Engine Conversions and Conversion Kits.

Auto-Moto 4-stroke engines

General information.

Interest in 4-stroke auto-moto engines converting for Light Sport and Ultralight aircraft is growing all over the world. Everyone knows that the most popular 2-stroke Rotax 503 and 582 are not certified aviation engines but variations of snowmobile engines with all 2-strokers' problems. Prices of certified 4-stroke aviation engines are quite high. The active development of aviation piston engines has stopped more than 50 years ago with the jet age beginning. The same time, cars become more and more perfect. Modern auto engines are light, have high reliability and life time. Electronic ignition and fuel injection with microprocessor control system, low gas consumption and flight hour value, simple and inexpensive maintenance with attractive unit price, these features usually distinguish converted auto engine from its "real aviation" brother.

I started to use 2-stroke, then 4-stroke Auto-Moto engines for aircraft in early 90-th. There is a lot of experience in converting of Subaru, Honda, Chevy, Nissan, Kawasaki and other engines but light and small GEO-Suzuki G10 AND G13 are the most interesting engines for me as Ultralight trike builder and pilot. G10 with stock fuel injection has about the same HP as popular Rotax 582 model. Trike with G10 has very good flight performances with significantly lower flight hour cost. Its TBO is about 1000 hours. Its alternator and starter + light battery allow you to start easy at any weather, have headlights, radio, intercom etc. Electronic control module with sensors easy fit it to different temperature, altitude, humidity, gas quality and let you know about possible problems with signal light. You don't need to spend a lot of your time for its converting. G10 Turbo, G13BA and G13BB have about the same power as Rotax 912 and 912S. Trikes with GEO engines operate for crop spraying in Russia and Ukraine. Pilots fly over fields and trees with 10-20 feet altitude with 30 gallon chemical tanks for several hours a day. Heavy conditions demand reliable engines. That is why they use GEO-Suzuki.

Suzuki Power Group (SPG)-2 gearbox conversion kit:

This gearbox was designed for aviation conversion of engines up to 160 h.p. It is in production since 2000. The available reduction ratios are 2.03, 2.34, 2.5. There is a German (BMW) rubber damper between the gear box and the engine. The propeller moment of inertia up to 9,000 kg/cm2. Rotax-style propeller hub, propeller shaft with a hole so it can be used with variable pitch prop or for glider towing. It is possible to use this gearbox for both (tractor and pusher) layouts, install it up, down and any degrees left or right.

The body consists of 3 bolted down parts: 1) gearbox with the gear and oil inside, 2) damper part 3) mount plate (bellhousing) and crank-damper coupler. Bellhousing and coupler are different for different (Suzuki, Subaru, Nissan, Honda etc.) You can see SPG-2 set for GEO (left) and Subaru bellhousing+damper+coupler (right)

The gearbox life-time is 1000-2500 hours (depends on the engine power and the prop moment of inertia). Its manufacturer advices to change bearings after 1000 hours. About 600 gearbox sets have been made. Some of them have 1000+ operating hours. This system is well proven. My customers and I have never had any problem with these gearboxes. I have never even opened one. One of my customers opened one after about 250 running hours. "Looks like new inside" - he said me.

I actually build and fly trikes with Geo-Suzuki engines converted using these kits.

Advantages of this conversion kit are its high TBO and reliability. Using this kit, you don't need to change belts and pay for them. It takes only about 3-4 hours. You will keep a stock water outlet with thermostat. I heard a lot about overheating problem from people using conversions with modified water cooling system but have never had it even with my small radiator closed by BRS system. It is also its high efficiency, much higher than any beltdrive. For example, I got 380lbs of static thrust from my stock unmodified G10 engine with 2.5 RR gearbox and 69" KOOLprop, and up to 550bs from G13 engine. You don't need to modify the engine block so mechanical part of the conversion is very simple-just bolting the gearbox up. SPG-2 conversion manual with step-by-step conversion pictures HERE. Click and look - nothing difficult to convert your auto engine using SPG-2 bolt-on conversion system. Seeing is believing!

All additional parts like mufflers, motormounts with rubber silent blocks, engine control gauges, aviation-style modified wiring harness with double redundancy of important lines, sport camshafts, radiators etc. are also available with all necessary consulting. Some words about our new "small" improvements. For example a set of 3 light (crank, waterpump and alternator) aluminum hard anodized pulleys is not only lighter than one the lightest (waterpump) stock pulley. Increased alternator pulley diameter makes alternator running slower. It allows to avoid alternator overwork (usually we fly higher RPM than drive cars) and win a little bit of HP. Our light alternator set (alternator, aluminum bracket + tighten plate) saves 2.5-5lb of weight comparatively with the stock alternators.

Air Trikes Ent, our clients and partners have made a lot of different engine conversions with SPG-2 conversion kits for the last years. All these engines are working perfectly. Different props are tested for them, and we are ready to supply the best one for your craft. Avia Geo-Suzuki is not just "alternative" engine but well proven and efficient powerplant for experimental aircraft, hovercraft, airboats etc. Installed on trikes, these powerplants have very low gas consumption, about 2.0-2.5 gallons per hour. Now we provide not only conversion kits but also ready-to-install powerplants based on low-mileage stock or completely remanufactured and modified GEO-Suzuki engines:

a) Carburetor G10 with vacuum/centrifugal advance distributor. No electronic control - about 60HP
b) Throttle-body injection (TBI) G10 with DENSO Electronic Control Module (ECM) - 62-65HP
c) Multi Point Injection G10 with modified head and BOSCH ECM – up to 72HP
d) G10 Turbo with MPI, resonance intake, turbocharger – up to 92HP (intercooler & knock sensor can be used)
e) G13BA 8 valves SONS with options mentioned above – up to 115HP
f) G13BB 16 valves SONS 90+HP naturally aspirated
g) G13GTI 16 valves DONS 110+HP naturally aspirated

We sell gearbox conversion kits for Subaru EA-71 EA-81 EA-82 EJ-18 EJ-20 EJ-22 EJ-25 Honda Nissan MA-12
You will find prices for conversion kits and ready-to install engines in Air Trike PRICELIST HERE. We also can design and make mount plates for other auto conversions.

