The original prototype of the Aero Commander was given the designation of Model L3805 For his book Stars and Commanders, Dave Duntz conducted years of research, including with Ted Smith’s unpublished memoir. The memoir was published in chapter 7 of Duntz’s book, and will be presented here in three parts. This is the second installment. You can purchase Duntz’s book at www.starsandcommanders.com.
So far, a name for the company had not been established nor had a name for the product been chosen. We all gave these subjects serious thought for names are important. The company should define the type of business and the product name should identify it with its purpose.
Names were finally chosen: The Company name was Aero Design and Engineering, the significance being that we were dealing with aircraft design and engineering. Then the name of the aircraft: Aero, again meaning something to do with aircraft and the word Commander, having the definition of being in command. So, it all fit together, the name of the product Aero Commander – an aircraft in command or a leader over all others, so significant for its time, a new aircraft designed to be in command of a new era in aviation, a tool for business, a pioneer in a new world of aviation in the years to come.
We incorporated Aero Design and Engineering Company on the 31st day of December 1945. Shortly thereafter we applied for and obtained, through our legal counsel, a permit to sell stock at $1.00 per share. Permission was granted by the California Commissioner of Corporations to give the originators of the Company a controlling interest in the Company known as promotional stock in the amount of $55,000.00. We were given permission to sell $50,000.00 worth of stock to the public at $1.00 per share, and we were also given permission to give stock to our employees at the rate of three shares of stock for each hour worked. All of this had to be done within the State of California and sales made strictly to California residents, by California law.
In the end, we sold $50,000.00 work of stock for cash and it was a big thing when we sold 10, 20, 50, or 100 shares to one person. This was the general trend for it was difficult in those years for people to have much faith in what we were doing. However, in one case a gentleman flew in from Las Vegas, Nevada (although a California resident), landed on Culver City Airport, came into my office and wanted to know more about our program. I showed him thed to know more about egas, Nevada (although a California resident), landed on Culver City Airport, mockup, described in more detail what our plans were, and he pulled out a large roll of bills, placed $2,000.00 on my desk and said he wanted to be a part of our program. I almost fell over backwards, but I was able to maintain my calm, thanked him for his generosity, made out the stock certificate for 2000 shares of stock—the largest single block of stock we had ever sold to that time, and as it turned out later it was the largest single block of stock that was ever sold. Other sales were made, but rarely over 100 share blocks and most were an average of 50.
We had applied for a type certificate through the Los Angeles regional office of the C.A.A. At that time the Chief of the Engineering Branch was George Haldeman. George had a long background in aviation including an attempt to fly the Atlantic with Ruth Elder, a famous aviatrix. Shortly after making the application, I visited with George and his staff. They were located in a war-built building on Century Boulevard formerly used by Douglas Aircraft Company, El Segundo Division, for the engineering staff during the war.
This brings to mind that during the war all engineering departments of the various companies were diverted to locations away from the manufacturing divisions and all manufacturing buildings were camouflaged in such a way that it was very difficult to recognize them from the air.
The Douglas plant in Santa Monica was so well done that one of our pilots returning from a production flight about dusk, mistook the false runway for the real one and almost landed directly on top of the main plant since the camouflaging incorporated the false runway with the areas of the overall camouflaging. Fortunately, the pilot realized his mistake in time and immediately pulled up and went around to land on the regular runway at the Santa Monica Airport.
My visit with George Haldeman was a very pleasant one and both George and his staff were very interested in the project presented, agreeing to cooperate and help in any way possible. Certain of his people from the various sections were assigned to the program and we worked directly with these people during the development of the Aero Commander project.
Shortly after the first meetings with George Haldeman, a change came about in the F.A.A. region. George Haldeman was replaced with Armor Alcorn who became Chief of the Engineering Branch of the Western Region, and all of our contacts with the Chief of the Engineering Branch were with Armor Alcorn whom we found to be very understanding just as George Haldeman had been.
Certification basis was under Part 4 of the C.A.A. regulations which was the current regulation at the time and covered all types of aircraft including air transport; designing to Part 4 requirements was one of the reasons that the Aero Commander was able to grow in power and gross weight quite easily without major change since Part 4 was much more stringent than the later Part 3 and still later Part 23.
We proceeded to develop the basic load criteria which is the first document presented to the region for the start of engineering type approval.
From here, since all basic dimensional data had been developed through mockups and layouts, we proceeded to loft the aircraft, made layouts of the major components such as wing, empennage and fuselage, layouts of control systems for primary controls, engine controls and trim. All control systems were of cable and pulleys with all bracketry of sheet metal construction.
The original prototype of the Aero Commander was given the designation of Model L3805 meaning Lycoming powered with a total of 380 H.P. and 5-place seating. Design work progressed and approval of the basic loads with minimal change was received from the C.A.A. late in 1946.
The airfoil section of the wing was the fairly new NACA 23012 section that had excellent lift coefficients and fairly low drag characteristics for airfoils during the 1940’s. This airfoil section was the latest for subsonic use although a new laminar flow series of airfoils were being developed for transonic use. These were in test at N.A.C. in the mid-forties. The latter are today in general use on military as well as commercial aircraft.
One adverse characteristic of the NACA 23012 was that it had a very sharp break at the stall, and it was necessary to build a negative twist into the wing to keep the wing tips at a lower angle of attack when approaching the stall to avoid sudden wing tip drop out. The Commander wing was built with a negative 3-degree twist from the inboard end of the aileron to the wing tip which was calculated to prevent any adverse characteristics at the stall.
The wing area as shown in the specification was 244 square feet with an aspect ratio of a little over 8 and a taper ratio of .33 with a swept forward trailing edge of 14 degrees and a straight leading edge for reasons given in the description on wing structure design and power plant installation.
Wing structure was laid out and the basic structure of the wing was of two spar design: one main spar at 35% chord and one rear spar at 67% of the chord. There was also a short spar at 15% of the chord with a fitting at the inboard end of the spar to attach to the fuselage to assist in transferring torsion from the wing into the fuselage structure.
The wing was built in three sections: a center section 290 inches long extending from a rib station at 145 to the same station on the opposite side, the center section carried through the fuselage and was attached to heavy fuselage frames with 3/16 diameter rivets. The center portion of the wing was designed as a cavity for a bladder cell for fuel, as were the sections just outboard left- and right-hand sides. It was calculated that the total fuel would be 156 gallons with the capability to install additional fuel cells in cavities outboard of the engines giving an additional fuel capacity of a little over 33 gallons per side for a total of 223 gallons including expansion space.
A very simple fuel management system was designed wherein the main fuel system of 156 gallons fed directly to a center sump and from here through on/off valves to each engine. The simplest fuel management system ever designed for an aircraft, and as time went on, the fuel management system proved to be the safest and simplest of any in the industry.
As the design of the wing design progressed, a Frise type aileron system was designed with differential movement. When the aileron was up 25 degrees on one side, the opposite aileron was down 15 degrees. This prevented adverse yaw when aileron control was needed and also gave very effective aileron control in the deep stall regime. Perfectly coordinated turns could be made using only the ailerons.
The flaps were in two sections: an inboard section between nacelle and fuselage and an outboard section from outboard the nacelle to the inboard end of the aileron. All four sections were interconnected through a cable and pulley system extending across the fuselage. A push/pull tube at the center of the fuselage was connected to a hydraulic cylinder which powered the system. The flaps were designed as a simple slotted type, raising CL (Coefficient of Lift) values about 25% at the half down position and further raising CL values and adding drag in the full down position. Maximum CL value obtained with flaps down was 2.1.
