C-145 / 0-300 Engine TBO

cessna170bdriver · Post by **cessna170bdriver** » Thu Sep 28, 2006 2:25 pm

blueldr wrote:Bill Hart,

If you fly that airplane enough on Mogas, it will not only save you enough to pay your club dues but will also pay for the next overhaul!

Your mileage may vary. Mine did.

Miles

Post by **GAHorn** » Thu Sep 28, 2006 8:11 pm

cessna170bdriver wrote:
blueldr wrote:Bill Hart,

If you fly that airplane enough on Mogas, it will not only save you enough to pay your club dues but will also pay for the next overhaul!
Your mileage may vary. Mine did.

Miles

Yeah! Surely the ETHANOL they put in autogas these days isn't the kind of alcohol Cessna prohibits in the Type Certificate.

Robert Eilers · Post by **Robert Eilers** » Thu Sep 28, 2006 9:48 pm

When I was flying my Champ with an Auto gas STC it got to the point I just could not find auto gas without alcohol in it - at least in Caifornia. Gave up and starting using 100LL with TCP. I know guys who arn't even checking anymore. I guess saving $2.00 a gallon is to big a temptation. Short sighted if you ask me. A $2.00 a gallon savings may amount to about $3,000 if you average 200 hrs a year. But, how many years of savings would it take to recover from alcohol damage to the fuel system or engine?

trake · Post by **trake** » Thu Sep 28, 2006 11:38 pm

Does anybody know if the new top-ends theyre making now [ECI and Superior] handle 100LL better than the old Continental cylinders/valves/pistons? Everytime I use 100LL I get bad mag checks-I have Millennium cylinders.

Thu Sep 28, 2006 11:41 pm

Robert Eilers wrote: But, how many years of savings would it take to recover from alcohol damage to the fuel system or engine?

It could be argued, and I wouldn't doubt the EAA is doing just that, that specially in a Champ or Cub there won't be any damage.

Time will tell but I wouldn't be surprised if at some time in the future some aircraft will be approved for amounts of ethanol. After all there is today a few aircraft approved for E-85 which is nearly 85% ethanol. but this is getting way off the subject.

blueldr · Post by **blueldr** » Fri Sep 29, 2006 2:34 am

George,

What kind of fuel did Cessna specify in the type certificate? Is it available now? Did they make 100LL fuel back then?

Post by **GAHorn** » Fri Sep 29, 2006 3:48 am

blueldr wrote:George,

What kind of fuel did Cessna specify in the type certificate? Is it available now? Did they make 100LL fuel back then?

Directly from page one of the Type Certificate Data Sheet for Cessna 170 aircraft:

WARNING: Use of alcohol-based fuels can cause serious performance degradation and fuel system component damage, and is therefore prohibited on Cessna airplanes.

cessna170bdriver · Post by **cessna170bdriver** » Fri Sep 29, 2006 9:42 am

gahorn wrote:
cessna170bdriver wrote:
blueldr wrote:Bill Hart,

If you fly that airplane enough on Mogas, it will not only save you enough to pay your club dues but will also pay for the next overhaul!
Your mileage may vary. Mine did.

Miles
Yeah! Surely the ETHANOL they put in autogas these days isn't the kind of alcohol Cessna prohibits in the Type Certificate.

I'm pretty sure alcohol wasn't the problem (87 octane name-brand in Mississippi in the early '90s). I could detect absolutely no change in performance or fuel consumption, but I was having cylinder problems every few hundred hours with stuck valves and rings due to carbon. Also, exhaust pipes always ran sooty. No amount of leaning seemed to help.

Bill Hart · Post by **Bill Hart** » Fri Sep 29, 2006 12:18 pm

gahorn wrote:
cessna170bdriver wrote:
blueldr wrote:Bill Hart,

If you fly that airplane enough on Mogas, it will not only save you enough to pay your club dues but will also pay for the next overhaul!
Your mileage may vary. Mine did.

Miles
Yeah! Surely the ETHANOL they put in autogas these days isn't the kind of alcohol Cessna prohibits in the Type Certificate.

I have never had a problem with alcohol in my gas....I always but my beer down before I fill up.

Just joking. I have been seeing the ethanol signs comming down here lately. I was wondering if the stickers were coming off or they really donâ€™t have the ethanol in the gas. At more than one Enmark down here the stickers are off of the 87 but are still on the higher octane fuels.

blueldr · Post by **blueldr** » Sat Sep 30, 2006 2:41 am

Every fuel I've tested, branded and unbranded, here in the Golden State lately has tested at 5% alcohol. When I run into a problem, I'll let the members know.
My cars, emergency generator, air compressor. ATV, and airplane seem to digest it OK, but I seem to get some resistence from my chain saw. It still seems to thrive on AVGAS. Thank god I dont have to heat my home on fire wood!

