X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imr-db01.mx.aol.com ([205.188.91.95] verified) by logan.com (CommuniGate Pro SMTP 5.4.4) with ESMTP id 5447119 for flyrotary@lancaironline.net; Sun, 18 Mar 2012 20:21:47 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.91.95; envelope-from=shipchief@aol.com Received: from mtaomg-da03.r1000.mx.aol.com (mtaomg-da03.r1000.mx.aol.com [172.29.51.139]) by imr-db01.mx.aol.com (8.14.1/8.14.1) with ESMTP id q2J0L5BT022257 for ; Sun, 18 Mar 2012 20:21:05 -0400 Received: from core-dda001b.r1000.mail.aol.com (core-dda001.r1000.mail.aol.com [172.29.52.1]) by mtaomg-da03.r1000.mx.aol.com (OMAG/Core Interface) with ESMTP id 9C478E000085 for ; Sun, 18 Mar 2012 20:21:05 -0400 (EDT) References: To: flyrotary@lancaironline.net Subject: Re: [FlyRotary] Re: Turbo charger setup In-Reply-To: X-MB-Message-Source: WebUI MIME-Version: 1.0 From: shipchief@aol.com X-MB-Message-Type: User Content-Type: multipart/alternative; boundary="--------MB_8CED37D4EF983AC_14E4_2F65C_webmail-m060.sysops.aol.com" X-Mailer: AOL Webmail 35775-STANDARD Received: from 66.233.22.138 by webmail-m060.sysops.aol.com (64.12.158.160) with HTTP (WebMailUI); Sun, 18 Mar 2012 20:21:05 -0400 Message-Id: <8CED37D4EE679BC-14E4-C3F5@webmail-m060.sysops.aol.com> X-Originating-IP: [66.233.22.138] Date: Sun, 18 Mar 2012 20:21:05 -0400 (EDT) x-aol-global-disposition: G DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20110426; t=1332116465; bh=xd5XcWfr1fP3InJ0CC5g/gR6PGAMcfjZkJvCgjLeANw=; h=From:To:Subject:Message-Id:Date:MIME-Version:Content-Type; b=sjadQ9J/inOTESfuN8rM1rxTI1GLi6XEDy8PwDZz74pKJ4Up9x2iIK3ncFFZim3BY +3vq2SrFxZleecdrohkTXsy2CY5GrJCVuB3QLLEYp/p5SXMM2Z3ngK/Ui1mRhdRPgA XUNwb4B1thvk+mXrYFR+RCcFM7CPo7Wrvm5xSmns= X-AOL-SCOLL-SCORE: 0:2:505545952:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d338b4f667bf1403a This is a multi-part message in MIME format. ----------MB_8CED37D4EF983AC_14E4_2F65C_webmail-m060.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="us-ascii" Well it looks like I may have found the 'loosest' A/R housing available for= myTO4, P trim 65mm turbine. This is A/R 1.30 for an On Center housing. If = .81 is too tight, I have .96, then 1.30. I found these @ turbocharged.com. = with both Turbonetics and Garrett part nos. This is a bolt-on operation, so it won't be time consuming to make this 'tu= ne up' as determined by operational testing. -----Original Message----- From: William Wilson To: Rotary motors in aircraft Sent: Sun, Mar 18, 2012 2:59 pm Subject: [FlyRotary] Re: Turbo charger setup You always want the highest A/R you can get. The charts and quotes for str= eet use are intermittent power, and in an aircraft you need continuous powe= r. Lower A/R makes the turbo not only spin up faster but also makes it les= s efficient, which means more heat dumped into the intake air, more thermal= stress on the turbo and less margin against ignition-related bummers. The charts are also intended for sea level use. Turbos work harder at high= altitude. At 14,000 feet, your turbo is working twice as hard as it would= be at sea level to produce the same HP. The main benefit of a lower A/R is faster spooling time. Almost irrelevant= in an aircraft. High A/R has major benefits. On Sun, Mar 18, 2012 at 2:11 PM, wrote: Kelly; I'm on the Turbonetics chart to size a turbo to an engine application. It's= a matrix chart, which shows To4E-50 STG V .63 A/R as feeding a 4.5 liter e= ngine 10 psi boost and giving 350 HP. My TO4 60-1 P trim @ .81 A/R would be for a 5.0 liter 10 psi boost and 450-= 500 HP. Yet I followed the salesman's advise for fitting. What is it about a rotary= ? I checked the RX-7 site, 60-1 is a common enough application, albeit with a= tighter A/R housing for street driving. When I check the compressor map, I seem to be operating in the lower left h= and corner, low turbine RPM, and not far from the surge line based on estim= ated airflow and pressure ratio. I'm thinking that the exhaust blast of a rotary is much stronger, due to th= e port being wide open, where a piston engine has a poppet valve throttling= the exhaust blast. Perhaps the high exhaust temp coupled with the high ene= rgy exhaust blast requires a bigger turbine to let it out in pulsations rat= her than pressurized flow? I think the Q trim turbine wheel is the 68mm that you have, the P trim that= I have is the smaller 65mm. These measurements being the outside diameter = of smaller exducer part of the turbine wheel. So it would seem to me that your turbine is larger than mine, offering less= restriction to exaust flow, also with a 'looser' A/R turbine housing which= additionally lets exhaust thru with less restriction. Add to that, your 50 series compressor is smaller than my 60-1 compressor, = and pulls less of a load on the turbine. Very interesting. You may get a lower pressure ratio, exhaust pressure : in= take pressure. Less exhaust back pressure for the boost you get. -----Original Message----- From: Kelly Troyer To: Rotary motors in aircraft Sent: Sun, Mar 18, 2012 8:10 am Subject: [FlyRotary] Re: Turbo charger setup My Turbonetics TO4E-50 has the F1-65 turbine wheel but I chose the really= loose 1.15 a/r housing to avoid compressor surge and over speed at hoped for relatively high altitude cruising.......