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0-235 vs Turbo Subaru

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jcorner(at)shaw.ca
Guest

Posted: Tue Dec 05, 2006 9:14 pm Post subject: 0-235 vs Turbo Subaru

This is maybe a problem that most of you wish you had..... and to  

many the answer might be very obvious.



I have 1 each of the above two engines, one I purchased and the other  

I received on a debt owing.  For this question assume that installed  

cost is about the same.



Installed weights are about the same...... and one of these engines   

is going into a Kitfox Model 5, I just can't seem to make a final  

decision and stick with it.



The Sube has more power 150+ vs 115 for the Lyc



The Lyc  has a longer proven history of reliability, and perhaps a  

little easier to install and maintain.



The S5 Kitfox will be equipped for night flying, i don't expect any  

hard IFR, floats may come later.



One week I am convinced that I will install the Sube, next the Lyc.



Have to make up my mind very soon, pre-cover inspection coming right up.



Which one should I install?  Comments appreciated.



Jim



PS:  I currently fly a Model 2, 582 s/n 575 just over 1100 hrs.

Glenn Horne

Joined: 10 Jan 2006
Posts: 96

Posted: Wed Dec 06, 2006 5:36 am Post subject: 0-235 vs Turbo Subaru

The Lyc. No question about it. There are only two engine to fly behind.Lyc. 

7 Cont.

GG

---

barefootpilot(at)comcast.
Guest

Posted: Wed Dec 06, 2006 5:38 am Post subject: 0-235 vs Turbo Subaru

Jim,

I have the Lycoming on a model 5 and have been very happy with it. Lots of 

torque to turn a big prop which gives great take off and climb performance. 

Cruise speed is good also (130 mph at 5.2 gph) For floats I think the Lyc 

might be the better choice.

The nice things about the subie are that it can burn auto gas and you can 

install an inflight adjustable prop. For my taste though, the Lycoming is a 

much simpler setup with fewer things to go wrong and you can get parts and 

service on it anywhere.

good luck,

Cliff



 	  Quote: 	
		  

 One week I am convinced that I will install the Sube, next the Lyc.



 Have to make up my mind very soon, pre-cover inspection coming right up.



 Which one should I install?  Comments appreciated.



 Jim



 PS:  I currently fly a Model 2, 582 s/n 575 just over 1100 hrs.

eskflyer(at)lvcisp.com
Guest

Posted: Wed Dec 06, 2006 6:14 am Post subject: 0-235 vs Turbo Subaru

I dont know who brain washed you but , your wrong . There are many engines 

to fly behind . They are all mechanical and will break at some point . That 

said I have flown behind 2 strokes and never had a engine out  . I have 

flown behind continentals and have had rods thrown threw the case . I have 

flown behind subbies and never had a problem . ahve flown behind Lycomings 

and had mags fail . HMMMMM whats the better engine , each to there own i 

guess.



John Perry

---

ruebd(at)skymail.csus.edu
Guest

Posted: Wed Dec 06, 2006 8:41 am Post subject: 0-235 vs Turbo Subaru

Jim:



	Direct drive and a single cooling system, maintainability

'anywhere' would favor the Lycoming.  Assuming that both engines are in

good serviceable condition, I know which one I would rather be flying

behind when, say approximately 100 miles west of Denver at 13,500 ft.

(for a brief period).  I would definitely vote for the Lycoming at that

time.  

	The "real ones" are often criticized for being behind the times,

but the truth is that they are tried and true, and have the advantage of

being designed from the ground up as aircraft engines, and have

benefited from years of improvement, and advances of material science.

Since aircraft engines experience a very different operational profile

than car engines, putting out 100% power at every takeoff, and then

65-75% continuously thereafter, until descent and landing, all of their

parts were designed with that operation profile in mind, from the

crankshaft to the valves.  They are often compared to tractor engines,

and with good reason, since a tractor also needs to put out a high

percentage of its power continuously.  Tractor engines are, of course,

heavy, so they are not a good choice for airplanes.  

