Billzilla

I'm perplexed as to what your nosewheel has to do with the autopilot?

Many airline landings don't even take the crab off. Bit hard on the airframe.. Nev

FWIW a 747 doing an autoland does not take the crab angle off for touchdown and they are rated at 22 kts of crosswind. Just plant it on the runway and let inertia straighten it all up.

You're too modest Bill, tell them your association with 737's and this thread .....

I actually like crosswind landings, they make it more interesting.

So here comes the predictable story .....

Had to take a Metro 2 into Cooly for most of the week with a full 30 kts blowing across the main runway. The problem was the demonstrated max for them is only 20 kts so it was a bit of a handful.

The technique was the make the approach normally but with a little more airspeed, then do the usual boot-full of rudder and drop the upwind wing. The problem with that was even with full rudder the aeroplane still wasn't straight with the centreline so I had to take one hand off the controls (it's pretty normal to land a Metro in rough conditions with both hands on the controls as they're quite heavy, and just plant it with approach power on) and cut the power on the downwind engine, and that would yaw the aeroplane enough to get it straight. Next problem was even though the Metro 2 has very stubby wings, the upwind one was down so far I was worried it'd scrape the runway before the main wheel touched down. But fortunately it never did and I was able to just plant the heap of Metro onto the runway, keep full rudder on and then use lots of asymmetric thrust to keep it on the centreline.

All good fun.

They are represented more on Air Crash Investigations, purely because they are the most sold and currently flown airliner ever produced.

Indeedy they are.

I don't know if it's still true, but for a long time the saying was that Boeing had made more 737's than Airbus had made Airbuses.

Oh that's interesting, Boeing got the MTOW weights wrong on the 747-200 and 300.

They show the MTOW as 833,000 lbs but got the kilograms incorrect at 374,850 kg. It's actually 377.8 tonnes.

Edit - I had a look on the Boeing site and found the same numbers on the Wikipedia site.

On Wikipedia there's some brief information and it shows the difference though -

747-400 - 216,840 L

747-400ER - 241,140 L

747-400F - 216,840 L

http://en.wikipedia.org/wiki/Boeing_747-400#Specifications

And

http://www.boeing.com/boeing/commercial/747family/pf/pf_400er_prod.page

http://www.boeing.com/boeing/commercial/747family/pf/pf_400f_prod.page

Just from watching the 747 crash thread carefully in Pprune and talking to various 747-400 drivers over the years. All of them have said the freighters don't have tail tanks.

I'm not rated on the -400 but I've got about 5,000 hours on the -100,-200, and -300's

I can't verify claims of others that freighter versions don't use tail tanks as I never played with fuel systems on freighter versions, however I note on the Boeing website that the fuel capacity specs are idential for PAX and freighter versions of the -400, so my gut feeling is that the tail tank does exist, but someone may be able to prove me wrong on this one .

Many of the big intercontenental jets carry quite a bit of fuel in the fixed horiz stab.

Some of the -400 passenger ones do, none of the -400 freighters do though. Nor the converted ones.

Not something that pushing the nose down could avoid if the W+B is out beyond elevator authority. As for "righting" itself, are they not designed to have the dragline in a stalled condition rearward to aid with recovery? i had thought that once stalled it would have helped the nose to lower and slowly aid recovery

As usual, it's best until we can read the official report so we have an idea as to what went on. Until then speculation probably won't help.

No doubt the panel would have been lighting up like a Xmas tree at that high alpha and obvious low airspeed toward the top, stick-shaker and all probabily. Hard to imagine somebody didn't try to push the nose down, which leads me to think they couldn't for some reason............time will tell on this unfortunate incident.............................Maj...

The Alpha Floor warning would have been blaring away for sure though.

I heard an interesting theory - the pilots may have punched the wrong numbers into the computer when doing their takeoff calculations and so the plane over-rotated after V1. Or the computer malfunctioned. It could be that the PIC realised too late what was happening and was too late to switch to manual control to recover. That could explain the fact that it nearly righted itself before hitting the ground, as opposed to hitting the ground tail-first which it should have if there was a significant load shift to the aft.

