HDTenEightyP/NetNews huggingface dataset:
From: yiannis@ccad.uiowa.edu (Yiannis Papelis)
Newsgroups: rec.aviation.homebuilt
Subject: Re: Cost of owning
Date: 9 Oct 92 02:22:11 GMT
Article-I.D.: ccad.1992Oct9.022211.29290
Organization: CAD-Research, University of Iowa, Iowa City

In some article archie@cory.Berkeley.EDU (Archie Cobbs) writes:
>
> [ Query about ownership costs of homebuilts deleted ]
>
>BTW, I don't intend to deemphasize the generally agreed upon principle
>that one should buy a kitplane primarily because one wants to build
>a plane, not just because one wants to own that plane, or that financial
>concerns are primary... just investigating various aspects of the idea.

Well, I was going to wait before posting my similar thoughts/questions
but this is a good opportunity.  Basically, I am thinking of breaking 
both of the above rules.

RULE 1 , don't buy a kit to build if you want to own.
Can somebody explain why one shouldn't built to own?
I have been seriously thinking about owning and can't 
seem to justify $35-$50 / hour for a warrior/archer/172/whater.  
After being at OSH and reading a lot about homebuilts, 
the idea has crossed my mind that building may be the best way 
to ownership.
A) Am I a dedicated builder (whatever that means) ? no,
B) Do I like to work on machinery only for the pleasure or working on it? no, 
but 
C) I do like to work on machinery with a purpose, i.e., finishing 
something so I can use it, or for fixing it. 
Thus I have decided that the appropriate kit would be one with low
build time (projected 400-700 hours), and relatively low cost (less 
than $25-30K).  I would never start a 2000 hours, 70K kit, since
points A,B don't apply.
To further rationalize that, I have read several posts from people 
saying how much they enjoy helping their mechanic with owner assisted 
annuals.  I may be wrong but I doubt that these people enjoy getting 
dirty hands just for the fun of it, but when it is YOUR plane and 
knowing that gain all this experience there is motivation to 
do things that you would not do otherwise.

Enough mumbling for now, I'll post my cost thoughts related to RULE 2
at another post.
-- 
Yiannis E. Papelis,            - Electrical & Computer Engineering, U of Iowa
Center of Computer Aided Design- Home of the Iowa Driving Simulator & future
e-mail: yiannis@ccad.uiowa.edu - home of the National Advanced Driving Simulator
Newsgroups: rec.aviation.homebuilt
From: venky@thelonious.bellcore.com (G A Venkatesh)
Subject: Re: Subaru Power?
Reply-To: venky@thelonious.bellcore.com (G A Venkatesh)
Organization: Bellcore, Morristown NJ
Date: Thu, 8 Oct 92 17:10:45 GMT

In article <BvrF0x.3AJ@waterloo.hp.com> enns@waterloo.hp.com (Roger Enns) writes:
>By the time Toyota is finished its R&D work, the engine may end
>up costing as much as similar certified engines of today.  I
>would hope that other factors would improve, however.

I am curious about this. What is it about aviation use that requires a
major auto-engine manufacturer with a very well-established record for
innovation to spend huge amounts of money on R&D work before it can
bring out an aviation engine? What are the design bottlenecks and 
compromise points?

venky
Newsgroups: rec.aviation.homebuilt
From: geoff@peck.com (Geoff Peck)
Subject: CHARTER: rec.aviation.homebuilt
Followup-To: rec.aviation.misc
Reply-To: geoff@peck.com
Organization: Geoffrey G. Peck, Consultant, San Jose CA
Date: Mon, 12 Oct 1992 17:23:02 GMT

Welcome to rec.aviation.homebuilt.  This message, and companion messages
like it, will be posted to each of the new rec.aviation.* groups weekly
through the end of November, to allow people to view the charters of each
newsgroup and better understand where to post articles.

The charter of rec.aviation.homebuilt is:

****************************************************************************
*   Selecting, designing, building, and restoring aircraft.  Included in   *
*   this group are a number of different kinds of aircraft:                *
*   builder-designed, plans-built, kit-built, antique and historic, and    *
*   warbirds.                                                              *
****************************************************************************

There are now a thirteen separate subgroups on rec.aviation; if the charter
above doesn't match the content of the article you're posting (or you're
following up), please consider one of the other groups as a more
appropriate forum:

    announce (MOD)    military      piloting        soaring
    answers  (MOD)    misc          products        stories (MOD)
    homebuilt         owning        simulators      student
    ifr 

A common question is "what should I do if an article spans the charters of
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						Geoff
From: laforce@xenon.arc.nasa.gov (Soren LaForce)
Newsgroups: rec.aviation.homebuilt
Subject: re: thrust measurement
Date: 15 Oct 92 22:50:00 GMT
Article-I.D.: xenon.15OCT199215505947
Organization: NASA Ames Res. Ctr. Mtn Vw CA 94035
News-Software: VAX/VMS VNEWS 1.41

The original post mentioned the lack of a "fish scale" as the reason
for not measuring the thrust directly.  You may be able to fudge
a scale with an auto leaf spring.

