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occom

Joined: 26 Aug 2006
Posts: 404

Posted: Wed Jan 09, 2008 3:19 pm Post subject: LOW power limits

I know the bulk of the list feels power is good and  more of it is better, but I'm curious how much is actually NEEDED. My 582 will  perform fine, great even with 65 HP. I know from others that a VW will perform  well and that an HKS 700E will be roughly the same in most respects as my Rotax.  There are people out there flying on a 503 although I have no figures as to  performance. 

  

 An Aeronca C3 made do with 35 HP and a lousy prop  choice. So, I'm curious with it's big wing, efficient airfoil and light  weight, how few ponies could a kitfox flier make do with? We don't have  climb at 1500 FPM, 30% of that will do with the runways many of of us use.   Some of the early Cubs only had 40 HP. 

  

 So, how low (HP) can we go? 

  

 Dave Goddard- Mod IV 1050/582

do not  archive

  [quote][b]

runwayrex(at)juno.com
Guest

Posted: Wed Jan 09, 2008 4:01 pm Post subject: LOW power limits

Interesting question Dave. I tend to think with you on this subject. I have a Model 3 right now and enjoy being able to use unleaded regular gas with my 80 horse 912 UL (warp drive). I am very happy with the performance of the plane and cruise between 100 and 105 mph (GPS).  

My next plane will be a Model 7 and I'm wondering if I can still get away with those  80 horses and regular fuel. My current plane weighs 660 pounds and I expect that a Model seven will be about 100 pounds more. I'm wondering if an in-flight adjustable prop would make up for those extra 100 pounds. Is anybody running a Model 7 with the 912 UL? 

Rex Phelps 1050

-- "Dave G." <occom(at)ns.sympatico.ca> wrote:

 I know the bulk of the list feels power is good and more of it is better, but I'm curious how much is actually NEEDED. My 582 will perform fine, great even with 65 HP. I know from others that a VW will perform well and that an HKS 700E will be roughly the same in most respects as my Rotax. There are people out there flying on a 503 although I have no figures as to performance. 

  

 An Aeronca C3 made do with 35 HP and a lousy prop choice. So, I'm curious with it's big wing, efficient airfoil and light weight, how few ponies could a kitfox flier make do with? We don't have climb at 1500 FPM, 30% of that will do with the runways many of of us use.  Some of the early Cubs only had 40 HP. 

  

 So, how low (HP) can we go? 

  

 Dave Goddard- Mod IV 1050/582

do not archive

 	  Quote: 	
		  



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   [quote][b]

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Wed Jan 09, 2008 6:56 pm Post subject: Re: LOW power limits

 	  Quote: 	
		  I know the bulk of the list feels power is good and more of it is better, but I'm curious how much is actually NEEDED. My 582 will perform fine, great even with 65 HP. I know from others that a VW will perform well and that an HKS 700E will be roughly the same in most respects as my Rotax. There are people out there flying on a 503 although I have no figures as to performance. 



An Aeronca C3 made do with 35 HP and a lousy prop choice. So, I'm curious with it's big wing, efficient airfoil and light weight, how few ponies could a kitfox flier make do with? We don't have climb at 1500 FPM, 30% of that will do with the runways many of of us use. Some of the early Cubs only had 40 HP. 	




Dave, First off a rotax 582 is rated at 64 HP with a stock pipe. Kitfox pipe it not stock OEM - it is modified and has resulted in about a 5 hp loss so you will be at about 60 hp for round numbers. If you search back i did some testing on this and modified the exhaust to find out for sure .

My you tube videos document some of this   http://www.youtube.com/profile?user=kitfoxflyer



The HKS maybe close to 582 but not faster. 

VW direct drive no hope  in faster than a 582 for take off ,but might be in cruise if all set up right .  VW need a reduction drive to optimize it  better. 



If you got a 582 I would stick with that. Mine has 380 hours on it since last June 2006 and my thrid engine in this Kitfox.  When will it stop> ?  Everyone says they not dependable.



You last question -- well you could fly on likely a 25 HP engine and that would depend on your Kitfox weight.  If you look at John Knapps Avid here http://www.youtube.com/watch?v=qjDSatUSoCY  it gets off REAL QUICK,  I think a 583   90 HP and a 380  lb plane on floats does it .  I would guess your Kitfox Iv will be 500 to 550 lbs as it simular to mine ?

