The Wind Powered Sail-less Boat

And yet you can't produce a single, solitary lie that we have told.

I'll repeat the request ... find the lie. Produce the lie. Back up your accusations with quotes and post #s for Jeff to see. Otherwise it is you with the credibility problem.

JB

 

any engineer having worked on something for years would have a computational analysis completed many times
complete computer simulations probably as well
its what I asked for originally as any good engineer would and with in clearly not forthcoming
it begs the question why

why would engineers not do engineering on the the puzzle they claim to be writing a paper on

and yes I will point out that puzzle is someone else's work

you guys are clearly acting as a team
clearly manning the computers constantly
clearly moving from site to site
and clearly only in it to cause as much trouble as possible
it is hardly a stretch to suggest you are lying about your credentials when you dont even speak in the terms of an engineer

I would respectfully ask if Jeff is reading this that he reconsider your membership to this site

obviously you guys are lacking in the integrity we try and uphold

that make any sense to you cause its glaringly apparent to a lot of other people

have a nice day
B

I also note that you guys have some kind of policy of never allowing the last word
nother pretty cheesy way to go about things eh

you clearly offered to answer any questions we may have in whatever level of detail necessary
you refused to answer mine eventually admitting you had done no nonlinear analysis of the device
yet
you guys are writing a scientific paper on it
I highly doubt it
screams of dishonesty

 

And yet you can't produce a single, solitary lie that we have told.

I'll repeat the request ... find the lie. Produce the lie. Back up your accusations with quotes and post #s for Jeff to see. Otherwise it is you with the credibility problem.

JB

 

Just as a note, I'm happy to discuss DDWFTTW and in fact that is my preference, but as long as Boston continues to call our honesty into question I will continue to simply to ask him to show where we've lied.

As previously posted here more than once, we give credit where credit is due. Having spoken personally with the engineers to did it in the '60s, we know it's history to a level someone just reading on the internet can never know.

Find the lie, find the statement where we take credit for something that we did not do. You can't because we don't.

JB

 

Jeff
I will await your response before continuing on this thread
I would ask that you note the following

these guys are acting as a teem ( thug spamming ) going from site to site with a predetermined agenda

there tactics are obvious and include at first antagonism of dissenters escalating to personal attacks

the term Thug Spam is applicable to what they are doing

there tactics begin with an offer to answer questions of the necessary complexity to prove there point
they then refuse to answer the one question that would quell all dissent
for five pages

descending into a litany of antagonism rather than admit they have no engineering on the device, although at least one of them claims to be an engineer who is writing a scientific paper on the device

they seem to have a policy of starting a fight and then complaining about it

I believe they are clearly dishonest in both there approach and there claims

and if you notice in about five seconds there will be a response from one of them as they appear to be involved in an organized campaign that they have brought to this forum

I apologize for any inconvenience this may have caused
and ask for the ability to defend myself against what is a concerted organized personal attack

I respectfully request that you reconsider there membership to this forum

sincerely
B

 

Boston, you are demonstrating a fundamental lack of knowledge regarding the process for peer review publishing. One need not have invented a device to present for publishing a study regarding said device.

To the best of our knowledge we have personally conversed with every group that has successfully built and tested these DDWFTTW devices in history (we found only two before we built ours and two since) and we welcome input from anyone who knows of someone we haven't talked to. We are confident that we have built more variations and done far more testing than anyone on the planet. We can (and as shown on this thread, do) present the theoretical side as well as the demonstrational side. Our knowledge makes us as qualified as anyone and more qualified than most to present a paper for publication on this widely misunderstood topic.

I don't think organizations like the AIAA gives a rip what you think when it comes to accepting papers for publishing -- they're quite capable of making their own decisions and have a nicely rigorous process to do just that.

JB

 

And yet you can't produce a single, solitary lie that we have told.

I'll repeat the request ... find the lie. Produce the lie. Back up your accusations with quotes and post #s for Jeff to see. Otherwise it is you with the credibility problem.

JB

 

For those interested in building their own DDWFTTW device following is a link to the build videos for a device (based on a Mark C design).

http://www.youtube.com/watch?v=T-ArigMKhi4&feature=PlayList&p=B9620506705D182C&index=0&playnext=1

If someone would like a parts list I'd also be happy to post that as well though the video covers it.

-----------------------

Following are two links to video of another independent party testing their own version of the Goodman cart. Pelesi is studying for his Phd in Socal.

Part 1:
http://www.youtube.com/watch?v=9S2HHwfcz9Y

Part 2:
http://www.youtube.com/watch?v=A9owA...e=channel_page

And Pelesi's writeup:
http://projects.m-qp-m.us/donkeypuss/

JB

 

Mmmmmm, it could seem you're just avoiding a road which perhaps can come to a not desired end to you, or that you don't know how to do it , but OK, someone else is interested to try?

