new volvo IPS drive for river dave

[spectras only]

http://www.ybw.com/auto/newsdesk/20041101132742mbynews.html

[Tom Brown]

I like it but I wonder how much vibration they'll take on with those two props swatting away a close distance from the hull. I would guess it will be significant.

[Wet Dream]

I would bet that they put a lot of R&D into this. If it were that bad, I don't think they would continue the project.

[spectras only]

http://www.ybw.com/auto/newsdesk/20041101132742mbynews.html
TTT for Dave :mix:
http://www3.telus.net/spectrasonly/Volvo_Penta_IPS_side.jpg

[UltraLucky]

I do not think that would work out too well on a trailerable boat or low water areas like the river.

[Mandelon]

Pretty wild. Seems optimally functional for big yachts, but not so much at the river....or on trailerable craft.
And I've always wondered, why not delete the shaft altogether and make it a belt drive. :rolleyes:

[spectras only]

And I've always wondered, why not delete the shaft altogether and make it a belt drive. :rolleyes:
Mande , what propulsion you prefer on a M/C ? Shaft drive or belt drive for longevity :idea: :D . J/K

[Mandelon]

Never had anything but a chain......
Wouldn't it work though?

[Kim Hanson]

I for one think the prop is in the wrong place and it's going to slow you down like that stuff with the 2 props out front.........( . )( . ).......... :confused:

[Angry Inch]

Not to bring up an old thread..... But, I was doing some consulting work for a guy last night that was talking about these. From his point of view, a yacht guy, they are god sent. For one, the motor mounts become soft, making for less vibration through the hull. Second, the drive shafts are completely removed, opening a ton of space. The handling is supposed to be out of this world at speed. And, when docking into a slip, the control is so good, that an experienced driver doesn't need to use the side boosters. :idea:

[RiverOtter]

I like it but I wonder how much vibration they'll take on with those two props swatting away a close distance from the hull. I would guess it will be significant.
The local Cruisers dealer told me it's smoothe as silk. Easier to dock and 20% faster and 20% better fuel ecomomy.

[spectras only]

I like this setup better . Like a cessna 177 , if one prop lets go you still have another to get you home :rollside:
This boat had 1500 HP :cool:
http://www3.telus.net/spectrasonly/front%20prop%20hydroplane.jpg

[RiverDave]

It's a proven fact that a prop on the front works better then one in the back.. (Incidentally HH posted this same thread up a looonnnggg time ago when volvo 1st announced that drive system)
As far as trailerable craft, I don't see where it would make any difference at all? Outdrive is still trimmable? (up and out of the way) That's like saying a v-drive is untrailerable or something?
The only reason the prop is in the back of all the outdrives currently, was way back in the day when Volvo designed it.. They designed it so that if you were to hit a submerged object (log etc..) the outdrive would kick up out of the way, the prop would sustain minimal damage, and you could still putt it home.. With today's performance boating, if I hit a log underwater, the last of my worries is if the prop survived.. I'd rather crunch a prop then trash an outdrive.
RD

[spectras only]

Dave , volvo didn't design the sterndrive ;) .
This guy did :idea:
http://www3.telus.net/spectrasonly/johnson%20sterndrive.jpg

[RiverDave]

Must be some distant relative.. and while he might have had my charming personallity and good looks, he certainly didn't have the brains in the family.. If he did the prop would be on the front.
(Incidentally, I read that volvo put the prop on the back for the reasons stated above.. merc spawned more or less off of Volvo so they just followed suit)
RD

[Sleek-Jet]

I like this setup better . Like a cessna 177 , if one prop lets go you still have another to get you home :rollside:
This boat had 1500 HP :cool:
http://www3.telus.net/spectrasonly/front%20prop%20hydroplane.jpg
That would be a Cessna 337... Mushmaster/MixMaster.... :D :D
http://www.hotboatpics.com/pics/data/500/1153cessnaground.jpg

[RiverDave]

I thought they were called "skymasters" ?
RD

[Sleek-Jet]

I thought they were called "skymasters" ?
RD
Well... offically... yes... :D

[Tom Brown]

It's a proven fact that a prop on the front works better then one in the back..
Not so fast, hangover boy.
I've been following all sorts of experimental aviation journals and it would seem that the benefits of a tractor configuration are not at all cut and dried. Hell... even ducted fans, once widely believe to be more efficient than open props, are being discovered to be less efficient in many situations. Read any 10~25 year old aerodynamics text. They will tell you that ducted fan efficiency over open propeller is a proven fact.
It takes a lot of data to back that sort of statement up. From what I understand, it's not proven at all.
I'm disputing the claim of fact, not the technology. From what I can tell, it's extremely difficult to prove this sort of conclusively and, every once in a while, someone comes along and un-proves it.
Personally, I doubt there are many gains to be had, one way or the other. My guess would be the tractor to be more efficient than the pusher but only by a negligible amount.

