Day 0: Design frozen, parts and motors ordered.
This is my second project scaled specifically for my new field/group with G power limitations. My first project was a +70% upscale up of the USS Andromeda to 24mm/F-G power (build thread here). This build is a semi-scale downsizing (-25%), of an HPR original 4" design I built in the 90's. The booster pods are still 24mm but in smaller diameter tubes, the central motor has been downsized from 29mm to 24mm. In the original version the 29mm did all the heavy lifting, the 24mm motors contributed little other than fire and smoke (which is always cool). The new MPR version is much more versatile in motor configuration, it should be able to fly on a single F or G but when using D or E power in the center the booster pods will be critical for flight. The booster pods were also lengthened to make use of the nose cones and body tubes from 3 Baby Bertha kits (source: Hobby Lobby) without the need to trim down the tubes. I will also be experimenting with a "poor man's" electronics free dual deployment system... the pods will eject drogue shoots at apogee, the central motor will have a maximum delay motor to eject a larger chute a few seconds later.
This is my second project scaled specifically for my new field/group with G power limitations. My first project was a +70% upscale up of the USS Andromeda to 24mm/F-G power (build thread here). This build is a semi-scale downsizing (-25%), of an HPR original 4" design I built in the 90's. The booster pods are still 24mm but in smaller diameter tubes, the central motor has been downsized from 29mm to 24mm. In the original version the 29mm did all the heavy lifting, the 24mm motors contributed little other than fire and smoke (which is always cool). The new MPR version is much more versatile in motor configuration, it should be able to fly on a single F or G but when using D or E power in the center the booster pods will be critical for flight. The booster pods were also lengthened to make use of the nose cones and body tubes from 3 Baby Bertha kits (source: Hobby Lobby) without the need to trim down the tubes. I will also be experimenting with a "poor man's" electronics free dual deployment system... the pods will eject drogue shoots at apogee, the central motor will have a maximum delay motor to eject a larger chute a few seconds later.