Mount the leaf spring horizontally, apply a known load and measure
the deflection.

Now mount it vertically and tie the aircraft to it.  Getting the mounts
rigid is going to be the hard part.

For small defections, the spring rate should be pretty linear.

No, I don't know how large a small deflection is, but I'd guess that
an inch or two with a 2 ft. spring would be okay.



--Soren            laforce@xenon.arc.nasa.gov
Newsgroups: rec.aviation.homebuilt
From: tel@cbnews.cb.att.com (thomas.e.lester)
Subject: Re: VW engines
Organization: AT&T
Date: Mon, 12 Oct 1992 17:57:15 GMT

In article <1992Oct6.231703.2928@athena.mit.edu> magnus@athena.mit.edu (Daniel R Risacher) writes:
>Can someone give me a rundown on the characteristics and suitabilty
>for flight of VW engines, such as from a bug?
>

	Well,  I am trying to fly behind one.  There are a LOT of VWs
	out there flying around. Revmaster is basicly a modified VW.
	Also Great plains aircraft supply Steve Bennett 708-464-4178
	sells parts, kits or assembled engines. (all VWs)

	So it is very suitable.  Get a forged crank (not the cast crank)
	Pick a reliable vendor for prop hubs (they bolt directly to the
	crank shaft accesory end).

	Changes required:

	    Different cam to get low rpm torque
	    intake and exhaust manifolds modified.
	    different carbs. (Ellison, or POSA to name 2)

	    Mounting casting normally bolt on the bell housing and
	    hold magneto or ignition device, starter, and alternator.
	    Motor mounts then bolt to this casting.

	    Sizes vary from 1700 cc up.  Mine is 2180
	    This is about the limit on type 1 case (old vw beetle engine)
	    Other conversions use the type 4 for larger displacement.

-- 
	-----------------------------------------------------------------
	Tom Lester				att!cblph!tel
	Sonerai IIL (under TEST)		(614) 860-3259
	N4LX 					(614) 927-8106
From: yiannis@ccad.uiowa.edu (Yiannis Papelis)
Subject: Re: Cost of owning
Organization: CAD-Research, University of Iowa, Iowa City
Date: Fri, 9 Oct 1992 15:09:50 GMT

In some article enns@waterloo.hp.com (Roger Enns) writes:

>Fuel useage - same as comparable powered certified aircraft
>	    - sure, a fast homebuilt will get you to your
>	    destination quicker, but 95% of the time, people fly
>	    local flights anyway, so the point is moot!
>
>100hr/annual is cheaper point removed
>
>Storage is same point removed
>
>Insurance - varies point removed
>
>If anyone else has info to add to above, post away.  The above
>answers are my impressions only, and if I am out of line anywher,
>set me straight!

I guess one important thing to specify before such a discussion
takes place is the type of homebuilt.  Homebuilts vary from ready-to-bolt
together kits that burn 3-5 gals of auto gas an hour, to 
plans only planes that burn 10-15 gals of avgas.

Fuel and engine costs vary dramatically between the two.  Anything
that uses certificated engines with HP>100 that burn avgas,
will cost anywhere from $20 upwards per hour if we look at overhaul
resever and fuel cost.  On the other hand, a two stroke rotax
or even the 912 (BTW has anybody had actual experience with
this engine ?), burning auto gas will cost anywhere between $10-$20/hr.

Of course there is the issue of speed/payload, two seaters are
the norm in kits using these engines, but we can't have it all,
at least this is a choice one can make.


