The Night Mail

[Dave Hunt]

The ability of an aircraft to fly and manoeuvre depends on what is called the indicated airspeed (IAS) which is the speed that is registered on the airspeed indicator and is effectively a measure of the amount of air flowing into the pitot head and is therefore affected by the outside air density. Thus, as the aircraft climbs and the air density decreases, for a given speed across the ground the IAS will reduce; alternatively for a given IAS the true air speed (TAS) will increase. The drag on the airframe is also affected by the air density so at high altitude at a low IAS the drag, and therefore the amount of power required, will be low but the TAS, and therefore speed over the ground, will be high. That is basically why aircraft cruise at high altitude. There are lots of complicating factors, however, one of which is that the power produced by the engines will also reduce at altitude as the amount of air available for combustion decreases as the outside air density decreases and as the Mach number (the speed relative to the local speed of sound, also dependent on air density) approaches Mach 1 funny things happen due mainly to shock wave generation and the drag rises, as does strain on the airframe. Thus, as well as a never exceed IAS for a particular aircraft, there is also, for most types, a never exceed Mach number. The bottom line as far as the U2/TR1 discussion is concerned is that the best cruise speed at very high altitude is at an IAS that is quite close to stall speed, which will decrease as fuel is burned and the all up weight decreases commensurately, but is also close to the limiting Mach number. This was well illustrated during test flying of the prototype B-47 when maximum operating altitude was being explored and the pilots inadvertently got into a situation where they were virtually at both stalling IAS but limiting Mach number. The problem was how to descend without exceeding the latter but not allowing the IAS to get too low such that control was lost and it took a long time and some very careful handling to get down. At low level, the margin between the two is large, however, and before limiting Mach number is reached the aircraft will generally reach its limiting IAS. In the case of the U2/TR1 the margin at low level, although not as great as with most aircraft because of the large wingspan, is quite adequate. And as a matter of interest, 65,000 ft is nowhere near the maximum altitude of a TR1.

 

The above is actually a very simplified version of the matter and I apologise to those who have a knowledge of aerodynamics but I have tried to give an understanding without the complications.

 

As far as the Lightning is concerned, I have never heard of any reason why it shouldn't fly, theoretical or otherwise, and the fact that I am able to type this is testament to the fact that it can, in fact, fly very well.

 

I've probably missed some of the points raised earlier but that's enough for now.

 

TTFN 

 

Dave   

[Dave Hunt]

6 hours ago, Happy Hippo said:

I suspect the runway would be kept clear until the aircraft has safely departed and then the bits that fell off could be recovered.

 

I believe a chase car is deployed during the landing with a second pilot in the car calling the last few feet of altitude, so the aircraft can be stalled onto the runway from about 2 feet off the ground. It's very technical and DH would be able to describe all the ins and outs far better than I ever could.

 

 

That's close enough.

 

Dave

[PupCam]

6 hours ago, Tony_S said:

Sounds like a Thunderbirds episode. 

 

"Fireflash, lift port wing!"  

[Compound2632]

Covid in my right arm and flu in my left today, so I'm one more for the vaccination statistics. There are some interesting charts in this Grauniad article, especially the revelation that more elderly Scots have been vaccinated than were thought to exist (also in what we must conclude to be the wisest age group in England). The regional and ethnic variations are, to my mind, particularly disturbing.

[Florence Locomotive Works]

Gentlemen, I have seen the error of my ways.

 

I humbly beseech those of you who model that great bastion of G R E E N known as the GWR to accept me back into your ranks, albeit with only one currently non working pannier.

 

I am at the moment reading I.K. Brunel’s biography, and the temptation to paint my engine who is named after him in GWR livery is to great. I will only be painting the frames though. I’m thinking India red. Does anybody know what colors go together to create this?

 

Douglas

[AndyID]

1 hour ago, Florence Locomotive Works said:

 I’m thinking India red. Does anybody know what colors go together to create this?

 

Wikipedia is your friend.

[polybear]

2 hours ago, Florence Locomotive Works said:

Gentlemen, I have seen the error of my ways.

 

I humbly beseech those of you who model that great bastion of G R E E N known as the GWR to accept me back into your ranks, albeit with only one currently non working pannier.

 

 

Fear is the path to the dark side … fear leads to anger …  anger leads to hate … hate leads to suffering.......

[AndyID]

I see Toyota is now selling a proper electric car - powered by a hydrogen fuel cell. I've been waiting for this for sixty years and I'd buy one in a heartbeat if I could. Unfortunately they are only available in California for now.

 

(Having lit the blue touch paper I shall now retire.)

