Quoted from Goffa

guess other options are a "proper" forged eyebolt or a Ubolt.
I wonder what is the "weakest link in the recovery chain": shock cord, quicklink, eyebolt, BH, CT, rivets?

all of the above is the weakest link

i must admit i dont like the look of the those eyebolts forged would be better or say some ubolts

your build so far is top notch Goffa

Here is the 1st set of external fin fillets. Doing 2 at a time.
Mixed Wests epoxy..quite runny... thickened up with 406 filler until "peanut butter"
Masked off fin areas, applied thickened epoxy and smoothed out with a piece of 1" dowel dipped in metho.



Pretty happy with these 2 ...looks nice an aerodynamic.

goffa i recieved my carbon fiber the other day and it looks nothing like the stuff you have, mine is more like a powder

Quoted from DAZZA98

goffa i recieved my carbon fiber the other day and it looks nothing like the stuff you have, mine is more like a powder

wonder if its actually graphite powder?
I've got more CF than I can use...only need a few tea spoons for a whole build...you are welcome to some if you want...send me a PM.

WOW Goffa I have just read your build thread. Awesome stuff and some great tips along the way.

You have definately set the bar high for any level 3 builds that will follow in the coming years.

I cant wait to see this rocket fly.

Best of luck.  

Quoted from wolfies gurl

WOW Goffa I have just read your build thread. Awesome stuff and some great tips along the way.

You have definately set the bar high for any level 3 builds that will follow in the coming years.

I cant wait to see this rocket fly.

Best of luck.

Thanks wolfies gurl!
My wife can't wait for me to finish the damm thing...spending lots of nights in the shed!

I've read a few really high quality L3 build threads on USA sites...
Then the final post is very short...cato...shred

Well the booster section build is nearly complete now...all the external fin fillets done.
The booster section was cut into 42+12 for shipping...so I still have to couple these together to make a 54" section.

Rocket survived its first big test on the weekend...an inspection by RocketBallSA!
What RocketBallSA didn't tell me was his method of inspecting is basically to grab the fins and try as hard as he can to rip them off  
He started with headlock then moved onto full nelson, half nelson, arm bar, indian leg lock, abdominal stretch and then finished with sleeper hold  

Chutes arrived the other day:
- SkyAngle Classic II 60"
- SkyAngle Cert3 drogue 24"

The SkyAngle chutes are more expensive than e.g. TopFlight but I read so much about them..that I just wanted to get them...
They claim that their extended panel design means that they can achieve descent rates with a smaller diameter.
Was worried that an 80" traditional design chute might not fit in my "small" 4" diam 24" length payload tube.
Like the idea of only 3 shrouds..less chance of tangle.
Also they come with a swivel.

Specs for the Classic II 60"
- 1.9 oz. silicone-coated balloon cloth
- 3/8" mil-spec tubular nylon (950 lbs.) suspension lines (3) sewn around canopy
- 1,500 lb. size 12/0 nickel-plated swivel
- 17-25fps descent rate for rockets weighing 10-22lbs 4.5-10kg

This rocket will weigh about 8kg on descent.

Drogue is small but super strong.
- 1.9 oz. silicone-coated balloon cloth.
- 5/8" mil-spec tubular nylon (2,250 lbs.) suspension lines(3) sewn around outside canopy.
- 1,500 lb. 12/0 nickel-plated swivel




Had a test packing of the main + shock cord + quicklinks into the 24" payload section to make sure it would fit ok.
Seemed to fit pretty well but only just...

Quoted Text

Rocket survived its first big test on the weekend...an inspection by RocketBallSA!
What RocketBallSA didn't tell me was his method of inspecting is basically to grab the fins and try as hard as he can to rip them off      
He started with headlock then moved onto full nelson, half nelson, arm bar, indian leg lock, abdominal stretch and then finished with sleeper hold   

lucky Wolf's not testing it... i heard he backs over them with his car

All fixed Goffa.

Thanks star destroyer! much appreciated. Must have been a pain to restore.

good work team!

how's the build going, goffa? much progress since you last posted?

Hi Mr F.
Lots of thinking...not much progress for a while but finally got a lot done on my day off today.

booster tube
The booster airframe was 54" but arrived in 2 pieces (42+12) for shipping.
Was wondering whether to add the extra 12" to the payload section or the booster section.
Once i had proved that the Skyangle 60" chute fitted ok in the payload section (just) I decided to add the 12" to the booster section to allow for future possibility of hybrid flights.
Would like to get into hybrids one day and a 54" tube would accommodate a Skyripper 54mm motor or a Contrail 75mm motor.
Here you see the 54" booster section: 42 + 12 joined with a 12" coupler.


