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bob.kravis(at)gmail.com
Guest

Posted: Fri Feb 26, 2010 2:49 pm Post subject: Fuel Reserve and UL's

I was reading through the AOPA site because I had a question about fuel reserve and flight distance in a 447 powered UL.  In response to a letter to the editor questioning the necessity of landing with "adequate reserve,"  the editor replied: It is our opinion that upon landing, every VFR flight should have at least 30 minutes worth of fuel in the tanks. And if flying cross-country, should the pilot need to tap into the required VFR fuel reserve, it constitutes an "emergency," and the pilot should be looking for the closest airport and gas pump. (Ideally, the pilot should have landed and refueled long before tapping into the 30-minute VFR reserve.) - Ed.

 Now looking at the Rotax performance charts I see something like 5.5 gph at 6,000 rpm and assuming a UL will be cruising at 63 mph, in still air one would have only 2.25 gal.'s of a full 5 gal. tank to fly off.  That's only 27 minutes of flying time at that consumption rate.  You couldn't make a 30 mi. flight to a neighboring airport!  I know that greatest endurance would be at a lower rpm but how big a difference? 4.5 gph (at) 50 mph?

 What is your real world experience?

Bob

  [quote][b]

lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Fri Feb 26, 2010 3:13 pm Post subject: Fuel Reserve and UL's

Perhaps you were looking at the wrong chart. I had a 582  that would burn 5 GPH but my 447 never burned more than 3 GPH or less. I do know  for certain on a Firestar 2 and the 447 I regularly got 20 miles per gallon. I  can assure you that I also flew at 6000 rpm's.

 Larry

 Note: If you forward this email, please delete the forwarding history,  which includes my email address.

 [quote]   ---

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Dana

Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA

Posted: Fri Feb 26, 2010 3:28 pm Post subject: Fuel Reserve and UL's

At 05:47 PM 2/26/2010, Bob Kravis wrote:



  	  Quote: 	
		  It is our opinion that upon landing, every VFR flight should have at least 30 minutes worth of fuel in the tanks. And if flying cross-country, should the pilot need to tap into the required VFR fuel reserve, it constitutes an "emergency,"..

 What is your real world experience? 	


 A 30 minute reserve may be fine for a GA aircraft that needs a 2000' (or more) paved runway to land, but is hardly necessary for a UL or UL-like aircraft that can land nearly anywhere.



  From any random point in the US, how far (in time) would you have to fly to reach a suitable airport for a GA plane?  How far (again, in time) would you have to fly to where you can make a safe landing in a Kolb?



 If the latter number doesn't agree with the glide ratio and your altitude, you don't fly like I do.



 -Dana

 

 --

  Hard work has a future payoff.  Laziness pays off now.    [quote][b]

bob.kravis(at)gmail.com
Guest

Posted: Fri Feb 26, 2010 3:47 pm Post subject: Fuel Reserve and UL's

Larry,Here's the chart I was looking at (see attached).Bob



On Fri, Feb 26, 2010 at 5:47 PM, Bob Kravis <bob.kravis(at)gmail.com (bob.kravis(at)gmail.com)> wrote:

  	  Quote: 	
		  I was reading through the AOPA site because I had a question about fuel reserve and flight distance in a 447 powered UL.  In response to a letter to the editor questioning the necessity of landing with "adequate reserve,"  the editor replied:  It is our opinion that upon landing, every VFR flight should have at least 30 minutes worth of fuel in the tanks. And if flying cross-country, should the pilot need to tap into the required VFR fuel reserve, it constitutes an "emergency," and the pilot should be looking for the closest airport and gas pump. (Ideally, the pilot should have landed and refueled long before tapping into the 30-minute VFR reserve.) - Ed.

  Now looking at the Rotax performance charts I see something like 5.5 gph at 6,000 rpm and assuming a UL will be cruising at 63 mph, in still air one would have only 2.25 gal.'s of a full 5 gal. tank to fly off.  That's only 27 minutes of flying time at that consumption rate.  You couldn't make a 30 mi. flight to a neighboring airport!  I know that greatest endurance would be at a lower rpm but how big a difference? 4.5 gph (at) 50 mph?

  What is your real world experience?

Bob

    	  Quote: 	
		  



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lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Fri Feb 26, 2010 4:36 pm Post subject: Fuel Reserve and UL's

It might be the right chart, but the results are wrong.  They just don't burn that much gas. Anyone had that kind of usage on a 447? I am  not experienced in a Firefly, but I can't see you using that amount of fuel  at any setting under 6200. You should be able to fly 60 to 70 miles and still  have a gallon of fuel left.

