Weightshift / Trike writeoff - no injury.

[Phil Perry]

Today ( Sun 6th Sept ) at 13:45 local UK time.

 

Aircraft departed rwy 29 at Otherton - engine failed whilst the aircraft was climbing straight ahead ( 290 Deg) and at a height of approx 150 feet.

 

31 year old Restricted Pilot, (49 Hrs total ) "Restricted" = not allowed to exceed 8 NM from rigging point until NAV exams and cross country flights completed .

 

Pilot descended gently into the 18 Kt headwind, and turned left slightly, to avoid the M6 Motorway, coming to rest at an estimated forward speed of approx 30 Mph into a deep ploughed potato crop, where the trike contacted the ground rear wheels first, and then pitched over, severely damaging the trike pod and pylon, wing main keel and leading edge tubes.

 

The pilot was able to exit the wreckage unaided and was not injured in any way.

 

The aircraft was a fairly elderly Pegasus XL-R , powered by an inverted Rotax 447 2 cylinder inline air cooled 2 stroke engine.

 

The engine was examined today by our local engineer who said that in his opinion it had hot seized solid due to no fuel lubrication. The Pilot admitted that it was possible that he had mistaken a Pre-Oiled jerrycan in the boot of his car, for one which had no oil added to the unleaded fuel.

 

In our early years of buying fuel from highway service stations, many of us adopted a simple idea of adding the oil first, before filling at the pump, then clipping a green tag to cans which had oil added, so that this kind of problem would not occur.

 

(An added advantage of this was that as your car bumped along the roads and lanes to the Airfield,. . .the fuel would get a good shake 'N' Mix in the jerrycans ! )

 

But since the advent of mostly four stroke engined flying beasties, . . this idea had obviously faded into obscurity. . . . . .

 

Anyhow,. . .Nobody got dedded this time. . .so it has to be a reasonably good outcome.

 

( Not only this, but if the poor bloke has not got the trike fully Hull insured [ Doubtful due to it's age ] . . then I MIGHT just have a victim,. . .er. . . potential buyer for MY Flash 2 503 trike,. . .which I shall regrettably never fly again, as at my age I really DO prefer flying appliances having integral cabin heating systems. . . . . )

 

Phil

 

 

[facthunter]

You really DO HAVE to know the fuel has oil in it, and it has to be shaken up thoroughly. Nev

 

 

[fly_tornado]

here's a manfred mann, get on the old dog and bone and rabbit and bone old mate into having a captian cook at it

 

 

[Phil Perry]

here's a manfred mann, get on the old dog and bone and rabbit and bone old mate into having a captian cook at it

If you could translate that into Lithuanian slang,. . . we might be onto a winner there FT. . . ( but PLEASE. . . NOT Lithuanian Morse Code thanks. . . )

 

 

[Phil Perry]

You really DO HAVE to know the fuel has oil in it, and it has to be shaken up thoroughly. Nev

OOOOOOOOH Yes.

 

I've made many mistakes over the years that I have been involved with two stroke aircraft engines, but that is NOT one of them. . .If I was ever in ANY doubt about the fuel / oil mixture in the can. . the lot went into the old car or the airfield grass cutting machine, no ifs or buts.. . .and start again. Phil.

 

 

[Soleair]

The ARV Super2 was the first British aircraft to use a 2 stroke engine and gain BCAR Section K 'public transport' certification.

 

The Hewland AE75 engine required premix fuel, & this question of how to ensure oil - or at least enough oil - was present in the fuel had to be discussed with CAA and a solution agreed.

 

That solution was twofold. Firstly, our CEO Richard Noble persuaded Castrol to add a very intense blue dye to the A545 oil we had used for the engine certification running. (This oil was then renamed Castrol Aviation A545 and featured an illustration of the Super2 on the label!) We then produced a colour card which lived in the map pocket of the Super2. The POH stated that prior to operation a fuel sample be taken and after checking for water the colour of the sample was eyeballed against the colour chart. It was possible to get quite an accurate indication of the amount of oil in the mix matching against one of the 4 or 5 colour strips shown in this way.

 

The second step was assessing how little oil was needed for the engine to run without seizing. After completing the many hours of test running required for certification, we gradually reduced the oil input on the test engine, until it got to vanishingly small amounts. In the end, we tried filling the 11 gal tank with neat petrol, the only oil being the normal mix forming the 'unusable' quantity in the tank (about 1/4 gal as I recall). The engine still ran without seizing, at which point we submitted our reports and gained certification from CAA. The engine was only cleared to run on Aviation A545 oil.

 

So while it goes without saying that discipline in ensuring oil is present in premix is essential, it helps to have a procedure & means established to make this as idiot proof as possible.

 

Bruce

 

 

[facthunter]

The dye is a good idea. Some oils have it. I could tell you about two strokes surviving on miniscule amounts of oil but I'm not going to recommend it as a practice. 50:1 is little enough and i usually go about 35:1 Most of it just goes through the engine as there is no retention or recirculation in most engines. The engine is much more stable when hot as the fuel evaporates better, leaving more concentrated oil. One test you can perform is to allow a quantity of fuel onto your hand and as some of it evaporates , you can feel the oiliness. Works better with avgas but only tells you there is some oil, not the mount.

 

The safest is to mix shake and put into tank, or have some specified system but no system is foolproof. If it is done in bulk it may settle to some extent if not agitated. I even shake oils in drums before I remove any if they sit for long, just to be sure it's even. Nev

 

 

[Soleair]

50:1 is little enough and i usually go about 35:1

Please do not do this, nor recommend it to others. I know intuitively you think you are helping the engine lubrication by giving it a bit of extra oil, but you are in fact harming it. At best you are simply wasting money, & at worst shortening the life of the engine with this practice.

 

The manufacturer will determine the precise amount of oil required for his particular engine, & often state to which type of oil this applies (usually mineral, semi or fully synthetic). For example some manufacturers specify 50:1 or 100:1 if using Blue Max. At ARV we specified 50:1 Aviation A545, and to use a different ratio would be operating outside of the certified parameters for this engine.

 

Now if the manufacturer after exhaustive testing has specified the correct ratio of oil, it would be very unwise to assume superior knowledge and decide on your own quantities based on no more than a gut feeling that you are helping the engine lubrication.

 

The first reason not to add excess oil is that this will quite literally 'gum up the works'. Carbon from the excess oil burn will cause the piston rings to stick, reducing power and increasing bore wear. It will also gunk up the exhaust over time. And it's not good for the environment pumping out all that oily blue smoke!

 

The second reason is that excess oil will cause the engine to run lean. This is due again to a couple of effects. The oil in the mix displaces its own volume of petrol, and although it will burn it does not have the calorific value of petrol, so you are effectively weakening the mixture.

 

The other reason is that an oil rich mix will increase the viscosity of the fuel mist seen at the jets. If the jets are sized for a certain 'thickness' of fuel/oil mix, they will not pass the same quantity of 'thicker' mix, although the combustion air intake remains the same. Again, this will lead to a weak mixture with potential for overheating which will certainly shorten the life of the engine and possibly lead to a catastrophic failure.

 

So it really is no help and potentially harmful to add that little bit extra of oil.

 

Bruce

 

 

[facthunter]

I don't go above the maker's recommendations. You coverage is correct. You will change the mixture. It's more important to warm the motor before giving it full chat and not gliding on idle for long periods, unless you have the later engines with pumps. I prefer pre mix by the way. and it's a good thing to run the carb dry with that set-up as residual oil left in the carb blocks it when the fuel evaporates. How reliable your 2 stroke is, is very much up to how well you treat it. Nev