Auto Engines for Aeroplanes

The Ford V6 made in Windsor, Ontario, Canada has been on the market for nearly two years in various Ford cars and trucks. The actual displacement of the 3. 8 litre Ford Windsor V6 is 232 cubic inches and with our 2 to 1 reduction drive that’s a swept volume per prop rotation of 462 cubic inches which compares with the 0-470 Continental. The Continental completely ready to fly weighs 488 pounds. Our 230 V6 complete with reduction drive and all accessories weighs 387 pounds.

The performance of an airplane is tied to the power to weight ratio of the engine. This is why we were attracted to the Ford Windsor V6. Its weight compares to the Model A Ford engine that Pletenpol flew, but this modern engine with our reduction drive delivers five times the horsepower.

There are several aluminium block V8s being operated by direct drive. They are only getting 125HP though and they weigh 425 pounds. That’s a power-to-weight ratio of 3. 4 pounds per horsepower which means very poor performance. We flew the Arrow Sport years ago with the Ford flathead V8, 82HP and 700 pounds; it flew but just barely, the power-to-weight ratio was 8. 5. The objective is to equal a Lycoming or a Continental in power-to-weight ratio at around 2 to 1 and we are doing this with the 230 V6 at 260HP. The V6 is 1. 49 pounds per HP. The V6 is 8. 8 to 1 compression ratio as opposed to 7 to 1 on the Continental 0-470 which means we get considerably more power from the equivalent displacement.

Aircraft engines never idle as well as automobile engines and camshaft characteristics are the reason why. The stock camshaft develops maximum torque at 2200 RPM to get across the intersection when the light turns green. This low RPM is low horsepower and to get an airplane over the fence on take-off requires horsepower. With our new camshaft, we shift the maximum torque to 4400 RPM and with our reduction drive we get the power we want. They are designed to use non-leaded premium automobile gas. They have better propeller efficiency due to lower RPM, while they are rated at 4800 RPM but the propeller shaft is turning at 2400 RPM. This means we can turn a bigger propeller and make less noise. And due to liquid cooling, our engine is quieter and It uses half as much fuel. Air-cooled engines require excess fuel for cooling, we cool with coolant in- instead of gasoline.

We flew the first flight on the V6 March 12, 1984, and it is a sensational engine we have dreamed about for more years than we care to admit. The engine is quiet and smooth with tremendous power.

For you guys (and girls) that want to go 200 MPH on 6 gallons per hour in a two-place aeroplane, we’ve got the engine to do it. If you want to build a 160 MPH four-place, we’ve got the engine to do it. A new Continental or Lycoming costs $20,000, you can build this engine for $3,000. A major overhaul on a Continental or Lycoming can cost $10,000. We can major overhaul ours for under $1,000. We use basically the same reduction drive on both the model 98T and the V6. The reduction drive works perfectly, we never touch it. It gives perfect service. In years to come homebuilders will be doing all sorts of things to their homebuilt engines, but the reduction drive won’t change, it is set in concrete. We have done a complete development job on the model 98 but if Ford makes changes we will be keeping you advised.

Some of our builders want high HP for their replica fighters so just as soon as Ford starts delivering the V6 with the turbochar- ger we will put one in our flight test airplane and tell you how to do it. You will be able to switch the reduction drive from the V6 to the turbocharged model, Ford does not change the bell housing mount. The fundamental change to convert an automobile engine to an aircraft engine (if it is not turbocharged) is to change the camshaft. Automobile engines have a torque curve that is different from the power curve. The torque curve and the power curve are the same on an aircraft engine. The 230 V6 had the best automobile camshaft we had ever seen with maximum torque at 2200 RPM (but only on 70 HP); the aircraft camshaft we developed moved the torque curve over to 4400 RPM. This much change cannot be expected normally, this was a case of going from one extreme to the other.

The highest power we recorded on the dynamometer with the temperature and altitude corrections was 280 HP at 5200 RPM and 15 gallons per hour. We can consistently make runs at 263 HP at 4800 RPM and 12 GPH. (The Continental 0-470 uses 27 GPH at rated power. )

With this data we have established a rating of 260 HP at 4800 RPM. Dynamometer runs at 22 inch HG and 3600 RPM show 105 HP and 6 GPH (5. 8 actual). The specific fuel consumption at rated power is . 39 and at cruise power is . 37. This performance is with the Holly electronic leaning carburettor. We use full rich at rated power and full lean at cruise. ” Joe Horvath, head of Rexmaster Aviation, 7146 Santa Fe Avenue, East, Hesperia. Cal. 92345, is equally lucid in extolling the virtues of their particular products:

“In the past it was generally assumed that aircraft using smaller horsepower engines did not require supercharging simply because they normally operate at lower altitudes. Traditionally, it was also felt that because superchargers increase the weight and cost of an engine, they were of no particular benefit to engines of less than 200 HP. ” Basically, supercharging increases an engine’s power output by compressing more fuel/air mixture into the cylinders than would be induced by normally aspirated atmospheric pressure alone, thereby creating greater burning pressures. But to take full advantage of supercharging, the engine must be matched with an appropriate constant speed (CIS) propeller, a further expense.

To meet this challenge, Revmaster put together an experimental package deal, using Shillings Q2 as a testbed, and the results are sufficiently exhilarating that the “Turbo 75” Revmas- ter 2100D-T (for Dual Ignition, Turbocharged) will soon be marketed.

