Facts that shocked you

[Austin Prefect]

Arnold Cunningham said:

And yet, at top speed the X-15 still started to disintegrate! Bonkers aeroplane.

I think the mentality at the time was that if your test aircraft can hit top speed without starting to disintegrate, it can take more power.

[Austin Prefect]

You can get the same radiation dose from sleeping next to someone as from being in a nuclear power station. So sex next to a nuclear reactor is probably a bad idea.

[Tango13]

Nicks90 said:

The thing with these drag cars that always astound me, if they average about 7500rpm during their run, from start to finish the engines only turn over 500 revs!!!

500 revolutions to deploy enough power to launch a car weighing nearly a tonne to in excess of 300mph in less than 4 seconds

Look at it another way... They run a V8 engine producing about 12,000 horsepower, so each single cylinder is making as much power as one and a half Bugatti Veyrons

[Tango13]

Austin Prefect said:

Arnold Cunningham said:

And yet, at top speed the X-15 still started to disintegrate! Bonkers aeroplane.

I think the mentality at the time was that if your test aircraft can hit top speed without starting to disintegrate, it can take more power.

Nope, not at all, the X-15 had way more power than it needed, the XLR-99 rocket motor was actually throttlable, they didn't always use full thrust and would sometimes even use the airbrakes to control the energy of a flight profile.

The reason the X-15 started to melt was the airflow from an externally mounted experiment buggered up the airflow in such a way as to cause a 'hotspot' which melted part of the airframe. Bearing in mind it was made from Inconel X which is something like 90% nickel it shows just how hot the X-15 was getting.

[hidetheelephants]

Austin Prefect said:

You can get the same radiation dose from sleeping next to someone as from being in a nuclear power station. So sex next to a nuclear reactor is probably a bad idea.

Avoid bananas and air travel, also no holidays in Ramsar or in places at high altitude like Denver. Or not, because environmental exposure is normal and not meaningfully a health risk(although the stats are a bit wobbly for pilots and cabin crew).

[CoolC]

hidetheelephants said:

Austin Prefect said:

You can get the same radiation dose from sleeping next to someone as from being in a nuclear power station. So sex next to a nuclear reactor is probably a bad idea.

Avoid bananas and air travel, also no holidays in Ramsar or in places at high altitude like Denver. Or not, because environmental exposure is normal and not meaningfully a health risk(although the stats are a bit wobbly for pilots and cabin crew).

Isn't there also something about Brazil nuts containing radiation naturally? Enough to set off the alarms in a nuclear power plant?

Might be completely miss-remembering something from a pub quiz 25 years ago though.

[eldar]

hidetheelephants said:

Austin Prefect said:

You can get the same radiation dose from sleeping next to someone as from being in a nuclear power station. So sex next to a nuclear reactor is probably a bad idea.

Avoid bananas and air travel, also no holidays in Ramsar or in places at high altitude like Denver. Or not, because environmental exposure is normal and not meaningfully a health risk(although the stats are a bit wobbly for pilots and cabin crew).

Beware the banana.

https://en.wikipedia.org/wiki/Banana_equivalent_do...

[98elise]

Nicks90 said:

DodgyGeezer said:

Iirc they run virtually hydrolocked - some pix of them getting off the line are pretty awesome too

The thing with these drag cars that always astound me, if they average about 7500rpm during their run, from start to finish the engines only turn over 500 revs!!!

500 revolutions to deploy enough power to launch a car weighing nearly a tonne to in excess of 300mph in less than 4 seconds

These facts were doing the rounds a few years ago....

One Top Fuel dragster 500 cubic-inch Hemi engine makes more horsepower (8,000 HP) than the first 4 rows at the Daytona 500.

• Under full throttle, a dragster engine consumes 11.2 gallons of nitro methane per second; a fully loaded 747 consumes jet fuel at the same rate with 25% less energy being produced.

