O-300 и автобензин

[ilya]

Уважаемое сообщество!
подскажите-можно ли эксплуатировать O-300 на автобензине
для Лайкомингов где то на форуме была оффициальная информация, а про Континентали ничегоне нашел
Спасибо

[lt.ak]

http://www.autofuelstc.com/autofuelstc/ ... gines.html

http://www.eaa.org/autofuel/autogas/approved.asp

но не забывайте что они approved когда со соответствующим STC ... и все ссылки относятся к сертификации FAA ...

[Kurt]

Привожу цитату с одного форума, похоже что человек понимает о чем пишет. В pdf официальная позиция производителя.

Pilot DAR
5th Jan 2008, 21:13
I had great success over the years operating a number of aircraft on Mogas. I did all of the evaluation and testing required to convert a TCM IO-520D to be carburetted, and approve it to use Mogas in a Cessna 185. This was a complete success, and the aircraft flew for many years this way with no limitations. It ceased flying only due to pilot error, nothing to do with the fuel.

There are some engine/airframe combinations which cannot handle Mogas safely, and experimentation is a bad idea. If it is approved, get the approval, and follow the instructions. If it's not approved by now, forget it, it won't be worth the effort to approve it, even if it is possible.

My total flying experience on Mogas exceeds 3500 hours, as high as 20,000', and at temperatures exceeding 100F. I have been careful, and never had any unfavourable event associated with Mogas use.

In my Cessna 150, it is extremely better than 100LL in terms of not sticking exhaust valves. A former Cessna employee whom I knew, also a 150 owner, was a real proponent of Mogas, because of his experience with valve problems in his plane. He taught me a lot about this, and authored a very good book on the subject.

Avgas and Mogas differ in many ways. One important way is that Mogas is a blend of many different liquids to create the desired properties, where Avgas is only one liquid. This is why when Mogas evaporates, gum is often left. Think of it as the difference between clean water and a soft drink. When the water evaporates, it's all gone and the glass is clean and dry. when a soft drink evaporates, it goes flat first (very volatile parts gone first) once this happens to Mogas, starting is more difficult (stale gas) but there's still liquid there, once that liquid evaporates, gum is left. Adding fresh gas gets things right again. You'll notice that when Avgas evaporates, it all goes at once, and only a dry (poisonous) film is left.

Refer to Transport Canada's publication TP10737, it has a lot of useful information.

What follows is a cut and paste of an article I wrote on this subject 15 years ago:

Pilot DAR

GASOLINE AND YOUR ENGINE

Gasoline is one of those things we use so much of, we really seem to take it for granted. Certainly, with the exception of water from time to time, gasoline is a very reliable aviation product- it just about always does what it is supposed to. During the years when we flew on Avgas only, we really took it for granted. Now, with the wide spread use of Mogas, we are paying a bit more attention. It is a widely agreed statistic that
the users of Mogas have far fewer cases of running out of gas in flight. This has been attributed to the simple fact that those pilots were more aware of their fuel situation. There were probably cases where a particular aircraft was not approved for that fuel, and the forced landing might attract unwanted attention to the use of Mogas.
At present, with the exception of 80/87, we have the greatest choice of gasolines, suppliers, and prices that we have ever had. To help with this choice, a bit of information about how certain characteristics of gasoline affect your engine may be of some help. The major factors which make Mogas different from Avgas center around volatility and Octane Rating, Leadis an important, but smaller issue.

