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[user 45779]

This build thread will be my entry for the TRF Challenge #1: Estes Menace.
I will post all the files (stl, svg, ork, etc.) once the build is complete.
If all goes well, our next launch event is on 3/9, so might get a flight on record before the 3/15 deadline.

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Super Menace Parts List
-----------------------------------
(1) NC-80B Nose Cone
(1) 23.5" BT-80 Body Tube
(2) 3/16" X 1" Launch Lugs
(1) 6" X 12" x 1/8" Balsa Sheet
(1) Intake Scoop (3D Printed)

(3) CR5080 Centering Rings
(1) 8" BTH-50 Engine Mount Tube
(1) CR2050 Engine Block Ring
(1) 24mm Threaded Motor Retainer (3D Printed)

(1) 18" or 24" Parachute
(1) 24" 250# Kevlar Cord
(1) 1/4" X 48" Elastic Shock Cord
(1) #4 Ball Bearing Fishing Swivel

 

[user 45779]

Engine Mount Assembly

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1) Glued the CR5080 rings (with nice fillets both sides) to the BTH-50 Engine Mount Tube at 1/2", 3-3/4", and 7-7/8" from the bottom end.

2) The BTH-50 is foil lined, so mixed up small batch of epoxy and set CR2050 Engine Block using my 3D printed engine dummy.
The engine dummy has 2 grooves. The groove closest to one end is where 5/16" from end of an E engine and the upper groove for D engine if so chosen to not make E capable. Then the dummy can be snapped apart at the grooves to leave a D to E engine spacer. Also used the epoxy to glue on the 24mm Threaded Motor Retainer.

3) Cut a small hole in the upper CR5080 ring for the Kevlar cord to tie around the engine mount, then wrapped it up and stuffed in side the tube to keep out of the way.

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[user 45779]

Cutting Fin Slots in Body Tube

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I considered making a 3 fin variant, but decided to go with the original 4 design. However, I designed a paper fin marking template, that has both 3 and 4 fin layouts, and also a 3D printed a version. The rear fin slots are 7/16" to 2-1/4", and the wing slots are 6-3/8" to 7-7/8", from the bottom. Using a fresh knife blade, cut the slots, then made sure the top CR5080 ring lines up with the top of the wing slot, and the bottom CR5080 ring lines up with bottom of the fin slots.

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[user 45779]

Preparing the Fins

To make the fins, I used Inkscape to trace the images from Jimz site and create an svg to use with my laser cutter and the 6" X 12" x 1/8" balsa sheet (10W diode laser, 300mm/min @ 50% power, 1 pass).

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I also have started papering fins using permanent adhesive Avery label paper, so also used the laser to cut those. 1800mm/min @ 50% power cuts just through the paper but not the backing.

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After lightly sanding edges and surfaces, I use an extreme sticky lint roller to remove the dust from the surfaces and apply the papering.

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I round the leading edges after papering, the use CA to strengthen and seal the edges (except the root edge). Then let the CA cure and sand the edges very lightly with a very fine sandpaper.

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[ljwilley]

Nice job so far! Excited to see the end result!

 

[user 45779]

Attaching the Fins

Applied glue to root edges, rear facing edge of the fins, front facing edge of the wings, and used a 3D printed alignment jig to hold in position.

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[user 45779]

Lugs and Intake Scoop

I like to use Quick & Thick for the final fillets and tuck the launch lugs up against a fin for extra bonding surface.

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I made just a few prototypes before settling on which 3D printed intake scoop design.

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The one I went with is printed flat .6mm thick (3 layers @ .2mm), with edges beveled to match tube, and grooves .2mm deep to "fold" the plastic, and weighs about 7g.

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After folding the plastic, I went ahead and papered it and left about 1/8" overhang along the edges that meet the tube, then used Quick & Thick on the beveled edges to attach to the tube.

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[ljwilley]

Looks amazing! Very good idea to do the intake thin and light, makes for less corkscrew/ bad weight distribution. I like cool upscale threads!

 

[user 45779]

Took a bit of sanding to get the mold marks out of the nose cone, then put on a coat of flat white primer in case we get to fly Saturday, but the weather forecast is not looking good.

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Also, 3D printed a threaded motor retainer cap with "nozzle" probably for display only since it is kind of heavy (10g).

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[ljwilley]

I really like the nozzle you made for it. The menace is by no means a "high performance" rocket, so I would not be so worried about weight. I do not think that 10 grams would be enough to make you decide not to fly it with the nozzle. I would fly it. Whatever you decide, the rocket is still very, very cool and that is all that matters!

 

[user 45779]

Launch was scrubbed yesterday, but gave me a chance to go ahead and sand it down and put a nice coat of gloss white on.

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Ready for decals!

 

[user 45779]

Recovery

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I wanted to use a 24" parachute for this bird and the ones I have on hand are the "self assemble" kind, which turned out to be one of the more challenging parts of this build....tying 8 tiny bowline knots with shaky hands and bad eyes. Evened up the lines and tied them in a loop about a inch from the end, then put the loop thru the eye of the bearing swivel.

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I pull the Kevlar cord thru the body tube and thread a foam ear plug on for protection, then tie to the elastic shock cord using a "double-uni" type knot for those fishermen out there.

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I tie the elastic shock cord to the nose cone and then clip the bearing swivel and it's ready to be packed.

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[user 45779]

Decals

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Ack I'm naked!

I used the svg provided by @Aeva in the TRF Challenge thread as a base, scaled, added a few more, and laser printed on clear peel-n-stick decal paper. Then got out the exacto knife...

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30+ decals later....

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I will probably put a clear coat on tomorrow, and that basically finishes my build.
Our launch last Saturday was scrubbed due to weather, but might be re-scheduled for this Saturday 3/16.
I will post all files (stl, svg, pdf, etc) tomorrow morning.

 

[user 45779]

As promised, attached are all the files I used in this build for 3D printing, laser cutting, and decal printing.

It was my first time using OpenRocket, so I just used a "tube-fin" to simulate the scoop and overrode the weight to 7g...and K'Tesh already crushed the ork.

Also, here are links to my tinks:

Retainers:
https://www.tinkercad.com/things/gS...e=pWTrejvPSPopqs80bTMATdkB6kOLBPBauNlawSPtKt8

Intake Scoop:
https://www.tinkercad.com/things/1A...e=x7cODSDt2hWhClf6W2afQEvWgZ0vWeBBGVDKPmUYmJQ

Fins, Rings, Engine Dummy, Tube Slot Jig
https://www.tinkercad.com/things/55...e=Xy3SEap6F98pjn1iISlHMqsKjcpGamxoW2OMruTDruI

It weighs 267g with an E12-6 loaded, which is 25g more than the sim says. :/

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Hoping to get to fly tomorrow!

 

[ljwilley]

Delete?

 

[ljwilley]

What happened!

 

[tim cubbedge]

he’s angry

 

[cwbullet]

If you have deleted your posts, I cannot judge your project for the contest.