V2 model help request

Layne -

According to my sources, the BT-55S (the part# listed in the original Estes instructions) was 4.00" long.

"L & K" wrote:

Layne - as a follow-up:

If you size the entire model based on the BT diameter (1.283" for BT-55) you obtain a scale of 1/50.66, making the body length (from tip of the NC to the base of the boattail) 10.335", or 262.5mm.

Subtract the length of the balsa nose and tail cones, and you get a scale body tube length of 78.5mm, quite less than the Estes part originally supplied with the kit (4.00" = 101.6mm).

So if you want to duplicate the Estes kit, go with 4.00", but if you are striving for scale accuracy, 78.5mm is the way to go.

I just happen to have one of the originals :-) The body tube is 4 inches long. As for suggestions, if you go for the scale sized fins, make sure you add sufficient nose weight. Also, you can be a little tight on room for wadding and recovery system. Good luck!

but

Hi, Layne,

I might as well jump in here, too.

The instructions call for BFS-30 fin stock. If you divide that number by 320, you get the thickness in inches - ie, 30/320 = 3/32", so you have picked the right stuff.

BB wrote:

Well, while BB may have an ancient Chinese secret as his source, the rest of us use:

HTH.

Doug

Shhhhhhh! If you give away all of our secrets, how can we continue to manifest ourselves to the masses as gods? ;O)

Pay no attention to the man behind the curtain!

Doug

Well I was right in that I was sure I knew the right people to answer my questions. Thanks very much for the information folks. That was all great input. Doug, BB and Christopher. Knowing now that the actual tube size wasn't even close to scale and that was tight for recovery space I will change my plan to use the scale fins and go with the larger ones. At least I feel better knowing it will fly well.

Layne

Off in the distance, I think I hear the whine of a rotary tool hollowing out the nose cone to make room for the parachute...

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

I always knew the conversions, but never made this obvious leap. Thanks!

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

At long last, a V2 thread!

BB's scale tips are great, but while you're at it, chop some balsa off the fins if you're going for scale. Peter Alway's Scale Bash or Rocket of the World are great resources for templates.

Be prepared to add nose weight though--got to simulate that warhead. I made a BT-50 V2 and it screams on a C6-5. Good luck and have fun!

Louis

I already posted a reply to all those who helped but it didn't show up on my server so I try again.

Well I was right in that I was sure I knew the right people to answer my questions. Thanks very much for the information folks. That was all great input. Doug, BB and Christopher. Knowing now that the actual tube size wasn't even close to scale and that was tight for recovery space I will change my plan to use the scale fins and go with the larger ones. At least I feel better knowing it will fly well.

Layne Rossi Scale would be ok too...

It was a pleasure to be of assistance, Layne. Please let us know how it turns out, and post some photos on alt.binaries.models.rockets if you can!

p.s. anytime you change anything at all from the 'stock' instructions, it's always a good idea to give the model the old "swing" test before the first flight. It sounds like you're sticking to 'stock' though, so this is probably not an issue.

"L & K" wrote:

Hey hey hey! I didn't buy tickets to this place to watch a bunch of "lovey dovey"!

Let's get it on!