A rocket for a smurf

[heada]

Such a waste of smurf-berry pie!

 

[Funkworks]

But what about the pie attack on the cat?

I dunno, isn't that what real cartoons do? A moment of suspense, and then commercials until "next week" or so? Well, at least I don't have commercials! (unless I guess I'm promoting smurfs and tools, but it's not like anyone's paying me for it, it's just my stuff and part of this crazy hobby combination I got myself into).

George Lucas said SFX are nothing without a story, so like his movies, the story here is basically just an excuse to show off cool stuff like a catapult and pies (which I guess aren't really special effects, but the most special effecty stuff my budget allows) So enjoy the special SFX! Enjoy the catapult! It took 6 months and a pandemic for it to be built!

Also, posting story stuff without progress on the rocket is beyond what the forum is for. So each post has to show progress on the rocket itself. That's like a constraint I use. Trying to keep a balance.

Anyway, after I posted that last picture, I realized I hadn't finished removing wood in the cone, so here's the finished nose cone!

 

[Funkworks]

Handy:

We tried to make a door hinge out of a piano wire passing through 2 pairs of eye screws, but it turned out to be too rigid! To keep it from sliding out the top, we had to make a loop on the top end of the wire, around the upper eye screw hinge, but the steel it’s made of is so stiff even Hefty Smurf couldn’t close the loop using my best tools in the limited space of the crew cabin! So we found a cheap hanger instead. Hanger steel is much easier to work with!

Here I am with the piano wire we tested. On the top right of the picture, you can see the eye screw hinge we couldn’t bend the piano wire around:


And here’s a close-up of the upper eye screw hinge, half in the shadow. You can see the hanger wire bent around the pair of eye screws. Now the door can open and close, but the wire won’t slide out when the ejection charge goes off!



(Back near HQ)

Hefty:
When Azrael saw us, he dove back in the forest Papa Smurf! We waited all day but he never showed up again!

Papa Smurf:
He probably remembered the last time we jammed his face with a load of smurfberry pies!

Greedy:
Azrael sure missed out on a HICCUP! … tasty treat!


Brainy:
The FOREST!?! But that’s where Astro is training survival skills!

Smurfette:
OH NO! What if Azrael finds him!?!

Grouchy:
I HATE that Astro and Azrael are both in the Forest!

 

[Funkworks]

Astro:
They say I have to practice surviving in the woods in case my rocket ship doesn’t reach the stars and I fall back to Earth! So here I am! Deep in the Forest! To keep busy, Clockwork 2 and I dug a well!

Clockwork 2:
Bort Tweek Rattle Rattle Gwink Zert Bonk!

But the plan is that once in outer space, we’ll find an alien resort with all amenities included! Nice weather, sandy beaches, clear starry skies and … NO CATS!

Cats are the worst! They really are! They’re a threat to all smurfkind and I think we shouldn’t even be on the same planet at all!

STUPID CATS! There! I said it!



Handy:
Look what Tailor Smurf did! He put together a 45” parachute and a black Nomex protector, and tied 3 Kevlar loops to a center to keep the fins attached to the airframe when they slip away during ejection! Astro had done this with polyester and hemp cords, but Kevlar is better! What are you sewing now Tailor?

Tailor:
This here is just an old sock Handy, but if I make a hole in it, Brainy says it can tell us in which direction the wind is blowing!

 

[Funkworks]

ZWEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE………………….!!!!

.......EEEEEEEEYAAAAAYYYYYYYYYYYYYYYYYYYYYYYYY.....!!!!

………….. YYYOOOOOOOOOOOOOOOOOOOOOOOOOOOUUUUUU!!!!

Astro:
WHAT was THAT?!?
A strange flash of light!?!
Maybe it was a falling star!

When a star falls, it can make a strange flash of light!
Come on Clockwork! Let’s go smurf for it!

Clockwork:
Tweedle Tweedle Flop Doing!

Azrael :
… ZZZZZ … ZZZZZ … ZZZZZ…


Handy:
Astro’s crew cabin needs a ceiling for 2 reasons:

1. To prevent ejection smoke from soiling Astro and choking him.
2. To prevent Astro from falling out if his seatbelt fails.

