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1. 08:03 AM - Re: Kit Planes accident and reliability article (Hinde, Frank George (Corvallis))
2. 08:17 AM - Re: Kit Planes accident and reliability article (Hinde, Frank George (Corvallis))
Message 1
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| Subject: | Kit Planes accident and reliability article |
All good there..I guess my point was that shoddy workmanship was the reason
for these failures, but there maybe other similar failure modes in differe
nt engine packages.
Of course my experiences have made me biased too, but I guess getting parts
rebuilt from an aviation shop with years of experience just seems like a v
ery good idea when compared with a guy in a cylinder head shop who shrugs h
is shoulders when you look at him in disbelief at locktited/knurled valve g
uides as he says.."Thats how we always do it"..Yes and its just tried to ki
ll me for the third time!
Also the engine package is very application specific..I.e for a relatively
slow airplane like the Zodiac then an 8k Soob conversion is probably a pret
ty good deal (assuming you can be sure to avoid the shoddy workmanship...I.
e go to Ram Performance).
For a higher horsepower (and slicker airframe) a 180-200HP conversion will
cost very close to what a an experimental Lycoming clone will cost..Add to
that the higher fuel consumption due to the drag of radiators (thats my pos
ition until it has been proved otherwise) and the auto converstion really d
oes not look like it represents any savings at all..I mean lets assume an e
ngine life of 2000 hours and an extra gallon per hour due to the extra drag
of the automotive conversion...Well thats $8000 over the life of the motor
...Now that significantly reduces any cost savings of the automotve convers
ion.
Certainly I am not arguing the modern engine itself in its intended applica
tion (i.e a car) is less reliable than an a Lycoming...But when you convert
everything, deal with all the computers, figure out a vapour lock proof fu
el system, add a reduction drive...well you can see that the converted engi
ne is a very different animal than it was when firmly planted on the ground
.
As for me, if I was building another Zodiac....I't put a Soob in it..Better
the devil you know right?...:)
Gentlemen..it has been a pleasure working with you all in the past!
Frank
________________________________
From: owner-stratus-list-server@matronics.com [mailto:owner-stratus-list-se
rver@matronics.com] On Behalf Of Don Walker
Sent: Sunday, August 31, 2008 8:04 PM
Subject: RE: Stratus-List: Kit Planes accident and reliability article
Frank,
to be honest, the reason we suffered the failures we did with the valve
guides is that these engines were rebuilt by people unfamiliar with aviatio
n. Rhiner had the work done by another shop during the last of his tenure a
nd that system followed until you and I started making waves.
The valves guides failed since they were Knurled guides. After mine fail
ed twice, I got another old soob and rebuilt it, but used the original guid
es, which were never taken out, and just transfered the redrive and intakes
systems to the new engine. This engine has done very well without using gu
ides with shoulders, etc.
What I am saying is that these engines were shoddy work and done withou
t an understanding of aviation...knurled guides...that is the sickening par
t to me. An original soob, or a soob with stock guides would do well if pro
perly installed...though the shoulders and better materials is a plus for s
ure. don
LarryMcFarland <larry@macsmachine.com> wrote:
Hi Frank,
The Kit Planes article is extremely well done and I don't contradict
what you said below. Their data only said internals of automotive
conversions and
perhaps carburetor systems were better represented than type certified
engines. The facts are not disputed, that cooling, ignition, fuel
systems and redrives
will be problematic so long as the user builder isn't totally aware of
what a good installation requires. It does take a little more education
for a Subaru
owner than for a Lyc or Cont because certified engines don't allow much
room for variation. If the owner does the study, I believe the Subaru
is capable of being
a better engine in cost per hour for the average builder. It's about
$8K for a Subaru now and $20+K for a Jabaru or 912 and much much more
for the TC engines.
I'm not an engine guy either Frank, but I learned a lot from the
difficulties you experienced and the travails you'd posted before me.
I also made mistakes, but none that cost any serious money or downtime
thanks to you.
Very best regards,
Larry McFarland 601HDS at www.macsmachine.com
Hinde, Frank George (Corvallis) wrote:
>
> Hmmmm.....
>
> I think that's a little bit of a sweeping statement there Larry..If you r
emember I suffered three valve guide failurs in my Subaru conversion..I wou
ld say that as I had only 400 hours that was an appalling failure rate..Fou
rtunately I was able to re-engineer the package and fix a fundamental flaw
in the suppliers product, but that's only because I have a lot of experienc
e in this area.