  

 Your best bet would be to do some checking on your own  before you wander off to MV. I would take it up and fly around in the pattern,  same altitude, same setting, timing your flight, land and check the fuel used.  If there is no way to monitor the fuel used, start with a 30 minute flight. Once  you figure out your consumption at say 6000 RPM, then you can check to see what  setting will conserve the most fuel and still give you a suitable power  setting.

 Larry

  

  

 Note: If you forward this email, please delete the forwarding history,  which includes my email address.

 [quote]   ---

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elleryweld(at)aol.com
Guest

Posted: Fri Feb 26, 2010 5:12 pm Post subject: Fuel Reserve and UL's

Bob when I had the firestar Fat but Clean with a 447 on it I was getting 3 to 3.3GPH (at) 75MPH 

 

     Ellery Batchelder Jr.

 

 

 

   --

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Fri Feb 26, 2010 5:33 pm Post subject: Fuel Reserve and UL's

Ellery B/Gang:

  

 What rpm?

  

 Was that cruise power on a cross country? or flying around the  patch?

  

 john hauck

 mkIII

 Titus, Alabama

  

 [quote]    

Bob when I had the    firestar Fat but Clean with a 447 on it I was getting 3 to 3.3GPH (at) 75MPH    



      Ellery Batchelder    Jr.

 [b]

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Fri Feb 26, 2010 5:33 pm Post subject: Fuel Reserve and UL's

Larry C/Gang:

  

 My single carb point ign 447 burned 3.5 to 3.75 gph at 5800  rpm cruise power on cross country flights.

  

 john hauck

 mkIII

 Titus, Alabama

  

  

  	  Quote: 	
		      

   It might be the right chart, but the results are wrong. They just don't    burn that much gas. Anyone had that kind of usage on a 447? 

   Larry

    

    

    

	
   [quote][b]

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

herbgh(at)nctc.com
Guest

Posted: Fri Feb 26, 2010 5:50 pm Post subject: Fuel Reserve and UL's

I have my logs and they indicate anywhere from 2.3  to 3.3 gph   447 on a firefly...with an empty wt of 292 lbs...  ..Herb 



 

 At 06:32 PM 2/26/2010, you wrote:

 [quote]It might be the right chart, but the results are wrong. They just don't burn that much gas. Anyone had that kind of usage on a 447? I am not experienced in a Firefly, but I can't see you using that amount of fuel at any setting under 6200. You should be able to fly 60 to 70 miles and still have a gallon of fuel left.

  

 Your best bet would be to do some checking on your own before you wander off to MV. I would take it up and fly around in the pattern, same altitude, same setting, timing your flight, land and check the fuel used. If there is no way to monitor the fuel used, start with a 30 minute flight. Once you figure out your consumption at say 6000 RPM, then you can check to see what setting will conserve the most fuel and still give you a suitable power setting.

 Larry

  

  

 Note: If you forward this email, please delete the forwarding history, which includes my email address.

   ---

Dana

Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA

Posted: Fri Feb 26, 2010 5:51 pm Post subject: Fuel Reserve and UL's

At 08:07 PM 2/26/2010, Ellery Batchelder Jr wrote:

  	  Quote: 	
		  Bob when I had the firestar Fat but Clean with a 447 on it I was getting 3 to 3.3GPH (at) 75MPH 	


 My US with the Cuyuna burns 3.3 gph at cruise (56-5800 rpm).



 -Dana

 --

  But it's NOT an ASSAULT Weapon, it's a DEFENSE weapon!    [quote][b]

Richard Pike

Joined: 09 Jan 2006
Posts: 1671
Location: Blountville, Tennessee

Posted: Fri Feb 26, 2010 6:15 pm Post subject: Re: Fuel Reserve and UL's

This is why (IMO) bigger 2 strokes are better. I have a 582 in my MKIII, and at 65 mph and 5300 rpm, it burns about 4 gph or a hair less. Ed has a 582 on his FSII, and at the same speed he turns 5,000 and burns about 3.6 gph. 



When I flew to Oshkosh years ago, Ed & Dave had Drifters with 503's. To stay slow enough to not run away from the Drifters, I was turning the 532 about 5,000, they were running around 5,600 rpm. I consistently used less fuel than they did, even though I had dual carbs and they each just had one.



