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Twin Otter Viking upgrade DHC6-300+

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Twin Otter Viking upgrade DHC6-300+

Postby SurferTim » Tue Nov 26, 2019 4:42 pm

I've been testing this for a couple weeks, and it seems to fly well.
Corrected a few things, but not much, until it came to the engines.
Stock version engines PT6A-27@620shp 50psi torque
Pirate version engines PT6A-34@750shp 60 psi torque (Viking DHC6-400 engines)

About 135MB download
http://www.prolectron.com/flightgear/dhc6p.zip
Landing lights require ALS and the rendering option stuff.
I use the PirateAir livery.
It should coexist with other DHC6 models. This uses a dhc6p folder name rather than dhc6.
It shows in the aircraft list as a DHC6-300+

Edit: Now on Github
https://github.com/SurferTim/dhc6p
Last edited by SurferTim on Wed Apr 08, 2020 9:16 am, edited 2 times in total.
Fly low, fly slow, land on a dime. Twin Otter DHC6-300+. https://github.com/SurferTim/dhc6p
PirateAir videos at https://www.youtube.com/user/SurferTim850
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Re: Twin Otter Viking upgrade DHC6-300+

Postby wlbragg » Tue Nov 26, 2019 5:17 pm

Nice, thank you!

Does the regular DHC6 have engine sounds that adjust to throttle control. I'm getting no variation in prop sound and it is making it difficult to judge thrust based on sound?
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Re: Twin Otter Viking upgrade DHC6-300+

Postby SurferTim » Tue Nov 26, 2019 5:30 pm

That "engine noise" you hear isn't engine noise. Turbine engines themselves are pretty quiet.
It's the props you hear.
More rpm, higher frequency.
More power, higher volume.
Take a YouTube ride on a Twin Otter from St Maarten to St Barth. It's the props.

Edit: And I did not want to make the volume so loud it was annoying at high power input, like takeoff.
Fly low, fly slow, land on a dime. Twin Otter DHC6-300+. https://github.com/SurferTim/dhc6p
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Re: Twin Otter Viking upgrade DHC6-300+

Postby wlbragg » Tue Nov 26, 2019 6:03 pm

OK, after watching St Maarten to Saba at the very end right before touching down at Saba, he is feathering the throttle for speed adjust and you can here the pitch change, very distinctly. Even more so in the Twin Otter from St Maarten to St Barth video in level flight as he cuts power.

After reviewing the difference between the 300 and 300+, the 300+ has lost the pitch or volume change on level flight when you adjust the throttle. It is working in the 300, subtle, but you can hear it. In the 300+ it is missing. It really throws you off when your expecting certain audio and visual cues simultaneously. Did maybe you have to change any properties that might account for that?
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Re: Twin Otter Viking upgrade DHC6-300+

Postby SurferTim » Tue Nov 26, 2019 6:28 pm

I'm sure I changed it. It originally sounded like a C172. More throttle, more rpm, higher frequency. Last I checked, that isn't how constant speed props work.
If you set the prop speed at 80%, the prop spins at 80% if you are applying enough power to do that, and it shouldn't take much.
It shouldn't spin any faster than 80%, no matter how much power (throttle) you apply. It will increase the blade pitch to maintain a constant speed.

When they land at St Barth, they are pulling the power way off and, yes, that causes the prop rpm to drop.
Maybe IRL, the DHC6 engine power drops off faster than the sim. I didn't see a way to adjust that.
Fly low, fly slow, land on a dime. Twin Otter DHC6-300+. https://github.com/SurferTim/dhc6p
PirateAir videos at https://www.youtube.com/user/SurferTim850
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Re: Twin Otter Viking upgrade DHC6-300+

Postby SurferTim » Tue Nov 26, 2019 7:11 pm

I found a challenge. If the main .xml and main-set.xml do not match the folder name, bad things can happen.
My folder name is dhc6p
My main xml files were dhc6.xml and dhc6-set.xml
My main xml files are now dhc6p.xml and dhc6p-set.xml
Give it a few minutes to finish uploading.
Fly low, fly slow, land on a dime. Twin Otter DHC6-300+. https://github.com/SurferTim/dhc6p
PirateAir videos at https://www.youtube.com/user/SurferTim850
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Re: Twin Otter Viking upgrade DHC6-300+

Postby SurferTim » Wed Nov 27, 2019 12:36 am

I have it straightened out. Works good now.
If you want to fly the floatplane version, remember to retract the landing gear (ground handling wheels really) before taking off from water. They are down by default.
I haven't tried the ski version yet.
Fly low, fly slow, land on a dime. Twin Otter DHC6-300+. https://github.com/SurferTim/dhc6p
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Re: Twin Otter Viking upgrade DHC6-300+

Postby wkitty42 » Wed Nov 27, 2019 2:31 am

that must be the amphibious model you're speaking of with wheels and pontoons... the pontoon variation shouldn't have any wheels at all... this is one reason why there're two types with pontoons on the c172p...
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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Re: Twin Otter Viking upgrade DHC6-300+

Postby SurferTim » Wed Nov 27, 2019 9:12 am

I don't know how useful the ground handling wheels are. I have not tried to taxi out of the water and up a ramp (yet).