On the -400's the pilots enter in the weights of the fuel and ZFW (Zero Fuel Weight) into the FMS (Flight Management System, by Honeywell) and from that combined weight and airport location to work out the various V-speeds that are then confirmed manually out of the books by the other pilot.

The only automatics used to takeoff on the 747's is the autothrottle and that just goes for either a target EPR (Engine Pressure ratio) or %N1 (fan speed, in the case of GE engines)

The reason it 'righted itself' was still due to a very rearwards Cog, I suspect.

Best wait until the official reports come out anyway.

747's are pretty insensitive to a few tonnes here or there but 12 tonnes would be very difficult to combat if it moved down towards the tail. They were dead just after they left the ground. :(

I'm not going to be there - too far away - but I've been doing TIG welding for a couple of years now and it's a very good thing to learn.

"What survival gear do you ALWAYS carry on every flight?"

Pen, passport, credit card. :)

The citation in the wiki article just cites the You Tube video. All the other references link back to the same video.Still not convinced.....

I still believe the one wing video is a hoax. I can't believe any aircraft would be controllable with that much aerodynamic imbalance.

And ...

http://www.uss-bennington.org/phz-nowing-f15.html

Yep the F-15 with only one wing is real.

http://www.youtube.com/results?search_query=F15+one+wing&aq=f

The fuselage on them creates a fair bit of the lift so the pilot was able to make a very fast approach (250 kts or so I think) and land.

Once you've got an ugly-copter or whatever it happens to be called, (thats not important providing it flies well) Whats a ball park figure that one needs to outlay, to get great footage like this from the air?I used to fly aerobatic kites (decades ago) with a third-string to operate an on-board camera.

Results like this would have been unheard of then, but i'm led to believe that they've even improved on the crystal set in recent years.

For the copter I'd just get a package deal, something like this

You need radio gear to control is

FPV gear

And a GoPro camera

The Mongrel's Shop

So yeah it adds up pretty quickly but if you shop around you can do a bit better. The guy in the links above is the one I use here in Australia.

Fiction.

The problem of failures in any machine - electric or ICE - can be reduced greatly by applying a couple of practices; Either lifing components and/or regular inspections to determine if they are within safe specifications.

It's why airliners are so safe and reliable.

Yes, like powered flight! Many theorist said this would be "impossible", but Wilbur and Orville did it in the 20th century to the chagrin of all the theorists of the day. It took over five years before many in the western world really believed it. Many skeptical people would only believe it when they saw powered flight with their own eyes.

And yes the march of technology goes on. Look at the latest lithium batteries and compare them to the best of the nickel-cadmium units of twenty years ago. The lithium ones are vastly better in every way. The next generation of batteries is going to be better but I don't know what form they will take. As I've mentioned I'm a fan of graphene batteries though. Maybe zinc, who know?

I think the current problem can be pretty much summarised in two words: battery capacity.Until the battery capacity kg/kg comes reasonably close to mogas or avgas, large-scale adoption of electric flight is not going to happen.

A good petrol engine is going to be about 30% efficient (depending on how you measure it) while a good electric motor is comfortably over 90%. So when batteries get up around 1/3 the energy density of petrol then they'll be pretty close to the same endurance. I have everything crossed for graphene battery technology.

Actually Bill I saw a few sets of conrods that would suit that at Erzhong in my city a few weeks ago, I wonder if they get them made here.Have a look around Erzhongs website, it's the the biggest general engineering works in the world .. http://www.china-erzhong.com/erzhong-en/dy/ShowArticle.asp?ArticleID=887

 

If you go to 'Facility Capability', 'Forging Capability' and have a look at the 2nd small 3D picture of an 800MN press, I can tell you it's very real and I have stood in front of it with my jaw on the ground, it's indescribably massive. It's soon to be commissioned and Rolls Royce are waiting for it to press turbine housings and other parts for their next generation ginormous jet engine that can't be made until this particular press is finished.

Wouldn't want to get your fingers caught in it.