Banana shaped rocket?

[Bravo52]

Any thoughts on a banana shaped rocket? What about a “Horseshoe Crab” shaped body. I guess what I’m aiming for is an asymmetric body tube. In my limited “fluid dynamics” experience, funny shape tend to produce weird lift vectors and that can be a little exciting at times on a ballistic trajectory. Inputs and or examples would be great. TIA
v/r
Jerry

 

[MaxQ]

The Flis ACME Spitfire broke some ground in this area....

 

[Bravo52]

The Flis ACME Spitfire broke some ground in this area....

Yea that's true and I thought about that rocket, but as I recall, the nose cone and the engine thrust vector are aligned and the shapes are pretty balanced. That being the case, it seems that the odd shape only produces drag and not odd lift vectors (I guess in extreme cases it could).

 

[powderburner]

Also, the configuration of the Fliskits Spitfire has some sharp corners that shed and disrupt (subsonic) airflow along the length of the rocket. This tends to stifle most of any lateral "lift" forces that might occur, as opposed to the smooth curvy sides of a curved or banana-shaped object. There, the flow would try to remain attached and would definitely develop some non-standard aero forces.

Bravo52, you might somehow luck out and have a straight (or semi-straight) flight profile without special mods---you'll have to do a little private flight testing, of course. If you go ahead and try to eliminate screwy or unpredictable lateral loads, you might be able to shed all the local laminar flow by covering the surface of the rocket with something aerodynamically "rough?" Maybe a few rings of tiny vortex generators spaced along the length?

 

[AX'E]

HMM.....My first upon finally adding to this post are but one...
Which way do you want the rocket to launch- vertically, with the curve facing laterally (sideways); or horizontally with the curve facing top-or bottom?

AX'E

 

[kramer714]

I have a similar question, I'm working on a level 3 design with a triangular cross section. The cross section will be constant except in the front and rear where it will transition back to round. Think something like a CALCM without the air scoop. Can rocksim model this kind of cross section? What about locating the fins? (on the 'flats' or on the tips?).

My baseline is an equilateral triangle with the legs being 10 inch long and each corner a 1.5 inch radius. I plan to build the body in three sections, each 4' long I am planing to build a truss with the three corners taking all the axial load (three cylinders), and the flats taking the torsional load and a bit of the bending.

As a side note, I don't plan to use the nosecone for the parachute but use a side 'door' like on my last rocket, sounds complicated but simplifies a bunch of things

 

[uncle_vanya]

I have a similar question, I'm working on a level 3 design with a triangular cross section. The cross section will be constant except in the front and rear where it will transition back to round. Think something like a CALCM without the air scoop. Can rocksim model this kind of cross section? What about locating the fins? (on the 'flats' or on the tips?).

Fliskits Caution Rocket and Nebula both are triangular - one uses a flat side attachment that ends up looking like a corner placement - the other has a weird/elegant tube-fin-like design.

I think that the sharp edge where the boy comes together will be a zone of turbulence - which would recommend to me that you consider placing the fins on like the Fliskits Caution rocket or through the flat sides to the MMT.

I would also expect this design to have higher tendancy for the body tube to contribute to the lift which means that a long rocket might be a problem. Barrowman assumes that the rocket's body makes insignificant contributions to the calculations of CP - this is probably not true in this case.

 

[Breeze1913]

Alright, so when are you gonna design and build the Banana shaped rocket?