Avbay bulkhead
Have been a bit worried with the welded eyebolts I got for the avbay bulkheads.
They are probably strong enough but they look ugly.
So I ordered some forged stainles steel eyebolts from Commonwealth displays.
But the thread on them were not quite long enough to go through the stepped bulkheads with the nice big trailer washers that I wanted to use.
So I ended up doing what Wolflair knew I would do all along...want back to U-bolts
It seems the closer you get to flying the more you start getting nervous about whether components are strong enough!

Here is how I have ended up doing the avbay bulkheads:
- Shock cord mount: Stainless Steel U-Bolt
- Eject canisters: PVC Pressure pipe
- terminal strips: jaycar
- allthread rods with nice big washers
As will be running dual altimeters need dual canisters and terminal strips.


For the eject charge canisters I used 15mm PVC pressure pipe.
Cut 1" lengths then poured a 1/4" of wests epoxy/chopped Cf into the bottom to make a cap.
Then drilled a hole and countersunk and screwed in a 1/8" bolt thru the bulkhead and a nut.
These will take about 5g of BP...more than enough for my needs.


The terminal strips are also thu-bolted into the bulkhead.
Then drilled a hole for the eject charge wires...the hole will be epoxied up.





Avbay sled
Epoxied 1/4" launch lugs onto the the avbay sled to act as rails for the allthread rod.
The painted the lugs with epoxy and applied fillets to the sled/lug join.




Nosecone bulkhead
Was wondering whether to build a removable bulkhead for the nosecone in case I wanted to add a tracker in the future.
But decided in favour of KISS in the end and just epoxied it in.
If I want to go down that track later I can always cut out the bulkhead and start again.

Used one of my forged eyebolts for the NC bulkhead. Fits pretty well here.
Use a nylock bolt and added a dab of epoxy for good measure.
Tacked the nosecone bulkhead with wests/chopped CF.





Then after cured poured a nice big fillet of epoxy/CF onto the top.


MMA5
Got a LOC 38-75mm adapter.
It seems to fit quite well with the RA75 motor retainer.
Have decided that the 1st shakedown flight will be on a J350W.
It will be nice low 1kft flight so I can have a good look at how it flies.
Will do dual deploy with the main at apogee and the drogue at 300ft.

Altimeters
I already have a PerfectFlight MAWD. That will be the primary.
Finally decided to go with the Missleworks RRC2-Mini as the backup altimeter.
Mainly just wanted to get something that was simple, cheap and well proven.
The MAWD has proved very reliable and it does logging (20 samples per sec)
The RRC2-mini is a bit cheaper as it only stores maximum values. But it does have some good features such as ability to change the chirping frequency that make it a good choice in a dual altimeter configuration.

Switches
Have been looking around on the net for HPR-proven switches.
I like the screw down types and the slotted rotary types as sold by Binder(WRL), Aerocon and Missleworks.
As I was ordering the RRC from Missleworks it was easiest to get the switches and misc mounting hardware as part of the same order.
The switches they supplied are slotted rotary type with high detent spring loaded cams for bobble-free operation by flat-blade screwdriver.

Switch mounting options are:
- internal: on the sled mounted on a bracket for access by poking a screwdriver through the port holes.
- external: on the airframe switch band

Internal mounting was a bit too tight for my 4” coupler so it had to be external.
Next big problem: how to drill ½” diameter holes in 3/8” thick fiberglass without making horrible splinters! Gahhhh!!!
I had read a bit about how careful you have to be drilling into fibreglass because it splinters easily. It seems the idea is to go slow and gentle, starting with a 1/16” drill bit and moving up incrementally through all the bit sizes. That has worked well up to ¼” as I have a full set of bits in that range. But ½” is a big step up.

It was at this point that the internal alarm bells started sounding…you are gonna stuff this up…get advice from someone who has done this before!!
Anyway I didn’t stop and wait for advice and it was only dumb beginners luck that I ended up making only a small mess!

So if anyone knows how to do this properly…please advise even though its too late for me!

Here’s how I bungled through it.
I stupidly thought that a timber spade drill bit would do the trick. So drilled a pilot hole and tried the ½” spade bit but only succeeded in making a ½” diameter furrow. Luckily my next door neighbor turned up to have his usual laugh at my handyman ineptitude and he returned with a proper ½” bit. So I drilled up to ¼” and then used a hand reamer to extend out to ½”, then used the ½” bit to clean up the hole. As it turned out the spade bit was a dumb but lucky mistake as the furrow helped to minimize splinters. For the 2nd hole I didn’t use the spade bit and got a few more splinters.

Here’s the hacked holes, splinters and all.


Doesn’t look so bad with the switches installed.




Wiring
Will need pairs of leads for altimetersx2 to terminalsx4, switchesx2, batteriesx2
Tinnng the leads.


Here’s the leads installed to the terminal strips with the holes epoxied over.
Also added a dab of epoxy onto the screw heads inside the canisters just to protect the igniters.

SPADE BIT Nooooooooooooo lol you got there in the end i like to use a brand new drill bit and just take it slow and steady