Edit: I don't consider it an amphibian. It is a seaplane that can get into and out of the water via a ramp.

Please download the latest version from the link above. It is a 200MB download now.
Earlier I saved some bandwidth by deleting many liveries. I felt guilty about it due to the amount of work the people put into creating them.
So, if you want the new version, you get all the liveries, including PirateAir.
Fly low, fly slow, land on a dime. Twin Otter DHC6-300+. https://github.com/SurferTim/dhc6p
PirateAir videos at https://www.youtube.com/user/SurferTim850
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Re: Twin Otter Viking upgrade DHC6-300+

Postby wlbragg » Wed Nov 27, 2019 6:19 pm

Still no pitch change. I can hear the subtle volume change but it really needs the pitch change.

Original

New version

I was looking at the sound files and couldn't easily identify what changed? Do you know what properties are not working as they used to? I even copied over the original sound file, changed the path of course, still no pitch change. Does you new engine use different properties or eliminate some?
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Re: Twin Otter Viking upgrade DHC6-300+

Postby wkitty42 » Wed Nov 27, 2019 7:42 pm

SurferTim wrote in Wed Nov 27, 2019 9:12 am:I don't know how useful the ground handling wheels are. I have not tried to taxi out of the water and up a ramp (yet).

this might be tricky because of the way that FG does the scenery... use the UFO and look underneath and you see that the scenery is basically a piece of paper so there's no ramps into the water and similar for craft to roll on to enter/leave the water... but there is an experimental airport that has something to try to do this... i just cannot remember where it is... it was discussed in the c172p dev repo when the pontoons were added... i was landing on lakes and rushing the shore pretty hard to get up on it and then taxi around on land ;)

SurferTim wrote in Wed Nov 27, 2019 9:12 am:Edit: I don't consider it an amphibian. It is a seaplane that can get into and out of the water via a ramp.

yes, there is definitely a difference between a seaplane and an amphibious like the C172p can be...
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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Re: Twin Otter Viking upgrade DHC6-300+

Postby wkitty42 » Wed Nov 27, 2019 7:51 pm

i expect it is not the sound file that changes but the properties applied to it... i don't hear the turbine/blade (??) whine in the second video, either...
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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Re: Twin Otter Viking upgrade DHC6-300+

Postby SurferTim » Wed Nov 27, 2019 7:57 pm

I posted my version. If you don't like it, don't use it.

The way I can tell how much power I am applying, I take a look at the top two gauges in the engine instrument console.

Edit: My Bad for being short. If you want to play with it, open dhc6p/Nasal/systems.nas. Search for SurferTim.
You are looking for eng_update or something like that.
Fly low, fly slow, land on a dime. Twin Otter DHC6-300+. https://github.com/SurferTim/dhc6p
PirateAir videos at https://www.youtube.com/user/SurferTim850
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Re: Twin Otter Viking upgrade DHC6-300+

Postby wlbragg » Wed Nov 27, 2019 8:36 pm

I posted my version. If you don't like it, don't use it.

Wow, that's certainly an option. :shock:

If I have offended you in any manner by noticing the sound change, I am truly sorry, it was not my intention. I appreciate the attempt at a variant engine and want to use it.

I am only trying to identify what was changed in the sound system. I assumed it was not intentional as it reduced the authenticity of the simulation and am only trying to help get it right, what is authentic in my opinion. If this is intentional and what you wanted, then so be it, I will figure it out on my own and not offer any more input to this thread.

I would still be interested in what was changed in the engine properties that would account for the sound change so I can fix it on my local version without having to go through a long debug session?
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Re: Twin Otter Viking upgrade DHC6-300+

Postby SurferTim » Wed Nov 27, 2019 8:53 pm

I apologize for being short with you.

If you want to play with the sound, it is in
/dhc6p/Nasal/systems.nas
Line 567
update_eng_sound
Fly low, fly slow, land on a dime. Twin Otter DHC6-300+. https://github.com/SurferTim/dhc6p
PirateAir videos at https://www.youtube.com/user/SurferTim850
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