help with fuel for os91vrdf
 

hi im in australia and not far off having my df f20 ready to go, the problem is which fuel to use? i can get all the raw materials but im hearing that synthetics are the way to go now and not castor!. can i use a standard blend say cool power 5% and just add a bit more oil to make it up to 20%, ive heard that df like 20%+ oil. all the df blends seem to have been forgotten now. maybe df is dead.... are synthetic oils good enough? does anyone have any recipies?
thanks greg
happy flying

RE: help with fuel for os91vrdf
 

You can run up to 25% oil content if you want without hurting the performance or idle. 22-23% oil is however a safe % for these engines. A castor/syntetic blens is better than only synthetics.

RE: help with fuel for os91vrdf
 

flyer95 that is what ive heard also but what is the ratio of synthetic to castor?
thanks greg

RE: help with fuel for os91vrdf
 

Gregor,


If you will be using American made synthetic oils, DON'T use purely synthetics.
Your engine will not have much protection and will die young!

If you have access to Sachs Aerosynth II/III, or Aerosave synthetics, you can risk lowering the percentage of castor oil to 2-3%.
If not, use half castor in a 22-23% total oil for this engine.

Even OS don't recommend all synthetics for their ABN engines, like this VR-DF.

RE: help with fuel for os91vrdf
 

I would mix a blend of 1/2 castor, and 1/2 Klotz with 20% total oil,
or I would run it on straight castor. You couldn't pay me enough
money to run it in straight synthetic oil. [:@]

FBD.

RE: help with fuel for os91vrdf
 

For ducted-fan engines, the oil content should be AT LEAST 22%. 24%-25% is better. Lower oil content fuels will cause the lower end of the connecting rod to seize to the crankshaft. The high RPM of the engine makes it difficult for it to get enough lubrication with lower-oil fuels.

Wildcat Ducted Fan fuels have 23% oil and 5% or 10% nitro. You don't need high-nitro fuels for good ducted-fan operation.

RE: help with fuel for os91vrdf
 

I came across a couple of threads in RCU the other day doing a search on jet oils and it seems that the DF guys like using the jet oils. I've run a couple of sport engines on straight Mobil Jet Oil II and if I had your engine I'd probably go for something like a 50/50 blend of jet oil and castor at about 25% total oil.

RE: help with fuel for os91vrdf
 

Dar Zeelon,

My experiences with Aerosave in high rpm engines have been less than stellar to say the least. It is truly a great lubricant for standard sport two strokes and four stroke engines, but for high rpm, the oil just produces too much drag because it retains its viscosity at high temperatures much better than other oils. This may be a desireable feat in four strokes, but not in a race tuned two stroke.

I haven't tried the latest Aerosynth III yet, but I have heard very good reports of it. Nothing beats first hand experience though.

RE: help with fuel for os91vrdf
 

I use castor/ synthetic in 50/50 ratio and it has worked good for me for many years in all my engines. The synthetic part of this oil package will keep the engine and the tuned pipe clean so you dont have to take it apart for cleaning[sm=thumbup.gif]

RE: help with fuel for os91vrdf
 

hi and thanks for all of your input, i think that a mix of oil is what ill do maybe klotz and castor 50/50 to make up about 22-23% total oil content with about 5% nitro. are there any better oils than the klotz? or is this as good as synthetic oils get.
thanks greg