Science Buddies: "Ask an Expert"

Dear Moderator,

My name is Ethan Kester, I am a ninth grader interested in competing in the INTEL/ISEF science fair. I want to design a new modified form based on the quasi-turbine engine, to determine if my modifications increase power/efficiency. I would like to double the number of occasions for combustion in the combustion chamber, and see if it continues to increase power or if a law of diminishing returns kicks in at some point. I will need to get together with a machinist or automotive engineer so that I can actually manufacture my engine, and then test it. First of all, I need to know if my idea is even possible, or am I wasting time? I live next to the Volvo plant in Dublin Virginia, and think that someone there would be very good to work with. How do you think I should proceed?

Hello Ethan,
As the term "quasi turbine" was new to me, I did a quick websearch and see that it's a 4-lobed rotary internal combustion
engine. There's quite a bit of mechanical complexity in the design which will make fabricating an engine quite difficult,
and I don't think the Volvo engineers may be able to assist that much as this type of powerplant probably isn't in their
present line of work. Quite a bit of specialized tooling would be required to get a working prototype for your
purposes, as establishing a functioning baseline is essential to being able to measure effects of modifications such as
what you propose.
I suggest that you consider modifying your plan of attack to use a commercial 3-lobe Wankel rotary engine, and use that
as a base upon which to establish your experimental tests. One such engine is manufactured
for model aircraft use and was available at one time from Tower Hobbies, www.towerhobbies.com; the Japanese manufacturer
is the OS Max company and this item is labelled as "OS Max .30 RC Wankel". This is a fairly small and compact device and runs
on model airplane glow fuel.
A good technical description of the OS Wankel engine can be found here:
http://ludens.cl/aeromod/wankel/wankel.html You can probably find more details on a websearch.
The advantage of using this particular engine is that it'd be fully functional and operational, thus allowing baseline measurements; and
would be easier to modify than a larger, more complex device. It's not cheap, however, and you may be able to purchase one at a
reduced cost from other sources - EBay, model airplane enthusiasts, etc.
Before you purchase this item, however, you should work out a research plan; establishing an experimental hypothesis, as well
as dependent and independent variables, test measurement methodology, and other research plan details described in he Science Buddies
research hints and tips pages. Good luck!

Peter Young

Given the complexities pointed out by Peter Young, I suggest you begin your study by understanding thermodynamic cycles. It is the principles of thermodynamics that govern how internal combustion engines work. With knowledge of thermodynamic principles, you can determine the theoretical maximum amount of work an engine can produce. With that knowledge you can begin to understand how much you might be able to improve a given design.

You can get started on your studies here: http://en.wikipedia.org/wiki/Thermodynamic_cycle

Good luck and have fun!