= ...... =20 Kelly Troyer =20 =20 =20 On Sun, Mar 18, 2012 at 7:45 AM, Ed Anderson wr= ote: I understand, some decisions have to be made before you know all the factor= s. An a/r of 0.81 may work fine, just wanted to caution you if it was 0.69= as I truly believe that is a bit on the small size for aircraft applicatio= n - particularly if you do not have any active boost control. =20 Ed From: shipchief@aol.com=20 Sent: Saturday, March 17, 2012 10:14 PM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: Turbo charger setup Ed; While you were answering my post, I was on the Turbonetics site, trying to = recall what was in my 60-1 turbo. I have the 'on center' housing, due to not knowing which way I was going to= face the turbo at the time. This sets the possible A/R choices. The turbin= escome in 2 sizes, F1-62 & F1-65. Of those, the on-center housings' A/R start @ .58, .69, .81 That's it for t= he F1-62 wheel. The F1-65 wheel continues on to .96 and 1.30. I mistankenly said in the last post that the A/R is .61. I'm thinking it's = actaully .81, the loosest choice for the F1-62 wheel, and the median choice= if I have the F1-65 wheel. Now I need to check.=20 I want to set up loose for first flights. I didn't know much about sizing a= turbo when I bought this one, so I called and had the saleman set me up fo= r a 13b turbo jetboat to be run at high altitude lakes with a tight engine = cover....=20 -----Original Message----- From: Ed Anderson To: Rotary motors in aircraft Sent: Sat, Mar 17, 2012 6:41 pm Subject: [FlyRotary] Re: Turbo charger setup I would be hesitant to fly with a 0.68 a/r ratio turbine housing. A small = a/r gives you tremendous (and rapid) boost - that "kick in the seat" sports= car feel. However, at high rpm/power settings several things occur if no = way of controlling the boost. =20 1. The small a/r will tend to overspeed the turbine - especially at altitu= de and can lead to surging. 2. The small a/r will produce a large amount of backpressure and heat from= the turbine housing back to the engine - and add to your heat load - simpl= y because it can not escape as readily as with an larger a/r. 3. The boost pressure may well exceed what your system is designed for 4. You will not produce as much HP at the higher rpm because the overall a= ir mass flow will be less. =20 Most have found that if using an uncontrolled turbocharger that an a/r aro= und 1.0 produces better and safer results. With a Turbonetics 60--1, you s= hould have no problem acquiring a turbine housing closer to 1.0 =20 There are several good books around on turbocharger and a/r selection - mig= ht want to browse through a few. =20 Good luck =20 Ed From: shipchief@aol.com=20 Sent: Saturday, March 17, 2012 6:58 PM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: Turbo charger setup Looks like March 7 was a busy day for this forum! I'm ground running my RV-8 at the airport now. I even did a TAXI TEST to th= e end of the runway and back. I have a Turbo 13b, with a Turbonetics 60-1. I'm at work now, so I can't gi= ve the particulars on the turbo, but someone on this forum told me that my = exhaust housing is pretty tight for not having an intercooler, wastegate or= blow off valve. (.61 A/R??) Last week I ran the engine up while the aircraft was tied down as I have do= ne in the past. But now that I have wings and brakes etc, and at the airpor= t, I've been increasing the power output. I did briefly get a boost reading of 44 " Hg, at about 5000RPM. The oil tem= p was climbing fast as Len says. I pulled back @ 200F, but it went for a fe= w seconds to 206 before it came down. Good thing the oil and water cool wel= l at lower settings. I'm thinking aboout your comments on using excess boost air to operate auxi= lliary equipment. I don't think you can do that in a practical way due to weight and space co= nstraints in the 'engine room'. I can barely fit all my 13b turbo stuff inside an RV-8 cowl, and I don't ha= ve the nose gear version. I could eventually fit a remote wastegate, and an intercooler if needed, bu= t servicing the engine would be difficult, as I would have to remove some l= ayers to get to the core engine. Remember, "Add lightness and simplicate" !! I think I'm getting good power. The CATTO 2 blade prop is a left hand turni= g version of his standard for O-360 Lycoming 180 HP engines. I got it up to= 2280 RPM static. That seems up to 200 RPM higher that RV's are getting. I = just don't know if I can do that for any sustained length of time. I worry about high inlet air temp,and oil temp too.