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Hoveroz - n/a
4-Feb-08, 06:08 AM
Can anybody shed any light on using a hydraulic drive for the lift fan. Cheers, Mark Australia

team black - n/a
4-Feb-08, 07:35 AM
Kevin Foster's your man- no doubt he'll respond, but you could pm him on kevinf

kevinf - n/a
4-Feb-08, 10:54 AM
Contact made, and information passed over. Thanks for the reference Ewan.



Kevin

hover t - n/a
4-Feb-08, 01:30 PM
Kevin

can you send that info to me as well please, It could be a option for my hover



Thanks

Trev

kevinf - n/a
4-Feb-08, 03:34 PM
Hi Trev



If you PM your direct email address to me, I'll send a copy to you - it's a 2MB file.



Kevin

machineage - n/a
5-Feb-08, 01:24 PM
My Hover uses a Hydraulic lift system - it's a closed loop hydrostatic drive utilising a variable displacement pump (with charge pump) and fixed displacement motor. More info on my site if anyone's interested. It is generally thought that the Mustang is the smallest size Hovercraft for which the system becomes viable...



Chris Simpson.

kevinf - n/a
8-Feb-08, 06:25 PM
Chris



We use a very simple closed loop system with fixed capacity commercial gear pump and motor (about 85 each), with an oil cooler in the return leg. Total oil capacity of the whole system is about 1.5 litres tops. This runs the lift in our single seat F2 and F3 racers. Unsophisticated and foolproof. Cost-wise it compares favourably with a shaft drive installation. The great thing about the system is that it does not need the careful alignment of a shaft-drive system which means that it is also quick and easy to install. It is virtually maintenance free, and the lift fan orientation can be whatever you want instead of being dictated by the right-angle gearbox.



Kevin

machineage - n/a
9-Feb-08, 01:58 AM
Hi Kevin



I'm glad there are people using fluid power for small Hovers as hydraulics do offer some advantages as you point out http://hovercraft.org.uk/images/icons/smiley_icons/icon_smile.gif

I think hydraulics can also be well suited to the environment of a Hovercraft. Fluid power is a fascinating subject (if you are that way inclined!) and something I am learning about all of the time...



I was referring to the system in the Mustang when mentioning viability which I think? is the smallest craft built commercially which uses a variable hydrostatic transmission before factors such as cost - weight and complexity rule it out in comparison to other systems. Times move on though and technology improves (and gets cheaper!) http://hovercraft.org.uk/images/icons/smiley_icons/icon_smile.gif



The Mustang uses an Eaton variable (positive) displacement piston pump and an Eaton fixed (positive) displacement piston motor. These have very good efficiancy but are much more expensive than gear pumps / motors. Another requirement for these components is a very clean system as contaminents in the oil can reduce the component lifespan and efficiancy - so a filter is incorporated to maintain oil quality. A charge pump is also incorporated to pressurize and maintain the main loop capacity - and prevent main pump cavitation.



The system has the ability to provide every power share situation from full thrust with no lift through to full lift with no thrust. It is also extremely smooth operationally with pretty much zero vibration from either the pump / motor or fan. The Mustang also makes use of the hydraulic power by way of servo operated elevators and rudders - and dual hydraulic fans for cooling.



All of this adds complexity and cost... The Mustang after all was an experiment in scaling down the systems used in the much larger Airlift Surveyor and Pioneer craft. It was a technical success - but proved too costly in terms of manufacturing for this class of Hovercraft when compared to other systems. Probably why I love it http://hovercraft.org.uk/images/icons/smiley_icons/icon_surprised.gif



Chris