Post by **GAHorn** » Sat Sep 30, 2006 2:39 pm

We've discussed this before, but just to reiterate... The problem with alcohol imho is:
1- It attracts/absorbs moisture. Airplanes go up and down and as the fuel is consumed the ullage is made up of moist atmosphere. If you're lucky it'll condense out and your gascolator won't become overburdened. If you're average, the water will remain in suspension/emulsion until some cool day when you lose the engine on takeoff (as occured to me one day when flying my AP/IA's airplane which used mogas almost exclusively. It was a nighttime takoff but fortunately it was also at Dallas Love field with miles of runway still before me.)

2- Alcohol is corrsosive and aggressively attacks most synthetic rubber components of the fuel system and rusts steel and attacks aluminum making it porous. The disappointment you will eventually have when you find your carburetor is not worthy of flight OR useable as a core-deposit will go a long way to detracting from any savings you might have imagined using alcohol fuels.

3- The accident caused by any malfunction of your engine, whether or not related to the fuel, will be focused around your violation of the aircraft type certificate, the violation of aircraft limitations, and the violation of the auto-gas STC (if any). (In which case you'd have been better off spending your insurance premiums on avgas and tcp, because it's likely they'll not pay for any damage/injuries/lawsuits issuing from the accident.)

cessna170bdriver · Post by **cessna170bdriver** » Sat Sep 30, 2006 6:04 pm

gahorn wrote:We've discussed this before, but just to reiterate... The problem with alcohol imho is:
1- It attracts/absorbs moisture. Airplanes go up and down and as the fuel is consumed the ullage is made up of moist atmosphere. If you're lucky it'll condense out and your gascolator won't become overburdened. If you're average, the water will remain in suspension/emulsion until some cool day when you lose the engine on takeoff (as occured to me one day when flying my AP/IA's airplane which used mogas almost exclusively. It was a nighttime takoff but fortunately it was also at Dallas Love field with miles of runway still before me.)

2- Alcohol is corrsosive and aggressively attacks most synthetic rubber components of the fuel system and rusts steel and attacks aluminum making it porous. The disappointment you will eventually have when you find your carburetor is not worthy of flight OR useable as a core-deposit will go a long way to detracting from any savings you might have imagined using alcohol fuels.

3- The accident caused by any malfunction of your engine, whether or not related to the fuel, will be focused around your violation of the aircraft type certificate, the violation of aircraft limitations, and the violation of the auto-gas STC (if any). (In which case you'd have been better off spending your insurance premiums on avgas and tcp, because it's likely they'll not pay for any damage/injuries/lawsuits issuing from the accident.)

Avgas seems to work best in my airplane, so that's what I put in it. I just wonder how automobile designers have gotten around these apparent problems with mogas. My 1997 Saturn is made of aluminum, rubber, and steel, and has digested over 9000 gallons of mogas (every drop execept what it left the factory with has been purchased in California) without apparent detriment.

Post by **GAHorn** » Sat Sep 30, 2006 7:58 pm

The specific alloys in your Saturn are designed in anticipation of alcohol in the fuel. (Aviation fuel system parts are not...the specific alloys, and rubber blends in aviation do not anticipate the use of alcohol except in rare cases of aircraft with alcohol de-icing systems designed into the fuel system.... usually turbine equipment. The Rolls-Royce Viper comes to mind. That engine used methanol to deice the fuel filters prior to high-altitude, low-power descents. Anyone wishing to see the alcohol pump from a Viper powered airplane can look at it in my garage. The aluminum parts of it are eaten up with corrosion and required regular overhaul/replacement....that's how I came to have this one. Many early transport category aircraft used water/methanol injection systems, but that blend was confined to the injection system, not the fuel storage system.)
Alcohol in autogas is nothing new. It's been used for years and it also was used even in the early days in winter blends for anti-icing purposes. For that reason, many auto systems accomodate alcohol thru the use of high-nickle content steels and specialized rubber, although there are many autos in the 1960 thru 1985 model years that do not. Alcohol-blended fuels ruined the fuel-tank located pumps in most early and mid-80's Ford products in short order. Mobil oil company paid lots of money in damages in a class action suit in Texas for blending alcohol without notice in 1985-87. I was sent a $420 check from them for potential damages to my 1983 Mercury Grand Marquis, to replace the fuel pump.
Alcohol has always been avoided in aviation fuels for several reasons, the most important being that airplanes typically consume fuel at higher hourly rates. This means the fuel tanks (which are also subject to larger temperature excursions due to altitude changes) are more likely to condense greater quantities of water which will be adversely affected by any alcohol in the fuel.