I can't show pictures of all engine conversions made using SPG-2, I have too much of them. Look at my small photo gallery below. Click on pictures with red frames to enlarge them.

Different GEO-Suzuki converted with SPG-2:

Air Trikes sells SPG-2 conversion kits for Subaru EA and EJ:

I decided to make a new page with addresses and feedbacks from some people using our products (including engines and SPG-2 kits) for their aircraft. More pictures there. Look FEEDBACKS PAGE HERE

Year 2007 and Air Trikes new R&D work with engine conversions

I never considered my auto converted engines as "alternative" or "cheap" way of aircraft engine development. Quite the contrary, automotive companies spent hundreds of million dollars for their new engines. We all know about serious competition in this industry for the last decades. As a result, even being cheaper because of mass production, modern auto engine is way more advanced than "real" aviation engines. It is a pleasure for me to design new conversion systems and fly them.

What about motorcycle engines? BMW 2-cyl boxer always attracted me. Everybody knows highest BMW quality, but not all know BMW company was one of the pioneers in aviation engine industry. I and II World War fighters and bombers fly with BMW engines. Light and compact air-oil cooled BMW boxer looks much more "aviation" than most sertified steam-age piston engines we fly now. It is more expensive than Suzuki-GEO but easy to instal under a cowling of most tractor-layout planes. Takeoff company in Germany makes aviaconversions of BMW R1100 and 1150 engines. They are well known and popular in Europe. Regardless the high price (about the same as Rotax 912), hundreds of light panes fly with BMW conversions in Europe.

This is SPG-2 based conversion of BMW R100S. It is a little lighter, more compact and less expensive than German version. 99HP and only about 170LB included 40amp alternator, starter, radiator, ECM... This engine is running now at my test trike. Air Trikes is ready to supply SPG-2 conversion kits, BMW 1100 and 1150 engines like this to the customers. It is an excellent alternative to 912-912S, especially if you need a flat engine to put it inside a cowling but bon't want to lay Suzuki down and Subaru looks heavy for your project. Look at the pictures below.

Can SPG-2 conversion kit be used for other engines?

Yes it can. You see the the Corvair engine on RagWing Stork RW-20 with installed SPG-2 and 73" KOOLprop. This conversion was done by Murray Green from Rosetown Sask. Canada. He noticed increasing of all performances comparatively with direct drive he used before. From his letter to me: "I couldn't be happier. The gearbox and prop seem to be made for the Corvair engine. A wonderful combination."

Look for some pictures I got from Brazil. Trike builders there are used SPG-2 to convert Honda engines they had. The projet is finished and sussessfully flys now. The last picture is a new Russian automotive engine converted with SPG-2. I think it is possible to convert any auto-moto engine up to 160-180HP using SPG-2 kit with custom made or modified adaptor plate and crank coupler.

SPG-2 systems, conversion components available and other useful pictures:

I also decided to make a new page with addresses and feedbacks from SPG-2 buyers. You can ask them about the item and service quality. Look HERE We sold quite a lot of gearboxes but I didn't keep customers' addresses. Waiting for your feedbacks now.

Two-Stroke Engines

General information.

Converted motorcycle and snowmobile engines are also very popular. It is not a secret for example that Rotax 2-stroke UL engines are conversions of Ski-Doo and Sea-Doo motors. A lot of ultralight or hovercraft builders all over the world use such conversions. A lot of redrives exist for them.

5-V redrive system is designed especially for snowmobile engine conversion. This classical system consist of two 6061 T6 aluminum pulleys for 5 V-belts, eccentric shaft with heavy-duty closed ball bearings, motormount plate and all machined parts, rubber elements and hardware necessary for engine installation. It can be made at most of machine shops. I used this redrive with licensed Rotax 640 from 1998 like a powerplant for my "Frigate" trike. It has been installed now with Rotax 503 on my "Eagle" trike. This system has a lot of advantages comparatively with other redrives:

a) Very reliable. Will be working with 4 or even 3 belts. You don't have to be so worried about your belt condition like with your single belt drive.
b) Very light and less expensive comparatively with gearboxes.
c) You can use not only provision-type Rotax but also non-provision. You don't need to convert the engine itself.
d) Spare belts are easy available and not expensive (Car Quest XL serie).
e) Reduction ratio can be easy and smoothly changed by changing the pulley diameter.
f) The engine can be installed head-up or down.
g) This system can be easy adjusted by changing some installation dimensions to almost any project.
h) Quick (a couple of minutes) and easy adjusted belt tension.
i) It is a whole conversion unit included a motormount plate and 4 metal-rubber silentblocks. You need nothing but muffler and prop for your engine installation on a trike or UL plane.

This system is available now as a set of drafts (12 sheets plus description).

Air Trike PRICELIST IS HERE.
For additional information and order E-mail: info@airtrikes.net
Address: Air Trikes Enterprises
6043 Clark street Pierrefonds PQ H8Z 2G3 Canada
Phone: (514) 685-2856