Prop question !

Is anyone interested to join a venture to start producing compressed aviation grade wood based products ? I have so far been able to press 1430 kg/m3 density composite with high grade epoxy and well engineered high compression press. This stuff is bullet proof as well…with similar to kevlar thickness. I bet some funds could be collected for this. Anyone ?

Pregwood was one brand the props were made out of in the States…that stuff does not float…it has spedific density of 1,3…much heavier than water.

Haha best comment i’ve read yet!!

Its for if they crash into the sea they can just use 2 of the wooden props as oars when theyre on a little dinghy 🙁

I remember the ‘109 ‘Black 6’ having a wooden replacement prop fitted and shock loading was the reason given.

Although I wouldn’t really like to comment on the ‘shock-loading’ argument it must be remembered, when talking about the restoration of mass-produced wartime aircraft, that the circumstances of manufacture aren’t the same.

For mass-producing tens of thousands of propeller blades the most cost-effective method, for example drop-forging in aluminium, may be quite different from the most cost-effective method for manufacturing, say, a single set of blades.

Video HOW PROPELLERS ARE MADE.

https://youtu.be/pADELrIBYX0

Duramold and Weldwood were invented in the thirdies why not make that stuff today with high grade epoxy as a bonding material ? Or was the aviation tycoon Howard Hughes last to try it with urea based glues !? Could Lipps props be made lighter with that wood composite reaching 94% prop efficiency?

Thanks for the answers, much preciated.

Everydays a school day! Zzzzzzzzzzzzzzzzz!

I remember the ‘109 ‘Black 6’ having a wooden replacement prop fitted and shock loading was the reason given.

Very interesting loading conditions for a material.

As an educated guess I’d say that the bending loading, due to the thrust against the airstream, was relatively small compared to the tension loading due to centrifugal force (a force which, for a given RPM, will depend entirely on the mass of the blade).

Given also that the physical limitations on the shape of the blade, long and predominantly thin, call for a material that is light and relatively ‘stiff’ (as opposed to being particularly ‘strong’)…

…that screams ‘wood’ to me.

Metal or wood, if you have a prop strike, engine is treated for shock loading. Pros and cons for both materials however! I’d say the material was the biggest factor in those days – metal was at a premium!

Also, I think with a wooden prop the engine is less likely to suffer shock loading if the aircraft has a prang

Seriously, why not?

Among the reasons are that the propeller companies in business had spent a long time at it, and were rather good at producing excellent designs. Manufacturing similar shapes in metal would mean stepping into new areas of technology that offered no immediate performance advantages. In this context it was worth noting that when Rotol was established as a new propeller producer it began with metal (magnesium) props but switched to wooden ones. Wooden props were lighter than metal ones, something generally considered a good idea. As one rare exception, when arrester hooks were added to Hurricanes the heavier metal prop was required to keep the cg adequately forward. There’s the practical effect that when an aircraft belly-lands, a wooden propellor splinters whereas a metal propellor carried loads back into the engine, resulting in the need for an engine change, not just a propeller change. Notable on Seafires, where an awkward landing could see the propeller “pecking” the metal deck, thus requiring much more time in the hangar.

How come so many fighters had wooden props ?

Because Aluminium was in short supply and wood is a good vibration damper