# Thales Starstreak build

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#### Mike Haberer

##### Well-Known Member
TRF Supporter
If there are issues with the CG/CP locations due to having to add weigh to the nose because of the canards, you could include induction stabilization to the mix (recess the motor mount to get gas-dynamic stabilization). it would be an interesting technical problem to figure out the relative stability provided by the fin/canard configuration with the induction stabilization.

#### Ez2cDave

##### Well-Known Member
TRF Supporter
Have searched all web-sites of local providers of poster/mail tubes - I can't easily get 125mm (5inch) ID tubes easily, unless I fly to Melbourne and pick them up!
You might try calling local Architects or "Reprographics" businesses ( probably called something else in Australia ) . . . Since they work with large drawings / blueprints, on a regular basis, they might have some spares lying around. Alternatively, they might be able to order them for you.

Some other possibilities :

https://www.gumtree.com.au/s-brisbane/mailing+tubes/k0l3005721

https://www.uline.com/BL_3704/Jumbo-Kraft-Tubes

Dave F.

#### BrendanH69

##### Well-Known Member
TRF Supporter
You might try calling local Architects or "Reprographics" businesses ( probably called something else in Australia ) . . . Since they work with large drawings / blueprints, on a regular basis, they might have some spares lying around. Alternatively, they might be able to order them for you.

Some other possibilities :

https://www.gumtree.com.au/s-brisbane/mailing+tubes/k0l3005721

https://www.uline.com/BL_3704/Jumbo-Kraft-Tubes

Dave F.
Thanks Dave. Been through all those sites and (mostly) adverts that lead you nowwhere. Most end up at the easy to get 60mm and 90mm sizes, but no 100mm nor 125mm sizes. Reprographics and architects are worth a go next. Trying to avoid US$70+ shipping costs or US$70+for a min order of 15 tubes, otherwise I might as well buy a 60inch length of 5inch airframe from Madcow!
Need to explore the USA shipping forwarders though as might need to use this in the future.

#### Ez2cDave

##### Well-Known Member
TRF Supporter
Thanks Dave. Been through all those sites and (mostly) adverts that lead you nowwhere. Most end up at the easy to get 60mm and 90mm sizes, but no 100mm nor 125mm sizes. Reprographics and architects are worth a go next. Trying to avoid US$70+ shipping costs or US$70+for a min order of 15 tubes, otherwise I might as well buy a 60inch length of 5inch airframe from Madcow!
Need to explore the USA shipping forwarders though as might need to use this in the future.
Another option is "rolling your own" . . .

https://www.instructables.com/Make-your-own-Kraft-Paper-Tubes

Dave F.

#### BrendanH69

##### Well-Known Member
TRF Supporter
emailed several reprographics shops in Brisbane to try my luck on 125mm and 100mm tubes.

#### Ez2cDave

##### Well-Known Member
TRF Supporter
emailed several reprographics shops in Brisbane to try my luck on 125mm and 100mm tubes.
I wish you success !

Dave F.

#### BrendanH69

##### Well-Known Member
TRF Supporter
No luck yet from the emailed queries - all were a blank on the size.

Went to a local picture framing company and scored a few tubes:
• a nice lightweight thin wall 154mm ID tube 70cm long (total weight 270gms).
• a thick wall 125mm ID tube 94cm long (840gms).
• a thick wall 100mm ID tube 122cm long (770gms).
The lady said she threw loads of them out on Saturday. Will go back for more I think!

#### Ez2cDave

##### Well-Known Member
TRF Supporter
No luck yet from the emailed queries - all were a blank on the size.

Went to a local picture framing company and scored a few tubes:
• a nice lightweight thin wall 154mm ID tube 70cm long (total weight 270gms).
• a thick wall 125mm ID tube 94cm long (840gms).
• a thick wall 100mm ID tube 122cm long (770gms).
The lady said she threw loads of them out on Saturday. Will go back for more I think!
On an "upscale", the 154mm tube, depending on its Outside Diameter, would make the Darts 1.25" ( 32mm ) diameter ( BT-55 Coupler ) !

Dave F.