[RiverDave]

Tom, I'm not even going to get into this whole discussion again, becuase the last time it took about a week of my life.. So in short, think about it for more then 2 minutes, then come back and realize that I'm right and your wrong.
RD

[Sleek-Jet]

You're both wrong... it's blade design more than anything... :D

[Tom Brown]

The local Cruisers dealer told me it's smoothe as silk. Easier to dock and 20% faster and 20% better fuel ecomomy.
They must be using a tornado fuel miser. There's no way a tractor has a 20% advantage over a pusher. No way.

[RiverDave]

You're both wrong... it's blade design more than anything... :D
All things being equal the tractor is more efficient.
RD

[RiverDave]

They must be using a tornado fuel miser. There's no way a tractor has a 20% advantage over a pusher. No way.
Your right Tom.. it's all lies.. In an effort to upset the delicate canatard balance they put the props on the front for confusion reasons.
RD

[spectras only]

All things being equal the tractor is more efficient.
RD
Dave , I just came back from Oregon [ excellent time on the dunes ] and dropped by the Mcminville air museum .
I've looked at the spruce goose and tought ,if Hughes put the props on the trailing edge of the wings it might have made it up more than 70' in the air :idea: ;) :D

[RiverDave]

Dave , I just came back from Oregon [ excellent time on the dunes ] and dropped by the Mcminville air museum .
I've looked at the spruce goose and tought ,if Hughes put the props on the trailing edge of the wings it might have made it up more than 70' in the air :idea: ;) :D
I was under the impression that the goose was able to fly, but hughes only took it up once for a shake down run.. The proof of it flying exhonerated him from some congressional hearings with regards to him being accussed of embezzling funds from govt contracts.. Same thing with Mr. Tucker? Or so hollywood left me to believe that anyways? Being that the contract was cancelled for troop transport carriers there was no reason to ever take it up again?
rd

[Tom Brown]

Your right Tom.. it's all lies.. In an effort to upset the delicate canatard balance they put the props on the front for confusion reasons.
RD
Dave. If tractors were that much more efficient, there would be no pusher aircraft.... but there are. Some of the most efficient aircraft in the air are the Burt Rutan design based canards. Canard... LOL! :D
Read the research papers. Everyone has numbers to prove that their design is better than the other guy's design. Everyone.
Now there's just no way a tractor is 20% more efficient than a pusher. It ain't happening.
Remember the EFI module claims for the Merc drag outboards? Up to 30% more efficient. Up to means roughly zero. Sure, you can tune some of the adjustable ones to have better performance in some parts of the range but there just isn't 30% gain to be had. That's not realistic. If there was, we should sue Merc for their incompetence.
I believe this is the same situation. There's just not 20% to be gained by going pusher to tractor. Look at SO's picture. I'll bet that was taken around 1970. If that thing was a whopping success in the push/pull configuration, we'd all be running that configuration now.
Now calm down... I know push/pull is different from straight pull.
I'm not saying there are no gains to be had. There could be. If you look at the big shipyard designs of propulsion pods, they're all tractors. That's probably as good of an indication as any that tractor has an efficiency edge.
It still remains, however,..... if someone wants to claim 20% more efficient, they better prove it. Put 10 gallons in each design with identical engines/hulls (each with best possible effort setup and rigging) and lets see how fast and far they go. Until then, it's just an advertisers claim.
Back to you... Dave. :)

[Angry Inch]

Even if it really isn't going to save 30% on gas or increase power pu 30%, it's really hard to overlook this turn:
http://www.ybw.com/img/newsdesk/mby/mbynews/IPS_manoeuvre.jpg

[spectras only]

I was under the impression that the goose was able to fly, but hughes only took it up once for a shake down run.. The proof of it flying exhonerated him from some congressional hearings with regards to him being accussed of embezzling funds from govt contracts.. Same thing with Mr. Tucker?
rd .
HH just wanted to prove everybody wrong . He used 18 M of government founded [ actually taxpayers ] money and 7 M his own already . If the Goose could have sustained a longer flight he would have done it :p .

