such as the French le Rhone. They were light and kept cool while taxying.

1. Colossal centrifugal force, making the aircraft flick into very tight turns, only controllable by an expert which gave tremendous manoeverability
2. Lubrication: at a time when the Germans were running out of caster oil.
3. limited horsepower, 90-110 HP
4. Limited "bite" from the prop, the prop had to be short enough for the aircraft to taxi tail up and miss the ground.

But at the end of the war, the Germans designed this beauty

The Siemens- Shuckert DIV. This was rotary engined, and turned at 1800 revs, difference being

an intermediate gear made the prop turn in the OPPOSITE direction to the cylinders. Also a rear gear made the

prop rotate at half engine speed, allowing 4 blades to get a good grip on the airflow. Note streamlined spinner

and also huge cooling slot under cowling.

 To me, that engine looks much more meaty (160 HP)

than the Le Rhone above.

The Siemans Halke engine could offer a rate of climb of 24,000 feet in 36 mins.

It outperformed the Fokker DVII and was produced after WW1 for Switzerland