RV6A down in Seattle area

"Dale Alexander" wrote in message
...
And of course you drive them at 65-75% power all the time, right? That
would be like driving everywhere with the throttle application just short
of passing gear...all the time. That would be like drivng up the worlds
longest hill...all the time. Sure pal...

As a matter of fact, a lot of automotive and light truck based engines are
subjected to just that sort of service in marine applications, generators,
etc. They seem to tolerate it quite well in a properly designed
installation.

Give me a break. I've replaced more in-tank fuel pumps on GM's in the last
six months than I care to remember. GMs' have probably had more recalls
than the next three manufacturers combined. Next you'll tell me that
rotaries are the next hot ticket item.

Dale Alexander

As far as the rotaries go, you seem to have missed that whole sequence by at
least ten years.

Other than the obvious poor fuel efficiency, which was probably no worse
than two-cycle engines, I really can't comment--because I never saw an
installation (or plans for one) with properly designed cooling.

Peter

"Peter Dohm" wrote

As far as the rotaries go, you seem to have missed that whole sequence by
at least ten years.

Other than the obvious poor fuel efficiency, which was probably no worse
than two-cycle engines, I really can't comment--because I never saw an
installation (or plans for one) with properly designed cooling.

There has been one at OSH for all of the 4 or 5 times I was there, that
seemed to get along quite well. Tracy Crook -
http://www.rotaryaviation.com/
--
Jim in NC

"Morgans" wrote in message
...

"Peter Dohm" wrote

As far as the rotaries go, you seem to have missed that whole sequence by
at least ten years.

Other than the obvious poor fuel efficiency, which was probably no worse
than two-cycle engines, I really can't comment--because I never saw an
installation (or plans for one) with properly designed cooling.

There has been one at OSH for all of the 4 or 5 times I was there, that
seemed to get along quite well. Tracy Crook -
http://www.rotaryaviation.com/
--
Jim in NC

Thanks Jim,

I could probably squirm out by saying that it hadn't actually seem it, which
is true, but the fact is that I simply forgot and I stand corrected. Tracy
Crook, and his work are quite famous (especially in the RV community) and I
would really like to take a look at his installation to see just how much
radiator he needed in a tractor installation with plenty of ram air--a good
look with the pilot/builder present is sure to be informative and I would
like to hear his opinion of other installations. I would be especially
curious what he thinks about pushers with ducted intakes because consistent
cooling has been somewhat elusive in southern Florida.

Peter

"Peter Dohm" wrote

I could probably squirm out by saying that it hadn't actually seem it,
which is true, but the fact is that I simply forgot and I stand corrected.
Tracy Crook, and his work are quite famous (especially in the RV
community) and I would really like to take a look at his installation to
see just how much radiator he needed in a tractor installation with plenty
of ram air--a good look with the pilot/builder present is sure to be
informative and I would like to hear his opinion of other installations.

His installation that I saw (he has since put a newer engine in) used two GM
air conditioner condensers as radiator, and strangely enough, that is a
pretty popular choice. I don't know if he started that trend, or if he got
the idea from someone else. I have also seen Ford 3.8's and Chevy 4.3's in
airplanes with the same setup.

As I recall, he used them parallel in the cooling line, and had them placed
directly behind the standard cowl twin inlets.

The other popular radator placements I have seen use the radiator back at
the firewall, with the top of the engine baffled off from the bottom, and
had the cooling air go past the top of the engine, through the radiator,
then into the engine compartment, then out the normal lower outlet.

I would be especially curious what he thinks about pushers with ducted
intakes because consistent cooling has been somewhat elusive in southern
Florida.

Indeed. Use of NACA type of inlets have usually failed, badly. The type of
scoop that works the best is a P-51 type of scoop, mounted above or below
the engine.

The key is to have the air flow through the radiator first, then past the
engine, (or directly out into the air) because if the air picks up engine
heat then goes through the radiator, it is sure to fail.