 

I'm sure it could seem that way. Perhaps someone else has a greater insight into the analysis you propose and can see that it would lead to something very meaningful. So let me ask you this... let's say I wrote that simulation. I'd make a bunch of assumptions regarding prop efficiency, advance ratio, internal losses in the transmission, mass of the frame, moment of inertia of the prop and wheels, size and pitch of the prop, etc. I'd use actuator disk theory to model the prop at the various conditions to cover the transient case of going from stand-still to greater than wind speed, and I'd come out with two plots. One would be a curve showing the energy flux at the input, and the others would show the energy flux at the exit - both as a function of time. I suppose it would be trival to then difference those two curves to compute the net energy flux in the control volume - so I could give you a third curve.

I propose that you tell me what we could glean from those three curves before I spend hours developing and debugging this simulation (and then hundreds of hours defending the assumptions made).

It's frequently a whole bunch easier to ask a question (even a poorly posed one) than it is to answer that question.

So I'll ask you to do your homework before putting me to work on what seems like a wild goose chase. How will you use those three curves?

Do you know how to do this analysis? Is there even one shred of evidence that suggests the results would not look good for me (or that you could even make such a determination from this output?).

 

Guillermo,

Well i am working on getting a full analysis. I do not care if it is a lot of work or not , as i find the whole thing very intriguing.

What i am especially interested in is how would a high performance turbine boat transition from G < 1 to G > 1 . (G is gear ratio) That, and what is the highest V/W achievable given the efiiciencies and resistances. All this not just in the special case of alpha = 180 or 0 but at any heading to the wind.

When i feel i have made significant progress i will post it or post a link to my mathematical breakdown.

As i like to be thorough it might be a while but i promise to let you know when it is done at least to as far as i can take it.

 

I've done what I consider to be a full analysis on the downwind cart. That does not include the energy flux curves at the inlet and exit of Guillermo's control volume for the transient case he describes - primarily because I don't see the value those results provide. Do you intend to analyze that specific situation?

That I think I could give you in fairly rapid order. Would you care to characterize the efficiencies and resistances for me?

I assume we're talking about a boat with a big propeller above deck that operates in the air and a smaller one that operates in the water. If we're assuming both remain aligned with the longitudinal axis of the boat, then I think you'll agree in the downwind case the air prop acts as a prop and the water prop becomes a turbine. In the upwind case their roles are reversed (as it's now a boat that goes up-current faster than the current). In any case, if we're assuming they both remain aligned with the boat's axis, my interest is limited to the 0 and 180 cases (in fact I have little interest in the upwind case). I think you'll find that with this configuration the analysis of prop and turbine efficiency will get more than a little tricky with a cross-wind component. But I'll be very happy to read your analysis.

 

<<<<<I assume we're talking about a boat with a big propeller above deck that operates in the air and a smaller one that operates in the water. If we're assuming both remain aligned with the longitudinal axis of the boat,>>>>>>

First part yes.

Second part , no. To impose air prop remains aligned to boat' s centerline would be an unnescessarily great blow to the machine's performance. The air screw must be allowed to operate at any angle that provides the best performance.

<<<<< Would you care to characterize the efficiencies and resistances for me?>>>>

Yes, say energy efficiency = e (Work done by bottom prop vs work done by top prop)

Total resistance to motion D = D(V^2)

there is no cross wind component on either prop as they are both aligned with their respective flows. As for heeling and pitching moments , we can assume that they are sufficiently similar to a regular sailboat so as not to warrant an analysis of this already well researched subject.

 

The first one is rather tricky, since it depends MUCH on the operating conditions. The efficiency of a single prop/turbine can be very good (80-90%) in some situations, but very bad (30% or even less) in others. Especially in the DDWFTTW situation the efficiency of the air propeller is easily very bad due to very low apparent wind. With zero apparent wind the efficiency is zero by definition.

The size and gearing of the prop/turbines needs to be very different in different conditions. In DDWFTTW the air propeller must be huge, but a huge one will be way too big for side wind or upwind.

The total resistance is not well at all modeled with D=c * V^2.

The air prop/turbine can be turning, but it will produce side force, which needs to be balanced with a keel or a turning water prop/turbine. Otherwise the boat will have a huge leeway in many situations. Side force increases drag and this drag component can be very significant.

Joakim

 

I don't think I'm understanding your point here. Are you suggesting the prop on a Cessna would necessarily operate at zero-efficiency while the plane sat still with brakes set in the run-up area?