Tri-Star: build thread in coming!

[JDcluster]

I thought someone would have already started a thread on one??

Here goes (along with the other 3 projects I'm working on)!
I still have my 7 motor cluster rocket thread that hasn't been forgotten.
I'm bringing all projects to the same level so, I can get all the fiberglass lay-ups done at once.

This one came up on Black Friday sale from: County line Hobbies and I knew I couldn't pass this one up;
Especially being a limited run!
https://www.countylinehobbies.com/

Eventually I intend on fiber glassing the main 4" (24" long) section and maybe the upper 3" (10" long).

The plan is to fly it at LDRS and maybe a MDRA launch(s) if weather and time permits.
I hope to fly it on 3 EX motors of mine. The grains have already been cast ( just need to be cored).
First flight I plan on is: 3 x AT G 138's as a test flight.

First, the unboxing / bagging pics:





The first thing I did was profile the fins for a nicer look and better aerodynamics







The next task was to peel off all of the glassine layer from the three 38 mm motor tubes ( 27" long)
for bonding using wood glue!


I've attached an updated Rock Sim of this rocket.


Next segment will be:
Gluing the 38 MM's together, motor retention, and prepping to attach the fins.


JD

 

[bob jablonski]

Watching on how you will do the motor retention. In my King Viper I put a threaded rod about 3" long in the channel between the motor tubes and one nut and washer holds all 3 motors in.
Mr. Bob
Countyline Hobbies

 

[JDcluster]

One thing I was disappointed with was: the only 2 CR's were only 1/8" thick.

The motor retention had me twisting and turning in my sleep.
I think simpler is better! I'm not a big fan of having a metal rod sticking out the back either.


JD

 

[Pyropetepete]

Defo agree the rings need too be thicker. Both this product and other clusters using the same concept

 

[cavecentral]

I'm not a big fan of having a metal rod sticking out the back either.

Try potting a 1/4- 20 All thread connecting nut in the center, then use a bolt / washer. Same concept, but better during display mode.

 

[JDcluster]

I already thought and tried that.... The threaded couplers are too big.
Found a better way; tune in tomorrow for the next installment.

JD

Try potting a 1/4- 20 All thread connecting nut in the center, then use a bolt / washer. Same concept, but better during display mode.

 

[JDcluster]

Part 2.

I started with gluing two of the 38 motor tubes together with Titebond 2 wood glue ( yes wood glue!)


I drew 2 lines on the tubes to indicate the glue joint, so I know where it needs to go.



I added some 1/4 oak dowels for reinforcement in the seams between the fins and the CR's.
That was after the initial glue joint started to cure ( I didn't want the tubes misaligned).


The other 2 dowels will have to wait till the third motor tube has been glued on....

Now I can tackle motor retention.

I tried a few thing in my arsenal of hardware on hand.
That lead me to use:
10-32 brass inserts from Du-Bro found in many hobby shops.
I had just ordered some machine screws from Mc Master so, it was a perfect match!

Also checking fin fitment into the seam next to it is the threaded insert with machine screw.



A pic of me gluing the insert in place with Proline Epoxy and about to attach the third motor tube


Last pic for this segment:



JD

 

[JDcluster]

Another tip trick here:

The Loc packaging makes a great workspace drop sheet.


JD

 

[WillMarchant]

Is there enough room for aft closures (i.e. reloadable hardware) with the tubes glued directly to one another?

 

[JDcluster]

Looks like it....





JD

 

[WillMarchant]

Looks like it....

View attachment 249941



JD

Cool, thanks!

 

[JDcluster]

Third installment:

It went together quicker than my normal builds even with the improvised upgrades.

Anyway, you can see here that I've attached the first of the 3 fins.
I used some more 1/4 oak dowels to help position the fin.
I'm using just wood glue to bond them.







Just about ready to attach the third and final fin



After attaching the third fin I let it cure for a few hours
then went for the final step on the fin can section; the Centering rings.
As stated earlier; these are way too thin (for my liking) 1/8" thick.
I would have liked them to be at least 3/16" or better with 1/4 plywood.

I had to beef them up some how so, I added some more dowels.
This time I switched to 7/8 poplar dowels as HD only has poplar in 7/8" size.
I was going to go with 1" but, they stick out a little too much.

Here is a pic the 2 CR's are sandwiching the 3 dowels that rest in the valleys of the 38 MM.



