Today's Message Index:
----------------------
1. 09:08 AM - Re: Mazda rotary (Ben Baltrusaitis)
2. 10:04 AM - Re: Mazda rotary (Scot Stambaugh)
3. 12:13 PM - Re: Mazda rotary (James R. Cunningham)
4. 12:32 PM - Re: Mazda rotary (Tracy Crook)
5. 12:46 PM - Re: Mazda rotary (Tracy Crook)
6. 02:15 PM - Re: Mazda rotary (Scot Stambaugh)
Message 1
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| Subject: | Re: Mazda rotary |
--> Engines-List message posted by: "Ben Baltrusaitis" <ben@gmpexpress.net>
Tracy, thanks for the weight information! I also found your web site. Have you
had any experience with a Mazda engine in an aerobatic biplane? Thanks!
Ben
----- Original Message -----
From: Tracy Crook
To: engines-list@matronics.com
Sent: Sunday, January 26, 2003 11:52 PM
Subject: Re: Engines-List: Mazda rotary
--> Engines-List message posted by: "Tracy Crook" <lors01@msn.com>
> --> Engines-List message posted by: "Ben Baltrusaitis"
<ben@gmpexpress.net>
>
> Tracy,
> Do you have information on what the weight of the Mazda with turbo totals?
>
> Ben
Weight can vary a lot depending on builder choices. The bare block with
water pump of 2 rotor is 180, 3 rotor is 247lb. My total FWF weight on the
three rotor installation on RV-8 is running around 400lb with all
accessories, reduction drive, engine mount, exhaust system, coolant & oil.
No turbo on mine. My 13B RV-4 installation is around 325lb FWF.
Tracy
> ----- Original Message -----
> From: Tracy Crook
> To: engines-list@matronics.com
> Sent: Sunday, January 26, 2003 10:25 AM
> Subject: Re: Engines-List: Mazda rotary
>
>
> --> Engines-List message posted by: "Tracy Crook" <lors01@msn.com>
>
>
> > --> Engines-List message posted by: Nielsenbe@aol.com
> >
> > Do you think that HP rating could go over 300 safely with a super
charger?
> I
> > am really looking for a 350-400HP motor. Thanks, Brad
>
> For that power level you'll need the 20B three rotor engine. Rated
325 -
> 350 HP turbocharged in automotive trim. When supercharged, 400 HP for
> takeoff & climb would be no problem. Continuous power from the Mazda
rotary
> should still be limited to 90 HP per rotor (180 for 13B, 270 for 20B) to
> achieve 2000+ TBO.
>
> Tracy
>
> >
> >
>
>
Message 2
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| Subject: | Re: Mazda rotary |
--> Engines-List message posted by: Scot Stambaugh <sstambaugh@qualcomm.com>
I was just cranking through some numbers:
8,500 RPM / 2.85 = 2982 prop RPM
80" prop diameter * 3.141592(pi) = 251" circumference
251" circumference * 2982 RPM = 748,482 inches/minute prop tip speed
748,482 = 708.8mph tip speed on a typical length 2-blade prop used for 250
to 300 hp engines.
It seems like you will have to slow things down a little more that 2.85:1
to get the tips out of the supersonic speed range. I am a Electronic
Engineer by profession and know very little about Aero/Astro Engineering so
please tell me if I am missing something fundamental in the above
calculations/assumptions.
thanks,
Scot Stambaugh
At 06:28 PM 1/24/2003, you wrote:
>--> Engines-List message posted by: "Tracy Crook" <lors01@msn.com>
>
>
> > --> Engines-List message posted by: "Terry Watson" <terry@tcwatson.com>
> >
> > Tracy, or anyone else:
> >
> > What is the aircraft conversion potential of the new higher-horsepower
>Mazda
> > rotary design that's going into the RX8? I understand it has
>substantially
> > more power than the 13B.
> >
> > Terry
>
>Potential is huge! engine & all systems weighing less than an O - 320 but
>producing 250 HP. I am salivating at the thought of obtaining one. Only
>problem is that they develop that 250 HP at 8500 - 9000 RPM. I am designing
>a new version of my gear reduction drive (RD-1C) with a ratio of 2.85 : 1 to
>use with this engine.
