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Speed problem?

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This Caravan is nice but if you are having problems with the <speed> it may be that the SPOILER is activated.Yes indeed, the Caravan 208B has a spoiler. In this Carenado model however, it is on by default (it seems). Note that it may depend onif you have a key defined for the Spoilers. Also you have no VISUAL clues that it is activated: no visuals in the VC or outside (look at far end of the wings).What you will feel however is that when you turn the Spoiler off (whatever the key it is set to) you will get your speed OK.Pierrenote: any quality control out there?

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Really? I got to check this, I haven't even considered it!

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Really? I got to check this, I haven't even considered it!
Yes, let us know Federico

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I don't see anything weird here, the spoiler button makes no difference. Are you sure about that?

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Can't confirm it either. Pressing that key makes no shred of difference for me.

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Can't confirm it either. Pressing that key makes no shred of difference for me.
I can confirm it. Did several tests: tried simple load of trekkies and switched to Carenado208b. Checked that my key pressed was not tied to something else and no it was fine. Checked that the spoiler key worked for a heavy. Worked.Reflew with the Carenado and it does it again: on a level flight at 4.5k I am doing 145k ias with the spoiler key it goes down to 85-90kts.Checked my version of the Caravan: version 1.0.0.0. Using Win7 Ult 64bit.Have no explanation yet.

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I can confirm it. Did several tests: tried simple load of trekkies and switched to Carenado208b. Checked that my key pressed was not tied to something else and no it was fine. Checked that the spoiler key worked for a heavy. Worked.Reflew with the Carenado and it does it again: on a level flight at 4.5k I am doing 145k ias with the spoiler key it goes down to 85-90kts.Checked my version of the Caravan: version 1.0.0.0. Using Win7 Ult 64bit.Have no explanation yet.
Hmmm, interesting. The first flight I ever took with the 208, I could barely get it up to 85-90 KIAS. Later that day, I loaded it from a different saved flight and suddenly the speeds were in the 130-140 range. If the first saved flight had spoilers activated, that would explain it. I'll have to do some more checking on this.

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I'm at the office so I can't check this, but is there a setting in the aircraft.cfg that enables the speed brakes? If so, try setting it to "0" and see if that makes a difference.

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Hi Gentlemen,I have activated and disactivated two times the spoiler command and got:At 4200 ft an IAS of 155 knots. ( 1787 Ft-Lbs, 1776 prop RPM, 754°C ITT )Is this normal ?.....Jean-Pierre

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Jean-Pierre,It's pretty hard to tell if that's correct. Try setting power so that ITT is at or below 740oC, and prop RPM at either 1900 or 1750. Also, tell us what the OAT is.

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Jean-Pierre,It's pretty hard to tell if that's correct. Try setting power so that ITT is at or below 740oC, and prop RPM at either 1900 or 1750. Also, tell us what the OAT is.
Hello Kurt,OAT 8°C (47/48 F), altitude: 3800 ft, ITT 741°C, prop RPM 1900, Tq 1633 ft-lbs, speed: 153 KIAS with 3 knots wind on the nose.Without wind more or less 156 KIASJean-Pierre

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Could it be that the spoiler command is activating the inertial seperator? hence the drop in airspeed? I'm not at home so I can't confirm. Just a thoughtI don't believe the 208 has spoilers per se, but it does in fact have, umm well I guess you could call them spoilerons. They only seem to be working in conjuntion with the ailerons.

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Could it be that the spoiler command is activating the inertial seperator? hence the drop in airspeed? I'm not at home so I can't confirm. Just a thoughtI don't believe the 208 has spoilers per se, but it does in fact have, umm well I guess you could call them spoilerons. They only seem to be working in conjuntion with the ailerons.
I believe you have something there Rick. Here is what the airplane geometry section says:spoiler_limit = 90.0spoiler_extension_time = 1.0spoilerons_available = 0aileron_to_spoileron_gain = 3min_ailerons_for_spoilerons = 5min_flaps_for_spoilerons = 0auto_spoiler_available = 0Now, let's go and see if I can determine if the intertial separator is activated?Pierre

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Jean-Pierre, that looks spot on.From the Cessna Grand Caravan PIH:"The airplane's flight control system (see Flight Control And TrimSystems figure) consists of conventional aileron, elevator and ruddercontrol surfaces and a pair of spoilers mounted above the outboardends of the flaps. The control surfaces are manually operated throughmechanical linkage using a control wheel for the ailerons, spoilers andelevator and rudder/brake pedals for the rudder. The wing spoilersimprove lateral control of the airplane at low speeds by disrupting liftover the appropriate flap. The spoilers are interconnected with theaileron system through a push-rod mounted to an arm on the aileronbell crank. Spoiler travel is proportional to aileron travel for ailerondeflections in excess of 5° up. The spoilers are retracted throughout theremainder of aileron travel. Aileron servo tabs provide reducedmaneuvering control wheel forces."We might be onto something here. This might be the source of our speed problem...then all that remains is the excessive ITT.