_________________
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occom

Joined: 26 Aug 2006
Posts: 404

Posted: Thu Jan 10, 2008 3:57 am Post subject: LOW power limits

Hi Dave, my empty weight was 551 and I expect it will change a few lbs when 

my recover is complete. I knew from reading your experiments around the 582 

that I as down a little from rated. I'm not really after improving my Kitfox 

in any way. I'll learn to fly it and then assess whether I want to change 

something. My basis for asking the question was that most of the engine 

questions center around how to obtain more power and speed, up to the point 

where some have asked about some really heavy engine combinations. It simply 

made me wonder how few ponies could we aviate on? 40, 35, 30?



Dave Goddard- Mod IV 1050/582

do not archive

---

Tom Jones

Joined: 12 Mar 2006
Posts: 752
Location: Ellensburg, WA

Posted: Thu Jan 10, 2008 7:25 am Post subject: Re: LOW power limits

 	  Quote: 	
		  I'm curious with it's big wing, efficient airfoil and light weight, how few ponies could a kitfox flier make do with? We don't have climb at 1500 FPM, 30% of that will do with the runways many of of us use. Some of the early Cubs only had 40 HP. 	




Dave, I am nearing the completion of phase one flight testing my Classic 4 with a 52 hp 503 Rotax.  Prop is a 72" Warp two blade, gear box is 3:1, prop pitch set for 6200 RPM at 60 mph climb.  Fairing on tube gear, no fairing on lift struts.  The Classic 4 is limited to 1050 max gross weight with a 503.  This is a power limitation, not an airframe limitation.  Here's some raw performance numbers.



Gross wt 760, density altitude 1500 ft, climb 730 fpm.

Gross wt 890, density altitude 1000 ft, climb 525 fpm.

Gross wt 954, density altitude 1500 ft, climb 480 fpm.

Gross wt 1050, density altitude 1800ft, climb 420 fpm.



Stall speed at 760 gross clean = 38 mph, 20 degrees flaps = 36 mph.

Stall speed at 1050 gross clean = 46 mph, 20 degrees flaps = 42 mph.



True air speed at 5800 rpm is 78 mph. 



Best rate of climb speed = 58 mph, best angle =55, not much dif.



If I made my graph correctly, service ceiling at 760 gross is about 12,600 ft. and rate of climb at sea level at 760 gross is 810 fpm.



I havent measured the take off run but can say it is very short at 760 gross and increases to probably about twice the distance at 1050 gross. 



These performance numbers are very close to what the old Skystar advertised.  Their hook for selling this engine with the classic 4 was "Fun affordable flying around the patch now and upgrade to more power at a later date when you can afford it".

_________________
Tom Jones
Classic IV
503 Rotax, 72 inch Two blade Warp
Ellensburg, WA

occom

Joined: 26 Aug 2006
Posts: 404

Posted: Thu Jan 10, 2008 2:19 pm Post subject: LOW power limits

Thanks Tom, good performance numbers for a small engine and I'd guess 

there's room left at the bottom of the chart yet! I wonder what a 447 would 

do?



Dave Goddard- Mod IV 1050/582

do not archive

---

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Thu Jan 10, 2008 2:28 pm Post subject: Re: LOW power limits

I would think over all the 582 is the best fit for performance especially when you are flying dual or on floats.  



Dependability ?   about the same 503 or 582 . 



Tom is cruising at 78 mph whereas mine with  Kingfox tires about 92 mph at 5800 to 6000 rpm .  With golf cart tires eg 16.5 x 8.00   ad 2 mph. 

Dave are your wings covered yet?  If not I might be able to help  you pick up a few more mph  before covering.

Sbennett3(at)aol.com
Guest

Posted: Thu Jan 10, 2008 3:43 pm Post subject: LOW power limits

I wanted long distance between tbo, and less fuel burn. My  perfect engine combo is the 912.  Oh ya, reliability ...   My  plane weighs 607lbs.  Steve B  4-912



Start the year off right.  Easy ways to stay in shape in the new year.

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Thu Jan 10, 2008 9:23 pm Post subject: Re: LOW power limits

 	  Quote: 	
		  I wanted long distance between tbo, and less fuel burn. My perfect engine combo is the 912. Oh ya, reliability ... My plane weighs 607lbs. Steve B 4-912 

	




no arguement there Steve.   912 a great choice as is a 912s or  914. 



600 lbs IV with a 912 would be a good performer. 

I think Dave already has a 582 though.  Would be happy to sell him a new 912 though.

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Fri Jan 11, 2008 9:15 am Post subject: LOW power limits

This is a situation where figures really count.  I have few, very few.



