The Optimist

(Stock Electric Propeller Vehicle Showcase): Bringing power to the people!

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Made a new transport airplane. It can carry one full orange tank, possibly even 40t of cargo. One issue I've noticed is no matter where I've placed the orange tank inside the cargo bay it was never shielded from the drag.

Also I've made small improvement to the engine by adding the long I-beam as the root part on the rotor, with other parts on the rotor auto struted to the I-beam, it eliminated almost all wobbling from the engine.

Max speed is about 153 m/s for the empty airplane and about 125 m/s when carrying 22t of cargo.

orcre4U.png

QUu1KCR.png

DFFGc9R.png

Link to the craft file https://kerbalx.com/Rade/Condor

Edited by _Rade

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The fairing bearings do not work for me, unfortunately. I'm going to have to stea- I mean borrow someone else's design.

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On 12/4/2016 at 5:32 AM, _Rade said:

I've made a breakthrough when it comes to the stock electric propellers.

this one set a speed record of 200 m/s, craft file https://kerbalx.com/Rade/T-4A-Soko

Thank you @_Rade for the nicely designed propeller engine.  I had been looking for a powerful, compact electric engine to make an Eve ocean exploration vehicle.  I stripped off all of the plane parts, and ended up with an amphibious craft that can do a sustained 20m/s across Eve's ocean.

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Spoiler

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Xb32m7b.png

F3yhScN.png

4ZgpXOm.png

 

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I´ve put more time into this than I´d like to admit, but finally I got this to work at Duna.

VdYnKoM.png

And it doesn´t just work, but actually flies pretty well with top speeds of around 130m/s. The propellers spin faster in the thinner atmosphere, so the uneven forces on the propeller blades are a bigger problem than on Kerbin. So as a nice sideeffect my Kerbin based propeller planes got a lot smoother and better along the way. :)

Now I´m rushing through my career game to the next Duna launch window to fulfill 2 atmospheric flight contracts. The only problem: When I reload this plane with detached motors, they jump out of their fairings before they can redock. Which looks funny but isn´t particulary desirable. Haven´t found a sollution to that problem so far. But at least I´ll get one glorious flight. :wink:

Edit: Craft file: https://kerbalx.com/herrmue/Duna-Prop-Plane

Edited by KerrMü
added craft link

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On 16.12.2016. at 10:43 PM, The Optimist said:

The fairing bearings do not work for me, unfortunately. I'm going to have to stea- I mean borrow someone else's design.

Sorry for the late reply I've been little bit busy lately.

I'm not sure what sort of problem you've got with getting these bearings to work.

The main issue I've had with the fairings is that they can be somewhat buggy, as I've mentioned in previous post every time you add some parts inside the fairing or you use the Ctrl+Z to undo something you should rebuild the faring, or else it is probably not gonna work.

 

On 21.12.2016. at 6:27 PM, PointySideUp said:

Thank you @_Rade for the nicely designed propeller engine.

Glad that I could help, that's a nice little boat.

I was planning to send some sort of hydro-plane to Eve in my carrier, but lately I didn't have that much time for KSP. Also I need to come up with some way to re-dock the propellers to the plane, otherwise as soon as you leave the physics range the whole thing will fall apart.

 

On 23.12.2016. at 6:03 PM, KerrMü said:

I´ve put more time into this than I´d like to admit, but finally I got this to work at Duna.

Nice to see you got this working. I tried to use a few different propellers on Duna but because of the thin atmosphere they would always spin to fast and then fall apart.

btw. how many SAS wheels did you use for these engines.

 

On 23.12.2016. at 6:03 PM, KerrMü said:

The only problem: When I reload this plane with detached motors, they jump out of their fairings before they can redock.

For this to work you'll need some way to re-dock the propellers to the plane when it is not in use.Few pages back vitekc45c posted this
 

Spoiler

 


 

I didn't have time to test if this works with fairings.

 

 

 

Edited by _Rade

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6 hours ago, _Rade said:

btw. how many SAS wheels did you use for these engines.

Hi Rade

I use 8 small SAS wheels per engine. I found that you need around half the power on Duna than you would put on a plane for Kerbin.

The trick was: 1. Your i-beam trick

                       2. I stabilized the Stayputniks with a ring of 8 thermometers

(and I´d like to think, that the fairing closed around the propeller base also helps a bit.)

The engines have docking ports, but I can´t redock them. Is there a trick I don´t know about? Tips are very welcome everybody.

I added the craft file link to the post above if you want to take a look. Btw, I tried your Condor yesterday. That´s a very good plane. Well done.

So long and merry christmas :)

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The thing about docking ports is that once you undock, you have to move away to a certain distance before you are able to redock that same docking port.

That's why the solution from vitekc45c works. He used the docking port on the side of the rotor instead of it being inline as usual. So once the rotor starts spinning the docking port can actually move out far enough, but once it stops spinning it can easily redock to the plane.

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Currently working on (fairing based) Mk 2 engine, but Im having trouble with kraken eating the propeler blades and RTGs. On the latest test flight I had to ditch an engine after one of its blades "colided with the fairing".

