CJ's "HOW TO BUILD A DARKSTAR 3 OR ANY GLASS KIT BUILD" STARTS

Finally....

Remove fins, insert Motor mount assembly into fincan & check for fit.
Place all fins in corresponding slots.


TIP:
...............................
While doing this I draw a line on all fins where they meet airframe.
Your fins should have a nice snug fit, to the point that some may need a light tap or 2 ,making sure they bottom out on motor mount.

When it comes time to tack the fins, its' readily visible if fin it seated correctly. Just a bit off and the glue will be a leaky mess. See the crooked line on rear fin, it is tight, but that's an illusion, it's not down tight to tube. A whack or 2 & it's fixed.
So this little line acts like a visable "safety" check, saving time & fixing stuff!

..................................................................

After all is fitted,[if not make your adjustments that why it's just tacked & dry fitted] I assemble the bird for the first time and admire!

Oh yeah , make sure bevel is to rear on lower fin.[yep some are out there backwards]

Ok so it all fits great.

Remove the fins & MM assembly.
Stuff Kevlar into MM, keeping it out of glues way.

Now we glue the CR's and recovery harness permanently.
No glue on sides of CR where fins touch!


Starting from Top. Fillet Nose side of Top centering ring.

Middle 2 rings get fillets on the short/inside only.

Bottom/back CR gets a fillet on aft side.
............................................................

Tape, so fin attach area gets no glue on it.


Now I mix some thickened 15minute epoxy for the Kevlar.

Lift KEVLAR and spread underneath. Push Kevlar into epoxy.
Coat/encapsulate entire recovery cord.... both of them. LOL:grin:

Remove tape after glue sets a bit.[but before cure or you'll never get it off.]

Alrighty then... we have now officially finished with the fincan & can start assembly!

I should probably let some catch up to me, I'll go have a smoke.LOL

Do we have many of you building these things?
Or are you still waiting for them to arrive?

Or am I just wasting my time? [ just seeing who's still awake]

Mine should be here Monday
Thanks for thread and all the tips.

Still following and picking up tips, waiting till Xmas when I'm allowed to open mine this is all just a huge tease with the closed box sitting in my basement!

And by the way....

don't give me that mamby, pamby BS about..."I only got 3 CR's". Happened to me last year, with the Vindicator special, so I just made one out of tape. Did not want to wait or order one. Knew better this year & ordered and extra.:cyclops:

So if ya want to inject the internals, just follow same as above and substitute a masking tape ring...it only needs to be 3/8 to 1/2 in high just enough to hold the glue from going out the back.It does NOT have to be full height like the rest of them. Once the epoxy sets, the fin don't know the difference.

"It IS rocket science and we must treat it as such from time to time & wing it on our own".:wink:

Where would modern civilization be, with out tape & batteries? I shudder the thought!:y:

Hey Jim - I was away from the computer this weekend, and have a question about the Aeropak. If the fit (location fore-aft) is critical for proper engagement of the tailcone ring to the body tube, why would you spend additional time to measure and fit the tailcone before the fincan is assembled into the booster? Wouldn't it save time - and potential errors/shifts - to wait until the rear assembly is complete. Then bond the retainer body to the motor tube with the tailcone/retainer in place and tight.

Even if you are trying to maximize the amount of engagement between the motor tube and the retainer body, you could mark the mount. That would allow you to file the motor tube in the event of a small mismatch the wrong direction.

I ask because I'm the guy who will carefully measure and match fit everything, only to find in the final assembly that I'm a couple of hundredths off - always in the wrong direction. Bonding the retainer body so early just seems like a recipe for disaster in my shop.

edit: I still am awaiting my order...though now I wonder if I should cancel the 75mm casing set since it's not going to fit in this and I don't have any other use forit.

blackjack2564 said:

And by the way....

don't give me that mamby, pamby BS about..."I only got 3 CR's".

Click to expand...

But, Jim, I only got 3 centering rings!


:tongue:


:rofl:

JordanT said:

1.Hey Jim -
Wouldn't it save time - and potential errors/shifts - to wait until the rear assembly is complete. Then bond the retainer body to the motor tube with the tailcone/retainer in place and tight.