• A stock Dodge Hemi V8 engine cannot produce enough power to merely drive the dragster's supercharger.

• With 3000 CFM of air being rammed in by the supercharger on overdrive, the fuel mixture is compressed into a near-solid form before ignition. Cylinders run on the verge of hydraulic lock at full throttle.

• At the stoichiometric 1.7:1 air/fuel mixture for nitro methane the flame front temperature measures 7050 degrees F.

• Nitromethane burns yellow. The spectacular white flame seen above the stacks at night is raw burning hydrogen, dissociated from atmospheric water vapor by the searing exhaust gases.

• Dual magnetos supply 44 amps to each spark plug.

This is the output of an arc welder in each cylinder.

• Spark plug electrodes are totally consumed during a pass. After 1/2 way, the engine is dieseling from compression plus the glow of exhaust valves at 1400 degrees F. The engine can only be shut down by cutting the fuel flow.

• If spark momentarily fails early in the run, unburned nitro builds up in the affected cylinders and then explodes with sufficient force to blow cylinder heads off the block in pieces or split the block in half.

• Dragsters reach over 300 MPH before you have completed reading this sentence.

• In order to exceed 300 MPH in 4.5 seconds, dragsters must accelerate an average of over 4 G's. In order to reach 200 MPH well before half-track, the launch acce leration approaches 8 G's.

• Top Fuel engines turn approximately 540 revolutions from light to light!

• Including the burnout, the engine must only survive 900 revolutions under load.

• The redline is actually quite high at 9500 RPM.

• THE BOTTOM LINE: Assuming all the equipment is paid off, the crew worked for free, & for once, NOTHING BLOWS UP, each run costs an estimated $1,000 per second.

[Error_404_Username_not_found]

98elise said:

A lot of stuff about dragsters...

Blimey. Makes you think a bit dunnit?
Some genuinely astonishing facts there mate.

[Exasperated]

98elise said:

These facts were doing the rounds a few years ago....

One Top Fuel dragster 500 cubic-inch Hemi engine makes more horsepower (8,000 HP) than the first 4 rows at the Daytona 500.

• Under full throttle, a dragster engine consumes 11.2 gallons of nitro methane per second; a fully loaded 747 consumes jet fuel at the same rate with 25% less energy being produced.

• A stock Dodge Hemi V8 engine cannot produce enough power to merely drive the dragster's supercharger.

• With 3000 CFM of air being rammed in by the supercharger on overdrive, the fuel mixture is compressed into a near-solid form before ignition. Cylinders run on the verge of hydraulic lock at full throttle.

• At the stoichiometric 1.7:1 air/fuel mixture for nitro methane the flame front temperature measures 7050 degrees F.

• Nitromethane burns yellow. The spectacular white flame seen above the stacks at night is raw burning hydrogen, dissociated from atmospheric water vapor by the searing exhaust gases.

• Dual magnetos supply 44 amps to each spark plug.

This is the output of an arc welder in each cylinder.

• Spark plug electrodes are totally consumed during a pass. After 1/2 way, the engine is dieseling from compression plus the glow of exhaust valves at 1400 degrees F. The engine can only be shut down by cutting the fuel flow.

• If spark momentarily fails early in the run, unburned nitro builds up in the affected cylinders and then explodes with sufficient force to blow cylinder heads off the block in pieces or split the block in half.

• Dragsters reach over 300 MPH before you have completed reading this sentence.

• In order to exceed 300 MPH in 4.5 seconds, dragsters must accelerate an average of over 4 G's. In order to reach 200 MPH well before half-track, the launch acce leration approaches 8 G's.

• Top Fuel engines turn approximately 540 revolutions from light to light!

• Including the burnout, the engine must only survive 900 revolutions under load.

• The redline is actually quite high at 9500 RPM.

• THE BOTTOM LINE: Assuming all the equipment is paid off, the crew worked for free, & for once, NOTHING BLOWS UP, each run costs an estimated $1,000 per second.

