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Twin Otter X: open issues


Mathijs Kok
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There are 4 knobs:

left outer

left inner

right outer

right inner

the inner knobs are controlled by placing the mouse over the midst of the knobs and the outer by placing the mouse beside the knobs. Changing the numbers is done with the mousewheel.

You might need to zoom a bit in on tha ADF radio.

Finn "wothan" Jacobsen

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Would be great , thanks : )

Hi there. Sorry for the delay. I just completed my tests and converted every single texture down from 32bit to DXT5 that are needed for a livery. Fuse textures and the fallbacks would normally be 70+MB textures, now I've only 22MB. The result for me is much much faster loading time for the textures and indeed a slightly better framerate too, not much but about 2fps for me on top of the great framerate the Twotter turns in anyway. And it stays razor sharp not matter what I do. But the best thing is the much faster loading time. Switching into VC for the first no longer causes some 5-6 seconds wait for me till every texture is loaded, it only takes a mere 2-3 seconds now.

I'll send you a PM how you can do that yourself. Ok?

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Hi there. Sorry for the delay. I just completed my tests and converted every single texture down from 32bit to DXT5 that are needed for a livery. Fuse textures and the fallbacks would normally be 70+MB textures, now I've only 22MB. The result for me is much much faster loading time for the textures and indeed a slightly better framerate too, not much but about 2fps for me on top of the great framerate the Twotter turns in anyway. And it stays razor sharp not matter what I do. But the best thing is the much faster loading time. Switching into VC for the first no longer causes some 5-6 seconds wait for me till every texture is loaded, it only takes a mere 2-3 seconds now.

I'll send you a PM how you can do that yourself. Ok?

We disabled PM's on our forum because it caused huge amounts of private support posts that were answered many times on the forum.

But I have been trying this as well and indeed, if you got a serious graphics card DXT5 seems very possible. The decompression on the GPU seems faster than is done on CPU, So this will work fine for some people, but not for all (can you hear our support staff growing in the back?)

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Hey this is my first post. :P

Sorry, but I haven't the energy to read though all 7 pages so if this one is already brought to your attention the just ignore.

1. You can talk to ATC with the radios off.

Thanks

Ben

Welcome Ben!

Radio's off means most likely that the avionics bus is still on and FSX feels that means coms is possible. If I recall correctly the Wright Flyer in FS2004 was able to talk to ATC to ask for a clearance.

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Welcome Ben!

Radio's off means most likely that the avionics bus is still on and FSX feels that means coms is possible. If I recall correctly the Wright Flyer in FS2004 was able to talk to ATC to ask for a clearance.

Okay sure, it's just that on a few other add-ons I have you can't if the radio's are switched off.

By the way say thanks to the team for a excellent add-on. I'm really enjoying the Twotter. 8)

Ben

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We disabled PM's on our forum because it caused huge amounts of private support posts that were answered many times on the forum.

But I have been trying this as well and indeed, if you got a serious graphics card DXT5 seems very possible. The decompression on the GPU seems faster than is done on CPU, So this will work fine for some people, but not for all (can you hear our support staff growing in the back?)

I noticed the lack of PM too, no problem. And I don't have what you would consider a "serious" GPU. Quite the opposite is the case. I'm flying FSX on my subnotebook which has a NVidia 7400Go. That one has only 64MB RAM dedicated and a huge amount shared of the main system RAM. For me bringing down the texture size using DXT5 helps a lot because it takes a lot of load of the graphics RAM. I don't think that DXT-decompression eats up a lot of the GPU power. If so, it takes less than I gain by DXT-compression and the result is still positive.

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Thanks Private-Cowboy for posting the item about VC texture loading. I've been going nuts over this. I have a new clean system build with an E8400 and 8800 GT and (everything latest SPx and no OC). Most of the time - but not all of the time - when I load the VC from some other view, I wind up with a black VC that has to be refreshed - which typically takes about a second or two. I have been watching and reading but nobody else mentioned this so I was sure it was my problem. And maybe in part it still is (never said I was a good FS tuner).

