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[1.4.x-1.8.x] Airplane Plus - R26.4 (Fixed issues/Github is up to date) (Dec 21, 2019)


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1 hour ago, Salvator said:

Hey, could anyone explain to me, how do the turboprop engines work? The Kitty only achieves max thrust on takeoff and in vertical flight, in level flight the thrust falls to 8.5 kN. The Predator behaves even more weird: in level flight the thrust rises above 15 kN during takeoff and then falls back to the aforementiones level. When pitching up the thrust rises, but once vertical, the thrust starts falling to some 15 kN. It should be capabale of 80 kN. Why do these engines behave like that?

The thrust for all airbreathing engines depends on the mach number. There is a curve in the config that defines the relationship. In general APP engines have very high thurst at low speed, taper off as speed increases, then drop off sharply when the engine reaches its intended top speed.

The thrust falloff is to simulate thrust lapse, that is as you increase your speed through the air, the jet exhaust/propwash has less of a speed difference compared to the surrounding air. This causes reduced thrust and efficiency IRL. Some has a little lower static thrust to simulate stalled out props, or spool up time for turbines I think.

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28 minutes ago, neistridlar said:

The thrust for all airbreathing engines depends on the mach number. There is a curve in the config that defines the relationship. In general APP engines have very high thurst at low speed, taper off as speed increases, then drop off sharply when the engine reaches its intended top speed.

The thrust falloff is to simulate thrust lapse, that is as you increase your speed through the air, the jet exhaust/propwash has less of a speed difference compared to the surrounding air. This causes reduced thrust and efficiency IRL. Some has a little lower static thrust to simulate stalled out props, or spool up time for turbines I think.

This doesn't seem to be the case, I see no correlation between speed and thrust. Or better to say there is a correlation, but a different one than you're speaking about. For example the Kitty: the thrust grows during takeoff up to the max kN, but as soon asi the speed reaches cca 170 m/s the thrust drops so that i can't fly faster than that. But if i start to pitch up from the level flight the thrust grows as if the engine tried to maintain the same speed in vertical flight. Such behaviour doesn't really make sense and it doesn't seem to match the behaviout you're describing, does it?

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6 minutes ago, Salvator said:

This doesn't seem to be the case, I see no correlation between speed and thrust. Or better to say there is a correlation, but a different one than you're speaking about. For example the Kitty: the thrust grows during takeoff up to the max kN, but as soon asi the speed reaches cca 170 m/s the thrust drops so that i can't fly faster than that. But if i start to pitch up from the level flight the thrust grows as if the engine tried to maintain the same speed in vertical flight. Such behaviour doesn't really make sense and it doesn't seem to match the behaviout you're describing, does it?

KSP doesn't simulate each blade as a wing that propels the aircraft forward, unless you're using robotic parts with no sounds. "Simulate" is key, in reality, like neistridlar said, it's just Mach Speed * Thrust Multiplier, aside from Atmospheric Pressure * Thrust Multiplier.

KSP Jet Engines have spool time so they can delay this effect but they behave the same way. The props of course have basically no spool time needed for reasons already obvious, this just means that when your speed slows down, the engine immediately adjusts the thrust multiplier that "keep your speed".

When the mechanic is supposed to be normal power thrust at lower speeds such as take off, and weaker as the speed is less efficient for the blades, this also means slowing down while going up gives you higher power in that same curve. If the engines are powerful enough, it will keep the speed. This can't be done on earlier era engines. If you use KAX you'll know its engines are simulating it better because it's not powerful enough to "keep your speed" when at high angles of attack.

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On 10/11/2019 at 10:26 PM, blackheart612 said:

I'm not necessarily inactive, I check the forums everytime I can. I'm just trying to earn money on the side by drawing 2D art commissions. Like I've already said before. I've already one fixing the slat issue but trying to find the time to fix the wrongly referenced decal textures.

Any estimate when you'll have that slat fix out for download?

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  • 2 weeks later...
On 10/13/2019 at 8:16 PM, Salvator said:

This doesn't seem to be the case, I see no correlation between speed and thrust. Or better to say there is a correlation, but a different one than you're speaking about. For example the Kitty: the thrust grows during takeoff up to the max kN, but as soon asi the speed reaches cca 170 m/s the thrust drops so that i can't fly faster than that. But if i start to pitch up from the level flight the thrust grows as if the engine tried to maintain the same speed in vertical flight. Such behaviour doesn't really make sense and it doesn't seem to match the behaviout you're describing, does it?

This is how propellers work. "Real" propellers based on LiftingSurface (BG props and stock ones) work in a similar way: when you accelerate, blades begin to create more drag and less lift and the thrust decreases. When you pitch up you decelerate and blades produce less drag until you reach the same velocity.

Edited by Manul
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I have a question about propeller strength.  I have no real IRL knowledge of aviation (beyond the passenger level) so assume I'm the complete noob that I truly am.

How does one judge the strength of propellers from the AP mod?  I was looking at the 'Kitty' (the first level prop) and comparing it to the one's you unlock second in career mode.  I did notice a standing force rating for props.  The Kitty seemed to be 65 kN while the second tier props were all in the 20s kN range.  Am I reading these wrong?  

