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FedeSuper10

Problem with spoilers

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Hi, i'm having issues with my spoilers on the DC-8:

i can't extend its during flight, for example, during the descent to the destination airport... i opened the operational manual and i saw that the hydraulic system that manage the spoilers is shared with the one of the landing gear, so when the landing gear is retracted, the spoilers doesn't recive any hydraulic pressure, but i also saw that they've a switch that can override this situation, so during a test flight i tried to set the switch in override mode, hydraulic pressure increased till 3000psi as the operational manual says, and then i tryed to deploy its (i were at 185 knots stable at 4000 feet), but nothing appened, when pressing the "ù key" used in FSX to deploy spoilers, they don't move, i can just arm them... There is something i'm missing or forgotting? 

Thank you in advance

 

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The spoilers on DC-8 are only working in flight with GEAR-DOWN to assist in roll-mode and then deploy in landing......

 

If You will reduce speed air You are supposed to use ENG 2+3 reversers and they make a lot of noise and upset pax but tht's the way to do it......

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AAC47 is correct.  By, design they won't work in the air to slow you down.  They only work on touch down as spoilers.  They will function as spoilerons in the air, but only with the landing gear down.

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So the only way to reduce speed during descents is to use the reverser of the engines? I never thought that was a possible to do that!

But i will have to do it, i'm tyred of program my descents 50/70nm prior of the TOD, either with low vertical speed such -1500fpm and the throttles in idle the speed increases so fastly! 

Thank you guys, i will test it tomorrow...

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1 hour ago, FedeSuper10 said:

So the only way to reduce speed during descents is to use the reverser of the engines? I never thought that was a possible to do that!

But i will have to do it, i'm tyred of program my descents 50/70nm prior of the TOD, either with low vertical speed such -1500fpm and the throttles in idle the speed increases so fastly! 

Thank you guys, i will test it tomorrow...

Try to descend maintaining idle thrust and an indicated speed around 300 knots. Usually the plane will fly 2.5 to 3 nautical miles per 1000 feet of altitude lost. The vertical speed should settle around 5 times the groundspeed. For example, if you're descending with a groundspeed of 480 kt, your vertical speed should be 480x5=2400 ft/min in order to maintain a 3 nm to 1000 ft of descent gradient. 

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Ok, i just tested the reverse thrust of engines 2 and 3 during flight, it works! they gave you a very poor deceleration, but at least it works and help a bit... I understood thanks to your comments guys, and some internet researches, that the plane has only ground spoilers that can assume 2 positions, full up, and full down, and can only be engaged with the landing gear deployed... so the reverser takes the taks of the modern speed brakes. 

Regarding the post of @PMSoares, thank you for the advice! I'm just flying a leg from Dubai International to Rome Fiumicino on IVAO, and i will test this calculation to help me in my descent. Thank you all again guys!

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