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Now, let's go and see if I can determine if the intertial separator is activated?
The inertial seperator is linked to the carb heat command, if that helps.

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Jean-Pierre, that looks spot on.From the Cessna Grand Caravan PIH:"The airplane's flight control system (see Flight Control And TrimSystems figure) consists of conventional aileron, elevator and ruddercontrol surfaces and a pair of spoilers mounted above the outboardends of the flaps. The control surfaces are manually operated throughmechanical linkage using a control wheel for the ailerons, spoilers andelevator and rudder/brake pedals for the rudder. The wing spoilersimprove lateral control of the airplane at low speeds by disrupting liftover the appropriate flap. The spoilers are interconnected with theaileron system through a push-rod mounted to an arm on the aileronbell crank. Spoiler travel is proportional to aileron travel for ailerondeflections in excess of 5° up. The spoilers are retracted throughout theremainder of aileron travel. Aileron servo tabs provide reducedmaneuvering control wheel forces."We might be onto something here. This might be the source of our speed problem...then all that remains is the excessive ITT.
This makes sense, as airliners use in-board spoilers for high speed operations (high speed ailerons) These take stress off the outer portion of the wing while at cruise speeds during turns. And looking at the caravan and it's purpose as a short field/low speed plane, it makes perfect sense to utilize an out-board spoiler type system in conjunction with the ailerons to provide added agility at lower speeds. IE. setting up for a short final with a turn on short base!

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Here's another bit of anecdotal corroboration for ya: I was leaving Walter Sutton's farm last night, doing some Caravan sightseeing and testing the new air file mods. Right after takeoff, I noticed the plane was struggling to get up to 80KIAS, so I leveled out. It wouldn't go any faster, even at full power and prop. Then I remembered the "/" key (spoilers), and hit it. Instantly, the plane began to surge ahead, quickly reaching normal performance. What I need is some visual way to tell if the spoilers are extended. I'm thinking about just setting a key in FSUIPC that retracts them, and making that keypress part of my preflight setup.

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That's really strange. I never experienced severe speed problems like that and the spoiler button (doesn't matter if I take the keyboard shortcut or the assigned button on my throttle) doesn't do anything.

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That's really strange. I never experienced severe speed problems like that and the spoiler button (doesn't matter if I take the keyboard shortcut or the assigned button on my throttle) doesn't do anything.
No problem here, either. Maybe depends on exactly how you load the aircraft.

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No problem here, either. Maybe depends on exactly how you load the aircraft.
I'm thinking that, too. It's only the second time I've had this speed limitation problem, but it happened when starting from two different saved flights.

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I load my flights by selecting the aircraft of my choice and the airport directly from the main menu. I don't load another aircraft first. Since some settings can bleed through from the default savegame, I made my default savegame a completely cold & dark default Cessna 172.

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Here's another bit of anecdotal corroboration for ya: I was leaving Walter Sutton's farm last night, doing some Caravan sightseeing and testing the new air file mods. Right after takeoff, I noticed the plane was struggling to get up to 80KIAS, so I leveled out. It wouldn't go any faster, even at full power and prop. Then I remembered the "/" key (spoilers), and hit it. Instantly, the plane began to surge ahead, quickly reaching normal performance. What I need is some visual way to tell if the spoilers are extended. I'm thinking about just setting a key in FSUIPC that retracts them, and making that keypress part of my preflight setup.
Bill, as I'm working on the air and cfg files, I noticed that 80 knots is the "low speed theory" boundary. Below 80 knots the plane is speed unstable, this means that to accelerate you have to lower your nose. Also called the back of the drag curve, below Vmd (velocity of minimum drag) if you just increase the power you'll stall. As you're in the takeoff phase, you have your maximum power in, so the only way out is lower your nose, pass 85 knots, raise the flaps and you should be ok.I don't know how well FS creates this low speed flying thing, but the parameter is there, so...Cheers

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