Carb Icing - Possible solution

[Head Turner]

In the GASCo magazine this month (Dec 04) is the 'possible' answer to pilots forgetting to adjust Carb Heat.
An inventor has come up with what seems to be the right defence against carb icing. What is even more interesting is the simplicity of the design, one has to wonder why the carburettor manufacturers had not grasp this idea way back. Well it could be that they did but it would have meant a more expensive item and that's something that is important.
What I liked about this is that it would be possible and practicable to warm the carb with engine oil and this hot oil could be fed to the carb, at and below the critical card icing temperature envelope.
Is this not a wonderful flight safety item?
Would it not save a few enforced engine off landings which end in expensive insurance claim?

[CRAN]

Head Turner,

I totally agree.

I believe the microlight people have been using heater coils for similar purposes for many years...maybe Ghengis can point us to a supplier/manufacturer?

CRAN
:ok:

[Genghis the Engineer]

http://www.skydrive.co.uk/sd_sa_ch.asp

http://www.jabiru.co.uk/IceEliminator.htm

Nothing all that new about it, I've been flying with an electric version on an older Rotax engine for years.

All it takes is for somebody to bite the bullet and get an STC to fit (presumably the electric version) onto CofA aeroplanes.

G

[CRAN]

Cheers G

CRAN
:ok:

[Head Turner]

And helicopters - especially the Robbo which seems to be a good machine spoilt by a 'pennyworth of tar' or the lack of it.

[muffin]

I also have been using the Skydrive version on the Rotax 912 in my Zenair for some time. Works brilliantly to the extent that you can completely forget about carb ice. I used to have the problem occasionally before fitting it, but never since.

[Head Turner]

So my question now is 'Why is this carb warmer not a standard fit to Robbos'?

I use the R22 as an example as this is the most popular helicopter which suffers from accidents caused by carb icing.

So Why?

[Helinut]

Probably because of where they live RHC don't seem to be sensitive about carb icing - the same probably applies to the other piston hele makers. Anyone operating piston/carb heles in temperate climes has a different view. It is always difficult to make financial sense of anything to do with heles, but a mod to retrofit these sort of systems to these heles has to be a good idea.

One of the paradoxes of our safety regulation system is that it inhibits developments that would improve safety, because of the enormous cost of the process and the small market from which to recover the regulatory costs.

[Head Turner]

I take Helinuts point regarding the paradoxes of our safety regulation process to actually mean that there are those who could change this system but it's just too difficult and time consuming and etc.
But surely it must be the same system as building and having items such as floats/hooks/bambi buckets/engine fire extinguishing kits/air conditioning/loud speakers/Nightsun searchlights etc certificated and those are not fitted to every helicopter, just there when and where required.

As is so often the case there are those who strive so hard to make things safer, and governmental departments are established that are funded to provide buildings to house those workers who are employed to enhance safety, but they are useless because a system thwarts their purpose.

A really crazy world.

To come back to earth of course there are fuel injected engines that would equally solve the carb icing dangers to life. Training organisations should therefore avoid using helicopters which are prone to carb icing as a flight safety measure.

[Banjo]

There is another reason for Robinson not fitting anything to help prevent carb icing. In fact it is the same reason that can prevent a lot of improvments being made and that is litigation.

As soon as Frank puts something on his aircraft to improve it out come the lawyers with lawsuits claiming that there must have been something wrong for him to fix it therefore he is liable for the death of X,Y and Z. A sad situation where it is better from a companies point of view to leave certain faults on their aircraft than to fix them. Robinson and the aviation industry are not the only people to have discovered this. Still keeps the been counters in work.

[muffin]

Also the engine in the R22 is air cooled so there is no coolant to pipe round the carb body. I guess you could do it with hot oil though?

[Genghis the Engineer]

Or electrickery - that's normal with the Rotax air cooled 2-strokes, just need a bigger one. Had this on a 40hp single carb engine on a microlight, the RPM needle just about flickered down from 3,000 at idle when you turned carb heat on - or in other words the power loss was trivial.

http://www.onlyinternet.net/ldavis/carbheat.jpg
(It's the bit between the carb body and the air filter - about $300 a pair from Aircraft Spruce I believe).

Needless to say, I never saw any icing with this.

G

[Helinut]

muffin,

As I recall, the R22 inlet manifold does pass through the oil sump, and therefore does derive some heating from the oil (when it is warm).

When I used to do training on the R22, it was very noticeable during the wet winter that first cold start of the day often exhibited carb icing signs when the carb heat was checked during start-up. I always used to be very careful not to do practice autos or even quick stops until the engine was really warmed through.