Richard Pike

MKIII N420P (420ldPoops)

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Fri Feb 26, 2010 6:19 pm Post subject: Fuel Reserve and UL's

My Cuyuna ULII02 burned 3.5 gph at 5800 rpm on cross country  flights.

  

 Any aircraft flying around the patch, shooting take offs and  landings will burn much less than they do on a cross country.  Many new  pilots are surprised when the find out their engines are burning more than they  thought they would.

  

 john hauck

 mkIII

 Titus, Alabama

  

  

 [quote]    My US with the Cuyuna burns 3.3 gph at    cruise (56-5800 rpm).



-Dana



    

[b]

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Fri Feb 26, 2010 6:43 pm Post subject: Fuel Reserve and UL's

This is why (IMO) bigger 2 strokes are better. I have a 582 in my MKIII, and 

at 65 mph and 5300 rpm, it burns about 4 gph or a hair less. Ed has a 582 on 

his FSII, and at the same speed he turns 5,000 and burns about 3.6 gph.



When I flew to Oshkosh years ago, Ed & Dave had Drifters with 503's. To stay 

slow enough to not run away from the Drifters, I was turning the 532 about 

5,000, they were running around 5,600 rpm. I consistently used less fuel 

than they did, even though I had dual carbs and they each just had one.



Richard Pike





Richard P/Gang:



I flew all my two strokes at 5800 rpm cruise.



My 582 powered mkIII cruised 80 mph at 5800 rpm and burned 5.5 gph.



My 447 powered FS cruised (can not remember the cruise speed) at 5800 rpm 

and burned 3.5 to 3.75 gph.



My ULII02 powered US cruised (can not remember the cruise speed) at 5800 rpm 

and burned 3.5 gph.



My 912UL powered mkIII cruised 85 mph at 5,000 rpm and burned 4.0 gph.



My 912ULS powered mkIII cruises at 88 mph at 5,000 rpm and burns 5.0 gph.



I flew/fly all my two and four stroke engines at aprx'ly 75% power.  They 

all were happy at that power setting and the airplanes and I were too.



john hauck

mkIII

Titus, Alabama

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Fri Feb 26, 2010 6:45 pm Post subject: Fuel Reserve and UL's

Didn't finish the sentence below in my previous.

  

 "Many new pilots are surprised when they find out their  engines are burning more during an actual longer cross country than they thought  they would.

  

 john hauck

 mkIII

 Titus, Alabama

  

  

  

 [quote]     Many new pilots are surprised when the find out    their engines are burning more than they thought they would.

    

    

[b]

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

jbhart(at)onlyinternet.ne
Guest

Posted: Fri Feb 26, 2010 6:59 pm Post subject: Fuel Reserve and UL's

Bob,



When I had a 447 mounted on the FireFly, I flew it 108 mile round trips to 

my EAA Chapter meetings.  The average for nine trips is given below.



5.71 Gallons burned per round trip

MPG - 18.9

Air Time - 112 minutes

GPH - 3.06

4/4.5 gallon endurance - 78/88 minutes

Speed ground to ground - 57.9 mph

4/4.5 gallon range - 75/85 miles



I hope this helps you out.



Jack B. Hart FF004

Winchester, IN

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Fri Feb 26, 2010 7:08 pm Post subject: Fuel Reserve and UL's

When I had a 447 mounted on the FireFly, I flew it 108 mile round trips to

my EAA Chapter meetings.  The average for nine trips is given below.



5.71 Gallons burned per round trip

MPG - 18.9

Air Time - 112 minutes

GPH - 3.06

4/4.5 gallon endurance - 78/88 minutes

Speed ground to ground - 57.9 mph

4/4.5 gallon range - 75/85 miles



I hope this helps you out.



Jack B. Hart FF004

*******************

Hi Guys:



When you all are contributing info on fuel burn, need to include power 

setting, i.e., engine rpm.  There is a great deal of difference in fuel burn 

on two and four stroke aircraft engines at low power settings and higher 

power settings.  To me, 75% power is normal cruise.  Seems most of the 

others who have contributed info on fuel burn, cruise much slower.



john hauck

mkIII

Titus, Alabama

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

capedavis(at)yahoo.com
Guest

Posted: Fri Feb 26, 2010 7:19 pm Post subject: Fuel Reserve and UL's

John /Ellery/gang I flew my very clean Firestar KXP for ten years with a 503 and mostly saw 3.5  gal/hr BUT only saw 75mph on a long decent 65 mph most of the time was my straight and level speed

 

Chris Davis

KXP 503 492 hrs

Glider Pilot

Disabled from crash building Firefly  



 

   From: John Hauck <jhauck(at)elmore.rr.com>

To: kolb-list(at)matronics.com

Sent: Fri, February 26, 2010 8:20:51 PM

Subject: Re: Fuel Reserve and UL's



   Ellery B/Gang:

  

 What rpm?