A couple of years ago when I first got my 'Fox I had a lot of trouble

gaining any altitude.  H.. I had trouble getting into the air.  A half mile

or so of water in calmish conditions was normal.  My father's old C172 on

floats with the old Franklin wood burner started to look good.  A calm day

and over an hour was able to garner me 3000'(at) 6000rpm.  Talk about

disappointment!



The plane was being flown on Aerocet floats at close to gross weight (850 lb

T.O.).  My problem as it turned out was a faulty tachometer.  Go figure.  My

Westach was reading 20% too high so my actual rpm was close to 4800.  I was

able to keep the heavy bird in the air at 2000' with 5800rpm indicated (4650

actual).

Using the table found at:

http://www.ultralightnews.ca/rotax582/pdfiles/582enginedatasheet.pdf  I am

using the shortened Kitfox expansion chamber so I interpolate my Hp to be

around 38hp - 5% = 36hp at 5800  (on the faulty tach.  Getting to 1500'asl

was no problem but after that it was pure agony.



Now I have replaced my tach with a solid state Microtach, aircraft

performance has rocketed.  A gentle pull up at 1500' will now result in a

sustained climb in excess of 600'/min and an initial rate that will pin the

vsi. So far I've only gone as far a 3000'asl.  Take off at close to calm

conditions and gross weight are around 600' if that long.  With minimal fuel

I bet I would be off in less than 300'.



Of course in my neck of the woods 3000'asl is mostly 3000'agl  



Noel



--

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

clint_bazzill(at)hotmail.
Guest

Posted: Fri Jan 11, 2008 11:05 am Post subject: LOW power limits

A new 912 has a TBO of 1500 hours.  Thats the TBO but in reality its 2000 hours.  How much more would you like?   Clint [quote]  From: Sbennett3(at)aol.com

Date: Thu, 10 Jan 2008 18:43:14 -0500

Subject: Re: Re: LOW power limits

To: kitfox-list(at)matronics.com

  I wanted long distance between tbo, and less fuel burn. My perfect engine combo is the 912.  Oh ya, reliability ...   My plane weighs 607lbs.  Steve B  4-912

   Start the year off right. Easy ways to stay in shape in the new year. 

 	  Quote: 	

arget=_blank>http://www.matronics.com/Navigator?Kitfox-List

p://forums.matronics.com

blank>http://www.matronics.com/contribution

[b]

Michel

Joined: 10 Jan 2006
Posts: 966
Location: Norway

Posted: Fri Jan 11, 2008 11:30 am Post subject: LOW power limits

On Jan 11, 2008, at 8:04 PM, Clint Bazzill wrote:

 	  Quote: 	
		   A new 912 has a TBO of 1500 hours.  Thats the TBO but in reality its 

 2000 hours.


	


Clint, I was told that my Jabiru 2200 had a TBO of 2,000 hours, which 

was twice that of the 912, because the Jabiru has a max RPM of 3,000 - 

half that of the Rotax. It made sense to me at the time. Have I been 

fooled by my Jabiru dealer?

Just wondering; I know so little about engines.



Cheers,

Michel Verheughe

Norway

Kitfox 3 - Jabiru 2200

_________________
Kitfox 3 - Jabiru 2200

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Fri Jan 11, 2008 11:53 am Post subject: LOW power limits

What I question about the Jab is the 3300 rpm...  That requires a very short

prop to keep the inertial stresses down.  That means that full power for

takeoff isn't either developed or efficient.  What i like about it is of

course the fact you can leave the redrive at the shop 

Noel Loveys

AME Intern, RPP

Kitfox III-A, 582,B box

Ivo IFA, Aerocet 1100 floats





--

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

rzeppin(at)cox.net
Guest

Posted: Fri Jan 11, 2008 3:51 pm Post subject: LOW power limits

Anyone know what the average cost of an overhaul is on a 912?

Just trying to get a real idea on the cost of owning...



Ron



Clint Bazzill wrote:

 	  Quote: 	
		  

 A new 912 has a TBO of 1500 hours.  Thats the TBO but in reality its 

 2000 hours.  How much more would you like?   Clint



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

     From: Sbennett3(at)aol.com

     Date: Thu, 10 Jan 2008 18:43:14 -0500

     Subject: Re: Re: LOW power limits

     To: kitfox-list(at)matronics.com



     I wanted long distance between tbo, and less fuel burn. My perfect

     engine combo is the 912.  Oh ya, reliability ...   My plane weighs

     607lbs.  Steve B  4-912



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

     Start the year off right. Easy ways to stay in shape

     <http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489>

     in the new year.