But all that said... if you're able to go from 5-6 seconds to 1 or so by using the DXT5 textures, then surely there is some avenue for improvement on my end (as well as others).

BTW Mathis - a great addition to my hangar. I'm still on a learning curve with VC only, but the "modern" 2D stuff provides some salve. :)

Cheers!

GMark@KLUK (moved from KMGY)

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Hi Mathijs,

I am back to you with another stupid idea:

Will it be possible to have, as an OPTION, a set of high definition interior texture (could be DXT5 to limit the weight).

We spend normally 99% of our flying time in the cockpit don't we, it would then seem very reasonnable to accept lighter textures outside but better inside (same logic as for aircraft animations that you choose to cut down). This suggestion is also valid for the Beaver.

Best regards

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Hi,

I have another minor issue related to Aux Fuel Pump versus annunciator panel.

in my version of DHC-6, with the annunciator panel lights off, the fuel pump sound is on. when I turn the fuel pump sound off, the lights on the annunciator panel come on.

I believe they should be in sync - pumps on, lights on, and conversely, all off at the same time. Is this correct?

Great plane - I am logging lots of hours.

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Hi! My first post here :)

Just want to thank Aerosoft for a wounderful airplane! Cant wait to the Wideroe paint comes out! Truly amazing :)

But I`v got a little problem with the sounds. When I startup I`m not getting the feathering sound, just some rumbling noise. Have the same problem when shutdown, just some rumbling. I dont know if its my sound-card or something? Also the sound gets stuck at high RPM on default airplanes, not on the Twotter, if its any help. If you would help me out it would be lovely!

Best Regards Johan Holmseth

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Hi all, also my first post here.

First off; Thanks for making the Twotter, truly a real great addon plane! I have been waiting for this one since the word came up on this forum. Now I already have logged many hours in this legend of a plane. Its great to fly, especially here in Norway, with lots of relatively short runways.

There seem to be a few details which are going to be fixed in a later update, Mathijs, what is on that issue list?

Is fuel mixture simulated? When I operate the levers, nothing seems to happen with the engine instruments until the engine quits. I use SP2 and 1.01 ver Twotter. Further the right engine oil temperature seems to be quite cold compared to the left engine. Anyone else seeing this?

Should it be possible to take off with totally feathered propellers? The levers all back, just reduced engine power it seems like.

These questions may already been posted, i`ve tried to keep up with all written here. I`m sorry for this.

Best Regards

Trond

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Hi Trond.

The fuel levers are NOT mixture levers.

In the real Twin Otter as well as the Aerosoft version they are simple on/off levers.

The oil temperature gauges are on the list for the next update.

The "thrust with feathered propellers" might be a FSX "bug", but will probably also be looked into by the developers.

Finn "Wothan" Jacobsen

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Trond A

The Twin Otter uses turboprop engines, which don't have a mixture control like piston engines do. Turboprops automatically adjust their fuel/air mixture, and the condition levers on most turboprop aircraft only alter the minimum amount of fuel going into the engine, which essentially changes the idle speed of the engine. The condition levers on turboprops are most often used to slow down the engine idle speed for taxi operations (which saves brake wear), and are left in the "high" position from takeoff until landing.

As for taking off with feathered props, that's not something that is normally (if ever) done with multi-engine aircraft, but it might be possible at the expense of using a lot of runway and trashing the engines.

When a propeller is feathered, it isn't 100% parallel to the airflow, since propeller blades have a twist to them, which means that some part of the blade will always be at a bit of an angle to the air moving past it. This means that if a feathered propeller is hooked up to an engine with enough power and torque, it will produce some thrust, but will require an obscenely high power setting of the engine to do so.

I don't know the specifics of the propellers fitted to the Twotter, but can I ask why you were taking off with the props feathered in the first place?

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Thanks for clearifying these matters. Was not aware these were only manual shutdown of fuel. BTW, Hope they fix the fuel selector it seems a bit puzzling.