  

 Was that cruise power on a cross country? or flying around the patch?

  

 john hauck

 mkIII

 Titus, Alabama

  

 [quote]  

Bob when I had the firestar Fat but Clean with a 447 on it I was getting 3 to 3.3GPH (at) 75MPH 



  Ellery Batchelder Jr.

 -============================================


[b]

elleryweld(at)aol.com
Guest

Posted: Fri Feb 26, 2010 8:42 pm Post subject: Fuel Reserve and UL's

that was Cruise on cross country  if I remember correctly around 5600 RPM  (at) 6250 RPM in Flat level flight I could get 97.3 MPH around 4.5 GPH  

 

 

     Ellery Batchelder Jr.

 

 

 

   --

NeilsenRM(at)comcast.net
Guest

Posted: Fri Feb 26, 2010 9:11 pm Post subject: Fuel Reserve and UL's

Bob

  

 It really depends on the situation. Determine  YOUR fuel burn. If you test your fuel system so you know when fuel runs out  and you know your fuel gage is always accurate yes you can cut the minimums a  bit. I say that but again it depends on what you are doing. I had a cross  country flight in the UP of Michigan where there was no where to land. I was  less than 2 miles to my fuel stop and I ran into a wall of fog. I had to turn  around and fly almost an hour to find another runway. 

  

 I have the standard 10 gallon tanks. When traveling  I add a 6 gallon aux tank which I transfer in flight as soon as I can. I plan my  fuel stops so that I have no less than 5 gallons on board and I burn 4 gal./hr.  Running out of fuel in the air is a REALLY STUPID thing to do.

  

 Rick Neilsen

 Redrive VW Powered MKIIIC

 [quote]   ---

Richard Pike

Joined: 09 Jan 2006
Posts: 1671
Location: Blountville, Tennessee

Posted: Fri Feb 26, 2010 9:50 pm Post subject: Re: Fuel Reserve and UL's

 	  John Hauck wrote: 	
		  



Richard P/Gang:



I flew all my two strokes at 5800 rpm cruise.



My 582 powered mkIII cruised 80 mph at 5800 rpm and burned 5.5 gph.



My 447 powered FS cruised (can not remember the cruise speed) at 5800 rpm 

and burned 3.5 to 3.75 gph.



My ULII02 powered US cruised (can not remember the cruise speed) at 5800 rpm 

and burned 3.5 gph.



My 912UL powered mkIII cruised 85 mph at 5,000 rpm and burned 4.0 gph.



My 912ULS powered mkIII cruises at 88 mph at 5,000 rpm and burns 5.0 gph.



I flew/fly all my two and four stroke engines at aprx'ly 75% power.  They 

all were happy at that power setting and the airplanes and I were too.



john hauck

mkIII

Titus, Alabama 	




Happy for ya. If I was going half way across the country, I would ignore how much gas it burns and how comparatively unpleasant the ride is at 80 and run it at 5800 rpm too. Going to Oshkosh in the MKIII along with two pokey 503 powered Maxair Drifters had me running at 5,000 rpm and took 3 days. (groan)



But since I am usually only going 30 or 40 miles to drop in on a local airstrip, and a MKIII with it's light wing loading enjoys leaping briskly about on a thermally day, 60 or 65 is a lot nicer, saves gas, and saves me from barfing. Since I only fly for pleasure, not to get somewhere, rolling with the thermal punches at 65 is nicer than playing "Test the shoulder harness" at 80. 



Aint it great? We can all butter our bread as it suits us.



And since crankshaft bearing loads go up exponentially with RPM, I am satisfied that a correctly propped 2 stroke will be happy anywhere in the RPM range, and the crank will last longer at 5,300 than at 5,800.  I treat my 582 gently and with respect and I expect it to do the same for me.    



(John, I think we've had this dance before, and still can't seem to agree if it's a Cha-Cha or a Foxtrot... Hang in there buddy -  two strokes are evil and must be PUNISHED!)



Richard Pike

MKIII N420P (420ldPoops)

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