The other key to this type of arrangement is getting the outlet into a good
low pressure area. I have seen some that looked like the twin round inlets,
only they are the outlets. They are indeed tricky to get right, it seems.
--
Jim in NC

"Morgans" wrote in message
...

"Peter Dohm" wrote

I could probably squirm out by saying that it hadn't actually seem it,
which is true, but the fact is that I simply forgot and I stand
corrected. Tracy Crook, and his work are quite famous (especially in the
RV community) and I would really like to take a look at his installation
to see just how much radiator he needed in a tractor installation with
plenty of ram air--a good look with the pilot/builder present is sure to
be informative and I would like to hear his opinion of other
installations.

His installation that I saw (he has since put a newer engine in) used two
GM air conditioner condensers as radiator, and strangely enough, that is a
pretty popular choice. I don't know if he started that trend, or if he
got the idea from someone else. I have also seen Ford 3.8's and Chevy
4.3's in airplanes with the same setup.

As I recall, he used them parallel in the cooling line, and had them
placed directly behind the standard cowl twin inlets.

I think that you may mean heater cores, which would have a larger water
passage, but I am hoping for a look if I go to SnF this year. The layout
that you mention is very similar to one that I have seen used successfully
on a Subaru conversion in a KR2--although I don't know who may have done it
first.


The other popular radator placements I have seen use the radiator back at
the firewall, with the top of the engine baffled off from the bottom, and
had the cooling air go past the top of the engine, through the radiator,
then into the engine compartment, then out the normal lower outlet.

I would be especially curious what he thinks about pushers with ducted
intakes because consistent cooling has been somewhat elusive in southern
Florida.

Indeed. Use of NACA type of inlets have usually failed, badly. The type
of scoop that works the best is a P-51 type of scoop, mounted above or
below the engine.

The key is to have the air flow through the radiator first, then past the
engine, (or directly out into the air) because if the air picks up engine
heat then goes through the radiator, it is sure to fail.

I think that you are essentially correct, although I don't know how much of
the problem is engine compartment heating and how much is poorly organized
airflow if the air must flow past the engine.


The other key to this type of arrangement is getting the outlet into a
good low pressure area. I have seen some that looked like the twin round
inlets, only they are the outlets. They are indeed tricky to get right,
it seems.

Tricky seems to be an understatement, especially when using airports that
demand an estended ground run!

--
Jim in NC

Peter

"Peter Dohm" wrote

I think that you may mean heater cores, which would have a larger water
passage, but I am hoping for a look if I go to SnF this year.

No, I'm pretty sure they were AC condensors.

The layout that you mention is very similar to one that I have seen used
successfully on a Subaru conversion in a KR2--although I don't know who
may have done it first.


Tricky seems to be an understatement, especially when using airports that
demand an estended ground run!

I have never understood why a person would not include an electric fan to
pull air through the radiator, when necessary ground runs do not provide
enough air flow.

That would be 5 pounds well spent, I would think. I will include one if my
installation ever takes place, unless someone could come up with a reason
not to include it.
--
Jim in NC

"Morgans" wrote in message
...

"Peter Dohm" wrote

I think that you may mean heater cores, which would have a larger water
passage, but I am hoping for a look if I go to SnF this year.

No, I'm pretty sure they were AC condensors.

The layout that you mention is very similar to one that I have seen used
successfully on a Subaru conversion in a KR2--although I don't know who
may have done it first.


Tricky seems to be an understatement, especially when using airports that
demand an estended ground run!

I have never understood why a person would not include an electric fan to
pull air through the radiator, when necessary ground runs do not provide
enough air flow.

That would be 5 pounds well spent, I would think. I will include one if
my installation ever takes place, unless someone could come up with a
reason not to include it.
--
Jim in NC

I have wondered about the exact same thing, and am leaning toward the same
solution.

