[chasd00]

the amateur rocketry crowd has had large solid rocket motors for a while now but bi-propellent motors (event the most simple designs) are very very rare. If you could design one in the N impulse range and price it at < $2500 they'd sell like hot cakes. Then you could scale up the design to a bit more powerful and sell it to universities at around 10k a pop. The service contract to keep them running would be worth a lot o f money too. Eventually, you'd be able to sell a Karman line capable kit and that would sell like hotcakes to both the amateur rocketry and university crowd.

There's a group on youtube working on nitrous oxide/methanol engine for hobbyists now. I think they're headed in the right direction although I would have done the combustion chamber differently. https://www.youtube.com/channel/UCEkE_gf1VxBngLugexHz2KQ