What are pros and cons of carbon fibre aircraft, specifically in hot humid North Queensland

[DrZoos]

My aircraft clearly states , not to be flown in ambient temps above 40c...when i enquired why they said the "resins and glues " used lose strength while at higher temps and regain strength after they cool again

 

 

[jetjr]

I believe this is the case on new resins, they harden further and become stronger over time.

 

I think this is limit for ambient cured types - someone else confirm?

 

 

[Oscar]

My aircraft clearly states , not to be flown in ambient temps above 40c...when i enquired why they said the "resins and glues " used lose strength while at higher temps and regain strength after they cool again

Yep, that's basically correct. Sufficiently correct that one should NOT jump into one's composite aircraft ( whether a c/f composite OR a basic e-glass and commercial resin composite structure, such as a Jabiru) that had been sitting out on the hard in a blinding sun and a 40C+ ambient day and blast off into the wild blue.

 

 

[cscotthendry]

I was asked by the American distributors of the Legend how it performs on a 120F-130F day. 130F is somewhere north of 50C I think, and it got me to wondering where you would get those kinds of temps. Then I thought of the aircraft sitting on a black bitumen runway with the ambient air temps in the 40s. Would the temps over the runway in those conditions get up to 50C?

 

Something to consider for us Tupperware drivers?

 

 

[Bruce Tuncks]

Gliders do it all the time. The over 40 degree days are when the thermals are the best. Gosh its good when you climb over 5000 ft and the vents start to blow some cool air in. Jabirus don't come out on these days.

 

 

[Nobody]

CS-22, the design standard regularly applied to the design of gliders, says that you have to use the material at the highest normal operating temperature if the strength is affected by temperature. It also nominates 54 degrees as the "normal operating conditions"

 

See clauses CS 22.613 and AMC 22.613©

 

I am not sure what the ASTM requires and dont have it to hand at the moment.

 

 

[jetjr]

plenty ive seen flying over 40 deg, not much fun though.

 

Once moving cools quickly

 

 

[Kiwi303]

I went and looked at the West Systems website.

 

A bit of Wikipedia first.

 

The heat deflection temperature or heat distortion temperature (HDT, HDTUL, or DTUL) is the temperature at which a polymer or plastic sample deforms under a specified load. This property of a given plastic material is applied in many aspects of product design, engineering, and manufacture of products using thermoplastic components.

 

Determination

 

The heat distortion temperature is determined by the following test procedure outlined in ASTM D648. The test specimen is loaded in three-point bending in the edgewise direction. The outer fiber stress used for testing is either 0.455 MPa or 1.82 MPa, and the temperature is increased at 2 °C/min until the specimen deflects 0.25 mm. This is similar to the test procedure defined in the ISO 75 standard.

 

The lowest HDT listed on the 105 resin family page was 117*F.

 

http://www.westsystem.com/ss/typical-physical-properties/

 

So anything under 47*C and you're good.

 

 

[SDQDI]

Remembering that is not daytime air temp but the temp of the actual material. Any colour other than white could hit 47 quite easily on a moderate temperatured sunny day.

 

 

[Pearo]

I went and looked at the West Systems website.

A bit of Wikipedia first.

 

The heat deflection temperature or heat distortion temperature (HDT, HDTUL, or DTUL) is the temperature at which a polymer or plastic sample deforms under a specified load. This property of a given plastic material is applied in many aspects of product design, engineering, and manufacture of products using thermoplastic components.

 

Determination

 

The heat distortion temperature is determined by the following test procedure outlined in ASTM D648. The test specimen is loaded in three-point bending in the edgewise direction. The outer fiber stress used for testing is either 0.455 MPa or 1.82 MPa, and the temperature is increased at 2 °C/min until the specimen deflects 0.25 mm. This is similar to the test procedure defined in the ISO 75 standard.

 

The lowest HDT listed on the 105 resin family page was 117*F.

 

http://www.westsystem.com/ss/typical-physical-properties/

 

So anything under 47*C and you're good.

Which aircraft manufacturers use West System 105? (note I do use WS 105 with carbon, but that is on foils immersed in water!)

 

 

[Kiwi303]

Which aircraft manufacturers use West System 105? (note I do use WS 105 with carbon, but that is on foils immersed in water!)

Manufacturers I don't know, but it's a popular home build resin system. Simple, convenient and on a par with pretty much any other consumer available system.

 

 

[dutchroll]

Gliders do it all the time. The over 40 degree days are when the thermals are the best. Gosh its good when you climb over 5000 ft and the vents start to blow some cool air in. Jabirus don't come out on these days.

No one comes out on those days. Except slightly batty glider pilots.

 

 

[M61A1]

I've actually grown to enjoy those days....much cooler in the Drifter at 2000-5000 in jeans and t shirt than on the ground, and the bumps are fun.

 

 

[dutchroll]

.......and crazy Drifter pilots.

 

Aside from that, the normal people are inside with the A/C on enjoying an ice cold beer.

 

 

[M61A1]

Watch the news.....when it gets hot, the old "normal" people are first to die when the ac fails. Got aircon in the Drifter.anyway, just find a "comfortable" altitude. Got no air cycle machine like the Boeing drivers.