>
>Tracy Crook
>
>
> >
> >
>
>
Message 3
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| Subject: | Re: Mazda rotary |
--> Engines-List message posted by: "James R. Cunningham" <jrccea@bellsouth.net>
Don't forget that tip speed is a vector. You have computed only the
rotational component of the tip speed. You need to square that, square
the airspeed, add the two squares together and then take the square root
of the sum to obtain the actual tip speed. The speed you calculated
below, is too slow.
All the best,
JimC
Scot Stambaugh wrote:
>
> --> Engines-List message posted by: Scot Stambaugh <sstambaugh@qualcomm.com>
>
> I was just cranking through some numbers:
>
> 8,500 RPM / 2.85 = 2982 prop RPM
>
> 80" prop diameter * 3.141592(pi) = 251" circumference
>
> 251" circumference * 2982 RPM = 748,482 inches/minute prop tip speed
>
> 748,482 = 708.8mph tip speed on a typical length 2-blade prop used for 250
> to 300 hp engines.
>
> It seems like you will have to slow things down a little more that 2.85:1
> to get the tips out of the supersonic speed range. I am a Electronic
> Engineer by profession and know very little about Aero/Astro Engineering so
> please tell me if I am missing something fundamental in the above
> calculations/assumptions.
>
> thanks,
>
> Scot Stambaugh
>
> At 06:28 PM 1/24/2003, you wrote:
> >--> Engines-List message posted by: "Tracy Crook" <lors01@msn.com>
> >
> >
> > > --> Engines-List message posted by: "Terry Watson" <terry@tcwatson.com>
> > >
> > > Tracy, or anyone else:
> > >
> > > What is the aircraft conversion potential of the new higher-horsepower
> >Mazda
> > > rotary design that's going into the RX8? I understand it has
> >substantially
> > > more power than the 13B.
> > >
> > > Terry
> >
> >Potential is huge! engine & all systems weighing less than an O - 320 but
> >producing 250 HP. I am salivating at the thought of obtaining one. Only
> >problem is that they develop that 250 HP at 8500 - 9000 RPM. I am designing
> >a new version of my gear reduction drive (RD-1C) with a ratio of 2.85 : 1 to
> >use with this engine.
> >
> >Tracy Crook
> >
> >
> > >
> > >
> >
> >
>
Message 4
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| Subject: | Re: Mazda rotary |
--> Engines-List message posted by: "Tracy Crook" <lors01@msn.com>
Scot, your observations are correct.
Design of virtually anything is always a compromise. The 2.85 : 1 ratio is
dictated by what gears are available (I use Ford C6 & E4D transmission
parts). If cost were no object, I'd have custom gears made. But then
almost no one could afford to buy the reduction drives. It's another case
of perfect being the enemy of good.
But actually, 2.85 : 1 works out pretty well. I anticipate operating the
RX-8 engine at 8000 RPM max to obtain 266 HP. Without the handicap of all
the automotive accessories, emissions controls, restrictive exhaust systems,
etc, the engine should produce 250 HP at only 7500 RPM. Add to this the
fact that faster planes like the RVs don't usually have 80 inch props, (more
like 74") then the prop tip speeds become more reasonable. Even if it
means going to 3 blades instead of two, I feel this is a reasonable design
compromise.
For an engine that weighs less than an O - 360, makes as much power as an
O - 540, and costs half as much as an O - 320, you have to give up
something. And in this case, it's not reliability. Using a shorter, three
blade prop seems a small price to pay.
Tracy Crook
----- Original Message -----
From: "Scot Stambaugh" <sstambaugh@qualcomm.com>
Subject: Re: Engines-List: Mazda rotary
> --> Engines-List message posted by: Scot Stambaugh
<sstambaugh@qualcomm.com>
>
> I was just cranking through some numbers:
>
> 8,500 RPM / 2.85 = 2982 prop RPM
>
> 80" prop diameter * 3.141592(pi) = 251" circumference
>
> 251" circumference * 2982 RPM = 748,482 inches/minute prop tip speed
>
> 748,482 = 708.8mph tip speed on a typical length 2-blade prop used for 250
> to 300 hp engines.
