User:SvingenB/sandbox

Summary

This article tries to compare and define various available and potentially available VW engine conversion and VW based engines used in light airplanes today. This is done on the basis of numbers and facts. It is a simple compilation of data for further study and reference.

History

A short historical background is needed to put things into perspective. VW engines has since just after the second world war been used in light aircraft. The history is different in different parts of the world, and the "industry" developed around these engines has done so surprisingly independent from each other, and with different focus. All types of VW boxer engines has been used as aircraft engines, not just the beetle engine.

France

This is where the earliest utilization of VW engines in aircraft started. This started just after the second world war. The countryside in France were then literally littered with abandoned Kubelwagen, the German version of the Jeep. The Kubelwagen used a VW boxer engine, the Beetle engine. French aviation enthusiasts simply took these engines off the Kubelwagen, mounted propellers on them and used them in all kinds of small airplanes. Several small companies grew up from these early adopters, notably JPX, Hapi and fff with very advanced conversions. Today all production of VW aircraft engines seems to have stopped completely. The engines from France are all based on the Type 1 VW engine (beetle engine).

Germany

In Germany this development started much later than in France. The first engines started to be available in the mid 1970s. The use of these engines in Germany was first and foremost in certified motorgliders, hence the engines also was certified accordingly. Two notable companies grew up, Limbach and Sauer. Limbach has produced more than 6000 VW based engines, while Sauer has close to 1000. The engines used as base was the Type 1 engine and the much more solid Wasserboxer. The engines from Sauer and Limbach represent the most advanced and most powerfull VW conversions available. Since all parts are custom made for aviation use, they are more correctly described as VW based rather than a VW conversion. Together about 7000 engines have been produced and the production is still going. Sauer has been able to convert the production to substantially less costly non-certified units for the ultralight market, engines able to compete even with Rotax 912 on price/performance. Nevertheless, it is definitely correct to say that the peek of production and sales from both companies lies in the past.

Another notably producer is Grob. Their engines were used in their Grob G109 motorglider. Although low in volume and the engine were not available as a stand alone product, Grob is the sole example of using the Type 4 VW engine as an aircraft engine.

USA

Rather oddly at first thought, this is were the VW conversion business is flourishing today. It is hard to point at one specific reason here, but where the companies like Limbach, Sauer and JPX focused on high tech, certified and therefore very costly production, the American companies adopted a down to earth grass-root approach. This grass-root approach often (but not always), consists of selling engine kits rather than complete engines. These kits typically use off the shelf automotive parts for the core engine parts (casing, cylinders, piston etc) instead of all custom made as the Sauers and Limbachs. Custom made parts are only used where needed (crank shaft, cam shaft, ignition, carburetor typically). Whatever they may lack in refinement and horsepower, they make up for in availability and low cost. Were the German engines were part of the very high tech, and very German and expensive, gliding industry, the American engines were a major part of the grass-root experimental aircraft movement (EAA) growing up from the late 1950s. All the available American engines are Type 1 based, and are experimental engines.

For instance, a non certified Sauer S 2200 UL cost twice as much as an AeroVee, and a certified Limbach L 2000 cost twice as much as a non certified Sauer S 2100 UL. All these 3 engines have similar performance and all are type 1 VW conversions.

Brazil

Brazil has a long tradition of manufacturing VW engines and cars. Lately a new VW based engine have been seen in the news and at stands. It is the Motorav. This engine appears to be have a redesigned casing and a redesigned cylinder head, but is basically a VW engine (the pictures of their engines and the drawings does not appears to be consistent though). Three engines are on their list. If they will be available in the USA and Europe, or at all, remains to be seen.

VW Engine Types

Type 1

The Type 1 series of engines are the most widely used engine for VW aircraft conversion. This engine is simple and light.

Wasserboxer

The Wasserboxer is a further development of the Type 1 engine. The Wasserboxer was used on late VW vans. The casing of the Waserboxer is much stronger built than the Type 1 since it was designed for 112 HP and 2100cc displacement, not 40 HP and 1200cc displacement as the Type 1. Still, it is of same length and only about 7 kg heavier. The Wasserboxer is used on all larger Limbach and Sauer engines.

Type 4

The Type 4 engine is a different engine altogether from the Type 1, larger and heavier, yet very similar in appearance. It was air cooled. It was used on the 411 and 412 series of VW cars. Only Grob is known to have used this engine as an aircraft engine as the Grob 2500 used in the Grob G109 motorglider. Even though not available today by any manufacturer, it is included below since many motorgliders have this engine installed today.

Characteristics

The specs are taken from the manufacturers web sites.