=20 The engine seems to respond well to throttle command while taxi, so as soon= as I get some more wires pulled and the wing tips on, I could try some fas= ter taxi tests... -----Original Message----- From: Mark McClure To: Rotary motors in aircraft Sent: Wed, Mar 7, 2012 9:04 pm Subject: [FlyRotary] Re: Turbo charger setup I am planning on using the turbine of a turbo to spin a generator. I want t= he=20 uffler action. I don't want the added weight/drag of the "Turbo setup" whic= h=20 an be quite large when factoring in all the components.=20 I plan to do most of my flying below 10k so it doesn't make sense to have t= he=20 oosted air. On the other hand - having electronic engine control and electr= onic=20 lying instruments electricity is becoming increasing important to me at all= =20 light regimes. What I fly for a living has a similar electrical demand - so there are two= =20 rimary generators and a third powered off an APU, just in case. But those o= nly=20 rovide electricity to the instruments and mission equipment. The engines ha= ve=20 mall alternators on them for providing primary power to the engine control= =20 nits. Redundancy is the name of the game. So my plan right now is to have an alternator providing power to the EC3 an= d=20 M3. and then a generator providing power to the glass cockpit and avionics.= of=20 ourse the two will be redundant to each other.=20 Then for full redundancy - the glass cockpit has their own backup battery a= nd=20 he airframe battery provides backup for the engine control and monitoring.= =20 I am still very early in the process though - but I believe there is a lot = of=20 nergy to harness out of the exhaust of the rotary. But as you mentioned the= re=20 s something to be said for the muffler action being harnessed for something= =20 seful. Your plan though seems to work in theory - I would probably use that as a = Turbo=20 ormalized setup though. Mark n Mar 7, 2012, at 6:26 PM, Ernest Christley wrote: > On 03/07/2012 06:51 PM, Patrick wrote: > I'm planning to use a turbo on a 20B, primarily as a muffler, but would l= ike=20 o set it for 3-5 psi boost. > A lot of current techniques are based on street car experience, which are= not=20 lways directly applicable to airplanes, ie. no need for rapid throttle resp= onse=20 usually) and run at high % power continuously. >=20 > I'm thinking of a setup modeling refrigeration techniques: >=20 > * Run all exhaust through turbo, no waste-gate, larger A/R > * Compress higher than needed, which makes air very hot > * Run through intercooler, which is more efficient with higher temp delta > * Allow to expand using larger pipe and blow-off valve to regulate > pressure before intake >=20 > The result "should be" cooler intake air at a slight boost. >=20 > What am I missing? >=20 The energy cost of compressing all that air and then throwing it away? =20 hough, like Tracy has said, pressurized air is hard to get on an airplane.= It=20 ouldn't be so bad if you could use it for something. The two things that= =20 pring to my mind are: 1) engine cooling: blow it through a radiator. The drawback is that you'l= l=20 ant more boost on climbout, and that is when you'd want the extra air throu= gh=20 he radiator. 2) exhaust cooling/thrust: push the extra cool air into/around the exhaust= . =20 s I understand it, rotary mufflers die quickly because of a combination of = heat=20 nd sonic pounding. Cooling it will reduce both, and if there might be a sl= ight=20 mount of thrust available if everything is set up just right. =20 -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List= .html - omepage: http://www.flyrotary.com/ rchive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.h= tml --=20 Kelly Troyer Dyke Delta_"Eventually" 13B_RD1C_EC2_EM2 ----------MB_8CED37D4EF983AC_14E4_2F65C_webmail-m060.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="us-ascii"
Well it looks like I may have found the 'loosest' A/R housing availabl= e for myTO4, P trim 65mm turbine. This is A/R 1.30 for an On Center ho= using. If .81 is too tight, I have .96, then 1.30. I found these @ turbocha= rged.com. with both Turbonetics and Garrett part nos.
This is a bolt-on operation, so it won't be time consuming to make thi= s 'tune up' as determined by operational testing.