>
> It seems like you will have to slow things down a little more that 2.85:1
> to get the tips out of the supersonic speed range. I am a Electronic
> Engineer by profession and know very little about Aero/Astro Engineering
so
> please tell me if I am missing something fundamental in the above
> calculations/assumptions.
>
> thanks,
>
> Scot Stambaugh
>
>
> At 06:28 PM 1/24/2003, you wrote:
> >--> Engines-List message posted by: "Tracy Crook" <lors01@msn.com>
> >
> >
> > > --> Engines-List message posted by: "Terry Watson"
<terry@tcwatson.com>
> > >
> > > Tracy, or anyone else:
> > >
> > > What is the aircraft conversion potential of the new higher-horsepower
> >Mazda
> > > rotary design that's going into the RX8? I understand it has
> >substantially
> > > more power than the 13B.
> > >
> > > Terry
> >
> >Potential is huge! engine & all systems weighing less than an O - 320
but
> >producing 250 HP. I am salivating at the thought of obtaining one. Only
> >problem is that they develop that 250 HP at 8500 - 9000 RPM. I am
designing
> >a new version of my gear reduction drive (RD-1C) with a ratio of 2.85 : 1
to
> >use with this engine.
> >
> >Tracy Crook
> >
> >
> > >
> > >
> >
> >
>
>
Message 5
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| Subject: | Re: Mazda rotary |
--> Engines-List message posted by: "Tracy Crook" <lors01@msn.com>
Aerobatic? I can't remember a flight I've made in the past five years when
I didn't get upside down at least once :-). I don't have inverted oil
system but I don't do sustained negative G maneuvers anyway. Adding
inverted oil system would be no harder than it is on a Lycoming. I'd start
with a Christen inverted oil system if I were doing it.
The EFI already works upside down so no need for any change there. Just
make sure you have a flop tube pickup in you fuel tank.
Tracy
> --> Engines-List message posted by: "Ben Baltrusaitis"
<ben@gmpexpress.net>
>
> Tracy, thanks for the weight information! I also found your web site. Have
you had any experience with a Mazda engine in an aerobatic biplane? Thanks!
> Ben
> ----- Original Message -----
> From: Tracy Crook
> To: engines-list@matronics.com
> Sent: Sunday, January 26, 2003 11:52 PM
> Subject: Re: Engines-List: Mazda rotary
>
>
> --> Engines-List message posted by: "Tracy Crook" <lors01@msn.com>
>
>
> > --> Engines-List message posted by: "Ben Baltrusaitis"
> <ben@gmpexpress.net>
> >
> > Tracy,
> > Do you have information on what the weight of the Mazda with turbo
totals?
> >
> > Ben
>
> Weight can vary a lot depending on builder choices. The bare block with
> water pump of 2 rotor is 180, 3 rotor is 247lb. My total FWF weight on
the
> three rotor installation on RV-8 is running around 400lb with all
> accessories, reduction drive, engine mount, exhaust system, coolant &
oil.
> No turbo on mine. My 13B RV-4 installation is around 325lb FWF.
>
> Tracy
>
> > ----- Original Message -----
> > From: Tracy Crook
> > To: engines-list@matronics.com
> > Sent: Sunday, January 26, 2003 10:25 AM
> > Subject: Re: Engines-List: Mazda rotary
> >
> >
> > --> Engines-List message posted by: "Tracy Crook" <lors01@msn.com>
> >
> >
> > > --> Engines-List message posted by: Nielsenbe@aol.com
> > >
> > > Do you think that HP rating could go over 300 safely with a super
> charger?