Volatility
The volatility is a measure of the fuel's ease of evaporation in the prevailing atmospheric conditions. The volatility of Avgas is kept constant all year, for all geographic locations. The volatility of Mogas is changed to suit both the season, and location of point of sale. A high volatility gasoline will make the engine easier to start, but more likely to vapour lock after it is running. Vapour lock is the boiling, or evaporation, of the gasoline in the fuel system. The fuel vapour is not enough fuel for the engine to run , so it stops, and is very hard to restart until it cools. Automotive consumers of gasoline have, over the years, demanded cars that will start, and keep running, all year around. The gasoline manufacturers responded by creating a system whereby the volatility is changed as appropriate for the climate. When this then created vapour lock problems in some cars, fuel system designs were changed to eliminate that problem. Nearly all cars now have the fuel pump in, or very near the gas tank. This keeps the entire fuel system under considerable pressure, and eliminates vapour lock.
Why not change aircraft fuel systems to this design to eliminate the vapour lock risk? Four reasons: Redesigning, and reworking anything on an airplane is costly and time consuming, and the need, in this case, is great enough. Secondly, for carburetor equipped aircraft, the carb cannot withstand the high fuel system pressure (most carbs are happy from 1 to 5 PSI), which would be required to eliminate vapour lock. Thirdly, for injected aircraft, the engine relies on a pressure fuel system, if we put electric pumps out at the tanks, and have an electrical failure, we are going to loose fuel pressure and have an engine failure. The engine driven fuel pump is an important part of safe flight. Last important reason: Unlike cars, aircraft fuel lines run inside the cabin. If a line or fitting failed, would you want high pressure fuel spraying around the cabin?

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The concerns about the volatility of Mogas as it applies to safe flight, have been well addressed, and very thoroughly tested. You can be sure that as long as you use the gasoline of the season, as directed by the conditions of the STC, you will be as safe as if you were using Avgas. A move toward a cleaner environment ( less fuel vapour in the air from evaporating supplies) will see Mogas volatility being gradually reduced in the years to come. In the mean time: Use gasoline purchased from a reputable supplier during the season in which it was purchased. DO NOT use gasoline purchased in the winter, during the warm spring and summer. Ensure that full power is available early in the takeoff, and if you are still concerned on a really hot day, mix in some 100LL.

Octane

Octane is actually a liquid which can be used as a fuel. If used as a fuel in its pure form, it would have an Octane Rating of exactly 100, and flying would be really expensive! To reduce the cost of flying for us, the gasoline manufacturers blend other much cheaper liquids to create a gasoline which is suitable for use. The anti-knock qualities of this fuel are compared to that of Octane, and a numerical "rating" given. The elements which increase Octane Rating are very expensive (like Octane itself), and are not needlessly added, so you can count on the Octane Rating of the gasoline you buy, being very accurate. Tetra-Ethyl Lead is also used to boost Octane Rating, more on that later.
If the Octane Rating of the gasoline you are using is too low, detonation is a risk.
Detonation is most easily described as ignition of the gasoline vapour prior to spark plug firing. It is only likely to occur at full throttle. Any power setting less than full throttle reduces the factors which promote detonation. The effects of detonation can be anywhere from not detectable, to immediately destructive.
It is well understood that engines run best when the timing of the spark plug firing is actually matched to the ideal position of the piston as it rises in the compression stroke. Too late (lower timing angle), and the engine develops noticeably less power, and is at greater risk of detonation. Too early (higher timing angle), and the engine may develop a bit more power, but it is under much greater strain due to increased cylinder pressures. This can be explained by understanding that though brief, it does take time for the fuel/air mixture to burn in the cylinder. Only after the mixture is completely burned, is the desired explosive pressure achieved. It is very desirable to have this peak explosive pressure occur exactly at the time when the piston is just beginning to go down the power stroke. This is where the power comes from! If this peak pressure occurs too early in the stroke, it actually applies a braking force to the rising piston, robbing power, and then the pressure is depleted when the piston finally reaches the power stroke, again, robbing power.

