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Jabiru 3300 vs. Corvair in a 601XL

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craig(at)craigandjean.com
Guest

Posted: Mon Jul 31, 2006 8:05 pm Post subject: Jabiru 3300 vs. Corvair in a 601XL

There is no need to speculate about the relative in-the-air performance 

of these two engines. Phil Maxson's 601XL/Corvair is flying and I 

believe he has published some performance numbers. Anyone flying behind 

a 3300 can publish their numbers and we can compare. The atmospheric 

conditions won't be identical but they should be close enough for a 

useful comparison to be made.



-- Craig

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pmaxpmax(at)HOTMAIL.COM
Guest

Posted: Tue Aug 01, 2006 6:00 am Post subject: Jabiru 3300 vs. Corvair in a 601XL

Yes, my performance numbers are published in the archives.  For reference, 

I'll reiterate:



Corvair, 164 cubic inch, front start, WW conversion, Elison EFS-3A Carb

Warp Drive Prop, Set to 8.5 degrees

Empty Weight: 777 pounds

Gross Weight: 1320 pounds



Cruise Speed: 125 mph, 3100 rpm, Std atmospheric conditions, gross weight

Fuel Burn: 5.5 gph

Other factors: nose wheel, no wheel pants, no brake line fairings, no 

fairing on the steps

Climb: 1200 fpm



This is the first set-up I've tried.  I want to put on wheel pants and 

fairings this winter, as well as change the prop pitch a little.  The climb 

performance is overwhelming, but I believe it is robbing me of top end 

performance.  I am also interested in using an Sensenich wood prop, but I 

don't know when that will happen.



Paul,



In order to do a true test you would have to have two similarly equiped 

planes under the same conditions.  (I thought that was understood, but 

perhaps not).  So, in the absence of doing a full series of tests, like EAA 

publishes frequently, most people accept "bench" tests, like dynamometer 

tests to compare horsepower.  It is much easier to keep test conditions the 

same.  If you are unwilling to do the testing yourself (which I would LOVE 

to see) you can review William Wynne's comparison to the O-200 on his dyno.  

It's is on flycorvair.com.

Phil Maxson

601XL/Corvair

Northwest New Jersey

 	  Quote: 	
		  From: craig(at)craigandjean.com

Subject: Jabiru 3300 vs. Corvair in a 601XL






There is no need to speculate about the relative in-the-air performance of 

these two engines. Phil Maxson's 601XL/Corvair is flying and I believe he 

has published some performance numbers. Anyone flying behind a 3300 can 

publish their numbers and we can compare. The atmospheric conditions won't 

be identical but they should be close enough for a useful comparison to be 

made.



-- Craig

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p.mulwitz(at)worldnet.att
Guest

Posted: Tue Aug 01, 2006 7:03 am Post subject: Jabiru 3300 vs. Corvair in a 601XL

Hi Phil,

Thanks for publishing your numbers.

I couldn't tell if you did your flight testing at gross weight.  Is 

this the case, or was this testing done with no passenger?

Your climb numbers are better than the ones published for the 

Lycoming engine on ZAC's web site, but your cruise speed is somewhat 

slower.  I presume the numbers on ZAC's site are results of testing 

at full gross weight, but I can't be sure that is the case.

It is not surprising that the conversion engine you have might not 

perform as well as the Lycoming engine.  You quoted your displacement 

at 164 cu. in. while the Lycoming displacement is 235 cu. in.   This 

difference alone is enough to suspect the Lycoming engine might 

produce more power.

I am sorry I don't agree with you about bench testing engines being a 

valid way to measure their performance.  It seems possible to me that 

an engine that is poorly integrated in an airplane (as might be at 

risk when putting an automobile engine in an airplane) would not 

translate bench performance to flight performance.  I suspect the 

bench testing and particularly the dynamometer testing are designed 

to test engines for application in automobiles.  Even if the bench 

testing were completely valid and appropriate, the issues of engine 

weight, installation location with regard to aircraft CG, propeller 

choice, and of course aircraft rigging all play into the final 

aircraft performance.  I agree the bench testing is appropriate to 

determine the success of the conversion process, but it is only the 

flight performance of the final product that seems appropriate to me 

for the purpose of selecting a power plant for a plane.

