Rotax 4 stroke carb heat system

[chevvron]

During an incident with a rough running Rotax engine in a Eurostar, it was suggested to the pilot that he try carb heat; pilot replied it was permanently in carb heat.
Is this true for all Rotax 4 stroke/4 cyls? If so it needs to be publicised to all ATSU's

[Rod1]

Complex question. The local UK Rotax distributor has developed an electric heater for the carb’s which can be installed to be always on, or with an on / off switch. This system is fitted to all recent Eurostars and can be retrofitted. Other aircraft, like my MCR 01, have an hot air system as part of the kit and still more do not have any carb heat at all.

Rod1

[funfly]

Rotax have for some time offered a carb heater which is a water jacket around the carb fed, of course, from the cooling water system. This is obviously permanently on, the attraction being that it does not use unfiltered air or affect air flow in any way. My own experience with one fitted was that I never experienced carb ice - but I could have been lucky.
Jabiru, on the other hand, have developed an electric heater which is plugged into the side of the carb and does virtually the same job. In this unit there are two settings (5A & 10A I think) and the unit is generally left on at the lower setting all the time. Jabiru engines are liable to carb icing while ticking over on the ground and when I had one of these fitted to a jabiru engine I, again, had no experience of carb icing.
I understand that the jabiru electrical fitment can be used on other engines, if I had a Rotax engine again I think I would go for the water jacket option as it uses no power etc.

[Genghis the Engineer]

As has been said, there are several systems in use on Rotax 912 engines, the majority of which are always on, and most of the rest are not cockpit controllable (i.e. you can only select it on/off under the cowling).

Given that the pilot will/should/did know this, why on earth should an ATSU need this information - if they are giving aircraft handling advice they should be shot anyhow. (If they happen to be a qualified pilot on type, that's possibly different).

G

[FlyingForFun]

The Rotax 914 in the Europa I used to fly didn't have carb heat - it apparently got all the heat it needed from the turbo-charger, and I certainly didn't experience any carb ice in the time I flew it.

FFF
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[chevvron]

Genghis;
It's useful for ATC to know this.
Many years ago, I witnessed a Cessna 150 student solo; he reported rough running, unable to maintain height, and was setting up for a forced landing. He was obviously EXTREMELY nervous. The controller (who happened to be current on '150's) asked if he had tried carb heat; answer no; he tried it and after the usual delay, the engine regained power! Result; he returned safely to his airfield and there was no 'slightly bent' aircraft in a farmer's field.
THAT'S why it's useful fro ATC to know if you have it. Nuff said?

[Genghis the Engineer]

Sorry, I can't agree.

Your story is an excellent example of the importance of having a competent pilot (ideally an instructor familiar with the type) available particularly when students are airborne solo. [In fact I believe it's legally required isn't it?]

I do not believe that it supports having ATC, who are not pilots, giving piloting advice on RT or being encouraged to do so.

G

[CTAviation]

The Eurostar is fitted with the Skydrive coolant carb heater, this is always on, as it heats the carburettor body and not the intake air it has no effect on engine power.It does however require the coolant to be at a reasonable temperature for it to work efficiently so during the colder months some blanking of the radiator may be required.With some 700+ hours on Eurostars I don't think I have ever experienced any carb ice so I would want to investigate this rough running further (not that I am saying it wasn't carb ice though)

Chris Theakstone

[chevvron]

Genghis;
you obviously don't realise that many ATCO's DO hold current licences; quite a few are also instructors.

CT;
the guy said he thought his carbs had become unbalanced; is this possible after being airborne about 30min?

[CTAviation]

There are lots of possibilities, unless something has come loose on the throttle linkages, or a split carb rubber I doubt it was carb balance especially if it returned to normal (did it?)
Possible fuel starvation on one carb ? main jet blocked ?
was this a factory or homebuilt aircraft ?
Too many times people have blamed carb icing for rough running and not bothered investigating for any other cause only to have it return at a more critical time and bend thier plane. Then again it could as I said have been icing.

Chris

And Gengis, didn\'t you know it is radio waves that keep aircraft in the sky, nothing to do with bernouli ! I once turned the radio off and only just missed the ground in the panic to turn it on and make a call to a FIS fifty miles away for traffic information ! (joke so don\'t all start shouting)

[Genghis the Engineer]

Chris - I have heard that view, or at-least detected it in many pilots, particularly those who fly things a little larger than your usual steed. So far as I can tell, the few hundred hours I've done (including my first solo) without the aid of radio waves went just as well as the flying with a radio, so I'm clearly missing something.

Chevvron - where the ATCO is a pilot that is great. Where they are not, it is NOT appropriate IMHO for them to start telling people who are (even students) how to fly, and they should stick to where and when. If there is a problem where piloting advice is needed, then they should find a competent one (quickly!), not try to wing it on the basis of a limited amount of provided information.

G

N.B. Chris, you should know by now that it's neither Bernoullis nor radio waves that keep you flying - it's an equal and opposite reaction to the lightening of the pilot's pocket contents. The more his wallet lightens, the more lift is generated, that's why helicopters (which are heavy and refuse to fly under normal circumstances) need so much more wallet lightening than smaller lighter flying machines. Also aeroplanes with Rotax engines are inevitably smaller and lighter than those with Lycontinentals, so the same applies.

[Say again s l o w l y]

I must agree with Genghis here. In the case of an emergency, the last thing I would want is for anyone to start giving me hints, whilst I'm busy enough as it is.

Whilst I can imagine it must be very hard to sit there and listen out when you know someone is in trouble, unless you are an instructor or extremely experienced on type, then clam up and let the poor s*d go through the drills they should have had bashed into them.

On the reverse, there are many times I've heard ATC stuff up royally or get flustered and whilst I've been tempted, I'd never dream of actually piping up with some snippet of wisdom(!), especially if someone had just shouted MAYDAY or PAN.

[DFC]

Genghis,

Have a listen to this;

http://www.alexisparkinn.com/photogallery/Videos/flightassist.mp3

What would be wrong is for pilots to rely on ATC to do anything other than ATC or for a pilot to effectively pass their command of the aircraft over to any outside agency. Listening to advice and making a decision is good CRM especially in an emergency.

Regards,

DFC

[Say again s l o w l y]

These guy's are specifically trained to help and did a fantastic job with obviously a very scared and lucky chap.

It wasn't a 'normal' emergency, the pilot panicked and didn't know what to do. His training either wasn't good enough or his decision making was poor. Maybe a combination of both.

If someone is obviously panicking and asks for help, then there is a case for help from outside, but otherwise any interference would be a problem from my point of view by taking the mind off the task inhand at what could be a critical point.

A very sobering clip, I do hope he sent them a case of booze after that, it's the least he could have done.