> > I
> > > am really looking for a 350-400HP motor. Thanks, Brad
> >
> > For that power level you'll need the 20B three rotor engine. Rated
> 325 -
> > 350 HP turbocharged in automotive trim. When supercharged, 400 HP
for
> > takeoff & climb would be no problem. Continuous power from the
Mazda
> rotary
> > should still be limited to 90 HP per rotor (180 for 13B, 270 for
20B) to
> > achieve 2000+ TBO.
> >
> > Tracy
> >
> > >
> > >
> >
> >
>
>
Message 6
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| Subject: | Re: Mazda rotary |
--> Engines-List message posted by: Scot Stambaugh <sstambaugh@qualcomm.com>
Sounds like very reasonable compromises and clear design considerations.
thanks,
scot
At 12:30 PM 1/27/2003, you wrote:
>--> Engines-List message posted by: "Tracy Crook" <lors01@msn.com>
>
>Scot, your observations are correct.
>
>Design of virtually anything is always a compromise. The 2.85 : 1 ratio is
>dictated by what gears are available (I use Ford C6 & E4D transmission
>parts). If cost were no object, I'd have custom gears made. But then
>almost no one could afford to buy the reduction drives. It's another case
>of perfect being the enemy of good.
>
>But actually, 2.85 : 1 works out pretty well. I anticipate operating the
>RX-8 engine at 8000 RPM max to obtain 266 HP. Without the handicap of all
>the automotive accessories, emissions controls, restrictive exhaust systems,
>etc, the engine should produce 250 HP at only 7500 RPM. Add to this the
>fact that faster planes like the RVs don't usually have 80 inch props, (more
>like 74") then the prop tip speeds become more reasonable. Even if it
>means going to 3 blades instead of two, I feel this is a reasonable design
>compromise.
>
>For an engine that weighs less than an O - 360, makes as much power as an
>O - 540, and costs half as much as an O - 320, you have to give up
>something. And in this case, it's not reliability. Using a shorter, three
>blade prop seems a small price to pay.
>
>Tracy Crook
>
>----- Original Message -----
>From: "Scot Stambaugh" <sstambaugh@qualcomm.com>
>To: <engines-list@matronics.com>
>Subject: Re: Engines-List: Mazda rotary
>
>
> > --> Engines-List message posted by: Scot Stambaugh
><sstambaugh@qualcomm.com>
> >
> > I was just cranking through some numbers:
> >
> > 8,500 RPM / 2.85 = 2982 prop RPM
> >
> > 80" prop diameter * 3.141592(pi) = 251" circumference
> >
> > 251" circumference * 2982 RPM = 748,482 inches/minute prop tip speed
> >
> > 748,482 = 708.8mph tip speed on a typical length 2-blade prop used for 250
> > to 300 hp engines.
> >
> > It seems like you will have to slow things down a little more that 2.85:1
> > to get the tips out of the supersonic speed range. I am a Electronic
> > Engineer by profession and know very little about Aero/Astro Engineering
>so
> > please tell me if I am missing something fundamental in the above
> > calculations/assumptions.
> >
> > thanks,
> >
> > Scot Stambaugh
> >
> >
> > At 06:28 PM 1/24/2003, you wrote:
> > >--> Engines-List message posted by: "Tracy Crook" <lors01@msn.com>
> > >
> > >
> > > > --> Engines-List message posted by: "Terry Watson"
><terry@tcwatson.com>
> > > >
> > > > Tracy, or anyone else:
> > > >
> > > > What is the aircraft conversion potential of the new higher-horsepower
> > >Mazda
> > > > rotary design that's going into the RX8? I understand it has
> > >substantially
> > > > more power than the 13B.
> > > >
> > > > Terry
> > >
> > >Potential is huge! engine & all systems weighing less than an O - 320
>but
> > >producing 250 HP. I am salivating at the thought of obtaining one. Only
> > >problem is that they develop that 250 HP at 8500 - 9000 RPM. I am
>designing
> > >a new version of my gear reduction drive (RD-1C) with a ratio of 2.85 : 1
>to
> > >use with this engine.
> > >
> > >Tracy Crook
> > >
> > >
> > > >
> > > >
> > >
> > >
> >
> >
>
>
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