Right.... Todays testing !

Couldn't use my usual spot as there were a couple of cars parked up, the tide was right up so they were probably bird watching - the birds being along the shoreline as their feeding areas were covered until the tide started dropping. Went onto the front side of the island. Waves breaking high up on the shore and quite pleasant

Temperature was a cool 8 degrees C (46F).

ALL fuel mixes used had 2.5 % of an ignition improver added.

3 hours spent testing in total and the engine was given several runs on each mix to get a reliable result and feel for each fuel.

Engine used was a PAW 2.49 with RC carb

First fuel mix.....

10% ether, 30% olive oil, 8% castor the rest kerosene.

Ran well, idled very slowly and steadily for minutes at a time and throttled O.K even from a long idle period....... it was felt that there was a bit of a "burble" when banging the throttle open.
This mix is good and I would happily use it.

Next mix.....

10% ether, 8% castor, 25 % engine oil (new and semi-synthetic) the rest kerosene.

Ran well, idled pretty well, but not as slowly and steadily as the mix with olive oil lube. It throttled well and was felt to just have an edge on the olive oil mix in this respect when the throttle was banged open.

There was no needle setting difference and the compression was exactly the same for the mix with olive oil lube and also the mix with car engine oil lube. There was virtually no difference between the 2 mixes although the mix using olive oil lube definitely idled slower and VERY steadily. I left it on a very slow idle for 4 -5 minutes and it never faltered..... either of these mixes is good but see later....

------------------------------------------------------------------------------------

Non-ether mixes. both with 2.5% ignition improver.

First mix

30% olive oil the rest kerosene.

Ran well, idled O.K and throttled O.K

This mix could be used to fly as it responded well. However it didn't seem quite as smooth as when using a mix with 10% ether. If I was using bigger engines than those I do use I would probably go with this mix on cost grounds alone...... however see later...

Mix 2

25 % new car engine oil semi-synthetic the rest kerosene.

This mix was a problem.... it was difficult to start, compression needed chasing around, the engine was never smooth. I never got to check it's idle and throttle response as it was running "lumpily"
it stopped and I tipped the rest of the fuel out of the tank.... test concluded.

This last may not have been a fair test. When I picked the jar up with this fuel in I noticed it was cloudy. It has beeen in my shed since my last testing and I am wondering if I got the right stuff or if something else has been put in and since forgotten about. I seem to remember a previous test with this mix of ingredients working O.K apart from the engine being rather hot.

-------------------------------------------------------------------------------

Those who have read my previous posts will know that my 10% ether mixes also contain 8% castor as I am diluting down a commercial fuel mix to get the ether content down from 30% to 10%.
The % of olive oil is high at 30% as I am using up the first batch I ever made which had the quantities just measured out for simplicity.... the high oil content of 30% olive oil and 8% castor doesn't give any problems and indeed probably helps engine cooling by limiting the amount of kerosene in the fuel.

Conclusion....

The non-ether mixes are viable as a usable fuel. The car engine oil one was an anomaly as I have tested it before and it was O.K on that occasion. As I mentioned I would probably use these in a bigger engine.... with a possibility that is mentioned below.

The two mixes using 10% ether and either olive oil or car engine oil are both very good and I could quite happily use them, however......

I had a quick think and tipped an equal amount of these two mixes into a jar. So now I had 10% ether and a mix of olive oil, car engine oil and a small % of castor.

Will it.................................. ???????

It certainly did

This concoction ran like a DREAM ! It ran smoothly, it idled with all the slowness and steadiness of the olive oil mix and it had the marginally better response to banging open the throttle that was evident with the car engine oil.

Was it a fluke....? No 'cos I repeated the test with another tank full.

So there we have it.... two mixes using 10% ether which had just barely discernible differences between them - apart from the superior idling when using olive oil. Mixed together and I had a fuel that I don't think could be improved on. The only difference between this fuel and high (30%+) ether content fuel is .... the high ether will start easier. it will run a bit cooler - not a lot of difference though and the cost of the fuel is now reduced to a 1/3 of the cost of the commercial mix.

The engine, including the crankcase were at an acceptable temperature and I didn't have any concerns over the engine running too hot.

The 10% ether fuels ran with about a 1/4 turn less compression than when using a high ether fuel.

The non-ether fuels run about 1/2 turn less compression than when using high ether content fuel.

I don't intend to run a totally etherless fuel as I think the 10% ether is an asset in my 1.49 and 2.49 engines. If I was to consider a non-ether fuel then I would explore the possibility of mixing it with both modified olive oil and car engine oil to see if there was a benefit by using both. That can wait until I get a bigger engine or two !

So there we have it... 3 hours testing and most mixes were run at least twice and some were run three times to check consistency. At the end of it I have a mix that will do anything I want from it and will idle until the tank runs out if left to do so. All engine runs (apart from the aborted one) were of 10 minutes or more duration and varied from idle to throttle banged open, flat out running, 1/2 speed, left at various speeds for minutes at a time and then suddenly varied and all mixes worked (apart from the one).

The 10% ether mix containing modified olive oil, car engine oil and a small amount of castor will suit my purposes very nicely I reckon......

Reg