So the crew cabin needs a ceiling, but the ceiling needs to open outwards like a hatch, so we can lower in and remove the fake floor with the pilot seat.

But for hinges to work, we need to cut off that part of the motor tube right above my right ear that overreaches the middle wall, because that wall needs to support hinges, and hinges will only allow a ceiling-hatch to open if there’s no superfluous motor tube in the way.

So to cut off the top part of the motor tube, we used a rotary tool with a cut off disk!

First, we stuffed some paper towel in the cabin to prevent saw dust from messing up the cockpit:

Then, we cut away with a bit like this:

Ready for the hinges and ceiling-hatch!

 

[Funkworks]

Handy:
For the ceiling/hatch, we sanded a leftover half-donut-disk to make sure it fit inside the crew cabin and got these smurfy hinges.

We fitted everything manually to mark where the screws should be on the ceiling/hatch:

And we screwed the hinges in place:

On the backside, which is what the pilot sees, we chopped off the screw tips, and pressed pieces of balsa on the remaining tips with epoxy. Soft as a cushion!

Next, we install this on the airframe!


K9:
Sniff, sniff, sniff …

Marvin:
Oh, goody goody! What a strange Earthling you have located there K9! Hmmm? You must be so glad you finally got to use your new insomnium Q-One-Zero sleeperator! HMMM!

This funny-looking creature will make such a lovely 2-state Qubit upgrade for our quantum computer back on Mars! I just can’t wait to calculate the success probability of my new peanut-butter-pumpkin cupcake recipe!

Oh! And look! It appears that the fuzzy beast has built itself a primitive ground water extraction apparatus. How very interesting! A much more intelligent species than one would expect from this planet. HMMM! Let us go back to Mars now with our catch.

 

[Funkworks]

Mechanic:
Handy and I finally installed the hinged ceiling!

At 10:30 and 4:30 in the picture, you can see the brass hinges and the two screw-tip covers made of rectangular balsa boards we painted red.

At 5:00, you can see a welding steel rod we found that fit perfectly as an axle for the door hinges made of two pairs of 7/16” eye screws.

At 6:30, you can see another pair of eye screws. Each one is epoxied in place so they be held together with a jewelry lobster clasp to make a door lock, or, if we want to lock Astro up more safely, we can slide another steel rod going from the floor to the ceiling!

At 6:00, we’re clamping an unpainted second board above the door. This board is just the right height to hold a piece of Velcro to keep the ceiling shut! The shut ceiling will also keep the one or two door rods in place during flight! Once the glue has dried and the Velcro pieces have been applied, the top part of the rocket will be done!



Astro:
We’ll never find that fallen star Clockwork! We’ve been looking for smurfs and smurfs now!

Clockwork 2.0:
Tweedle Tweedle Flop Dong Garble Garble Doink!

Astro:
And the sun’s too warm! Quick! Run get my smurf so I can get out here before I start cooking!

Clockwork 2.0:
Razzle Dazzle Dingle Tron! Dingle Dingle Woosh!!

 

[Funkworks]

Clumsy:
Great news Handy! I finally found a magnet to hold the door shut Handy!

Handy:
Gee Clumsy thanks… But we found a pair of tiny eye screws for that. They weigh less than a feather! Look! We just painted the final coating on the rocket! It took care of the door frame, the fin seats, and a few dings that came up while working on it.

Vanity:
Nice! Very very nice!

 

[Funkworks]

Astro:
You brought back my smurfer!

Clockwork:
Tangle Tong Flip Flop Yarny Schlurp Zwang!

Astro:
They need me back at the village to test out a seat belt? ... I’LL RACE YOU!!!

Clockwork:
Tweedle Garble Zooey Clang!

Astro:
I don’t need a head start! WEEEEE!



Carpenter 1:
Astro’s first ladder was too big. But now that the rocket is almost done, we got to make measurements and made it the right length!

Carpenter 2:
And the recovery gear all ready to be fitted inside. We’re just waiting for the shock cord now!



Handy:
To strap Astro on his seat, Blossom used natural undyed hemp cord, so if it rubs on his space suit, it won’t leave a mark!

Blossom:
I used 3 cords, one around the waist, and one over each shoulder.