• AeroVee 2.1 is the kit engine from Aeroconversions
• GP is the kit engines from Great Plains
• Grob 2500 is the Grob Aircraft VW type 4 conversion
• Hu is the Hummel engine
• JPX is the JPX engines
• L is the Limbach engines
• M is the Motorav engines
• R-2300 is the Revmaster R-2300 engine
• S is the Sauer engines
• Orange is obsolete engines (not sold today, but in use), and green is engines in development.

Overall Specs

Engine name	Max power (HP)	at RPM	Cont. power (HP)	at RPM	Weight (kg)	Crankcase	Cooling	Bore (mm)	Stroke (mm)	Displacement (cc)
AeroVee 2.1	80	3400	80	3400	73	Type 1	Air	92	82	2180
GP 1600	55	3600	50	3400	72	Type 1	Air	85.5	69	1585
GP 1835	65	3600	60	3400	74	Type 1	Air	92	69	1835
GP 1915	69	3600	65	3400	74	Type 1	Air	94	69	1915
GP 2180	76	3600	70	3400	75	Type 1	Air	92	82	2180
GP 2276	80	3600	76	3400	75	Type 1	Air	94	82	2276
Grob 2500	95	3400	87	3000	95	Type 4	Air	100	78	2450
Hu 50 HP	55	3600	50	3400	73	Type 1	Air	85.5	69	1585
Hu 60 HP	65	3600	60	3400	75	Type 1	Air	92	69	1835
Hu 76 HP	76	3600	70	3400	76	Type 1	Air	92	82	2180
Hu 85 HP	85	3600	80	3400	76	Type 1	Air	94	86	2387
JPX 4T60	65	3200	61	3410	72	Type 1	Air	93	75.4	2049
JPX 4TX75	82	3000	76	2900	78	JPX	Air	95	82	2325
JPX 4TX90	90	3000	82	2900	74	JPX	Air	95	88	2495
L 1700 E0	68	3600	60	3200	73	Type 1	Air	88	69	1679
L 2000 E0	80	3400	70	3000	74	Type 1	Air	90	78,4	1995
L 2000 EB	80	3400	70	3000	76.5	Wasserboxer	Air	90	78,4	1995
L 2400 EB	87	3200	84.5	3000	82	Wasserboxer	Air	97	82	2424
L 2400 DFi	100	3000	95	2800	76	Wasserboxer	Water	97	82	2424
L 2400 DT	129	3000	118	2700	86	Wasserboxer	Water	97	82	2424
L 2400 DT.X	158	3000	145	2700	86	Wasserboxer	Water	97	82	2424
M 2.4 R	85	2900	80	2700	85	Motorav	Air	94	88	2443
M 2.6 R	90	2900	85	2700	86	Motorav	Air	94	94	2609
M 2.8 R	100	2900	95	2700	84	Motorav	Air	98	94	2836
R-2300	85	3200	80	3000	77	Type 1	Air	94	84	2332
R-3000	115	3400	110	3200	93	Revmaster	Air	102.4	90	1962
S 1800 UL	68	3200	65	3000	63	Type 1	Air	92	69	2123
S 1900 UL	75	3200	72	3000	64	Type 1	Air	94	69	1915
S 2200 UL	85	3000	80	2700	66	Type 1	Air	92	84	2234
S 2400 UL Al	100	3500	90	3000	75	Wasserboxer	Air	94	84	2332
S 2400 UL Mg	100	3500	90	3000	68	Type 1	Air	94	84	2332
S 2100 ULT	110	3000	100	2800	76	Wasserboxer	Air	90.5	84	2161
S 2500	94	3000	82	2700	77	Wasserboxer	Air	97	84	2483
S 2700 UL	105	3000	93	2700	75	Wasserboxer	Air	97	90	2660

Bore and Stroke

Since the VW based engines all have the same casing, more or less, the only difference is bore and stroke. It will therefore be very easy to compare the different engines by plotting them into a table with stroke along the x-axis and bore along the y-axis. The reference engines are also direct drive flat four, so the comparison will also be valid for them. This is plotted along with the corresponding bore/stroke ratio.

Stroke along x-axis, bore along y-axis, mm and bore/stroke

Bore	69	75.4	78	78.4	82	84	86	88	90	94
85.5	1.24 GP1600 Hu50HP
88	1.28 L1700
90				1.15 L2000
90.5						1.08 S2100ULT
92	1.33 S1800UL GP1835 Hu60HP				1.12 AeroVee GP2180 Hu76HP	1.10 S2200UL
93		1.23 JPX4T60
94	1.36 S1900UL GP1915				1.15 GP2276	1.12 S2400UL R-2300	1.09 Hu85HP	1.07 M2.4R		1.00 M2.6R
95					1.16 JPX4TX75			1.08 JPX4TX90
97					1.18 L2400	1.15 S2500			1.08 S2700UL
98										1.04 M2.8R
100			1.28 Grob2500
102.4									1.14 R-3000