I read about this in the USA.
Many think that a 25hr oil change interval is much better than 50hr.
And I am sure the oil filter is good for 50 or, on an SR22, 100hrs?
There are various products on the market which can pump it out. Some are really cheap; this is a heavy duty one
Obviously one is depriving oneself of the opportunity to examine the filter and the strainer, and eyeballing the engine generally, but it would save removing the cowlings (and the prop spinner) just to reach the drail plug. And on the TB20 the oil filter can be easily done from the top cowling only.
It would also be a bonus for anyone whose airfield politics prevent them from doing any work on the plane. The required conditions (25m vis in fog 
) are not often present.
At first thought: no relation between the frequency of oil change and the equipment used – unless you imply it would be less of a hassle with such a device, so one would be less reluctant?
Much depends on the complexity of the engine and its procedures – on my Rotax an oil change is a non-event, the worst point is to not forget the copper ring on the drain bolt. And removing the complete cowl ought to be done before every flight anyway (I must admit to having been slightly negligent, though, in this corner). So I do not see the advantage, almost the contrary. You do want to take a good look around the engine every so often, anyway, don’t you?
Also I wonder how one can be sure the suction tube has reached the bottom of the oil reservoir, except by metering the oil removed.
As for the fog requirement: the UK must surely have some WW2 fog generators available from army stocks? ;)
That was a bad idea for cars when it first came up, and I am sure it is a bad idea for planes too. It is much better to drain the hot oil together with all the stuff that’s in the sump … and not suck out the oil and leave most of the dirt etc. in the sump. I would never use it.
When you have a drainable sump, this is what you use. An oil suction pump is used when you cannot drain the sump. Boat engines are typical examples. You would never do this when there are other options.
A cheap manual oil suction pump does the job equally well, even in daily professional use.
We use them all the time in my business (cars). When I first bought one many years ago I experimented by removing the sump plug after vacuum draining and I can happily report that 99% of the oil had successfully been evacuated.
However, I wouldn’t do it on my aeroplane because taking the cowl off and having a good look around is never a bad thing.
Assuming one could get access to push some sort of tube to the bottom of the sump, there would be no difficulty sucking up the crap from the very bottom. It would be no worse than draining the oil out conventionally; you still only shift the stuff that’s next to the drain point.
This is why when taking an oil sample for analysis, you get the engine warm (necessary anyway else the oil takes ages to drain) and time say 1 minute from the moment of opening to the moment the sample is taken.
I too agree that the inspection opportunity is not to be wasted, but as I mentioned there can be times when one needs to change the oil but cannot do it without flying somewhere where it can be done without political issues. Inevitably you need a helpful contact at this other location – you cannot just fly to Airport X and start taking the cowlings off there
I doubt that you can get all the dirt out with the suction pump, but maybe it works, it might be an OWT. I have heard though, from experienced car mechanics, that the new oil looks black much sooner after it was changed using a pump.
Peter wrote:
but it would save removing the cowlings (and the prop spinner) just to reach the drail plug
That’s one nice thing about having an ancient plane: the cowls all open up, and you don’t have to remove anything to get at the oil quick drain.
I never liked the cowlings where all you get is a little oil inspection door, you can’t really do a very good preflight inspection of the engine (I’ve caught a couple of exhaust leaks just because I can open the cowling easily) and it makes routine maintenance that much more timeconsuming.
Flyer59 wrote:
That was a bad idea for cars when it first came up, and I am sure it is a bad idea for planes too. It is much better to drain the hot oil together with all the stuff that’s in the sump … and not suck out the oil and leave most of the dirt etc. in the sump. I would never use it.
Exactly! Use a Quick Drain from Safair or similar and a hose. Draining the warm oild takes a mere 10 minutes.
Pay $ 144 for a machine that will eventually stop working when gravity will do the job for ever reliably and for free ? ……….. I don’t think so !!!
