"Mk4 Rocket Propelled Companion Pod" - SCR Quake L1 Build Thread...

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Its not pressure relief holes. It's sampling ports. I have only done it in three rockets, all are regular fliers. And none of them crashed, imagine that. My latest gave me a seemingly wonky apogee altitude but I have no other flight data for that rocket so it may have been accurate. I can't say what will happen when the rocket approaches Mach but for normal subsonic flights they will be fine in the nose cone itself or the shoulder. If going through the shoulder, pin the NC to keep it from turning and covering the ports.
 
NC seams filled and sanded with my favourite NC process: CWF and thin CA.

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One day I’ll figure out how to stop these divots happening with CWF...

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I think it’s the way I lay it down.
 
That is one of a few reasons I switched to papering for balsa fins... with CWF I'd always have some gaps like that. But I still use it for other stuff, and just deal with it. The good news is that it's pretty quick turnaround to add a bit more and sand it down again.

Those fillets are looking really great BTW.
 
That is one of a few reasons I switched to papering for balsa fins... with CWF I'd always have some gaps like that. But I still use it for other stuff, and just deal with it. The good news is that it's pretty quick turnaround to add a bit more and sand it down again.

Those fillets are looking really great BTW.

Lol - that IS the bit I laid down to address the divots in the layer below... ;-p




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Made a little more progress today.

Rail buttons and additional CRs (for NC AV bay) arrived from apogee.

First order was the aft rail button.

Drilled and fitted the rounded weld nut. I used a little epoxy clay on the inside to adhere it to the BT. I was working fast (small time window with the kids home on school vacation while I’m working) so no inside pics.

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Once the aft button was in, the rear CR was epoxied on.

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Tomorrow I’ll do the retainer. I’m going to wait till I see where the CG sits with the AV bay in the NC before I do the fwd rail button.
 
Tonight I started sanding down the CRs for the NC AV bay.

I have a question that I’ll get to at the end of the build steps that follow:

1) sanded down the 38mm ID on the CRs to fit some BT60 - it was a whisker and took 30secs with my dremel.

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2) I then turned my attention to the OD of the CRs to make them fit inside the NC above (fwd) and on (aft) the NC shoulder.

I used my patent pending “Peeling a Potato with a Dremel” technique. I also flattened them a little to make way for the mould join welds.
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3) roughed up the NC inside surfaces again with the Dremel and Dry Fit:
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And we get to the question:

I’m wanting to drill two holes in each of the CRs so I can pass a 2.5mm Kevlar loop up through both CRs as suggested in an earlier post. But I’m concerned there isn’t enough material to actually hold left in the CR.

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The fwd CR is down to less that 11mm each side and I’m going to be putting two ~2mm holes in them. They aren’t (supposed to be) load bearing.

The internal one is a little roomier with 12mm each side.

NC dry (no glue) but with electronics comes in around 150g.

What are people’s thoughts about it?
 
I’m wondering if anyone has some experience to share on the quandary I’m considering in the above post.

Perhaps I should post the question separately lest it be lost in my build thread?


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You're going to have an end cap for that bay yes? What prevents you from attaching your kevlar at that point?

I may not have the proper picture of how you're laying out your nose components.
 
Here is how I built mine. I did it pretty much how I showed you in the diagram...mostly.

Inner ring: I drilled the two holes so that the kevlar would clear the tube once it was in. Then brought them together with heat shrink. Since I got epoxy on my kevlar and couldn't pull the two ends to be more equal length or what not, I just tied a loop in the short end for attaching the chute and let the other end run long (about 18") and it will attach to the main harness.

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Outer ring: I just flattened one side with my belt sander and brought the straps out there. Sealed with epoxy glue. I put #6 weld nuts on the back side and epoxied them in place. My lid/sled will mount via the weld nuts.

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Other options you can utilize:
1 - Put an eyebolt in the inner ring on one side or both sides to attach you kevlar to. You would still have to run the kevlar through the outer ring.
2 - Put an eyebolt in the outer ring. When you step back and look at it this is the same method used on motor mount assemblies

FWIW. I had #4 wood screws in my inner ring, plenty of material to bite into. I pulled them out for now and will space them out a little neater before going back in with them. You can counter sink some into your outer ring through your shoulder if you feel it is necessary (yeah I know you said you didn't want to). My Cowabunga flies with only the outer ring held with epoxy and screws with the harness attached to it, no inner ring at all.

