Pencil Rockets

[Mike]

I sure you all know what I mean, those rockets that look just like pencils, well I've been looking into building a low power pencil rocket and have been looking at many pictures to try and get ideas on how to do it. Many of the pictures that I have seen don't have fins on them -
For example (from one of Eugene's posts in the events forum)

No. 2 Pencil

As you can see this pencil rocket has no fins, so how do you get somthing with no fins to be stable?

Thanks in advance.

 

[Martin Vrstal]

mike...look again..looks like it has small clear plastic fins

 

[Mike]

That might explain it.

Since this is low power and that rocket is high power I don't want to be using really thick plastic. Would transparent vacu forming plastic be sufficent for up to C power launches or will I get fin flutter or somthing?

Thanks

 

[Brian Barney]

I know one way to find out if it'l work

If you or a friend of yours does alot of CD burning on the computer (for backing up files or something......) Alot of the big spindle CDR's come with 2 clear CD's that aren't burnable, but act as a scratch protective cover for the spool on either end. They look lik 1/16" thick clear polycarbonate. They should be more than enough for fin material. Be careful when cutting these though, they are pretty brittle, so a saw without ultra fine teeth would probably crack it. Also, put them away from the base of the rocket, the motor could toast these some making them non clear.

Good luck though, sounds fun...... Maybee if Apogee re-releases their 10.5mm motors you could do a full scale #2 pencil

 

[rstaff3]

A full scale pencil...sounds like a job for Micro-Maxx! BiC pen rockets fly great, and a pencil should also.

 

[Mike]

Me still being at school means I have access to the Technology Department, they have loads of stuff so I'll ask one of the teachers if I could have some clear plastic.

 

[Mike]

If you look at the top of a pencil you can see that the line of paint is wavy, where there is paint, it is flat and where you can see the wood is the rounded bit the pencil sharpener has cut.

Does anyone have any ideas how I could make this with a balsa nosecone?

 

[rstaff3]

Let's see. What would be easiest would be to turn a cone whose lower portion is the same OD as the tube. You could then just mask and paint those portions to give the rippled effect. If you really wanted the jagged edge to be on the cone, I guess you could create a paper wrap to mask the end of the tube. You'd cut around that and then use the same wrap, on a nose cone as described above, and carefully carve out sections so it matched the tube.

Or you could go to the Ralphco site and order a pencil bank

 

[Mike]

I'm trying to go for realism instead of just building a normal rocket then painting it like a pencil. I'm going to cut six lengths of balsa then stick them onto a length of BT-50 so they make a regular hexagon.

For the nosecone I was thinking of taking a balsa nosecone the right diameter to stretch between two opposite points of the hexagon. Then mark the sides of the hexagon and cut down vertically to give the flat bits.

What do you think?

I know this isn't very clear so I'll draw some diagrams then post them.

 

[rstaff3]

ack...you're right, I didn't fully consider the hex body, duh...Milo...help...please remove my previous post

I think your method sounds good. Similiar concept to my second suggestion, but workable

 

[Mike]

Well here is the diagram but it still might not be too clear so please ask any questions about it.

 

[jflis]

Your drawing is fine! May I suggest that you design it with the center of the point just a LITTLE off-center?

If you do that, then the flat edges that you are going to make will result in elipses that are of slightly different sizes and lengths (up the length of the cone part), making it look more like a *real* pencil...

jim

 

[sandman]

I thought about doing the same thing.

Since I have a lathe I was considering making the hex shapped body and nose cone and turning it after it was painted.

I also think I will make my nose cone out of cedar (just to get the right smell!)

I was thinking of a BT-60 size and using a 24mm motor mount.

sandman

 

[jflis]

ok, ok, ok.... here's the *next* challenge....

Do a whole set of *color* pencils that you store in a large (scaled up) pencil box...

now *that* would be kewl *S*

 

[KermieD]

Originally posted by jflis
ok, ok, ok.... here's the *next* challenge....

Do a whole set of *color* pencils that you store in a large (scaled up) pencil box...

now *that* would be kewl *S*

Ooo...Oooo! And, as long as we're doing that, let's make the ferrules out of flippi-fins and launch the pencils right out of the box!

 

[dasein668]

Originally posted by jflis
ok, ok, ok.... here's the *next* challenge....

Do a whole set of *color* pencils that you store in a large (scaled up) pencil box...

now *that* would be kewl *S*

Check out John Coker's crayon pack. Its not finished (at least on the site) but the idea is the same. Very cool concept.

https://www.jcsw.com/john/rocketry/crayons.html

-Nathan

 

[jflis]

beauty! I've done the crayola rocket for years. Am hoping to get it as a kit for FlisKits (negotiating licencing rignt now)

Here are some pix of mine (two different sizes)

mini (BT-5):
https://jflis.com/hobbies/rocketry/photos/mini-collection.jpg

Standard (BT-60):
https://jflis.com/hobbies/rocketry/grand_rocket/images/P5190010.jpg

Another shot of the standard size along with my maxi-mars snooper, mini-starlight, mini saucer, mini gyroc, maxi-birdie, and others
https://jflis.com/hobbies/rocketry/grand_rocket/images/P5190004.jpg

 

[Mike]

Just a little update for you,

I'm waiting for the nosecone I want to come into stock at Apollo 11, much as I would love to turn my own I don't have the facilities so I'm going to buy one (well acctually two because I'm bound to make a mistake on the first )

I have been practicing putting the balsa on the tube ecspecially since I found the can of wood filler, it makes thing so much easier.