Brainy:
In aerosmurf engineering, it's called “REDAMUNDANCY”!

Astro:
Beam me up Smurffy!

 

[Funkworks]

Clumsy: Gee Hefty, where are you going dressed up like that?
Hefty: Astro is way too smurfed out to be alone up there so I’ll be smurfing along for the ride!

(shock cord to nose cone)

(shock cord to payload bay)

 

[Funkworks]

Bottom motor mount and motor retainer:

Recovery and Jumper:

Pilot:

What's left?
- Rail guides
- Attaching the ladder, but not critical.

 

[jqavins]

Is there any sort of latch to keep the ceiling over the pilot's compartment?

 

[tsmmiller]

Is there any sort of latch to keep the ceiling over the pilot's compartment?

The velcro strip?

 

[jqavins]

Yup, on closer inspection that would be what the white bits are. Shoulda seen that.

 

[Funkworks]

I haven't tried yet, but I might be able to pack the parachute inside the tube. I'll play around with parachute folding and packing to see what can be done.

Unfortunately, the ceiling hinges are positionned to maybe grab on to parachute cords. I probably could have avoided this, but I glued them on weeks ago and only saw it yesterday.

The velcro strip's own glue isn't very reliable in that sometimes, they "un-glue" instead of "un-velcro". So I might epoxy each strip in its place.

I'll probably take a ton of good photos showing the "features" soon. My feeling is that this is going to unexpectedly explode or drop like a rock, so at least I'll have memories. The photo album will be called "How I spent my COVID year" .

 

[jqavins]

If you're concerned about the velcro, there are other ways to go.

1. A very thin strip of sheet metal, fastened with a single screw to the hinged bulkhead to it can swing, and just long enough to go a couple of millimeters into the side wall (where you would cut a slot).
2. Use the gap between the hinged bulkhead and the sidewall accommodate a piece of springy, thin sheet metal, thin spring steel, beryllium copper, or similar. Its relaxed position has it extending over the bulkhead, but it can be pushed against the sidewall to let the bulkhead pass.
3. Other creative solutions.

Number 1 is probably easier, but I like number 2.


As for the hinges snagging the shroud lines, I advise some work with a needle file followed by an emery board to round over the corners and edges so that, even if the lines contact the hinges, they just slide right past. (In hindsight, doing that and polishing them before installation would have been good. Do you think it you remove the screws you might be able to crack them loose from the glue without damaging anything?)

 

[Funkworks]

In hindsight, I should have screwed the hinges on the pilot side, and have the axles on top of the wall, instead of over the bay. But with the wall already glued in place, I had no way to work a screwdriver, so I epoxied the hinges on a random side of the wall, without realizing where the axles would end up.

By balancing, I just found that the CG is right above the doorstep, which I think is great. That’s at least 2 inches ahead of the fins so definitely ahead of the CP.

While balancing, the nose cone accidentally fell off partly (no damage) and just enough to pull out the smurf and half the parachute. It was a pretty good confirmation that deployment would work as it should.

I epoxied the Velcro strips before reading this but your solution 2. seems perfect. Had I thought of that I probably would have done it. I’ll probably stick with Velcro for now though. I had it at hand so it was the easy way. The only force on the ceiling will be the ejection event and that will just press it down so I’m not worried.

Can’t help but think about ways to keep the ladder against the airframe. Wondering if I can make a bracket to match the comic-cartoon. I think I can make one with wood and glue (4 of them), painted metallic. I guess I’ll do that next.

 

[jqavins]

In hindsight, I should have screwed the hinges on the pilot side, and have the axles on top of the wall, instead of over the bay. But with the wall already glued in place, I had no way to work a screwdriver, so I epoxied the hinges on a random side of the wall, without realizing where the axles would end up.

Reaching in with a file to round things over would be challenging, but IMHO worth it. It may even be worth sacrificing a needle file by snapping off a short piece so that it can get around better.

 

[Funkworks]

Reaching in with a file to round things over would be challenging, but IMHO worth it. It may even be worth sacrificing a needle file by snapping off a short piece so that it can get around better.

