'cigar' shaped rocket - how??

[stevem]

Hi Guys,
I need some help - my son and I want to build a Duck Dodgers spaceship like the one in the new DD series on cartoon network.
My question is what methods are there for creating an airframe with a nice cigar shape. Shrouds won't work because I want a nice smooth curvature of the airframe. Is there a way to do this?
maybe out of styrofoam? any ideas?
thanks!
Steve

 

[wwattles]

You can always revert to the tried and true method that our brethren in the model airplane business use: ribs and stringers, with a coating stretched over them.

WW

 

[Manwithbeers]

A friend has been working on a similar project. Taking the methods used for hot wire cutting the core of a foam nose cone he is cutting airframe sections and then coring them to install an internal 38mm motor tube and payload bay for chute etc. Fins are installed onto the full length motor tube. Outside surface will be coated with fiberglass.

High impulse motors do run the risk of de-laminating damage. Possibly a shed as someone else has reported. Finishing is a high priority I think.

Just confirming your idea...

 

[stevem]

now that's an interesting idea.
Have you ever actually done this?

 

[stevem]

ww - my last post was meant for you

Manwith beers (love that handle!) - that may be the answer - how does one go about 'coring' out the foam body? I was thinking I would have to core it out and epoxy in a BT but so far I haven't figured out how to do that.

 

[stevem]

oh man I think I understand now - you mean your friend is building this up in layers and coring out each piece as he glues the layers togther? the light is slowing coming on...

 

[wwattles]

SteveM,

I've done it a few times several years back, twice with powered model planes, and once with a 7-foot wingspan glider. You'll end up with a slightly faceted surface, but it's supported and fairly close to round. It'll look a lot like those old WW I planes that had ribs & stringers with cloth between them.

As for construction, I wouldn't plan to put much more than a D or E motor in it because the surface of the rocket would be too stressed to take the pressures. There's a reason people stopped building planes that way when they started getting more power...

WW

 

[Manwithbeers]

I've made nose cones and I'm planning a similar idea. My friend manwithoutbeers has finished most of the body of his retro rocket. He's cored out 4 of 5 sections. Each section is about 12 inches long. Yea, cut up the cigar then core it with the hot wire. the slit from the outside surface to the core dsoesn't matter because it's all being covered later. The light is indeed glowing eh?

 

[stevem]

yep - the light now has a steady glow!
now I have another concern - how come manwithbeers has a friend without beers!? buy him some beer for heaven's sake!

 

[rbeckey]

The easiest way I know of to make a cigar shaped rocket would be to use a short BT and two NC. See This thread:

https://www.rocketryforum.com/showthread.php?s=&threadid=3446

One NC becomes a tail cone by cutting the point off far enough back to fit in a motor mount. You could assure a square cut by fitting the NC into a section of tube and cutting it on a miter saw.

 

[OKTurbo]

Another option would be paper mache'. I've haven't tried it yet, but with enough of a supporting structure it ~should~ work.

John

 

[powderburner]

Foam may be one way to go, but don't overlook balsa. You could build up a block (with hollow core on a temporary spindle, or with solid core and drill it out later) and turn it on a lathe or home-made device (electric drill) with much better control of the surface shape and finish (IMHO). And when the motor fires and gets hot, the balsa won't get soft and gooey. The surface of the balsa can be toughened with thin epoxy, and yes, I just don't like to carve foam.

 

[cls]

great topic!

I built a Duck Dodgers "classic" from two PNC60-AH and a short piece of BT60.

trying to figure out the fins was real trouble because - in case you didn't notice - the ship changes a bit in every scene!!! try going through the cartoon frame by frame some time.

anyways it isn't flight-stable with that big rooster comb fin up on top in front and just two fins in back, so I had to make some compromises. the question is, is it recognisable?

... no idea what the ship in the new cartoon looks like.


for making odd or large shapes that need to be light weight to fly... I've had good results making frames out of balsa strips and covering with bristol board. I used CA to put the strips together and yellow glue to put the bristol board on.

I used bristol board 'cos it was recommended by TVM but I think 100# stock paper would work. and 100# will run through your color printer which will save you a bunch of effort finishing the rocket.