#### DrewW

##### Well-Known Member
Made a little more progress on a first dart tonight but realized two things...

First, I needed to make some modifications to the dart design to allow better free rotation of the upper section and to correct for final mass and positioning of elements for Starstreak Dart prototype (SDP) 1

Second, I'm thinking I need to find a fly away rail guide (picture from Apogee Components below) with a 24mm to 32mm stand off which is much larger than I can find on the internet for a 24mm OD rocket. Maybe I need to go visit my local rocket shop and get some custom 3D print work done...

The reason for the stand off is because I need free rotation of the upper canard section during boost. If I use rail buttons or a launch lug I need a pretty significant stand off which throws off the scale aesthetic. If I use a standard set, the canards have a max rotation of about a quarter turn until they leave the rail...this could be "bad". I looked at short rods/rails similar to how I expect the full unit to fly from an already moving bus vehicle, but there isn't enough velocity off the rod without using an AT D21 motor and sending this well over 1000 ft, which is just a bit too high for the field and conditions I'll be flying to do initial test flights.

Final alternative, which happens to solve several immediate challenges simultaneously is to find someone already making a fly away rail guide, or find someone to make one for me.

#### Ez2cDave

##### Well-Known Member
TRF Supporter
. . . but there isn't enough velocity off the rod without using an AT D21 motor and sending this well over 1000 ft, which is just a bit too high for the field and conditions I'll be flying to do initial test flights.
Simple solution . . . add a removable "Drag Plate" ( Disk ) to the rear of the rocket. The additional Base Drag will reduce the Altitude reached. Since it is removable, it will not "look funny", when the rocket is on display !

Some "background info" . . . https://www.rocketryforum.com/threads/variable-drag-project.157027

Dave F.

#### BrendanH69

##### Well-Known Member
TRF Supporter
Still waiting for the arrival of my first order of build parts for the Darts from the supplier in New Zealand. Despatched 17Nov. Lack of international flights due to Covid restrictions is the likely issue.

#### DrewW

##### Well-Known Member
Simple solution . . . add a removable "Drag Plate" ( Disk ) to the rear of the rocket. The additional Base Drag will reduce the Altitude reached. Since it is removable, it will not "look funny", when the rocket is on display !

Some "background info" . . . https://www.rocketryforum.com/threads/variable-drag-project.157027

Dave F.
@Ez2cDave I’ll end up using this idea somewhere else, but because I’m trying to make sure the CP aspects of the model work when the front half is spinning and the other half is not, this would over stabilize the rocket.

Great idea though. And I just found a cable spool at work that was being discarded. Going to turn it into my first base drag experiment and run from there.

#### BrendanH69

##### Well-Known Member
TRF Supporter
Bought a foodsaver vacuum appliance and got started at making some sheet stock for fins and canards. Used 3mm plywood as the core and laminated it with 2 sheets of FG each side - 1 of 200g/m2 and 1 of 135g/m2. Will let it cure a week and will cut it only when I get my BT50 and nose cones.

#### BrendanH69

##### Well-Known Member
TRF Supporter
Finally received various build parts from the supplier in New Zealand. Took 2 weeks for the delivery to get here, but that's consistent with today's standards.
Started laying out and judging scales for the Dart bodies (BT50 tubes), Nose cones (PNC50) and the templates for the canards and fins.
Will begin over Christmas by rolling the BT50 tubes in a wrap of fibreglass to stiffen them a bit and by making some canards and fins from laminating 2.7mm ply with F/Glass. The body tubes will get cut down to 380mm long, giving a tip to tip length of 450mm for an estimated 114% scale.

Tweaking the design a bit too. Want to make the fin can removable, and to have that step down in body diameter the real thing has on it to recess the pop-up fins. Initially going to build it with through the wall fins, but want the ability to remove the fin can to upgrade to pop-ups if I ever go down the route of a tube launcher. It will create a stress weak point though, so will have to overbuild in the area I think.