PuqasM4g.png

Edited by vitekc45c

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18 hours ago, vitekc45c said:

On the latest test flight I had to ditch an engine after one of its blades "colided with the fairing".

PuqasM4g.png

 Congrats on the successful recovery after a mid-air event.

 I imagine it like this. - You're 1000 meters up, straight out from the KSC.  BANG!  What was that?  Spin camera around and see debris trailing.  Plane yaws right but steady hands hold her tight.  Prop adjustments quickly made as you toggle between engine nodes.  You ease her onto a more direct path for the island runway for an unscheduled emergency landing.  A bead of sweat develops as you realize there's a full crew by default. :-)

 

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I've managed to get several fairing engines running, and so far they are offering unparalleled performance. My one problem with them is their tendency to overspeed and explode, which the fuselage engines nearly never do.

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1 hour ago, klond said:

 Congrats on the successful recovery after a mid-air event.

 I imagine it like this. - You're 1000 meters up, straight out from the KSC.  BANG!  What was that?  Spin camera around and see debris trailing.  Plane yaws right but steady hands hold her tight.  Prop adjustments quickly made as you toggle between engine nodes.  You ease her onto a more direct path for the island runway for an unscheduled emergency landing.  A bead of sweat develops as you realize there's a full crew by default. :-)

 

It was a lot less eventfull than that:

I was about 2.5k up, descending down to the island runway when two puffs of smoke came out of engine 1, I checked the flight log to find that one blade and RTG were gone. So after pulling up and staging the fairing, i watched wobly SAS-noodle spiraling its way into the ocean.:)

Edited by vitekc45c

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That's actually pretty neat, that you could get rid of the broken engine like that.

I never had a problem with the blade colliding with the fairing. Alto that is probably because I'm using the nose cone adapter at the front so the blades can't get anywhere near the fairing.

btw. those struts on the blades, do they help with the blades moving away from the rotor at high rotation speeds. Usually I just autostrut them to the root or grandparent part, and that seems to work fine.

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Struts + autostruts is what I use, ridgid attachment works better but can cause blades to snap off when stressed (steep climb/ descent etc.).

It doesnt help that much, Id say olny about 10-15% better than autostruts alone.

Edited by vitekc45c
Much grammar, such typos, wow.

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Ok, that makes sense since they are attached perpendicular to the part that's close to the blade, instead of the autostrut that's most likely attached at an angle. Alto I'm not sure if using the struts is worth it because of the added drag.

 

6 hours ago, The Optimist said:

I've managed to get several fairing engines running, and so far they are offering unparalleled performance. My one problem with them is their tendency to overspeed and explode, which the fuselage engines nearly never do.

The overspeed problem. For me it only happens if I try to fly the plane above the certain altitude. For the first version of the fairing engine I've made, this would happen somewhere around 6.5k. The new engine I've made for Condor worked just fine at 6.5k, I think I didn't go above the 8k because the plane wouldn't climb any higher.

I'm gonna have to make a smaller plane with this engine, to see just how high it can go before the overspeed happens.

Edited by _Rade

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8 hours ago, The Optimist said:

 

1 hour ago, _Rade said:

The overspeed problem. For me it only happens if I try to fly the plane above the certain altitude. For the first version of the fairing engine I've made, this would happen somewhere around 6.5k. The new engine I've made for Condor worked just fine at 6.5k, I think I didn't go above the 8k because the plane wouldn't climb any higher.

I'm gonna have to make a smaller plane with this engine, to see just how high it can go before the overspeed happens.

To add, it can be fixed by giving the wings more pitch. This makes sure that the AoA of the props don't go negative.

I managed to get 10k altitude and 140m/s max speed with a 40t commercial aircraft, can't post the picture right now. Lift decreases too fast over there, so I couldn't fly over there.

I have a question: What's the most flexible part in ksp? I want to control the pitch of props. But it only allows 2 modes of angles...

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I would love to see the the picture.

As for the flexible parts, in older versions of KSP before the wheels where upgraded, people where building the rover suspensions stacking the spider engines or radial decouplers. Essentially any part of will be flexible if you stack it enough.

I'm guessing you want to use this to make something similar to the wing on the F-8 Crusader . You might be able to use the landing legs to control the the angle of the wing, because they can push on the parts that belong to the same aircraft.

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4 hours ago, _Rade said:

I would love to see the the picture.

As for the flexible parts, in older versions of KSP before the wheels where upgraded, people where building the rover suspensions stacking the spider engines or radial decouplers. Essentially any part of will be flexible if you stack it enough.

I'm guessing you want to use this to make something similar to the wing on the F-8 Crusader . You might be able to use the landing legs to control the the angle of the wing, because they can push on the parts that belong to the same aircraft.

Thanks for the answer and tips!

Well, I thought I was wrong about the speed, since the first try gives around 70m/s on the altitude.

And then, after the refined attempt... I got 166m/s.

