LOC Viper IV
- Length:
- 123cm / 48.5"
- Diameter:
- 6.5cm / 2.5"
- MMT:
- 4x 24mm
- Status:
- Flown
Comments:
Originally I bought a LOC/Precision Viper III, which I flew at UKRA 2000 on three E30-7 Aerotech motors. It flew extremely well, but unfortunately, I lost it in the crops. When I next dropped in at Rockets and Things to buy a replacement, I just HAD to get the Viper IV version, which is a little larger and has 4-motor cluster.
The Viper III and Viper IV design is exactly the same apart from the number of motor mounts and the airframe size. The motor mounts stick out of the back of the airframe by some inches, and the fins surface mount directly to the motor mounts. The fins are the same high quality aircraft ply used by LOC/Precision for all of their kits, and cannot be faulted. The airframe is also the robust quality kraft paper tube from LOC.
Construction is very easy indeed. The 3 or 4 motor mount tubes (depending on version) fit into two pre-drilled cluster centering rings, and everything is epoxied together. The fins are best attached at this stage too. When everything has cured, the complete motor-mount/fin assembly is just epoxied inside the airframe. Finally, the shock cord installation is just like Estes, with its tri-fold paper.
The only modification I made was to epoxy a short length of all-thread into the void between the motor-mount tubes. A nut and washer can then act as a motor retainer. In hindsight, I would actually suggest that you epoxy a nut into the void. Just grease the threads and use a greased bolt to help install it, and remove the bolt before the epoxy cures. You then use a small bolt an washer as the motor retention. This is much safer, with no sharp pointy thing ready to take someone's eye out, and also it makes transport easier so you won't dig holes in the car furnishings.
My first Viper III was my introduction to Aerotech propellant. I chose 3 E30s because the Blue Thunder propellant is the easiest to light, and also because I was concerned that it would not fly well on Estes D motors. I was in fact completely wrong. Both the Viper III and Viper IV fly perfectly well on Estes D motors, and on Aerotech, they fly out of sight very quickly! To install the motors, just wrap a few wraps of masking tape around the nozzle end of the motor to act as a thrust ring. Then install the motors, and tape in place or use the nut/bolt motor retention. To avoid a misfire, I seriously recommend the use of Quickmatch for clusters. Although prepping time is longer and a little more fiddly, you will have a 100% success rate at lighting clusters.
Simulation:
Rocksim Simulation Results are available for this rocket. These results have been automatically generated from the Rocksim file.
Flight Log:
| Flt. | Date | Location | Motor(s) | Impulse | Recovery | Comments |
| 1 | Aug 2003 | Largs IRW | 4x D12-3 | 80 Ns | LOC 'chute | Caught in bottom branch of a tree, but was easily retrieved! |
| 2 | Aug 2004 | Largs IRW | 4x D12-3 | 80 Ns | LOC 'chute | Nice flight |
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