[Sleek-Jet]

Dave. If tractors were that much more efficient, there would be no pusher aircraft.... but there are. Some of the most efficient aircraft in the air are the Burt Rutan design based canards. Canard... LOL! :D
Read the research papers. Everyone has numbers to prove that their design is better than the other guy's design. Everyone.
Now there's just no way a tractor is 20% more efficient than a pusher. It ain't happening.
Remember the EFI module claims for the Merc drag outboards? Up to 30% more efficient. Up to means roughly zero. Sure, you can tune some of the adjustable ones to have better performance in some parts of the range but there just isn't 30% gain to be had. That's not realistic. If there was, we should sue Merc for their incompetence.
I believe this is the same situation. There's just not 20% to be gained by going pusher to tractor. Look at SO's picture. I'll bet that was taken around 1970. If that thing was a whopping success in the push/pull configuration, we'd all be running that configuration now.
Now calm down... I know push/pull is different from straight pull.
I'm not saying there are no gains to be had. There could be. If you look at the big shipyard designs of propulsion pods, they're all tractors. That's probably as good of an indication as any that tractor has an efficiency edge.
It still remains, however,..... if someone wants to claim 20% more efficient, they better prove it. Put 10 gallons in each design with identical engines/hulls (each with best possible effort setup and rigging) and lets see how fast and far they go. Until then, it's just an advertisers claim.
Back to you... Dave. :)
Yeah, but old BurtyBaby has given up on pusher designes due to.... wait for it....
... the inherent loss's in that design configuration.
Rutan hasn't designed a pusher in over a decade, and he's been quoted as saying if he had it to do over, he wouldn't have designed a pusher... ever. :D

[RiverDave]

Yeah, but old BurtyBaby has given up on pusher designes due to.... wait for it....
... the inherent loss's in that design configuration.
Rutan hasn't designed a pusher in over a decade, and he's been quoted as saying if he had it to do over, he wouldn't have designed a pusher... ever. :D
Well that pretty much says everything better then I could've..
Tom, I believe the ball is in your side of the court.. Advantage Tractor.
RD

[spectras only]

A I , you can do an even tighter turn with any twin engined boat :wink: . I can turn my rear propped s/d boat in its own axis . It's that simple :) . Wish I could do that with my V-drive cruiser :wink:

[Tom Brown]

Yeah, but old BurtyBaby has given up on pusher designes due to.... wait for it....
... the inherent loss's in that design configuration.
Rutan hasn't designed a pusher in over a decade, and he's been quoted as saying if he had it to do over, he wouldn't have designed a pusher... ever. :D
That is in complete opposition to everything I've ever read about Rutan. I've done a tone of reading on the guy, the designs, and his thoughts on it.
... so I'm quite confident that you're full of shit.
Rutan got out of selling plans because he was sued by the wife of a guy who bought a Rutan designed plane, got drunk, took his mistress up flying, and crashed. Rutan won the suit but it cost him over a half million dollars. That is exactly when he stopped selling aircraft plans. He still helps some others sell pusher plans but he doesn't want to have any liability so he won't allow anyone to use his name.
Didn't you follow any of the interviews Burt gave with regard to his brother's X-plane design? They used a Long-EZ as a test bed for their rocket motor. Rutan commented on the outstanding efficiency of the Long-EZ.
Why don't you follow my post with a list of airframes that can do 240 mph with a Lycoming O-540 in level flight? Go ahead. :)

[Sleek-Jet]

Stand by.... :D

[Sleek-Jet]

http://www.lancair-kits.com/IV_images/IV_1_lrg.jpg
This one will do it... and it seats 4 people.
http://www.harmonrocket.com/Feathererston/HarmonRocketII.jpg
These are that quick to... and it's a conventional configuration, and Bohanen is using one to break all sorts of reacord (see the Pushy Galore comment below)
The Glassair III were that fast, but no longer in "production"
Don't forget the Sweringen SX300 either... also very fast.
Cassuts were as fast as EZ's and Long EZ's on the same power. The only succesfull pusher configured shoe-string racer was "Pushy Galore" and it's been retired in favor of a tractor configuration.

[RiverDave]

Is that game set match?
I believe Sleek Jet has just "geeked" the pants off our local canatard.
RD

[spectras only]

Kinda liked the BD with a pusher myself ,fast little sucker :wink: http://www.bd5.com/expo2002.htm
The IMP below seems pretty efficient at 5 gal/hr , 200+ mph with only 100 HP .
http://www.mini-imp.com/news.htm

[Sleek-Jet]

And I never said Rutan isn't a genious... but he has stopped designing canards and pushers.

