SPG-2.

General info:

The gearbox is designed for 4-stroke auto engine conversions up to 140HP and using them with propeller for NOT SERTIFIED experimental light aircrafts, hovercrafts, airboats etc. It can be used for tractor and pusher layouts. TBO is about 1000 hours. It is recommended to check and possibly change bearings and rubber dampener after 1000 running hours.

The gearbox set consists of 3 main parts bolted together:

1)    Gearbox with gears and oil inside.

2)    Damper housing with BMW damper

3)    Bellhousing (different for different engines)

Assembling and installation info:

Assembling and installation on the engine is quite simple procedure. No necessity to modify your engine to install the gearbox. Look at our step-by-step pictures below.  E-mail Air Trikes l if you are not sure how to assemble it even after seeing them. Some important notes:

1)    Some engine components can be different. For example, there are 2 different types of starter flywheels + automatic flex plate for Suzuki-GEO engines. It is possible to use a “flexplate sandwich” (2 flexplates bolted together) for more smooth than with a singe flexplate running. It is also possible to use a custom made flywheels. We supply a “universal” coupler which can be used with all of them but you have to modify your flywheel or make a simple spacer for your flexplate to fit them to the coupler. We supply drawings if necessary.

2)    The SPG-2 manufacturer don’t supply crankshaft, bellhousing and starter bolts because they are different for different engines. We are going to supply them for GEO, with other necessary bolts (for motormount L-bars for example) soon. List of necessary bolts for GEO-Suzuki:

M10 x 1.25 L30 – 6 (crank) preferably with 14mm head

M10 x 1.25 L35-40 – 1

M10 x 1.25 L45-50 – 1

M10  L55 with lock nuts – 2

M8 x 1.25 L 45-50 – 2 (starter)

You can buy them (at least 8.8 grade) in a local hardware store. Metric bolts are not common in Canada and US. For example, we use L35 crank bolts with 14 head, Standard bolts L30 have 17 head so more difficult to torque them. We cut them a little or use washers as they are longer than necessary.

3)    Torque crank bolts sequentially with 5 ft. lb. increments to 29 ft lb. Torque 6 rubber damper bolts to 22 ft lb.  Use blue locktite to secure all bolts even if locknuts are used.

Gearbox break-in:

Must be done with a propeller.

1) Fill the gearbox with gear oil 75W90 or 85W140 70ml more than the level of the side plug.

2) Start the engine. Run it from idle, slowly increasing RPM up to MAX for one hour.

3) Stop the engine, pour the oil out, clean the gearbox inside with kerosene (diesel oil).

4) Fill the gearbox with fresh gear oil 75W90 or 85W140 again 70ml more than the level of the side plug. Install security wire to each plug

Gearbox maintenance:

Check the gearbox visually during preflight outside (oil leak, cracks, safety wires) and inside through the windows (rubber damper, crank and damper bolts, cracks of the shafts).

Change the gear oil each 50 running hours or one year.

We don’t recommend to open the gearbox if there is no strong necessity for it. It is quite easy to damage seals or other parts during incorrect disassembling and reassembling. Allow the manufacturer or “Air Trikes” to do it if necessary.

Recommended propellers for Suzuki-GEO engines with SPG-2:

Engine

 Reduction Ratio

KOOLprop model

G10 carb and TBI

2.34

63”

G10 carb and TBI

2.5

63” 67”

G10 TBI “Sport”

2.5

67” 69”Light

G10 Turbo

2.34

67”

G10 Turbo

2.5

69”Light

G13 BA

2.34-2.5

67” 69”Light

G13 BB

2.34-2.5

69” Heavy

G13 GTI

2.34-2.5

69” Heavy   73”

.

SPG-2 with bellhousings for Suzuki and Subaru

SPG-2 disassembled, special order gearbox with Rotax 912 hub assembled.

Gearbox installation (mechanical part of the conversion)

Main steps:

Flexpate “sandwich” and coupler installation

 

Parts used for single flexplate installation (in order as they go)

 

Machined standard flywheel or aluminum custom made one can be used as well.

Bellhousing installation (bolts can be used instead of studs)

Gearbox and damper housing bolted together

Damper installation

Next step – internal and external dimension chain verification.  I recommend trying to install the gearbox on the bellhousing to estimate the dimension between  the coupler and the rubber damper. It has to be 0 +/- 1mm (recommended 0 +/- 0.5mm)

If it is more, thin spacers between the damper and the gearbox triangle have to be installed, but not more than 4mm.  If it is less (gap between bellhousing and damper housing more than 1mm), I recommend to remove the steel crank coupler spacer.  When the dimension between  the coupler and the rubber damper is OK, torque stud nuts (or bolts)

14mm special wrench - good help!

And how we use it to install 3 other damper bolts. Torque them properly, don’t forget Locktite!

Then starter, and we are done!

As you can see – nothing difficult. All mechanical part of the conversion could be done for about half a day. The same way it can be installed to Suzuki G13, Subaru, Honda, Nissan engines.

Available options:

Canister-type muffler

1)Set of 3 light aluminum hard anodized pulleys. The alternator pulley is the same diameter as other pulleys

2) Light alternator with installation bracket. About 2lb lighter than the lightest standard GEO alternator with its bracket.

Motormount L-bars (2, each side) with 6 Barry-mounts.

Other options, the same as ready-to-install engines are available.

If you have any questions - contact Air Trikes Enterprises. E-mail: info@airtrikes.net  Phone number: (514) 685-2656  Website www.airtrikes.net