Page 3
In this regard, both very advanced timing, and detonation can be seen to rob power, and apply excess strain on the engine. Detonation, however, has the added danger of allowing combustion to begin in an area of the combustion chamber which was not designed to withstand it. How can that be, you might ask? Consider that the source of ignition is supposed to be the spark plugs. They are positioned in such a way so as to ensure that the flame front radiates outward evenly. This ball of fire is actually surrounded by a wall of unburned fuel which cools it as it contacts the cylinder and piston. This unburned fuel is there because at full power, with the mixture full rich, there is too much fuel for the oxygen present, and without oxygen the fuel won't burn, so it is just there to cool the combustion chamber. You can lean at lower power settings because you are developing less power so there is less total heat, and cooling is not required. If the flame front begins at a point other than intended, or that cooling rich mixture is not there, very hot flame can impinge on the bare aluminum of the cylinder head or the piston top. Flame temperatures can reach 4000 F, aluminum melts at about 1300 F.
Detonation can only be detected in the cockpit by a loss of power and an indication of high cylinder head temperature, both of which will only be obvious only after the damage has begun. Detonation testing for engine approval is a complicated process which involves deliberately causing the engine to detonate to prove you can detect it, and then testing the subject gasoline to prove that not only does it not detonate, but there is a good margin between normal operating conditions, and those conditions which might result in detonation. The conditions which might promote detonation include: high ambient air temperature, high cylinder head temperature, high power, low engine speed (running a constant speed prop "over square", and low Octane gasoline.
You can eliminate the risk of detonation by keeping you engine running as cool as possible, ensuring that you are using gasoline with an Octane Rating which meets the manufacturer's requirements, and if your engine has a constant speed prop, keeping the RPM high. In normally aspirated engines, there should never be a need to run the Manifold Pressure in inches higher than the RPM in hundreds. When you reduce power, reduce the throttle first, then the prop.

Tetra-Ethyl Lead

"Lead" is used mainly to boost Octane. The effect of the lead in this regard is to reduce the gasoline's likelihood to ignite before the spark hits it. Lead does not increase the power at all, instead, it allows the use of higher compression ratios in engine design, which will give you more power from the same size engine. Tetra-Ethyl Lead has been found to be very bad for our heath, and the environment. This has resulted in it having been banned in all gasolines except Avgas. The lead in Avgas was reduced by half, which resulted in 100LL, but there is still a lot of Lead in 100LL. Like other Octane boosters, Lead is expensive, and is only added if it is needed. 100LL must have Lead to meet the Octane Rating, but 80/87 usually does not need Lead at all. Most of the 80/87 you might have ever purchased, probably did not have any lead at all. Lead is permitted in 80/87 to allow for intermixing with 100/130 during handling and transport. Some manufacturers of 80/87 are reported to have added some Lead at times, but not to the limits allowed.

Page 4
The use of 100LL in engines originally designed for 80/87 is encouraged by the Avgas manufacturers primarily to reduce the demand for 80/87, which they no longer want to manufacture. 100/130 was always an approved alternate fuel for these low compression engines, but never the preferred fuel. 100LL meets the performance requirements for 100/130 so it was substituted. Somewhere along the line, some people forgot that all that Lead really doesn't work well in low compression engines. These engines just don't have the extreme operating temperatures and pressures to burn off lots of lead . The result is often fouled spark plugs, sticking exhaust valves, and sticking piston rings. These problems go from a nuisance, to very costly and unsafe. The use of Mogas has defiantly eliminated these problems for many pilots.
A small amount of Lead has the beneficial effect of providing a protective coating on the exhaust valves. This coating dramatically reduces erosion of the valve face and seat, and the wear of the guide. Aircraft which have operated for hundreds of hours on only Mogas have sometimes been found to have such valve wear. For aircraft which had even small amounts of 100LL at times ( one in twenty fillups), the wear was noticeably reduced. Recent testing with special additives has produced excellent results in regard to eliminating this early valve damage. This additive can be added to the gasoline at any point, is very safe to use, and is added in such small quantities that it does not take the gasoline off specification. Approval of this product is currently underway with Transport Canada, but because the amount used is so small, it will probably be difficult for Transport to disapprove.

In Summary:

For engines originally designed to use 80/87, usually any of the other gasolines will work, but each has drawbacks if used exclusively. Choose a gasoline which is approved for use in your airplane and engine. Regardless of what type it is, ensure that it is handled safely, and protected from contamination. If you choose to use Mogas, buy it from a reputable supplier, and use it during the season in which it was purchased. If you have a larger engine with a constant speed prop, at times when you are at or near full power, avoid power settings with a high manifold pressure and low RPM. If you are operating on a very hot day, take steps to keep the fuel cool: Refuel just before takeoff (in-ground tanks keep the gasoline quite cool), park in the shade. If you have just landed, leave cowl flaps open, and open the oil door on the cowl to let out heat. In all cases, ensure that full power is available early in the takeoff.
You may have noticed that gasoline and oil are among the very few things that you service your plane with, which are not specifically signed off as being airworthy before you fly with them, take the responsibility yourself, because it matters to you.