PDA

View Full Version : Scale math

Scotty Dog
27th September 2010, 05:08 PM
Did I get this right? I want to up scale a rocket. The rocket I have is a BT 50 O.D.=.976 I want to upscale to a BT70 O.D.=2.217.So I took the 2.217 divided by .976 came out with 2.271 So,if the rocket I have has a BT 10" long the upscale BT70 would be 10x2.271=22.71 " Also ,do I multiply the fin dimensions by 2.271????? Thanks

TheAviator
27th September 2010, 05:12 PM
You've got it! I like to round things to the nearest 1/8" or 1/16" just to make everything nice. Obviously you don't want to do this when entering a scale competition, but it works for up/down scales of other model rockets.

Scotty Dog
27th September 2010, 05:21 PM
You've got it! I like to round things to the nearest 1/8" or 1/16" just to make everything nice. Obviously you don't want to do this when entering a scale competition, but it works for up/down scales of other model rockets.Thanks ,Im going to upscale the Fliskits Stingray.Working on getting parts for my "winter builds".I bought the Ray and built it this month for the Fliskits Party at Cmass. Now that I have built it and flown it I have come to REALLY like this rocket and the way it looks.So I want to go BIGGER BABY!!

TheAviator
27th September 2010, 06:46 PM
I know what you mean. My L1 was on an upscale Estes Guardian. 3.1"/1.325" = 2.34x scale factor. Also 2.34x cool factor.

Scotty Dog
27th September 2010, 07:46 PM
I know what you mean. My L1 was on an upscale Estes Guardian. 3.1"/1.325" = 2.34x scale factor. Also 2.34x cool factor.How could I forget the COOL Factor.Yours looks COOL!

KennB
27th September 2010, 08:20 PM
I know what you mean. My L1 was on an upscale Estes Guardian. 3.1"/1.325" = 2.34x scale factor. Also 2.34x cool factor.

Brian, the rocket's dimensions go up on a linear scale. The coolness goes up by the square or cube of the scale factor. Nice rocket.

Fore Check
30th September 2010, 11:59 PM
Brian, the rocket's dimensions go up on a linear scale. The coolness goes up by the square or cube of the scale factor. Nice rocket.

LOL :cool:

I will add that it helps to have a chart of available tube sizes handy - particularly if you are scaling (up!) something with multiple sizes of tubes (motor mount doesn't really count.) Sometimes your first choice of a scale factor can turn out to be impractical - or less congruent in the chosen scale - due to the available tubes, and a slight adjustment to the scale factor to a different airframe size can line it up real nice. :2:

Your math is right on the money. :)

Scotty Dog
1st October 2010, 12:56 AM
LOL :cool:

I will add that it helps to have a chart of available tube sizes handy - particularly if you are scaling (up!) something with multiple sizes of tubes (motor mount doesn't really count.) Sometimes your first choice of a scale factor can turn out to be impractical - or less congruent in the chosen scale - due to the available tubes, and a slight adjustment to the scale factor to a different airframe size can line it up real nice. :2:

Your math is right on the money. :)
The tube size in this case is what set the scale factor.As I mentioned,I want to build a bigger Stingray. I have tons (not really, but a bunch) of BT70s. So an upscale to a BT70 is what Im shooting for.I get what your saying.If one was to do a scale of a whole number;1,2,3,4,ect I see going your route. Now a "Q" about you-HOCKEY??????

Fore Check
1st October 2010, 10:06 AM

:o

Go BLUES!!!!!!

:confused2:

Scotty Dog
1st October 2010, 02:18 PM
:o

Go BLUES!!!!!!