This project was particularly fun because I did it jointly with my wife Yvonne. The goal of the project was to refurbish a M1078 LMTV for civilian use as a chassis for an expedition truck. The chassis is large enough to accommodate a 110 square foot living module with a total vehicle weight of up to 26,000 lb. A completed expedition truck based on a M1078 can be capable of remote operation for several weeks without supplies, can be US registered as an RV, and drive-able with a normal Class C driver’s license.
The M1078 is a member of the basic LMTV utility truck family in the US military. The family includes 4×4 and 6×6 chassis for a wide variety of uses. We acquired the base 1996 4×4 M1078 truck from government surplus.
This project took us a little over a year and required refurbishment, painting, power coating, and replacement of many vehicle parts as well as the fabrication of many new custom items.
I became interested in long distance sailing after reading the experiences and life philosophies of Bernard Moitessier and Joshua Slocum. The simple efficiency and economy of traveling the world by wind is appealing. Proas are a type of traditional South Pacific two hulled outrigger sailboat. From a design vantage, I’m interest in modernizing ideas while respecting heritage. Proa are asymmetric with one large hull (aka) on one side and a small hull (ama) on the other. On a Pacific Proa the smaller ama is always kept to the windward side of the boat. The ama acts as a counterweight and provides righting moment against sail load subsequently negating the need for a keel. Proa are therefore not tacked like a normal sailboat; they are “shunted” keeping the small ama to the wind. This means that the bow and stern of the boat are identical, and the direction that the boat is traveling changes with each shunt. The absence of a keel and having the small ama lifted high in the water makes Proa have unique sailing performance and potentially very high long distance cruising speed.
I sized this Proa for a couple to comfortably live full time while long distance worldwide bluewater cruising. Using the Leonard/Starzinger empirical cruising speed method, I sized this Proa for a theoretical average daily mileage of 167.5 kt mi/day (able make the California to Hawaii passage in 12- 13 days). The aka accommodates a full sized galley, head with shower, and large storage areas. There is ample room for a normal queen sized bed in the overhanging lee pod.
Before I started this project, I received flight training in several different gyroplanes to better understand the differences in handling and performance. Of all the aircraft that I have ever flown, gyro flying has by far been the most enjoyable flying experience. The intent of this project was to build a one-off, stable/docile, open, two place, gyro with good visibility for fun local flying and short cross country flights. I started my configuration study by benchmarking my basic layout against 15 other gyros for comparison.
During the design process, I checked 82 different weight and balance scenarios and iteratively refined the configuration to establish as little CG movement as reasonably possible. The structure was monolithic carbon fiber/epoxy/Divinycell with localized fiberglass and Kevlar buildups. There were also localized carbon unidirectional tow reinforcements. The horizontal stabilizer was epoxy/fiberlass/polystyrene with unidirectional pultruded carbon fiber spar caps. The fuselage tooling method was a seamless composite shell molded over a removable CNC milled foam male tool.
The vertical and horizontal tail volumes compared well against other benchmarked tractor gyros. The vertical stabilizer and rudder were positioned in the cleanest air available on the underside of the fuselage. The intent was to maximize yaw stability with the nose raised at high power and minimize spiraling-slipstream turn/roll tendencies.
I compared 44 different engines for this application in the 85-150 hp range, and I decided to go with the Rotec Radial R2800 swinging a 76×57 Culver wood prop. The overall gyro design was based around the R2800 from the beginning. The rotor was intended to be a RFD 28 ft aluminum rotor with RFD double-bearing rotor head.
The gyro is now being finished by a gyro enthusiast in Oregon.
This project was the design of the spring steel landing gear for the tandem tractor gyroplane that I was concurrently developing at the time. The main landing gear were modified Cessna 140 landing gear legs.
I used an iterative Finite Element Analysis (FEA) method to tailor the leg spring stiffness to produce the desired deflection at max landing weight and expected landing descent rates. I milled the width of the Cessna 140 gear legs down to the specific analyzed dimensions. Also, I canted the legs out for a wider stance while still producing the same root bending moment of the heavier C140. This wider stance required special axle mounting blocks to set the proper axle angle. I analytically designed the axle block angle to produce level axles with the aircraft sitting static at a nominal weight. The gear was sized per configuration applicable FAR23 load cases. The rolling stock was FAA/TSO Parker Hannifin 500-5.00 with single puck differential hydraulic brakes.