Template: (3)24mm engines in BT 80?

[Darian Rachal]

I am modifying a Big Daddy to a 3 cluster using 24mm engines. I have the motor mount tubes, engine hooks, maybe even rings to fit a BT 80 tube.

Does anyone have a template or know where I can down load one, so I can trace the three engine(triangular) configuration onto some rings.

Just trying to save myself a little trouble. Thanks for any help.

 

[vjp]

Darian - The Big Daddy is a 3.0" tube, not a BT-80 (BT-80 is 2.6").

If you have VoloView or Autodesk DWF Viewer, I can create a quick DWF file for you with TurboCad.

You can get Autodesk DWF Viewer free at https://usa.autodesk.com/adsk/servlet/index?id=2787358&siteID=123112

 

[vjp]

Stepping out for a while - JIC, here's the file (zipped so it will upload).

 

[Darian Rachal]

For some reason I can never open zip files with my computer. When I try to do so, I get a little "Open With" box that asks me which program I want to use to open the file. I have no idea which is the proper one. My OS is 98SE.

I do appreciate the information about the Big Daddy tube size. Not sure where I got the wrong idea.

 

[powderburner]

Darian,

Are you planning to mod the rings that came with the kit? If so, it is a fairly easy thing to overlay the pattern for three new BT50 MMT circles and cut them out. Using the stock Estes white cardboard rings, you would be well advised to reinforce the MMTs with some shear webs running between the three MMTs out to the inside wall of the main BT, and reaching from the fwd CR to the aft. You could also orient each of the three MMTs to be under one of the fins, and cut the fin stub a little short, to just touch those tubes. Don't forget to plug the little space between the three MMTs.

Alternatively, I think maybe one of our TRF vendors offers some lite plywood CRs that are laser cut and ready for three BT50 MMTs. If I am not mistaken, I think Flying Silverado sells these?

 

[Karl]

I run on the same OS as you , you need to get WinZip or WinRAR
-Karl

 

[Darian Rachal]

Powderburner, Thanks for the construction tips. I'll probably follow your suggestions.

Karl, Thanks for the Winzip link. I'll check into it.

 

[Elapid]

if you line up the motor mounts with the fins, the igniters are easier to install.
if you align the MMT so the tubes are between the fins, you can use through the wall fin attatchment.

i'd swap out the cardboard centering rings for some thin aircraft plywood or balsa ply for the extra strength without adding a lot of glue weight.

i would ditch the metal retainer clips and use masking tape to friction fit the motors. this simplifies construction.

if you glue the three tubes together, you can just trace the outline and go for it.

personally, i LOVE the 3x 24mm configuration!
(prolly since i haven't witnessed a 3x38mm launch)

 

[powderburner]

Originally posted by Elapid
if you glue the three tubes together, you can just trace the outline and go for it

Simple, brilliant, effective, and inexpensive. You're going to do this anyway, so why not assemble these parts a bit early?

 

[Darian Rachal]

Thanks to everyone for the ideas. I probably need to get my Initiator, that's still unboxed, done before I start on the BD, though.

 

[jerryb]

Originally posted by Darian Rachal
Thanks to everyone for the ideas. I probably need to get my Initiator, that's still unboxed, done before I start on the BD, though.

darian,

If you cannot open the ones that the other guy loaded...let me know

estes lists the bt-80 at 2.6 od x 2.588 id

the Big Daddy tube I have here measures

3.100 od x 2.920 id

which ring do you actually want the 3 cluster engine in??

I'll can draft those rings in a cadd program and load them in dxf format... MS word will read them as a graphic... just make sure you dont resize them <g>



later
Jerryb

 

[jerryb]

Originally posted by Darian Rachal
Thanks to everyone for the ideas. I probably need to get my Initiator, that's still unboxed, done before I start on the BD, though.

darian, here are rings for both the bt-80 and the big daddy tube in pdf format.

just make sure when you print them, it doesnt rescale them to "fit on the page"

later
jerryb

 

[Darian Rachal]

Thanks Jerryb, the Big Daddy was the one I needed. I guess the FatBoy is BT80. I appreciate your efforts.

 

[jerryb]

Originally posted by Darian Rachal
Thanks Jerryb, the Big Daddy was the one I needed. I guess the FatBoy is BT80. I appreciate your efforts.

no problemo.. if you need anything else let me know.. 18years of cadd drafting shouldnt go to waste huh?? haha

btw.. the holes i put on there are for 1" engine tube.. thats what I have in stock for 24mm motor mounts.. not sure what you use..but the centers are what your wanting if you drill those holes..

holler if you need any more...

later
Jerryb