3X Goblin

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matt_taylor

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hi guys
im going to build a 3X upscale Estes Goblin using some 4" tube i have, but i have been looking at the plans on Jimz web site
and i dont realy get all the diffrent BT tubes can some one help me? also i have read around on the forum about making nose cones and i wanna try how you i make one with a Hand drill , foam cutter etc......??? were is a good place to buy decals?
its gonna be a 29mm and 6 24mm cluster



thanx
matt
 
just thinking my local hobby shop sell 40X40mm balsa blocks mabye if i glued them together or glue 4 20mm blocks?


thanx
matt
 
matt,

I think I can help here. The part number of the tube is a BT-55 IJ. Refer to this chart here:

https://www.ninfinger.org/~sven/rockets/body_tubes.html

Now, as you can see on the chart a BT-55IJ is a 9" long BT-55 tube. Now a BT-55 is 1.325" in diameter and your tube is 4" in diameter divide 4" / 1.325" and get 3.0188----times 9" equal a 27.17" long tube or....

690.113mm long.

easy, HUH!

sandman
 
hi
Thanx Sandman for that , thats one question done now only a few more:)


thanx
matt
 
hi
can some one give me the dimetions on the BNC 55 AD
also were is a good program for printing out nose cone templates
i started on making the CR and bulkheads today and im going to fiberglass the Body tube tonight
im getting a digital camera soon so i will be able to post pics


thanx
matt
 
Matt:

I'm not sure if this will help you, attached is a 0ne page scale plan for the goblin Micro-Maxx size:)
I'll attach in the next post, a pic of my 3X upscale 5 D12 cluster based on a BT-101 (3.896") tube. you may be able to scale the tube length from the pic.
hope this helps
 
hi
thanks for all the help guys , i fiberglassed the body tube today
looking at sandman's pic the nose cone is 5.5" long is that right?
also were is a good place to buy decals ?

thanx
matt
 
Micromister, cool pic of the upscale, i want to have a 29mm in the center and have 6 24mm's so having a high thurst motor like the H220T if some of the D's dont lite it should have any troubles
im thinking of use a Magnetic Apogee Detector in the nose cone for chute deploymet , as then i can use my Ex sugar motors


Matt
 
i was just working it out i would have a 16.6" nose cone for a 3X upscale? also were is a good place to print a template to make the cone??



thanx
matt
 
matt,

Try this "low tech" approach.

Print the shape of the nose cone from the Balsa Machining Services site.

Cut out the patern, maybe transfer it onto a card stock or something firmer that paper.

Pin or tape a piece of card stock that the final size of the pattern will be on, onto a wall.

Place the body tube in front of the pattern then hold the cutout pattern up between the wall and a light.

Move the pattern back and forth until the size matches.

Get a helper to trace the matched outline on the card then cut it out.

Pretty "low tech" , huh?.

My brother used that same technique to paint the silloette of a Ford model T on his garage door but he used a slide projector. Neighbors thought he was putting on a show.

sandman
 
matt,

Move the small cutout pattern from the web site of the BNC-55AO back and in front of a light until it's shadow matches the size of the big body tube.

sandman
 
matt,

I think I can help here. The part number of the tube is a BT-55 IJ. Refer to this chart here:

https://www.ninfinger.org/~sven/rockets/body_tubes.html

Now, as you can see on the chart a BT-55IJ is a 9" long BT-55 tube. Now a BT-55 is 1.325" in diameter and your tube is 4" in diameter divide 4" / 1.325" and get 3.0188----times 9" equal a 27.17" long tube or....

690.113mm long.

easy, HUH!

sandman
How does the diameter have to do with the length ?
 
This might be the oldest thread necromancy yet at almost 16 years since it died to ressurection. [emoji3]
 
Since I brought this thread back from the dead. What is the formula for scaling fins?

It is pretty simple - for a 3x upscale, multiply all dimensions by three, for a 4x upscale, multiply by four, et cetera.
 
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