Background, company overview and products...
Since the widespread popularity of the internet began back in the mid 1990s, we have read a lot of on-line discussions as to what makes a good VW conversion and how the conversions differ from one manufacturer to another. Great Plains subscribes to a few of the lists - just to keep up to date on "the topic of the day". As a company we rarely reply to internet groups, only making the occasional response to an individual in the group, if the group does not come up with an "appropriate answer or answers", in a reasonable time as it pertains to our product or services that may be discussed.
We believe that commercial responses over time would detract from the groups, perhaps remove some of the free exchange of information that takes place daily between group members. This exchange of information be it correct, incorrect, positive or negative, is overall helpful and informative for those participating.
We have noticed time and time again the discussion about how the conversions currently in the market place differ from each other, but have never seen a detailed discussion, point by point, as to how our company, company's engines, and components are different from the competition. So we'll fill in the details.
Great Plains Aircraft had been commercially selling VW engine kits, and conversion parts continuously since 1982. This year (2015) we mark our 33rd year in business. In the U.S., only RevMaster has been selling VW conversions for sport aircraft for a longer period than us.
We have seen many companies come and go in the U.S. in those past 33 years that have sold VW conversions, and or parts, or plans. To name some: Able, HAPI, Mosler, TEC, Barker, Monnett Experimental, INAV, Christeen Aero, Duty, R.J Huggins, Limbach and others. Why we remain in business and all these other companies or individuals have come and gone in those years, we will let you, the consumers continue to decide.
Being a small company, one wears many hats. The positive side is that with every order, we strive to fill it and ship it in a manner that we would expect from any other company that we would do business with. Do we make occasional mistakes? Sure. But we strive to treat the customer as we would want to be treated. Great Plains Aircraft has maintained it's positive position in the marketplace because our company offers a wide range of time proven products at reasonable prices and we maintain this with a minimum overhead. It's the overhead that dooms many small companies when the market is slow or flooded with short term competition.
The most popular engine configuration is the Front Drive (direct drive) engine. This is driven off the pulley end of the crankshaft. Displacements from 1600cc up to 2276cc are available. A wide variety of accessories and accessory packages are available. From single ignition, to hand start, to dual ignition, 35 amp 3 phase alternator, accessory housing and geared starter. The choice is yours.
The Reduction Drive has really opened up the range of aircraft that can use VW power. Direct drive VW's are limited to a 62" diameter prop because of tip speed. They will produce about 200 to 250 lbs. of thrust, depending upon prop manufacturer. The reduction drive engine can turn prop diameters from 72" with a 1.6:1 ratio and up to a 84" prop with a 2.0:1 ratio. Static thrust with a 72" prop is about 350 lbs. The 2:1 ratio with a 84" prop will deliver about 450 lbs. of thrust.
The most popular engine sizes for the Reduction Drive are the 1915cc, the 2180cc and the 2276cc motors. We have Accessory Packages for the Reduction Drive engine. The standard Accessory Package for the Reduction Drive features a starter, 35 amp 3 phase alternator, 009 type distributor, choice of drive ratio, top mounted carburetor and intake manifold, accessory case and remote oil cooler. They can be fitted with either dual electronic ignition or can use one magneto and one electronic ignition system. The re-drive VW engines are used in many of the WW1 type aircraft, several of the Cub look-alikes, and Storch replicas. They can deliver outstanding take off and rate of climb, when matched to the correct aircraft. The main limitation of a re-drive aircooled engine is heat.
For starters, we offer many Type 1 VW engine parts and accessories and individual parts for sport aircraft. Bearings, cams, stud kits, heads, cases, accessory case kits, cool tins, carburetors, secondary ignition systems, magnetos, plugs, wire sets, 2 different prop hub styles, instruments, piston and cylinder sets. You get the idea!
So what makes our products different?
Ok, let's examine some of our products!
The heart of the engine is the crankshaft. It has to be able to absorb, dissipate and transmit. Our 82mm forged E4340 steel crankshaft is made specifically for aircraft use. It features a rectangle flat milled key for the prop hub. The crankshaft has a 3 degree taper on it that is mated to our Force One prop hub. The bolt that retains the hub is a fine thread bolt that is 3.5" long. The threads in the crankshaft are machined in the crankshaft about 3" down from the end. For the first 1.250" the thread is relieved so the pulling or retention loads is placed at the rear of the thread in the larger diameter of the crankshaft. This crankshaft is made specifically for the rigors of driving a propeller. It is not an "out of the box" automotive crankshaft as used by one competitor. In the 25+ years this current crankshaft design has been manufactured, it has never suffered a failure. Our E4340 crank is manufactured from a forged billet and machined in the USA. 69mm crankshafts are made from a 4140 forging.