 

[Hexnut]

We have done foam cutting with a home made "Foam Bow" for nose cones but it would work for what you are thinking. Check out this page on our site. It is does not have a whole lot of info but you can see the bow and the fixtureing we use. I plan on adding to the site on foaming but time has been tight.

https://www.trailertrashaerospace.com/foam_cutting_page.htm

 

[wyldbill]

Check out The Rocket Formerly Know As Black, it's a beautiful example of glass over foam, as is its brother, The Happy Birthday Party Napkin Rocket of the Apocalypse . You may be able to scale these techniques down...

-bill

 

[Manwithbeers]

Fantastic! Great link for my Favorites. Thank you for posting that.

 

[powderburner]

Maybe use a shell that is pre-painted, fill it with expanding foam?

https://www.thundertube.com/newindex.html

 

[Elbmod]

Have you seen the vatsaas brothers site - they've done a couple like this - The Rocket Formerly Known As Black (TRFKAB) and the HAPPY BIRTHDAY PARTY NAPKIN ROCKET OF THE APOCALYPSE

https://www.vatsaas.org/rtv/arsenal/bradrocs/black/black.aspx
https://www.vatsaas.org/rtv/arsenal/bradrocs/napkin/napkinrocket.aspx

John Coker did a similar shape in a different way for a buck rodgers rocket

https://www.jcrocket.com/flashgordon.shtml

 

[wyldbill]

Originally posted by elbmod
The Rocket Formerly Known As Black (TRFKAB) and the HAPPY BIRTHDAY PARTY NAPKIN ROCKET OF THE APOCALYPSE

As noted in the post three above yours...

 

[stevem]

wow - thanks very much guys - this has been lots of help.
the web site with the black rocket is great!
I think I'm going to give the foam a try.
where can one find a foam cutter or plans to build one?

 

[stevem]

heres a pic of the NEW Duck Dodgers rocket...


also - powderburner - I'd overlooked your post. I may try the balsa first, I just got in some good size balsa lumber from BMS.

 

[stevem]

oh man I just found the info on making a hot-wire foam cutter here

I'm going to pick up some foam this evening - will the 'blue board' type of faom insulation work or do I need the regular white styrofoam stuff?

 

[powderburner]

Either type will cut with a hot wire setup, and as far as I know, both types will produce dangerous (poisonous) fumes. Work outdoors if you can, or in the garage, or rig something with a big fan sucking the room air out the door.

We want you to be around long enough to report on your project after it is finished.

 

[DavRedf]

I hav'nt tried this on anything as big as a rocket but it worked for drop tanks on a scale model aircraft.

Carve or mould the shape you want out of what ever, I used balsa and turned it to shape, cover in soap/oil to stop sticking and the wind sticky paper tape over it until you get the thickness you want. Let set, give a coat or two of varnish. Let dry then cut around the centre and remove the core. When all else is done a coupler can be used to hold it together.

David

 

[Ray Dunakin]

Originally posted by stevem
Hi Guys,
I need some help - my son and I want to build a Duck Dodgers spaceship like the one in the new DD series on cartoon network.

Cool! I've been thinking about making a high power model of that spaceship ever since I first saw it -- maybe even a kit! I love the way it looks and think it would make a great fiberglass kit. But I'd probably make a few modifications to avoid copyright problems.

 

[stevem]

Still working on our Duck Dodgers rocket - After reviewing all the options presented here I decided to go with the Vatsaas

The first picture is of the foam cutting tool I made. I found that a guitar string of .018 and a transformer setting of about 12volts produces the best cut with my setup.

The second picture shows the cutting jig and the roughly cut airframe.

so far this has been a lot of fun - I think the most enjoyable part is perusing the Vatsaas web site. These guys are amazing to me. I love thier sense of humor.

Next step will be to build a stand to rotate the airframe while I glass/epoxy it.

 

[stevem]

secnd pic...

 

[stevem]

made some progress on my first cigar-shaped rocket, AKA Duck Dodgers spaceship.

I am real pleased with how this is turning out. My apologies for the less than quality pictures.

The rocket will be 35" long and approx weight should come out just under 2lbs. (hopefully). I am trying to keep the rear as light as possible. The engine pods on the ends of the wings were turned using my drill/lathe. I used a cardboard template to make sure they were each identical and then I hollowed out the inside of them with a drill and a dremel.

This first pic is a shot of the major assemblies.

 

[stevem]

next pic shows everything dry fitted together.
tonight I'll finish priming/sanding and start glueing things together.

 

[cls]

Steve - awesome!! thanks for posting pix, very inspiring!! Can't wait to see it painted. and flying!

Cliff