• And they'll still have a rusting Transit behind them, flashing its headlights

[bigothunter]

98elise said:

These facts were doing the rounds a few years ago....

• In order to exceed 300 MPH in 4.5 seconds, dragsters must accelerate an average of over 4 G's. In order to reach 200 MPH well before half-track, the launch acceleration approaches 8 G's.

The Swift S-1 aerobatic glider is stressed for plus and minus 10g (service limits +10 g / -7.5 g). Speed is limited to 320 km/h. It doesn't have an engine.

https://allaboutplane.weebly.com/swift-s-1.html

[RizzoTheRat]

Another silly one on engines and power...

A question our propulsion lecturer set many years ago to calculate the power of a fuel pump on the space shuttle. Most people assumed they'd got it wrong when they came out with an answer of around 60MW (around 80,000 horse power).

A 37000 rpm turbopump shifting about 12 tonnes per minute of liquid hydrogen at 450 Bar

[Cotty]

bigothunter said:

The Swift S-1 aerobatic glider is stressed for plus and minus 10g (service limits +10 g / -7.5 g). Speed is limited to 320 km/h. It doesn't have an engine.

https://allaboutplane.weebly.com/swift-s-1.html

It still needs to get up there in the first place, aren't gliders either towed by another plane or attached to a winch to launch.

[bigothunter]

Cotty said:

It still needs to get up there in the first place, aren't gliders either towed by another plane or attached to a winch to launch.

Yep kinetic energy (converted from potential) is needed for aerobatic manoeuvers. You can't perform aerobatics at ground level. Usually aerobatic gliders are launched by aerotow, typically to 3500ft.

[Tango13]

RizzoTheRat said:

Another silly one on engines and power...

A question our propulsion lecturer set many years ago to calculate the power of a fuel pump on the space shuttle. Most people assumed they'd got it wrong when they came out with an answer of around 60MW (around 80,000 horse power).

A 37000 rpm turbopump shifting about 12 tonnes per minute of liquid hydrogen at 450 Bar

Steam driven too iirc?

[Austin Prefect]

Da Vinci is believed to have painted 2 Mona Lisas. The lesser known one appears to be of her prettier younger sister and is currently in Isleworth.

[WrekinCrew]

Austin Prefect said:

Da Vinci is believed to have painted 2 Mona Lisas. The lesser known one appears to be of her prettier younger sister and is currently in Isleworth.

I'm just reading Matt Parker's maths book Love Triangle". Hope it's OK to quote a bit:

With parallax we get to some real triangles. This is the effect where, if you move your point of view around, objects seem to change their alignment. Which can be very insightful. For example, many copies of the Mona Lisa exist, some of which were produced in Leonardo da Vinci’s own studio by his fellow painters. But when one ‘copy’ of the Mona Lisa was cleaned in 2012 the conservators noticed that her hands, face, and clothes all lined up slightly differently. This parallax effect meant they could tell that this was not a mere duplication of the original as previously thought, but rather was painted by someone else at the same time as the original.

[mkjess123]

Currently sat in a hospital room waiting for my wife to wake up following an operation. We had.to be here at 7am ready to go.
Astounded that three patients booked in for ops this morning haven't turned up.
Staff just rolled their eyes and said this was a regular occurrence!

[hidetheelephants]

mkjess123 said:

Currently sat in a hospital room waiting for my wife to wake up following an operation. We had.to be here at 7am ready to go.
Astounded that three patients booked in for ops this morning haven't turned up.
Staff just rolled their eyes and said this was a regular occurrence!

Expecting patients to turn up at 7 am seems like a good way to not have them turn up unless they live locally, in most places public transport won't get you there.

[mkjess123]

Having an operation is a serious part of somebody's life and involves substantial costs to the NHS or whoever.
Surgeons, doctors, and other highly qualified professional people are involved and an excuse about public transport just doesn't hold any water. We live 80+ miles away and managed it!