Dennis,
I think the Lycosaurous people get about ¾ to 1 inch
of improvement with ram air at a couple of hundred mph. That seems consistant
with the airspeed of the air from your blower. Your idea to attach a centrifugal
blower up to the pulley is a good one. You could make it belt driven like the
alternator and with a small pulley, crank it up to about 12K rpm!
Pictures??
Bill B
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Dennis Haverlah
Sent: Monday, February 15, 2010
10:58 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: Air Pump
Bill:
Thanks to my younger brother who was brave enough (use younger brothers for
dangerous stuff) to operate the leaf blower I ran the leaf blower test for the
group. I used a fairly new hand held Echo leaf blower Model PB 251
I "borrowed" from my neighbors hangar.
Specs - 25 cc 2 stroke,
|
Average Air Volume (cfm-pipe)
|
390
|
|
Average Air Volume (cfm-housing)
|
509
|
|
Maximum Air Speed (mph-pipe)
|
145
|
No information on rpm's at these data points were listed. I would guess
that the 2 stroke engines are operated between 6000 and
8000 rpm. but I'd like to have real rpm data.
Four tests were conducted as shown below. Local air pressure was 30.2 in
Baro. - 0.5 in for 1000" = 29.7 in hg. air pressure at field elevation.
Weather was Clear, low humidity and 53 deg. OAT. All tests were at WOT.
Pictures are attached for each test. Note the 180 deg. bend in the Scat
tubing during the (C) test.
The (C) test picture was taken after we had taken the Scat tube but my brother
was holding it in place.
Test condition
Static max. RPM Manifold
Pressure Engine Temp.
(A) Standard intake,
5870
28.9
Barely warm
air filter etc.
(B) W/O air filter &
5660
28.7
Fully
warm
prop blast
(C) Leaf Blower full
5925
29.9
Fully warm
throttle into throttle
body - 180 deg turn.
(D) Same as (A)
5700
29.0
Fully warm
It appears that the blower raised the inlet pressure by 1.2 in Hg. and the
engine rpm increased from 5700 to 5925 rpm.
I needed to turn the mixture knob slightly richer with the blower running to
get max. power.
Also note that the tube feeding the intake had to make a 180 deg. bend just
before the throttle body.
The leaf blower used in this test was the smallest Echo makes.
Their web site lists approximately 15 blowers and the largest is a 63.3 cc 2
stroke as follows:
|
Average Air Volume (cfm-pipe)
|
620
|
|
Average Air Volume (cfm-housing)
|
1240
|
|
Maximum Air Speed (mph-pipe)
|
205
|
My thought is that several blowers are available that probably would provide
the needed blower capacity.
I believe we need a system that is adaptable to using Tracy'c RD-1 drive.
I also believe it is not likely a centrifugal blower can be placed between the
engine and gear box because the spacing between the gear box plate and the
engine is about 2.5 inches and the ring gear is approximately in the middle of
the space. If someone is interested in adding a direct drive blower
why not attach it to the rear of the engine with the centrifugal fan attached
to the crankshaft pulley? The fans from the big blowers
may have enough capacity to work at our crankshaft speeds. If this could
be made to work it would fit the majority of the rotary installations and be an
inexpensive way to add More Power Scotty.
PS I have all the power I need with my DIE intake - if someone can find a way
to build it that may solve most of the power needs.
Dennis Haverlah
Bill Bradburry wrote:
Has
anybody ever tried hooking up a leaf blower to the throttle body inlet and see
what that would do to the static rpm and manifold pressure at WOT?
Bill B