The “package deal” includes three elements that will fall into a rough price range of $4,800 for the basic engine, $1,500 for a Maloof/Revmaster CIS propeller system, and $300 for a governor/tachometer, totalling around $6500. (Without the computerised governor, the propellor functions in a two-position mode using a simple toggle switch. ) Advantages exist not only at altitude at lower flight levels, sea level to approximately 5000 feet MSL, but smoother and more efficient power delivery is also quickly apparent. But where a normally aspirated engine loses horsepower with increasing density altitude, turbocharging overcomes that problem, up to what is called a critical altitude, where it will no longer produce 100 per cent of sea level power. Thus, whereas the Continental 0-200 of 100 horses at sea level delivers only 75 HP at 7500 feet MSL, the turbocharged R2100D-T of 75 horses at sea level maintains that same power output at 7500 feet MSL. That is, says Horvath, only if you are using a constant-speed propeller. A fixed-pitch propeller cannot take advantage of turbo-charging at altitude simply because the air is thinner, which enables the propeller to overspeed. When that happens, to protect your engine you must throttle back, and so defeat what you’ve gained in extra power.

Different engines have their own idiosyncratic differences and recently Shilling found he was getting sea-level power at 11,500 feet MSL flying with 36 inches of manifold pressure and 3200 RPM (full power). This translated into a Vmax of 178 MPH IAS, or 220 MPH true airspeed at 14 degrees C OAT. To understand more about Shilling’s remarkable Turbo 75 Q2, you need to know more about the man. He flew with Chennault’s Flying Tigers outfit in 1941 to 1942 around Rangoon. Most of his 25 missions against the Japanese were photo-recon flights, although he did score one kill. After the war Shilling flew C-46s and C-47s with China National Airways Corp. and China Air Transport, then DC-7s for Swissair, before retiring.

At 67, Shilling’s 27,000 flying hours total an amazing 1125 days, or more than three years in the left seat, and now, In the homebuilt area, he’s still going strong. His first homebuilt was a Cassutt racer, which he raced at Reno in 1969, finishing in fourth place, which was not bad for starters. Next he built a Sonerai II so he could take his wife and kids flying in a similar type. “Then when I joined Revmaster two years ago,” he says, “I decided to build me a Q2, largely because it came the closest to advertised performance claims”. His Q2 made its maiden flight in March 1983, behind a norm- ally aspirated Revmaster with a wooden prop; then he switched to a Maloof/Revmaster propeller and flew in the Cafe 400 at Santa Rosa. “I had no flight test time on the new prop and cowl- ing, so I didn’t do too well,” he admits. At this point Horvath was already experimenting with the turbocharged engine on a KR-2; then, in July 1983, Shilling made his first flight with it under a new, longer cowl in his Q2.

Initial flight tests with the Turbo 75 were revealing. At 630 pounds empty and 850 pounds gross weight, he averaged 1000 fpm to 12,000 feet MSL, where he hit a Vmax of 208 MPH IAS on 75 per cent power (24 inches, 3000 RPM). He was then used a two-position Maloof propeller, without the CIS governor. Shilling installed a Rajay 300 series turbo-supercharger, now manufactured by Roto-Masta, at the front end of his engine, which required an extended cowling and a recessed area in the firewall in order to take the starter/magneto accessories. The entire power train totalled only 217 pounds. Amazingly. Shilling found he could get 90 HP, briefly in an emergency. “Not all of the advantages of a ‘blown engine’ are derived at altitude,” he points out. “The turbocharger is driven by exhaust gases, and the fuel/ air mixture goes through the unit, so you get what is called a ‘wet’ turbo, with the impeller helping to mix the fuel and air more completely. The result is that each cylinder gets an even mixture, and I can lean to peak EGT rather than to the leanest. cylinder as in a normally aspirated engine there’s just no lea- nest cylinder. ”

Normally aspirated, his engine delivers 65 horses, yet turbocharged it puts out 75 plus HP, so he likes to rate it at an honest 80 HP, but still calls it a Turbo 75. The Revmaster R2100V- T uses a floatless carburettor, and bigger intake valves with a new alloy, harder valve seats and valve guides with a higher silicone content for better lubrication in order to handle the greater heat. Up front, Shilling uses a 12-inch spinner instead of a 10-inch standard size, which provides a semi-annular intake to the blower. Such design features turn the engine into a real performer, particularly on a hot day when the density altitude is high.

“All the engine knows is density altitude,” he reminds. “Flying out of Albuquerque on a 40-degree C hot summer day, the engine thinks it’s up at 12,000 feet MSL; hence normally aspirated engines would only put out around 50 horses instead of 75. Turbocharged, my Q2 ceiling is around 20,000 feet MSL Instead of 16,000, while an unblown engine on a high-DA day would have a service ceiling of only 12,000 to 13,000 feet MSL. ”

Thirdly, the Advanced Engine Design of G 3283 S Dort Hwy. . Burton, Michigan 48529. put out a range of engines based on the popular Kawasaki motorcycle engine and they have developed these engines for use in homebuilt and ultralights with a matching 2:1 or 3:1 transmission which can also be used on Cuyuna, Rotax and several other makes of light two-stroke engines.

So you see there are plenty of people actively engaged in developing some sort of auto engine for use in airplanes and these are probably quite acceptable in the USA with their Experi- mental Category but I strongly suggest that before you rush off and buy one of these beauties to put in your beloved homebuilt, check with your Airworthiness man in your DoA Regional Office. You may not be able to use it in Australia – it could end up as a very expensive tie-down.