[jamie92208]

30 minutes ago, AndyID said:

I

(Having lit the blue touch paper I shall now retire.)

That should certainly make it go with a bang.

 

Jamie

[AndyID]

1 minute ago, jamie92208 said:

That should certainly make it go with a bang.

 

Jamie

 

I didn't retire just yet

 

Hydrogen has had a bad name ever since the Hindenburg disaster (which was bad but nowhere near as bad as many airliner disasters since, and it did not explode). Hydrogen is really no more dangerous than the propane that you use in your grill. In many respects it's actually a lot less dangerous than petrol. You can put a lit taper into hydrogen and the hydrogen will extinguish the flame. Like all flammable gasses, unless it's mixed with oxygen, hydrogen is quite harmless.

[Tony_S]

1 hour ago, AndyID said:

I see Toyota is now selling a proper electric car - powered by a hydrogen fuel cell. I've been waiting for this for sixty years and I'd buy one in a heartbeat if I could. Unfortunately they are only available in California for now.

 

(Having lit the blue touch paper I shall now retire.)

Is that the Toyota Mirai?. I read a review of them here in the UK.  Apparently nice car but only 8 hydrogen fuel stations in the country made it a bit inconvenient. Apparently not a problem in Germany or Japan.  Hyundai do a hydrogen car too, looks more like an SUV than the Toyota design. 

[AndyID]

Just now, Tony_S said:

Is that the Toyota Mirai?. I read a review of them here in the UK.  Apparently nice car but only 8 hydrogen fuel stations in the country made it a bit inconvenient. Apparently not a problem in Germany or Japan.  Hyundai do a hydrogen car too, looks more like an SUV than the Toyota design. 

 

Yes, that's the one Tony. At the moment it's only available in California in the US where there do seem to be quite a lot of stations. Unfortunately it's not likely there will be too many around here anytime soon.

 

If you haven't already guessed, I'm a heretic   Batteries are a good interim solution for short distances but they are NBG for long-haul and heavy transport. The story is the battery materials will be recycled but TBH I'm just not buying it. Synthesizing hydrogen from electrical energy and water may be expensive but it's a fantastic way to store energy.

[SM42]

Panniers on the Lickey to hydrogen cars via a quick lesson in flight in a couple of pages. 

TNM lives up to its reputation as a wild ride yet again. 

 

I have come to the conclusion that this flying lark is  complicated.

 

In Covid news. 

Bad night last night, very shivery, but feelng much better today so far.

 

If Mrs SM42 gets out of tidying mode ( there must be a switch or something somewhere) I may try to do a bit if wagonery today.

I am not hopeful though

 

Best all

 

Andy

[Happy Hippo]

11 hours ago, Dave Hunt said:

The ability of an aircraft to fly and manoeuvre depends on what is called the indicated airspeed (IAS) which is the speed that is registered on the airspeed indicator and is effectively a measure of the amount of air flowing into the pitot head and is therefore affected by the outside air density. Thus, as the aircraft climbs and the air density decreases, for a given speed across the ground the IAS will reduce; alternatively for a given IAS the true air speed (TAS) will increase. The drag on the airframe is also affected by the air density so at high altitude at a low IAS the drag, and therefore the amount of power required, will be low but the TAS, and therefore speed over the ground, will be high. That is basically why aircraft cruise at high altitude. There are lots of complicating factors, however, one of which is that the power produced by the engines will also reduce at altitude as the amount of air available for combustion decreases as the outside air density decreases and as the Mach number (the speed relative to the local speed of sound, also dependent on air density) approaches Mach 1 funny things happen due mainly to shock wave generation and the drag rises, as does strain on the airframe. Thus, as well as a never exceed IAS for a particular aircraft, there is also, for most types, a never exceed Mach number. The bottom line as far as the U2/TR1 discussion is concerned is that the best cruise speed at very high altitude is at an IAS that is quite close to stall speed, which will decrease as fuel is burned and the all up weight decreases commensurately, but is also close to the limiting Mach number. This was well illustrated during test flying of the prototype B-47 when maximum operating altitude was being explored and the pilots inadvertently got into a situation where they were virtually at both stalling IAS but limiting Mach number. The problem was how to descend without exceeding the latter but not allowing the IAS to get too low such that control was lost and it took a long time and some very careful handling to get down. At low level, the margin between the two is large, however, and before limiting Mach number is reached the aircraft will generally reach its limiting IAS. In the case of the U2/TR1 the margin at low level, although not as great as with most aircraft because of the large wingspan, is quite adequate. And as a matter of interest, 65,000 ft is nowhere near the maximum altitude of a TR1.

