Received-SPF: none
 receiver=logan.com; client-ip=66.196.100.68; envelope-from=casey.gary@yahoo.com
DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws;
  s=s1024; d=yahoo.com;
  h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:MIME-Version:Content-Type;
  b=awxBypVolryfh4/vpYBcz/WhyLYEYsFsUZJZmrM+VTca4l9Km8rdyWqLwAZfJtpi3r3h8SvIxdPGOs5YZns6Hx8RHybB210fkXgLC+jZF2VPVHrItrwBELEXQJFgxJ2vDECZXN8oVBdXWFPmkjDa1mtAblSRAGx1spVl828EKSA=;
Message-ID: <189355.25690.qm@web57501.mail.re1.yahoo.com>
Date: Tue, 14 Apr 2009 05:11:02 -0700 (PDT)
From: Gary Casey <casey.gary@yahoo.com>
Subject: Re: forced landings
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
MIME-Version: 1.0
Content-Type: multipart/alternative; boundary="0-184901205-1239711062=:25690"


--0-184901205-1239711062=:25690
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: quoted-printable

This recent thread has been very interesting and I think it is one of the m=
ost useful purposes of a forum like this.  I detect a few common elements i=
n the various anecdotes:=0A=0A1.  There seems to be a tendency to keep goin=
g in spite of inflight problems.  Is it because the pilot is intimately fam=
iliar with the workings of the machinery and knows it is okay.  Or is it be=
cause he is intimately familiar and thinks it is okay?  Maybe I'm overly co=
nservative, but any deviation from the norm is probably a reason to divert =
to the nearest airport.  I suppose none of us follows this rule completely =
(not even me), but we probably should.  Murphy's law is at work here - any =
change is a bad change, at least 99% of the time.  There also seems to be a=
 tendency to downplay problems found on the ground.  If they will ALWAYS be=
 found on the ground, okay, but is there any chance that failure would not =
be detectable before flight?  Then it's just as serious.=0A=0A2.  Getting k=
nown good parts can be a problem - is the rebuilt water pump really  a good=
 one?  How do we know?  Yes, rebuilt or even new certified aircraft parts a=
re not necessarily good either, but compared to some of the automotive part=
s we are forced to use (I don't think anyone deliberately uses substandard =
parts) they are much more likely to be good.=0A=0A3.  How carefully are the=
 systems put together?  It might take me 30 seconds to put together an elec=
trical connection in my car, but it will take me 5 minutes to do the same c=
onnection in the airplane, including the number of inspections that come af=
ter.  Should an engine be rebuilt in the field?  In a hurry?  I noticed des=
ign problems that encouraged build errors - like the woodruff key that can =
be lost behind the sprocket and not seen.  Is the car engine assembly proce=
ss like an aircraft engine assembly process?  Casual processes breed mistak=
es.  Since non of us are perfect each assembly step should be followed by a=
n independent inspection step, preferably with written documentation.  That=
 takes time.=0A=0A4.  Are the systems tested in every way before being used=
?  I know this isn't always possible, but it should be done to the extent p=
ossible.  Are the cooling systems pressure tested?  Every time they are tak=
en apart?  I don't mean to normal operating pressure, but well beyond - pro=
bably to at least 2 and more like 3 times the maximum pressure.  should the=
 core plugs be replaced with something else?  I noticed there was one core =
plug failure reported - one is enough to change the design from then on, at=
 least in my opinion.  How about the intake systems, especially for boosted=
 engines?  Instead of counting on a bead to hold the hoses together how abo=
ut welding a couple of tabs on the tubes and using a metal link to hold the=
m together, eliminating the need for the hose to do the mechanical support.=
  Are the exhaust systems pressure tested?=0A=0A5.  Is there anything excep=
t fuel and air that can get into the intake system?  Are there any kind of =
nuts, bolts, compressor blades or other pieces that could possibly come loo=
se?  If not, is there a screen that can catch the big ones?  An intercooler=
 serves this function well.=0A=0A5.  Piston engines have hot exhaust system=
s, but rotary engines have HOT exhaust systems.  Hundreds of degrees hotter=
.  Are all the components up to the stress?  Even stainless steel has proba=
bly lost 2/3 of its strength at that temperature.  At that temperature a mu=
ffler isn't just a muffler - it has to be done really well - aricraft muffl=
ers are designed so that internal parts can't block the flow if they come l=
oose (although I've heard of it happening).  It looks like standard passeng=
er car turbos are not up to the task.  Should you use water-cooled turbos? =
 They are not readily available and using one would further increase the co=
mplexity.  What do the racing Mazdas use?=0A=0A6.  Rotary engine exhaust co=
mponents are really HOT (repeating myself, eh?).  To get an idea of how muc=
h potential heat imagine a blowtorch burning a gallon of gasoline every 2 m=
inutes - that would be a huge fire.  That much heat is being contained with=
