EXPjawa
Well-Known Member
OK, back at URRF3, I ordered a Scorpion kit from MAC Performance. I probably won't have normally bought a kit of that type or size (or price), as I'm mostly a low/mid power guy despite being L1. But, I had several onsite vendor vouchers for $10 each, which the event staff gave out as a reward for working a shift at the event. So, I had to find a use for them...
Anyway, they were sold out of what they'd brought to the event, but were willing to put my name on one when they got back home. In ensuing conversations with Mike Crupe, I asked him to make a few minor changes. I decided early on that I wanted to build it with an Aeropack boat tail motor retainer. Since this requires the motor mount tube to protrude farther aft than normal, I wanted to extend the mount tube past the standard 12". I had him replace that with an 18" piece, so that it would be more of a stuffer tube. The other change that was needed to accomodate the retainer was the rear centering ring (normally a stepped thrust ring) was replaced with a standard ring that could be recessed into the body tube. So, that sums up the changes. I also bought the Aeropack piece and a fin jig from Mike.
With all that ordered (Mike was kind enough to deliver to the following URRG launch), I set about modifying the Rocksim file downloaded from the MAC site. I wanted to get an idea of what I was dealing with, and of course, it was not too early to start thinking about finishing and color schemes.
Rocksim output:
Once I received everything, the first step was to take it all to work, and put all the parts on the mass comparison scale in our lab. It measures to the 1/1000th of a gram, so I could update the model with accurate values. As you might guess, adding a chunk of aluminum to the tail while pushing the motor farther back didn't do the stability any favors, but I should still be able to have a reasonable margin without ballast - at least withing the range of motors available to an L1.
As far as coloration goes, you can see above that started with all-silver like on MAC's site, but added green to the nose, and threw in some roll pattern for good measure. The green itself is a texture file generated from an image of Ford "Gotta Have it Green", a 2013 Mustang color. While I probably won't use automotive paint, the Testors Lime Ice lacquer seems a near match.
Anyway, they were sold out of what they'd brought to the event, but were willing to put my name on one when they got back home. In ensuing conversations with Mike Crupe, I asked him to make a few minor changes. I decided early on that I wanted to build it with an Aeropack boat tail motor retainer. Since this requires the motor mount tube to protrude farther aft than normal, I wanted to extend the mount tube past the standard 12". I had him replace that with an 18" piece, so that it would be more of a stuffer tube. The other change that was needed to accomodate the retainer was the rear centering ring (normally a stepped thrust ring) was replaced with a standard ring that could be recessed into the body tube. So, that sums up the changes. I also bought the Aeropack piece and a fin jig from Mike.
With all that ordered (Mike was kind enough to deliver to the following URRG launch), I set about modifying the Rocksim file downloaded from the MAC site. I wanted to get an idea of what I was dealing with, and of course, it was not too early to start thinking about finishing and color schemes.
Rocksim output:
Once I received everything, the first step was to take it all to work, and put all the parts on the mass comparison scale in our lab. It measures to the 1/1000th of a gram, so I could update the model with accurate values. As you might guess, adding a chunk of aluminum to the tail while pushing the motor farther back didn't do the stability any favors, but I should still be able to have a reasonable margin without ballast - at least withing the range of motors available to an L1.
As far as coloration goes, you can see above that started with all-silver like on MAC's site, but added green to the nose, and threw in some roll pattern for good measure. The green itself is a texture file generated from an image of Ford "Gotta Have it Green", a 2013 Mustang color. While I probably won't use automotive paint, the Testors Lime Ice lacquer seems a near match.