The advantages of engine configurations...

[Yeoman_dai]

Another one for the grownups here!

Everyone knows that the Lightning was one hellva fast mover, but my question is this...

Did it gain any specific advantage from having its engines mounted one on top of the other, as opposed to side my side like every other twin engined aircraft i've ever seen?

What would the specific advantages/disadvantages of the different engine layouts?


Thanks in advance.

[stickmonkeytamer]

Stacking the engines vertically (staggering them to avoid too much weight aft, with the lower engine forward of the upper) helped to minimise drag, effectively tucking them behind the cockpit, fed from air through the nose, achieved minimum frontal area. This effectively gave twice the thrust of its contemporaries for an increase in frontal area of only 50%.

SMT

[Ali Barber]

No Assymetric yaw problems, but did once have an exciting take off when the top burner did not light. Eventually slammed the stick forward and back to bounce the nose wheel off the ground as all 3 wheels were still firmly planted at 170 kts.

The top engine was further back so that the pilot had somewhere to sit was what I was told!!

After one Lightning skimmed the rooftops of Grimsby before ejecting due to a stuck elevator (and the almost landing of the DC-10 at Sioux City), we used to attempt recoveries using rudder and differential throttle to control the pitch. Nobody had to do it for real, but I was at Binbrook when a Jet Provost landed using the trim tab for pitch control as his elevators had jammed.

[Pontius Navigator]

It might also have had some benefit of area-rule.

The Buccaneer and F106 both had waisted fuselages to compensate for the inncreased frontal area of the wings. By mounting the engines vertically and later adding a ventral tank, a similar gradual increase in cross section could be obtained but retaining the thin wing for supersonic flight.

Just a thought.

[Notmyreallogin]

Biggest disadvantage as I understand it was fire. If the bottom engine burned, it set fire to the top one, if the top engine burned, molten metal would find its way to the bottome one.

Sub opitmal, I would suggest. However, I'd fly one if I could!!!

NMRL

[lightningmate]

Regardless of orientation, engines mounted in close proximity are always at risk of sustaining collateral damage should an adjacent engine fail catastrophically. There being numerous examples over the years. Hence, engine design seeks to contain failures - but not easy when heavy, rapidly rotating lumps of engine decide to go walkabout..

If I recall correctly, John Ward did recover a Lightning back to Akrotiri during 56 Sqn's tenure with limited, if not total, lack of conventional longitudinal control and was awarded an AFC to boot.

lm

[Pontius Navigator]

If I recall correctly, John Ward did recover a Lightning back to Akrotiri during 56 Sqn's tenure with limited, if not total, lack of conventional longitudinal control and was awarded an AFC to boot.

lm

I'll ask him when I see him.

There was one period, around 1972, that 56 dumped one aircraft per month in the bay. Then, when they were in UK for an MPC, the relief sqn doing an APC dumped one of their jets there too. Fortunately none of the crashes resulted in any fatalities or injuries.

The ditchings may have been premediated as Akrotiri had only one runway which was clearly of more strategic importance than a Lightning.

At the time the magazine scribe for IX Sqn made an injudicious comment in the station mag until someone whispered in his ear that the next one might be fatal. IIRC there were no fatalities. The scribe retired as an AVM but is still closely involved in scribbing. [The dangers of teaching pilots how to write.]

PS, lost a school chum on 74 trying to get the crippled jet back to Tengah and avoid spearing into a kampong.

[Gainesy]

There was one period, around 1972, that 56 dumped one aircraft per month in the bay.

They were trying to build a causeway to Beirut, (it was nice then).
Actually, I only recall two or three doing a spurlash test.

[ORAC]

Area rule, room for the pilot, drag....

All right, I give up, which one applied to the Short Sperrin..... :cool:

http://prototypes.free.fr/sperrin/images/sperrin_03.jpg

[Wader2]

ORAC, actually I think that looks rather nice. It also appears to have 2 different engines.

[ORAC]

That's a later Mod to fit the Gyron for trials, the original had 2 avons, same as the Lightning. Short Sperrin - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Short_Sperrin) - Wikipedia

This is a shot with the original engines, a bit more slab sided...

http://www.aviastar.org/pictures/england/short_sperrin.jpg

[BEagle]

It looks as thought the designer forgot he wasn't still designing flying boats until he'd done the nose....

Actually, I think it looks plug ugly!

[Pontius Navigator]

Looks like they used the tail from Vickers and the wings from de Haviland but used a spare Sunderland rig.

[Rigga]

Yep!
A nasty accident - rear end smash - of a Valetta into a Nimrod, ending up in a broken sunderland.
Who was it that said "if it looked right...."

[Chancros]

One disadvantage of the Lightning was that the engine config left little room for fuel. So they crammed it in where they could, including inside the flaps (!). This meant that there were many incidents involving fuel leaks, and a high maintainence load to try to limit them.

[charliegolf]

Did i read somewhere that if the firebottle on the Lightning needed changing, the engine had to come out?

CG

[Rigga]

Must've been similar to Hunters then - Tail off and engine out at the drop of a hat...
And the Harrier - Wings off at the drop of a pin (or nut, or bolt...)