HS748 Target Cruising Speed

[hobby]

The quoted cruising speed for a brand new 748 is 240kts TAS. Information on this forum indicates that the real aircraft are today operated at 220kts when cruising at up to 15,000ft. Is this TAS or IAS?

On the other hand is the best method, when operating with real weather downloaded from the web, I use ASv6, to fly the aircraft at up to 15,000ft with 14,200 RPM and fly at whatever cruising speed results from the engine settings and weather conditions?

When in commercial operation to a timetable at what cruising speed (TAS)is the timetable planned at?
I have found that it is very easy to lose time during a flight and while it is possible in fast military aircraft to deviate from a planned route by 'cutting corners' or increasing airspeed this is probably not possible when operating civil aircraft along the airways to a published timetable. So the speed used in producing a timetable is quite important. I would be interested to read of real world experience in this field.

For future reference I assume that cargo operations - postal flights etc are not so tightly tied into timetables but I have no knowledge of real world operations and would appreciate enlightenment.

[DaveB]

Unfortunately Hobby, the forum has been slower than a 3-legged dog race over the last 15mins and so I'm quite literally out of time but, to answer some of your questions..

Yes, 220kts is TAS in this case. We laboured a great deal over the speed issue and managed in the end to get some info off a guy who flies the 748. As you have said, crank on 14,200rpm.. set your fuel trim and whatever you see is what you'll get. Anywhere from around 180kias to around 210kias is about the norm in the cruise though this is very wx dependant.

I asked Brian Withers in our R&D section (as a by the by) how he would plan a journey from say Kinloss to Gander in the Nimrod and he said he'd have checked the distance then worked out how long it would have taken him TAS and fuelled up accordingly (sorry if I've misquoted you Brian but it's there or thereabouts I think)

As for cargo flights not being quite so tight as their pax equivallents.. I think they very much are. There are huge penalties to be paid by the operators if flights are not on time

ATB

DaveB :tab:

[Garry Russell]

Comment on cargo flights


There are major problems if the mail or newspapers (where they are airfreighted) are late. And other schedules have to run on time to make these time conscious ones operate

Arguable it is MORE critical for the mail and paper being a link in a long chain to be on time.

Garry

[Motormouse]

Comment on cargo flights


There are major problems if the mail or newspapers (where they are airfreighted) are late. And other schedules have to run on time to make these time conscious ones operate

Arguable it is MORE critical for the mail and paper being a link in a long chain to be on time.

Garry

Correct there Garry, the only time timings aren't so tight are with the ad hoc type of cargo charter, the "'ere mate can you fly this 5 tons of car parts to Stansted today?" sort of flight.

Longest 'hop' I did like that (in a Fokker 27) was Stansted to Constanta
with bits of metal for the Black Sea oil industry.

In the mail and parcelfreight (think fed-ex/ups) line, (and 360shed will agree here ) it wasn't unheard of to depart with only a part load if a.n other connecting flight or road/rail transport hadn't made the connection on time.

ttfn

Pete

[Garry Russell]

Hi Pete

Also some freight is not critical as in "if you can fit that on some time this week"

But the bulk is time concious

And of course there is a whole network of before ten am tomorrow type deliveries and those not involved in that best keep their schedules tight or any slacking could lose custom to them even if a premium rate applies.

We live in a world where it needs to be here yesterday amd a lot of businesses now keep minimal or no stock. That is based purely on within four hours delivery.

No time for any freight outfit to slack nowdays

Ease of handling and speedy delivery in a way is the selling point of freight.

Garry

[Motormouse]

Hi Pete

And of course there is a whole network of before ten am tomorrow type deliveries Garry

At risk of hijacking another thread

Yep. been there done that, worst are the VIP (Valuable,Imperative,Perishable) cargo's, worst load I ever flew with was 2 tons of Spider crabs, in sea water 'holding buckets' from Shannon
to Paris, the stink pervaded the whole plane for ever after that.

Most valuable was probably the 2ft sq chest of 'krugerrands', that went from somewhere to Amsterdam.

Silliest use of a cargo plane had to be the large 'jiffy' type bag
of car engine valve spring collets we had to collect from Valencia and return to Cardiff (for the Fords factory at Bridgend).

ah...days gone by....

ttfn

Pete

[Chris Trott]

Here in the US, a large portion of the ad-hoc cargo work East of the Mississippi is for the automotive industry, flying all sorts of parts between factories and assembly plants. It's not used as a primary form of transportation for the most part, but with them all operating on a "just in time" schedule, air transportation allows factories to shutdown the line for maintenance and then rapidly ship the initial batches of parts to their needed location much more rapidly than trucks to allow them to not fall behind on production. Once these batches have reached the plant (just in time to prevent a shutdown) it will keep the plant operating long enough for the first truck shipments to arrive and resume normal deliveries. They also hire air transport to get parts racks back to the factory when they're running short due to a delay in the trucks arriving back from the plant.

I've been part of flying a few odd items in the past though. Flew some classified cargo for the Navy once too. Was kinda odd too. All we had was dimensions and weight of the cargo, where to pick it up and drop it off, and a darned good payment to fly it. Aircrew reported that the cargo was in an unmarked plastic box tied to a pallet that was then strapped to a "cookie sheet" so we could roll it into the middle of the plane and lock it in place. Only took up about half of the cookie sheet, but it was very heavy (9000+ pounds) so we were pretty sure it was part of a submarine's drivetrain (came from an airport near a sub base and went to GE).

[DaveB]

As long as you don't glow in the dark now Chris.. that's the important thing

Jolly interesting thread chaps

ATB

DaveB :tab:

[hobby]

This thread has produced some very interesting and informative answers.

Thanks to all who have answered so far. I do hope that other real world pilots from different parts of the world will also contribute.

Spider crabs (2Tons) - hope none escaped and a jiffy bag of springs! I wonder what the Captain's facial expression was when he was handed that very small package. Kruger Rands must have been heavy!!

Rick has kindly designed the 748 to operate as either a cargo or passenger aircraft and also capable of using the FScargo program so proper virtual flight planning can now take place.

[Garry Russell]

Spider crabs :shock:

There must have ben a bit of a nip in the air! :roll:

Garry