News from FsLabs...good!

[jcomm 5,928]

17 minutes ago, Ray Proudfoot said:

Woops! 🤣 I knew the conditions were different in the tropics so thanks for the correction.

Itr's all due to the spinning ....  Fatter at lower abs(LAT), thinner towards the Poles 🙂

Edited March 15, 2022 by jcomm

[SimeonWilbury 220]

14 minutes ago, jcomm said:

Itr's all due to the spinning ....  Fatter at lower abs(LAT), thinner towards the Poles 🙂

I always find it interesting how how the environment of the Earth subtly effects things at so many levels due to these kind of irregulatities!

iirc the 'Fat-Earth' phenomenon is also what makes sun-synchronous orbits for satellites possible given that the same bulge affecting atmospheric density also causes the orbital plane to shift over time, so your target can always be photographed at the same time of day regardless of the time of year - so not just useful for if you're looking to take a Concorde higher & further!

Edited March 15, 2022 by SimeonWilbury

[MarkW 1,491]

1 hour ago, SimeonWilbury said:

 

iirc the 'Fat-Earth' phenomenon 

I read this as "Flat Earth" and was like....ok here we go.

[MarkW 1,491]

Hey, if anyone wants to study up on the Concorde Fuel system, you can watch my fantastic video here....

ConcordeX - Master the Fuel Panel - YouTube

 

[Ray Proudfoot 8,954]

Concorde's performance is very dependent on air temperature. Some years ago I performed a series of descent tests inbound to JFK from Heathrow. The weather was set manually with zero wind and the only element changed was the air temperature.

Eight tests were flown with the temp ranging from ISA-20 to ISA+15. The decelleration prior to descent started at the same point - 57 DME from KENDA when the aircraft would have been at the same altitude - FL580.

The target altitude was 14,000ft at OWENZ as shown by the horizontal red line. The same engine settings were applied for each test. Here is the vertical profile for each test. With an ISA DEV of 0 OWENZ was reached at 14,000ft. The warmer the air the more rapid the descent. Cooler air results in a shallower descent.

With a ISA DEV of +15 the aircraft achieved 14,000ft well before OWENZ thereby burning more fuel by being lower for longer.

With a ISA DEV of -20 the aircraft was 9,000ft too high at OWENZ.

When determining your decel point the OAT has to be included in your calculation. A chart to help with this was supplied in the FSL Concorde manual. I'm sure this has been further refined with the forthcoming version.

 

[MarkW 1,491]

20 minutes ago, Rob_Ainscough said:

Any hints of sound?  My understanding is that the Concorde (as a passenger) was very loud.  Not sure if that translated into cockpit area?

Cheers, Rob.

I actually thought it was quiet for the pax?  I am sure Ray will know.

[MarkW 1,491]

Very interesting test data Ray.  I have been too high at OWENZ many times and having to do an extra long downwind for 31L to lose some altitude.

[Ray Proudfoot 8,954]

Sadly I never flew in it. Can’t imagine it was loud given the engines were right at the back with a huge delta wing providing some insulation.

In the flight deck it was loud until the nose and especially the visor were raised.

[Ray Proudfoot 8,954]

35 minutes ago, MarkW said:

Very interesting test data Ray.  I have been too high at OWENZ many times and having to do an extra long downwind for 31L to lose some altitude.

It tended to be the opposite for me Mark. Got down too quickly.

The tables were designed for the FSX version so in P3D there was a difference. I’m sure Andrew has brought them up to date together with an enhanced flight model.

The first phase down to Mach 1.5 shows the greatest variation depending on the air temperature.

[MachTwo 386]

1 hour ago, Ray Proudfoot said:

Sadly I never flew in it. Can’t imagine it was loud given the engines were right at the back with a huge delta wing providing some insulation.

