I've bin researching engines for my Rigid-wing hang glider
for a few months now ; for weight to power , i can't find a
better engine than the 3W-275xi-B2-TS. Being a twin
cylinder ; i can expect much less vibration than the single
cylinder engines, that are currently available for ultralights.

Could someone here, tell me about dependability of this
engine ?

About how many hours between rebuilds, can i expect ?

I would need a prop-pitch speed of about 40-mph ; does
anyone here know about how much thrust this engine
will produce ; anything over 125Lb will do in direct drive.

Below is the glider i plan to use this engine on ; notice
the pilot , (me) is using 2 fake legs to run the take-off !

The glider uses flaps, for L/D control, and spoilers for
turning. It's a fully cantilever all carbon frame ,with
D-tube ; and built like a Tank, (it ain't gonna break in the air )
if i keep it under 60-mph.

Thanks : Bille

Rebuilds you can expect 500 hours for TBO from what i have been told by Gerhard @ AI

The twin spark is a great option for you use, Greater Reliability.

Speak to either 3W Direct or Gerhard @ Aircraft international they will have other info for you.

On a side not i believe DLE also make some motors for para glider use too. With Gear reduction etc.

500 hr is quite good ; more than I expected !!!

With a decent climb-rate , I figure the engine should only run
less than 10-15 min each flight, (need 500 to 1000 feet altitude
to catch a thermal ) ; then shut her down and and fly for hours on
the power of the sun !!

Yep -- i thought the same ; on the twin spark .

DLE makes a decent engine ; i have a DLE-20 in my Waco biplane .
That DLE twin para-motor, your talking about, puts out 20-Hp 23hp
with the premium muffler ; i need a minimum of 22 to 25 hp, if i want
to ground launch at King mountain Idaho, at 5500-ft. That DLE, might just be enough ; it's not a twin spark though, so i'm still leaning towards the German made one, and do mods like a reduction if needed.

Thanks for the info : Bille

The problem I see is props. The 3W is designed for about 7000rpm. At that rpm you need a 6” pitch prop for 40mph prop speed. My best guess is you would need something like a 40x6 or 42x6 prop. At least for RC use, I’m not aware of anyone making a prop that flat at those diameters. I think you really need a gear reduction system. With a 2.5/1 drive you could turn a 40x14 which would work better and be more efficient.

As for thrust I think with the right prop you should be in your 125 pound range.

For custom prop's -
http://www.princeaircraft.com
Loni will make you anything you need , Ive had & flown props made by Loni , excellent quality

Originally Posted by dshriver

... With a 2.5/1 drive you could turn a 40x14 which would work better and be more efficient.

As for thrust I think with the right prop you should be in your 125 pound range.

The FAA says i can use an adjustable pitch prop, if i want ; there
are at-least 3 company's, that build them, for this Hp range, and
they make both ground and in-air adjustable ones. With the
max pitch setting ; i'm not allowed to legally. exceed 62, mph
in level flight. My max VNE in turbulent air is 59-mph, so
that would work out just fine.


A belt reduction would be easy, and light ; could buy the
parts, and make it myself, (i have a 36" lathe) if things
need fitting.

Bille

Originally Posted by rooman

For custom prop's -
...princeaircraft....

They make a propeller that has a fixed pitch and relies on the forward pull of the propeller to automatically provide pitch change proportional to the amount of force being applied to the propeller disk!!
That would be WAY less complicated, than a hub that changes
the pitch . Does anyone make props like that for RC ?

Bille

The PAC "P Tip"prop is a torsion twist pitch prop , as rpm increases pitch decreases , it is an RC prop

The better question is where are you going to put this 3w and prop? You are tucked up close with not a lot of space for a spinning prop in front or to the rear of your person. They make craft designed for this type of flight, several fly over my property all the time. I would probably try one if it were not for the fabric chute being the wing.

Originally Posted by acerc

...
I would probably try one if it were not for the fabric chute being the wing.

Are you talking about a Powered Paraglider ?

I'm talking about installing an engine on a carbon ridged-wing
Hang glider, with aerodynamic control surfaces, that was
built stronger than a single pilot, (it's a two-place glider).
No Exxtacy, has ever broken in the air ; got to run it
into a Barn, to do that.

There are Many designs , for motorizing this glider, to choose from ;
Powered harness , to three wheeled trikes , and more ...

I believe the 3W 275, would be an Excellent choice , to
motorize, this glider ; and i think i'm asking the correct
people , if this engine is dependable ?

Bille

That second pic look's like fun. My 3W"s have been and what I still have is absolutely dependable. I can see that 275 pushing one along quite well.