75ZT Community

Just like MPs, why use one word when a hundred can say the same thing.......

stevemac wrote:

Bernard wrote:Well, I always thought that lift was produced by the angle of attack of the wings meeting the airflow. and being deflected by it.

You are right Bernard. Being deflected downwards

Plains, Flight! all inspired by nature.............. the common bird has a lot to answer for.....



Oh! and Kangaroos can not walk backwards........ hows that for a fact!

Dallas wrote:
Plains, Flight! all inspired by nature..

Now, I have no idea how plains fly. I didn't think they did

That just about sums up the Aerodynamic Theory Exams I took at the CAA a few years ago................did you know that the horizontal stabilizer ( tailplane) on a 747 is infact an upside down wing, if you look at one,the lower surface has a convex curve.Quite the reverse of the wing.This to do with centre of pressure(lift) of the main wing.As you approach the speed of sound,the pressure moves aft and as a result of trim change with the centre of gravity,you get a nose pitch down moment(old aircraft suffered from this with tragic results sometimes).By the tailplane generating a negative moment,nose up pitch is restored.Right,enough from me...this is too much like the theory classrooms at work!!!
On a lighter note,here is a little clip of flight and shows the theory of the conservation of energy and a quite brilliant pilot..Mr Bob Hoover..............oh and don't try the iced tea trick next time you fly!!
http://www.youtube.com/watch?v=5hjVxQ1kKVk

podge wrote: and a quite brilliant pilot..Mr Bob Hoover

Indeed!

podge wrote:s infact an upside down wing, if you look at one,the lower surface has a convex curve.Quite the reverse of the wing.This to do with centre of pressure(lift) of the main wing.As you approach the speed of sound,the pressure moves aft and as a result of trim change with the centre of gravity,you get a nose pitch down moment(old aircraft suffered from this with tragic results sometimes).By the tailplane generating a negative moment,nose up pitch is restored

Never realised that. I am sure we have had this conversation before Pete in the dim and distant past.

I think we may have Steve.Concorde suffered from centre of pressure shift in a really big way.The clever bit in getting the trim right as she accelerated to Mach 2 was to pump fuel into an aft tank,then,as she deaccelerated the fuel was pumped forwards. Its all in the pictures:
http://heritageconcorde.com/?page_id=6793

podge wrote:I think we may have Steve.Concorde suffered from centre of pressure shift in a really big way.The clever bit in getting the trim right as she accelerated to Mach 2 was to pump fuel into an aft tank,then,as she deaccelerated the fuel was pumped forwards. Its all in the pictures:
http://heritageconcorde.com/?page_id=6793

I'm quite proud of the fact that I worked on the design and development of the control valves for this function many, many years ago.

She was a class act in every way Bernard,beautiful "under the skin",I have a set of polished up elevon bearings on the mantle piece........ones that I changed.People allways have a chat when they realize you worked on her.............its not showing off...just being very proud as you say.What did we throw away....................

podge wrote:She was a class act in every way Bernard,beautiful "under the skin",I have a set of polished up elevon bearings on the mantle piece........ones that I changed.People allways have a chat when they realize you worked on her.............its not showing off...just being very proud as you say.What did we throw away....................

What was even worse was the TSR2, developed in tandem.
What isn't generally known is that all designers of every last little module were told to start with a blank drawing board; every part had to be new and not borrowed from elsewhere.
No doubt one of the reasons the costs skyrocketed.
It made it more exciting though....

Please don't get me going on TSR2.......that was in my Avatar on "the other side".A brilliant airframe in every way.............did you know Airfix issued a kit of it last year.
"Rolly" Beaumont ,its test pilot,never got over the scandalous way this project was treated.A lot of the guys I work with worked on the prototypes and even after all these years your can sense their disbelief.If you ever go up to RAF Cosford and stand by that stunning machine,its worth to listen to the comments when people see her for the first time.A link from my favourites..........
http://www.youtube.com/watch?v=uTM4ve3vZYY

podge wrote:If you ever go up to RAF Cosford and stand by that stunning machine,its worth to listen to the comments when people see her for the first time

Unfortunately, the miniaturized avionics suite, years ahead of anything anybody else could achieve, has been stripped out

I've seen and handled some of those instruments and stand in awe of those who could design, develop and manufacture such exquisite engineering.

Perchance this Paul.................I took it a couple of years ago.......

podge wrote:I think we may have Steve.Concorde suffered from centre of pressure shift in a really big way.The clever bit in getting the trim right as she accelerated to Mach 2 was to pump fuel into an aft tank,then,as she deaccelerated the fuel was pumped forwards. Its all in the pictures:
http://heritageconcorde.com/?page_id=6793

I take it they did not use the same pump as in the MkI version of our cars.

Now this is what I call a fuel pump........over 4 litres/V12/450BHP!!!!!!!!!!!!

http://www.eurekamagazine.co.uk/article ... -pump.aspx
Mind you,these are probably the most powerful fuel pumps ever.........any ideas where they came from .just look at the figures!!..........

"A gas-generator was used to drive a turbine which in turn drove separate fuel and oxygen pumps, each feeding the thrust chamber assembly. The turbine was driven at 5,500 RPM by the gas generator, producing 55,000 brake horsepower (41 MW). The fuel pump produced 15,471 gallons (58,564 litres) of RP-1 per minute while the oxidizer pump delivered 24,811 gal (93,920 l) of liquid oxygen per minute"............PER MINUTE!!!!!!!!!!!!!!!!!

The circumference of the Earth in kilometers is 40,075 km, and the circumference of the Earth in miles is 24,901. In other words, if you could drive your car around the equator of the Earth (yes, even over the oceans), you’d put on an extra 40,075 km on the odometer. It would take you almost 17 days driving at 100 km/hour, 24 hours a day to complete that journey.

If you like, you can calculate the Earth’s circumference yourself. The formula for calculating the circumference of a sphere is 2 x pi x radius. So, the radius of the Earth is 6371 km. Plug that into the formula, and you get 2 x 3.1415 x 6378.1 = 40,074. It would be more accurate if you use more digits for pi.

You might be interested to know that the circumference of the Earth is different depending on how you measure it. If you measure the circumference around the Earth’s equator, you get the 40,075 km figure I mentioned up to. But if you measure it from pole to pole, you get 40,007 km. This is because the Earth isn’t a perfect sphere; it bulges around the equator because it’s rotating on its axis. The Earth is a flattened sphere, and so the distance around the equator is further than the circumference around the poles.

Want some comparison? The circumference of the Moon is 10,921 km, and the circumference of Jupiter is 500,000 km.

Here are a bunch of measurements for you:
Circumference of the Earth in kilometers: 40,075 km
Circumference of the Earth in meters: 40,075,000 meters
Circumference of the Earth in centimeters: 4,007,500,000 centimeters

Circumference of the Earth in miles: 24,901 miles
Circumference of the Earth in feet: 131,477,280 feet
Circumference of the Earth in inches: 1,577,727,360 inches