nedmin
Well-Known Member
Did anyone understand from the article how this worked,its as clear as mud to me! just like the quality of the photo,s /forums/images/graemlins/confused.gif
Yellowfin VSD
- Thread starter nedmin
- Start date
Geoffs
Well-Known Member
I'm glad you've said that, I thought it was just me being thick /forums/images/graemlins/tongue.gif
powerskipper
Well-Known Member
I have had a long chat with the guy at the show about it.
short version.
here is the drive system,
it is a 1/3 or 1/2 in the water, on the back transom. it is managed by a GPS and some levelling system [can't remember what he called it], that after all the dimensions of the boat are input to the control thingy, works out the way the legs/balls need to turn or twist to make the boat go that way, it means bow thrusters and trim tabs are redundant, it is all controlled by a joystick that will hold the position when pressure is off, [like throttles] this has 2 settings, I believe one for marinas and one for open water. it can be retrofitted to shafts or out drive leg boats.
does that make sense.
short version.
here is the drive system,
it is a 1/3 or 1/2 in the water, on the back transom. it is managed by a GPS and some levelling system [can't remember what he called it], that after all the dimensions of the boat are input to the control thingy, works out the way the legs/balls need to turn or twist to make the boat go that way, it means bow thrusters and trim tabs are redundant, it is all controlled by a joystick that will hold the position when pressure is off, [like throttles] this has 2 settings, I believe one for marinas and one for open water. it can be retrofitted to shafts or out drive leg boats.
does that make sense.
smileygirl
Well-Known Member
I think the idea is to be able to change the pitch of the propellor blades from 0 degree (ie in line with the transom) to 90 degrees (inline with the boats keel. )
Obviously at 0 degrees blades go round nothing happens
at 90 degrees boat will go sideways
at @ 45 degrees the boat will go either forwards or backwards.
the 2 prop drives will always be running in the opposite direction to each other. so when boat is going forwards it will run true rather than having serious prop walk issues.
by having two variable pitch props I think you can make the boat do the IPS/zeus trick. I don't think you could control it as a human but using good old electronics the pitch of each drive unit can be continually varied several times a second. Without this level of control the boat would go round in circles. With it and a joystick , human forwards backwards left right is straightforward to convert into continual pitch tweaking to create the desired direction of movement.
I strongly suspect there is some clever technology to do with the size and shape of the blade surface (hence no clear pictures) They won't look like traditional continual curving or cupped prop blades. They article mentions stainless blades coated with titanium. titanium coating I believe is extremely hard - surface pressures at blade tips could be very high and cavitation would be an issue and wreck bronze or similar. I think the titanium would resist the cavitation damage
I really like the idea. wonder if they could do a conversion kit for a sealine 410 ,shift the water tank out of the way, dump the rudders etc. 50 knts 5 miles per gallon , where is the jig saw....
Obviously at 0 degrees blades go round nothing happens
at 90 degrees boat will go sideways
at @ 45 degrees the boat will go either forwards or backwards.
the 2 prop drives will always be running in the opposite direction to each other. so when boat is going forwards it will run true rather than having serious prop walk issues.
by having two variable pitch props I think you can make the boat do the IPS/zeus trick. I don't think you could control it as a human but using good old electronics the pitch of each drive unit can be continually varied several times a second. Without this level of control the boat would go round in circles. With it and a joystick , human forwards backwards left right is straightforward to convert into continual pitch tweaking to create the desired direction of movement.
I strongly suspect there is some clever technology to do with the size and shape of the blade surface (hence no clear pictures) They won't look like traditional continual curving or cupped prop blades. They article mentions stainless blades coated with titanium. titanium coating I believe is extremely hard - surface pressures at blade tips could be very high and cavitation would be an issue and wreck bronze or similar. I think the titanium would resist the cavitation damage
I really like the idea. wonder if they could do a conversion kit for a sealine 410 ,shift the water tank out of the way, dump the rudders etc. 50 knts 5 miles per gallon , where is the jig saw....
smileygirl
Well-Known Member
thanks for that, Julie
could not go to show was fascinated to find out what they had done. Looks like the blades might be gimballed like a helicopter. The angle of attack and the pitch of the blades changes as the prop rotates. The jist of it I think is still the same.
could not go to show was fascinated to find out what they had done. Looks like the blades might be gimballed like a helicopter. The angle of attack and the pitch of the blades changes as the prop rotates. The jist of it I think is still the same.
Solitaire
Well-Known Member
Will let you all know shortly, Jon and I have been invited to test drive the boats fitted with the system.
nedmin
Well-Known Member
Thanks everyone! Why couldnt MBM show a photo like that, and also get someone with mechanical knowledge to explain it! The guy that wrote the article has probably got a degree in social studies!
MarkHB
New Member
Variable pitch surface drive then.
B175Chris
Well-Known Member
Anyone know how much it is?
Can't believe I missed it at the show, vids on the web look really interesting /forums/images/graemlins/laugh.gif
Chris
Can't believe I missed it at the show, vids on the web look really interesting /forums/images/graemlins/laugh.gif
Chris
oceanfroggie
Well-Known Member
No, it was not explained well and no photos. Unlike like those above. It's just another glorified variable pitch prop system and just as vunerable to hits as IPS
SimonC
Well-Known Member
All right, take it easy on the insults! /forums/images/graemlins/shocked.gif
The design of the fins was top secret and we could not print a photo until the official unveiling at Southampton. They were very hush-hush about it but we wanted to get something in as we'd had a go and wanted to tell you about it straight away!
Sorry if the article wasn't clear - it's quite hard to explain a whole new concept in a short article. But yes, the fins are computer managed and can change their angle and pitch to maximise thrust/efficiency, to level the boat like trim tabs, to turn the boat in an IPS/joystick way, and to hold the boat in a stationary position if required.
It look as though the drive will be partnered with Caterpillar and Volkswagen, and is expected to go into production "around the middle of next year".
Watch this space!
The design of the fins was top secret and we could not print a photo until the official unveiling at Southampton. They were very hush-hush about it but we wanted to get something in as we'd had a go and wanted to tell you about it straight away!
Sorry if the article wasn't clear - it's quite hard to explain a whole new concept in a short article. But yes, the fins are computer managed and can change their angle and pitch to maximise thrust/efficiency, to level the boat like trim tabs, to turn the boat in an IPS/joystick way, and to hold the boat in a stationary position if required.
It look as though the drive will be partnered with Caterpillar and Volkswagen, and is expected to go into production "around the middle of next year".
Watch this space!
oceanfroggie
Well-Known Member
Thanks Simon. It's just the old cliche 'a picture tells a thousand words'. Love the mag btw.