However you do it , just remember to leave enough material around the tube so you can get a good seal against ejection gases.
 
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You're going to have an end cap for that bay yes? What prevents you from attaching your kevlar at that point?

I may not have the proper picture of how you're laying out your nose components.

I pulled together the following drawings before the post below

OpenRocket004.jpg

OpenRocket006.jpg
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Here is how I built mine. I did it pretty much how I showed you in the diagram...mostly.

Inner ring: I drilled the two holes so that the kevlar would clear the tube once it was in. Then brought them together with heat shrink. Since I got epoxy on my kevlar and couldn't pull the two ends to be more equal length or what not, I just tied a loop in the short end for attaching the chute and let the other end run long (about 18") and it will attach to the main harness.

View attachment 334437

Outer ring: I just flattened one side with my belt sander and brought the straps out there. Sealed with epoxy glue. I put #6 weld nuts on the back side and epoxied them in place. My lid/sled will mount via the weld nuts.

View attachment 334436

Other options you can utilize:
1 - Put an eyebolt in the inner ring on one side or both sides to attach you kevlar to. You would still have to run the kevlar through the outer ring.
2 - Put an eyebolt in the outer ring. When you step back and look at it this is the same method used on motor mount assemblies

FWIW. I had #4 wood screws in my inner ring, plenty of material to bite into. I pulled them out for now and will space them out a little neater before going back in with them. You can counter sink some into your outer ring through your shoulder if you feel it is necessary (yeah I know you said you didn't want to). My Cowabunga flies with only the outer ring held with epoxy and screws with the harness attached to it, no inner ring at all.

However you do it , just remember to leave enough material around the tube so you can get a good seal against ejection gases.

Thanks - the images help.. I am just worried about the holes leaving the FWD CR ring (above the NC shoulder) too weak... hence my question on peoples thoughts...
 
I pulled together the following drawings before the post below

View attachment 334489

View attachment 334488
View attachment 334487





Thanks - the images help.. I am just worried about the holes leaving the FWD CR ring (above the NC shoulder) too weak... hence my question on peoples thoughts...

Understandable, but I don't think it will be much of a problem.
You can always just put one notch right next to the tube and epoxy kevlar right to the tube. Minimally invasive that way. Folks do it to MMT all the time.
 
Shock cord arrived today so I’ve been able to make some progress:

Printed up a template and drilled some holes for the AV bay cover lid. 4/40 T Nuts and knurled 4/40 hex bolts (still need to get some washers) selected. Not much room on the CR for the T-Nuts. I also don’t have a drill press so I’m limited to what I can do with either the dremel with pen extension or my hand held cordless. I chose the dremel. It’s hard to drill any kind of hole straight through two layers without a press.

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I undersized the last t-nut hole by accident on the last one of these three and actually managed to kill the t-nut. Luck I had one spare!

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Dry fit with the shock cord. I opted to use heat shrink to prevent epoxy on the shock cord as I glue bits together.

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Epoxy now setting on the fwd CR in the NC

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Filled the t-nuts with O-ring grease to prevent epoxy in the threads.

And final CR epoxied into the NC.

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NCAV bay filleted and finished.

I’ve left the BT60 insert loose - I like the option of being able to get back into the NC.

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Added the last rail button. I haven’t glued the inside on this one - it’s hard to get into the tube with a hand and I’m worried about accidentally epoxying into the tnut thread if I try to add epoxy on a long stick.

Time will tell if I’ll regret that decision.
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Retainer secured with JB weld after scoring the inside of the retainer screw and the MMT tube with a #11 to improve mechanical adhesion.

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JB that was squeezed out as I pushed and twisted the retainer on was then filleted with a glove (taking care not to foul the retainer threads.)

And with that done - construction as far as I can see is now done. I have 1/3 of the BT tube spirals to still fill / sand, otherwise she’s ready for primer and paint...
 
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Can of Bundy Rum and Coke for scale...




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Nose cone barometric sampling holes drilled at 120°.

Stopped with chopstick tips, masked and ready for priming.

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Nose cone came up brilliantly.

Two tone orange - one light one dark. (It’s not as red as that photo makes it look)

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Then, the mechanics of paining a BT vertically instead of my usual LPR horizontal process had me come unstuck... I got two coats of filler primer on just fine (with sanding in between) then the white primer coat I just put too much down. I have had the rusto process down pat previously and knew how much I could get away with, but the vertical orientation just meant I wasn’t as ready for where the paint was laying down with my strokes.

