Just how fast can a paddler go?

[bogstandard]

Just thought I would let you see a little project I am working on.

Turned it on and Bandit did a runner. Maybe he isn't as deaf as I am.

http://www.youtube.com/watch?v=YpcQ4JinhzI

Now, just how fast should paddle wheels turn.

John

[derekwarner_decoy]

Goodness PD's  & we may need some assistance from a newer Member....Key Board Kenny

John....I thought your latest turbine sang about >>>>> 44 notes or 1/44 staves up from from middle C? which is about 22,420 RPM....or was it TOO much  when I listened 

Anyway.... to read you posting's again on PD's bogstandard......don't worry too much ...I will post over a few old bones  ...that will get Bandit back  ...

Was Vinnie...'the more mature & artistic one' listing to Beethoven via the earphones & not suffered the turbine DRONE NOISE,,,,,best regards

Oh BTW...do you have a 6.0 mm diameter x 0.5 pitch die nut?...as my new glass tubed lubricator is reported to have the same internal base endcap thread.....

[derekwarner_decoy]

Hi PD's......I have just consulted the SKF bearing calculation WEB site John ...... ...& it suggests that if you exceed B1M [which I think was one million revolutions per half life of the pre installed greese in the ZZ shields...which is naturally divided by the actual RPM]...the whole thing may sieze up

Not sure  .....if SKF had installed real grease instead of GOOSE fat the problem may not have existed  ........

[mjt60a]

That looks interesting, I'd like to see a model TS Queen Mary powered by one of those!

[Tug--Kenny]

Hi everyone.

 The frequency given off sounded like eleven thousand cycles per second to me, although I doubt the shaft was turning at this speed.

What would you do with that speed of revolution. Gears and grease would be a problem, not to mention torque at the end of the gear train.

Nice engineering though. Well done.

Ken

[Eddy Matthews]

Forget paddlers..... But imagine a steam powered hydroplane using that little engine!! Fantastic John!

[bogstandard]

Derek,

I turned the compressor off before doing this vid, just in case the noise of the compressor drowned out the noise of the turbine, little chance. So really it didn't have much chance of building up too high a speed.

Before I shot the vid, I wacked the air up to about 60psi, and the engine started to run away and I had to shut it down. The bearings are only designed for a max of about 45k, and yes, they do need regreasing. I am going to make a little tool to recharge with grease without taking the shields off.

The noise you were hearing when it starts up is the air hitting the pockets, 18 on each rotor (one every 20 degrees), the second rotor is offset from its twin by 10 degrees, so in theory (please don't go down that route, my brain hurts enough as it is)the frequency should get higher when the second rotor is brought into play.

I am hoping to run it at about 30k and reduce down with a 50-1 gearbox to get it in the range of large model boat props, as requested by the customer. This is a proto, he wants a matched pair to fit in a 10ft destroyer. The size of this one will be reduced by about 1/3. It is his problem how he gets enough steam to drive them.

With regards to the thread, it sounds like an oddball. As you know standard coarse 6mm has a 1mm pitch and the fine 0.75mm. You could get one ground up specially, but would be rather expensive. I could go thru all my turning charts to see if my lathe can be set up to do it, but doubtful. Again it would mean the expense of special changewheels.  Loctite by the way works wonders, wack it in and stick it.

BTW, Vinnie is unmoveable, try it and you are dead meat. He only moves when HE wants to.

John

[derekwarner_decoy]

OK PD's.....bogstandard asks that.... "so in theory (please don't go down that route)"

couldn't resist.........so if one nozzle on one bucket wheel produced the audible ~~~~~20K...heaven's pray what 2 nozzels on 2 bucket wheels will produce  ...you are certainly correct of an approx ~~~~~~~1M x 40K RPM bearing life....this sounds a big number....but NO

The DRONE I spoke of is a resultant OOB [out of balance] condition on the run down <<<<<<......on speed increase>>>> the OOB is nullified by the forces [rotational stresses], where as on the run down <<<<<< it is the decaying rotational stresses that create the DRONE...does that make sence?

