I have decided to use a turbo p-port 13b on my Wheeler. I have the
core engine completed and sitting on the engine mount at the
moment. Before I make the engine mounts, etc. and start laying out
the rest of the engine compartment I need to confirm a couple of
things-
My plan is to have around 250HP or so (maybe a little more) and
end up with a modest boost at take-off power. The boost will be
controlled to maintain this power level if desired up at altitude.
1. The first question is about the intake runners. Is it necessary
to maintain the 18 inch length of the runners even if I run a
turbo? Or, can I run the turbo discharge into a plenum with just
enough tubing to make it in to the plenum after the throttle plates?
2. Is sufficient heat available from the cooling water (read
heater core) to provide cabin heat at high altitudes in cold
weather. Here in FL heat wasn't much of an issue other than having
too much of it, but in the Carolinas in the winter I have seen OAT
below 0 at 12,500'. That's cold. I remember that the rotary uses
the oil as a means to remove waste heat, so would it be a better
idea to use oil as a means to heat the heater core for cabin heat?
3. There has been a lot of discussion about turbos and getting
them to live longer than an hour or 2 with the rotary. I have found
2 types of turbos that are described as "continuous running"- one
has ceramic bearings and the other has a "floating journal".
Advice here would be helpful- the turbo I select will determine the
exhaust header selection. A model number or something would be a
great start.
Kevin Alderman
On the intake length the 18 inches are still an advantage with a
turbo as during the low boost phase there is still a breathing
advantage. That translates to slightly lower fuel burn per HP generated.
If you send me a sketch of the fire wall I'll do a 3D layout of
the motor mount and turbo installation.
The KIS shown has a higher thrust line than most aircraft so the position
of
the thrust line relative to the top of the firewall is important
for 18 inch runner clearance.
Paul Lamar
I am using the Viking mount that I have- the Viking is 4 inches narrower
than the Wheeler but that was a minor modification. The problem at
the moment is the thrust line and the cowl that came with the plane.
When the engine is centered up I only have 1 inch or so between it
and the cowl on top. I measured my Connie and the only way it would
have worked is because the high point is at the extreme rear at the
mags. The mags would have been about 1/2 inch from the cowl. I can
get more clearance by lowering the thrust line, not my first choice.
The later Wheelers have a conventional tail not the cruciform tail
that I have- and the thrust line is about 2 inches lower. I assume
that the tail had something to do with placement of the thrust line.
The only recurring complaint about the CT Wheeler is that it has low
tail authority on landing. Moving the propwash and thrust line down
might make this worse.
The good news is that my cowling is 46 inches long- which gives me
about a half acre under the cowl for the engine. The 13B looks quite
small naked under there at the moment. I have the plane blocked up
at the spar, and with the engine sitting in place I still need 100
lbs just to get a neutral CG. With that info, I need to get as much
of the engine done as possible
(hanging parts on it) so that I can get my WB right. Which means
turbo, etc. is up on the list.
I have reservations about using the cooling air ducted into the cockpit.
The cowl flaps that you showed are under the plane at the exhaust-
and any exhaust leakage particularly under the cowl would be
directed into the cockpit. My ventilation is through NACA vents on
either side of the plane well away from any exhaust. The air from
these vents will be ducted through air vents to the passengers, or
can be diverted through an RX8 heater core mounted behind the panel.
Kevin Alderman
Yes I can see that you have less clearance under the the cowl than
a KIS cruiser. That rules out the 18 inch up and over intake
runners. I assume you are using the Viking nose gear as well. Moving
the thrust line down without moving the entire motor down would
affect the prop clearance as well of course.
Your scheme of using a beam to pick up the front connie mounts will
work well with a custom oil pan. That will put the engine/GB/prop CG
right over the front connie mounts. The rear connie mounts can be ignored.
We used to use that and called it a Schertz beam. It was patterned after
the QuestAir
Venture mount. Here is some shots of the QA set up.
I assumed you were going to use a simple 180 degree side exhaust
out of the turbo but a RX8 heater core will also work well.
I can still do a 3D of your set up if you give me a few dims such
as the distance of the thrust line down from the top of the firewall
and the dims between motor mount points.
Paul Lamar
I will be out of town (read away from the airplane project) for a
week, I can document the dims on the mount when I get back. I have
decided not to use the Viking nose gear- after a LOT of work I just
cant get the retractable gear to work in the wings, the Wheeler wing
is too thin. So, I will use the Wheeler factory fixed gear setup
with the castering nose gear. The Wheeler has no provisions for
steerable nose gear, as it was designed to be steered with
differential braking. So, to avoid lots of extra work I went back to
the original. I was willing to adapt the plane for retractable gear,
but not just for the nose.
Do you have a known thickness for a header for the turbo that will work
for this application? I have found several made from SS, but I want
to make sure that they will not burn through in the air.
Back to the intake runners, I do have plenty of room to route the intake
runners up and rearward (toward the firewall) and keep them in the
range of 18".
Kevin Alderman
The stock 2nd gen will work but most used ones are already cracked.
The sharp machined edges need to be radius-ed with a die grander.
V out the cracks and weld them up. It will last 5 years.
Paul Lamar
What is the welding procedure you recommend? There is high Nickel arc rod or
preheat and Oxy Acetylene weld with cast rod that I know of. I know some
cylinder blocks welded in non structural areas with the nickel rod. In the
exhaust, I would expect cracking beside the weld.
Dale Davies
I am no expert on the subject. Larry Childs welded a front end housing for
me and he says the secret is... heat it in an oven before welding and make sure it
cools very slowly.
Paul Lamar
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