#### BrendanH69

##### Well-Known Member
TRF Supporter
Started work on the Darts today.

Gave the BT50 tubes a wrap of 135g/m2 F/Glass to stiffen them. The yellow material you see them wrapped in is rip-stop nylon - I use it as my "poor man's peel ply" as... a) I can get it easily ..... b) it works fairly well ..... and c) it only cost me about AU$2.5 per linear meter when discounted. The roll is 1.5m wide too!! Used half a A$2 broomstick as a mandrel for supporting the tubes while I rolled them. Not the best of F/G wrap jobs I'll admit, but its good practice and will do well enough after a bit of filling and sanding. Will let them cure for a few days before cutting to size and contemplating fin slots.

Spent the the rest of the day cutting canards and fins to my template out of 3mm plywood on the table saw and then marking them out for bevels. Did the bevelling on the belt sander and using my 10degree platform jig screwed to the side of the belt sander.

I'm intending on installing the canards with some tip to tip F/Glass. The fins will be through the wall onto the 18mm motor tube.

I received a delivery of Estes 18mm engine mount kits. After a trial assembly, I'm not happy with trying to use the classic engine retainer hooks as there is too little clearance to push it over to get the motor out. Ideally I would like to go for Estes 3187 18mm screw on retainers as they would also sit nicely against the booster transition too. However, can't seem to locate a supply in Australia or NZ, so USA /eBay suppliers are likely 2 months away and mega shipping costs again. Ideas? Options?

#### BABAR

##### Builds Rockets for NASA
TRF Supporter
Little bit late to the party, but some ideas.

Most of the MIRV type rockets I have seen (single booster, multiple sustainers) have had sustainers that were not stable. Attitude seemed to be, “they launch up around 100 to 200 feet, they aren’t going to go far especially if they ARE unstable, who really cares.” I am pretty sure the Estes MIRV sustainers were NOT independently stable, I applaud you in making yours stable, I like you am a purist that figure having them stable is more realistic.

Not sure how doable it is (maybe with 3D printing), but perhaps a rail built into the center between the sustainers might work better than rods and be easier to “hide”.

Using friction fit for the sustainers, leaving an external portion of the sustainer motors to “nest” into appropriate “receptacle tubes” in the booster may provide a more secure stack on boost phase. If you use streamers for booster recovery (you’re gonna have lots of parts to track in recovery, streamers drift less and are sometimes easier to see in the air and on the ground than chutes, particularly if brightly colored. You can also pack an extra long streamer in less space than a regular chute, the extra length beyond the classic 1:10 ratio doesn’t do much for increasing drag but does a lot for visibility, especially in trees or bushes) the butt end of the protruding engine survives a faster landing impact than some motor retainers.

Wishing you multiple straight trails!

#### BrendanH69

##### Well-Known Member
TRF Supporter
Little bit late to the party, but some ideas.

Most of the MIRV type rockets I have seen (single booster, multiple sustainers) have had sustainers that were not stable. Attitude seemed to be, “they launch up around 100 to 200 feet, they aren’t going to go far especially if they ARE unstable, who really cares.” I am pretty sure the Estes MIRV sustainers were NOT independently stable, I applaud you in making yours stable, I like you am a purist that figure having them stable is more realistic.

Not sure how doable it is (maybe with 3D printing), but perhaps a rail built into the center between the sustainers might work better than rods and be easier to “hide”.

Using friction fit for the sustainers, leaving an external portion of the sustainer motors to “nest” into appropriate “receptacle tubes” in the booster may provide a more secure stack on boost phase. If you use streamers for booster recovery (you’re gonna have lots of parts to track in recovery, streamers drift less and are sometimes easier to see in the air and on the ground than chutes, particularly if brightly colored. You can also pack an extra long streamer in less space than a regular chute, the extra length beyond the classic 1:10 ratio doesn’t do much for increasing drag but does a lot for visibility, especially in trees or bushes) the butt end of the protruding engine survives a faster landing impact than some motor retainers.

Wishing you multiple straight trails!
Thanks Babar.
Homemade streamers made from that neon yellow rip-stop nylon in the photo for the 3 Darts is a good idea, and I'll have a look at that, particularly if it aids visibility of multiple mid-air deployments around 1000ft.

Still mulling over my options for separation and launch of the Darts. I'm keeping my options open at the moment!

#### BABAR

##### Builds Rockets for NASA
TRF Supporter
Thanks Babar.
Homemade streamers made from that neon yellow rip-stop nylon in the photo for the 3 Darts is a good idea, and I'll have a look at that, particularly if it aids visibility of multiple mid-air deployments around 1000ft.