Even if you are trying to maximize the amount of engagement between the motor tube and the retainer body, you could mark the mount. That would allow you to file the motor tube in the event of a small mismatch the wrong direction.

2. Bonding the retainer body so early just seems like a recipe for disaster in my shop.

3. edit: I still am awaiting my order...though now I wonder if I should cancel the 75mm casing set since it's not going to fit in this and I don't have any other use forit.

Click to expand...

1.Honestly... because I didn't think of it.[Your way] It was my first tailcone & I was determined to get it on.LOL Yeah a bit of sanding could correct any problems - after the fact. Yes that would work. Pre-mark and install last. You would have to be sure the was enough excess tube sticking out for sure.....If your short....your scr#$ed!

2. Not at all. I don't think so. It was really quite simple...it worked..your just tacking stuff on...checking the fit...once it's a go, then it gets glue. Just takes more time to explain what I did, than actually doing it.

3. I wouldn't do that! I got the set too...what a deal.
You can always put the fins together and trace a template for the Cowboy fins, before you build this. [1sq ft. of 1/8 in G-10 will do the trick ,20 bucks] and a section of 3in.tube for a fincan. Use the top half on both rockets...that's what I'm doing now. My 3in Wildman & SC share the payload/NC.

Pantherjon said:

But, Jim, I only got 3 centering rings!


:tongue:


:rofl:

Click to expand...

The Teletubbies stole yours.....took it to MAMBY PAMBY land! :smile:

Green Jello said:

Is the kit supposed to come with 3 or 4 CRs? I'm at work at the moment and can't remember how many I got.

Click to expand...

It comes with 3.

You started yet?

blackjack2564 said:

It comes with 3.

You started yet?

Click to expand...

Not really. I'm just "soaking in" your thread and gathering the needed materials. I did some light sanding and built the bulkhead plates. I'm doing your nosecone mod, so I acquired the threaded rod and ordered this today:

https://www.fastenal.com/web/products/detail.ex?sku=0501514

I also did some pre-planning on the electronics sled and bought some basswood and threaded rod for it.

blackjack2564 said:

Do we have many of you building these things?
Or are you still waiting for them to arrive?

Or am I just wasting my time? [ just seeing who's still awake]

Click to expand...

Considering the number of views this thread has, I don't think you are wasting time. Probably a hundred of those views have been mine. My blackstar is scheduled for delivery Wednesday. I was fortunate to get a call from Tim as he was packing my stuff up and mentioned that I planned to do your "injected" method, so he threw in extra CR's for all three of my rockets. I also picked up a quart of West systems epoxy and chopped carbon fiber. I will be picking up the hardware to make my N/C like yours too.
I just want you to know how much I appreciate this build thread Jim. Having only built one fiberglass rocket (the Jart), this is exactly what I need to get my build right the first time. Your build threads have always been a treat for me, and I actually understand what you are doing and why, not so much with some of the other threads on TRF.
Keep up the great work, I'm an avid follower.

JordanT said:

I ask because I'm the guy who will carefully measure and match fit everything, only to find in the final assembly that I'm a couple of hundredths off - always in the wrong direction. Bonding the retainer body so early just seems like a recipe for disaster in my shop.

.

Click to expand...

Ya know I read this a couple of times & it began to eat at me. So I went back & checked, more than once, this morning it hit me.......


......I screwed up, did a real bone-head thing....forgot about snap-ring motors [AMW Gorilla & EX stuff]... That's what the little thin ring is for!

Jordan.......YOU WERE RIGHT.....

CTI fits great.

AT fits great.

AMW...uh-oh.

EX ...uh oh..

I guess it's time to go get some new Loki 54mm cases? They have smaller snap rings closer to the back of the motor.

blackjack2564 said:

Alrighty then... we have now officially finished with the fincan & can start assembly!

]

Click to expand...

No were not!

I forgot to fit using the ringie thingie!

If you are not going to ever use snap-ring motor it doesn't matter....but if you are:

Slip it over motor then insert, screw on your retainer cap, THEN fit to airframe.

You can see the difference in all 3 types of motors.
There rear closures are spaced a tad different than snap ring motors thrust ring.
AT & CTI are the same.

