BT70 Gemini Titan

[gna]

I have 34" of BMS BT70 tubing I picked up on sale at the LHS. I also got fiber dual mount 24mm centering rings for BT70. I'm thinking of building a Gemini Titan scratch build, loosely based on the old Estes kit. So far I've found two nose cones, a Balsa one from BMS and a 3D printed one off Shapeways:

https://www.balsamachining.com/dwgs/cones/bnc70ab.pdf

https://www.shapeways.com/product/M7NRCBQZA/gemini-capsule-nc-for-bt-70-body-tube

Any experience with either one? Haven't a clue how heavy the 3D printed one is.

 

[rharshberger]

Boyce Aerospace Hobbies will sell you a complete kit minus the tubes and they easy to work with, and if they dont show one in BT70 Alex and Sheree are more than willing to scale their offering up or down for a small fee.

 

[gna]

Boyce Aerospace Hobbies will sell you a complete kit minus the tubes and they easy to work with, and if they dont show one in BT70 Alex and Sheree are more than willing to scale their offering up or down for a small fee.

I thought that kit was for BT80? Hmmmm...

 

[rharshberger]

I thought that kit was for BT80? Hmmmm...

Boyce Aerospace did a 4" Mercury Redstone for me as well as a custom Mercury Atlas capsule with missle adapter skirt (for a 5.38" Atlas) and I also have one of their BT80 Mercury Redstone kits, all were vry well done. The custom MA required a small bit of rework on Alex's part as he had to rescale the MR and put the correct window in the MA, results were very nice.

 

[KILTED COWBOY]

They are a great company to trade with.
I have done their Gemini Titan BT80 and in the process of building their Mercury Redstone BT80. Also just finished using their 5 motor cluster fin can for the Estes Saturn V.
High quality kits.
wish they would do a realistic Space shuttle stack

 

[jhall1964]

Hi Fellow Rocketeers!:

I like gna's original concept! I like BOTH of the capsule options. Perhaps you could contact the designer of the 3d printed one and he could give you info on the weight. I was all stoked up to buy the Boyce BT-80 version until I saw all those "ribs" molded into the adapter section behind the capsule. Model companies often confuse those "stripes" with structural ribs on some Gemini kits. But the real adapters were relatively smooth on the outside with stripes painted on the outside of them on some of the missions. On later missions (Gemini 9 for example) there are no "stripes" at all on the modules, but little squares in some locations on the adapter. The rest of the kit is very nice looking, though. I really like the way the clear fins are attached. Just my two cents.

Sincerely,
J.W. Hall
BAR

 

[JPalmer621]

I purchased a set from Boyce BT 70 set last year. Also have a scratch build using the BMS nose cone. I like both. The instrucions for the Estes kit are on line

 

[rharshberger]

Hi Fellow Rocketeers!:

I like gna's original concept! I like BOTH of the capsule options. Perhaps you could contact the designer of the 3d printed one and he could give you info on the weight. I was all stoked up to buy the Boyce BT-80 version until I saw all those "ribs" molded into the adapter section behind the capsule. Model companies often confuse those "stripes" with structural ribs on some Gemini kits. But the real adapters were relatively smooth on the outside with stripes painted on the outside of them on some of the missions. On later missions (Gemini 9 for example) there are no "stripes" at all on the modules, but little squares in some locations on the adapter. The rest of the kit is very nice looking, though. I really like the way the clear fins are attached. Just my two cents.

Sincerely,
J.W. Hall
BAR

Maybe email Alex and let him know there is a "error" with his model and I bet he will thank you, accuracy is important to Boyce Aerospace.

 

[Ez2cDave]

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[Ez2cDave]

Looks like an interesting project.

Dave F.

 

[gna]

I asked the Shapeways seller the weight of the 3D printed nosecone, and he replied:

I dont know. Material data sheet says .45 grams per cu cm for WSF.
But i know 23% less than what is stated on the model for material volume if made of WSF, using that number( i weighed it once long time ago). You should be able to see that on the product. They used to make finding the info easier to see but they are making it harder for not so obvious reasons.$
I should say 23% lighter than calculated to be more specific.​

Boyce sells their Gemini nosecone separately: https://boyceaerospacehobbies.com/collections/rocket-parts/products/gemini-capsule-nose-cone-kit, so that's an option, too.

 

[kuririn]

I asked the Shapeways seller the weight of the 3D printed nosecone, and he replied:

I dont know. Material data sheet says .45 grams per cu cm for WSF.
But i know 23% less than what is stated on the model for material volume if made of WSF, using that number( i weighed it once long time ago). You should be able to see that on the product. They used to make finding the info easier to see but they are making it harder for not so obvious reasons.$
I should say 23% lighter than calculated to be more specific.​

Boyce sells their Gemini nosecone separately: https://boyceaerospacehobbies.com/collections/rocket-parts/products/gemini-capsule-nose-cone-kit, so that's an option, too.

I don't know? What is so hard about getting a printed one and weighing it?
Doesn't sound like great customer service.

 

[KILTED COWBOY]

Shapeways has some nice stuff, but I never could get many questions answered about the products they sell.
Now Boyce on the other hand has great service and returns emails quickly.
For the rivet counters who object to the ribs on the adapter section. It will take some work but they can be sanded smooth.

 

[DWonders]

John Pursley from Accur8 is selling wraps for the BT70 GT on ebay. He also has them for BT-80 sized tubes. I picked up one for the BT-70 and they are amazing. There was also a seller that was providing a 3D printed nose cone/equipment section as well as motor mount and plastic fins. Basically, you just provide the BT-70 tube. Below is the link to the Accur8 wrap.
https://www.ebay.com/itm/Accur8-Gem...963210?hash=item33c296514a:g:jl4AAOSwnbZYIM6u

 

[zog139]

Here is the one I built with BT-70.

 

[John Brohm]

Great job, Jim!

 

[DWonders]

Really nice build Jim. Makes me want to get started on mine.

 

[mikeyd]

I am just finishing my clone up, got the Wraps from Accur8, and a 3d printed truss from Shapeway. However the truss spaces the motor mount further apart than the standard Estes Cluster mount, so you have to modify the centering rings accordingly.

 

[DWonders]

Mike, is this the BT-70 or BT-80 and are you using 24mm motors? Looking really great so far.

 

[mikeyd]

Mike, is this the BT-70 or BT-80 and are you using 24mm motors? Looking really great so far.

BT 70 clone of Estes original