In my plane the largest radiator I could fit under the cowl and not under
the engine was an MR2 radiator. Its core size is 26 x 12. What radiators
are the high HP p port guys using? Primarily I would be looking for
size,material and number of cores. If you used a remote fill container with
the radiator cap, did you buy it or make it?
Aluminum welding isn't easy to learn and even more difficult to have the
equipment to do it in some places, so an off the shelf version would be
nice. However, if you cant get one find a way to make it. That requires
dimensions. Next time you are in the hangar, take a pic of the cooling
system and send it over. Notes help, and a measuring tape in the picture is
worth its weight in gold. KA The ideal core is out of a Dodge pickup.
Probably overkill. With our asymmetric motor mount and motor plate the rad
core will fit vertically on the plug side of the engine. The turbo will
also fit with the asymmetric motor mount.
I don't recommends using the stock Cont. mount. The motor mount is the
last thing to be designed. First one fits all the major components. Then
one builds the mount around them. A good 3D program like Rhino is
essential. The stock cowl shown will work fine, No room under the engine
with a nose gear for the rad core. Several airplanes are flying with this
arrangement. Nothing new here.
I still need the dims on the firewall hard points to finish this.. A
stock Corvette pressure can works well. http://tinyurl.com/d6p3s9p Paul
Lamar I will confirm the dims of the mounting points today after the sun
comes up. The stock Cont mount has a few more bars than some of the other
mounts, but
the only ones that are in the way are the ones for the retractable nose
gear brackets.
I am holding out hope that I will be able to make the retracts work at
some point.
Now that I have the radiator mock up in the cowl, the tubes aren't in the
way much at all.
I cant get a Dodge truck radiator in the cowling- 14 inches high is about
the max and be able to close the hood. The MR2 rad gives me a few inches
either end, and room above and below tor get my hands around it.
KA
The Toyoto MR2 would not be large enough. That is a low continuous
power engine compared to the Dodge pickup. The Dodge rad can be cut
down as you will need new aluminium end tanks anyway. The tubes run side
to side so no problem cutting it down. What is the height of the firewall?
The cowl on the Wheeler is extra long.
One of the things that must be addressed is the heat from the turbo
affecting the strength of the motor mount. Brian is dealing with that
issue now.
I can incorporate the retracts into the front MM design.
There is plenty of room behind the eng for the nose gear.
If you still have the Viking gear send me some pictures.
I may be able to use it.
------------------------------------
I found some pictures. A retract nose gear is a piece of cake.
The engine is the main mass at the front of the airplane and it can react
the
nose gear loads directly like a Questair Venture does.
Also very similar to a Bonanza.
http://www.rotaryeng.net/mm-instruct.html
Paul Lamar
Paul, beautiful piece of work explaining the engine mount details.
Milo
Thanks Milo
Paul Lamar
its not the length of the radiator, its the height. The curves of the
cowling limit the height of the radiator or force it to be too close to the
engine. And, with the sharp radius on the lower front of the cowling,
around 30 inches is the max length of the radiator. The radiator that I
mentioned is for the turbo MR2, all aluminium which has a higher
transmission ratio than a brass or alloy radiator.
As far as retracts go, its not the nose that is giving me trouble, its my
thin wings. If I fold the gear up into the wings, literally 6 inches is
hanging out from under the bottom of the wing. I turned the wings upside
down, cut the hole for the wheel well and installed another rib. I then
installed the retracts every which way I could think of- oleo toward the
wing upper surface, toward the ground, rotating 30 degrees, etc. It just
wont fit. The Wheeler wings for the first and second generation are too
thin to get the wheels in. The newest version has a thicker wing, and with
tiny tires they fit. But with those little bitty tires, I wouldn't want to
land on a grass strip.
The engine mount already has the mounts, pivot points, etc. to install the
retractable nose gear. It will be a lot of additional work to make it
steerable though. And, the viking nose gear has a history of making poor
pilots planeless, so to think about retracts on the nose only wouldnt be
the way to go. One other problem is where the gear tucks up into the
fuselage. On the viking there was a pocket for the nose wheel. On the
wheeler there isn't. I would have to cut away part of the bottom in the
center including some of the firewall. On the inside this happens to be
where the rudder mechanism is located. The viking rudder pedals had their
pivots up front, but all the linkages was just in front of the seats to get
around the nose wheel cut out. An alternative would be to fold the gear up
until it touches the fuse and hold it there, but this would still be a lot
of drag.
I received the rest of the PSRU parts yesterday and will soon start
installing it on the plane. Then I can precisely locate the cowling and
then start to mount other items permanently that go inside the cowling.
KA
All rads are aluminium now a days. Back about 5 years ago everybody had
cooling problems before we got a handle on it. It takes about 600 cubic inches
of rad to cool a 200 HP rotary. For a 250 HP turbo it takes about 750.
That is for a 3 inch thick rads. Knock off 25% for a 1 inch thick rad.
BTW Here is a simple way of looking at cooling drag as it affects rad thickness.
Lets say we have a 1 square foot cooling scoop. If the scoop was completely
blocked the drag would be full dynamic pressure. Dynamic pressure at 200 MPH
is 100 pounds per square foot. 200 MPH is about 300 feet per second.
Therefore the HP consumed is 300 x 100 or 30,000 pound foot per second.
550 pound foot per second is one HP so our blocked scoop is consuming
54 HP. If the scoop was totally open and the air went straight through with
no restriction the drag and HP consumed would be near zero. Only a little
bit from skin friction. Thinner rads have less restriction but more frontal area
for the same volume. The job of the diffusers is to increase the area of the
duct. If you increase the area of a duct the air velocity is reduced but
the volume of the air passing through is the same. Since drag is air velocity
squared.....
By now you can see where I am going with this.
This is why Kays & London wrote:
"the use of highly compact [efficient] surface geometries is that
the resulting core shapes are characterized by large flow frontal
area and short flow lengths for the gas-flow path".
Just a nose retract like a Long EZ would reduce your overall drag.
Paul Lamar
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