Engine Balancing
Disassembly of a turbine is a task that a ten year old could accomplish. Reassembly and re balancing the unit afterwards is a much different story.
We pride ourselves in delivering engines that work and engines that stay together. We have the right tools and the best resources to get the job done fast and reliably.
RPM Versus Thrust - Turbine manufacturers long discovered that increasing RPM could increase output exponentially with increases in RPM. The problem is that the stresses on the unit are also increased exponentially. The original microturbines were generally set to output 70% of whatever output was deemed to be on the brink of failure. Now it appears that the units are pushed practically to the level of break down.
Increased rotating mass and reaching design max for a wheel - Have you ever looked at how much calibration and balancing goes into a race car or race bike engine? Balance is crucial as the output is pushed and as the RPMs are increased.
What affects balance?- Hovering - All the dirt you see being pushed outward is going right into the front of the engine.
- Flying off grass fields
- Look at the leading edge of the compressor blades. if you can see nicks,
the motor is out of balance.
- Look at the face of the blades. If they look burnished
the compressor is out of balance.
CRX maintains good balance for our customers. It is a trivial operation to touch up balance a turbine.... As compared to fixing one that blows a bearing and/or a wheel.
So what happens when an engine "blows up"? The cause is generally uncovered by a tear down of the engine. Studying the internal parts for clues of what occurred.
Front end issues or tail - The compressor and turbine wheel are coupled by the same shaft. The shaft rides on two bearings, fore and aft. The clearance in the tail between the turbine wheel and NGV (Nozzle Guide Vane) is set at about .3 mm side to side. The clearance in the nose is similar. If either the front or back start to wiggle due to excess bearing wear, the motor can blow up. If the issue occurs in the front, the compressor generally locks up on the diffuser and if this occurs in the tail, the turbine wheel contacts the NGV. Most guys have seen cases where a turbine loses blades from 12 - 3 o'clock.
Bearings - Every microturbine utilizes angular contact ceramic hybrid bearings. The best bearings available are GRW. They are rated at 300 degrees C. I tell guys all the time, if you overheat the tail, your engine is headed to hell in a hand basket, fastttt.
How do we tell if an engines has been overheated? Blue Black bearings. Blue Black stainless is indicative of 1300 degrees plus.
Question... Ask yourself, "How far could I go without oil in my vehicle. The
answer is in feet, not miles... same with a turbine. Overheat it and it is game
over...
A note about hovering - Hovering is cool, BUT, buy yourself a motor that puts out 30% more power than you need and you will be fine. If you run your engine at 100% all the time standing still, plan on repair or replacement of your engine in a shorter period of time..
Disassembly of a turbine is a task that a ten year old could accomplish. Reassembly and re balancing the unit afterwards is a much different story.
We pride ourselves in delivering engines that work and engines that stay together. We have the right tools and the best resources to get the job done fast and reliably.
RPM Versus Thrust - Turbine manufacturers long discovered that increasing RPM could increase output exponentially with increases in RPM. The problem is that the stresses on the unit are also increased exponentially. The original microturbines were generally set to output 70% of whatever output was deemed to be on the brink of failure. Now it appears that the units are pushed practically to the level of break down.
Increased rotating mass and reaching design max for a wheel - Have you ever looked at how much calibration and balancing goes into a race car or race bike engine? Balance is crucial as the output is pushed and as the RPMs are increased.
What affects balance?
- Hovering - All the dirt you see being pushed outward is going right into the front of the engine.
- Flying off grass fields
the motor is out of balance.
- Look at the face of the blades. If they look burnished
the compressor is out of balance.
CRX maintains good balance for our customers. It is a trivial operation to touch up balance a turbine.... As compared to fixing one that blows a bearing and/or a wheel.
So what happens when an engine "blows up"? The cause is generally uncovered by a tear down of the engine. Studying the internal parts for clues of what occurred.
Front end issues or tail - The compressor and turbine wheel are coupled by the same shaft. The shaft rides on two bearings, fore and aft. The clearance in the tail between the turbine wheel and NGV (Nozzle Guide Vane) is set at about .3 mm side to side. The clearance in the nose is similar. If either the front or back start to wiggle due to excess bearing wear, the motor can blow up. If the issue occurs in the front, the compressor generally locks up on the diffuser and if this occurs in the tail, the turbine wheel contacts the NGV. Most guys have seen cases where a turbine loses blades from 12 - 3 o'clock.
Bearings - Every microturbine utilizes angular contact ceramic hybrid bearings. The best bearings available are GRW. They are rated at 300 degrees C. I tell guys all the time, if you overheat the tail, your engine is headed to hell in a hand basket, fastttt.
How do we tell if an engines has been overheated? Blue Black bearings. Blue Black stainless is indicative of 1300 degrees plus.
Question... Ask yourself, "How far could I go without oil in my vehicle. The
answer is in feet, not miles... same with a turbine. Overheat it and it is game
over...
A note about hovering - Hovering is cool, BUT, buy yourself a motor that puts out 30% more power than you need and you will be fine. If you run your engine at 100% all the time standing still, plan on repair or replacement of your engine in a shorter period of time..