Lightweight Horsepower

[mate88]

Does anyone know of a PRACTICAL, USEFUL I.C. engine that produced 1 hp per lb or close to it? Something in the 30 - 35 hp range. And it should last more than 10 min! I remember seeing some neat Italian 2-cycles somewhere.

 

[Entropy455]

A Honda CR500 dirt bike engine makes about 55 horsepower, and weighs about 52 pounds. That's including the transmission.

2-strokes make impressive power.

If you are looking for serious power in a light-weight package, look into 2-stroke marine outboard engines. . . .

 

[lohring]

Lots of chain saw engines would fit in the smaller sizes. If you want to get serious look at hot saws. Modified Zenoah 26 cc model marine engines develop over 6 hp at 15,000 rpm with a tuned pipe. The Aprilia 125 cc motorcycle engine developed 54 hp. Plenty of motorcycle two strokes would fit even at a lower state of tune. If you are looking at something bigger consider that supercharged snowmobile engines have been built with over 800 hp. A current jet pack uses a high power two stroke driving ducted fans.

Lohring Miller

 

[mu38&Bg#]

What is the application for this engine?

 

[Niels Abildgaard]

If you are looking at something bigger consider that supercharged snowmobile engines have been built with over 800 hp. A current jet pack uses a high power two stroke driving ducted fans.

Lohring Miller

Hello Lohring

Can we have a link or two describing such totally uncorrect things?
Sounds interresting

 

[lohring]

I can't link to the site, but pictures are below. The cylinder castings were from CP Industries. Take a look if you're interested in the porting a really high power two stroke needs. A video of some testing and runs when the engine was only developing around 530 hp is here.
[ame]http://www.youtube.com/watch?v=qpoEjY7KDdo&feature=c4-overview-vl&list=PL71E5003AA3204632[/ame]

Lohring Miller

 

[lohring]

The most powerful small engine we've developed is the CMB 35 at almost 12 hp. The details are in an article on Model Gas Boats.

Lohring Miller

 

[mate88]

What is the application for this engine?

U/L aircraft - most available are quite heavy (= reliability) I did find some detail on the Rad-Cam engine - I've been working on a very similar design hence my need for eliptical gear. I can't seem to find any further info on it's current state.

 

[mu38&Bg#]

That's what I expected. It seems many ultralights fly with existing ultralight engines.

Rad-Cam has not updated for many years. Like all "innovative" engines it suffers from many issues, typically sealing.

Greg

 

[mate88]

Your handle DieselPilot would seem to indicate you fly behind a diesel power plant - true? What's the airframe? I know of a couple of guys 'round here with Ford 3.8 V6 power in a PA18.
Rad-Cam had poor sealing? Any further details anyone?
My version (completely independently 'invented') is a 6 cyl 2-cycle w/each cyl 'sealed' as by normal 2-cycle practice and I think it is less complex than the Rad-Cam.
Just called Earth-Star in Ca, last known home of Rad-Cam since 2003 - awaiting reply.

M8

 

[dman]

for power density 2-stokes rule but they are fuel hogs and the mechanical simplicity doesn't always lead to reliability. many motorcycle engines would fit the requirement 2 and 4 stroke. but they have built in transmissions and often water cooling. so you are on to snowmobile engines. or perhaps a hybrid of an aviation engine with some aircooled motorcycle parts.

 

[Niels Abildgaard]

Hello mate88

What is the propeller diameter and rpm You have in mind?

 

[mate88]

60" and 3000 rpm - I think I may be seeking the impossible dream ......................... but stranger things can/have happened.

 

[mate88]

..........................need to add that other options (motorcycle, snow blower etc) have all been tried with mixed results. My design MAY be diesel too - again weight plays a negative role for flight, but may not be much of a headache elsewhere.

 

[lohring]

Aircraft engines have very different standards. The most critical is that it runs until you shut it off no matter what. I wouldn't get fancy with anything that doesn't have a lot of hours running in aircraft. However, a V4 two stroke powers this jetpack. I have no other information or pictures, but the strengths of the simple two stroke are power to weight, especially in full throttle applications. That includes boats. Today most ocean going cargo ships use two stroke diesels. Their fuel economy is better than anything else in this application. Smaller marine two stroke outboards now also have advantages over four strokes. Modern electronics with direct injection can solve the old issues of emissions as well as fuel and oil consumption.

Lohring Miller

 

[Niels Abildgaard]

Hello mate88

Try to look at a 90 degree inverted V2proposal

http://www.homemodelenginemachinist.com/f26/2-stroke-2-cylinder-engine-1155/index3.html