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So painting is now on hiatus while I wait for this coat to dry for a few days so I can sand the runs back and go again.
 
flat white sanded, fixed recoated...

gloss white went on today.. once I can inspect to ensure the gloss white is well coated, it's either more gloss white or blue fin painting time tomorrow...
 
This must be a closely guarded secret. Not even LOC, Binder Design, or Madcow know this. :wink: My level two was a paper bird.

A nose cone bay should be relatively easy. The same size centering rings that fit the rocket should fit in the nose cone above the shoulder, at least that has been my experience. You will have to chop the base off to get acess of course. Depending on how you want it installed and what not, you won't necessarily need a tube inside. I just happen to be working on a 2.6" kit myself and will be putting a bay in the nose cone.

JB Weld will work fine on the retainer for more than just a few flights. I've used it on several, still holding on.
Wood glue would be better on paper birds but 5-minute will work fine as well. You don't need Rocketpoxy on this bird. In three instances I have had the stuff let go, and it was just holding PEM nuts two of those times, 1/4" threaded rod the other. Maybe I got a bad batch but it broke me from using the stuff.. My Wildman Sport was built with 5-minute and came in ballistic. Nose cone scuffed up but unharmed otherwise. I have since started using US Composites thick stuff with different fillers depending on the task however.

My L2 bird is a Binder Excel with a 54mm mount. It's flown on a J330 and J295 several times. Unless they sneak fiberglass inside the tube, it's just plain old paper as well. :p
 
My L2 bird is a Binder Excel with a 54mm mount. It's flown on a J330 and J295 several times. Unless they sneak fiberglass inside the tube, it's just plain old paper as well. :p

Mine was a Binder Design Tyrannosaur on a J315R, next flight is probably gonna be on a J401.
 
Progress.

Found an hour today to mask and paint the fins.

Used the same transfer method to figure out where to mask at the end of the fillet

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This is why you respray a base coat - mask leakage mischief managed
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Starting to feel like a real rocket now.

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My haste got the better of me - I didn’t mask all the way down and I got some over spray...

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Decals, clear coat and recovery gear to do now.
 
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Sanded and resprayed on the weekend...

Decals tonight.

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More decals.

I’m REALLY happy with how these have come out.


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And TA-DA!

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I'm not a Portal fan but I can still appreciate the awesomeness of those decals.

What was your decal printing setup (paper and printer types), what did you use to clear-coat, etc.? I'm going to be printing my own decals in an upcoming build and am starting the learning process.
 
Printer: brother colour laser (mfc2140CDN)
Paper: laser decal sheets from https://drdecalmrhyde.com.au/shop/premium-waterslide-decal-paper-for-laser-printers-a4-clear/

Two generous (or more) coats of rustoleum 2x clear - I think I did 3-4 medium coats (not heavy, but not “misted” either. You want a balance between too little (which speckles) and too heavy (which runs)... when you think you’re done, add one more medium coat for good measure.

When cutting: very sharp scissors not scalpels - scalpels leave ends kinked down and makes them not sit flat on the edge (doesn’t matter how sharp)

Corners can fold when laying , so round edges when you can, but never curve inwards - inwards curves lead to edges rolling when laying, so outwards curves only.


When applying: WEAR GLOVES! The decals get fingerprints really easily...

A dollop of wood glue in the water.

Soak them 30secs - too long leads to print liftings - if you’re losing print on the decal when applying you’ve either got too little clear coat or soaked too long.

Curve paper to rocket body curve profile just before water lifting from the water.

Did I mention to wear gloves?

Prewet surface with a water mister, or dab around area with wet gloves fingers before laying decal down.

1/4 squares of very good quality paper towels (I use Viva) never use a dry paper towel. I use it to dry my (gloved!) fingers quickly if the paper isn’t moist.

Once decal is down and in the right place - squeegee with the wettest paper towel you have from center -> out (while you pin the location with a GLOVED finger on the opposite side)

Move from wettest paper towel to less wet ones (but never completely dry) and squeegee progressively. You’ll see in my pic I have a line of used paper towels - keep them in a line from wettest to least wet while you work - makes it easier to progressively squeegee when you know where they are.

Look down: smile!
 
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Closing off the thread - L1 successfully achieved on the weekend:

[video=youtube;492dD2168TY]https://www.youtube.com/watch?v=492dD2168TY[/video]
 
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