Up Scale Question

The Rocketry Forum

Help Support The Rocketry Forum:

johnnwwa

Well-Known Member
Joined
Jan 18, 2009
Messages
629
Reaction score
0
I want to upscale a known kit from a Bt60 to a Bt70 can any one tell me how to figure fin size . and can this be done using percentages so I can photo copy plans and enlarge ???? maybe I'm going about this the wrong way. help!!! Also need a BNC70L can't find one . either 3.1" or 5.0" not sure yet Sandman you listening?

BAR
John
 

Elapid

Well-Known Member
Joined
May 2, 2009
Messages
1,735
Reaction score
0
all the dimensions by the ratio of the tube sizes.
that works for up OR downscales.

in this case:

2.127/1.637 = 1.3

if you print the templates 130% of original size, you're good to go!
 

Fore Check

Well-Known Member
Joined
Sep 24, 2010
Messages
4,263
Reaction score
7
OOPS!

Hey Elapid, the OD of a BT70 is 2.217", not 2.127". That would make the upscale factor 135%.

As far as your nose cone (John) I'd email or PM Gordon (Sandman) and tell him what you need. In most cases, if you just tell him what the original cone is (a 60L?) and what tube you want it upscaled to fit, he'll hook you up. It sounds like you might not be sure of the dimensions on the original size, so I'd double check that in your case.
 

johnnwwa

Well-Known Member
Joined
Jan 18, 2009
Messages
629
Reaction score
0
Thanks guys
After some thought and searching thats what I came up with 1.36.1 ,math was never my strong point.

BAR
John
 

Elapid

Well-Known Member
Joined
May 2, 2009
Messages
1,735
Reaction score
0
are silly errors like that!
'scuse me!
:eek:
(what are ya? a rocket scientist? hehehhehe ;) )
it only makes for a 4% error on this model, fwiw
:p
 

DynaSoar

Well-Known Member
Joined
Mar 15, 2004
Messages
3,022
Reaction score
0
Originally posted by Elapid
are silly errors like that!
'scuse me!
:eek:
(what are ya? a rocket scientist? hehehhehe ;) )
it only makes for a 4% error on this model, fwiw
:p
That's perfectly good science. In my field, and in most medicine related fields, we use an arbitrary 5% figure of acceptable error as a limit. That means (1) we're at least 95% certain we're right, but (2) up to 5% of our science is incorrect.

I'm glad rockets are engineering rather than science.
 

Latest posts

Top