     *



     arget=_blank>http://www.matronics.com/Navigator?Kitfox-List

     p://forums.matronics.com

     blank>http://www.matronics.com/contribution



     *



 *

 *

clint_bazzill(at)hotmail.
Guest

Posted: Fri Jan 11, 2008 3:51 pm Post subject: LOW power limits

Michael,

 I think the Jabiru is a nice engine.  Am going to write a nice long article about these different engines.  My friend had (had) a very nice Avid MK4 that he had a Rotax 618.  Almost had one myself and he had several engine failures.  He decided to put in a different 4 stroke engine.  I tried to talk him into a 912 but he insisted on the Jabiru.  I have flown with him for about 8 hours in his plane, he liked it as it kept running.  He sold it a few months ago and I am 100% sure if he had installed the 912UL he would still have it.  The performance would have been so much better that he couldn't part with it.  More on that later.  Clint

 	  Quote: 	
		   From: michel(at)online.no

 Subject: Re: Re: LOW power limits

 Date: Fri, 11 Jan 2008 20:29:23 +0100

 To: kitfox-list(at)matronics.com

 --> Kitfox-List message posted by: Michel Verheughe <michel(at)online.no>

 On Jan 11, 2008, at 8:04 PM, Clint Bazzill wrote:

 > A new 912 has a TBO of 1500 hours.  Thats the TBO but in reality its 

 > 2000 hours.

 Clint, I was told that my Jabiru 2200 had a TBO of 2,000 hours, which 

 was twice that of the 912, because the Jabiru has a max RPM of 3,000 - 

 half that of the Rotax. It made sense to me at the time. Have I been 

 fooled by my Jabiru dealer?

 Just wondering; I know so little about engines.

 Cheers,

 Michel Verheughe

 Norway

 Kitfox 3 - Jabiru 2=======================

&g==

 	  Quote: 	

  [quote][b]

Sbennett3(at)aol.com
Guest

Posted: Fri Jan 11, 2008 5:04 pm Post subject: LOW power limits

I have 803hrs. ttaf and it still runs like a  champ...  Steve B  4-912



Start the year off right.  Easy ways to stay in shape in the new year. 

  [quote][b]

jcrowder(at)lpbroadband.n
Guest

Posted: Fri Jan 11, 2008 6:13 pm Post subject: LOW power limits

Which Jabiru  engine did he have?  How well was it set up and did he have 100 hours  one it.  Many Jab owners say their engine continues to perform better  up through the first 100 hours.  To get their performance Rotax owners  often resort to more expensive and complex adjustable props.  What is  the difference in the part count?  And of course performance will be better  with a Jabiru 3300, 120 hp engine, than with a Jabiru 2200, 80  hp engine.  Older and newer Jabiru models also have different  carburetor jetting among other engine changes.  It will be a while  before we really know how these engines match up and maintain.  All of us  have an interest in the engines we invest in.   I submit to  you that it is rare to have someone not advocate the engine they know and  own.  Likewise our research tends to lead to the outcome we expect.   

  

 In the end we  are fortunate to have more good engine choice than ever  before.

  

 Jim  Crowder

  

  

 [quote]   --

clint_bazzill(at)hotmail.
Guest

Posted: Sat Jan 12, 2008 11:10 am Post subject: LOW power limits

Hi had the Jabiru 2200.  Had lots of problems with noise, engine and electrical from spark plugs etc.  I did not like the noise and was hard to hear on intercom.  The guy who bought it put on a different prop hoping for better performance but sent it back.  You can only go so far with a VW type direct drive engine with props.  I had a 912UL and was happy with it.  It was in a Model IV and performed great.  The guys at the airport asked why I would want anything else.  When my friend flys with me he comments how quiet the aircraft is.  With 2 of us in his Avid it would climb almost as good as a 150 with 2 people. 

  

 Clint

 [quote]  From: jcrowder(at)lpbroadband.net

To: kitfox-list(at)matronics.com

Subject: RE: Re: LOW power limits

Date: Fri, 11 Jan 2008 19:11:45 -0700



   .ExternalClass .EC_hmmessage P {padding-right:0px;padding-left:0px;padding-bottom:0px;padding-top:0px;} .ExternalClass EC_BODY.hmmessage {font-size:10pt;font-family:Tahoma;}   Which Jabiru engine did he have?  How well was it set up and did he have 100 hours one it.  Many Jab owners say their engine continues to perform better up through the first 100 hours.  To get their performance Rotax owners often resort to more expensive and complex adjustable props.  What is the difference in the part count?  And of course performance will be better with a Jabiru 3300, 120 hp engine, than with a Jabiru 2200, 80 hp engine.  Older and newer Jabiru models also have different carburetor jetting among other engine changes.  It will be a while before we really know how these engines match up and maintain.  All of us have an interest in the engines we invest in.   I submit to you that it is rare to have someone not advocate the engine they know and own.  Likewise our research tends to lead to the outcome we expect.  