Thrust ring is set lower into case/snap ring motor, when installed and cap screwed on....ya now have that gap.

You can see here, how the ringie thingie accounts for that & makes them all = fitting.

Jordon... thanks so much for the heads up. Ya saved my butt! Went back & re-adjusted so now all motors will fit.

Now I'm ready to glue it all together!

Wayco said:

Your build threads have always been a treat for me, and I actually understand what you are doing and why, not so much with some of the other threads on TRF. great work, I'm an avid follower. [/SIZE][/SIZE][/FONT]

Click to expand...

Thankyou. They may get a bit wordy in places, but I try to explain all the reasoning for doing something a certain way, thus answering most questions before they are asked.

CarVac said:

I guess it's time to go get some new Loki 54mm cases? They have smaller snap rings closer to the back of the motor.

Click to expand...

If ya don't do anything bone-headed like I did you'll be alright. Ya Scott is making some nice stuff with LOKI. Been hearing some great things about them,I'll have to try some myself.

But that is cool if they are spaced the same as AT & CTI, one less thing to worry about.

Alrighty then,back on track...

Before I glue my MM assembly into place:

I want to use the fin slots as a marking guide on coupler for rivet positions.
Later when time to drill holes for the 3 rivets that will hold the coupler/av-bay in payload, I will have nice marks equally space 120 around the coupler.

Slide coupler into fincan part way, and mark through all the slots .
You now have positions for rivets or screws, whichever you intend to use for future attachment point.

Anyone needing eye nuts check this listings:

https://www.ebay.com/itm/Stainless-...626?pt=LH_DefaultDomain_0&hash=item27cb321152

https://www.ebay.com/itm/Stainless-...935?pt=LH_DefaultDomain_0&hash=item27cb2a7937

jus_rockets said:

Anyone needing eye nuts check this listings:

https://www.ebay.com/itm/Stainless-...626?pt=LH_DefaultDomain_0&hash=item27cb321152

https://www.ebay.com/itm/Stainless-...935?pt=LH_DefaultDomain_0&hash=item27cb2a7937

Click to expand...

Thanks for that link, I'm sure many will appreciate it!

Anyone else have any good info or helpful tips that might help your brother fliers.....speak up. I'm sure there are a lot of new guys following this who would appreciate it.

I'm going to tack my fins on & here is a paper guide PDF, posted below, I used to make my wood one. Don Ball made this for me....the Wildman logo is on the corner but there is no connection to him.... or accuracy...just so ya know. When printing it out, make sure you are at 100% so it's accurate. Even then, check the size with a tube or ruler & adjust the print size to get it right. I think I had to go to 104% on my printer.

Here is another link that shows how to make good cardboard ones also....besides that, this site is a blast to read over when you have some spare time. These guys used to be very active in rocketry & had a site with tons of useful information & just plain fun to read. Vatsaas Bros.

https://www.vatsaas.org/rtv/construction/finjig.aspx

Check out the Misse-aneous tab if ya want some good laughs!https://www.vatsaas.org/rtv/misc/misc.aspx
.........................................................................................


Ok..... let's continue on.

I mixed up some JB Weld only because I have it on hand. 5-10-15 minute is fine for tacking the fins in place.

I then use the tip of mixing stick to "butter" the root of fin. You don't need much, just a thin bead of glue along this edge.
It's only in the slot so I can take a picture, usually just hold it in hand.

View attachment 3FinGuide copy.pdf

jus_rockets said:

Anyone needing eye nuts check this listings:

https://www.ebay.com/itm/Stainless-...626?pt=LH_DefaultDomain_0&hash=item27cb321152

https://www.ebay.com/itm/Stainless-...935?pt=LH_DefaultDomain_0&hash=item27cb2a7937

Click to expand...

Oooh nice. I always forget about eBay.

I'm Tacking on the bottom 3 fins first.
They are closer to bottom of fincan thus easier to align.
After they are cured, I will use them to align the upper 3 fins. So....

Stick'em in the fincan[numbered fin to numbered slot], use the lines I drew to make sure they bottom out to motor tube & are nice and snug. I just eyeball them from the top with the fin-guide. If you got a cool method, tell us about it.