= -----Original Message-----
From: William Wilson <fluffysheap@gmail.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Sun, Mar 18, 2012 2:59 pm
Subject: [FlyRotary] Re: Turbo charger setup

You always want= the highest A/R you can get.  The charts and quotes for street use ar= e intermittent power, and in an aircraft you need continuous power.  L= ower A/R makes the turbo not only spin up faster but also makes it less eff= icient, which means more heat dumped into the intake air, more thermal stre= ss on the turbo and less margin against ignition-related bummers.

The charts are also intended for sea level use.  Turbos work harder at= high altitude.  At 14,000 feet, your turbo is working twice as hard a= s it would be at sea level to produce the same HP.

The main benefit of a lower A/R is faster spooling time.  Almost irrel= evant in an aircraft.  High A/R has major benefits.

On Sun, Mar 18, 2012 at 2:11 PM, &= lt;shipchief@aol.com> wr= ote:
Kelly;
I'm on the Turbonetics chart to size a turbo to an engine application.= It's a matrix chart, which shows To4E-50 STG V .63 A/R as feeding a 4.5 li= ter engine 10 psi boost and giving 350 HP.
My TO4 60-1 P trim @ .81 A/R would be for a 5.0 liter 10 psi boost and= 450-500 HP.
Yet I followed the salesman's advise for fitting. What is it about a r= otary?
I checked the RX-7 site, 60-1 is a common enough application, albeit w= ith a tighter A/R housing for street driving.
When I check the compressor map, I seem to be operating in the lower l= eft hand corner, low turbine RPM, and not far from the surge line based on = estimated airflow and pressure ratio.
I'm thinking that the exhaust blast of a rotary is much stronger, due = to the port being wide open, where a piston engine has a poppet valve throt= tling the exhaust blast. Perhaps the high exhaust temp coupled with th= e high energy exhaust blast requires a bigger turbine to let it out in puls= ations rather than pressurized flow?
I think the Q trim turbine wheel is the 68mm that you have, the P trim= that I have is the smaller 65mm. These measurements being the outside diam= eter of smaller exducer part of the turbine wheel.
So it would seem to me that your turbine is larger than mine, offering= less restriction to exaust flow, also with a 'looser' A/R turbine housing = which additionally lets exhaust thru with less restriction.
Add to that, your 50 series compressor is smaller than my 60-1 compres= sor, and pulls less of a load on the turbine.
Very interesting. You may get a lower pressure ratio, exhaust pre= ssure : intake pressure. Less exhaust back pressure for the boost you get.<= br>

-----Original Message-----
From: Kelly Troyer <keltro@gmail.com= >
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Sun, Mar 18, 2012 8:10 am
Subject: [FlyRotary] Re: Turbo charger setup

  My Turbonetics TO4E-50 has the F1-65 turbine wheel but I chose = the really loose 1.15 a/r housing to avoid compressor
 surge and over speed at hoped for relatively high altitude = cruising.............
 