	The "real ones" have been developed to produce the most power at

the least weight, retaining the highest reliability possible.   System

simplicity is one of the ways that this is achieved.

	Now, we Kitfox pilots are flying airplanes that are in the class

called "experimental", so this opens the door for trying different

things, which is the decision that you are of course struggling with.

I would try to make the choice depending on where my flights are likely

to be carried out,  just how much night flight you anticipate, and how

much you will 'enjoy' the systems complication associated with the

Subbie.   

	Also try to remember how the different engines and especially

their major components look to you comparatively whenever you have seen

them displayed at shows.  Here is where I rest my case for the "real

ones", but if your anticipated flight profiles give you the opportunity

to experiment with your power unit, then use the car engine, and join

the ranks of those who are in a continuous mode of solving carburetor

problems, cooling leaks, gearbox issues, and head gasket concerns,

ignition system questions, oil leaks, not to mention the stress factors

that arise due to the loads that are passed through an engine that was

designed to be connected to a bell housing/transmission, and not to have

the gyro loads of a propeller induced into its 'block' and then taken on

through to a mounting system that was not the one considered by its

designer.   Your type 5 is well able to do mild aerobatics, so if you

anticipate doing any of these, then you would want to be sure your power

unit will not get sick before you do.  

	Yes, I know, some of the most famous military craft have liquid

cooling, and a geared propeller.  They also were designed from the

ground up as aircraft, and military ones at that, so I contend that they

make a poor comparison or justification for those systems in a civilian

light plane.    

	Whichever you choose, do install the "help me Joe" kit offered

by John McBean, this will do wonders to refine the control system, and

keep the back pressure needed under control on approaches, since you

will have an airplane that  tends to be nose heavy, and the elevator has

no aero-counter force designed in.   This spring coupling is designed

for the model 5's thru 7's, and in my opinion is an essential

improvement when heavier engines are used.  



Duane Rueb, N24ZM



--

Fox5flyer
Guest

Posted: Wed Dec 06, 2006 10:52 am Post subject: 0-235 vs Turbo Subaru

Good narrative Duane.  Even though I'm a Soob driver I agree with all of it.

However, if it weren't for us experimenters, even the Lycosaurs' and Conts

wouldn't be around today.  

It sounds as if you must have installed the spring coupler in 24ZM.  Can you

be more specific on how it works, what is included with the kit, and what it

costs?

Thanks,

Deke



 	  Quote: 	
		  

 Jim:



 Direct drive and a single cooling system, maintainability

 'anywhere' would favor the Lycoming.  Assuming that both engines are in

 good serviceable condition, I know which one I would rather be flying

 behind when, say approximately 100 miles west of Denver at 13,500 ft.

 (for a brief period).  I would definitely vote for the Lycoming at that

 time.

 The "real ones" are often criticized for being behind the times,

 but the truth is that they are tried and true, and have the advantage of

 being designed from the ground up as aircraft engines, and have

 benefited from years of improvement, and advances of material science.

 Since aircraft engines experience a very different operational profile

 than car engines, putting out 100% power at every takeoff, and then

 65-75% continuously thereafter, until descent and landing, all of their

 parts were designed with that operation profile in mind, from the

 crankshaft to the valves.  They are often compared to tractor engines,

 and with good reason, since a tractor also needs to put out a high

 percentage of its power continuously.  Tractor engines are, of course,

 heavy, so they are not a good choice for airplanes.

 The "real ones" have been developed to produce the most power at

 the least weight, retaining the highest reliability possible.   System

 simplicity is one of the ways that this is achieved.

 Now, we Kitfox pilots are flying airplanes that are in the class

 called "experimental", so this opens the door for trying different

 things, which is the decision that you are of course struggling with.

 I would try to make the choice depending on where my flights are likely

 to be carried out,  just how much night flight you anticipate, and how

 much you will 'enjoy' the systems complication associated with the

 Subbie.