[HCS]

I like it but I wonder how much vibration they'll take on with those two props swatting away a close distance from the hull. I would guess it will be significant.
Reduced noise and vibration
Again, the Sealine S42 provided the perfect yardstick. It was not possible to measure noise accurately (too many excited journalists onboard gabbling away) but subjectively there was no doubt whatsoever; the IPS S42 was significantly quieter than its counterparts.
IPS makes things far quieter and noticeably smoother largely because the propulsion unit feeds thrust loads directly into the hull, allowing the use of much softer engine mounts. This is the same principle used by the highly effective Aquadrive coupling. Vibration damping is further enhanced because thrust is transmitted via two large-diameter rubber O-rings, which also provide the watertight seal between the IPS unit and the hull.

[Tom Brown]

I believe Sleek Jet has just "geeked" the pants off our local canatard.
RD
Dave, I think your objectivity is suspect on this issue.
A guy in our club has a Glassair III and it's demonstrates less efficiency than a Long-EZ. I don't know anything about the other two airframes.
The neat thing about these discussions is how adamant everyone is about how right they are. If you listen to guys like Paul Lamar argue with other guys who have doctorates, you'd think they both have absolutely conclusive proof that their ideas are right.
I'll post some more on this when I'm off the clock. I gots to work for a bit...

[Sleek-Jet]

And since we're kicking ol' Burt around here, let's give him some credit
The Long EZ/VariEze efficiency comes more from the airframe design than the propulsion choice (but I guess the propulsion choice comes from the airframe design.... I'm getting dizzy :D ). Now we're getting into "flat plate" area and such.
And while trying to find my famous "I wouldn't design a pusher again" quote, I ran accross this:
The net result of all of this is usually little or no measurable benefits from reducing airframe drag, but quite significant losses due to these other factors, for an overall net loss. Even the possibility of recovering swirl energy, as in the case of a contra-rotating propeller system, usually does not start to see measurable benefits until you get into the sorts of horsepowers typical of turboprops and very large piston engines. I used to be an engineer for a propeller company that happened to have more experience with pusher installations than probably anyone else in the business (Voyager was one of those). Our usual first reaction when someone approached us with a new pusher application was to try to talk them out of it.
There are a number of aircraft designers (including Rutan) who have at some time in their careers been a big proponent of pusher designs. In general, they are airplane designers, not propeller designers, and tend to overestimate the benefits to the airframe of a pusher arrangement while badly underestimating the detrimental effects on the prop. There is a tendency to think of props as these mystical devices that you just bolt to the engine to make thrust, with little thought given to the prop's own needs and idiosyncrasies. To really get a decent working relationship between a pusher prop and the airframe usually takes an incredible amount of work. Piaggio came up with one of the better pusher designs (from an aerodynamic standpoint) in their P-180 "Avante", but it took a huge amount of engineering effort including over 2000 very expensive hours in Boeing's wind tunnel to achieve it.
http://www.djaerotech.com/dj_askjd/dj_questions/push-pull.html

[RiverDave]

Dave, I think your objectivity is suspect on this issue.
As you should.. There's somebody that is apparently far more educated then me in the matter beating the bejeezus out of you.. Why would I interfere with that? I'm thinking about selling ring side tickets to it for crying out loud..
incidentally My thoughts are based on more common sense and real world experiences then off of other peoples theories and doctorates. ;)
RD

[Sleek-Jet]

There's somebody that is apparently far more educated then me in the matter beating the bejeezus out of you..
RD
All I did was stay at a Holiday Inn last night. :D :cool:

[Tom Brown]

And since we're kicking ol' Burt around here...
I'm sure I could find some experts who have differing opinions to your expert's opinion. I'm no airframe designer and I'm no propeller designer.
... but I can tell you this.... there is not a 20% benefit to a tractor configuration. We have two canards in our club and we have tons of tractors in our club. A few of the tractors are very slippery. Of course, both canards are very slippery. Not only are the canards not slower, they pretty much dominate.
I'm not at home so I don't have access to any documentation or any real comparisons.
Hey Dave and Sleek... why don't you two design a front mounted prop gear case for the Bravo? You could even use a bunch of Bravo components and just redesign the case and thrust bearing to get people 20% gains in performance and efficiency. Look at the money people are kicking out for drives these days. Think how much people would pay to be able to do 120 mph with a boat that could only do 100 mph with a standard pusher Bravo.
Surely you could make a ton of money off that kind of efficiency gain.
As for me, I think I'll remain skeptical until the facts are in. I remember... it was quite a while ago... a new design was brought forth with much hype and was going to revolutionize an industry but turned out to not be quite as good as promised. I learned from that experience all those years ago and tend to be more conservative these days.

