eugenefl
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- Apr 22, 2009
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Ahead of the attempt by SpaceX to test their Raptor engine on the Starhopper test article on 8/26/19, I released an image on various platforms of my scratch build of the Starhopper that I am very proud of and excited to share with you here.
Brief background: I've be a TRF member since late 2001, or early 2002, hard to recall, but I've been an avid supporter of the hobby and basically lived out most of my "online" existence on TRF. I was a child rocketeer in the early 90's, became a BAR in 2001, NAR L1, left for a while, and am now going through a Re-BAR cycle post-40 years of age. Fun fact: I had a brief partial ownership of the forum during some challenging times while in transition into v2.0. Most of my contributions can be found in the old TRF 1.0 archive. I hope not much has changed as I've been away from the hobby for a few years. Having navigated a few social media platforms with rocketry themed groups recently, I still think TRF might be the best long threaded format to document a build, share information, and collaborate with other enthusiasts. I am glad to see this forum is still alive.
For starters, attached is a photo of the near-completed model which I've interchangeably dubbed "Deskhopper" and "DesktopHopper" although I think "Deskhopper" sounds more synonymous with the real thing.
Quick design specs:
- 1/47th Semi-Scale "Eyeball Engineered"; most measurements were taken from visual imagery of the actual test article. I worked on this many late nights after the family was in bed. Being tired played a role in saying "Ah, that's good enough."
- Initially designed for use with a 24mm SU AeroTech F21-4W, I installed a core 24mm midpower MMT tube. That may have been a design error as this model is nearly at neutral stability, with a slightly positive CG/CP relationship and will require more nose weight likely making a 24mm MMT inadequate based on motors I've researched. I may at some point either add 2 side core MMTs and cluster it or remove the 24mm center mount and install a 29mm tube.
- Diameter = 7.7", air frame is made of internal 1/4" foam skeleton discs wrapped with poster board.
- Leg/Fins = this was a buildup of dowels wrapped in body tubes to simulate the thickness of the legs used on the real test article.
- Nose cone = Floral foam half-sphere, shaved down to approximate height and curvature. This will require a little more trimming, but being that it's "sport scale" I can live with it. If I increase any variables in thrust, I may shave it down again, and coat it with a lightweight fiberglass. At the moment it's "static display ready" with wood filler, primer, and silver paint.
- "Raptor" engine (removable, display only) = Estes Nose Cone (#72057), cut to size. The remainder of the nose cone will make a nice boat tail for some other build.
- "Stainless Steel" = Oy...80% of my time was spent painstakingly hand cutting and placing each piece of self-adhesive chrome reflective vinyl. Originally intended to have panels cut by a Cricut machine, my wife was on Elon time so I had to move forward and use a ruler and hobby blades. I may have to learn the interface for that thing so I can cut my own stuff in the future. But, it was worth it. The panel counts are accurate to the exterior of the test article. Mis-alignment was intentional, and very much a relief for an OCD person like me. I'm glad SpaceX was in a hurry too.
- Build time = About 1 month start to finish.
Main Goals/Drivers:
- Reconnect with the hobby and it's people via social media and in-person launches. I've been away for a while. I figure a project that could gain visibility and interest wouldn't hurt. There are lots of nice folks in rocketry.
- Feel like I'm a part of the commercial space race, at hobby scale.
- Commemorate a test article that is now retired after only 1 tethered hop and 2 test hops.
- Build a flyable model that likely won't get much replay in the hobby enthusiast market, but will be recognized by space fanatics.
Stretch Goals:
- Merit a "like" from Elon or Gwynne Shotwell, or both, but for very different reasons. That'd be instant printable souvenir material. I'm afraid I might never meet Vern or Gleda in person for an autograph , so I'd be thrilled to garner the acknowledgement of the man at the forefront of the SpaceX company himself or the lady that drives the operations and growth.
- Accomplish a "scale like" hop. I've run enough calculations to determine that it is entirely feasible on an Estes E9-P.
- Consider a conversion to use a BPS Signal R2. The real test article was intended to hover. I think the Signal R2 is the perfect application for this scale model. Of course, the model would have to achieve a high enough altitude to survive a parachute deployment, but the low thrust and low speed climb would look amazing.
Design Inspiration: A few names come to mind.... Tim Dodd (Everyday Astronaut), @JoeBarnard , Oli Braun (Buzz Space Models), Boca Chica Maria, Scott Manley, Martin Molin (of Wintergaten/Marble Machine), countless spaceflight photogs, and the many nameless/faceless SpaceX engineers that do this stuff for real. We just get to be the fun cheerleaders building flyable trophies in our spare time.
