Serious STOL fun

"Bertie the Bunyip" wrote

In fact, I've heard the opposite, that the Jabirus seldom make it past 500
hours and often a lot less before needing a rebuild..

Yeah, I've heard that is about right for the early ones.

The scuttlebutt is that they learned some lessons, and redesigned some
things, and that their power and reliability is now much, much improved.
--
Jim in NC

"Morgans" wrote in
:


"Bertie the Bunyip" wrote

In fact, I've heard the opposite, that the Jabirus seldom make it
past 500 hours and often a lot less before needing a rebuild..

Yeah, I've heard that is about right for the early ones.

The scuttlebutt is that they learned some lessons, and redesigned some
things, and that their power and reliability is now much, much
improved.

Well, they'r nice looking little thnkgs and the power to weight is really
impressive!

I hope they do establish themselves There's a big market for them...

Bertie

You need to do some reading over in rec.aviation.homebuilt. *A guy over
there will tell you that a VW can not do that many HP continuous, and for
good reason, I think.

Try this link, http://bobhooversblog.blogspot.com and read "The Christmas
Engine" (I think that is the name of the article)
--
Jim in NC

Well, I didn't say it could.

I've read that too, and I don't doubt it.

You need to do some reading over in rec.aviation.homebuilt. *A guy over
there will tell you that a VW can not do that many HP continuous, and for
good reason, I think.

Try this link, http://bobhooversblog.blogspot.com and read "The Christmas
Engine" (I think that is the name of the article)
--
Jim in NC

Well, there's always a guy somewhere on the internet that will tell
you something for free.

I don't like articles about car engines that try to draw analogies to
sex. That doesn't tell you jack-all from a technical standpoint.
Absolutely worth zero except yah, if you build an engine yourself you
can expect to maintain it yourself, and you'll have to put in a lot of
hours -- it's like changing diapers. Not quite the same, in my view. I
like working on engines but surely did not like changing diapers. If
you're the builder, and you're the one who does the maintenance on the
engine, you're going to be working on it regardless of what kind it
is.

Technical matters demand a technical approach, not weak analogies. The
kind of technical writing on the internet that I respect is the kind
of stuff William Wynn puts out about Corvairs, for instance.

Try this link, http://bobhooversblog.blogspot.com and read "The Christmas
Engine" (I think that is the name of the article)
--
Jim in NC

Okay, found the Christmas Engine.

Much better!

Yes, but show me a standard VW head that does not melt down at more than an
honest 50 HP continuous, and I'll change my tune. *I don't think I'll have
to buy a new songbook anytime soon! *They just can not get rid of any more
waste heat than that.
--
Jim in NC

Hoover write's about thrust being more important that HP. That jibes
with other stuff I've read.

The christmas engine blog sounds like he's doing all this direct
drive?

Can you really get max HP out of an automobile engine at lower RPMs
required for a prop not to spin too fast? Don't you pretty much have
to have a PSRU to match max auto engine HP to sub-sonic prop RPM?

Well, okay this should be asked over on homebuilts. Anyway the OP was
all about having fun in low n slow. I think these guys are
outrageously low n slow.

wrote

Hoover write's about thrust being more important that HP. That jibes
with other stuff I've read.

The christmas engine blog sounds like he's doing all this direct
drive?

Since HP (and therefore heat) is the limiting factor with VW, you can easily
hit the maximum thermal HP and still keep the engine at low prop RPM's. No
need to rev fast with a PSRU and be limited to part throttle to keep it
cool. It would just mean more weight to haul around.

Can you really get max HP out of an automobile engine at lower RPMs
required for a prop not to spin too fast? Don't you pretty much have
to have a PSRU to match max auto engine HP to sub-sonic prop RPM?

No, if you go direct drive with most auto engines, you are being satisfied
with lower HP levels than would be possible with a reduction unit. It still
would be a sizeable amount of HP, but less HP per pound than airplane
engines, since auto engine blocks are usually so massive.

You look at an engine torque and HP graph produced from a dyno, and where
the torque curve crosses the HP curve is usually close to the ideal speed to
run the engine for maximum power and thrust. At those RPM's at wide open
throttle, the HP per weight is in line with conventional airplane engines,
and probably a little better.

Many times, you will see people run a little lower RPM than that
intersection, for noise, fuel economy, and for engine longetivity.

Well, okay this should be asked over on homebuilts. Anyway the OP was
all about having fun in low n slow. I think these guys are
outrageously low n slow.

Yep. If you want to learn more, there are many people over there that know
their stuff, and still quite a few that are anti auto engine maniacs. Like
always, you sort through it and use what you can.
--
Jim in NC

"Bertie the Bunyip" wrote

Well, they'r nice looking little thnkgs and the power to weight is really
impressive!

I hope they do establish themselves There's a big market for them...

Yep. I hope the world beats a path to their doors.

Have you seen the 8 cylinder that they are about to put out?

Can you imagine how that thing must sound? Sweet! I'll bet it is smooth,
too.
--
Jim in NC

"Morgans" wrote in
:


"Bertie the Bunyip" wrote

Well, they'r nice looking little thnkgs and the power to weight is
really impressive!

I hope they do establish themselves There's a big market for them...

Yep. I hope the world beats a path to their doors.

Have you seen the 8 cylinder that they are about to put out?

Well, pics of it in SA or kitplanes or something.

Can you imagine how that thing must sound? Sweet! I'll bet it is
smooth, too.


It's nice to see the future is being assured somehow!

I was looking at one of the Aussie Rotecs. Still might, but there's a new
Czech radial that also looks interesting. OTOH I might just keeep the old
radial!

Bertie

Yeah, an automotive conversion really doesn;t appeal to me for a lot of
reasons. Some VW designs are realyl fun though! And breaths there a
pilot with a soul so dead as to not turn and look at a nice model A
poswered Piet?

------------------------------------------------------------------------

There are any number of modern industrial engines, some weighing less
than the Model A, that produce an honest 65 to 85 hp at 1800 to 2200
rpm.

-R.S.Hoover