Home built two stroke engine!
 

Hi guys...

For months now i am thinking of designing an ultralight aircraft and also design and make a home built two stroke for it.

I'm looking for ideas about designing a 2 stroke ~40-50hp gasoline engine.

Any thoughts ?

RE: Home built two stroke engine!
 

It's called Rotax.....

RE: Home built two stroke engine!
 

Nice answer..

RE: Home built two stroke engine!
 

T.O.M. you forgot to put 503 on the end of that reply. ;) I guess the 447 would fit at the lower range too.

I have to agree with him on a more serious note. It would be allot of work to design something that is already available and pretty much bulletproof. It is always interesting to see new projects though.

RE: Home built two stroke engine!
 

The problem is in the cost of development. Certainly there is always room for the development of new engine designs. Take a look at the twin piston/cylinder two stroke designs the Germans are currently working on. However, the cost is prohibitive. You could adapt a snow mobile engine such as was done early with a UAV platform but there would be a lot of additional time, labor, and expense in doing so. Rotax already has several powerplants availble that meet or exceed the needs of just about any ultralight that fits the legal description. Going from ultralight to light sport aircraft and you already have another group of engines that fill the need.

Any of those engines would come up untold thousands of dollars less expensive to use, and have already been thoroughly flight tested to assure long term reliability. So unless you're brutally wealthy, or have an engineering staff and production facility that needs something to do, developing a new two stroke is just not a cost effective project.

Now if you could come up with something light that would run as a two stroke on diesel fuels and not generate a cloud of pollution as two strokes are prone to do you might have something. Design a "green" two stroke that develops greatest torque at under 2500 RPM without gearing and does not suffer a power loss in doing so? That would be a lofty goal.

RE: Home built two stroke engine!
 

That I think has always been the obstacle. Trying to develop a small light engine that can produce good torque in those low rpm ranges where propellers operate efficiently. Not an easy task.

RE: Home built two stroke engine!
 

Outrunner brushless electric motors develop good torque at low rpms and allow gearless drive of large props. Did the rotary engines of yore develop better torque at lower rpms than the equivalent radial engines? Thanks.

Richard

RE: Home built two stroke engine!
 

Can you imagine the size of a 40 to 50 HP outrunner? Worse, the size of the batteries nneded to power it. You'd need a cord connected to a generation facility.

The WW1 rotarys were not all that great, but that's what they had to work with.

RE: Home built two stroke engine!
 

Can you also imanage the fire ball that would happen if you shorted out the battery for a split second ! http://www.rcuniverse.com/forum/js/f...humbs_down.gif

RE: Home built two stroke engine!
 

http://www.rcuniverse.com/forum/js/f.../lightbulb.gif

RE: Home built two stroke engine!
 

There goes the Hoover Dam generating station...

RE: Home built two stroke engine!
 

You fellers living under a rock? LOL Ultralights are flying with E power http://www.electraflyer.com/ http://www.fly-flightstar.com/

RE: Home built two stroke engine!
 

The question was did the rotary engines back then develop more torque than the radials? The comparison was to the larger diameter rotating mass in the case of the outrunner vs the inrunner, and of the rotary vs the radial. Or does anyone not know? Thanks.

RE: Home built two stroke engine!
 

WOW! A 56000 mAh lipo pack & 165lb of thrust. Now how can I fit that into a 33% Extra?? :D

RE: Home built two stroke engine!
 

The WWI rotaries had a tremendous amount of torque, considering their HP and rpm range. Unfortunately is was unusable 1/2 the time and almost to much the other 1/2. Many of the planes would turn on a dime one way and would barely turn the other.

RE: Home built two stroke engine!
 

some of this turning better way and not the other was due to gyroscopic precession of the spinning engine mass with the rotary engines

RE: Home built two stroke engine!
 

Ya, but when that cylinder mass suddenly went from low throttle to high they learned what torque really meant!

RE: Home built two stroke engine!
 

Well your right....but how long will the battery last before it needs replacement? Also what is the total price for airplane...battery & charger...with what kind of warrenty? Thanks Capt,n

RE: Home built two stroke engine!
 

The battery is 8500 bucks. I watched one of the videos and they say it will last 800 cycles or about 10 years. I have difficulty in seeing a battery last 10 years, but hey I am no expert.

RE: Home built two stroke engine!
 

My truck battery had to be replaced 3 times since new in 2005. Had to pay a pro rating thing 2 times. I hate to think of what the new electric car batteries will cost $$ $$ $$$ $$$ $$ $??????? Capt,nhttp://www.rcuniverse.com/forum/js/f...humbs_down.gif</p>

RE: Home built two stroke engine!
 

Think about what goes into their production/disposal and you wonder were people came up with the concept of electric power being "green". The only thing green about it is the money spent in chasing it.

RE: Home built two stroke engine!
 

Thats close to $100 per hour to fly that thing! I'll stick with fuel, air and spark thank you.

RE: Home built two stroke engine!
 

Me too. Plus there's something important missing with an electric motor. Sound!!

It's so dissapointing to see a B-17 model go flying by with 4 electric motors. It just isn't right.

RE: Home built two stroke engine!
 

Goggle MYT engine from Angel Labs. Might be the engine to solve all our problems.

RE: Home built two stroke engine!
 

Exactly!