Yes that I can do. Good idea. And I have just the files for it. They've been patiently waiting in my glue box for over a year. I always forget I have a kit of small files because they were stored in the wrong box, but I'll get that sorted out shortly.

 

[Funkworks]

Oh darn! (I use "darn" as an expression of joy these days, go figure) I just thought of how to make the ladder bracket.

3 parts :
- flat, rectangular piece of wood as the base plate against the surface, but just for looks.
- a square post from the plate to the ladder, but just for looks.
- two wooden bagel halves to wrap the ladder post.

And a 4th part, only structural: a metal wire, planted and glued in the rocket at one end, and in the ladder at the other end, but complety hidden by running through the wooden parts.

 

[Funkworks]

Found that set of tiny files that were misplaced.

Chopped and sanded 4 backing plates for the false ladder brackets.

Sawed off, drilled and “Dremelled” 4 rings for the false ladder brackets.

Drilled 4 holes in the ladder to insert metal wire (straightened paperclips) to actually hold the ladder against the rocket permanently (will be shortened and glued at each end to rocket and ladder).

 

[Funkworks]

Rolled up some oven-bake clay around paperclips to simulate the middle part (arm?). Paperclips are rubber-coated. That might help with epoxy.



Four of them:


15 minutes at 125C had its effect but it will all be painted or hidden so no worries. Here’s the approximate positioning of the parts.

Here’s the best reference I have for what these 4 brackets should look like:

Next up: painting these twelve parts with a brush.

 

[Funkworks]

Turns out I’m better off gluing the brackets together, then painting them, then chopping up the ladder, then gluing back the ladder again, but in the brackets.

Sometimes you don’t really know until you get there.

 

[Funkworks]

- Finished the 4 brackets to hold up the ladder.
- Painted them with Testor's "Flat Steel".
- Sawed off and painted at least 12 slices from a 3/16" dowel. Six of them will be for the bolt heads seen on the rocket's door, and 2 of them will be on the top edge of each fin.
- Also painted the dowel slices with "Flat Steel" to make them bolt heads.


The ladder, 4 brackets, 6 door bolts, and 2 fin bolts per fin can all be seen in this drawing:

 

[Funkworks]

Mechanic Smurf:
I picked those false bolt heads that looked the most like real ones, and Blossom glued them on with carpenter's glue!

We'll have to check with Handy, Astro and Papa, but I think fastening a rail guide is all that's left to be done!

 

[Funkworks]

Sassette was growing impatient with the slow progress lately so she got a timer to get them working again. Carpenter got the ball rolling by sawing off the ladder endings so it could be inserted in the brackets.

Making sure everything stays nice and tight while the wood glue dries:

Drag be smurfed!

 

[BABAR]

this has been a cool thread and I hope you get a great flight.

if not, then, “Oh the Bluemanity!”

 

[Funkworks]

I would prefer a motor that doesn't explode but aside from that I'm pretty much open to any kind of flight and landing. Scratches will only add character. My main concern is weight. It's ending up being more suited for a 38 mm than a 29 mm, but I'm not yet L1 and probably won't be for a while. I'll weigh it again when it has a motor and rail guide before deciding how and when to launch it.

 

[jqavins]

CTI or AT? CTI has a 29 mm 2 grain Vmax, G250, and a White Thunder G126 also in the 2 grain case. Aerotech has the single use G125 and the G138 reload for the RMS-29/40-120 case, both Blue Thunder. Any of those should get you plenty of rail exit speed for a safe flight if your weight isn't huge, and the G250 should even if it is.

Of course, you'll probably want the minimum ejection delay, whatever motor you pick, this rocket being so very draggy.

 

[Antares JS]

CTI or AT? CTI has a 29 mm 2 grain Vmax, G250, and a White Thunder G126 also in the 2 grain case. Aerotech has the single use G125 and the G138 reload for the RMS-29/40-120 case, both Blue Thunder. Any of those should get you plenty of rail exit speed for a safe flight if your weight isn't huge, and the G250 should even if it is.

Of course, you'll probably want the minimum ejection delay, whatever motor you pick, this rocket being so very draggy.
View attachment 473980

You still have to have a level 1 cert to use a motor with greater than 80 N average thrust, even if it's a G or F.