 

The above is actually a very simplified version of the matter and I apologise to those who have a knowledge of aerodynamics but I have tried to give an understanding without the complications.

 

As far as the Lightning is concerned, I have never heard of any reason why it shouldn't fly, theoretical or otherwise, and the fact that I am able to type this is testament to the fact that it can, in fact, fly very well.

 

I've probably missed some of the points raised earlier but that's enough for now.

 

TTFN 

 

Dave   

Told you all it was more interesting than Midland barrows v Pannier tanks.

 

Less exciting is my requirement this morning to enter the attic of the Hippodrome in order to recover the pallets containing the Christmas decorations.

 

I'd hoped that my contribution to the festive decoration had finished when I put up the outside decorative lights.

 

This is a quick job as they are carefully coiled and tested, so they are unrolled and placed onto the permanent hooks on the wall.  It's all over in about 15 minutes which includes a long tea break.

 

Interior decoration is slightly more complex and annoying:

 

I have to remove all my modelling stuff from the garden room table, windowsills, and floor in order for the place to be cleaned prior to the erection of 'the tree'.  Then a fighting withdrawal is made through the rest of the downstairs as the boxes of decorations are unpacked and push forward until no part of the downstairs is free from the twinkling of lights glitter and tinsel (and that's just my smoking jacket).

 

The final act is to switch the chime on the doorbell from the usual 'Ding ' to 'Jingle Bells' (although this is only done to appease the grandchildren).

 

However the Christmas spirit is then there in name only, as I am forbidden from quaffing sherry and stuffing my emaciated body with Stollen, mince pies or shortbread biscuits until much later in the month.

[Happy Hippo]

5 hours ago, Florence Locomotive Works said:

Gentlemen, I have seen the error of my ways.

 

I humbly beseech those of you who model that great bastion of G R E E N known as the GWR to accept me back into your ranks, albeit with only one currently non working pannier.

 

I am at the moment reading I.K. Brunel’s biography, and the temptation to paint my engine who is named after him in GWR livery is to great. I will only be painting the frames though. I’m thinking India red. Does anybody know what colors go together to create this?

 

Douglas

I am no expert on the liveries of the GWR, and would suggest that you might look here for guidance:

 

http://www.gwr.org.uk/liveries.html

 

This might explain why I have a liking for black pannier tanks.

[jamie92208]

48 minutes ago, AndyID said:

 

Yes, that's the one Tony. At the moment it's only available in California in the US where there do seem to be quite a lot of stations. Unfortunately it's not likely there will be too many around here anytime soon.

 

If you haven't already guessed, I'm a heretic   Batteries are a good interim solution for short distances but they are NBG for long-haul and heavy transport. The story is the battery materials will be recycled but TBH I'm just not buying it. Synthesizing hydrogen from electrical energy and water may be expensive but it's a fantastic way to store energy.

I am also a heretic and think that in our situation with long drives (20 to 40 miles) to supermarkets, hospitals and of course railway lines, a diesel is probably the best option in the long term.  Beth's Clio, has a stop start system to avoud fumes in urban traffic jams. These are non existant for over 99% of our journeys but her battery costs twice as much as for my ancient Volvo.  I also share your concern about the total life cycle costs of battery and hybrid vehicles in our situation.

 

Jamie

Edited December 8, 2021 by jamie92208

[Winslow Boy]

2 hours ago, AndyID said:

 

I didn't retire just yet

 

Hydrogen has had a bad name ever since the Hindenburg disaster (which was bad but nowhere near as bad as many airliner disasters since, and it did not explode). Hydrogen is really no more dangerous than the propane that you use in your grill. In many respects it's actually a lot less dangerous than petrol. You can put a lit taper into hydrogen and the hydrogen will extinguish the flame. Like all flammable gasses, unless it's mixed with oxygen, hydrogen is quite harmless.

 

Its the last sentence that concerns me as 20 % of the earths atmosphere is I believe the aforesaid oxygen. So in order to be completely safe, which is what the numties will probably insist on, we would have to get rid of the oxygen. So my two part question is a). What do we do with it and b) how do we breath. Answers on a postcard to: Genius answers for stupid questions, c/o The Hippodrome, North Hipposhire.

 

PS if a grumpy Hippo answers the door just tell him your delivering more Christmas decorations.

[Winslow Boy]

1 hour ago, SM42 said:

Panniers on the Lickey to hydrogen cars via a quick lesson in flight in a couple of pages. 

TNM lives up to its reputation as a wild ride yet again. 

 

I have come to the conclusion that this flying lark is  complicated.

 

In Covid news. 

Bad night last night, very shivery, but feelng much better today so far.