-- 
Yiannis E. Papelis,            - Electrical & Computer Engineering, U of Iowa
Center of Computer Aided Design- Home of the Iowa Driving Simulator & future
e-mail: yiannis@ccad.uiowa.edu - home of the National Advanced Driving Simulator
Newsgroups: rec.aviation.homebuilt
From: karol+@pitt.edu (Filip M. Gieszczykiewicz (fmgst+@pitt.edu))
Newsgroups: rec.aviation.homebuilt
Subject: Help needed (+ a Q or 2)
Date: 10 Oct 92 06:55:06 GMT
Organization: University of Pittsburgh


-- 
-------------------------------------------------------------------------------
DO NOT REPLY HERE. REPLY TO "fmgst+@pitt.edu". THANK YOU. If that doesn't work,
send that e-mail to "fmg@alpha.smi.med.pitt.edu". Looking for donations of 
parts for a home-built airplane: engines, Al tubing, canvas, bolts, prop, etc!
From: mireley@horus.cem.msu.EDU (John Mireley)
Newsgroups: rec.aviation.homebuilt
Subject: Re: Subaru Power??
Date: 12 Oct 92 20:19:45 GMT
Article-I.D.: msuinfo.1992Oct12.201945.24938
Organization: Michigan State University


Comming in on the end of this thread. What's a Subaru engine
worth. I've got an '85, 1800cc with 113K miles on it. The body
is all but gone but the engine runs so well that I've been
holding on to it because it's 4wd.

John Mireley
Newsgroups: rec.aviation.homebuilt
From: adh@cbnews.cb.att.com (andrew.d.hay)
Subject: Re: auto engines
Organization: AT&T
Date: Fri, 9 Oct 1992 11:47:35 GMT
Keywords: CAM100

In article <1992Oct8.174317.21849@selway.umt.edu> cap@selway.umt.edu (Charles A. Smith) writes:
[]
"Anyway, one nice piece on info buried in the CAM100 promo is the fact that
"the typical clearances between parts in the remanufactured Honda engine
"are "opened up" from factory clearances for the auto application.  That is,
[]
"I thought this was nice to know, because I was brought up with the 
""car mentality" that engines need to be assembled to tight tolerances
"in order to go fast, (and therefore be "good").  So, it was somewhat
"counter-intuitive to think that aircraft engines need loose fits
"(to be good).

race engines have larger clearances too.  it _is_ directly because the
pistons et al grow more at higher power, but indirectly because
materials are chosen with regard primarily to strength, whereas in a
car, noise is a big issue so the expansion coefficient is too.

chevy recently changed the pistons on one of their high performance
'crate motors' because buyers who couldn't tell the difference between
piston slap and bearing rap thought the engine was coming apart.

-- 
		+--------------------------------------------------------------+
Andrew Hay	|	I am not an expert,				       |
a_d_hay@att.com	|			 but I play one on the Internet!       |
		+--------------------------------------------------------------+
Newsgroups: rec.aviation.homebuilt
From: enns@waterloo.hp.com (Roger Enns)
Subject: thrust measurements
Date: Thu, 15 Oct 1992 12:02:56 GMT
Organization: HP Panacom Div Waterloo ON Canada
X-Newsreader: TIN [version 1.1.4 PL6]

I am interested in measuring power output of engine/prop
combinations.  Presently I fly an 1835cc VW powered dragonfly.
It has a 52dia x 42pitch prop, and turns 3100 rpm static.  Any
suggestions of a way to measure thrust with simple equipment?  I
am hoping to locate a large 'fish scale' type scale that can be
put in series with a tiedown rope on the tailwheel.  If I am
unable to locate such a thing, I suppose I could use a couple of
bathroom scales behind a fencepost (I know, it's crude!)  I am
not looking for terribly accurate measurements, but more to test
the relative thrust changes with various props, engine changes,
etc.  It would also be neat to hook up some of the other local
VW-powered flyers, to see how the thrusts compare.

I noticed in a recent Sport Av. an Aussie company was using the
Subaru EA81 engine with an AMAX belt reduction.  They reported a
thrust measurement of ~450 lbs.  Do any of you out there have
thrust figures from other low hp aircraft engines, or auto
conversions?  I realize that the numbers will not be directly
comparable, but it should be interesting, none-the-less!

--
Roger Enns (enns@waterloo.hp.com) Panacom Automation Division, HP
C-GIIV Dragonfly, 1979 RX7 13B, 1985 Colt
Newsgroups: rec.aviation.homebuilt
From: leonam@aix02.ecs.rpi.edu ()
Subject: Auto Engines: Montana Coyote
Organization: Rensselaer Polytechnic Institute, Troy NY
Date: Tue, 13 Oct 1992 04:17:40 GMT

A while ago someone suggested several steps/phases towards general acceptance
of an auto engine conversion.  One of these was for a kit plane manufacturer
to design for, test with, and specify, an auto engine for one of their kits.