It was certainly louder than others. The last few rows of seats were dubbed as 'Rocket Class' where you really could hear, smell and feel the four Olympus engines. Reverse thrust was very loud in the cabin - more so than the take-off. Presumably because the secondary nozzles deflected the sound forward. It was a noisy cabin anyway with huge amounts of ventilation keeping not only the cabin cool but primarily supplying air to the racks of computer equipment. What hit me most when walking onboard was the smell - it had a very distinctive smell of old aircraft and Jet A1 fuel. As with most supersonic aircraft, the things leaked fuel and hydraulic fluid when parked. Some more than others (Alpha Echo was particularly bad).

1 hour ago, Ray Proudfoot said:

I’m sure Andrew has brought them up to date together with an enhanced flight model.

Absolutely - we've been quite surprised at how the new model consistently hits the calculated deceleration profile - sometimes to within one nautical mile.

There was a question earlier in this thread about the relevance of the jet stream on Concorde. It did play a role - the strong eastbound jet over the North Atlantic between December and March would really speed up the flight times. The record of 2 hours 52 mins and 59 seconds from New York to London was achieved in early February '96 with the aid of strong tail winds. I think one of our guys did 2.53 the other week! We're starting to loose those conditions as we head into the end of March now. Last weekend there were warm upper air temperatures west of Ireland (ISA+10) which caused our test flights to not hit Mach 2 until 40 West (same ground speed, however, as the speed of sound is faster when it's warmer). It's all great fun - and not a magenta line in sight 😊

[B777ER 2,486]

Vatsim North Atlantic traffic is going to be quite interesting when this releases. I presume the NAT tracks are irrelevant? 

[SimeonWilbury 220]

35 minutes ago, B777ER said:

Vatsim North Atlantic traffic is going to be quite interesting when this releases. I presume the NAT tracks are irrelevant? 

I believe Concorde had it's own dedicated Atlantic routings that were pretty much permanent (I think they were part of the NAT system but I'm not sure, someone more well versed can correct me), the winds don't matter as much as Concorde's crusing altitude and there wasn't exactly much other traffic that high. Quite how that would translate to a busy Vatsim session one has perhaps yet to see!

Edited March 17, 2022 by SimeonWilbury

[MachTwo 386]

Yes, one fixed westbound track and two eastbound tracks (one was used as an overload track, primarily by Air France as it favoured their routing into CDG) - only in circumstances where the separation between two eastbound Concorde's was less than 12mins. 

OCA procedures were quite conventional - an initial SELCAL check followed by position reports. As the aircraft were never upgraded with datalink capabilities (ADS-B) - all of this was done over HF. 

[mazelda 124]

Lookin forwrd to this one, 

Hopefully bring back some of my early engineering career only ever worked her a couple of times when she flew into the regions. I played golf with one of her Captains a few times as well.

Always remember being told about ones of the drains in the rear cargo hold that told you the difference in pricing with aircraft parts and normal things.

The drain had a rubber ball made by dunlop in it that was coloured green and had a tiny yellow spot on it which back in the 70's cost aprox £16 as it was an aircraft approved part 

Back then you could go into most sports shops and purchase a squash ball made by dunlop that also had a little yellow spot, price about 50p.

I 've still got some unused damage charts as well knocking about.

It was a total disgrace what Airbus did to her in the end

[Ray Proudfoot 8,954]

1 hour ago, MachTwo said:

There was a question earlier in this thread about the relevance of the jet stream on Concorde. It did play a role - the strong eastbound jet over the North Atlantic between December and March would really speed up the flight times. The record of 2 hours 52 mins and 59 seconds from New York to London was achieved in early February '96 with the aid of strong tail winds.

This is interesting. I’ve known about this record for a long time but not the details of the flight. Mach 2 is only reached at FL500 but was there still a significant jet stream at that altitude? Did it continue to climb away from the strongest part of the jet stream?

Or did it stay lower to maximise the tail wind. So whilst the Mach speed may have been lower than Mach 2 the ground speed was twice the speed of sound or even greater?