Kelly Troyer
 
 
 
On Sun, Mar 18, 2012 at 7:45 AM, Ed Anderson <eanderson@carol= ina.rr.com> wrote:
I understand, some decisions have to be made before= you know all the factors.  An a/r of 0.81 may work fine, just wanted = to caution you if it was 0.69 as I truly believe that is a bit on the small= size for aircraft application - particularly if you do not have any active= boost control.
 
Ed

Sent: Saturday, March 17, 2012 10:14 PM
Subject: [FlyRotary] Re: Turbo charger setup

Ed;
While you were answering my post, I was on the Turbonetics site, tryin= g to recall what was in my 60-1 turbo.
I have the 'on center' housing, due to not knowing which way I was goi= ng to face the turbo at the time. This sets the possible A/R choices. The t= urbinescome in 2 sizes, F1-62 & F1-65.
Of those, the on-center housings' A/R start @ .58, .69, .81 That's it = for the F1-62 wheel.
The F1-65 wheel continues on to .96 and 1.30.
I mistankenly said in the last post that the A/R is .61. I'm thinking&= nbsp;it's actaully .81, the loosest choice for the F1-62 wheel, and the med= ian choice if I have the F1-65 wheel.
Now I need to check.
I want to set up loose for first flights. I didn't know much about siz= ing a turbo when I bought this one, so I called and had the saleman set me = up for a 13b turbo jetboat to be run at high altitude lakes with a tight en= gine cover.... 


-----Original Message-----
From: Ed Anderson <eanderso= n@carolina.rr.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Sat, Mar 17, 2012 6:41 pm
Subject: [FlyRotary] Re: Turbo charger setup

I would be hesitant to fly with a 0.68 a/r ratio tu= rbine housing.  A small a/r gives you tremendous (and rapid) boost - t= hat "kick in the seat" sports car feel.  However, at high rpm/power se= ttings several things occur if no way of controlling the boost.
 
1.  The small a/r will tend to overspeed the t= urbine - especially at altitude and can lead to surging.
2.  The small a/r will produce a large amount = of backpressure and heat from the turbine housing back to the engine - and = add to your heat load - simply because it can not escape as readily as= with an larger a/r.
3.  The boost pressure may well exceed what yo= ur system is designed for
4.  You will not produce as much HP at the hig= her rpm because the overall air mass flow will be less.
 
Most have found that if using an uncontrolled turbo= charger that an a/r  around 1.0 produces better and safer results.&nbs= p; With a Turbonetics 60--1, you should have no problem acquiring a turbine= housing closer to 1.0
 
There are several good books around on turbocharger= and a/r selection - might want to browse through a few.
 
Good luck
 
Ed

Sent: Saturday, March 17, 2012 6:58 PM
Subject: [FlyRotary] Re: Turbo charger setup

Looks like March 7 was a busy day for this forum!
I'm ground running my RV-8 at the airport now. I even did a TAXI TEST = to the end of the runway and back.
I have a Turbo 13b, with a Turbonetics 60-1. I'm at work now, so I can= 't give the particulars on the turbo, but someone on this forum told me tha= t my exhaust housing is pretty tight for not having an intercooler, wastega= te or blow off valve. (.61 A/R??)
Last week I ran the engine up while the aircraft was tied down as= I have done in the past. But now that I have wings and brakes etc, and at = the airport, I've been increasing the power output.
I did briefly get a boost reading of 44 " Hg, at about 5000RPM. T= he oil temp was climbing fast as Len says. I pulled back @ 200F, but it wen= t for a few seconds to 206 before it came down. Good thing the oil and wate= r cool well at lower settings.
I'm thinking aboout your comments on using excess boost air to operate= auxilliary equipment.
I don't think you can do that in a practical way due to weight and spa= ce constraints in the 'engine room'.
I can barely fit all my 13b turbo stuff inside an RV-8 cowl, and I don= 't have the nose gear version.
I could eventually fit a remote wastegate, and an intercooler if neede= d, but servicing the engine would be difficult, as I would have to remove s= ome layers to get to the core engine.
Remember, "Add lightness and simplicate" !!
I think I'm getting good power. The CATTO 2 blade prop is a left hand = turnig version of his standard for O-360 Lycoming 180 HP engines. I got it = up to 2280 RPM static. That seems up to 200 RPM higher that RV's = are getting. I just don't know if I can do that for any sustained length of= time.
I worry about high inlet air temp,and oil temp too.
The engine seems to respond well to throttle command while taxi, so as= soon as I get some more wires pulled and the wing tips on, I could try som= e faster taxi tests...


