wiggle drive propulsion application

Nobody needs to explain me, standard terminology.
If you are going to measure the forward force of the propeller. You don’t measure LIFT you are measuring THRUST. If you are talking about a helicopter you can measure LIFT.
I am still waiting to se the answer of how is the thrust produced by an oscillating tail.
I know how and why.

 

No one is disagreeing that ultimately what is of interest for a propeller or an oscillating fin propulsion device is the thrust.

There are two related but slightly different definitions of the word "lift". One is the vertical force supporting an aircraft, balloon, etc. The other is the component of force normal to the incident flow. The second definition of "lift" can be very useful in understanding and discussing how propellers and oscillating fin propulsion devices work.

If you know how and why then why don't you tell us. This forum is about exchanging information and increasing understanding. If you know but are not interested in telling us then why are you spending time on this forum?

 

In my post 217, I am showing how tail and wings are producing the thrust. The learned forum members, don’t except it. Everybody knows how birds fly and how fishes swim. They move their wings and tails, but how they are producing thrust is not accepted.

 

Thanks. A novel explanation of the fluid mechanics.

 

Changing direction of some parts doesn't imply net energy loss

Rotating parts like turbine blades are also changing direction (in two dimensions, not just one like the piston). But it doesn't take any energy to create the centripetal acceleration because the blade on the opposite side accelerates in the opposite direction, so the centripetal force on the blades is internal to the turbine, and not provided from outside.

The same can be true for a well designed piston/crankshaft arrangement: Two pistons always accelerate in the opposite directions, so the forces needed for their acceleration are internal to the whole arrangement, and not provided from outside.

 

Different cases. A turbine with all but one blade removed or an unbalanced flywheel will spin with constant kinetic energy except that due to bearing losses or "aerodynamics". The force required for the centriputal acceleration is normal to velocity so no work is done.

The piston/crankshaft arrangement will exchange kinetic energy between the piston and crankshaft, but the total energy of the piston(s) and crankshaft will remain the same. This is true irregardless of the number of pistons. The pistons are not just changing direction periodically, they are also changing speed periodically which in turn causes the rotational speed of the crankshaft to vary periodically .

 

Yes, that is a difference which makes it trivial to see for the turbine. For the piston/crankshaft arrangement it is more complex.

Yes, just like the KE of the turbine.

But even if the total KE of piston/crankshaft would vary periodically, would that necessarily mean loses? It just stores some energy temporally, and puts it back into propulsion or compression of the gasses.

 

I assumed the piston/crankshaft wasn't doing any compression.

If the piston is moving up and down in a sealed cylinder filled with a gas and the piston and cylinder walls are perfectly insulated so there is no heat flow then there would be an exchange of kinetic energy in the mechanical system and gas, and thermal energy in the gas. In that case no overall loss. Allow heat transfer between the gas and its surroundings and the analysis is more complicated.

 

I don't really want to insult anyone here, and i know there is a great deal of expertise here, its fantastic.... but the doubt & scepticism is overwhelming, thanks !
I really don't know what was worse, doubting that i'm the actual inventor and its an original Invention or wether it was the overwhelming disbelief in its function.
Thats Ok blokes i will go away now ! i will just continue playing with my little toy boat in my lil duck pond whilst you men go to sea... i'm happy with that !
Sorry old Kjell your on your own here, thanks Boston, i think you were the only bloke to offer any encouragement !
I will leave you with this pic, make of it what you will !

regards
Craig
Swashdrive

 

so many things went wrong in this thread.

Generally I have to side with Jeremy's last post. If using the CORRECT term lift gets ridiculed its hard to believe that we are going to see a very profound explanation of the phenomenon from that direction.

But swash drive you have given pretty good input and your device looks very cool - and I can see specialty applications where it could really work well - like the original post's idea of powered surfboard.

But you need to grow a thicker skin. People trying to get an answer to "why it would be more efficient" is only healthy questioning. As Jeremey said - a propeller can have very high efficiency too. In that light its hard to believe that a switch from (an ideal) prop to ideal fin drive would result in dramatic efficiency gain. It seems far more likely that the propeller that was used in comparison was not well optimized or didn't get clear water flow or some other issue.

None of this is to say that your drive doesn't have merits. Just that reading the whole thread again all I will know is that based on gut feel (not clearly measured) comparisons your drive is (supposedly) way more efficient - no idea why though.

Its not rudeness to raise the questions of why and how and how was the differences perceived. It is normal conduct of trying to understand.

cheers

 

My first negative rep ever. Someone felt like anonomously knocking me. This was their comment: "irregardless"??!

Here is where I used it:

(bolding added)

Fascinating that someone felt like use of a word which is not insulting or obscene was worth negative rep, and even more interesting that they decided to hide their identity.

 

Old story I'm afraid. If you can't attack the argument, go for something trivial and hope nobody notices the switch.

PDW

 

Thank for this comment. It is nothing new. The nature has been using it for thousand of years with very god result.

 

You can tell me all about it,show me formulas,etc but just show me one working and getting better mpg than the identical boat and hp with a prop and I'll believe it it.

The diesel electric guys couldn't.
So may I suggest getting into the shop and building one for a small runabout,and show us.

 

how did you dare?

"Irregardless is an informal term commonly used in place of regardless or irrespective, which has caused controversy since it first appeared in the early twentieth century. Most dictionaries list it as "nonstandard" or a word which has become socially acceptable. "Nonstandard" means the word is a colloquialism, not "incorrect" or not a word."

(from wikipedia)