(Please ignore the poor aesthetics of the plane; :P)

Spoiler

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There was one problem: The props broke over 170m/s.

Edited by Reusables
Oops; Pictures arranged in wrong order.

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Interesting engine configuration, I'm not sure why you're using 3 fairings for each engine. One way you could do it is to have fairing go straight over the front stayputnik, then expand it to cower the SAS modules and then bring it back to 1.25 m in order to hold the rear stayputnik. That way you would have more compact engine inside a single fairing, this would considerably reduce the drag. Also you may want to use nosecone instead of the shielded docking port, that part adds a lot of drag for some reason.

 

Today I finally had some time for KSP, so I wanted to see if I can make the plane that goes faster than 200 m/s.

r7R2lb8.png
 

Spoiler

 

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I went with the minimalist approach, just two powerful engines, small wings and minimum number of parts in order to reduce the mass and drag. It's not pretty and it is a bit difficult to fly it, but it is really fast. I really wish there was a way to prevent the rotor blades from being pulled apart at high rotor rotation speeds.

At low level flight I was able to reach 240 m/s, the plane can climb to 9.5k before the wings lose lift. Also it works quite well on Eve where the max speed is about 130 m/s at low level and about 160m/s at 11k.

https://kerbalx.com/Rade/Jastreb

 

Edited by _Rade
forgot to add the link to the craft file

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2 hours ago, _Rade said:

 snip

That's great plane! I didn't expect 200m/s+ to be possible, and you did it!

 

About my prop engine, the amount of thrust was the problem in my case.

To increase thrust, I need bigger props with less angle of attack. This made the engines too unstable, as it tends to be bent and penetrate throught the fairing. So I had to go with this design.

Also the props already have too much drag, so I thought that drag by other parts are considerably small.

In addition, this grants me room to dock the props. I couldn't come up with any other way to do that. :(

 

And there's shielded docking ports... Well... That's because I want to dock it somewhere :P

I found out that they are not too draggy in subsonic speed with comparison experiment, but it could have some flaws.

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On 12/29/2016 at 6:45 PM, _Rade said:

I wanted to see if I can make the plane that goes faster than 200 m/s.

r7R2lb8.png

 I'll download this when I get home tonight.  What is the top-speed record for this category?  'Not sure I've seen anything faster that's electric.

Edit: tried it, loved it.

Edited by klond

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For me the record was 200 m/s, alto few pages back there was this crazy contraption that could reach 220 m/s.

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@Abastro and anyone intending to build an efficient propeller plane:

First off, you can have smooth blade pitch control by setting your propeller blades to Deployed and using the authority slider in flight.

Second off, though, my experiments tell me that 45 degrees is the ideal blade angle. Regardless of craft, altitude, or velocity, changing the blade pitch to anything other than 45 degrees just slows the plane down. Anyone else getting the same result? I'm having a hard time believing this, but it might just fit KSP aerodynamics.

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3 hours ago, SchweinAero said:

@Abastro and anyone intending to build an efficient propeller plane:

First off, you can have smooth blade pitch control by setting your propeller blades to Deployed and using the authority slider in flight.

Second off, though, my experiments tell me that 45 degrees is the ideal blade angle. Regardless of craft, altitude, or velocity, changing the blade pitch to anything other than 45 degrees just slows the plane down. Anyone else getting the same result? I'm having a hard time believing this, but it might just fit KSP aerodynamics.

Thanks, but I did several experiments for blade pitches with my craft, too.

My main problem was that I can't control authrity on the both side in the same time, which resulted in unstable asymmetric flight.

 

Also, I found that the ideal blade angle highly depends on drag, flight altitude and posture of the plane.

For me the 45 degrees doesn't work well, and during takeoff(or VTOL mode) shallow angle works much better. On the other hand, steep angle works better on faster speed. For example my plane has 45 degrees as blade angle for takeoff, and gets steeper for faster speed. I think this holds for other planes like Rade_'s, too.

(By steeper I mean closer to the backward)

Edited by Reusables
Additional Explanation

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On 12/31/2016 at 5:13 PM, SchweinAero said:

@Abastro and anyone intending to build an efficient propeller plane:

First off, you can have smooth blade pitch control by setting your propeller blades to Deployed and using the authority slider in flight.

Second off, though, my experiments tell me that 45 degrees is the ideal blade angle. Regardless of craft, altitude, or velocity, changing the blade pitch to anything other than 45 degrees just slows the plane down. Anyone else getting the same result? I'm having a hard time believing this, but it might just fit KSP aerodynamics.

I did my own tests of this a while back and I believe Azimech did too. In my builds I have found that in the current aero model its best to have low angle of attacks in order to decrease the drag generated by the surfaces in order for them to spin faster and generate more lift. Drag and total power of the rotors does not scale evenly with angle of attack based on how the difference in the angle of attack changes drag and the speed that they can rotate. I'm not explaining this very well but you probably get the point. 

In short usually rotors with less drag will produce more power than slow rotors with high angles of attack. This is opposite from the old aero model we had. 

Edited by Jon144

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