You may be at the city centre but what do you do? I dont understand why you claim commposite structures used for some of the parts you talk about are cured at 220F (94C) for 6 hours. Most parts would take 16+ hours at that temperature and at the thicknesses you talk off.

No one has ever claimed that composites are a panecea do a search on composites and you will see the same. However some of the things you claim are pretty obscure and maybe they were an issue say 20 years ago but not any more.

Any way we shall have to agree to dis agree..

What I actually do is of no consequence here.
The cure temps vary from 80 deg C (M9 series) to 180 deg C. Phenolics are about 135. I should have typed 250F thinking about it, but we do use a lot at 220F at a very high pressure.
The cure cycle can be up to 24 hours in some cases, but as said before, most of that time is heat up and cool down. The actual cure at full temp and full pressure is 6 hours average, and in some cases 10 hours. Very few parts take a cure cycle of up to 16 hours, unless the mold is so massive it takes a long time to heat up. Such a large mold would be Invar too, even longer to warm.
My “Claims” are not obscure neither are they old hat. A decent google will assist you. Read research stuff, not the claims of the Aerospace industry. You have not actually challenged my “Obscure” remarks, you have just said they are wrong. I see no facts/figures/credence coming from your side.

Ohhhh no……

Paul

I wouldn’t downgrade from a 400D to a 1000.
I chose Canon 450D when it was a fortnight old, simply because it felt better in my suitcase sized hands than the Nikons of similar price.
Yes, it does appear slightly soft when direct from Camera. All digital images need a sharpen anyway (By their very nature) so Raw into Lightroom for Developing, into to Photoshop for fine tuning/cropping/printing. I also use Genuine Fractals if I’m upsizing from a severe crop.
As for the Kit lenses, yes they are poor on the 450D and the 1000. Plastic rubbish, low cost glassware. ASAP move up to “Gold Ringed” stuff or even better, L series.

…and those are his footprints, right there.

Where on the Stairs?…right there.

They’re native plants to New Zealand with Maori names completely unpronouncable to Europeans.
http://www.ccc.govt.nz/cityleisure/artsculture/artinthecity/chalice/aboutchalice.aspx

Well, I reckon the Maori smoked a lot of those!

Ah, that only comes out for special occasions, like winning the Premier League and suchlike.

Back on topic now, you rascal! 😉

We did you lot a favour last Saturday.

Where do you think we will sort out next?
Iran?
Korea?

Dont need to use BMI’s, and yes as mentioned before there are issues with regards to temperature but mostly for military aircraft which are expected to see hi temperatures in normal use (impact, being shot at etc etc) and some of them do use BMI’s PI’s etc..

BMI’s are used around the hot areas of engine bays or APU bays. Not as impact resistance.
However for civilian aircraft the requirements may not state that the structure needs to survive a fire, depending on what and where it is, it needs to survive long enough to allow the passangers to exit in a safe and controlled manner..
Not sure if it is scare mongering or lack of understanding.

Oh, I understand a great deal. Do you think I can rattle this stuff off without being in the game?
“Exit in a safe manner”. Yes, I’ve taken part in the evacuation licencing. We rehearsed it 5 times to ensure we got out in 2 mins. That aside, the Ali will retain structural integrity for several more minutes than a CFRP. That may be enough to get on the ground.

Fair point but aircraft with composite skins d noses, wing spars have been flying or are being certified to fly what do you know that the authority and industry do not know?
The A400 is the first large A/c to fly with Carbon Main Spars and large primary structures. The Carbon main Spars in the air at the moment (Not A400) are on Fighters or the B2. The differing reasons are listed in my other post.
I’m in the industry, and have been for 35 years, thanks.

can you share your source?

If the truth about the places I work is given, it would put me in a difficult position. I am involved with AUK, Airbus Military, MoD, DoD, Boeing, Bombardier and a smattering of others.

Source again please.. also Boeing may be having issues but this is not the same as the whole industry having trouble.

Sorry, “The whole industry” I was referring to the 3 major players in the CFRP lark which are likely to be taking pax. in the next 5 years.

Aluminium went through the same issues back in the 50’s and 60’s with jet aircraft. Should they have gone back to metal and fabric constructions?

temperatures for curing are usually a lot higher than 220F and times are usually in excess of 6 hours unless you talk of only working with 2 mm thick structures. HW Tg of over 120C is usually the order of the day. Dry Tg’s of over 170/190 are usually order of the day.

Sorry, but that is just wrong. The autoclaves temp is around 220F (Hotter for BMI), the cure cylce can be 12 or 18 hours, but the first few hours is to get the tools up to temprature and the last few hours is to let them cool down (All under pressure of course)
This is for thicknesses of upto 28mm, woven and UD.

Please provide source specially about issues on the A400 and the A350 as one is already flying (A400M) meaning it must have passed enough regs and A350 is probably still in the development phase.

Both these are of course true. I will try and find out on Monday how much leeway is given to military test flights, there is some but cannot remember.

Not been solved? Source? Also what makes you think it will be a massive weight and cost? if that was the case do you think the industry would even care about composites?

The perfect wallnut whipping of a bolt tail has not been solved. And, how do you check every one, after every flight? Upon a lightning tap, hot Plasma gas (Basically superheated air) can expand from the gap between the bolt and it’s hole (Measured in microns). This can be stopped with a perfect seal or the use of a special kind of fastener (At about 30 x the cost of a standard fastener…which for CFRP are at leat 4 times the price of a standard for Ally.)
Massive weight and cost because the amount of metalwork that is needed to divert the strike back to home will significantly increase the weight. The cost is in the promises made to airlines that the platform will weight X and it turns out to be X1.2. Cost of production (If CFRP is directly swapped with metal) would be cheaper than an all CFRP solution. But, the metal is an addition to the CFRP, making even more production costs. Composites are fine and dandy, they reduce the weight of stuff like U/c doors, panels, spoilers, noses, fairings of any sort. Part count for a panel is literally decimated, often even less than 10% so of course the industry loves CFRP…..but now it’s surrounding the fuel and a very different ball game is in play.

A lot of people still make a lot of money from ali structures if the potential for cost and weight savings did not exist people would not be looking into composites.
In this lark, the pursuit of “Weight off” will never, ever cease.

Would be interesting to see what sources you have to make such bold comments.

As the answer somewhere above.

In the text.