rocdoc
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Well, it's that time of the year again. I am getting started on my next project. This build thread comes with my typical disclaimer: The thread will be very photo intensive. I prefer using high resolution photos hosted at another site over the thumbnails. So I apologize in advance if it takes a while to download all the shots.
I have posted a couple other build threads in case you are interested in seeing some of my previous efforts:
The Avenger 5.5 (my first scratch build): https://www.rocketryforum.com/showthread.php?t=10975
The Velociraptor Rex (my L3 certification rocket): https://www.rocketryforum.com/showthread.php?t=16491&highlight=velociraptor
The Avenger was flown two years ago at Fire In The Sky (FITS) over Memorial Day Weekend. The Velociraptor Rex was flown at last year's FITS and again at BALLS last September. I plan to fly the Super Big Daddy twice at this year's FITS. The first flight will be on a single M-impulse motor (probably CTI's M3400WT). This flight will be low and slow and close enough to the crowd that those who normally only see M-flights from the "away cell" nearly a mile from them will be able to see and hear a nearly full size M-motor.
The second flight will be from the away cell with a central N5800 C-star surrounded by four L-impulse air-started motors. This will be my first attempt at air-starts and should be a fun challenge. If all goes well, I may break my normal rule of only flying rockets twice before retiring them and take it down to BALLS to fly on an N and four Ms.
For this build, I will be using 24" diameter concrete forms (Sonotube). The outside diameter of these is actually 24.5 inches. That makes this slightly more than an 8x upscale of the original Estes Big Daddy. The nosecone will be fiberglassed foam. The nosecone itself will be just over six feet tall (not including the shoulder)! I'll be fiberglassing the Sonotube as well. The fins will be fiberglassed plywood. I was hoping to make my first attempt at foam-core fins, but I can't find high density (40-60psi) foam sheets in the right size (1" thick is only available in two foot width and 2" is too thick). Also, the swept fin design guarantees that this thing will land on a fin, so I want to have fins capable of withstanding the impact.
Here are a couple of EARLY RockSim shots showing the basic design. I haven't tried to guess at the weights of materials, so I'm not worried about the stability at this point. Once things are further along, I'll be able to get a better idea as to mass and the center of gravity.
Here is the side shot:
And here is a shot from the aft end. The outboard motors are arranged so they can be secured against the fin tabs. This will help lock in the fins and the motor tubes. The central motor tube is 98mm and the outboards are 75mm.
As always, your comments are welcome. I present these build threads as one way to tackle a build. I certainly don't believe that all my methods are the best for everyone. Feel free to chime in.
Regards,
Bryan
I have posted a couple other build threads in case you are interested in seeing some of my previous efforts:
The Avenger 5.5 (my first scratch build): https://www.rocketryforum.com/showthread.php?t=10975
The Velociraptor Rex (my L3 certification rocket): https://www.rocketryforum.com/showthread.php?t=16491&highlight=velociraptor
The Avenger was flown two years ago at Fire In The Sky (FITS) over Memorial Day Weekend. The Velociraptor Rex was flown at last year's FITS and again at BALLS last September. I plan to fly the Super Big Daddy twice at this year's FITS. The first flight will be on a single M-impulse motor (probably CTI's M3400WT). This flight will be low and slow and close enough to the crowd that those who normally only see M-flights from the "away cell" nearly a mile from them will be able to see and hear a nearly full size M-motor.
The second flight will be from the away cell with a central N5800 C-star surrounded by four L-impulse air-started motors. This will be my first attempt at air-starts and should be a fun challenge. If all goes well, I may break my normal rule of only flying rockets twice before retiring them and take it down to BALLS to fly on an N and four Ms.
For this build, I will be using 24" diameter concrete forms (Sonotube). The outside diameter of these is actually 24.5 inches. That makes this slightly more than an 8x upscale of the original Estes Big Daddy. The nosecone will be fiberglassed foam. The nosecone itself will be just over six feet tall (not including the shoulder)! I'll be fiberglassing the Sonotube as well. The fins will be fiberglassed plywood. I was hoping to make my first attempt at foam-core fins, but I can't find high density (40-60psi) foam sheets in the right size (1" thick is only available in two foot width and 2" is too thick). Also, the swept fin design guarantees that this thing will land on a fin, so I want to have fins capable of withstanding the impact.
Here are a couple of EARLY RockSim shots showing the basic design. I haven't tried to guess at the weights of materials, so I'm not worried about the stability at this point. Once things are further along, I'll be able to get a better idea as to mass and the center of gravity.
Here is the side shot:
And here is a shot from the aft end. The outboard motors are arranged so they can be secured against the fin tabs. This will help lock in the fins and the motor tubes. The central motor tube is 98mm and the outboards are 75mm.
As always, your comments are welcome. I present these build threads as one way to tackle a build. I certainly don't believe that all my methods are the best for everyone. Feel free to chime in.
Regards,
Bryan
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