08-23-2026, 02:48 PM
the rotorway design works, just well enough. it was designed for simplicity, which often is the best route.
sadly we're at the edge of our performance envelope.
the biggest issue i see with the original rotorway design is the constant speed, fixed pitch fan. while simple and light, its inefficient. even old classic automotive cars/trucks used a viscous clutch fan to lock up the fan at high temps biting more are, and loosen up in cool conditions conserving that power and not wasting it on moving unnecessary cooling air. the rotorway fan just constantly pushes air, idle, 100%, hot, cold, its just constant.
thats the next issue, pushes air, thats another thing we can learn looking at those automotive classic cars they are all configured for pulling air through the radiator, not pushing. and when cars changed to electric fans they could have moved them to pushers to conserve more space, but they didnt because its significantly less efficient.
now lets talk about just cutting holes in the body panel to open the cowlings for more airflow, while this may work in the hover, you have to be careful in forward flight. the area you talk about right above the fan on the upper body is actually a lower pressure area, if this area is lower pressure than the bottom of the radiator it could actually fight against the flow of the fan. thats where the scoops come in, we need to have the opening in a high pressure area which we create with the scoops, and direct it to the radiator which sits at a natural low pressure area.
the electric water pump does nothing to help cooling except for at shutdown by allowing the engine to idle and the flow remains 100%. its also a complicated coolant circuit and it allows priming/bleeding convenience. but you lose simplicity of a belt driven system to one that needs switches, relays, and more current produced.
all improvements to be done at your own risk, and tested thoroughly with your results and procedures written into your checklists and aircrafts unique POH. if you already have your airworthiness cert the FSDO should be notified and modification noted/inspected by the FAA again. i chose to do mine now because of this.
long reply. sorry Tim.
sadly we're at the edge of our performance envelope.
the biggest issue i see with the original rotorway design is the constant speed, fixed pitch fan. while simple and light, its inefficient. even old classic automotive cars/trucks used a viscous clutch fan to lock up the fan at high temps biting more are, and loosen up in cool conditions conserving that power and not wasting it on moving unnecessary cooling air. the rotorway fan just constantly pushes air, idle, 100%, hot, cold, its just constant.
thats the next issue, pushes air, thats another thing we can learn looking at those automotive classic cars they are all configured for pulling air through the radiator, not pushing. and when cars changed to electric fans they could have moved them to pushers to conserve more space, but they didnt because its significantly less efficient.
now lets talk about just cutting holes in the body panel to open the cowlings for more airflow, while this may work in the hover, you have to be careful in forward flight. the area you talk about right above the fan on the upper body is actually a lower pressure area, if this area is lower pressure than the bottom of the radiator it could actually fight against the flow of the fan. thats where the scoops come in, we need to have the opening in a high pressure area which we create with the scoops, and direct it to the radiator which sits at a natural low pressure area.
the electric water pump does nothing to help cooling except for at shutdown by allowing the engine to idle and the flow remains 100%. its also a complicated coolant circuit and it allows priming/bleeding convenience. but you lose simplicity of a belt driven system to one that needs switches, relays, and more current produced.
all improvements to be done at your own risk, and tested thoroughly with your results and procedures written into your checklists and aircrafts unique POH. if you already have your airworthiness cert the FSDO should be notified and modification noted/inspected by the FAA again. i chose to do mine now because of this.
long reply. sorry Tim.