Fings wot broke

[maybelateron]

A good illustration that. So is that why the big FO chippers like Heizohack Bandit etc are drum type, I guess?

[Mick Dempsey]

Great vid and explanation. 
TBH the thing you’re highlighting doesn’t seem to be an issue. 
Be interested what real engineers make if it. 

[AHPP]

Yeah, disc ones obviously work but if you had poor/undersized materials, poor/undersized components or just needed the best possible, why wouldn't you go drum. You could put different flywheels and pulleys on the outboard end of the axles for different engines without changing anything inside the chipping chamber.

Edited June 29 by AHPP

[AHPP]

1 hour ago, AHPP said:

 

 

 

Plus the drum is probably way stiffer than my model because it'll be a big monocoque running right up to the bearings at each end. Probably only half an inch of axle in free air to have a spacer or very light thrust bearing on.

Edited June 29 by AHPP

[Jase hutch]

True enough , flywheels flex in use , that's why we have a blade to shearbar gap to allow for this flex but even on 8" chippers this only needs to be 2.5mm. Regarding putting different pulleys and engines on , why would you need to change anything inside the chamber with a flywheel set up ?

[AHPP]

13 minutes ago, Jase hutch said:

Regarding putting different pulleys and engines on , why would you need to change anything inside the chamber with a flywheel set up ?

 

Because the flywheel that keeps the engine at optimal revs etc is also the chipping disc. Change its diameter or thickness and you have to change the housing to keep air pushing/pulling properly. 

[AHPP]

I do get that my criticisms are largely academic. Ten thousand disc woodchippers are going to work absolutely fine at ten o'clock tomorrow morning.

[Mick Dempsey]

I guess weight and ease of manufacture is a factor as well. 
 

[AHPP]

https://vermeeruk.co.uk/blog/drum-wood-chippers-vs-disc-wood-chippers-which-is-better-

 

[PeteB]

I did a power point presentation to explain all the different types of chipper and their pros and cons. A drum is a good way to get a bigger capacity without a wide machine as a disc is over twice the width of the chipper capacity. A disc style machine has a decent amount of centrifugal forces helping to keep it going and can easily produced the puff to blow woodchips and are easy to produce and assembly where a drum may need more assembly/fabrication time and have the need for an extra blow system to blow the chips. The majority of hand fed Chippers are the disc style and yes, the bearings let go eventually, some may consider this as planned obsolescence but by the time they got a rumble on, they have done a few shifts!