Estes (Semroc) BNC-30M length?

[Tau Zero]

So last night, Chas Russell inspired my Estes Hi-G Payloader upscale fit. :rolleyes: ;) :D

The original model uses the BNC-30M, which first showed up in the 1964 Estes catalog, and measures 2.0" long:

http://www.ninfinger.org/~sven/rockets/catalogs/estes64/64est20.html


And today while I'm waiting at my desk for a long-distance phone call from Boise, I spent some time wandering around Carl's site, and came across this particular component:

Balsa Nose Cone BT-30 1.5" Ogive (BNC-30M)

http://www.semroc.com/Store/Scripts/prodView.asp?idproduct=599


*Oops.* I hate to be the "Nose Cone Police," but we've got another one that needs some attention... apparently. :o


FYI, and *THANKS!* as always! "All y'all" make rocketry fun! (Again. :cool: )


Cheers,

[Chas Russell]

Okay, now we have a mystery! Glad we can entertain you Jay!

I noticed that BMS does not offer at 30M cone. I was hoping to collaborate one length or the other. If I can dig out the photo of the model I built, I may be able get a rough length of the cone. Assuming that I was anal enough back in the late '60s to use the parts called for in the plan.

Anyone...Anyone...? Vern?

FWIW, we konw the catalogs were not always accurate. Seems the cone was longer than 1.5".

Maybe Carl needs to make a BNC-30M(*) cone...

Chas

[Carl@Semroc]

It's not just the BNC-30M! It is also the BNC-30C. These were based on drawings and descriptions in plans, catalogs, etc.

BNC-30C

The old Estes BNC-2A was the precursor of the BNC-30C. It has an exposed length of .75". It was used on Gleda's modified Space Plane. The Lil' Augie had a mispring and stated the BNC-30C was a replacement for the BNC-3A. It should have said BNC-2A. Our "bad" BNC-30C is based on the Lil' Augie. Now one will be spherical and .75" exposed.

BNC-30M

Estes released the BNC-30M in Vol3 Num3 along with the BNC-30N for the Sky Hook. I still don't know why they released the 30M. The Hi-G and Sly Bolt are the only places I can find that it is used. The length is listed as 2.00" in the New Products section and the BNC-20N is listed as 3.25". The exposed length of the BNC-30N is 2.75" and the assumed length of the exposed section of the BNC-30M is 1.5". The Sly Bolt shows the exposed section to be dimensioned as 1.5". The HI-G calculates to 2.0" exposed. Even the photo and drawings show it as closer to 2.0" exposed.

Estes for a long time showed dimension 4 as the overall length and confused themselves at times. One of the Sky Hook plans shows the OVERALL length of the nose cone as 2.75". That scared us when we had just finished kitting the first hundred Sky Hooks! I did not want to be the one to tell Sheryl we had to open all them and put shorter nose cones in them. I found an old Sky Hook in the archives and the balsa nose cone in it was 2.75" EXPOSED. Between Catalog 651 and 691 they changed Dimension 4 to Dimension 1 and used it as the overall length. IN 701 they changed it to the exposed length. The tables did not change. Up until they stopped making BNC-30M's, the exposed length was still 1.5". All the pictures and drawings show it as at least 2.0".

I am changing ours to match the drawings. 2.0" exposed. I am also fixing the BNC-30C which has always been just wrong.


And Chas, (back on topic), I never liked the bond paper cover for engine hooks, so I never built the Hi-G!