 Also try to remember how the different engines and especially

 their major components look to you comparatively whenever you have seen

 them displayed at shows.  Here is where I rest my case for the "real

 ones", but if your anticipated flight profiles give you the opportunity

 to experiment with your power unit, then use the car engine, and join

 the ranks of those who are in a continuous mode of solving carburetor

 problems, cooling leaks, gearbox issues, and head gasket concerns,

 ignition system questions, oil leaks, not to mention the stress factors

 that arise due to the loads that are passed through an engine that was

 designed to be connected to a bell housing/transmission, and not to have

 the gyro loads of a propeller induced into its 'block' and then taken on

 through to a mounting system that was not the one considered by its

 designer.   Your type 5 is well able to do mild aerobatics, so if you

 anticipate doing any of these, then you would want to be sure your power

 unit will not get sick before you do.

 Yes, I know, some of the most famous military craft have liquid

 cooling, and a geared propeller.  They also were designed from the

 ground up as aircraft, and military ones at that, so I contend that they

 make a poor comparison or justification for those systems in a civilian

 light plane.

 Whichever you choose, do install the "help me Joe" kit offered

 by John McBean, this will do wonders to refine the control system, and

 keep the back pressure needed under control on approaches, since you

 will have an airplane that  tends to be nose heavy, and the elevator has

 no aero-counter force designed in.   This spring coupling is designed

 for the model 5's thru 7's, and in my opinion is an essential

 improvement when heavier engines are used.



 Duane Rueb, N24ZM

ruebd(at)skymail.csus.edu
Guest

Posted: Wed Dec 06, 2006 11:50 am Post subject: 0-235 vs Turbo Subaru

Deke, and list:



	Yes, I did install the "help me Joe" kit into N24ZM.  It was

priced at $85 when I purchased it, and it couples the elevator to the

flaps, and installs behind the seat.  	The only thing that might

improve the kit would be a suggestion as to how to stretch the fairly

stiff (for human strength, and the position available if working through

the seat access panels that are in my plane) spring.  

	What I did with Milts help was to first put the spring in a

bench vice and stretch it just enough to insert a (approx 3/4") nylon

strap between some coils near the end that we would be pulling from,

then with two people working, with one pulling the straps, and the other

guiding the sprint to the front hook point.  	

	If the airplane has no access panels in the seat back, you will

have to remove the seat, which will make attaching the spring easier, so

you may not feel you need to use a strap, but it worked so well, that it

may still be the best approach.  

	Take note of the elevator droop you have before you install this

kit, and after, and you will see quite a difference.  The elevator no

longer droops, and will stay level.  The real change is when the flaps

are put in as on an approach, where the spring now helps you with the

extra back pressure/trim now needed.  On mine, the trim can now

compensate for this, allowing neutral or very near neutral stick back

pressure with one notch of flap at an approach speed of 60-65mph

indicated.  With full flap, some additional back pressure is needed, but

much less than before.  

	I think that this kit results in a better control system feel

all around, too, not just on approaches.  



Duane



--

Glenn Horne

Joined: 10 Jan 2006
Posts: 96

Posted: Wed Dec 06, 2006 11:57 am Post subject: 0-235 vs Turbo Subaru

You are right. Each to their own.

For me there are only two. Lyc. & Cont.

GG

---

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Wed Dec 06, 2006 12:04 pm Post subject: 0-235 vs Turbo Subaru

Don't forget the franklins........

and yes Rotax a dominant player.



I would take a 912 over a soob anyday for a floatplane especially.

Dave

---

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jcorner(at)shaw.ca
Guest

Posted: Thu Dec 07, 2006 6:57 pm Post subject: 0-235 vs Turbo Subaru

Thanks to all that responded to my question.  Since this is a very  

personnel decision I was not surprised that most replies were

off-list.  Most people are not willing to get involved in a potential  

long debate and I certainly respect that.



  The result of it all is that I have decided to go with the  

Lycosaurus..... ten years ago, approaching 60 rather than 70 my  

decision I think would have been the other way.  All those extra  

horses sure look tempting!



Thanks again.



Jim

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