 

If Mrs SM42 gets out of tidying mode ( there must be a switch or something somewhere) I may try to do a bit if wagonery today.

I am not hopeful though

 

Best all

 

Andy

 

I find the best way is to wait until the hydrogen fuel cell runs down.

[Tony_S]

1 hour ago, SM42 said:

 

I have come to the conclusion that this flying lark is  complicated.

Having read all about various planes flying  yesterday for some reason I wondered about “can birds fly upside-down? “ I learnt a new word too, “whiffling”. 
 

[Happy Hippo]

5 minutes ago, Tony_S said:

 “whiffling”. 
 

Pre tail swing twitching....

 

And you know what comes next!

[J. S. Bach]

9 hours ago, Florence Locomotive Works said:

Gentlemen, I have seen the error of my ways. ...snip...

Douglas

You have decided to model the local BNSF!!!!

 

 

Edited December 8, 2021 by J. S. Bach
To do a minor edit, again.

[polybear]

6 hours ago, polybear said:

 

Fear is the path to the dark side … fear leads to anger …  anger leads to hate … hate leads to suffering.......

 

Now how does DH manage to leave both "like" and "agree" ratings?  Do we have two DH's by any chance?  Be scared, be very, very scared....

 

3 hours ago, Happy Hippo said:

Interior decoration is slightly more complex and annoying:

 

 

Bear's chrimbo decs will consist of plonking various cards around the conservatory as they arrive.  Job done. 

[laurenceb]

15 hours ago, Dave Hunt said:

The ability of an aircraft to fly and manoeuvre depends on what is called the indicated airspeed (IAS) which is the speed that is registered on the airspeed indicator and is effectively a measure of the amount of air flowing into the pitot head and is therefore affected by the outside air density. Thus, as the aircraft climbs and the air density decreases, for a given speed across the ground the IAS will reduce; alternatively for a given IAS the true air speed (TAS) will increase. The drag on the airframe is also affected by the air density so at high altitude at a low IAS the drag, and therefore the amount of power required, will be low but the TAS, and therefore speed over the ground, will be high. That is basically why aircraft cruise at high altitude. There are lots of complicating factors, however, one of which is that the power produced by the engines will also reduce at altitude as the amount of air available for combustion decreases as the outside air density decreases and as the Mach number (the speed relative to the local speed of sound, also dependent on air density) approaches Mach 1 funny things happen due mainly to shock wave generation and the drag rises, as does strain on the airframe. Thus, as well as a never exceed IAS for a particular aircraft, there is also, for most types, a never exceed Mach number. The bottom line as far as the U2/TR1 discussion is concerned is that the best cruise speed at very high altitude is at an IAS that is quite close to stall speed, which will decrease as fuel is burned and the all up weight decreases commensurately, but is also close to the limiting Mach number. This was well illustrated during test flying of the prototype B-47 when maximum operating altitude was being explored and the pilots inadvertently got into a situation where they were virtually at both stalling IAS but limiting Mach number. The problem was how to descend without exceeding the latter but not allowing the IAS to get too low such that control was lost and it took a long time and some very careful handling to get down. At low level, the margin between the two is large, however, and before limiting Mach number is reached the aircraft will generally reach its limiting IAS. In the case of the U2/TR1 the margin at low level, although not as great as with most aircraft because of the large wingspan, is quite adequate. And as a matter of interest, 65,000 ft is nowhere near the maximum altitude of a TR1.

 

The above is actually a very simplified version of the matter and I apologise to those who have a knowledge of aerodynamics but I have tried to give an understanding without the complications.

 

As far as the Lightning is concerned, I have never heard of any reason why it shouldn't fly, theoretical or otherwise, and the fact that I am able to type this is testament to the fact that it can, in fact, fly very well.

 

I've probably missed some of the points raised earlier but that's enough for now.

 

TTFN 

 

Dave   

Given that Taff Holden survived his flight in one the Lightning cannot have been too hard to fly. Which leads to another thought, what was said to pilots who did bend one after his flight?

[New Haven Neil]

27 minutes ago, J. S. Bach said:

You have decided to mode the local BNSF!!!!

 

 

 

BigNewSantaFe? Nah, only one true US Railroad worth modelling.....

 

 

 

[TheQ]

of course  be fore the Lightening there was the Canberra in 1957 one of those topped 70,000 feet.... with a little help from a rocket after 44,000 feet..

Then the Americans had the below heavily modified Canberra, effectively the prototype for the U2, used for a similar mission until the U2 arrived

 

Nasa are still using 3  modified Canberras  

Edited December 8, 2021 by TheQ