Modification Gravity Rider 224 Modification

Modification - Gravity Rider 224 {Modification}

Contributed by Les Bradshaw

Construction Rating: starstarstarstarstar
Flight Rating: starstarstarstarstar
Overall Rating: starstarstarstarstar
Manufacturer: Modification
Style: Cluster, Futuristic/Exotic

Brief:
After reading Chan Stephens' review, I decided to modify the design to boost the power. I changed from a single 18mm mount to dual 24mm mounts. I also made the ejection charge to vent into the top center tube and eject from the very top.

sunward_gravityrider

sunward_gravityrider_motormountsModifications:
After deciding to upgrade the engines, I looked through my parts pile and found appropriate 24mm motor tubes, centering rings, and engine hooks. I had just purchased RockSIM, but with the multiple tubes I quickly discovered this was not the first rocket to attempt to use RockSIM on. Instead, I figured out the extra weight I was adding with the motor mounts and the D12 engines so I could add some clay to the nose cone to maintain the proper balance. These new 24mm mounts installed into the the tubes the way the 18mm mount would have installed.

sunward_gravityrider_wingletsFor the top end, I measured the shoulders of the nose cones. I lined the top tube with the 2 lower body tubes and made marks to see where the tubes touched. I increased the overlap of the top tube with the 2 lower body tubes to give me room to make my vent slots. These I carefully cut about 3/16 in wide and 3/4 in long. When I glued this tube to the two lower tubes, I filleted the joint somewhat heavily to make sure I did not have any air leaks.

The 2 lower nose cones were then glued into place. I angled these slightly for what I felt was the best look. I went back to my parts pile to find another nose cone to seal the bottom of the top tube. When I glued in the top fins I set these to be behind the new nose cone. This also lowered the fins a bit which would also help maintain the stability.

The tri-fold shock cord mount moved to the top tube. As I indicated earlier, I added about an ounce of clay weight to the top nose cone. The 2 D-12 engines could handle the weight.

Construction:
The kit came with the following:

  • 3 BT-56 tubes
  • 2 BT-50 tubes
  • 3 plastic nose cones with canopy
  • 18mm motor tube and associated rings and hooks
  • 18" parachute
  • Laser cut fins
  • shock cord
  • decals

All the parts were well packed and received without any damage.

Besides my mods, the rest of the build went well and followed Chan's build. However, some of the problems he noted such as the template were already corrected in my version - nice to see the manufacturers listen to the review comments. I still found the instructions for the top fins a bit confusing, but since these were being modified anyway it did not matter to me.

I primed and painted the rocket white. I found Testors had some special tinting spray for car models to simulate windshield tinting. I decided to try this for the canopies.

Construction Rating: 5 out of 5

Flight:
At NERRF 3, I loaded the parachute into the top and 2 D12-5 motors. When launched, the rocket appeared to wobble quite a bit, but quickly straightened out and took off fast and high. I thought I saw something drop off, but I was concentrating on tracking the rocket too much to worry. The rocket went several hundred feet and ejected the parachute and drifted down nicely, although quite a ways down range. The vented ejection charge worked without any issues. When I located the rocket I found one of the large, main fins was missing. I looked around but could not find it anywhere near the rocket. I walked back and as I passed the launch control area, there was my fin on the table. I guess that was what dropped off - no wonder it wobbled! Perhaps dual D's versus a single C did add a bit of thrust. I have repaired the rocket (and used epoxy to improve the joint). Based on how high this went and drifted, I do not have a large enough space where I fly locally to recover this, so I will have to wait for another opportunity where there is a large field (perhaps NERRF 4?)

Flight Rating: 5 out of 5

Summary:
This is a great looking kit, and with the modifications will fly fast and high. I love the scifi and fantasy style kits, and this one was right on.

Overall Rating: 5 out of 5

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