I came across this ambitious project to launch 1U or 3U cube sats into orbit, utilizing a F-104 Starfighter jet and air launching a rocket to achieve this.
The 2 stage rocket is 0.5m in diameter and 5.7m long, burning a combination of hydrogen peroxide and kerosene the rocket is expected to have an all-up mass of 692.3kg. Details on their website are fairly light, but there are a lot of 3D CAD images to be able to scour through to get an idea. Construction is mostly carbon fibre, with the kerosene tank immersed in the peroxide tank
From the pictures, construction is mostly carbon fibre, with the kerosene tank immersed in the peroxide tank for the main stage. A pintle engine injector looks to be used for the main stage engine, which offers throttling capability while also curing combustion instabilities as it does this. The main engine looks also to be of a tube design, just like the Saturn V F-1 engine.
The project ran a Kickstarter to help get the engine development but, unfortunately failed to meet its goal, this has not deterred the team, and they have recently just successfully test-fired an ablative version of the engine, as shown below.
Let’s hope they succeed at their goal and, look out for updates in the future.