That said, does anyone have more information about the Montana Coyote than
was contained in last year's _Janes_?  It is a Kitfox-style two seat STOL
airplane, designed to use the 130HP (?) Honda Prelude engine.

Are they shipping kits?  Are any customer-built aircraft flying?  (Is the
prototype flying?)  Do they provide the engines?  What modifications, if
any, are made to the engine?

On a related subject, does anyone know just what the chain of association/
lineage is between Avid, Denney (Skystar?), and Montana Coyote?

				Marc Leonard
				leonam@rpi.edu
From: prang@ssc-vax.boeing.com (Ron Wanttaja)
Newsgroups: rec.aviation.homebuilt
Subject: BMW Power (Was Re: Subaru Power??)
Date: 8 Oct 92 04:23:57 GMT
Organization: Boeing Defense and Space Group, Seattle WA

In article <1992Oct3.114428.704@actrix.gen.nz>, Bruce.Hoult@bbs.actrix.gen.nz writes:
> 
> ... has anyone ever considered using the BMW "K" series motorcycle
> engines in aircraft?
> 
> The 750cc engine is 75 HP and the 1000cc engine is 90 HP.  With the
> fuel injection and engine management computer they automatically
> compensate for altitude up to 17,000 ft.  Based on my experience of
> owning a K100 for five years and over 100,000 Km the engines are
> absolutely 100% rock-solid bullet-proof reliable.
> 
> So what's wrong with them in an aircraft application?

Assuming it's not overly heavy, two things come to mind:  Availability 
and cost.

The VW has achieved the success it has by being cheap and widely
available.  While I do occasionally notice BMW motorcycles (having been a
tank modeller in a previous life) they aren't that common.  And being a bit
rare, their price at the junk yards, etc, are probably pretty high.

Remember, the BMW would require a PSRU (Propeller Speed Reduction Unit) to
bring the output RPMs down to a reasonable level, so one cannot just bolt a
propeller to the output end and fly it.  And if one is developing a PSRU,
why not pick a cheaper, more available engine like the Subaru?

That's not to say it *hasn't* been done.  There's probably someone,
somewhere trying it.  But I'm not aware of anyone.

                                          Ron Wanttaja
					  prang@ssc-bee
					  ...rutgers!uw-beaver!ssc-bee!prang
                                          prang@ssc-bee.boeing.com
From: cap@selway.umt.edu (Charles A. Smith)
Newsgroups: rec.aviation.homebuilt
Subject: Re: Auto Engines: Montana Coyote
Summary: Prelude engines by AVTECH
Date: 14 Oct 92 03:08:38 GMT
Article-I.D.: selway.1992Oct14.030838.12272
Organization: University of Montana

The prelude engine in the prototype Montana Coyote was produced by
     AVTECH 
     P.O. Box 138
     Clancy, MT 59634
     Ph (406)933-5646

I flew to Helena last Fall to see the prototype.  They wouldn't give me
a test ride, but they showed me around and let me watch their promotional
video tape for free.

Since I wasn't allowed to fly it, my impressions are based strictly on 
looking at it, and with talking to the people who run the organization.

This plane is fairly large for a two-seater.  I almost fit in it (I'm 6'5").
It had about the same amount of leg room as an RV-6.  It also has a huge
baggage area.

I was ambivalent about the quality of the parts.  On the one hand, they were
using fairly sophisticated welding fixtures, and the wood wing ribs seemed
to be well made.  On the other hand, many of the weldments seemed to be
too small for the application.  For example, the size of the U-brackets that
attach the landing gear to the frame seemed too small for the loads.
Mind you, I didn't whip out my Cray-1s and do a finite element analysis
on the spot... But in a former existance as a senior engineer at Lockheed,
I used to perform stress and vibration analyses daily, and my opinion
was that that I'd wait for the B model before I'd consider purchasing the
Coyote.

There was an owner from Florida in the shop while I visited.  He was building
his plane under the supervision of the designers.  I later saw a magazine
picture of this plane flying in Florida, so I know that there is at least
one completed kit.

