RGClark
Mathematician
By airframe-free I mean with no body tube, so for example the fins are connected directly to the motor casing. This would require a great deal of experience to pull off, which is why I’m proposing it only for L3 certified rocketeers.
As discussed in this post, it would result in a radical reduction in the rocket dry mass, and therefore a radical increase in altitude:
Unexpectedly high RASAero estimate for a two-stage rocket.
https://www.rocketryforum.com/threa...te-for-a-two-stage-rocket.145740/post-1783286
Note, with the university student team at USC achieving a flight beyond the von Karman line for suborbital space, it should no longer be considered a “bad word” for amateur rocketeers to discuss the rocket they thus designed also breaking the von Karman line.
The most common way of attaching the fins is by way of a fin can:
Altitude Expectations for a Minimum Diameter 54mm.
https://www.rocketryforum.com/threa...r-a-minimum-diameter-54mm.146209/post-1789560
However, with many experienced rocketeers devising their own methods of managing it, likely more lightweight means could be achieved.
By the way, apparently a term in use for an airframe-free amateur rocket is “subminimum”:
98mm subminimum diameter.
https://www.rocketryforum.com/threads/98mm-subminimum-diameter.162595/
This is because competitions have been mounted for “minimum diameter” rockets. These are when the rocketeer tries to get the wall thickness of the body tube or airframe as thin as possible. So not using a body tube at all is referred to as subminimum. It’s not a very appealing term. So I’m looking for a better term to use.
Bob Clark
As discussed in this post, it would result in a radical reduction in the rocket dry mass, and therefore a radical increase in altitude:
Unexpectedly high RASAero estimate for a two-stage rocket.
https://www.rocketryforum.com/threa...te-for-a-two-stage-rocket.145740/post-1783286
Note, with the university student team at USC achieving a flight beyond the von Karman line for suborbital space, it should no longer be considered a “bad word” for amateur rocketeers to discuss the rocket they thus designed also breaking the von Karman line.
The most common way of attaching the fins is by way of a fin can:
Altitude Expectations for a Minimum Diameter 54mm.
https://www.rocketryforum.com/threa...r-a-minimum-diameter-54mm.146209/post-1789560
However, with many experienced rocketeers devising their own methods of managing it, likely more lightweight means could be achieved.
By the way, apparently a term in use for an airframe-free amateur rocket is “subminimum”:
98mm subminimum diameter.
https://www.rocketryforum.com/threads/98mm-subminimum-diameter.162595/
This is because competitions have been mounted for “minimum diameter” rockets. These are when the rocketeer tries to get the wall thickness of the body tube or airframe as thin as possible. So not using a body tube at all is referred to as subminimum. It’s not a very appealing term. So I’m looking for a better term to use.
Bob Clark
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