Rotary Rocket | Hacker News Reader

Rotary Rocket

en.wikipedia.org

30 pointsbane13 comments

Perhaps surprisingly, the tip jet dates back to about 1908 and was patented at least as early as 1911. Clearly surprisingly, the inventor and patent holder was Ludwig Wittgenstein who was pursuing a PhD in the white hot tech field of aeronautics at University of Manchester.

It is also when he discovered Russell and Frege and the rest is the history of 20th century Anglo philosophy.

Such dead ends might not be useless.

Many Rotary rocket alumni went on to found XCOR where they're building a suborbital winged rocket plane. XCOR's also lined up to provide a piston pumped rocket engine for the ACES upper stage for ULA, which could mean very flexible in space operations (long coast times).

An interesting related fact, one tip jet helicopter actually made it into the production, the Sud-Ouest S.O.1221 Djinn (http://en.wikipedia.org/wiki/Sud-Ouest_Djinn). According to Wikipedia 178 of them were built. In this case the tip jets were simply powered by compressed air.

How come this vehicle doesn't self spin around the rotor axis? Like a traditional single rotor helicopter would do without the tail rotor?

The tip jets supply the rotational power so no torque exists (other than some friction) between body and rotor to cause body rotation.

https://www.youtube.com/watch?v=7Kp63-an2ts

In the 2000-2001 time frame a lot of us watched in amazement? disgust? at certain dot-com valuations, and Rotary Rocket starved due to lack of funds. It makes one wonder about how capital is allocated. People made conscious decisions to invest in a sock puppet versus a technology that gets humans into space.

The wikipedia article makes it look like the design was inherently flawed. Entirely possible that venture capital was (at least subjectively) allocated badly AND this project shouldn't have received more funding anyway.

An SSTO is an ambitious design in general. That, plus a new engine design, was (in retrospect) too much for a startup company to take on. Just the powered landing system would have been ambitious enough.

If there's ever some kind of standard that emerges for rockets maybe a company like this can make an interim payload stage to add to recover the vehicle. Like how satellites are gaining more and more standard parts and form factors.

As presently any system like that I assume is pretty must bespoke per rocket family.

As presently any system like that I assume is pretty must bespoke per rocket family.

Yeah, but the original engine was not the standard LOX/kero turbopump affair. The seals were breaking new ground, if nothing else.

I don't get why is that so baffling -- the whole premise of VC is to invest in projects that offer a high return in a short period of time, at the cost of the high risk that they will fail. That risk is offset by a large volume of similar investments, meaning that low-cost opportunities are much more interesting.

Hardware and energy intensive technologies -- like rockets, satellites and the like -- definitely fail at both the time and cost criteria (and their risk rate is not quite among the lowest). That means that they'll get invested in only by entities which are capable (and willing) of investing large amounts for long periods of time, while willing to accepts significant risk -- which reduces the group to governments, large companies like Google and determined individuals like Musk and Branson.

So, capital is allocated considering a number of criteria, the perceived risk being among the most important. The key word here is _perceived_, as in the late nineties a lot of investors started believing in the myth of endless growth, which significantly lowered the risk they perceived on sock puppets and the like.

Gary Hudson always inspired me as an entrepreneur who would not give up. My brother finished his last year of law school remotely so he could join Hudson in Claifornia. I started my first consulting company while still in college to do structural analysis on Hudson's Percheron Rocket.

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