Still mulling over my options for separation and launch of the Darts. I'm keeping my options open at the moment!

Food for thought, however.

You aren’t going to win any altitude records, so I am guessing you are going for show, which is great!

This rocket would be cool even if it was just a single stage. Cool rockets don’t NEED to go very high, in fact, I don’t think getting them much over say 500 feet makes them any cooler, just harder to recover.

Going for single booster to multiple sustainers itself is (at least to me) super cool. The Estes MIRV was a cool concept and a great LOOKING rocket, unfortunately poorly executed mainly as booster severely underpowered.
I wonder if they will re-release it if/when they come up with a C5-0.

But in any case, the cool factor is diminished the higher the staging altitude. You WANT this to stage low, say 100 to 200 feet for at least two reasons, possibly 3.

1. You want to see (and those at your launch will want to see) this puppy stage. That will be clearly visible up to 300 feet. At 1000 feet it’s gonna be a little bit like the Saturn Jupiter conjunction, seen with the naked eye it was okay, seen through binocs or a telescope was more impressive.

2. You probably want to launch this more than once. I went to NSL hosted by ROC (kudos to them, BTW, was great) and they were nice enough to entertain us LPR mortals. I had a single stage intentional CATO recovery I built (google Estes CATO or see here
https://www.rocketryforum.com/threads/estes-cato-clone.126220/) that deployed at around 150 feet on flat playa and I STILL couldn’t find all the pieces, the smallest of which was about 10 inches in decorated with colored Mylar tape. There is a strong possibility that your multiple sustainers may deploy in a StarBurst maneuver, which will look cool but imagine three sustainers going in three different directions before deploying....... and then trying to track them. BTW, STRONGLY recommend you go with minimum newton motor for boosters. If your staging works, they are already at stable velocity when they stage, consider even DOWNSIZING a motor diameter with an adapter (like 18mm to 13mm 1/4A-3T. At least for first flight.)

Possibly 3. If you have tilt and altitude lockouts on your electronics you PROBABLY don’t need this. But @JimJarvis50 aside, the higher your booster goes, the more likely it will be something less than vertical at staging. Non-vertical staging, particularly if it is 90 degrees or more off vertical, is generally considered poor form, it is NOT the entertainment you want to see in person, nor (if your name is mentioned) do you want to see it later on YouTube. This is also why especially for first flights you should use small sustainer motors, if the light off vertical they won’t go as far and won’t have as much energy if there is fecal turbine interaction.

#### DrewW

##### Well-Known Member
Little bit late to the party, but some ideas.

Not sure how doable it is (maybe with 3D printing), but perhaps a rail built into the center between the sustainers might work better than rods and be easier to “hide”.

Using friction fit for the sustainers, leaving an external portion of the sustainer motors to “nest” into appropriate “receptacle tubes” in the booster may provide a more secure stack on boost phase. If you use streamers for booster recovery (you’re gonna have lots of parts to track in recovery, streamers drift less and are sometimes easier to see in the air and on the ground than chutes, particularly if brightly colored. You can also pack an extra long streamer in less space than a regular chute, the extra length beyond the classic 1:10 ratio doesn’t do much for increasing drag but does a lot for visibility, especially in trees or bushes) the butt end of the protruding engine survives a faster landing impact than some motor retainers.

Wishing you multiple straight trails!
That's essentially my plan. Looking at putting a button on each sustainer with a Y shaped rail 3D printed as part of the bus Pillar. Planning on friction fitting the base for alignment and to prevent drag separation prior to powered sustainer separation. I like the streamer idea, I have a local rocketry shop who will cut aluminized Mylar to request and will probably use some 20:1 ratio streamers for visibility.

#### DrewW

##### Well-Known Member

Food for thought, however.

You aren’t going to win any altitude records, so I am guessing you are going for show, which is great!

This rocket would be cool even if it was just a single stage. Cool rockets don’t NEED to go very high, in fact, I don’t think getting them much over say 500 feet makes them any cooler, just harder to recover.