[RiverDave]

I like your signiature Brown.. :D
RD

[Tom Brown]

I like your signiature Brown.. :D
RD
It's the best thing to come through ***boat in a long, long time. :cool:

[Sleek-Jet]

I'm sure I could find some experts who have differing opinions to your expert's opinion. I'm no airframe designer and I'm no propeller designer.
... but I can tell you this.... there is not a 20% benefit to a tractor configuration. We have two canards in our club and we have tons of tractors in our club. A few of the tractors are very slippery. Of course, both canards are very slippery. Not only are the canards not slower, they pretty much dominate.
I'm not at home so I don't have access to any documentation or any real comparisons.
Hey Dave and Sleek... why don't you two design a front mounted prop gear case for the Bravo? You could even use a bunch of Bravo components to get people 20% gains in performance and efficiency. Look at the money people are kicking out for drives these days. Think how much people would pay to be able to do 120 mph with a boat that could only do 100 mph with a standard pusher Bravo.
Surely you could make a ton of money off that kind of efficiency gain.
As for me, I think I'll remain skeptical until the facts are in. I remember... it was quite a while ago... a new design was brought forth with much hype and was going to revolutionize an industry but turned out to not be quite as good as promised. I learned from that experience all those years ago and tend to be more conservative these days.
That's resonable. I'm not and engineer or designer either... I've dabled enough in this over the years to know there is probably no "right" answer.
But isn't it fun to argue... :D
There is also more than one way to measure efficiency in aircraft. All out speed is one, but speed per HP or maybe speed per pound is another... it just keeps going and going. Remember the CAFE standards???
The problem I see with a tractor configuration in a boat (which I guess is the reason why we are all here) is the powerplants are all mounted on or near the stern of the vessel. That would be like placing a tractor propeller right behind the passanger compartment in an aircraft. I can think of only a handfull of airplanes that even attempt that, and they all have pylon mounted engines.

[Tom Brown]

But isn't it fun to argue... :D
You noticed that too? :idea:
The problem I see with a tractor configuration in a boat (which I guess is the reason why we are all here) is the powerplants are all mounted on or near the stern of the vessel. That would be like placing a tractor propeller right behind the passanger compartment in an aircraft. I can think of only a handfull of airplanes that even attempt that, and they all have pylon mounted engines.
I just don't see a big efficiency gain of one system versus the other. If I had to guess, I would guess the tractor would be a tiny bit more efficient than the pusher but forget 20% or anythign like it. That's a wild guess by someone who is basically uneducated.
... now something that is proven is the efficiency of winglets. The vortex that rolls off the bottom outer edge of a wing and rolls down onto the top of the wing (reducing lift) can be largely eliminated by the use of winglets.
Has anyone tried winglets on a prop? Those fockers would blend the hell out of anything that fell into their grasp but it would be neat to see if prop slip could be reduced by eliminating the vortex that rolls off the outer trailing surface of a prop and around to the leading surface of the prop. That has to be an inefficiency.

[Sleek-Jet]

... now something that is proven is the efficiency of winglets. The vortex that rolls off the bottom outer edge of a wing and rolls down onto the top of the wing (reducing lift) can be largely eliminated by the use of winglets.
Has anyone tried winglets on a prop? Those fockers would blend the hell out of anything that fell into their grasp but it would be neat to see if prop slip could be reduced by eliminating the vortex that rolls off the outer trailing surface of a prop and around to the leading surface of the prop. That has to be an inefficiency.
Yep... Hartzell makes what is called a "Q" tip prop... It has a short tip-let (??? I think I made up a new word :D) at the end of the blade. The reason they make it is the same as putting winglets (tip sails) on airplane wings, but the application is different. Not alot of thrust comes from the tip of the propeller anyway.
From Hartzell's website:
What is a Q-Tip propeller? What are its advantages?
Q-tip propeller blades are formed by bending the tip section of the blade 90° toward the face side.
Aerodynamic improvements include a reduced diameter and decreased tip speeds. This results in quieter operation and reduced tip vortices. The 90° bend reduces the vortices that, on traditional blades, pick up debris that can contact the blades and cause nicks, gouges and scratches.

[BajaMike]

I thought they were called "skymasters" ?
RD
They were technically called a 337 "Skymaster" but everyone who flew in called it a "Skymasher"....they shook the hell out of you.
:rollside: :idea: