If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
|
Thread Tools | Display Modes |
#11
|
|||
|
|||
AvGas vs. Regular gas for Pawnee?
That's what we are running also Frank.. but we changed from the 1A200
propeller to the 1P235 propeller, both listed on the TCDS for the PA-25 with the O-540 engine. The 1P235 is lighter in weight and also provides an additional 60fpm climb rate at max GW. We are running about 1250 lbs below Max GW in our tow configuration. The old propeller was totaled in the prop strike which drove us to a rebuild on the engine. BT "Frank Whiteley" wrote in message oups.com... Synopsis from our chief tow pilot "Per Howard Kron's current STC (which I bought and is our basis): Higher compression pistons (but not actually THAT high; 90/96 or 100LL required); RPM max still 2575, same as 235; prop replaced due to hub damage ..... which was not previously picked up, and Factory New prop pitched to the original factory 84-52 (had been whacked back to ~49 pitch). Net effect, much stronger, climbs like a raped ape. The AirCare twicepipes (i.e., dual exhaust, NO!! mufflers) STC probably helps significantly, too. In our operation, 65-68kts TAS is right at redline. If anyone wants faster, they'll climb slower, owing to too-flat AOT, and probably have to throttle back to stay legal." I recall some discussion that the 250 STC is probably a better option than the 260 (we couldn't find a core), as the 260 has a jump in fuel burn for the extra 10hp. Apparently a lot of the 260hp cores are on those air boats we all saw in Louisiana and Mississippi after Katrina, with no maintenance records and a lot of swamp water exposure. Frank Whiteley |
#12
|
|||
|
|||
AvGas vs. Regular gas for Pawnee?
We burned auto gas in 235 Pawnees 150 Super cub and 230 hp C-182e for
20 years and an estimated 15,000+ hours . Up side: We never had an engine that did not make it to TBO. ( At least 8 engines that I can recall) We had 4 mid life cylinder changes do to cylinder head cracks. (4 cylinders total!) We saw no difference in performance over 100ll. No- lead fouling and build up in spark plugs. As a conservative estimate, we burned over 240,000 gallons with an average savings of 1.50 per gallon ( when I figure the off road gas tax refund) is roughly $360,000.00 over 20 years. This is about what my fleet of 8 aircraft is worth today. Down side: Mo gas stinks. Burns dirty. Leaves black soot on belly instead of gray. Some times it is difficult to get a fuel company to agree to sell it for the use in aircraft. I had to switch back to AV gas last year because in California MTBE fuels are outlawed and Alcohol based fuels are not approved for airplanes ( alcohol suspends water). It was a nice run while it lasted. I should mention that we operate from a near sea level, 2000 ft runway and find that 235 HP is quite adequate. Rex Mayes Williams Soaring Center, Williams Ca (formerly Lagoon Valley Soaring, Vacaville Ca) |
#13
|
|||
|
|||
AvGas vs. Regular gas for Pawnee?
Nevada still has real auto gas, at least in Douglas County (Minden).
Has anyone tried using water to remove the alcohol in California gas? To do that, you'd need to agitate the fuel water mixture, the alcohol has a higher affinity to water than to gasoline, so comes out of suspension in the gas and joins the water. Drain water/alcohol from bottom of tank and what remains should be usable gasoline. bumper "Rex" wrote in message ups.com... We burned auto gas in 235 Pawnees 150 Super cub and 230 hp C-182e for 20 years and an estimated 15,000+ hours . Up side: We never had an engine that did not make it to TBO. ( At least 8 engines that I can recall) We had 4 mid life cylinder changes do to cylinder head cracks. (4 cylinders total!) We saw no difference in performance over 100ll. No- lead fouling and build up in spark plugs. As a conservative estimate, we burned over 240,000 gallons with an average savings of 1.50 per gallon ( when I figure the off road gas tax refund) is roughly $360,000.00 over 20 years. This is about what my fleet of 8 aircraft is worth today. Down side: Mo gas stinks. Burns dirty. Leaves black soot on belly instead of gray. Some times it is difficult to get a fuel company to agree to sell it for the use in aircraft. I had to switch back to AV gas last year because in California MTBE fuels are outlawed and Alcohol based fuels are not approved for airplanes ( alcohol suspends water). It was a nice run while it lasted. I should mention that we operate from a near sea level, 2000 ft runway and find that 235 HP is quite adequate. Rex Mayes Williams Soaring Center, Williams Ca (formerly Lagoon Valley Soaring, Vacaville Ca) |
#14
|
|||
|
|||
AvGas vs. Regular gas for Pawnee?