Peter

Peter Dohm wrote:
"Morgans" wrote in message
...
"Peter Dohm" wrote

I could probably squirm out by saying that it hadn't actually seem it,
which is true, but the fact is that I simply forgot and I stand
corrected. Tracy Crook, and his work are quite famous (especially in the
RV community) and I would really like to take a look at his installation
to see just how much radiator he needed in a tractor installation with
plenty of ram air--a good look with the pilot/builder present is sure to
be informative and I would like to hear his opinion of other
installations.
His installation that I saw (he has since put a newer engine in) used two
GM air conditioner condensers as radiator, and strangely enough, that is a
pretty popular choice. I don't know if he started that trend, or if he
got the idea from someone else. I have also seen Ford 3.8's and Chevy
4.3's in airplanes with the same setup.

As I recall, he used them parallel in the cooling line, and had them
placed directly behind the standard cowl twin inlets.

I think that you may mean heater cores, which would have a larger water
passage, but I am hoping for a look if I go to SnF this year. The layout
that you mention is very similar to one that I have seen used successfully
on a Subaru conversion in a KR2--although I don't know who may have done it
first.

The other popular radator placements I have seen use the radiator back at
the firewall, with the top of the engine baffled off from the bottom, and
had the cooling air go past the top of the engine, through the radiator,
then into the engine compartment, then out the normal lower outlet.

I would be especially curious what he thinks about pushers with ducted
intakes because consistent cooling has been somewhat elusive in southern
Florida.
Indeed. Use of NACA type of inlets have usually failed, badly. The type
of scoop that works the best is a P-51 type of scoop, mounted above or
below the engine.

The key is to have the air flow through the radiator first, then past the
engine, (or directly out into the air) because if the air picks up engine
heat then goes through the radiator, it is sure to fail.

I think that you are essentially correct, although I don't know how much of
the problem is engine compartment heating and how much is poorly organized
airflow if the air must flow past the engine.

The other key to this type of arrangement is getting the outlet into a
good low pressure area. I have seen some that looked like the twin round
inlets, only they are the outlets. They are indeed tricky to get right,
it seems.

Tricky seems to be an understatement, especially when using airports that
demand an estended ground run!

--
Jim in NC

Peter


Actually, they are GM *evaporator* cores, the heat exchanger that's
mounted in the dash to cool the air.

I've seen his installation on average about once a year for the last 10
years, & watched it evolve over the years from carbs to injection & from
the original 13B to the Renesis engine core. I think that if you ask
him, he'd tell you that they were 1. available, 2. affordable, 3. fit in
the stock cowl, 4. actually turn out to be fairly close to the right
thickness for a relatively high speed homebuilt like an RV-x.

His work is sublime pragmatism. A marketing exec would go into cardiac
arrest just looking at it, but everything is carefully engineered to be
good enough with nothing extra. For instance, the intake plenum is a
fiberglas covered plywood box. But inside the box are details (which he
openly describes to anyone who will listen) that almost everyone ignores
when they build an intake system (and almost no one else achieves his
performance). Which brings us back to my earlier posts about too many
people not doing their homework before doing a conversion project.

Charlie

"Charlie" wrote

Actually, they are GM *evaporator* cores, the heat exchanger that's
mounted in the dash to cool the air.


Yep, I knew that about 2 minutes after sending the post. Condensor would
be the little radiator out next to the car radiator. Oh well, at least
someone knew what I meant! g

I've seen his installation on average about once a year for the last 10
years, & watched it evolve over the years from carbs to injection & from
the original 13B to the Renesis engine core. I think that if you ask him,
he'd tell you that they were 1. available, 2. affordable, 3. fit in the
stock cowl, 4. actually turn out to be fairly close to the right thickness
for a relatively high speed homebuilt like an RV-x.

All true, but he plain likes rotary engines, too. Maybe goes past like a
littke bit, even!

His work is sublime pragmatism. A marketing exec would go into cardiac
arrest just looking at it, but everything is carefully engineered to be
good enough with nothing extra.

Yep. Kinda' like the JB Weld around the fitting for the cooling fluid into
the _evaporator_ cores.
I definitely has a sound to it, screaming by on a low pass, though!
--
Jim in NC