Going for single booster to multiple sustainers itself is (at least to me) super cool. The Estes MIRV was a cool concept and a great LOOKING rocket, unfortunately poorly executed mainly as booster severely underpowered.
I wonder if they will re-release it if/when they come up with a C5-0.

But in any case, the cool factor is diminished the higher the staging altitude. You WANT this to stage low, say 100 to 200 feet for at least two reasons, possibly 3.

1. You want to see (and those at your launch will want to see) this puppy stage. That will be clearly visible up to 300 feet. At 1000 feet it’s gonna be a little bit like the Saturn Jupiter conjunction, seen with the naked eye it was okay, seen through binocs or a telescope was more impressive.

2. You probably want to launch this more than once. I went to NSL hosted by ROC (kudos to them, BTW, was great) and they were nice enough to entertain us LPR mortals. I had a single stage intentional CATO recovery I built (google Estes CATO or see here
https://www.rocketryforum.com/threads/estes-cato-clone.126220/) that deployed at around 150 feet on flat playa and I STILL couldn’t find all the pieces, the smallest of which was about 10 inches in decorated with colored Mylar tape. There is a strong possibility that your multiple sustainers may deploy in a StarBurst maneuver, which will look cool but imagine three sustainers going in three different directions before deploying....... and then trying to track them. BTW, STRONGLY recommend you go with minimum newton motor for boosters. If your staging works, they are already at stable velocity when they stage, consider even DOWNSIZING a motor diameter with an adapter (like 18mm to 13mm 1/4A-3T. At least for first flight.)

Possibly 3. If you have tilt and altitude lockouts on your electronics you PROBABLY don’t need this. But @JimJarvis50 aside, the higher your booster goes, the more likely it will be something less than vertical at staging. Non-vertical staging, particularly if it is 90 degrees or more off vertical, is generally considered poor form, it is NOT the entertainment you want to see in person, nor (if your name is mentioned) do you want to see it later on YouTube. This is also why especially for first flights you should use small sustainer motors, if the light off vertical they won’t go as far and won’t have as much energy if there is fecal turbine interaction.
I greatly appreciate the feedback and thoughts on this.

Regarding point (1) I think you're right, higher is not better in this case. I think though I'm going to aim for ~500' for staging so a chute on the booster has time to deploy and catch the booster which is going to weigh ~4-6lbs on its own.

Regarding point (2) With the close proximity of the three sustainers and nominally synchronized launch I think you have to have some minimal starburst effect to make sure they don't have a collision off their respective rails. But to your point I think 5º or less minimized the landing CEP. They should all return to earth in the same wind vector, as long as they're not gliders (ugh); here in Tucson very few trees and no hills on the range so hoping to recover with minimal frustration with sustainer apogee below 1500'.

Regarding point (3) I've thought about this a lot, I had a Boosted Bertha go nearly 90º at the last club launch because of a bad booster separation. Assuming the combined CP/CG relationships are safe, and that boost happens before apogee this shouldn't be an issue. But I have an earlier post where I mention the litany of small progressive steps I plan to make toward successful full up flight.

Interesting to note on the Starstreak, the darts on the real article are not boosted (as far as I've found) and rely on drag separation of the bus which has its own booster.

#### DrewW

##### Well-Known Member
Kind of fell off my crazed building schedule for a while with a few 80+ hour work weeks through December. And now taking advantage of my wife's offer to redo the workshop as I desire to make it more conducive to my projects rocket or otherwise. So fully taking advantage of that to build up some new mobile workbenches and dedicate some space to electronics and rockets rather than everything sitting on my miter bench with a 1x6 plank clamped to it to give me space to work around my projects.

Looking forward to getting a few small things done between now and going back to work on the 11th.

#### BrendanH69

##### Well-Known Member
TRF Supporter
Happy New Year!

Yesterday was spent tinkering and practicing with parachute making techniques on the new sewing machine. Sewing the shroud lines is tricky!

Made a start on the main Bus and the Booster body tube material by filling and sanding the spirals with carpenter's wood filler. Decided that they are rigid enough and should not need full F/Glassing for this project, but I still watched the John Coker "Glassing a tube" video for the pleasure of it! Might do some local reinforcement in a few areas later.

