USS Prometheus

The USS Prometheus is a low-power kit from Red River Rocketry.  This was my first kit from Red River, and I must say the quality of the parts was excellent all around.  This is a light model, that is recommended to be flown with A, B and C motors.

Most unique for me in this kit was the bright gold Mylar parachute. It was almost unbelievably light - we'll see how it holds up to repeated flights and the occasional 'not enough wadding'.  It should be very visible from the air.  The balsa nosecone, fins, decals, body tube, shock cord, decals and all the other components were first-rate.  My only concern was the string to be used for the parachute, which although it might be strong, was very thin. Thin is more likely to cut through the parachute material, so I substituted it with my normal multi-colored string and made the lengths 1-1/2 the diameter and added a fishing swivel clip.

The "story" behind this is that this is a futuristic cargo transport ship.  They make another model that is a fighter/defender of this ship because of it being attacked by aliens.  My concern: I dont have that model yet, so my Prometheus may be vulnerable to alien attacks.



Construction went well, and this was my first introduction to using Titebond's filler glue for the fillets. It works well, but I should have used a little more to get really smooth results.  Fortunately, the priming and painting went well, with no crazing from the Rustoleum paint this time. It would have been a nightmare to sand out all the hard-to-reach nooks on this model.

As usual, I did add a payload compartment for an altimeter to this model, but instead of retro-fitting a payload, I incorporated it into the initial design, by cutting a three-inch length of the body tube instead of adding to the length of the rocket.  Basically, the only penalty is the weight of the altimeter and padding, and the bulkhead (which was balsa in this particular case).

In addition to the payload section, and parachute risers, other modifications include laminating cardboard to all the fin surfaces before sanding and priming, adding standoffs for the launch lug and hollowing out a portion of the nose cone (for payload space).  A few minor extra decals were added to the design.

There was one other construction technique I tried for the first time on this rocket. This involves punching/poking small holes in the fins and body tube before gluing.  The theory is that more glue will get into these internal spaces and act as small "rivets" of glue to help hold the parts together.  At least this provides more surface area for the glue to make a stronger bond. I find it also helps to "suck up" more of the glue and gives the excess a place to go instead of squeezing out and running.  This will hopefully provide more strength in the fin area, which considering this particular design, it might need it. Here is a look at this technique (as done to a different rocket).

SPECIFICATIONS

Series Number: 31
Number of Stages: 1
Length: 22"
Payload Volume: 2.64 cubic inches
Diameter: 1.325" (BT-55)
Wingspan: unmeasured
Vertical Rudder Height: unmeasured
Engine Pod/Tube Fins: 3
Basic Stock Weight: 76.7 grams
Payload Section Addition Weight (Bulkhead,padding): 5.6 grams
Total Weight with Altimeter: 89.2 grams
Liftoff Weight Range: 108-113.4 grams
Motor Diameter: 18mm
Motor Length: 70mm
Motor Mounting Method: Clip
Recovery Method: Parachute
Parachute: 12" Mylar
Recovery Protection Method: Wadding
Shock Cord Material: Kevlar & Elastic
Nose cone material: Balsa
Fin Material: Balsa, Cardboard Laminated
Completion Date: May 27, 2013