I agree with you about needing similarly equipped planes for a truly 

valid comparison.  Rather than one plane with each engine 

installation, I would prefer many planes.  That way the variations in 

each plane could be averaged out.

Best regards,

Paul

XL fuselage

do not archive

At 06:59 AM 8/1/2006, you wrote:

 	  Quote: 	

Yes, my performance numbers are published in the archives.  For 

reference, I'll reiterate:

Corvair, 164 cubic inch, front start, WW conversion, Elison EFS-3A Carb

Warp Drive Prop, Set to 8.5 degrees

Empty Weight: 777 pounds

Gross Weight: 1320 pounds

Cruise Speed: 125 mph, 3100 rpm, Std atmospheric conditions, gross weight

Fuel Burn: 5.5 gph

Other factors: nose wheel, no wheel pants, no brake line fairings, 

no fairing on the steps

Climb: 1200 fpm

This is the first set-up I've tried.  I want to put on wheel pants 

and fairings this winter, as well as change the prop pitch a 

little.  The climb performance is overwhelming, but I believe it is 

robbing me of top end performance.  I am also interested in using an 

Sensenich wood prop, but I don't know when that will happen.

Paul,

In order to do a true test you would have to have two similarly 

equiped planes under the same conditions.  (I thought that was 

understood, but perhaps not).  So, in the absence of doing a full 

series of tests, like EAA publishes frequently, most people accept 

"bench" tests, like dynamometer tests to compare horsepower.  It is 

much easier to keep test conditions the same.  If you are unwilling 

to do the testing yourself (which I would LOVE to see) you can 

review William Wynne's comparison to the O-200 on his dyno.

It's is on flycorvair.com.

Phil Maxson

601XL/Corvair

Northwest New Jersey

>From: craig(at)craigandjean.com

>Subject: Jabiru 3300 vs. Corvair in a 601XL

>

>

>

>There is no need to speculate about the relative in-the-air 

>performance of these two engines. Phil Maxson's 601XL/Corvair is 

>flying and I believe he has published some performance numbers. 

>Anyone flying behind a 3300 can publish their numbers and we can 

>compare. The atmospheric conditions won't be identical but they 

>should be close enough for a useful comparison to be made.

>

>-- Craig

---------------------------------------------

Paul Mulwitz

32013 NE Dial Road

Camas, WA 98607

---------------------------------------------

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admin(at)arachnidrobotics
Guest

Posted: Tue Aug 01, 2006 7:34 am Post subject: Jabiru 3300 vs. Corvair in a 601XL

Paul, I'm afraid you may be disappointed if you're expecting to get 

a cruise speed much higher than 125 mph from a Lycoming.  Especially 

without wheel pants or fairings.  Chris designs great little airplanes, 

but his numbers are a bit skewed.  All of them, in almost every area, 

are definitely on the optimistic side (time to build, cruise speed, Load 

Factor).

    Take some time and check out a few of the builders' web sites for 

their numbers.  You'll find a few that hit the published numbers, but 

only after a fair amount of clean up and fairing. 



    Tom Henderson

    601XL Fuselage in process

Do Not Archive



Paul Mulwitz wrote:



 	  Quote: 	
		   

 <p.mulwitz(at)worldnet.att.net>



 Hi Phil,



 Thanks for publishing your numbers.



 I couldn't tell if you did your flight testing at gross weight.  Is 

 this the case, or was this testing done with no passenger?



 Your climb numbers are better than the ones published for the Lycoming 

 engine on ZAC's web site, but your cruise speed is somewhat slower.  I 

 presume the numbers on ZAC's site are results of testing at full gross 

 weight, but I can't be sure that is the case.



 It is not surprising that the conversion engine you have might not 

 perform as well as the Lycoming engine.  You quoted your displacement 

 at 164 cu. in. while the Lycoming displacement is 235 cu. in.   This 

 difference alone is enough to suspect the Lycoming engine might 

 produce more power.