Having made that decision, I made a list of the plywood rings/spacers/bulkheads that this design is going to need and then got started into making some of the internal bulkheads and centering rings. Used the Dremel circle cutting/routering guide for the first 4, but that proved to be more effort than it's worth for even with the 7mm plywood and so I resorted back to the tried and tested "draw it with a compass, rough it out on the table saw" technique and then I used my recently made disc-jig with the bench top sander to finesse them down to final OD size. Will have to cut the centre holes next and then hand sand those with the Dremel down to final ID for the 38mm MMTs.

Next step after making the rings and spacers will, I think, be cutting the body tube materials to length while selecting the best bits of them and keeping some bits for making couplers from them. Don't have a drop saw, but the neighbour might have one big enough!

Need one coupler piece to make an AV bay and "nose cone" shoulder, probably.

#### BrendanH69

##### Well-Known Member
TRF Supporter
@BrendanH69

To your point on the ejection charge timing, I could use a timer for a BP initiation generating enough gas to drive separation, maybe something like this spider design. Alternatively, using motor ejection, if the coast time is going to be sufficiently long I just need to pick a motor ejection time that has enough margin to support a charge 2 seconds later than planned. After apogee would be unfortunate and would seem unsafe.
Just re-read your earlier post and looked at the spider design you referenced. Interesting. Missed that before. A spider system in the nose/Dart carrier could be a simpler, 1 BP charge does both the Dart motor ignition and get them moving away from the Bus.

#### DrewW

##### Well-Known Member
@BrendanH69 Happy New Year! How do you like the plunge router attachment for your Dremel? Was thinking about getting one the other day but wasn't convinced.

#### Ez2cDave

##### Well-Known Member
TRF Supporter
I think though I'm going to aim for ~500' for staging so a chute on the booster has time to deploy and catch the booster which is going to weigh ~4-6lbs on its own.
Chute sizing :

4 lb - 56 inches

5 lb - 64 inches

6 lb - 72 inches

https://www.rocketreviews.com/index.php

Dave F.

#### BrendanH69

##### Well-Known Member
TRF Supporter
@BrendanH69 Happy New Year! How do you like the plunge router attachment for your Dremel? Was thinking about getting one the other day but wasn't convinced.
Hi Drew.
Up to now, I have used the Dremel plunge router attachment mainly for cutting slots in body tubes for fins. It works reasonably well, but I now think the Dremel is a too lightweight for routing thicker and tougher materials, like thicker body tube materials and the 7mm plywood circle cutting I was using it for the first time yesterday.

With yesterday's task, it "chattered" about too much, and when combined with the amount of play it has when screwed into the router guide, it was giving a very inaccurate OD compared to what I was expecting, even when doing multiple shallow cuts. Then, after a short time even the Dremel quick change chuck loosened and the router bit pushed up into the chuck and stopped cutting. This didn't cause much workmanship issues, just added considerably to the job time having to stop and re-do it all back up.
The other disadvantage of the Dremel router guide, for when trying to cut circles, is that it can't cut any circle less than about 68mm in diameter, so I can't use it to cut the inner holes for my motor mount tube cantering rings for the 38mm MMT. Back to hole-saw bits or jig-sawing again!

Based on my experience and assessment, I'd say your doubts about the router guide may well be warranted. Still love my Dremel though!

For the next fin slotting tasks, I'm now thinking of adjusting my fin slotting jig to receive the base of my small Ryobi cordless router instead and see how that compares with it's larger shank and chuck size. It's a simple adjustment that I'd expected to do one day and just involves moving the two sides inward.

#### BrendanH69

##### Well-Known Member
TRF Supporter
Did a lot more building activity at the weekend due to Covid-19 induced 3-day hard lock-down for the greater Brisbane area, cancelling everything including our first scheduled QRS launch day for 2021.

Cut the various tubes to size, made multiple centering rings for the main Bus and the Booster motor mounts, inner spacer rings for the fin can mounting, several outer space rings (150mm OD). No CNC or lathe here, so everything done old school with compass, jigsaw and sanding jigs.