Essentially I'm looking to make a plane that I can use to fly around Kerbal to collect some science data for contracts.  I'd prefer to  travel a bit faster than I seem to be able to do with my starter plane...  So I'm wondering what props would give me more speed.  I assume plane mass will also be a factor, so any suggestions there would be great.

 

Thanks!

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3 minutes ago, dochockin said:

I have a question about propeller strength.  I have no real IRL knowledge of aviation (beyond the passenger level) so assume I'm the complete noob that I truly am.

How does one judge the strength of propellers from the AP mod?  I was looking at the 'Kitty' (the first level prop) and comparing it to the one's you unlock second in career mode.  I did notice a standing force rating for props.  The Kitty seemed to be 65 kN while the second tier props were all in the 20s kN range.  Am I reading these wrong?  

Essentially I'm looking to make a plane that I can use to fly around Kerbal to collect some science data for contracts.  I'd prefer to  travel a bit faster than I seem to be able to do with my starter plane...  So I'm wondering what props would give me more speed.  I assume plane mass will also be a factor, so any suggestions there would be great.

 

Thanks!

 

I use the kitty turboprops quite a lot. AFAIK they are only really any good at low altitudes and speeds. The larger engines, while producing less thrust, I think are more capable at higher altitudes and speeds.

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7 hours ago, NEVR44 said:

Firespitter does not work in 1.8 in conjunction with MechJeb2

Because there's not been a KSP 1.8 version of Firespitter released.  The KSP 1.7.3 to 1.8 transition is such that most mods *need* to be recompiled and often rebuilt.

@RoverDude said he'd get to it this week.

 

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2 hours ago, Oscar_Muffin said:

 

I use the kitty turboprops quite a lot. AFAIK they are only really any good at low altitudes and speeds. The larger engines, while producing less thrust, I think are more capable at higher altitudes and speeds.

Thanks!

I noticed that there was some discussion about this above in the thread which did help a bit too.  What numbers or values in the "Right-Click part view" in SPH/VAB would help me figure out relative prop strength or speed?

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15 minutes ago, dochockin said:

Thanks!

I noticed that there was some discussion about this above in the thread which did help a bit too.  What numbers or values in the "Right-Click part view" in SPH/VAB would help me figure out relative prop strength or speed?

Not a whole lot really. You just need to go into sandbox and try them out. Same way there really isn't any way to see that the panther engine doesn't work too well above 600m/s but the whiplash does.

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7 hours ago, Numberyellow said:

Here's my question: Why in the hell isn't firespitter already an integrated KSP feature?

Because KSP stock didn't cared about propellers until Serenity. And now, with Serenity, makes no sense on internalizing a feature already covered by a paid DLC.

Firespitter is a niche. A pretty big niche, as it appears, but yet, a niche.

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7 hours ago, Lisias said:

Because KSP stock didn't cared about propellers until Serenity. And now, with Serenity, makes no sense on internalizing a feature already covered by a paid DLC.

Firespitter is a niche. A pretty big niche, as it appears, but yet, a niche.

Bah. It's added functionality.... and it's damned good. I'm not sure i follow, when you say it's a niche.

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@blackheart612

Heads up. The stock nosecones have had a bit of a reshuffle so some of your cones configs are pointing to the wrong place. New path should be...

texture = placeholder , Squad/Parts/Aero/cones/Assets/Cones

You're just missing the Assets folder.

 

Edit: Oh wow, DXT3 textures too...I hope you have the original artwork so you can just re-export.

Edited by Manwith Noname
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43 minutes ago, djv25 said:

Firespitter not compatible with 1.8, game does not load expansions with this mod installed, is a shame, I really like this mod

It's doing it now. KAX uses Firespitter, and the latest is working for me.

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Just what I wanted and even more! I love the design and quality. Have you ever considered adding fictional based parts to the pack? If so, I have a nice helicopter that needs a home in KSP modding comunity

 
 
 
 
Spoiler

Image result for sa 2 samsonRelated imageImage result for sa 2 samsonImage result for sa 2 samsonImage result for sa 2 samson

 

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On 10/13/2019 at 10:34 AM, Salvator said:

Hey, could anyone explain to me, how do the turboprop engines work? The Kitty only achieves max thrust on takeoff and in vertical flight, in level flight the thrust falls to 8.5 kN. The Predator behaves even more weird: in level flight the thrust rises above 15 kN during takeoff and then falls back to the aforementiones level. When pitching up the thrust rises, but once vertical, the thrust starts falling to some 15 kN. It should be capabale of 80 kN. Why do these engines behave like that?

They produce significantly less thrust over a certain speed. 
It's a standard behavior of propeller engines, but the turboprops are the only ones with enough thrust to reach that speed under their own power quickly in most designs.   This behavior is what makes propeller based planes fly so differently.

On 10/29/2019 at 2:54 PM, Manwith Noname said:

@blackheart612

Heads up. The stock nosecones have had a bit of a reshuffle so some of your cones configs are pointing to the wrong place. New path should be...

texture = placeholder , Squad/Parts/Aero/cones/Assets/Cones

You're just missing the Assets folder.

 

Edit: Oh wow, DXT3 textures too...I hope you have the original artwork so you can just re-export.

You can convert DXT3 to DXT5 losslessly with some quick conversion programs.  They use the same algorithm.  DXT5 just has a full separate Alpha channel.

Edited by Ruedii
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