As for taking off with props feathered, was just testing the realism of the flying model and what the levers do and cannot do, as for now no-one is billing me for those turboprops 8) As a curiosity I saw one of the RNoAF 100 ver Twotter take off with HUGE AoA on one engine during a airshow. Impressive!

Is there another way of setting up joystick throttle so when down to a certain level, engine power reverses? I think this was possible with some early ver of FS.

Trond

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Doing a one engine takeoff with a two-engine aircraft is something that nearly never will be done. I avoid using the totally never answer because there have been a rare few dire emergency situations where it was done with some aircraft that featured both engines on the centerline of thrust -- like the Cessna Skymaster for example.

The C-130 is a four engine aircraft and therefore there are procedures in place for a pilot to conduct a three engine takeoff (one engine shut down). However, it takes a pretty high level of command approval on a case-by-case basis, or for the crew to be in danger (like their airport being under attack) and death will result if the crew doesn't takeoff immediately.

There were a few cases of such a thing during the seige of Khe Sahn in the Vietnam War. One engine failed to start and with a plane full of wounded the base came under mortar attack and the aircraft commander immediately took off anyway on three good engines.

The Twin Otter would be suicide to attempt a single engine takeoff. Like most general aviation twins, the engines are located so that asymetric thrust is too powerful for the rudder to counter until the aircraft reaches a certain airspeed. The thin red line marked on the airspeed gauge near the bottom of the white arc (stall speed) is the point at which at sea level, with full power on the good engine, below that speed the rudder cannot counter the asymetric thrust along the yaw axis.

Therefore, if an engine fails on takeoff run, the only acceptable emergency response is for the pilot to IMMEDIATELY chop power to both engines and full brake. Even running off the end of the runway beats the alternative. Because below red line, if you keep full power on the good engine the airplane will yaw and roll and enter a spin into the ground and you are dead!

This is why the single most dangerous part of twin engine flying is an engine failure immediately after reaching rotation speed (Vr) and lifting off from the runway. If this dire thing happens, then the only acceptable action is for the pilot to chop the throttle to idle and do a forced landing straight ahead, or if something straight ahead will kill him, doing small turns to avoid death while landing more or less straight ahead.

Now, you're probably thinking, "Well if that's true then how do you land on one good engine?" The reason is that if you throttle down then the torque and p-effect that produces the asymetric thrust is reduced. If you put the throttle to idle for the flare to landing, then you mostly eliminate the asymetric thrust and can safely go below red line speed (Vmca) for the touch down.

BTW: Is Aerosoft going to patch the lack of feathering props?

Cheers,

Ken

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What are you saying? That i`m lying? This was done as a part of the airshow, as a deliberate action. If you don`t believe it thats fine. The Twinotter had a long and fast roll prior to takeoff building more energy than during a normal takeoff. The Airshow was held at Andøya, Norway. A F-16 also did a real slow flyby with extreme AoA, at 90 kts. Only a very few of the Norwegian F16 jocks are allowed to do this manouver. But I guess that according to you is impossible too? And last but not least a P3C did a 120 degree bank. No roll mind you.

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Thanks for that Ken, nicely explained.

However...(and for Trond A's benefit) :wink:

I have a Twin Otter Manual (that's the extent of my real life experiences with her!) and it states that:

she'll fly good on one engine IF....

1. If an engine fails above VMC (64 knots in a Landplane) and a decision is made to continue the take-off proceed by maintaining heading by application of rudder and lowering the wing against the live engine as necessary (to a maximum of 5 degrees). Lower nose.

2. Advance power levers up to the T5, torque or NG limit, whichever is reached first.

It then posts the best climb speed on a single engine is 80 knots IAS with 10 degrees of flaps.

It's possible, but like you say not advisable.

Haven't tried it with Aerosoft's Twin Otter yet though.

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That's it....it's the end of the world!

I found a BIG oversight on the Twin Otter.

On the kneeboard reference page it says that maximum take-off weight is 15,500lbs or 5670kg.