in the engine compartment.  Obviously all the hot parts and all the parts n=
earby have to be carefully done.  An effective heat shield can be just a sh=
ell, even of aluminum that is between the exhaust and sensitive components.=
  A plastic fuel system component?  No matter how well shielded I don't thi=
nk I would put one in the engine compartment.  What if an exhaust system co=
mponent cracks, especially with a system that is under pressure?  Are all t=
he nearby components protected from the blowtorch that would result?=0A=0A7=
. I was told once that an airplane has only 2 moving parts - the engine and=
 the fuel.  Keeping a continuous flow of fuel is critical.  Automotive fuel=
 pumps, except the turbine variety, are very sensitive to contamination and=
 a small particle can cause them to seize.  Is there an adequate inlet filt=
er?  Not just the coarse screen we use in normal aircraft fuel tanks, but p=
robably the nylon sock that is used in cars.  That filter is there to prote=
ct the pump - nothing else.  Automotive fuel injection systems require fuel=
 that is much cleaner than typical aircraft systems, so standard aircraft g=
ascolators, etc usually won't work except to separate water.  Are the filte=
rs adequate?  do they have adequate reserve capacity?  Standard automotive =
paper fuel filters have a large reserve capacity, but aftermarket sintered =
bronze filters typically don't.  Should there be two filters in the system,=
 the primary with a bypass valve?  Is the filter able to be
 inspected?  If not, how often should it be changed?  I suspect the filters=
 should be changed after the first hour of operation, then after 10 hours a=
nd then every 100 hours.  Not because they are expected to collect that muc=
h dirt, but because they COULD collect that much dirt.  You never know when=
 that big slug of dirt gets purged out of the tank, but is more likely to h=
appen early.  All the systems I've seen use 2 fuel pumps and I would instal=
l a filter downstream from each pump.  Should you be this paranoid of the f=
uel system?  Yup.=0A=0AA very carefully designed and built turbocharged 2-r=
otor at 300 hp (3-rotor 400 hp?) would be true thing of beauty.  I'm sure s=
uch a thing is out there.  Problem is to thoroughly address all the issues =
listed above takes time and money.  Experience is a poor teacher - it gives=
 the test before the lesson.  Other people's experience is, however, useful=
 as then I can put the lesson before the test.=0A=0AI hope this discussion =
has been useful.=0AGary=0A=0A=0A      
--0-184901205-1239711062=:25690
Content-Type: text/html; charset=iso-8859-1
Content-Transfer-Encoding: quoted-printable

<html><head><style type=3D"text/css"><!-- DIV {margin:0px;} --></style></he=
ad><body><div style=3D"font-family:'times new roman', 'new york', times, se=
rif;font-size:12pt"><div>This recent thread has been very interesting and I=
 think it is one of the most useful purposes of a forum like this. =A0I det=
ect a few common elements in the various anecdotes:</div><div><br></div><di=
v>1. =A0There seems to be a tendency to keep going in spite of inflight pro=
blems. =A0Is it because the pilot is intimately familiar with the workings =
of the machinery and knows it is okay. =A0Or is it because he is intimately=
 familiar and thinks it is okay? =A0Maybe I'm overly conservative, but any =
deviation from the norm is probably a reason to divert to the nearest airpo=
rt. =A0I suppose none of us follows this rule completely (not even me), but=
 we probably should. =A0Murphy's law is at work here - any change is a bad =
change, at least 99% of the time. =A0There also seems to be a tendency to
 downplay problems found on the ground. =A0If they will ALWAYS be found on =
the ground, okay, but is there any chance that failure would not be detecta=
ble before flight? =A0Then it's just as serious.</div><div><br></div><div>2=
. =A0Getting known good parts can be a problem - is the rebuilt water pump =
really =A0a good one? =A0How do we know? =A0Yes, rebuilt or even new certif=
ied aircraft parts are not necessarily good either, but compared to some of=
 the automotive parts we are forced to use (I don't think anyone deliberate=
ly uses substandard parts) they are much more likely to be good.</div><div>=
<br></div><div>3. =A0How carefully are the systems put together? =A0It migh=
t take me 30 seconds to put together an electrical connection in my car, bu=
t it will take me 5 minutes to do the same connection in the airplane, incl=
uding the number of inspections that come after. =A0Should an engine be reb=
uilt in the field? =A0In a hurry? =A0I noticed design problems that encoura=
ged
 build errors - like the woodruff key that can be lost behind the sprocket =
and not seen. =A0Is the car engine assembly process like an aircraft engine=
 assembly process? =A0Casual processes breed mistakes. =A0Since non of us a=
re perfect each assembly step should be followed by an independent inspecti=
on step, preferably with written documentation. =A0That takes time.</div><d=
