Carbon Fibre Propeller Damage by Heat??

[Disco]

Guys.

How much heat would it take to damage a carbon fibre propeller?  How hot does an autoflight EJ200 gearbox fitted to a EJ25 get?  How much heat is transfered to the prop hub from the gearbox?   Is it enough to damage a carbon fibre propeller or seperate the carbon fibre from the aluminium at the root of the prop?  If the propeller is reattached to the aluminium so it doesnt' change pitch, could the blades be too brittle to be safe for use?   Is it a better idea to use a different material for a propeller instead of carbon fibre?


Any info would be great.

Dean

[SamL]

What have you done Disco

[Baz]

Call Rob I bet he'll know

[Bones]

Damn i thought i asked some round about questions

[Graeme Monro]

Damn i thought i asked some round about questions

Yep you do, in a round about sort of way.

Graeme.

[tonydenton]

dean , order another set of blades from rob and move your exhaust out let. probably your seals in your gearbox would leak first letting you know that it had been heat effected.

[Chopper Reid]

The turbo on my old engine used to blow straight out onto the prop and I'm not sure how many hours without looking at the book this took place for but no problems were experienced with the Warp Drive prop.[ Aprox over 2000 hours.] Mongrel engine though !! I'm very pleased to have gotten rid of that excuse for an engine.

[Waddles]

Gents,

An Airworthiness Alert (AA) has been issued in response to an incident report on this subject.

The facts stated in the AA have been confirmed by the prop manufacturer, another Australian prop manufacturer, Jabiru aircraft and a composites expert from the boat building industry.

Exhaust heat is not the only source of heat that will cause problems with composites and dark colours on composite structures are the worst culprits.

Exhaust heat also affects fixed wing aircraft like the Quik EZE family and this was with wooden props that delaminated attritutable to exhaust heat.

Guess my black Raftor is in trouble.

Waddles.

[Chopper Reid]

After seeing where the exhaust hits the prop, I'm not at all surprised to hear that damage has been done. On my old turbo set up, it hit the prop some third to half way along and then at an angle so the passing air would dissipate some of the blast but even this left a mark that you could see on the prop.

Once again, throw the turbo away and if anyone loves turbos that much, buy a 914 !

[Bones]

After seeing where the exhaust hits the prop, I'm not at all surprised to hear that damage has been done. On my old turbo set up, it hit the prop some third to half way along and then at an angle so the passing air would dissipate some of the blast but even this left a mark that you could see on the prop.

Once again, throw the turbo away and if anyone loves turbos that much, buy a 914 !

Actually Brain, i challege you on that thought,  the turbo ACTUALLY takes heat out of the exhaust gasses, it needs to do this to generate the power to pump air for the motor, this is why a lot of turboed engines dont need an exhaust, as the heat is what causes the noise from an exhaust, it is the heat cooling that is the noise you hear.
But i do agree that turbos not set up right will cause heat problems elsewhere in the motor.
Nothing wrong with any rotax for that matter less weight and the best power to weight going.
But i guess for people who dont really need this it is point less to keep bringing this up

[Disco]

Heat from the exhaust didn't cause my prop to fail down at the root inside the aluminum hub.  Heat did cause the skins to blister a bit further up the blade tho.

[Chopper Reid]

Actually Brain, i challege you on that thought,  the turbo ACTUALLY takes heat out of the exhaust gasses, it needs to do this to generate the power to pump air for the motor, this is why a lot of turboed engines dont need an exhaust, as the heat is what causes the noise from an exhaust, it is the heat cooling that is the noise you hear.
But i do agree that turbos not set up right will cause heat problems elsewhere in the motor.
Nothing wrong with any rotax for that matter less weight and the best power to weight going.
But i guess for people who dont really need this it is point less to keep bringing this up

You are correct Bones, and you are also correct in saying that turbos not set up can create havoc with increased temps, usually in the bits that dont really need any more heating. I'm also a bit biased re turbos, unless its a 914, or else you are a social flyer, then leave the anchors in the box and get a real engine!! I had so much trouble with my first engine on this gyro that I nearly gave away flying [factory turboed EA 82] !!! Having said that, I reckon all Diesels should have hair dryers,


I have seen a photo of your exhaust set up Disco and while I'm no techy, the exhaust could be better directed away towards the tip so as to dissipate whatever heat that is being produced.