The Oat Propulsion Laboratory presents our latest Descon 10 entry

by Emmanuel Camburako

The Name
Descon 10 - Roman numeral 10 is X. Typical designation for an experimental aircraft is X. Thus, this experimental aircraft designation is the X-10 or X-X. Double X

The Double X has been designed as a vehicle to investigate the practical application of a ground to near earth orbit manned intercept vehicle. The mission for such a vehicle would be to take off in a conventional manner, attain a low orbit, intercept hostile incoming weapons systems and return safely to home once again.

Mission Parameters
For this project it was determined that in order to be competitive in the current market the NEO intercept vehicle would be designed and built using existing technology and off-the-shelf parts (Gemini DC). To keep research and development costs to a minimum only existing airframe, motors and tooling would be considered.

The Parts
Use this link to view the list used for the design and construction of the Double X near earth orbit intercept vehicle.
Parts list
The only variation from the parts list is that balsa nose cones were used for the NC-20's. Typical plastic NC-20's may be used but the construction technique originally used balsa. For simplicity balsa was used for this application. 

The Design
As with most designs, inspiration is is the most important part of the process and the most elusive element of the method. The long list of past and present X-planes and rockets had a great impact on the source of inspiration. The most obvious influence is the famous Douglas X-3 Stiletto. Less obvious is the Estes Rocket Plan #55 a.k.a. Excalibur which can be viewed on JimZ's site. Critical construction techniques were borrowed from this very nice design.
Missing from this entry is the traditional oat cereal box which has become the trademark design element of the OPL.
Sorry kids, maybe next time...

The templates needed are included through links on this page.

• Vertical stabilizer template
• Horizontal stabilizer template
• Wing template
• Alignment guide

The general layout design and preflight testing was done using VCP and SpaceCad. Both files are included here. Because of the relatively complex nature of the airframe cross section it was necessary to simplify in the simulation.

Construction
As stated in the description part of the construction technique is taken from the original Excaliber. This is important as there is a newer version which does not employ the same construction methods.

What this applies to is the engine nacelles so we'll do that first. Split both of the BT-20 recovery system pods from the Gemini kit in half lengthwise avoiding the ejection duct holes. Cut one NC-20 in half lengthwise to be glued into one end of each of the tubes you just cut. The next step is to make the nacelle assembly fit to the contour of the main airframe BT-50 by gently sanding away the part of the n/c that interferes. Wrap a sheet of fine grit sandpaper around a BT-50 (reinforcing the tube with couplers or whatever is a good idea) and slowly sand inside (hollow) part of the nacelle assembly back and forth lengthwise. Test fit often. 

Glue a BT-20 thrust ring to a piece of card stock, carefully cut out the circle when dry and bisect the assembly. Sand the flat edge of the semi-circle to fit the main airframe. This will become the inlet of the engine nacelle and will be painted black.

Using the fin templates cut out each of the fins making note of two of each one being left and one being right side. Use typical fin techniques.

Trim BT-50 to 14.5 inches in length. Mark tube using alignment guide for all of the lines. These parts line up at odd angles, so pay close attention to which part goes on which line.

The motor mount will protrude 1/2 inch from the back of the rocket. This will eventually be painted black. Use whatever motor retention device you are fond of.

Typical shock cord and parachute mounting using one of the 12 inch chutes.

Flight
The flight simulation and actual flight reports can be viewed from this page.

Flight simulation using the prototype design  layout in SpaceCAD.