New Propeller Innovation: Looking for Comment/Interested Parties

These designs only allow diameter variation within the recommended upper and lower limits for any propeller for a given engine.

In effect they would allow the operator to get the performance delivered by the smallest prop their engine could use, to obtain higher cruise- without sacrificing low speed performance (i.e. acceleration) that would normally be the penalty of a smaller prop.

Put it another way, you get the acceleration of a big prop without losing the high speed performance of a smaller one.

 

You're correct that the hydrodynamics of the inner blade/hub area are a big mystery. We really don't know how the large gap that opens up at larger dynamics affects cavitation and vibration, not to mention blade flex and stress. We really need other people with backgrounds in those areas.

The centrifugal forces you mention are indeed very large but the whole basis of the innovation is that the blade is CAPTIVE at all diameters. No matter what diameter, rpm or pitch setting the blade is fully retained and able to be infinitely controlled by the pitch and diameter control mechanisms.

A lot of people have been searching for this for several decades and we think we have achieved it in a simple and elegant way.

Thanks for your comments

 

How do you achieve the ability to smoothly withdraw the diameter while it is spinning, at various rpms? The "centrifugal" force can vary by a thousand pounds with just 500 rpm variation. So simply using a spring to balance the forces would not work.

 

I'm afraid that's the very innovation we're patenting and the problem that people have been trying to solve for decades i.e. totally captive blades that resist centrifugal forces yet allow full control of diameter by direct mechanical linkage.

There are no springs. The blades are fully captive at all diameters.
The diameter control/blade retention is fully compatible with pitch control as well.

Its the same problem as variable radius cranks pose.

We would reveal it under a confidentiality agreement only.

Thanks for your comments.

 

Looking at past posts it's clear we didn't explain well enough what our innovations do.

Some people think it's just another variable pitch propeller (it's not).

Some think the diameter change and blade retention is by springs (it's not).

We updated our website to explain why the problem we've solved is hard and why our solutions are unique.

It's akin to having a bicycle pedal that can move to any length of the crank, under full load and with total control, totally captive at any radius via direct mechanical links, without springs, slip or friction retention.

It's even harder in a prop where force is applied via a central shaft and the blades want to depart under centrifugal force.

Look at www.ndjen.com for further explanation.

regards

 

Um, someone said that springs would not work .

 

Agreed, but some said it was the same as the torqueshift device which DOES use springs.