If you intend to loop up 2 nozzels & 2 wheels..... the restraining welds to the engine mount+bench.......
...or should we hope your customer has a sturdy structure ...& enough to balance two engines & the gyroscopic [counter rotating] OOB in his 10' destroyer

[steamboatmodel]

Hi John,
From the photo, it looks like you will be running two nozzles in parallel for forward and one for reverse, have you considered using a multistage turbine?
Regards,
Gerald

[clifforddward]

It would be interesting to see the boat owner's ideas on steam plant....maybe a flash steam unit of some sort?  Even then, think of the size required!

Beautiful piece of engineering....makes one wonder about other applications for this type of rotary steam engine...

Regards,
Cliff

Cliff Ward
Cary, North Carolina
USA

[bogstandard]

Gerald,
I had already thought of that, but to make a very simple engine it would not be feasible. that is why I went for an impulse rather than a reaction turbine. Scavenging the spent steam from the first stage would be the problem with this design. The steam enters by a nozzle, hits the pocket, pushes it forwards until the next pocket is in line with the nozzle, then it is on the way out of the chamber. The main problem was to stop the steam staying in the chamber and pressurising it, in that situation the rotor would just slow down as you would be losing efficiency from the nozzle. By scavenging and getting rid of it straight away prevents the build up of pressure. I know it is a different design concept, but imagine putting a metal plate with a small hole in it over the exhaust of a gas turbine engine, the engine would soon let you know it was unhappy.

Cliff,

Have a look at this one

http://modelsteam.myfreeforum.org/ftopic9874-0.php

I think that is just a single rotor version.

I have already told the customer that a rather large generating plant would be required, even maybe a flash steam boiler. The problem with that side will be his, not mine.

These are really just a gimmick engine, they have been tried to be mass produced for model boats before, but they never really took off (maybe the wings weren't big enough)(joke). But I will try to produce whatever is required if it grabs my interest enough, and doesn't cost a lot of money.

I think this has been posted on here before, but this is one I did for myself showing how a turbine can generate electricity.

http://www.youtube.com/watch?v=KW6V7JWbQwk

John

[derekwarner_decoy]

OK PD's...I acknowledge that bogstandard suggested we not go down a terrible technical path so  ...lets just consider a few basic explanations & this will be enough to wake the {non living}

I also notice John has reverted to imperial dimensions .....0.014" as shown below

So....if we have 18 impulse buckets per ring @ 30K RPM........

..... 18 x 30,000 = 540,000 pulses per minute...[this is just over 1/2 a million be they imperial or metric pulses.. ]

If each turbine rotor bucket were 0.001" out of position...would mean that the turbine bucket ring was sum of 0.540" [1/2"] out of wack per minute & hence the vibration >>>>>>DROAN with the collapsing [energy] [steam] field on slow down

If this is not bad enough  ...adding or looping the second turbine rotor bucket ring will = 0.540" x power of 12.2 which suggests that the device will self destruct beyond 20K RPM @ 2.15 PM next Sunday [after Church & a few  for me or a few  for Gerald]

Seriously though..we can see the critical dimensional relationship when we introduce the third element ..... movement or in this case ....... rotation

Next thing will be when Eddy responds & confirms he was responsible for the quality grinding of Rolls Royce gas turbine engine  rotating bits   

[Bierjunge]

Asking how fast a paddleboat can go, how about this fast? http://www.youtube.com/watch?v=02DKzQFsgJU

Moritz

[bogstandard]

Sorry I haven't been as active as I should, lots of things happening at the same time.

But I have managed to get this little brute semi tamed, I can now cut off its life blood at will.

My compressor is just about to give up, so only about half the pressure and volume as it really requires, but did do this little vid.

http://www.youtube.com/watch?v=1_Ey8v7fgig

John

[Eddy Matthews]

Really impressive John 

I'm surprised by just how controllable it seems to be, and how quickly it will go from full ahead to full astern.