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DHC-6 Twin Otter development

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Re: DHC-6 Twin Otter development

Postby lanbo64 » Mon Jan 04, 2016 5:45 am

Beaver wrote in Mon Jan 04, 2016 12:04 am:I'm using the dialog for the Autopilot, because the buttons on the panel don't seem to work consistently for me, but that's also probably my fault.


There is only one case that the autopilot buttons do not work: your aircraft gets iced... Turn on the pitot heat, prop deicing, window heat, and also, if you are landing on a dirt, grass, snow airstrip, turn on the intake deflector.

When the environment is high humidity, and the temperature is about to 0 Celsius Degree, you have to protect the aircraft from icing hazard.

In the real DHC6 the intake deflectors need more than 80% of N2 (Ng) to extend, but in the current version, it will extend when you have power.

Hope this help.
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Re: DHC-6 Twin Otter development

Postby lanbo64 » Mon Jan 04, 2016 5:49 am

dg-505 wrote in Mon Jan 04, 2016 5:37 am:As far as I know, both the rudder and the evevator trim are on the console right next to the pilot's seat:


What is the white buttons on the left hand side of the yoke. Are they only PTT buttons? But they have two...
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Re: DHC-6 Twin Otter development

Postby dg-505 » Mon Jan 04, 2016 7:49 am

I'm not sure. Do you know if the Twin Otter has Rudder and Aileron Trim?

Another thing regarding the FDM: It seems to me that the plane reacts very slowly to the aileron input. I don't know how it behaves in reality, but I think it should be a bit more agile on the aileron.
What do you think about this?
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Re: DHC-6 Twin Otter development

Postby lanbo64 » Mon Jan 04, 2016 8:51 am

dg-505 wrote in Mon Jan 04, 2016 7:49 am:I'm not sure. Do you know if the Twin Otter has Rudder and Aileron Trim?

It seems to me that the plane reacts very slowly to the aileron input.


I don't know, but in the real DHC3, there is nothing on the left yoke. In DHC6, the buttons may be for ailerons trim.

I can add more lift and drag to the ailerons, so the aircraft will roll faster. It is not that hard.

But in flight simulator software, such feeling is difficult to be emulated. For example, in real world, the SR20's yoke and rudder are extremely hard to move, but feeling of the Piper or Cessna 172 is more relaxed and easy. These three guys have similar FDMs, but they have very different feeling.

Maybe we can ask everyone here to vote if people prefer slow or fast reaction (before I can find a real DHC6 pilot to test).
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Re: DHC-6 Twin Otter development

Postby dg-505 » Mon Jan 04, 2016 10:48 am

Afaik FG unfortunatelry doesn't (yet) provide Force Feedback, i.e. we cannot simulate the drag against yoke movement in the joystick.
At least IMHO the roll speed should be simulated only by taking into account the aerodynamical forces of the aileron surface; and independent from the drag against the yoke.
I know a real Twotter Pilot, so I can ask him how the Twin Otter reacts on the aileron.


If you want to redo the electrical system, could you include implementation of the circuit breakers? If so, I can make 3D models for them.
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Re: DHC-6 Twin Otter development

Postby Beaver » Mon Jan 04, 2016 12:15 pm

I prefer slow reaction to fast reaction, for several reasons. One is that it is easier to be precise, especially with not-so-excellent joysticks. Another is that flying planes like the Twin Otter requires a lot more forethought and planning than smaller aircraft, and a high responsiveness would ruin that feeling. After all, you're wielding five tons of aircraft (plus fuel and payload), not a nimble Skyhawk.

Another way to approach this is to look at how real Twin Otters on youtube are rolling. If the same angular speed is too hard to achieve with a computer yoke, then it's probably too slow.
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Re: DHC-6 Twin Otter development

Postby lanbo64 » Mon Jan 04, 2016 1:25 pm

Let's just wait for more results or real pilots' idea about how to improve the FDM ailerons.

For the electrics, everything can be implemented with proper codes. I am now reading Buckaroos' tutorials for the electrical system.
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Re: DHC-6 Twin Otter development

Postby dg-505 » Mon Jan 04, 2016 3:50 pm

I just wrote to my friend and asked him about the switches on the yoke, the trim axes and levers, the circuit breaker panels, and about the oil tempetature, because I noticed that the oil temp stays always at the same value during the flight.
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Re: DHC-6 Twin Otter development

Postby lanbo64 » Mon Jan 04, 2016 4:33 pm

dg-505 wrote in Mon Jan 04, 2016 3:50 pm:oil temp stays always at the same value during the flight.


Oil temp has not been implemented in this aircraft. According to the XML codes, the oil temp gauges are just nothing more than another N2 gauges.

In real world, the oil temp is based on the OAT, and the changing is slower in low OAT, then, frozen. When we add N2 power, the oil will be heat and come back to a normal temperature. This process can be done by writing a nasal code, not very difficult. I can do that.

Also, the propellers' animation currently is just based on N2 too, this is wrong, but people can't actually feel it because after the engine spin, the propellers are disks. For more realistic and accuracy purpose, I will fix them in the future too.
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Re: DHC-6 Twin Otter development

Postby MIG29pilot » Mon Jan 04, 2016 4:36 pm

dg-505 wrote in Mon Jan 04, 2016 10:48 am:I know a real Twotter Pilot...

Lucky beast!
Although, I do have a great Uncle or something like that who flew B-48s loaded with nuclear weapons over the Pacific near Hawaii in the 50s for Strategic Air Command, ready to go start WWIII when ordered.
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Re: DHC-6 Twin Otter development

Postby tauchergreg » Mon Jan 04, 2016 5:56 pm

Hello to all DHC-6 300 developer and friend's

at first I wish you all a Happy new Year!


Can you ask your frind about the minimum taxi speed without brakes on engine and propeller on idle ?


Best regards
C160 Transall , Twin Otter DHC6, both with small modification
EF2000
ETMN & EDXN under development
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Re: DHC-6 Twin Otter development

Postby lanbo64 » Mon Jan 04, 2016 6:58 pm

tauchergreg wrote in Mon Jan 04, 2016 5:56 pm:Can you ask your frind about the minimum taxi speed without brakes on engine and propeller on idle ?


I used to challenge the taxi speed on idle in my previous post on this forum. I even challenged if the aircraft can be fully braked on the ground in 50 Toque Pressure. However, latter, I finally got informed that the PT6-27A can definitely move the aircraft even on idle, but the speed is highly depended on the surface. It is different in grass, dirt, or asphalt. In 50 Toque Pressure, the aircraft would even move with full brake.

Also, the Yasim has a limit that the aircraft will work so bad if the wheels' friction data setting too high.

These two reasons above make me stop making change.

If in the future, real pilots confirm a lower taxi speed and higher brake capability, I can write a fake revere-thrust in nasal code to make it more realistic.
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Re: DHC-6 Twin Otter development

Postby MIG29pilot » Mon Jan 04, 2016 8:45 pm

Is it possible to use two fdm's on an aircraft at once?
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Re: DHC-6 Twin Otter development

Postby lanbo64 » Mon Jan 04, 2016 9:51 pm

MIG29pilot wrote in Mon Jan 04, 2016 8:45 pm:Is it possible to use two fdm's on an aircraft at once?


Then, that's called "two aircraft". :mrgreen:

In fact, we already have 3 different FDMs now. The wheels, skies, and floats have their own FDM.
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Re: DHC-6 Twin Otter development

Postby MIG29pilot » Mon Jan 04, 2016 10:37 pm

Three fdms being used at the same time I mean.
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