On Sun, Jul 3, 2011 at 10:35 AM, Don <donmaguire1@hotmail.com> wrote:
> Hi Darald,
> The rotary engine #2 is built with ball bearings as rotor supports, with .010" clearance on all rotor sides. The gears and bearings are out of an RX-7 transmission. It should be able to rotate at at 8000 RPM.
> The piston equivalent of a conventional engine is the nub on the top rotor in the diagram,
> http://groups.yahoo.com/group/wastewatts/photos/album/1604589506/pic/35935352/view?picmode=&mode=tn&order=ordinal&start=1&count=20&dir=asc
> The center of the nub is 3.250" (.27') from the rotor center. This gives 20.36" of circular travel per rev. at the center of the nub. The nub (piston) displaces 1.73" sq. X 20.36" = 35.2" cubic of displacement/rev.
> The actual power stroke was determined by experimental means as when rotation was caused by air pressure being admitted to the engine. The power stroke was 16.3", the non power stroke was 4.06" this ratio is 4:1 in favor of the power stroke or %75 power, %25 non power per rev.
> Unlike a conventional (piston/crank shaft) engine that has max torque only when the crank angle is at 90 degrees and goes to 0 torque at TDC and BDC, my rotary engine piston is always at 90 degrees, the entire rev. and can maintain content torque.
> So with 100lbs of steam acting on a piston of 1.73" sq = 173 lbs of push at the piston (nub), thus with a .27' torque arm with 173 lbs of push = 46.9 ft/lbs of torque during the power stroke or an average torque per rev. of (46.9 x %75) 35.2 ft/lbs. torque.
> HP = torque X RPM / 5250
> So with 100psi of steam the theoretical HP, assuming %100 efficiency, at 5000 RPM is.
> HP = 35.2 X 5000/5250 = 33.5 HP.
> I built the engine very strong, I suspect it can handle 100 psi and 5K rev. easily.
> I have no source drawings or patterns, it is all out of my little head.
> After the build I did find some information in a book by F. Wankel (Rotary Piston Machines) that categorizes all rotary engines.
> Best regards, Don
Interesting!!!!!!!!
I was looking at a series kind of thing with a Wankel engine as a
first stage and then a piston stage (or two) to get more of the energy
out of the steam. I was thinking of using much hotter steam and
pressures in at least the 600 psi range and possibly to the 1500 psi
range. As I am both a certified pressure welder and a machinist I
haven't been too worried about using these kind of inputs as I have
worked with items capable of much higher than that!
So I understand that you have not actually had this engine running on steam?
If you have - - did you measure your efficiency at all? If so - - what was it?
Thanks for the ideas and information!!
Darald
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