The_7

Anyone know anywhere (website,etc). that has info on the specific mathematics of the rotary engine, specifically the rotor/housing combo. I know the housing has an epitrochoid shape and i inderstand how an epitrochoid is created, but how do you figure out what radius to use for the circles so you can have a triangles apexes touching the side at all times?

nevarmore

http://www.rotaryrefs.net/

Go to Books & Info and download 'Rotary Engine' by Kenchi Yamamoto, it has everything you need.

fastcarfreak

The rotors arent exactly triangle.

mwatson184

If you connect the 3 apex seals by a line they are

I believe they are a "gothic" triangle, if you draw an arc from one apex seal to another using the third as it's center for all 3 faces, you have a gothic triangle.

-Marques

Kenku

Nope... having tried a mathematical model doing the gothic triangle idea, they overlap the rotor housings. I came across stuff that does work, but don't remember where.

nevarmore

The book at that link has the exact formulae for the housing and the rotor.

FD_dave

dang! i've been looking for this book for a long time. thanks so much! that site's awesome!

glemmers

Here's an Excel spreadsheet I started a year or so ago to evaluate port timing on a 13b. I had plans to calculate apex seal velocity/loads/rubbing angle as well, but haven't had a chance to get this calculations added yet.

The link to the Rotary Engine book is awesome! I haven't seen these equations before. No need to derive them now.

Glenn

glemmers

ALright, how do I upload an Excel file?

SPOautos

Can anyone calculate the chamber volume per degree thru the entire compression phase? It needs to be very accurate and I have NO idea how to do it. I'm a finance major...not engineer haha

cmartinp28

www.rotaryengineillustrated is the best site that easily explains the mathematics and physics about the engine

KevinK2

http://www.mikesdriveway.com/misc/rotor.doc

MikeC came up with this. there is an integral for "d', which is the same as piston displavement. Pic starting Theta (crank) and use d value x face area + min volume at tdc to get total vol at ea deg of compr.

glemmers

SPOautos, PM me an email address and I can send you an Excel file that does what you are looking for.

P.S. Sorry for the slow reply, been a hectic week.

Glenn

MikeC

It's just a sine wave:

V = Vmin + Vswept * (1 - cos(a / 1.5)) / 2

Vswept can be calculated accurately but you have to measure Vmin.

cmartinp28

www.rotaryengineillustrated.com

KevinK2

great site, but not much math there

try

http://not2fast.wryday.com/engine/rotary_design.pdf