Oh dear my head hurts !

Why modified olive oil ? Well why not ? There are always more ways than one to skin a cat (no animals were hurt in the making of this respnse ! )

From the testing I have done so far.

Castor needs a high ether content, I have found the hard way, that 25% castor content needs 15% ether content as a minimum. Below that ratio then the castor starts dropping out and forming a deposit. Unless you are prepared to use a goodly amount of ether then castor oil is a problem.

Modified olive oil combined with 10 % ether gives remarkably good and easy starting and also runs well. I find that this mix will idle and throttle O.K once the correct settings are found.

I found that 10% ether and new (not used) car engine oil rsn well in one engine but was not as good in another... however this was a limited test and I need to repeat it to be more conclusive. This mix would idle and throttle O.K when the correct settings were found.

The bulk of my testing was initially done on a "sacrificial "(read spare and unused) engine without an RC carb. Once confidence was gained in the lubrication I moved onto an engine with RC carb.

I know that olive oil and kerosene will run OK but need special starting technique. I don't yet know how that mix will work with an RC throttle.

I know that car engine oil (this brand anyway) with kerosene, once started will run well. I don't know how it will work with an RC carb.

I know that including upto 2.5 % ignition improver is beneficial in all low ether and non-ether fuel mixes.

I found that when using a non-ether mix made up with car engine oil and paraffin plus ignition improver the engine, including the crankcase ran much hotter than usual. i also noted that the exhaust seemed to be "drier" than usual. Despite fiddling with the needle I didn't note much change in the exhaust and it was of a blue'ish colour.

When using modified olive oil I find that there is a lot of oil thrown out with the exhaust, this could well contribute to keeping the engine cooler.

I need to do some more direct comparisons between fuel mixes with modded olive oil as against car engine oil. At the moment I just have a feeling that the car engine oil based fuels are running hotter. TYreven might not be experiencing this as he is using pump diesel instead of kerosene, I reckon the kerosene will burn hotter.

Fuel mixes with both modded olive oil and also those with car engine oil can both result in the compression being backed off more than with conventional high ether fuels. I think contributing factors to this are... increased kerosene content, which leads to hotter combustion, which then leads to lower compression being required. Also the inclusion of ignition improver can make a big difference to compression settings.

I need to do some direct comparisons, over a few engine runs of modded olive oil as opposed to car engine oil.

It may well turn out that ... for good idle and throttling we need some ether content, however tests up to date show that this is probably going to be far less than the amounts normally regarded as necessary...... thus the fuel is cheaper. If we need 10% ether then the gallon of high ether fuel you buy can be diluted to give 3 gallons. Sensible handling will prevent unecessary ether loss.

I do know for a fact that I can run a model diesel engine without an RC carb quite satisfactorily on a non-ether fuel. That means that my non-throttling diesel power pods can be used very cheaply !

Andy is pushing the boundaries with bio fuels and some "exotic" materials. Stewart is happily using modded olive oil and 20% ether, Treven is happily flying his black mix.

I have happily flown a 15% ether - 25% castor mix and that works well. The weather has thwarted flying tests this week.

I am trying to limit my testing to modded olive oil in comparison to car engine oil as lubricant. I want to do some more extensive testing with these two to see if there really is a reason to use one in preference to the other. There will be ignition improver in the mixes as this has proved itself - so far. The only other thing I will alter is the % of ether so I can compare low ether mix with totally non-ether. Trouble is it can take a while... you need a decently long engine run to establish settings and stability. The engine then needs to cool down so that the next test starts from a level playing field.... but it is fun !

Reg