Leap 71
1.3m tall aluminium engine in the unpacking station at Eplus3D’s Beijing facility.
Computational engineering firm Leap 71 has enabled the additive manufacture of two large-scale, single-piece rocket engines in partnership with EPlus3D and Aconity3D, respectively.
E-Plus will showcase what Leap 71 believes is the world’s largest single piece 3D printed rocket thruster at Formnext, while Aconity3D will present a 5kN aerospike engine in Frankfurt. Both engines have been designed and engineered using Leap 71's Noyron Large Computational Engineering Model, which was used to develop the Noyron TKL-5 thruster the company hot fired in June.
The 1.3 metre-tall engine additively manufactured using an Eplus3D EP650-1600 metal powder bed fusion printer is considered a 'distant relative' to the engine that was hot fire tested in June, but is said to be 40 times more powerful. It has been additively manufactured from aluminium, with a 'dual cooling strategy' implemented to keep the engine 'cool enough for propulsion applications.' This dual cooling approach would see cryogenic liquid oxygen used for regenerative cooling of the main combustion chamber, and kerosene for the upper part of the nozzle.
According to Leap 71, the engine was printed in one continuous process for 354 hours, with no post-processing applied. It is believed to weigh around 43.5kg.
In partnership with Aconity3D, Leap 71 has enabled the 3D printing of a 5kN aerospike engine in CuCrZr copper material.
This is considered an 'advanced version' of the TKL-5 thruster the company hot fire tested in June, with the aerospike engine building directly on the test data collected in the summer. The geometry is said to have been generated 'in a matter of minutes' using Noyron, with no CAD used in the design of the engine.
Leap 71
5kN Aerospike rocket engine printed by Aconity3D.
Aerospikes are described as rocket engines that 'forego the typical bell nozzle' and instead have a 'toroidal combustion chamber around a central spike.' Cooling an engine like this is usually challenging since the spike sits in the middle of the exhaust gas and copper melts at low temperatures. Additionally, the shallow and unsupported overhang angles at the throat of the engine can often pose challenges for 3D printers, especially since surface quality is important to ensure the regenerative cooling channels are operating effectively.
Aconity3D is said to have optimised the process parameters of one of its printers to make the additive manufacture of the engine possible. The spike is said to be cooled with cryogenic liquid oxygen through conformal cooling channels, while the outside of the combustion chamber is regeneratively cooled with kerosene. Solukon Maschinenbau GmbH supported the depowdering post-print with its Pathfinder process, while Fraunhofer ILT helped to heat treat the engine. Except for the cutting of the threads, no post-machining is required.
Leap 71 says the engine will be ready to fire after propellant feeds are connected and pressure and thermal sensors are integrated. The company plans to carry out a test fire this year.
The 1.3m tall aluminium engine will be exhibited at Eplus3D's Formnext stand - hall 12.0, booth E101 - while the copper aerospike engine will be presented by Aconity 3D in hall 12.0, booth D02.
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