The Washington monument as a rocket?

[Senior Space Cadet]

I was thinking it might be interesting to make a rocket that looks like the Washington monument. I'd make it out of sheet balsa or birch.
Anyone know of anyone that's done it before?
https://www.bing.com/images/search?...&form=IRTRRL&first=1&scenario=ImageBasicHover

 

[Nytrunner]

Specifically the Washington monument? I haven't read of one. Should be an interesting build, slightly tapered square tube with a pyramidal nosecone. Some clear plastic fins on the base for stability of course.

New Way rockets makes square rocket kits, and has square rocket body tubes also. May be able to get some parts or inspiration from there

 

[Senior Space Cadet]

Specifically the Washington monument? I haven't read of one. Should be an interesting build, slightly tapered square tube with a pyramidal nosecone. Some clear plastic fins on the base for stability of course.

New Way rockets makes square rocket kits, and has square rocket body tubes also. May be able to get some parts or inspiration from there

The Washington Monument is, of course, and Egyptian obelisk. I don't suppose it has to be the Washington Monument.
I'll check out New Way rockets.

 

[dhbarr]

https://en.wikipedia.org/wiki/Lateran_Obelisk already has a nice base added onto it if you want more scale and less clear fins.

 

[dr wogz]

And, Cleopatra's' Needle can also be an inspiration..

https://en.wikipedia.org/wiki/Cleopatra's_Needle

 

[boatgeek]

It would be very doable to make an obelisk with four each trapezoids and triangles from sheet balsa. If it was my project, I'd get some small square section wood pieces to reinforce the corners and make building easier. An 18mm motor mount and fiber centering rings cut to size would round it out. This would probably be a good application for rear eject.

 

[Senior Space Cadet]

Found this.
https://images.fineartamerica.com/i...ument-engineering-drawing-daniel-hagerman.jpgI like the idea of the square balsa sticks in the corner. I'm going to use birch squares for the centering rings. I'm thinking four 18mm motors. I need to buy either and 18mm or 24mm hole saw.
I want to make this fairly large. I'm thinking four 4" x 36" balsa sheets for the sides and another sheet to make the cap.
Since the cap is a different angle from the sides, making the cap removeable is going to take some work. Might be easier to make the separation farther down. Then I can just put some balsa sheet inside the exterior walls and extending past the top. Or, as boatgeek suggests, maybe a rear eject.
Since the walls are sloped, how to I do the launch lugs? Any ideas?

 

[Nytrunner]

It sounds like you'll need 24mm motors. 4x D-motors could work.
CAUTION: if the sum total of propellant weight (not motor weight, propellant weight) exceeds 125 grams, you are now a high-power rocket and require an FAA waiver to launch. Example: 4x E12s exceed that limit

Separating below the cap is a good plan. You can run the central motor tube all the way up and put a coupler in the cap bulkhead. A locator pin and hole in the Cap and Body bulkheads can keep it straight
Also Rear-eject is a good idea too.

Odd shaped body rockets and saucers/pyramids have an internal launch lug along the motor tube. Pokes out a hole in the top. Heck with a 4xcluster, you could have it right through the middle

 

[mooffle]

For launch lug: a tapered standoff is what I would do.

Instead of fins what about base drag and include a square of green lawn around it.

 

[Joekeyo]

Thrust vector control

 

[MClark]

I have seen an Eiffel Tower.
it was basically as an obelisk with the bars painted on and where the legs flair out being fins.

M

 

[Senior Space Cadet]

It sounds like you'll need 24mm motors. 4x D-motors could work.
CAUTION: if the sum total of propellant weight (not motor weight, propellant weight) exceeds 125 grams, you are now a high-power rocket and require an FAA waiver to launch. Example: 4x E12s exceed that limit

Separating below the cap is a good plan. You can run the central motor tube all the way up and put a coupler in the cap bulkhead. A locator pin and hole in the Cap and Body bulkheads can keep it straight
Also Rear-eject is a good idea too.

Odd shaped body rockets and saucers/pyramids have an internal launch lug along the motor tube. Pokes out a hole in the top. Heck with a 4xcluster, you could have it right through the middle

There are Quest 18mm D16-8 and C12-8 motors that I'm thinking about. The C12s might not send it into the stratosphere, but that might be a good thing.
I was thinking about the rod going right up the middle. But I have a 6' rod (I'm bragging a bit) and I was planning on a meter long obelisk. Using the peak as a guide hole might not work well and getting three holes lined up perfectly would be extremely hard. I might need to downsize.

 

[Senior Space Cadet]

I'm not thrilled with the clear fins idea. The idea behind them is to be invisible, but they never are. I think they might look out of place.
I'm thinking of architectural looking balsa fins. Maybe with a stepped leading edge. Might not be terribly aerodynamic, but light and I think they might look more like they belong on it. I might make both and do a test fitting and see which one looks better.

 

[Senior Space Cadet]

What thickness balsa sheet do you think?
I was thinking 1/8", but that will make a pretty heavy rocket. 3/32" might be enough. I think 1/16" would be too flimsy.

 

[GlenP]

What thickness balsa sheet do you think?
I was thinking 1/8", but that will make a pretty heavy rocket. 3/32" might be enough. I think 1/16" would be too flimsy.

Use the thinner sheet like a skin, and add some internal frame structure, like stringers and ribs for strength, see how a balsa model airplane wing is constructed, and those are covered in tissue paper. Could also go finless with a base drag pyramid. Kind of like the underground portion of the monument support structure.

 

[PhlAsh]

I've been toying with the idea of a 1/100th scale out of foamcore

 

[jqavins]

I was thinking about the rod going right up the middle. But I have a 6' rod (I'm bragging a bit) and I was planning on a meter long obelisk. Using the peak as a guide hole might not work well and getting three holes lined up perfectly would be extremely hard.

My go to answer to this is laser cutting. No, I don't have a laser cutter, but one can find them in maker spaces, in cut-it-for-you companies, and with folks here on TRF. You could then cut the square outlines, motor mount holes, and launch rod holes all at once. You can cut two such centering squares, and square ribs for further up along the length. You could also go that way to cut the trapezoidal sides and triangular cap sides. And you could cut those with notch-tab patterns along the edges (like dental molding) to make them fit together in a goof proof manner. Laser cutters are GREAT!

Don't forget the aluminized paint for the cap stone.