 I am sorry I don't agree with you about bench testing engines being a 

 valid way to measure their performance.  It seems possible to me that 

 an engine that is poorly integrated in an airplane (as might be at 

 risk when putting an automobile engine in an airplane) would not 

 translate bench performance to flight performance.  I suspect the 

 bench testing and particularly the dynamometer testing are designed to 

 test engines for application in automobiles.  Even if the bench 

 testing were completely valid and appropriate, the issues of engine 

 weight, installation location with regard to aircraft CG, propeller 

 choice, and of course aircraft rigging all play into the final 

 aircraft performance.  I agree the bench testing is appropriate to 

 determine the success of the conversion process, but it is only the 

 flight performance of the final product that seems appropriate to me 

 for the purpose of selecting a power plant for a plane.



 I agree with you about needing similarly equipped planes for a truly 

 valid comparison.  Rather than one plane with each engine 

 installation, I would prefer many planes.  That way the variations in 

 each plane could be averaged out.



 Best regards,



 Paul

 XL fuselage

 do not archive

 At 06:59 AM 8/1/2006, you wrote:



> 

>

> Yes, my performance numbers are published in the archives.  For 

> reference, I'll reiterate:

>

> Corvair, 164 cubic inch, front start, WW conversion, Elison EFS-3A Carb

> Warp Drive Prop, Set to 8.5 degrees

> Empty Weight: 777 pounds

> Gross Weight: 1320 pounds

>

> Cruise Speed: 125 mph, 3100 rpm, Std atmospheric conditions, gross 

> weight

> Fuel Burn: 5.5 gph

> Other factors: nose wheel, no wheel pants, no brake line fairings, no 

> fairing on the steps

> Climb: 1200 fpm

>

> This is the first set-up I've tried.  I want to put on wheel pants 

> and fairings this winter, as well as change the prop pitch a little.  

> The climb performance is overwhelming, but I believe it is robbing me 

> of top end performance.  I am also interested in using an Sensenich 

> wood prop, but I don't know when that will happen.

>

> Paul,

>

> In order to do a true test you would have to have two similarly 

> equiped planes under the same conditions.  (I thought that was 

> understood, but perhaps not).  So, in the absence of doing a full 

> series of tests, like EAA publishes frequently, most people accept 

> "bench" tests, like dynamometer tests to compare horsepower.  It is 

> much easier to keep test conditions the same.  If you are unwilling 

> to do the testing yourself (which I would LOVE to see) you can review 

> William Wynne's comparison to the O-200 on his dyno.

> It's is on flycorvair.com.

> Phil Maxson

> 601XL/Corvair

> Northwest New Jersey

>> From: craig(at)craigandjean.com

>> Subject: Jabiru 3300 vs. Corvair in a 601XL

>>

>> 

>>

>> There is no need to speculate about the relative in-the-air 

>> performance of these two engines. Phil Maxson's 601XL/Corvair is 

>> flying and I believe he has published some performance numbers. 

>> Anyone flying behind a 3300 can publish their numbers and we can 

>> compare. The atmospheric conditions won't be identical but they 

>> should be close enough for a useful comparison to be made.

>>

>> -- Craig

>

>



 ---------------------------------------------

 Paul Mulwitz

 32013 NE Dial Road

 Camas, WA 98607

 ---------------------------------------------





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Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Tue Aug 01, 2006 10:50 am Post subject: Re: Jabiru 3300 vs. Corvair in a 601XL

I've only found one spot in the flycorvair.com site that quotes a speed on WW's 601XL. Here's the quote:



 	  Quote: 	
		  Straight and level, the plane did 130mph at 23" MAP and 2700rpm. This is a low cruise power setting. Keep in mind, the plane has 6x6 tires, no gear leg fairings, no wheel pants, etc.

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_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

craig(at)craigandjean.com
Guest

Posted: Tue Aug 01, 2006 7:20 pm Post subject: Jabiru 3300 vs. Corvair in a 601XL

It is also a tail-dragger.



-- Craig 



--

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