iv><br></div><div>4. =A0Are the systems tested in every way before being us=
ed? =A0I know this isn't always possible, but it should be done to the exte=
nt possible. =A0Are the cooling systems pressure tested? =A0Every time they=
 are taken apart? =A0I don't mean to normal operating pressure, but well be=
yond - probably to at least 2 and more like 3 times the maximum pressure. =
=A0should the core plugs be replaced with something else? =A0I noticed ther=
e was one core plug failure reported - one is enough to change the design f=
rom then on, at least in my opinion. =A0How about the intake systems, espec=
ially
 for boosted engines? =A0Instead of counting on a bead to hold the hoses to=
gether how about welding a couple of tabs on the tubes and using a metal li=
nk to hold them together, eliminating the need for the hose to do the mecha=
nical support. =A0Are the exhaust systems pressure tested?</div><div><br></=
div><div>5. =A0Is there anything except fuel and air that can get into the =
intake system? =A0Are there any kind of nuts, bolts, compressor blades or o=
ther pieces that could possibly come loose? =A0If not, is there a screen th=
at can catch the big ones? =A0An intercooler serves this function well.</di=
v><div><br></div><div>5. =A0Piston engines have hot exhaust systems, but ro=
tary engines have HOT exhaust systems. =A0Hundreds of degrees hotter. =A0Ar=
e all the components up to the stress? =A0Even stainless steel has probably=
 lost 2/3 of its strength at that temperature. =A0At that temperature a muf=
fler isn't just a muffler - it has to be done really well - aricraft muffle=
rs
 are designed so that internal parts can't block the flow if they come loos=
e (although I've heard of it happening). =A0It looks like standard passenge=
r car turbos are not up to the task. =A0Should you use water-cooled turbos?=
 =A0They are not readily available and using one would further increase the=
 complexity. =A0What do the racing Mazdas use?</div><div><br></div><div>6. =
=A0Rotary engine exhaust components are really HOT (repeating myself, eh?).=
 =A0To get an idea of how much potential heat imagine a blowtorch burning a=
 gallon of gasoline every 2 minutes - that would be a huge fire. =A0That mu=
ch heat is being contained within the engine compartment. =A0Obviously all =
the hot parts and all the parts nearby have to be carefully done. =A0An eff=
ective heat shield can be just a shell, even of aluminum that is between th=
e exhaust and sensitive components. =A0A plastic fuel system component? =A0=
No matter how well shielded I don't think I would put one in the engine
 compartment. =A0What if an exhaust system component cracks, especially wit=
h a system that is under pressure? =A0Are all the nearby components protect=
ed from the blowtorch that would result?</div><div><br></div><div>7. I was =
told once that an airplane has only 2 moving parts - the engine and the fue=
l. =A0Keeping a continuous flow of fuel is critical. =A0Automotive fuel pum=
ps, except the turbine variety, are very sensitive to contamination and a s=
mall particle can cause them to seize. =A0Is there an adequate inlet filter=
? =A0Not just the coarse screen we use in normal aircraft fuel tanks, but p=
robably the nylon sock that is used in cars. =A0That filter is there to pro=
tect the pump - nothing else. =A0Automotive fuel injection systems require =
fuel that is much cleaner than typical aircraft systems, so standard aircra=
ft gascolators, etc usually won't work except to separate water. =A0Are the=
 filters adequate? =A0do they have adequate reserve capacity? =A0Standard
 automotive paper fuel filters have a large reserve capacity, but aftermark=
et sintered bronze filters typically don't. =A0Should there be two filters =
in the system, the primary with a bypass valve? =A0Is the filter able to be=
 inspected? =A0If not, how often should it be changed? =A0I suspect the fil=
ters should be changed after the first hour of operation, then after 10 hou=
rs and then every 100 hours. =A0Not because they are expected to collect th=
at much dirt, but because they COULD collect that much dirt. =A0You never k=
now when that big slug of dirt gets purged out of the tank, but is more lik=
ely to happen early. =A0All the systems I've seen use 2 fuel pumps and I wo=
uld install a filter downstream from each pump. =A0Should you be this paran=
oid of the fuel system? =A0Yup.</div><div><br></div><div>A very carefully d=
esigned and built turbocharged 2-rotor at 300 hp (3-rotor 400 hp?) would be=
 true thing of beauty. =A0I'm sure such a thing is out there. =A0Problem is=
 to
 thoroughly address all the issues listed above takes time and money. =A0Ex=
perience is a poor teacher - it gives the test before the lesson. =A0Other =
people's experience is, however, useful as then I can put the lesson before=
 the test.</div><div><br></div><div>I hope this discussion has been useful.=
</div><div>Gary</div><div style=3D"position:fixed"></div></div><br>=0A=0A=
=0A=0A      </body></html>
--0-184901205-1239711062=:25690--