My next steps will (probably take longer before the next update) include: fillets and glassing tubes.

JD

 

[bob jablonski]

If anyone is interested I still have 2 more Tristar kits in stock. Sorry they are not at Black Friday prices. I will get a few more made later for a Tristar drag race at LDRS.
Now back to the build.....
Mr. Bob
Countyline Hobbies
Grovertown, IN.
574-540-1123
[email protected]
www.countylinehobbies.com

 

[JDcluster]

Next installment...

Fiber glassing.
I don't like it all that much ( it's messy) but, it's necessary for added strength and durability.
I'm using 2 layers for the fins; 6 oz plain weave and a 3oz e-glass that is much finer and gives a better finished product.
The fins will be done in 3 steps or three separate applications.



A different angle.


JD

 

[JDcluster]

One more pic after I trimmed off the excess cloth, once it was past the green stage:



JD

 

[blackjack2564]

JD this build has got me thinking....it's time to dust off the ole Ultimate Endeavor cluster rocket and start flying it again!

I love clusters! Really nice way to break the normal flying and have some excitement.
Looking forward to seeing your project fly!

 

[codysmith]

JD this build has got me thinking....it's time to dust off the ole Ultimate Endeavor cluster rocket and start flying it again!

I love clusters! Really nice way to break the normal flying and have some excitement.
Looking forward to seeing your project fly!

Jim, when it comes to you is there such thing as "normal" flying???

 

[JDcluster]

I thought I had 6oz... it turns out that it's actually 4.5oz.
No big deal.
I've been putting this off for a while now and can't remember the last time I did any fiber glass work.

I found a 4" booster from a PML eclipse that needed glassing so I did that as well.
It's been sitting for so long that somewhere along the way; the phenolic took a hit, now there's a hole between 2 of the fins.


JD

 

[JDcluster]

The last leg of fiber glassing the fins.


I just added another mod to this build.


I sanded down one of those measly CR's so that, I could slide a coupler over the top of it.....
Hope it helps with the alignment with the main tube.


JD

 

[JDcluster]

A small update as other projects are being worked on as well.

I decided to fg the entire booster section.
It will add more weight but help with the surface texture.



I've also started fiber glassing the main 4" tube.

It came out a little rougher than expected but, nothing some sand paper can't solve.

JD

 

[Bat-mite]

op:

 

[JDcluster]

A little more work on the tubes.
I have 2 tubes one of which will be used as the main 4" booster section.

I'm not sure which one yet.....
The stock tube is 24" and the other tube is 20".
Both are now glassed.

This one here is the 20" long tube.

It came out better than the first.

The 24" tube weighs 373 grams with the 2 layers of glass before finish sanding and or primer / paint.


I just weighed the booster, and it weighs 900 grams. It too still needs finishing; sanding , primer, paint.

JD

 

[JDcluster]

Update:
It's been over 2 months since the last update so...

Altimeter bay setup has been finalized.
Here are some of the parts before I started putting it together:



JD

 

[JDcluster]

Now I glue the caps on, one on each end essentially sandwiching the transition.


That is a 38 mm PML tube to house an altimeter.




JD

 

[cls]

Tristar is one of my favorites of my fleet. It is agree at design, very handsome. Built mine completely stock, the parts are sturdy enough. I use masking tape and friction fit the motors, simpler is better.

I stopped flying it because no clubs launch equipment could reliably light three first fires. I ought to dig it out and fly with cti motors with the ematch igniter.

 

[SCP]

I'm just finishing up a custom retainer for a customer, not a Tri Star exactly but similar enough , I could see if the customer would mind if I showed it here. It's pretty cool....

Watching on how you will do the motor retention. In my King Viper I put a threaded rod about 3" long in the channel between the motor tubes and one nut and washer holds all 3 motors in.
Mr. Bob
Countyline Hobbies

 

[bob jablonski]

Us old dogs are always open to new ways of doing things.

 

[bob jablonski]

Us old dogs are always open to new ways of doing things. By the way like your website. Rockets and dirt bikes (just picked up a 1978 RM 125)

 

[SCP]

The RM125C is my all time favorite bike! haha!

 

[SCP]

Found my "permission slip" from this customer to show this custom solution to a cluster retainer.....in answer to Bob's prior comment...........

Different in scale of course, but minus the 98mm central, the cloverleaf retainer is pretty adaptable to other layouts.