I'll be adding some build photos in the days to come. Please let me know if you have any questions, comments, suggestions, etc.! Thanks for checking out this really long initial build intro thread.
Brief background: I've be a TRF member since late 2001, or early 2002, hard to recall, but I've been an avid supporter of the hobby and basically lived out most of my "online" existence on TRF. I was a child rocketeer in the early 90's, became a BAR in 2001, NAR L1, left for a while, and am now going through a Re-BAR cycle post-40 years of age. Fun fact: I had a brief partial ownership of the forum during some challenging times while in transition into v2.0. Most of my contributions can be found in the old TRF 1.0 archive. I hope not much has changed as I've been away from the hobby for a few years. Having navigated a few social media platforms with rocketry themed groups recently, I still think TRF might be the best long threaded format to document a build, share information, and collaborate with other enthusiasts. I am glad to see this forum is still alive.
For starters, attached is a photo of the near-completed model which I've interchangeably dubbed "Deskhopper" and "DesktopHopper" although I think "Deskhopper" sounds more synonymous with the real thing.
Quick design specs:
- 1/47th Semi-Scale "Eyeball Engineered"; most measurements were taken from visual imagery of the actual test article. I worked on this many late nights after the family was in bed. Being tired played a role in saying "Ah, that's good enough."
- Initially designed for use with a 24mm SU AeroTech F21-4W, I installed a core 24mm midpower MMT tube. That may have been a design error as this model is nearly at neutral stability, with a slightly positive CG/CP relationship and will require more nose weight likely making a 24mm MMT inadequate based on motors I've researched. I may at some point either add 2 side core MMTs and cluster it or remove the 24mm center mount and install a 29mm tube.
- Diameter = 7.7", air frame is made of internal 1/4" foam skeleton discs wrapped with poster board.
- Leg/Fins = this was a buildup of dowels wrapped in body tubes to simulate the thickness of the legs used on the real test article.
- Nose cone = Floral foam half-sphere, shaved down to approximate height and curvature. This will require a little more trimming, but being that it's "sport scale" I can live with it. If I increase any variables in thrust, I may shave it down again, and coat it with a lightweight fiberglass. At the moment it's "static display ready" with wood filler, primer, and silver paint.
- "Raptor" engine (removable, display only) = Estes Nose Cone (#72057), cut to size. The remainder of the nose cone will make a nice boat tail for some other build.
- "Stainless Steel" = Oy...80% of my time was spent painstakingly hand cutting and placing each piece of self-adhesive chrome reflective vinyl. Originally intended to have panels cut by a Cricut machine, my wife was on Elon time so I had to move forward and use a ruler and hobby blades. I may have to learn the interface for that thing so I can cut my own stuff in the future. But, it was worth it. The panel counts are accurate to the exterior of the test article. Mis-alignment was intentional, and very much a relief for an OCD person like me. I'm glad SpaceX was in a hurry too.
- Build time = About 1 month start to finish.
Main Goals/Drivers:
- Reconnect with the hobby and it's people via social media and in-person launches. I've been away for a while. I figure a project that could gain visibility and interest wouldn't hurt. There are lots of nice folks in rocketry.
- Feel like I'm a part of the commercial space race, at hobby scale.
- Commemorate a test article that is now retired after only 1 tethered hop and 2 test hops.
- Build a flyable model that likely won't get much replay in the hobby enthusiast market, but will be recognized by space fanatics.
Stretch Goals:
- Merit a "like" from Elon or Gwynne Shotwell, or both, but for very different reasons. That'd be instant printable souvenir material. I'm afraid I might never meet Vern or Gleda in person for an autograph , so I'd be thrilled to garner the acknowledgement of the man at the forefront of the SpaceX company himself or the lady that drives the operations and growth.
- Accomplish a "scale like" hop. I've run enough calculations to determine that it is entirely feasible on an Estes E9-P.
- Consider a conversion to use a BPS Signal R2. The real test article was intended to hover. I think the Signal R2 is the perfect application for this scale model. Of course, the model would have to achieve a high enough altitude to survive a parachute deployment, but the low thrust and low speed climb would look amazing.
Design Inspiration: A few names come to mind.... Tim Dodd (Everyday Astronaut), @JoeBarnard , Oli Braun (Buzz Space Models), Boca Chica Maria, Scott Manley, Martin Molin (of Wintergaten/Marble Machine), countless spaceflight photogs, and the many nameless/faceless SpaceX engineers that do this stuff for real. We just get to be the fun cheerleaders building flyable trophies in our spare time.
I'll be adding some build photos in the days to come. Please let me know if you have any questions, comments, suggestions, etc.! Thanks for checking out this really long initial build intro thread.
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