-----Original Message-----
From: Mark McClure <markmcclure@me= .com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Wed, Mar 7, 2012 9:04 pm
Subject: [FlyRotary] Re: Turbo charger setup

I am planning on using the=
 turbine of a turbo to spin a generator. I want the=20
muffler action. I don't want the added weight/drag of the "Turbo setup" whi=
ch=20
can be quite large when factoring in all the components.=20

I plan to do most of my flying below 10k so it doesn't make sense to have t=
he=20
boosted air. On the other hand - having electronic engine control and elect=
ronic=20
flying instruments electricity is becoming increasing important to me at al=
l=20
flight regimes.

What I fly for a living has a similar electrical demand - so there are two=
=20
primary generators and a third powered off an APU, just in case. But those =
only=20
provide electricity to the instruments and mission equipment. The engines h=
ave=20
small alternators on them for providing primary power to the engine control=
=20
units. Redundancy is the name of the game.

So my plan right now is to have an alternator providing power to the EC3 an=
d=20
EM3. and then a generator providing power to the glass cockpit and avionics=
. of=20
course the two will be redundant to each other.=20

Then for full redundancy - the glass cockpit has their own backup battery a=
nd=20
the airframe battery provides backup for the engine control and monitoring.=
=20

I am still very early in the process though - but I believe there is a lot =
of=20
energy to harness out of the exhaust of the rotary. But as you mentioned th=
ere=20
is something to be said for the muffler action being harnessed for somethin=
g=20
useful.

 Your plan though seems to work in theory - I would probably use that as a =
Turbo=20
Normalized setup though.

Mark


On Mar 7, 2012, at 6:26 PM, Ernest Christley wrote:

> On 03/07/2012 06:51 PM, Patrick wrote:
>> I'm planning to use a turbo on a 20B, primarily as a muffler, but =
would like=20
to set it for 3-5 psi boost.
>> A lot of current techniques are based on street car experience, wh=
ich are not=20
always directly applicable to airplanes, ie. no need for rapid throttle res=
ponse=20
(usually) and run at high % power continuously.
>>=20
>> I'm thinking of a setup modeling refrigeration techniques:
>>=20
>> * Run all exhaust through turbo, no waste-gate, larger A/R
>> * Compress higher than needed, which makes air very hot
>> * Run through intercooler, which is more efficient with higher tem=
p delta
>> * Allow to expand using larger pipe and blow-off valve to regulate
>>   pressure before intake
>>=20
>> The result "should be" cooler intake air at a slight boost.
>>=20
>> What am I missing?
>>=20
> The energy cost of compressing all that air and then throwing it away?=
 =20
Though,  like Tracy has said, pressurized air is hard to get on an airplane=
.  It=20
wouldn't be so bad if you could use it for something.  The two things that=
=20
spring to my mind are:
> 1) engine cooling: blow it through a radiator.  The drawback is that y=
ou'll=20
want more boost on climbout, and that is when you'd want the extra air thro=
ugh=20
the radiator.
> 2) exhaust cooling/thrust: push the extra cool air into/around the exh=
aust. =20
As I understand it, rotary mufflers die quickly because of a combination of=
 heat=20
and sonic pounding.  Cooling it will reduce both, and if there might be a s=
light=20
amount of thrust available if everything is set up just right.
>=20
> --
> Homepage:  http:=
//www.flyrotary.com/



--
Kelly Troyer
Dyke Delta_"Eventually"
13B_RD1C_EC2_EM2

 ----------MB_8CED37D4EF983AC_14E4_2F65C_webmail-m060.sysops.aol.com--