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OEI landing DA42

Peter wrote:

One wonders how much of this is “out there”.

My problem was that my guy couldn’t come with me when I went to pick up the plane. Otherwise, such things would’ve been noticed immediately. That’s why I always recommend professional pre-buy check to everybody. I would be better to stick to that rule as well

LDZA LDVA, Croatia

OTOH, given that the plane isn’t too old, couldn’t it be that this is how the aircraft come out of the factory?

Mainz (EDFZ) & Egelsbach (EDFE), Germany

There have been a number of problems over the years with the quality and fit of various ancillaries on the 1.7 engines. Short hoses, jubilee clips under tension etc all led to a number of avoidable failures.

Most of these issues were swept-up when owners had 2.0 engines fitted. A quick scan of the photos tells me that the engines were not fitted with undying love.

Fly safely
Various UK. Operate throughout Europe and Middle East, United Kingdom

boscomantico wrote:

OTOH, given that the plane isn’t too old, couldn’t it be that this is how the aircraft come out of the factory?

I don’t think so because some hoses have been changed …

LDZA LDVA, Croatia

I’ve certainly had new, factory sourced hoses replaced as they were too short.

Fly safely
Various UK. Operate throughout Europe and Middle East, United Kingdom

Shorrick_Mk2 wrote:

I wouldn’t rate liquid cooling as “complex” in this day and age. Especially considering the very tangible benefits such as continuous max power versus continuous max power for one minute before the engine detonates or overheats.

Think about it: Water pump, thermostat, radiator, and liquid running through literally hundreds of hoses, connectors, engine parts with joints, etc., etc.

Compared to a simple cowl opening and some baffles for strictly air-cooled…. but then again the liquid cooled system has these too !

Thousands of additional failure points and it only takes ONE to shut down the engine.

ps: The Wright Flyer was water-cooled,that was 1903. There is a (thousand) REASON(s) why water cooling was largely abandoned in light GA 100 years ago ..

http://airandspace.si.edu/exhibitions/wright-brothers/online/fly/1903/engine.cfm

Last Edited by Michael at 12 Jun 06:37
FAA A&P/IA
LFPN

All very true Michael, but although I don’t have an engineering background I still suspect “hundreds of hoses” might be hyperbole. I have a numbers background and all i notice is in spite of that added complexity air-cooled engines have an in-flight shutdown rate three times higher than that of the modern liquid cooled engines. Even when used in adverse conditions (say during armed confrontations) 1940’es technology vintage liquid cooled engines have performed at least as well in terms of reliability if not better than the air-cooled counterpart.

This without even accounting for the fact that unlike modern liquid-cooled IFSDs that are uploaded to the manufacturer when the plane gets in maintenance, air-cooled IFSDs are reported on a voluntary basis and might in fact be much higher… it’s probably time to move on and realise that much of the “knowledge” about engines (such as “the engine failed because it was operated LOP” without any actual logging of how the engine was operated) isn’t as good as we once thought it was. Nothing wrong with that. Have there been nagging failures in the early days of modern liquid cooled conversions? Surely – and surely not a lot more than there have been in the early days of air-cooled engines.

Clinging to old tech and old wives tales and accepting that it’s normal for say an AEIO-360 to vapor lock when in inverted flight regimes is counterproductive and in my opinion it’s what it has brought GA in the deep rut it is in today.

Of course Michael is right, what isn’t there can’t break and what is there will eventually break.

However, our air cooled Lycontosaurus engines already have a large number of oil hoses, fittings, etc. The more add on things like constant speed prop, turbo chargers, suction pumps, the more oil hoses going around. Those hoses are often of poor quality and their attachments even worse. There is only one oil pump by the way.

Therefore the water cooling plumbing doesn’t really change much. As part of my pre-flight on longer/more demanding trips, I remove all cowlings and check all hoses. I’m lucky that my airplane can be fully opened in 1 minute with a few camlocks, knowing that there are other models where there is almost no access (TB20 comes to mind).

In my experience with engine failures (and I have too much experience there), an open liquid circuit is one of the main reasons for engine failures.

achimha wrote:

In my experience with engine failures (and I have too much experience there), an open liquid circuit is one of the main reasons for engine failures.

Exactly ! So with liquid cooled you now have effectively DOUBLED your chances of failure on each and every flight.

FAA A&P/IA
LFPN

achimha wrote:

there is almost no access (TB20 comes to mind).

You ought to buy one and then you will see. One can inspect much of the hoses from underneath, by shining a lamp up the air exhaust holes at the bottom. I do that on every preflight. Do you remove all the covers on every preflight?

Few planes (no modern ones, AFAIK) have all the engine covers fully removable, and those I have flown that have, tend to have shagged fittings.

Regarding water cooling, the issue I see is that the mfgs don’t want to spend money on high quality fittings and hoses. On an aircraft, I would use nothing less than steel (stainless, for water coolant) fittings and PTFE hoses which are braided and fireproofed. At around €50-100 each, such hoses are a complete no-brainer, and I cannot understand who so many planes (especially non-certified ones) don’t use them everywhere. Then you need to have proper strain reliefs / hose mounts which stop them flopping about – this is another neglected area.

The reason why loss of coolant is a major item on cars (my Toyota Celica had only one stoppage in the 15 years I had it from new – exactly this) is because they use crap hoses for the water.

However, in Emir’s case, it was down to monkey maintenance, and this brings me back to what I keep saying about the owner having to get “stuck in”, but I get criticised for suggesting that there are bad maintenance companies out there. The reality is that anybody who has a “mechanical/technical brain” (and Emir certainly has) can inspect the work done. Yes… I know about airfield politics, and sometimes this is a problem if the only maint company you have doesn’t want you inspecting their work.

And doing, or being involved in, the 50hr checks is a priceless bonus because you get to know what your plane should look like under the covers – at a cost of a few hours of your time every few months.

Those without a technical aptitude, or those who want to treat their plane like a BMW/Merc/whatever will always be exposed to these issues and they have no choice. That’s GA for you

Administrator
Shoreham EGKA, United Kingdom
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