Hmmm, that is a crazy L/D ratio. If you look at other 98mm motor cases, you'll find that most top out at about 43" or so, or a L/D of about 10, which is considered to be a reasonable maximum. Scott from Loki does have smaller diameter motors that approach your L/D but his 98mm motor case stops at 46". The 6XL case from CTI is just shy of 50". How are you going to mitigate erosive burning in such a long case? The steps in the core will have to be carefully designed and the propellant itself will require careful selection and characterization to make sure it has the right physical properties. Nearly all of the very high ISP propellants from commercial makers use small AP (30 micron) that carries considerably more risk than the larger sizes we typically use.
Scott's K627 and M1378 are good motors to look at to help inform your motor design. Also do some research on Frank Kosdon's long motors - they are in the same L/D as yours. You'll find some references to them in the research section as well as elsewhere on the web.
Tony
here's a good example for Kosdon motors: https://www.rocketryforum.com/threads/o10000-tpl.153963/
(requires access to the restricted research sub-forum)
Scott's K627 and M1378 are good motors to look at to help inform your motor design. Also do some research on Frank Kosdon's long motors - they are in the same L/D as yours. You'll find some references to them in the research section as well as elsewhere on the web.
Tony
here's a good example for Kosdon motors: https://www.rocketryforum.com/threads/o10000-tpl.153963/
(requires access to the restricted research sub-forum)
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