I think we may be on the wrong track here. If water is suspected in a cars
fuel system, you add ethanol to get rid of it. The alcohol combines with the water and then with the gasoline. With enough ethanol present, the water/ethanol mixes with gasoline and is burned away. It used to be when there was no ethanol in gasoline, water would condense in the tanks and freeze in cold weather blocking the fuel system. You could buy cans of "fuel anti-freeze" (ethanol) at auto parts stores to get rid of the water. Now all auto fuel contains some ethanol anyway so no need to use the stuff. As I understand it, the reason ethanol in airplane fuel is bad is that it dissolves aluminum and makes elastomer seals in the fuel system swell until leaks appear. A couple of tries to burn straight ethanol back in the 1970's resulted in badly damaged airplanes. Bill Daniels "bumper" wrote in message ... Nevada still has real auto gas, at least in Douglas County (Minden). Has anyone tried using water to remove the alcohol in California gas? To do that, you'd need to agitate the fuel water mixture, the alcohol has a higher affinity to water than to gasoline, so comes out of suspension in the gas and joins the water. Drain water/alcohol from bottom of tank and what remains should be usable gasoline. bumper "Rex" wrote in message ups.com... We burned auto gas in 235 Pawnees 150 Super cub and 230 hp C-182e for 20 years and an estimated 15,000+ hours . Up side: We never had an engine that did not make it to TBO. ( At least 8 engines that I can recall) We had 4 mid life cylinder changes do to cylinder head cracks. (4 cylinders total!) We saw no difference in performance over 100ll. No- lead fouling and build up in spark plugs. As a conservative estimate, we burned over 240,000 gallons with an average savings of 1.50 per gallon ( when I figure the off road gas tax refund) is roughly $360,000.00 over 20 years. This is about what my fleet of 8 aircraft is worth today. Down side: Mo gas stinks. Burns dirty. Leaves black soot on belly instead of gray. Some times it is difficult to get a fuel company to agree to sell it for the use in aircraft. I had to switch back to AV gas last year because in California MTBE fuels are outlawed and Alcohol based fuels are not approved for airplanes ( alcohol suspends water). It was a nice run while it lasted. I should mention that we operate from a near sea level, 2000 ft runway and find that 235 HP is quite adequate. Rex Mayes Williams Soaring Center, Williams Ca (formerly Lagoon Valley Soaring, Vacaville Ca) |
#15
|
|||
|
|||
AvGas vs. Regular gas for Pawnee?
"Bill Daniels" wrote in message ... I think we may be on the wrong track here. If water is suspected in a cars fuel system, you add ethanol to get rid of it. The alcohol combines with the water and then with the gasoline. With enough ethanol present, the water/ethanol mixes with gasoline and is burned away. A common method to test gasoline for presence of alcohol is to put a small amount of water, about 10% by volume, in a test tube or similar container. Add suspect gasoline and shake. If the water level appears to rise, it's due to alcohol coming out of solution with the gasoline and joining with the water. If there's no alcohol, the water level remains the same. bumper |
#16
|
|||
|
|||
AvGas vs. Regular gas for Pawnee?
Bumper and Bill,
I am not a chemical engineer but I think that you are both on the right track. The ethanol aborsbs the water and thus makes it 'burnable' but I think it still is in the bottom of the tank. Corrections welcome. I do remember that we used to pour straight water into the carburetor to 'clean' the exhaust valves! Made it run rough for a second or two but really did a good job of steam cleaning the carbon off of them!) At 05:18 01 December 2005, Bumper wrote: 'Bill Daniels' wrote in message ... I think we may be on the wrong track here. If water is suspected in a cars fuel system, you add ethanol to get rid of it. The alcohol combines with the water and then with the gasoline. With enough ethanol present, the water/ethanol mixes with gasoline and is burned away. A common method to test gasoline for presence of alcohol is to put a small amount of water, about 10% by volume, in a test tube or similar container. Add suspect gasoline and shake. If the water level appears to rise, it's due to alcohol coming out of solution with the gasoline and joining with the water. If there's no alcohol, the water level remains the same. bumper |
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Avgas STC | Mike Granby | Owning | 12 | September 6th 05 07:18 PM |
Your free AvGas fillup at Dodge Center MN (TOB) July Sunday 31, AM | abripl | Piloting | 121 | August 10th 05 01:08 PM |
Avgas price and the light plane ownership | M | Owning | 56 | July 10th 05 04:55 AM |
Avgas Prices | aluckyguess | Piloting | 14 | May 6th 05 07:23 AM |
Regular Passenger Service From San Jose to Sacramento? | CHANGE USERNAME TO westes | Piloting | 23 | November 28th 04 04:10 AM |