The Sadler Radial
The Sadler Radial Engine is a compact, fuel efficient and smooth running aircraft engine. The 6 cylinder radial uses two banks of three cylinders with power pulses every 120 degrees of revolution. The design uses VW cylinders and pistons for reliable inexpensive parts. The engine is a great alternative to 2 stroke power. Prototype testing has proven out this radial and casting patterns have been made. The engine is ready for final pre-production development. Our goal at the '04 Sun 'N Fun is to gauge the public's interest in the Sadler R1765U and determine if we can take the final steps in bringing this engine to market. Please let us know if you think the Sadler R1765U may fit any of your aircraft needs. We think this is an exciting opportunity for uncertified aircraft owners but we need your feedback to determine the future of the project. Give us a call or drop us an e-mail to let us know. We look forward to hearing from you!
Configuration: Direct drive, 6 cylinder, four-cycle, internal combustion, gasoline fueled, free air cooled engine, one gravity fed carburetor, and a dry sump lubrication system.
· HP/Torque @ 3000 rpm--65 hp/113.4 Torque ? Displacement--1721cc (105 cu in.)
· Stroke--50 mm (1.969 in.) ? Lubrication: dry sump, pressurized
· Bore--85.5 mm (3.366 in.) ? Rotation--clockwise, view from rear
· Compression Ratio--9.5:1 ? Option--Electric start
· Accessories--oil cooler, oil tank (4 quart)
· Engine weight with components (dry) - 108 lbs. (Prop. Start)
· Engine weight with electric start/alternator systems--122 lbs.
· Engine diameter--20.7 in. plus oil system components below engine
ENGINE PERFORMANCE (WITH 66" , 2 BLADE, WOOD PROP.)
· Normal rated power, T.O. 62 bhp @ 2,850 rpm
· Max. rated power 65 bhp @ 2,975 rpm
· Continuous rated power (90%) 58.5 bhp w/avg. fuel burn of 4.1 gph or spc=.44 lb./bhp-hr
· Typical cruise power (75%) 49.5 bhp w/avg. fuel burn of 3.4 gph or spc=.43 lb./bhp-hr
· Idle Speed 800 rpm
Information compiled from a review of the design drawings, test stand operation of the engine under conditions whereby accurate measurements of the related parameters could be made (torque, rpm, temperatures, pressures, etc.) and test operations in aircraft. All figures from independent source. Patent No. 5,150,670
THE SADLER RADIAL ENGINE DESIGN
· The Sadler Radial Engine project objective was to design a reliable, lightweight, four-cycle, aircraft engine in the 65 horsepower range. Below are the parameters, which were considered essential:
· Air cooled
· Duel ignition
· Minimized design risk through utilization of off-the-shelf components, where available
· Low R.P.M
· Minimum vibration
· Low fuel consumption
· Light weight
· Low noise level
The pistons and cylinders are standard Volkswagen, extensively machined. The use of these stock Volkswagen components provides for a ready supply of spare parts, and eliminates any piston-cylinder interface design risk problems.
The valve train is unique in that it uses only one
single small diameter cam for all inlet valves and another identical cam to
drive all the exhaust valves. Each tappet housing holds all of the six
inlet or exhaust roller tappets. The hardened steel cams run on
ball bearing integral shafts to drive the roller tappets. The tappet
housings are staggered in the rear case and drive overlapping pushrods to
each rocker arm. Because the valves are arranged in line
lengthwise along the engine (placing exhaust forward and inlet rearward) and
the pushrods all come out of the engine rear case in a single plane, each
rocker arm for a given cylinder is displaced laterally to the left or
right of the cylinder centerline. This allows the front exhaust
rocker arm to miss the inlet valve and spring, as well as allowing the rear
rocker arm to be similarly displaced from center, making room for the
inlet manifold to pass between the push rods on its way to the cylinder head
Full pressure lubrication is supplied from a rear
case mounted oil feed pump running at camshaft speed. Inlet oil to the
oil pump comes directly from a remote oil tank. A four-quart oil supply
is recommended. Because the cylinder bases protrude into the crankcase
cavity, very little back oil finds its way into the lower cylinders.
IGNITION and ELECTRICAL SYSTEM
our plans are to use the self-contained SmartPlug* system.
manifolds may vary according to application as the four-cycle characteristics
do not require a tuned exhaust.
We believe that the Sadler R1765U lives up to it's initial design criteria. It is a compact, light weight, fuel efficient, four-cycle engine. Since the project began, approximately 43 prototypes have been built. There are almost 500 hours of dynamometer testing and the engine has also been successfully test flow on several different aircrafts. All testing indicates great potential and, therefore, we feel this engine has an exciting future.
THE FINAL STEP
Pressure Engines has begun an initial evaluation of the Sadler Radial
Engine. We hope to be able to determine the market's interest in the
Sadler R1765U, so that we can confidently commit the necessary resources to
complete the final pre-production phase of the project.