  

 In the end we are fortunate to have more good engine choice than ever before.

  

 Jim Crowder

  

  

 [quote] --

av8rps

Joined: 05 Jan 2008
Posts: 33
Location: Central Wisconsin

Posted: Sat Jan 12, 2008 3:49 pm Post subject: Re: LOW power limits

(Dave Goddard said; I know the bulk of the list feels power is good and  more of it is better, but I'm curious how much is actually NEEDED...)



Dave,



I put a bunch of hours on the Avid Flyer prototype N99AF, which was powered by a 43 hp Cuyuna engine (which I think was more like 40 hp).  Compared to the 65 hp J-3 Cub and the spam cans I trained in, it was a little rocketship, climbing solo at 1400 fpm, using 75 feet for takeoff, and cruising around 80 mph on around 3 gph.  But that airplane was only 364 lbs empty.  So weight is everything when one talks about how much horsepower is required. But even on floats (empty weight now at approx 500 lbs) and two people it still flew very well.  In fact, it was a great performing floatplane, outperforming most other floatplanes unless they had engines 3 or 4 times larger.  And fwiw, I flew that little Avid to 10,000 ft msl regularly on hot summer days to cool off, shut the engine off and glide around just to seen how long of a glide I could get (seriously).   It had a wonderful service ceiling, blowing most other planes away that I had ever flown. (See attached picture)  



I also knew of an Avid that flew with a 447 rotax for years. Flew just great.  So I'm sure a light Kitfox would do ok as well.



Paul Seehafer

Dead stick in N99AF - 1.JPG

Description:

Filesize:

629.96 KB

Viewed:

473 Time(s)

_________________
Model IV-1200 912ul Amphib
Avid Flyer Sn#1 and Sn#26
Highlander 912s taildragger
Lake Amphibian
Central Wisconsin
paul676@tds.net

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Sat Jan 12, 2008 3:50 pm Post subject: LOW power limits

160 hp on the nose of a Super Cub will climb faster than my ‘Fox with the 582.  It also takes a lot more room to get the floats out of the water.  The $1.50 is hardly worth talking about because it will hardly lift the floats out of the water let alone out climb anything.  The $1.50 is faster in the cruise though, on wheels.  

   

Hmmm. Wonder why I’m not a fan of the C150????  

   

Noel  

       

From: owner-kitfox-list-server(at)matronics.com [mailto:owner-kitfox-list-server(at)matronics.com] On Behalf Of Clint Bazzill

 Sent: Saturday, January 12, 2008 3:35 PM

 To: kitfox-list(at)matronics.com

 Subject: RE: Re: LOW power limits  

  

  

   

Hi had the Jabiru 2200.  Had lots of problems with noise, engine and electrical from spark plugs etc.  I did not like the noise and was hard to hear on intercom.  The guy who bought it put on a different prop hoping for better performance but sent it back.  You can only go so far with a VW type direct drive engine with props.  I had a 912UL and was happy with it.  It was in a Model IV and performed great.  The guys at the airport asked why I would want anything else.  When my friend flys with me he comments how quiet the aircraft is.  With 2 of us in his Avid it would climb almost as good as a 150 with 2 people. 

  

 Clint

 

       

  

From: jcrowder(at)lpbroadband.net

 To: kitfox-list(at)matronics.com

 Subject: RE: Re: LOW power limits

 Date: Fri, 11 Jan 2008 19:11:45 -0700    

Which Jabiru engine did he have?  How well was it set up and did he have 100 hours one it.  Many Jab owners say their engine continues to perform better up through the first 100 hours.  To get their performance Rotax owners often resort to more expensive and complex adjustable props.  What is the difference in the part count?  And of course performance will be better with a Jabiru 3300, 120 hp engine, than with a Jabiru 2200, 80 hp engine.  Older and newer Jabiru models also have different carburetor jetting among other engine changes.  It will be a while before we really know how these engines match up and maintain.  All of us have an interest in the engines we invest in.   I submit to you that it is rare to have someone not advocate the engine they know and own.  Likewise our research tends to lead to the outcome we expect.    

    

   

    

In the end we are fortunate to have more good engine choice than ever before.  

    

   

    

Jim Crowder  

    

   

    

   

  [quote]  

--

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

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