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I recently went on distribution since I am
interested in Rotaries in Race Cars and Aircraft.
Background:
I have an ArrowII and 2 2nd Gen Race Cars with 13 b
Rotaries. (Have a spare engine w/ bad aft Rotor/Housing)
Anyway. I tried but not sure if it is legal so I
removed it, I instaled one of those Gimmic Turbo Flow devices you install in the
intake post the Mass Airflow Sensor. I used it one race and swore I was getting
more power. I would guess as much as 15 HP at the 6-7K Rpm Rage. I
know some are using carbs and do not have the Mass
Airflow/Plenum
to install it but the principle may be the same.
Been tempted to try it out in the IO-360 to see if it makes a
difference.
Be carefull if you do this since the vibs and
pulses of the engine may fatigue the fins and get injested in the
engine.
Disclaimer:
Do at your own risk. We are not liable for anyone
trying this out. Recomend a bench test first.
If anyone tries this out plese let us know th
results.
Thanks.
Mike Zucco
- Air Taxi/Charter Booking
- Aircraft Sales
-
Consulting/Contract Engineering
1-800-879-7985
----- Original Message -----
Sent: Thursday, February 10, 2005 10:12
AM
Subject: [FlyRotary] Re: : Same HP = Same
Air Mass <> same air Velocity II [FlyRotary] Re: Ellison, the missing
piece
Tom,
I don't really think anyone can accurately
make a generalization like that. Certainly a PP 13B (such as power
sports) which reportedly produces 215 HP produces more power than a carb
360 Lycoming. A street ported well tuned 13B will certainly produce
180HP. But, given any two specific engines and depending on how well
their induction/exhaust, etc. are set up, you could have one or the other
producing the greater HP.
But, if someone has specific data that shows the
360 produces more power, then I would certainly like to know about
it.
Ed A
----- Original Message -----
Sent: Thursday, February 10, 2005 9:14
AM
Subject: [FlyRotary] Re: : Same HP =
Same Air Mass <> same air Velocity II [FlyRotary] Re: Ellison, the
missing piece
It's my understanding that NA non-renesis rotary installations
produce less power than 360s, Perry Mick might have a word on this.
Warning
top poster, who cuts the post size down.
A hopothises for your
examination.
A 360 Lyc does not produce the same power as a
rotary.
If true, then the Ellison card may not get enough
air.
If not true, then there is no real reason why the Ellison
cannot feed a
rotary.
Ed, I understand your math, but even if
the local inlet velocity is much
higher, we dont care. the velocities
adverage out to the same, as the
volume of air = velocity * carb
area.
If the velocities are higher, the rotary consumes more air,
and makes more
power.
Eric
----- Original Message -----
From: "Ed Anderson"
To: "Rotary motors
in aircraft"
Sent: Thursday, February 10,
2005 8:31 AM
Subject: [FlyRotary] : Same HP = Same Air Mass <>
same air Velocity II
[FlyRotary] Re: Ellison, the missing
piece
Good question, Tom.
That interpretation did occur
to me. I think the answer depends on your
assumptions, IF using
commonly accepted formulas for calculating air flow vs
rpm and
displacement (and considering both are positive displacement
pumps) -
then the 360 CID lycoming turning 2800 rpm and the rotors in the
rotary
turning 2100 rpm (6300 rpm E shaft) ingest the same total quantity
of
air in one minute - approx 291 CFM. In comparing the two engines,
its
accepted that you compare them over the standard 720deg 4 stroke
cycle -
that means that 4 of the rotary faces have gone through their
cycle in the
same 720 deg of rotation.
But, assuming the
formulas are correct, then they both end up with the same
amount of air
in the engine to create the same HP. I think my math is
correct on the
smaller/unit displacement and longer period of rotation for
the rotary
for the same intake of air. However, in both cases the air flow
is
pulsating and pulsating differently. So if the total displacement
for
the rotary over that 720 deg is less than the Lycoming and the time
it takes
to complete that rotation is slower AND you still ingest the
same amount of
total Air then the only way I can see that happening is
the velocity of the
air in the rotary's intake has to be considerably
higher than in the
Lycoming.
The only other alternative answer I
see if that the commonly accepted
formula for comparing the rotary to
the reciprocating 4 stroke is incorrect
(I got beat about the head
mercilessly by a number of respected rotary
experts challenging that
formula , so I wont' go there again (at least not
now
{:>)).
Air Flow = Total Displacement * RPM/(2 - accounting for
only every other
cylinder sucking on each rev * 1728 (conversion of
cubic inches to cubic
feet) = TD*RPM/(2*1728)
For the 360 CID
Lycoming at 2800 rpm, Air Flow = 360*2800/(2*1728) =
291.66
CFM
Using the commonly accepted notion that a rotary is
equivalent to a 160 CID
4 stroke reciprocating engine because of the 4
faces of 40 CID that complete
there cycle in 720 deg.
For the
160 CID Rotary at 6000 rpm, Air Flow = 160 * 6300/(2*1728) =
291.66
CFM
So if both ingest the 291 CFM and the rotary has less
total displacement
(over 720 deg) then disregarding any of my math on
rotation period
differences you still have to account for why the
rotary can ingest the same
amount of air with less displacement. (Now I
must admit I have my
suspicions about the commonly accepted (racing
approved) formula for the
rotary. However, if my suspicions about the
rotary formula are correct, it
would make the rotary even more
efficient at ingesting air - so I won't go
there {:>)).
If my
logic and calculations are correct then this implies the Ve of
the
rotary is considerably better than the Lycoming and is great than
100%. I
mentioned a few of the reasons why the Ve of the rotary may
indeed be better
in the previous message.
Now, its possible that
the stories about the Ellison not working well on the
rotary is just
that - a story OR there could be a plausible physical reason
as I have
poorly attempted to present.
Ed
----- Original
Message -----
From: Tom
To: Rotary motors in aircraft
Sent:
Wednesday, February 09, 2005 11:54 PM
Subject: [FlyRotary] Re: Same HP
= Same Air Mass <> same air Velocity
[FlyRotary] Re: Ellison, the
missing piece
Ed,
>The rotary has 40 CID displacement
per face and 2 facesx 2 rotors = 4*40
or 160 CID for one rev. So the
rotary has 22% less displacement per
revolution and the longer rotation
period.<
and
>So if the rotary has less displacement
of the sucking component and must
take 25% longer for each revolution.
Therefore the only way it can obtain
an equal amount of air is for the
intake air to have a higher velocity than
the Lycoming
does.<
Isn't 'displacement' equal to the amount of air needing
to be ingested?
So 22% less displacement equates to 22% less air and
the rotarys longer
rotation period gives it more time for air to push
in? And then the
intake air velocity should be
lower?
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