• Main Bus body is 134mm OD, 600mm long and weighs 553gms.
• Fin Can body is 106mm OD, 190mm long and weighs 130gms.
• Booster body is 134mm OD, and weighs 242gms.
• 38mm motor tubes. Sized for 1G CTI reloads in Booster, and 1G to 2G CTI reloads in the Main Bus.
• Spacer rings at 150mm OD, as well as giving the look of the real thing
(from a distance at least!) ,give options for a tube launch from a 154mm tube. Test fitted it in one, and looks good.
• Booster is intended to be motor initiated rear ejection recovery. Probably could've made the ejection tube smaller and more standard/round.
• Conduit is for running in the ignitor for future air-starts of the Main Bus motor. To be cut to size,
Lots of work yet to do. Next jobs:
• Make coupler tube for AV Bay & Nose cone.
• Cut fin slots for the Darts and Main Bus fin can.
• Consider & design the spider ignition system requirements for the "Hitiles" (Darts).
• Make one Dart assembly for scale trials.
• Make more fin material (F/Glass laminated 3mm ply).

#### DrewW

##### Well-Known Member
Alright, it's been a little while since I've made progress while I made some improvements to my garage work space while my wife was still in a giving mood. So I've spent some time working on how to get a 5" tube...turns out I didn't realize just how difficult a prospect this might be. First off I learned at length that there is a difference between tube and pipe. Tube is a nominal OD material whereas pipe is a nominal ID material (sort of)...who knew?!?

So I have scoured the internet looking for 5" tube (nominal OD), and have found some options but they are very expensive. So I started thinking about alternatives. Turns out that 4" pipe (nominal ID) has a wall thickness such that no matter the schedule it is usually 4.5" OD...Schedule=1000 * (Internal service pressure of pipe / ultimate stress of pipe material) ID appears to be based on Schedule 40 as a nominal. If I haven't put you to sleep yet, after all this research and pricing and sourcing thinking the thicker wall of a Schedule 80 pipe would solve my problems I realized I can just get a length of schedule 40 pipe from my local hardware store and use it as a mandrel. I'm going to try a ~0.25" wall thickness using base and top layers of kraft paper and using masking paper with alternating chirality for intermediate layers to lay up a body tube (weekend goals!).

I have a 4" pipe section and I need to yield a 32" section per my OR model, so I think I'll aim for ~36" and trim down as needed.

Also, a couple weeks ago I put in an order for a 3D printer after a decade of sitting on the sidelines, looking forward to it showing up so I can model and fab some of the other elements like the bus tower section.

Happy to be moving this forward again, members of my local club are interested in seeing the multiple sustainers releasing from the bus segment.

#### BrendanH69

##### Well-Known Member
TRF Supporter
Also, a couple weeks ago I put in an order for a 3D printer after a decade of sitting on the sidelines, looking forward to it showing up so I can model and fab some of the other elements like the bus tower section.

Happy to be moving this forward again, members of my local club are interested in seeing the multiple sustainers releasing from the bus segment.
I hear ya on the body-tube/pipe dilemmas!

My rocket buddy has been giving me jip for months about learning CAD and getting 3D printings and CMC/Cutting, but I've been resisting and doing the fabrication the old-school ways. It takes me longer doing it by hand, but it was taking me even longer trying to learn Fusion 360, and then they started making people pay for it!!!!

Finally got a club launch tomorrow morning - last one was 09Aug20!!
Got two new builds to make maiden flights with, so hoping it goes well. Spent most of the post-work time prepping for the launch rather than this project. Might also take the time to share the Starstreak plan and seek advice. Picking up my rocket buddy at 07:00 for the 50min drive to the launch site, and he just happens to have designed and got made a couple of simple dual deploy flight computers that need testing - cost about A$30. Still got a little bit of work done on the Starstreak - slotted the Bus fin can section. Used the Dremel again for slotting in the jig. It was OK-ish, but it still gave a few problems with the router bit dropping out occasionally. Maybe the quick change chuck is a bit worn. Also laminated another sheet of 3mm ply with two layers of F/G per side (1 was 200g/m2 and the other 135g/m2). Also made up a simple motor retainer for the Booster from a spare metal bracket and a nut insert - cheaper than using another A$45 Aeropark 38mm screw-on retainer.