 

[Mike]

Just a little update for you,

I'm waiting for the nosecone I want to come into stock at Apollo 11, much as I would love to turn my own I don't have the facilities so I'm going to buy one (well acctually two because I'm bound to make a mistake on the first )

I have been practicing putting the balsa on the tube ecspecially since I found the can of wood filler, it makes thing so much easier.

 

[Mike]

Whoops, do you ever get a feeling of déjá vu?

 

[sandman]

Mike,

you could make the nose cone out of a block of wood and just carve it with a sharp knife...

I've sharpened a lot of pencils with a knife when i couldn't find a pencil sharpener.

It would look "scale'!

sandman

 

[jflis]

oh! that's a great idea (whittleing it down)!

That could also open up another idea for a weird but related scale rocket... do another pencil, but pattern it after those flat (wide) pencils you see carpenters using.

If you design it right, i'm convinced you could make it glide recovery (being so wide and squat in profile)

 

[Jase]

Just for information, the picture of the guy with the big pencil rocket flies at Whitakers. The hexagonal body tube he made using posterboard and very thin dowel rods.

He glued the dowel rods (1/16" I think) to the BT and then layered on the posterboard.

Might be much lighter than balsa.

We got a good look at the construction of one he did that had a motor CATO that exposed some of the techniques of building it.

Jason

 

[Milo]

I thought that ditch and those launch pads looked familiar. That's some creative construction.

 

[Mike]

Yep, I got that pictures from one of Eugene's post about July Whitakers.

I'll look into using the dowel and posterboard techniques.

Thanks

 

[sandman]

Mike,

The more I think about it the more I like the idea of sharpening your pencil with just a knife for a really cool effect..

Before you do that, remember what it's like when you sharpen a pencil with a knife. You tend to hit a little more resistance when you hit the lead with your whittling knife and get a gouged rough pencil point.

Make the body tube hexogonal shapped. Then carfeully make a hexogonal nose cone out of a block of wood to match the body tube.

Then paint the whole thing nose cone and all bright yellow.

Then before you carve the nose cone to the "sharpened" condition, glue a hardwood dowel the size of a scale pencil "lead".

When you go to sharpen your pencil with a knife you will hit the wood dowel (careful don't cut yourself) and get the gouged and mishapen lead effect of a whittled pencil.

Lastly, paint the hardwood dowel flat black.

This sounds like fun!

sandman

 

[Mike]

Alright I'll do it, you convinced me sandman.

Could you please go through the bit about making the nosecone and gluing (sp?) the dowel to the nosecone. I'm a bit new to nosecone shaping.

Thanks

 

[sandman]

OK here goes.

Get a big enough balsa block.

You can carefully carve a sholder part to go into the body tube or just get lazy and glue a body tube couple onto the end of the block for the part that goes into the BT. Don't forget a screw eye for the shock cord.

Make the body tube first with whatever method you decide for the hexogon.

Carfully mark the coupler balsa assembly with the hexogon shape on the end of the block with the coupler/sholder. Use a fine tipped felt pen 'cause a pencil won't make much of a mark on end grain balsa.

Cut it down a bit with a razor knife. (a boxcutter knife with the retractable blade would work good) Not too much...by roughing out the Hexogon shape.
Be careful with this part 'cause the balsa grain will direct the cut and you could mess up here very easy!

Finish the final shape with a nice flat sanding block and match up the six sides of the nose cone with the sides of the body tube.

Depending on the final size of the pencil use an appropriate (pencil lead) size wooden dowelglued down the center of the nose block. Like a 1/8" dowel for a BT-50 or BT-55 and a 1/4" for a BT-60. Make sure it is long enough!

Paint the whole assembly bright yellow.

Now with your boxcutter knife, sharpen your pencil. Leave enough of the wood dowel sticking out but not to a point. Maybe rub the tip on a piece of sandpaper to simulate a worn tip.

No sanding of the outer wood part...you want it to look hand sharpend!

Now carefully paint the dowel (the lead) flat black.

Now you will have to do the back end with a motor mount and clear fins and an eraser (worn down of course!) and the brass ferrul.

Go have fun.

sandman

 

[Mike]

Thanks again Sandman,

Would I make the eraser section out of another piece of balsa?
How would I do the ferrul bit?

 

[sandman]

Mike,

You could but I think just the appropriate color paint would be enough for an eraser.

Now for the ferrul maybe tin or brass foil embosed with a pattern wheel or something.

sandman