like the BMS BNC-60MS

https://www.balsamachining.com/dwgs/cones/BNC60MS.gif
and the Ranger cone being like the BMS BNC-60L.

https://www.balsamachining.com/dwgs/cones/BNC60L.gif
Could I hack my spare PNC-60 whatever (Baby Bertha) cone into the 60L by replacing the shoulder with a chunk of coupler and sleeving it with a chunk of BT of the appropriate length?

Basically, is the last part of the BNC-60L nose cone straight, or does it taper starting right at the base. If so, is it enough that straight with a well-filled seam wouldn't look right?

 

[BEC]

Well, as has come up in several Big Bertha threads here and on YORF, it was noted that the Estes nose cone machines wore and as they did the nose cone shape changed. The more recent BNC-60Ls were essentially the same shape as the blow-molded Big/Baby Bertha nose cone of today — only a little longer. There was a two-piece injection-molded plastic PNC-60L before the current one that was closer….but that’s not what you asked.

This nose cone https://www.erockets.biz/semroc-balsa-nose-cone-bt-60-3-1-bezier-sem-bnc-60lv/ was Carl McLawhorn’s attempt to match the earliest BNC-60L, as seen on Vern Estes’ original Big Bertha. Granted, that’s a pricey piece of balsa (as is all balsa these days) but that’s the easiest way to get very close to the “correct” shape.

 

[SolarYellow]

Thanks for the pointer. I've actually read a ton of Ranger threads already and didn't get to that info.

It clearly is a little finer toward the tip than the Baby nose cone, and I'd have to say a little better looking. But it also appears that the base is at least really close to straight for a good distance. At least enough that my question of whether it would be reasonable to just add some BT to get to the right length appears to be, "Yes."

That is a pricy piece of Balsa. It doesn't at all fit in the window of "random spare parts taking up space in my parts box that would be fun to build something with."

 

[BEC]

It doesn't at all fit in the window of "random spare parts taking up space in my parts box that would be fun to build something with."

 

[bjphoenix]

I think it's close enough to get the same effect. I have a Ranger nose cone in my stuff from about 1967 and a Baby Bertha in my fleet so I could provide measurements.
Here is the Ranger from 1967: