biggles

Frank , as you are aware the +Ve pressure is developed in the crankcase , and the vapor carrying oil particles undergo a velocity increase in the dip stick riser , then pass through a narrower pipe into the catch tank via the long hose . As the hose is only marginally smaller ID than the connecting pipes at each end ,the change in pressure and velocity is small , and hence the oil vapor is carried over into the tank . With the suggested mod , that same constant mass flow now enters a a larger space , causing a change in both pressure and velocity , giving the vapor time to condense and return to the engine by gravity . A small amount of oil/vapor mixture may still carry over , but will experience an increase in both velocity and pressure , as it passes through the narrower diameter pipe into the catch tank . Hope this helps , but not always an easy concept to grasp ...... Bob

Fluid dynamics . As pipe diameter increases for the same mass flow, the gas pressure and velocity decreases , . ie slows down the oil vapor flow allowing it to 'plate out' on the inside of the pipe and drain back into sump ..... Bob

That's interesting Mike . I think the pipes at both ends are about 10-12 mm . What sort of fittings do you use at each to increase inside dia. to suit 19 mm hose ....... Bob

Russ , it takes some time for the oil to drain back to the sump . Best to leave it for at least 30 mins to get an accurate dip. As FH says forget about 'recycling ' oil blown out . Fill to level you are comfortable with . You know your aircraft . Personally I am not comfortable with running low on the stick , I tend to use a bit so fill a little higher (at least halfway between L and H ), if it gets blown out then so be it , oil is cheap . I get the impression you tend to operate this way also , which is good considering the country you transit ........ Bob

Our dazza can spell , can't you mate ! ........ Bob.

Someone been giving you a hard time mate ? ....... Bob

I promise not to tell him about those 4.5 metre river dwellers you've got up there Frank ......... Bob

Yeah Frank , but did you see the lean on some of those towers behind the boats Bob

Does seem a little excessive , I'm guessing maybe 150 ml/hr . Any work/alterations done on the engine since 2001 and have you had a leakdown test done recently ....... Bob

Of course there are many types of isolators ranging from $5 as jetjr says , to many hundreds of dollars for the more sophisticated ones , which may also be electrically operated and contain inbuilt electrical protection but are basically the same thing ,however I believe that here we are talking about those manually operated , and in the lower price range . High current carrying leads should be no longer than necessary , well restrained and maintained along with clean and tight connections . Introducing longer leads into the cabin just to mount a cheap switch seems to be counterproductive , as well as introducing another potential point of failure which as pilots we don't need . In the case of an engine fire ,which is the reason some give for fitting an isolator in the first place , it would be far better to follow the instructions in the POH for dealing with the fire .... ie. Increasing speed to Vne and look for a safe area to get the aircraft on the ground asap. Any in flight fire is more likely to be oil/fuel related rather than electrical , hence opening the isolator is likely to be a waste of time anyway . Opening the battery isolator would also cause loss of all instrumentation . Not a good idea when when your aircraft is at or near Vne , unless your glass panel or whatever has a reliable battery back-up . Some also seem to rely on these isolators for safety even when working on or around an engine . Would you replace a car engine drive belt , relying on some cheap device that may have faulty internals . The only safe isolation when working on any engine is to remove A lead from the battery, that way you can actually see the physical break and know you are safe . Don't trust cheap aftermarket parts . Your best insurance against that very rare occurrence of a jammed solenoid is to ensure that is clean and the cables are tightly secured . If in any doubt , replace it with one recommended by the aircraft manufacturer . Finally , if these isolators were considered a necessary safety item then wouldn't our regulator mandate their installation , maybe we should also ask why aircraft manufacturers do not fit them as standard equipment ...... Bob

Sorry Gandalph but I have to disagree with you . I'm not denying that isolators are mandatory in racing cars , but they are not designed for breaking a fault current . Solenoid contacts are electrically operated , operate in milliseconds and are equipped to deal with high currents flows . Being enclosed ,or sealed and devoid of oxygen , they are also unlikely to support combustion . Breaking a fault current with an isolator is a slow manual affair . A bit like pulling the plug on a toaster without switching off first . Good luck ! .... Bob

If the starter solenoid is jammed with the motor drawing full load current, or near to FLC , opening the manual isolator will draw an arc and , if in close proximity to flammable material , will cause a fire ...... Bob

Isolators or whatever you like to call them are just that, an ' isolator ' and not designed to break load current . If used to break the current of a jammed solenoid it may well in fact start a fire . Frank is correct ... Check that the starter has disengaged before moving off .... Bob

Oh give him a break SQ , you'll make him want to go back to work

Now dazz , just because you're back in civilisation for 10 days , don't give us all a hard time ! ..... Bob

Yeah , but that was only one day Dutch . Tell us about some of the good ones . Don't suppose you'll be doing Mel/Singapore next Wednesday by any chance . Bob

Surely nobody would use cruise control in heavy traffic . I have noticed on my inbuilt fuel flow monitor ,that accelerating from 40 to 100 using cruise control (with set point at 100 ), to be far more economical than operating manually , as one would expect with the fuel management systems fitted to modern vehicles . As I used to say to fellow engineers .... " Second class auto is always better than first class manual "....... Bob

Agree with all that Red and have seen it occur many times . Let the idiots do what they like , they'll eventually get caught . Just make sure you do the right thing

The speed limit is the maximum speed allowed . " A revenue raiser " .... Try telling that to a cop that has just attended a multiple fatal involving kids , caused by a speeding driver.... Bob

Hi Lindy Lou , All pretty upbeat for Jab . Aircraft and engines selling well ....... Bob

Yes that can be a problem, as the speed does tend to gather on long downhill stretches, but you can set the control a few km's lower . Of course I was talking about a clear section of level road ...... Bob

I always use cruise control, ' takes the worry out of being close ' ...... Bob

Mmm, " Skycatcher "

For N/S runway . Why quarantine more airspace than necessary ? Bob

Teck our pastime is inherently risky but we , all of us without exception , need to better manage that risk . What may first appear to be just " a few quick circuits "or " a short flight to a nearby airstrip" may turn out not to be the case , due to unforeseen circumstances . We need to display professionalism the moment we board the aircraft until it is back in the hangar . We should all be striving to improve our professionalism as pilots by reviewing our training notes and textbooks, asking for assistance if needed and remember ...... "A good pilot is always learning "