What's wrong with this engine?

[Fred the Red Shirt]

I was perusing some lists of Ultralight engines and noted that
the Limbach 275 was listed as 20 - 25 hp and 17 lb. I figured
that was a typo, since it was less than half of the weight of
other engines of comporable power--more likely it was 17 hp at
20 - 25 lb, still good stats. But I've seen it listed in three
more places as only 17 lbs or thereabouts including here:

http://www.ultralightnews.com/limbach/limbachl275e.htm

Holy crap! How does Limbach do that?

Now, since it develops max power at 7300 rpm you'd need
a 2:1 speed reduction or so to use a 48" prop, effectively,
right? Supposing the speed reducer DOUBLES the weight, it's
still pretty darned impressive. According to what I can find
on the history of Limbach, the design is based on a VW, but
is built from the ground up to be an airplane engine.

So, what is the down side to these engines? Do they cost a
gazillion dollars or blow up at 20 hours or something? There
has to be a downside somewhere.

--

FF

[AL]

While I cannot speak with absolute authority, a volkswagenesque engine
that needs to run at 7300 rpm would not seem like a high hour engine...

AL

> Holy crap! How does Limbach do that?
>
> Now, since it develops max power at 7300 rpm you'd need
> a 2:1 speed reduction or so to use a 48" prop, effectively,
> right? Supposing the speed reducer DOUBLES the weight, it's
> still pretty darned impressive. According to what I can find
> on the history of Limbach, the design is based on a VW, but
> is built from the ground up to be an airplane engine.
>
> So, what is the down side to these engines? Do they cost a
> gazillion dollars or blow up at 20 hours or something? There
> has to be a downside somewhere.
>

[Rich]

AL > wrote in message >...

> While I cannot speak with absolute authority, a volkswagenesque engine
> that needs to run at 7300 rpm would not seem like a high hour engine...

Other then having horizontally opposed cylinders, I see little
resemblance to a VW. This is a 2 stroke, and the airbox/exaust
doesn't appear to be in the weight. It's gotta be very very loud, and
I'm guessing a muffler would cut into the power.

Rich

[AL]

Hmmm. I'm not familiar with the engine. The OP mentioned it was based on
the VW. My bad assumption.
AL

Rich wrote:
> AL > wrote in message >...
>
>
>>While I cannot speak with absolute authority, a volkswagenesque engine
>>that needs to run at 7300 rpm would not seem like a high hour engine...
>
>
> Other then having horizontally opposed cylinders, I see little
> resemblance to a VW. This is a 2 stroke, and the airbox/exaust
> doesn't appear to be in the weight. It's gotta be very very loud, and
> I'm guessing a muffler would cut into the power.
>
> Rich

[Fred the Red Shirt]

AL > wrote in message >...
> Hmmm. I'm not familiar with the engine. The OP mentioned it was based on
> the VW. My bad assumption.
> AL

The manufacturer's website says their designs are based on the
VW so I daresay that volkswagenesque was apropos.

Thanks.

--

FF

[Ryan Young]

(Fred the Red Shirt) wrote in message news:

> Holy crap! How does Limbach do that?

It's a TWO STROKE engine. Compare it to Solo or Rotax engines and it
looks less remarkable.

> According to what I can find
> on the history of Limbach, the design is based on a VW, but
> is built from the ground up to be an airplane engine.

THIS Limbach engine has NOTHING in common with a VW engine. Limbach's
larger engines do, but they are 4 stroke engines of much larger
displacement.

> So, what is the down side to these engines? Do they cost a
> gazillion dollars or blow up at 20 hours or something? There
> has to be a downside somewhere.

How about absolutely no US distribution? Limbach engines WERE
expensive when they DID have US distribution (in the 1980's), and the
US$ to German Mark exchange rate is less favorable now than it was
then. Limbach got it's start doing VW auto engine overhauls for the
US market nearly 50 years ago. That line of business has been kaput
since the mid-60's as the German economy revved up again after WWII.

[Fred the Red Shirt]

(Ryan Young) wrote in message >...
> (Fred the Red Shirt) wrote in message news:
>
> > Holy crap! How does Limbach do that?
>
> It's a TWO STROKE engine. Compare it to Solo or Rotax engines and it
> looks less remarkable.

Actually, it still looks pretty good by comparison -- one half to one
third the eight for the same horsepower. Another poster has pointed
out that the published weight does not appear to accuratley reflect
the installed weight of a functioning engine.

>
> > According to what I can find
> > on the history of Limbach, the design is based on a VW, but
> > is built from the ground up to be an airplane engine.
>
> THIS Limbach engine has NOTHING in common with a VW engine.

Understood.

--

FF