-- 
Cap Smith                 Assistant Prof. of MIS           
cap@selway.umt.edu        University of Montana            
Newsgroups: rec.aviation.homebuilt
From: klingler@pioneer.unm.edu (David Klingler)
Subject: Re: Subaru Power??
Date: Mon, 12 Oct 92 16:18:19 GMT
Organization: Space and Planetary Image Facility

In article <BvuvpD.19I@waterloo.hp.com> enns@waterloo.hp.com (Roger Enns) writes:
>David Klingler (klingler@pioneer.unm.edu) wrote:
>
>: You can find ads for Duncan Aviation in the back of Kitplanes.
>: 
>: Dave
>
>Funny you mentioned Duncan, as I just finished talking with them
>yesterday.  They are sending out an info pack, and putting me on
>a mailing list.  They produce modified mazda rotaries, both
>single and dual rotor engines of HP range 80 to 300.  The single
>rotor engine based on the 12A engine produces 80-150hp depending
>on state of tune.  This sounded quite optomistic, until I was
>told that redline was set at 9000 rpm (GULP!!).  They claim that
>high precision rotor balancing allows them to run continuously at
>red-line, with no premature stationary gear wearout.
>
>In the latest Kitplanes, they had a large add marketing their
>120hp 150lb wet single rotor engine to the BD-5 guys.  Their are
>literally thousands of bd5 kits out there in various stages of
>completion.  They feel that they have the powerplant required to
>get the bd5 into the air.
>
>--
>Roger Enns (enns@waterloo.hp.com) Panacom Automation Division, HP
>C-GIIV Dragonfly, 1979 RX7 13B, 1985 Colt

Yes, the redline on this engine actually turns out to be closer to 
13000 rpm once it's been dynamically balanced.  It sounds wacky at first
until you realize that the rest of the engine is actually running at
about 1/3 that speed (every time I say that I have to scratch my head and
run off to prove it on paper <grin>).

I always took exception to Dan putting his single rotor engine in a BD-5,
even though he's a fine engineer.  I guess if the pilot's light, maybe the
extra 50 doesn't matter, but you'd still want to use 30 or 40 thousandths
wing skins...better maybe to go with a 532.  Does anybody know if Hirth
stayed in business?

Dave

Newsgroups: rec.aviation.homebuilt
From: lark@world.std.com (Lar Kaufman)
Subject: Re: Advantages to radial engines?
Keywords: Radials,
Organization: The World Public Access UNIX, Brookline, MA
Date: Thu, 8 Oct 1992 13:09:52 GMT

It seems that most of the comments on radial engines have been guesses,
not necessarily bad, but I can make some comments from the perspective 
of a (US) FAA-Licensed Airframe and Powerplant mechanic with some 
experience in radial engine maintenance.

Radial engines deliver their power at low RPM.  This is their chief
advantage.  You quickly run into some physical limits in trying to 
deliver horsepower at high RPM; the power must be transmitted through
the propeller blades to move air mass, and the higher the RPM the shorter
the propeller blades must be to prevent their tips from moving at 
trans-sonic speeds, which ruins propeller efficiency.

You could design radial engines with smaller frontal area, especially if
you used a liquid coolant design, but then you would lose your power 
benefits, which derive largely from the long piston stroke.

The main reason that radial engines are not being developed much anymore
(I know of a guy in Texas who markets 3- and 6-cylinder radial homebuild
engines) is a circumstance of machine tool technology development.  It is
very expensive to machine radial engines, which use cam plates for valve
actuation that require very large grinding equipment and high precision 
in grinding the cam plates.  An automotive cam can be ground with high
precision on much smaller and more common equipment.  Because no other
form of machinery has the need to worry about passing power through the
limiting factor of propeller blades with the added concern of weight 
control, the machining equipment for radial engines has a very limited 
market.  (Other applications are happy to add a heavy transmission to 
gear the engine rpm to output needs.)

Don't think radial engine technology is obsolete, either.  Radial engines 
represent some of the most sophisticated of all engine designs.  For 
example, there were 28 cylinder (4 banks of 7 cylinders) turbo-compound
radials that used a mechanical supercharger and then scavenged exhaust
gas velocity by driving a spur gear that input the power directly to the
crankshaft.  Perhaps the most interesting design was the Bristol Centaurus
engine (used in the Hawker Sea Fury, at the end of WWII) which was a 
sleeve-valve design.  Instead of using pushrods and poppet valves, in the 
Centaurus, the piston sleeve rotated, opening and closing intake and 
exhaust ports in a sliding action.  (If I mis-describe the Centaurus 
design, I apologize - I've only read about it and that was long ago.)

Still, I think the radial engine might make a comeback using modern 
computer technology and improved hydraulic technology.  The technique
I would use is to use direct hydraulic actuation of the valves under 
computer control, eliminating the mechanical valve actuation mechanism.

-lar
-- 
Lar Kaufman, Chair, Committee for Common Man  work: 617-893-6562
personal account: lark@world.std.com 
occasional weekend system: lark@whooper.austin.tx.us