The Force One Prop Hub and Main Bearing.
While not totally unique to aviation, it is in many respects when combined with our crankshaft. We recognized from early on from a number of crankshaft/prop hub failures with 82mm crankshafts and shrink fit and short tapered hubs, that perhaps it was not the best way to build stroker engines for longevity.
The Force One Prop Hub rides in a engine lubricated bearing that the case is machined out for. The Force One Bearing is pressure lubricated, utilizes 2 seals for oil control. The total bearing area has 4 to 5 more surface area than does a standard #4 position, VW bearing. But the important point is the hub is supported in the bearing instead of being attached forward of the bearing, as is the case when using a shrink fit or standard tapered prop hub. As the fit between the hub and the crank is on a 3 degree taper, it can be removed repeatedly without wearing out either tapered surface. With shrink fit hub, the .002" interference fit will eventually erode with multiple removals.
With our Force One Hub, we can still use the brass distributor drive gear to drive a secondary or primary ignition system. Another competitors crankshaft does not have the brass gear on the crankshaft and cannot use a primary or secondary ignition in the distributor hole.
2180 and 2276cc Camshafts.
Our camshaft, while based on a popular design for automotive use, is custom ground to our specifications for aircraft use. It is designed to provide maximum horsepower and torque in the 3000 to 3400 rpm band. We keep the duration low and add enough lift to pack the cylinder as full as possible. This cam lets the engine idle without lopping and offers quick acceleration without stumbling. Other manufacturers use standard off the shelf automotive camshafts. All our 2180cc and 2276cc kits come with new lifters. These kits also feature 5/16" steel pushrods (no aluminum here for higher lift cams) and new rockerarm assemblies.
Most of the other hard components will be standard from whom ever you purchase your engine parts from. The case, pistons and cast steel cylinders, oil pumps, cylinder heads, gasket sets and the like, all come from a small source of manufacturers and will be pretty common to all conversions.
This is another area where we are very different from some of our competitors. Starting with the Accessory Case, we supply a fully "closed" accessory case. This simply means the flywheel is enclosed in the case. One competitors X case features an open rotating flywheel. With our accessory case the starter position can be ordered in the 12:00 or 6:00 or 9:00 position.
We have a standard 35 amp 3 phase Alternator that is mounted inside the accessory case. One of our competitors has only a 20 amp single phase alternator for standard equipment. The 35 amp 3 phase alternator does not produced any RF noise for an aircraft radio or navigation system.
Almost 30 years ago we started using the Geared Starter which you now see as standard on most VW sport aircraft conversion. This lightweight 8.5 lbs. starter has an internal start solenoid, eliminating the need for an external one.
Our Flywheel is unique to the industry. We are the only company we know of that builds and uses a light weight 100% steel flywheel, weighing in at only 5.5 lbs. Other companies use a combination of aluminum and steel to keep the weight down. We can boast that the steel flywheels have never had a failure. Aluminum and aluminum/steel ones can't say that.
Primary Ignition. Yes, we still use what some competitors describe as old and antique - a magneto. But there is a good practical reason that is lost on some. The Slick 4220 magneto, does not need a power source, does not have external rotating magnets, is easy to hook up, and most important, you can start the engine by hand if the battery fails. With one competitor's ignition system, if the battery is dead or the starter is broke you won't go anywhere until you replace one or both. Their engine has to rotate 200+ rpm to start the engine. No starter, no battery - no starting.
Secondary Ignition. We offer a wide variety of secondary ignition systems that will fit just about any application. Our standard low height secondary ignition system (only 1.310" tall) fits in the standard VW distributor hole. This ignition system is the "standard" secondary on most of our engines. This system must be in the off position when starting.
009 Distributor. The 009 distributor can be used as a primary or secondary ignition system. When the cap is replaced with our 90 degree distributor cap it makes a lower height/attractive installation. The 009 can be upgraded to electronic ignition if needed.
Oil Pump Secondary Ignition. This ignition system replaces the oil pump cover plate. The bottom driven gear of the pump is modified and a shaft engages the gear. This system uses the same components as our low height system.
The Low Height Secondary and Oil Pump Secondary Ignition Systems all feature dual redundant coil packs and can fire spark plug gaps up to .042" if required.
Take a look at our web site. You will quickly see that we offer a wide range of products for VW sport aircraft engine conversions - period!
We know that even after 34 plus years of being in business, we still don't know it all. We are constantly learning about these timeless engines. We do believe that when you purchase one of our engine kits or parts, you will be purchasing the absolute best, safest, time proven VW based engine available in the market place for your aircraft.
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