After I put the eyeball to them, I use a drop of CA to hold them in place....just a drop.
Got tired of checking on them, to see if they slipped or moved while glue is curing.
They are not going anywhere, once locked in place with a dab of CA.

Green Jello said:

When you tack on the rings with CA, do you use thin or the thick gel stuff?

Click to expand...

Thin, cause it's what I have. It will wick into places, & that's all I use it for, until I glue.
I have never used the thick stuff so can't offer an opinion.

blackjack2564 said:

Anyone else have any good info or helpful tips that might help your brother fliers.....speak up. I'm sure there are a lot of new guys following this who would appreciate it.

Click to expand...

Absolutely. I'm quietly listening to all of this. This is my first batch of fiberglass rockets ( Darkstar, Jart, mini claw, and a RW lil' rascal) I'm building the Jart first to get a feel for things. There's much I still haven't decided on, such as injecting or pulling the rear CR, However I'm absolutely going with the setup you used on the nosecone. Thanks for posting, and trust me, definitely not falling asleep!

I've tacked on a minimum diameter fincan with the thick stuff before applying big carbon fillets, but the gel-like stuff takes forever to fully stiffen up and it spoiled the bond with the tube somehow, so a fin came off on landing.

That's why for my final one I'm using Aeropoxy ES6209 for "tacking" as well as the subfillets. Aided by my 3d-printed fin guide.

CarVac said:

I've tacked on a minimum diameter fincan with the thick stuff before applying big carbon fillets, but the gel-like stuff takes forever to fully stiffen up and it spoiled the bond with the tube somehow, so a fin came off on landing.

That's why for my final one I'm using Aeropoxy ES6209 for "tacking" as well as the subfillets. Aided by my 3d-printed fin guide.

Click to expand...

Just to be clear.......
Keep in mind I used JB to tack, once placed into the fincan, the Ca was used[just a drop] on the tube to fin seam to lock it on place.
I also had bad luck tacking fins onto a minimum & I won't do it anymore either. [Lessons learned the hard way.LOL]

blackjack2564 said:

Jordan... thanks so much for the heads up. Ya saved my butt! Went back & re-adjusted so know all motors will fit.

Click to expand...

I'm a newbie to anything bigger than 29mm, most of what you just said was Greek. Or Italian. Or German. Heck, it might have been Sumarian. I'm going to have to digest all of that later...

[edit - just saw the post where others can get the 75mm motor in the un-slotted end, but not in the slotted end]

JordanT said:

most of what you just said was Greek. Or Italian. Or German. Heck, it might have been Sumarian.

Click to expand...

Please.. if something is not clear or confusing, ask & I will clarify. Most of what I said about which section of build?

..........................................................................................................................................

The bottom set is cured after tacking in place.
I will use them to align the upper fin set. These I do 1 at a time.

Using any type of clamp you may have on hand... clothspin, chip clip, small clamps etc. plus straight edge....mixing stick, epoxy or paint, pencil, ruler etc.
I used clothspins and mixing stick

Once again butter root edge of fin with epoxy and set into slot.
Make sure fin is seated tight to motor mount. I used the previously drawn lines. [post 151 above, top of page] to check.

Clamp upper fin in alignment with lower using stick and clamp. Set aside till epoxy cures
Rotate & repeat for other 2 fins.

You can see using this method yields perfectly aligned fins. [assuming your stick is straight LOL]

JordanT said:

edit: I still am awaiting my order...though now I wonder if I should cancel the 75mm casing set since it's not going to fit in this and I don't have any other use forit.

Click to expand...

That's the only special I wish I had added to my order.


Jim looks great. I always lose the little rings. Iv never flown a snap ring motor before so I guess I don't need them. (No snap rings in Commercial California)

Please.. if something is not clear or confusing, ask & I will clarify. Most of what I said about which section of build?

Just the whole snap/thrust ring shifting out stuff. I even took out the tailcone retainer I bought with the kit to look at the pieces. Not only don't I have a snapring case, I don't own a single 54mm case, so I don't have any hands-on with the normal assembly process. I went back and re-read (several times), and then re-read the directions on the retainer. I'm just going to make sure I have the necessary clearances for the retainer and post-fit it, just to be sure. I think I'm in good shape...carry on.