It should be 12,500lbs (which is also 5670kg). I overloaded my plane and now she won't fly good even on TWO engines. :shock:

I'm thinking about demanding a full refund! :lol::lol: :wink:

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What are you saying? That i`m lying? This was done as a part of the airshow, as a deliberate action. If you don`t believe it thats fine. The Twinotter had a long and fast roll prior to takeoff building more energy than during a normal takeoff. The Airshow was held at Andøya, Norway. A F-16 also did a real slow flyby with extreme AoA, at 90 kts. Only a very few of the Norwegian F16 jocks are allowed to do this manouver. But I guess that according to you is impossible too? And last but not least a P3C did a 120 degree bank. No roll mind you.

I think all Ken was saying was that single engine takeoffs are almost never done on conventional twins except for dire emergencies (or airshows).

Did the Twin Otter you saw take off with one engine shut down, or just idling?

I can see where taking off with one engine shut down would be possible, if the pilot added power to the running engine slowly to allow the rudder to become effective as the aircraft accelerated, and kept the aircraft on the ground until it had accelerated past VMC. Since VMC for the Twin Otter is only 64KTS, it would be possible to use reduced power on the running engine to accelerate faster than that on the ground, after which point the power could be increased to get off the ground and climb out.

Again, just because it's possible to do something with an aircraft doesn't make it safe, sorta like using a toaster in the bathtub.

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Hi! My first post here :)

Just want to thank Aerosoft for a wounderful airplane! Cant wait to the Wideroe paint comes out! Truly amazing :)

But I`v got a little problem with the sounds. When I startup I`m not getting the feathering sound, just some rumbling noise. Have the same problem when shutdown, just some rumbling. I dont know if its my sound-card or something? Also the sound gets stuck at high RPM on default airplanes, not on the Twotter, if its any help. If you would help me out it would be lovely!

Best Regards Johan Holmseth

Just want to try again, since it came so much questons after my post :)

Anybody know?=)

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Thanks for the support Daytonite_Andy! Yes, i agree it seems not advisable, but its possible and someone approved the manouver inspite of its obvious dangers.

During an airshow many dangerous manovers take place, but I guess its a calculated risk they choose to accept. On the other hand I guess they are not acting like kamikaze either :wink:

Don`t know if the other engine was running or not, but the right propeller were only barely turning. So unless its possible to disengage the engine from its gearbox and propeller while the engine runs I guess it was off and feathered.

I also would imagine the plane was as light as possible, keeping fuel levels to the absolute minimum.

Trond

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Thanks for the support Daytonite_Andy! Yes, i agree it seems not advisable, but its possible and someone approved the manouver inspite of its obvious dangers.

During an airshow many dangerous manovers take place, but I guess its a calculated risk they choose to accept. On the other hand I guess they are not acting like kamikaze either :wink:

Don`t know if the other engine was running or not, but the right propeller were only barely turning. So unless its possible to disengage the engine from its gearbox and propeller while the engine runs I guess it was off and feathered.

I also would imagine the plane was as light as possible, keeping fuel levels to the absolute minimum.

Trond

I've seen the same Twotter take off as Trond, performed at Sola in 1987 by 719 skv. Impressive. Equally impressive is "vareheisen" (Norwegian for something like an elevator used for goods only... lol) take off.

Mind you, 719 were used to go everywhere, and I mean everywhere using wheels and skis. Their mission was primarily support/light transport to the RNoAF units stationed in Northern Norway, Ambulance ops etc. On the darker side of things, spec ops and recce (one was able to be equipped with a "good" camera) close to the Soviet border. They wanted to write a sqn history book at one time but the brass refused.....

Also, one was used for Penguin ASM testing and later it also played a role in the initial testing of the NSM ASM, now almost finished and further tested by our remaining F-5 fleet.

OT: We had demo-pilots like the KLu before. Nowadays money is not allotted to the training of dedicated display pilots. So if you see a Norwegian F-16 display these days it's usually at least a pair, and is operational flying with heavily configured aircraft in the swing-role. Chaff/flare and pyrotechnics on the ground, explosives and small piles of dry concrete powder makes a mess.... lol and is a big part of it.

Best

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