>
> Most folks I fear have little clue about such things, or about killer vap
our lock, how to engineer a cooling system etc.
>
> If somebody with my experience can have such troubles (and who bought an
engine package to avoid having to mess with the conversion itself) then the
average Joe has no chance.
>
> I would be interested to read the article because anecdotal evidence woul
d appear to dissagree with your statement.
>
> Hopefully the market will weed out poor engine conversions...But at a pot
entially great cost.
>
> Don't get me wrong there are one or two really good auto conversions, but
they certainly are not cheaper on the initial installation cost (comparing
an Eggenfelner Soob with an experimantal Lycoming clone) and if you add th
e extra cooling drag of a water cooled engine vs an aircooled (at least on
a fast airplane) then fuel consumption is going to be worse....Ok that last
statement is fiercely debated...:)
>
> Where auto conversions really shine is in rebuild costs are much less..Bu
t is that really a big factor in the overall cost of an airplane?..I person
ally doubt it.
>
> Frank
>
> 601 HDS Soob 400 hours
> RV7a 330 hours IO360 WAAY faster and better MPG than the Zodiac...:).Also
runs on pump gas
>
> -----Original Message-----
> From: owner-stratus-list-server@matronics.com [mailto:owner-stratus-list-
server@matronics.com] On Behalf Of LarryMcFarland
> Sent: Saturday, August 30, 2008 8:56 AM
> To: zenith-list; stratus-list
> Subject: Stratus-List: Kit Planes accident and reliability article
>
> -->
>
>
> Hi Guys,
> The October issue of Kit Planes has a fine article on accidents and
Message 2
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| Subject: | Kit Planes accident and reliability article |
Bryan,
You are talking about 400mph airplanes here (and as A Brit I am very proud you
guys chose to use OUR engine in YOUR airplane..:)..). This is VERY different to
a 100mph Zodiac.
But also, those radiator installs had thousands of hours of development work behind
them. Sure, we MAYBE able to improve the drag characteristics of a radiator
but the plain fact is nobody has done it.
There is not one properly engineered radator install out there that you can buy.
Now part of this is the design of the airplane itself..Generalll you need a
long duct both in front and behind the rad..The engine placed on the nose of the
airplane is not conjucive to this.
In the Zodiac its probably a moot point, a little bit of extra drag is not going
to make much difference, but a fast airplane like a an RV or Lanceair that extra
drag will be significant.
So not arguing improvements could be made, but automotive suppliers have very little
incentive to do so.
Personally I would love to see automotive conversions on faster airplanes, but
right now for that particular application it really offers no clear advantage
over a Lycosaurus.
Frank
Do not archive
-----Original Message-----
From: owner-stratus-list-server@matronics.com [mailto:owner-stratus-list-server@matronics.com] On Behalf Of Bryan Martin
Sent: Sunday, August 31, 2008 2:13 PM
Subject: Re: Stratus-List: Kit Planes accident and reliability article
--> <bryanmmartin@comcast.net>
A properly engineered water cooled installation should have considerably less cooling
drag than an air-cooled installation. North American was able to get enough
thrust out of the cooling system for the P-51 to almost cancel out the cooling
drag. Other manufacturers who just slapped a big radiator behind the prop
didn't fare nearly as well. Another example of good cooling design is the Spitfire.
Neither the Spitfire nor the Mustang ever had any problems with overheating
in flight. The problem is that most aircraft aren't designed around a water
cooled engine so compromises have to be made to get adequate cooling.
On Aug 31, 2008, at 1:21 PM, Hinde, Frank George (Corvallis) wrote:
> (Corvallis)" <frank.hinde@hp.com>
>
>
> Don't get me wrong there are one or two really good auto conversions,
> but they certainly are not cheaper on the initial installation cost
> (comparing an Eggenfelner Soob with an experimantal Lycoming clone)
> and if you add the extra cooling drag of a water cooled engine vs an
> aircooled (at least on a fast
> airplane) then fuel consumption is going to be worse....Ok that last
> statement is fiercely debated...:)
>
--
Bryan Martin
N61BM, CH 601 XL,
RAM Subaru, Stratus redrive.
do not archive.
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