Paul,

I use AutoCAD 2010- and have a drawing of my firewall with dimensions.
How do you want it?
DXF, DWG, other format?

Kevin Alderman

DXF is fine Kevin.

Paul Lamar

-- Kevin Alderman wrote:
The horizontal distance center to center of the top holes is 38".
The horizontal distance center to center of the bottom holes is 34.75"
The vertical distance center to center of the holes is 19"

The firewall is 25.875" high in the center, and 43" wide at the center.

The cowling measures 46 inches from the firewall to the end of the cowling.
I can cut this down if needed.
The Wheeler was designed around the IO360, as an engine. Some have
installed
as large as IO 540, but complaints of needing lots of nose up trim (max and
then some) to flare to land are common. Most agree that the IO360 was
marginal on power for the airframe, especially at max gross. If one opted
for the stronger gear and increase in max gross by 300 lbs at times they
complain of long takeoff runs and Cessna 172 performance.

Tracy told me that he has a firewall forward weight of around 400 lbs, and
a
length from firewall to spinner of 39 inches. I am looking for the moment
arm for the IO360 installation as well as a total weight of the IO360, to
compare with the same information for the 20B engine. This should help with
any CG issues before I complete the plane.
I have attached a picture of the engine on my Viking- note the 13 inches
between the engine and the firewall. I would think that this was done to
help move the CG forward. While I have seen engine mounts with room between
the engine and the firewall, not may have this much room. I could put my 10
year old there for a flight if I needed more room in the cockpit!

Let me know if you need anything else, and thanks for the help. I plan to
go
see Tracy in about 2 weeks to learn more.


Kevin Alderman

Got it Kevin. Will work on it in the next couple of days.

==============================****============================**==**======



Here is a preliminary 3D.
Some questions. What is the distance down from the top of
the firewall to the thrust line?
Do you have a cowl yet?

If so I'll try to stuff it under the cowl.

The p-port intake is the same as Mark S's 3 rotor in Austin TX.
Power is pretty much anything you want it to be up to
about 375 HP with out a turbo. Turbo who knows :)

There will be a few minor adjustments on the motor mount positions
a bit later.

Paul

Thanks Paul- I do have a cowl. it measures 46 inches deep, is 34 inches
wide
at the nose, and 24 inches high at the nose. It only has a slight taper. I
figured about 2 inches overlap with the fuse, and the firewall is set back
about 2 inches. This is where the 46 inches came from.

My documentation as far as the thrust line is incomplete. The best I can
get
at the moment is to use known flying planes and photos.
When I scale this photo, and draw a centerline through the cylinders, it
comes out to 4 inches lower than the engine mount bolt at the top.
I also pulled a picture of Buds wheeler- the one that crashed. The pic was
not directly from the side, it was taken from a standing position, however
the same procedure drawing a line through the propeller yields 4 inches
down
from the mount bolt as well.

I can try to get a thrust line distance from the people that bought the
Wheeler factory- but it may take a few days at least to get an answer.

Thanks,

KA

The thrust line looks really high relative to the top of
the cowl. You will need a power bulge down the center about 3 or
4 inches high and a foot wide carried back to the windshield.

Otherwise if the thrust line is lowered 3 or 4 inches that
will limit the prop diameter.

Just a fact of life with the rotary. It is about 14 inches
in diameter give or take a half inch.


Paul Lamar



KA   At this point in time rotary enthusiasts are trying to standardize the
installation of rotary engines in aircraft. This may lead to more standard
components being manufactured for the installation.  Historically there were
several flying examples with the engine mounted   "plugs up" .  In this
configuration the engine assembly is rotated 90 degrees about the eccentric
shaft axis to have the spark plugs on top and the manifolds on the bottom.
With this arrangement the tuned length intake tubes are on the side rather
than over the top of the engine . This allows a higher thrust line and
solved the problem of the distributor and water pump neck on RX-7 engines
sticking up through the cowl.  We now use crank trigger ignition with
electronic fuel injection controlled by Tratcy Crooks flight proven ECM. The
RX-8 has no  distributor and the water pump neck is relocated We now use a
bought engine mounting plate made by Jeff as shown in Paul:s illustration.
It comes drilled for the standard upright installation, however  the
bell housing bolt locations might be rotated 90 degrees on the mount to make
a plugs up installation. The  oil and water radiators are custom
manufactured for either type of installation. We are now seeing side mounted
water radiators and cowl inlet mounted oil coolers which will work with the
plugs up installation as well.  Hopefully if there is a down side to a "plugs
up" installation other people will post a reply with their opinion.

george grimes

Good point George. Kevin will need a cut down a 13B water pump or an RX8
water pump. Mark S is using the low profile RX8 pump on his 3 rotor.

Plugs up is a bad idea as the oil drain backs are designed for upright
mounting. Some guys got away with it. The oil pan becomes complicated
and much heavier than it need be. The oil pick up tube from the oil
pump to the bottom of the pan is longer making priming of the oil pump
marginal. No need for that as the engine with out the distributer and
water pump neck is the same diameter unless you want your spark plugs
sticking up through the top of the cowl :)

Paul Lamar