Posts by user "Shaggy Sheep Driver" [Posts: 67 Total up-votes: 0 Page: 2 of 4]¶

If I may be permitted to tread drift a bit re engine rotation effects: prop-driven aircraft suffer a range of unpleasant effects that jets don't. Not least is the prop slipstream effect; the propwash spirals around the aeroplane and pushes on the fin inducing a turn. This is at its worst at take off, with no slipstream and high power; even our Chipmunk needs a bootful of left rudder to keep straight when full power is applied at the start of the take-off roll. A really powerful aeroplane like a Spitfire cannot use full power until there is sufficient airspeed to make the rudder effective enough to keep straight; one reason why later Spits had contra-rotating props.

Then, for a taildragger like the Chippy, there's the 'assymetric blade effect' or 'p' factor, where with the tail down the down-going prop blade produces more thrust than the up-going one. And the engine torque effect particularly noticable on soft runways with powerful aeroplane where one mainwheel tyre is pushed into the ground with more force than the other, and finally the gyroscopic swing induced in a taildragger as the tail comes up and the prop disc is tilted to the vertical.

All of these effects are cumulative, and it's one reason why tail-wheel prop pilots learn to use their feet! All are obviated by contra-rotating props or, for twins, 'handed' engines which rotate in opoosite directions to each other.

When I had a share in a Yak52 I used to use the 'engine torque effect' to steer the aeroplane on Barton's muddy winter surface; using the conventional method (braking the appropriate mainwheel; the nosewheel was free-castoring) didn't work as the (quite thin) wheel would just lock and slide along, not inducing a change of direction at all. But whack on a fistful of Vendeneyef and 360hp would dig the right main into the ground and she'd turn right. Pull the power off suddenly and the left main would dig in, turning her left. Worked a treat!

I though delat wings didn't stall provided there was sufficient power to overcome the drag (thought at ludicrously high AoA that power requirement would be ginormouse!)?

About 18 tons an hour I think. More like 80 tons an hour at take-off! The higher and faster she went, the more efficient she became!

Shirley the aft CG research for lower cruise drag could equally be done with conventional Concorde controls? Why is it associated only with sidestick control?

Concorde's min drag speed... was it 350kts or 400? I've seen both reported. Whichever it is, I understand it equates to approx M0.95 at 29,000 feet hence the subsonic cruise being generally flown at that relatively low altitude.

SSD

I think the estimate is that the supersonic passenger requirement today could be satisfied by ten airframes. Hardly an attractive economic proposition for a manufacturer. If it were otherwise, Boeing and Airbus would be addressing that market with a state-of-the-art SST.

Dune Prune; as a pilot myself I long gave up on the film industry poaching on my patch! Life's too short.... the trangressions too numerous!

I'll echo M2's sentiment - stay around Dune and keep on posting. This is a friendly thread! And one that I have found extremely interesting.

I think M2dude had something to do with developing that 3/4 flag!

It's on the captain's side - no. 1.

Were there not 21 airframes built? The ones ChristiaanJ lists above, plus the one used for heat and stress cycling in the 'rig'?

Well if South Ken want to get rid of that 593, we'll give it a home in our building next to G-BOAC.

CJ - AC does indeed have all 4 engines in place and complete. I wouldn't want to drop an engine as that would make her an incomplete aeroplane, and actually you can clearly see the compressors deep inside the intakes during tours, which is nice. She'd look odd with one intake blanked off.

Ideally I'd like a sectioned 593 on display, as there's not a lot to see on the outside of a turbojet engine except the ancilliaries - and you can see those by opening the engine bay doors.

Someone's dreaming! It cannot be used as an engine according to the text (BA restriction) so it has value either as a museum exhibit or as scrap.

So either no monetary value (museum exhibit) or a few hundred pounds (scrap). Minus a few hundred pounds to transport it to the scrapyard!

I'd vote for M2 for writing that book.

I've spent hundreds of hours in AC's flight deck. The panels are grey!

And I think they were level at 60,000' and M2 in under 9 minutes from brakes off!

S'what I heard. I wasn't there mind, but it was on good authority....

Thanks for this, CliveL. Could you please explain 'expansion field over the wing '?
Thanks.

Also, how was the flow re-compressed at the tail? What is the aerodynamic explanation of this?

As the intakes produced shocks, what about other protruberances such a aerials and drain masts etc? Did these also produce (small) shocks?

Although the nose and tail shocks are 204 feet apart at the point they leave the aeroplane, I'd guess that they diverge away from each other with distance, so the further away you are from Concorde when they reach your ears, the longer the gap between the shocks.