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AAIB report •Jab EFATO UK April '23


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Any rubber shock absorber will deteriorate with use. Maybe number of starts and stops would have an effect.  Also is it neoprene or rubber predominantly?  Rubber is affected by petrol and mineral oil.     Nev

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On the xair it's easy to check the carb sockets each preflight. I always have a look at it , but as you can see there is no support apart from the rubber socket.IMG20240706114821.thumb.jpg.70ce0206def3e360fc3b248450d2f679.jpg

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34 minutes ago, Thruster88 said:

Like a Thruster, you can keep an eye on the engine as you fly.

yes. easy to maintain and inspect. can't beat rag and tube for buzzing around the local area.

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It strikes me, that those of us who discuss engineering systems, all have some concept of "perfection" (don't take me too literally). Where perfection is wanting, we call that poor engineering (or worse).

 

Over many years of tinkering, I have come to realise that what might, at first glance, be categorised as poor engineering (rubber socket/inlet manifold to carburettor) just seem to work despite the naysayers.

 

Rotax carburettors are actually supported, at least in part, by another engineering oddity, a spring.  At least this is compatible with the vibration reducing rubber - it just doesn't look quite adequate and is in an odd location - again it just works.😈

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8 hours ago, danny_galaga said:

What sort of rego was it under? I don't suppose we'd see ANY kind of report if this happened in Australia...

UK permit to fly, which allows the great majority of maintenance to be carried out by the owner, with some work (eg on the control system) needing to be signed for by a competent second person and some work like modifications needing approval by the overseeing organisation (BMAA, LAA) and sign off by an inspector

 

Edited by Red
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5 hours ago, skippydiesel said:

It strikes me, that those of us who discuss engineering systems, all have some concept of "perfection" (don't take me too literally). Where perfection is wanting, we call that poor engineering (or worse).

 

Over many years of tinkering, I have come to realise that what might, at first glance, be categorised as poor engineering (rubber socket/inlet manifold to carburettor) just seem to work despite the naysayers.

 

Rotax carburettors are actually supported, at least in part, by another engineering oddity, a spring.  At least this is compatible with the vibration reducing rubber - it just doesn't look quite adequate and is in an odd location - again it just works.😈

As I've mentioned  in my experience  it just works for a less than adequate time period.

If you look at the installation manual, Rotax actually states fitment should include  a supporting airbox, the omission of such in many uncertified aircraft is done for a variety of reasons, mainly space and weight constraints

 

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Skip,You get "thing" when people don't respond to your questions and then dismiss their contributions when the do.. It JUST works. is a poor  analysis. Try giving that answer in an engineering context, It's failure Mode should also be TAKEN into  account also. Essentially failure of the Powerplant without much warning.  Might as well be a broken major component as far as the effect on continued flight iis.  Simply LABELLING some as "NAYSAYERS" is  BS and insulting. .. Nev

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1 hour ago, Red said:

As I've mentioned  in my experience  it just works for a less than adequate time period.

If you look at the installation manual, Rotax actually states fitment should include  a supporting airbox, the omission of such in many uncertified aircraft is done for a variety of reasons, mainly space and weight constraints

 

What is the "time period" you refer to?  -  less than 5 years, 5 years, more than 5 years?

 

"Rotax actually states fitment should include  a supporting airbox" - Take your word for it but I would point out they also support the minimalist individual conical filters (part number  825551) that are almost ubiquitous, in this part of the World.

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Thet only keep out grasshoppers and large rocks anyhow. You can see through them from one side to the other.  Where's your engine anti Icing? Nev

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54 minutes ago, facthunter said:

Thet only keep out grasshoppers and large rocks anyhow. You can see through them from one side to the other.  Where's your engine anti Icing? Nev

9 series don't suffer from icing much because the carbs are on top where the warm air is.

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1 minute ago, BrendAn said:

9 series don't suffer from icing much because the carbs are on top where the warm air is.

a tecnam i did lessons in would ice up a bit when 1st started but clear as soon as the engine temp started to rise.

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1 hour ago, facthunter said:

Thet only keep out grasshoppers and large rocks anyhow. You can see through them from one side to the other.  Where's your engine anti Icing? Nev

A lot of 912s, including mine have a water jacket around the throat. Initially I was still in 'carb heat ' mind set thinking that's a waste of power because it's always on. But there is virtually no difference in power because all it is doing is keeping the throat surface warm, preventing icing. Great idea, after all that's the bit you don't want iced up, not the air/fuel mix.

 

Note, there is also an electrical version.

Edited by danny_galaga
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14 hours ago, danny_galaga said:

A lot of 912s, including mine have a water jacket around the throat. Initially I was still in 'carb heat ' mind set thinking that's a waste of power because it's always on. But there is virtually no difference in power because all it is doing is keeping the throat surface warm, preventing icing. Great idea, after all that's the bit you don't want iced up, not the air/fuel mix.

 

Note, there is also an electrical version.

i have only been involved with 6 912s and none of them had the heating options.  my jabiru engine has an electric thing on it but i don't know if it helps much.

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Of course you can add a turbo (914) no need for carb heat because the compression of the intake air ( boost) increases the temp.

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Not used on descent. . Icing is still catching people.  Alcohol spray plus heat is used on P&W R 2000. with supercharger.   Nev

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5 hours ago, facthunter said:

Not used on descent. . Icing is still catching people.  Alcohol spray plus heat is used on P&W R 2000. with supercharger.   Nev

Rotax deem heat is not required on their turbocharged engines.

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I don't see anything wrong with CT9000's use of the word "deem", it means "to form or have an opinion, (to) judge, or (to) think".

 

WWW.DICTIONARY.COM

The world's leading online dictionary: English definitions, synonyms, word origins, example sentences, word games, and more. A trusted authority for 25+ years!

 

 

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On 10/07/2024 at 12:24 AM, BrendAn said:

On the xair it's easy to check the carb sockets each preflight. I always have a look at it , but as you can see there is no support apart from the rubber socket.IMG20240706114821.thumb.jpg.70ce0206def3e360fc3b248450d2f679.jpg

Brendan, what is that black round thing with a rod or tube sticking out of its centre that appears to be directly behind the air filter element?

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