slowest plane

[volcanic_wolf]

create a plane that can fly, completely fly, the slowest possible plane show the highest speed in a crash log picture. rules are no tweakscale, size doesnt matter, thats not what she said, no vtol and no mods/plugins, no downwards thrusters or forward thrusters

Edited April 3, 2016 by volcanic_wolf
not enough rules

[Foxster]

With VTOL the speed could be as little as zero. 

Also - read the challenge guide. 

[Vanamonde]

Yes, this challenge needs more structure. Please review the guide and revise your rules. 

[max_creative]

Yeah, maybe more descriptive and ban vtols and stols.

i have a 80 m/s plane. At full throttle. Sorry no pics, I'm trying to figure it out.

[Rocket In My Pocket]

I don't usually don't do challenges but I thought this one sounded interesting.

So here's my quick attempt at a slow plane.

Spoiler

Take off happens at about 15m/s. Level flight travelling in a straight line is possible at about 20m/s. If you want to have extra energy to turn and such it's about 30m/s.

Edited April 3, 2016 by Rocket In My Pocket

[volcanic_wolf]

nice

 

[Rocket In My Pocket]

1 minute ago, volcanic_wolf said:

nice

Thanks! I think I may have bent the rules a bit as it tends to fly with it's nose pointed up by about 10 degrees, which makes the engine point 10 degrees down so...sort of a downward facing thruster.

[volcanic_wolf]

no what I meant is no downward while level so you're fine

 

[zolotiyeruki]

Here's my entry.  Level flight with zero vertical thrust at somewhere around 14.5-14.7m/s.

May I suggest an amendment to the rules, to clarify the intent?

--screenshot must show something close to zero pitch
--engines must be pointed horizontally.

[DualDesertEagle]

On 6.4.2016 at 2:51 AM, zolotiyeruki said:

--screenshot must show something close to zero pitch

--engines must be pointed horizontally.

I suggest u just go with the given rules. I'll do so aswell.

 

 

EDIT: My entry has been recorded and is being uploaded!

Edited May 22, 2016 by DualDesertEagle

[DualDesertEagle]

My entry's up:

 

[AeroGav]

Jeb? What you doing up there?

Stalling speed when empty is 15 m/s.   

Put some fuel in it however, it can go faster

Slowest plane on Duna ?

These have already been beaten , i'm sure.  They also require a mod, or someone else to work the fuel transfers for you , in order to go to space - the nuke engines are attached to tanks that only hold 40 fuel, so need constant transferring in from the wings.  Eg GPOSpeedFuelPump or TacFuelBalancer

https://kerbalx.com/AeroGav/K211-Tundra-Goose

https://kerbalx.com/AeroGav/PENTA-STAR

[DualDesertEagle]

Do attempts in other atmospheres even count? There's nothing sayin' the opposite after all.

 

And I think that's definitely worth an experiment.

[Deddly]

@DualDesertEagle Which version of KSP are you running? I see you have the old wheels and I notice your plane isn't jumping up and down with joy. Are you on 1.0.5?

[DualDesertEagle]

Yup. Can't update for some reason. Doesn't accept my e-mail anymore.

[Cunjo Carl]

@Anyone: It occurs to me that the design challenge of making slow planes has a lot in common with taking flight using ions for the Ion Plane Research Challenge . It might be interesting to try retrofitting your planes with ions, and see if they fly! If you need a lot of them, Ions work nicely on the little cubic struts.

 

[DualDesertEagle]

6 hours ago, Cunjo Carl said:

@Anyone: It occurs to me that the design challenge of making slow planes has a lot in common with taking flight using ions for the Ion Plane Research Challenge . It might be interesting to try retrofitting your planes with ions, and see if they fly! If you need a lot of them, Ions work nicely on the little cubic struts.

 

Since my plane is the slowest to have taken off until now I'll tackle that and try if I can still get it to take off.

 

EDIT: Accelerating along the runway, 2.8 m/s already, with a single ion engine

EDIT 2: Won't get any faster than that with a single engine tho.

Final edit: I've tried it with 6 ion engines which required 3 gigantor panels in order to keep the batteries charged. Still not fast enough to take off. The fastest speed I could achieve was 6.3 meters per second and with all the weight of those ion engines and solar panels that's nowhere near enough.

Edited May 25, 2016 by DualDesertEagle

[Cunjo Carl]

13 hours ago, DualDesertEagle said:

Final edit: I've tried it with 6 ion engines which required 3 gigantor panels in order to keep the batteries charged. Still not fast enough to take off. The fastest speed I could achieve was 6.3 meters per second and with all the weight of those ion engines and solar panels that's nowhere near enough.

Sorry it hasn't worked out so far! Those little ion engines really do a pittance for thrust in Kerbin's atmosphere, huh? For your craft, I was thinking 8-10 might be appropriate. Though people have been achieving success with gigantors, they're also pretty draggy, which could be your primary speed limiter. Perhaps the large fuel cells might be an easier option?

In any case, I love the your big wing design, and am pleasantly confused as to how it stays stable with the control surfaces in front. Cheers!

[DualDesertEagle]

16 hours ago, Cunjo Carl said:

Sorry it hasn't worked out so far! Those little ion engines really do a pittance for thrust in Kerbin's atmosphere, huh? For your craft, I was thinking 8-10 might be appropriate. Though people have been achieving success with gigantors, they're also pretty draggy, which could be your primary speed limiter. Perhaps the large fuel cells might be an easier option?

In any case, I love the your big wing design, and am pleasantly confused as to how it stays stable with the control surfaces in front. Cheers!

It's all a matter of center of gravity and center of lift. I also build RC planes so I know a bit about aerodynamics and stuff. One problem with KSP is that the control surfaces on a regular plane's tail add to its lift and thus u have to have the center of gravity further back in order to have it fly or add some control surfaces in front of the CG to move the center of lift where it's supposed to be. But the most basic rules are the same:

The center of gravity and the center of lift need to be close together, with the CG never being too far behind the CL, ideally being in front of it instead. The positions of CG and CL relative to each other is what makes a plane well-trimmed, tail-heavy or nose-heavy.

 

The angle of attack is what makes a plane climb or descent. A neutral angle of attack ideally makes the plane fly straight without descending or climbing, as u can see on my entry. A negative angle of attack (nose down) makes it descend. A positive one makes it climb.

 

With a stationary engine there's of course another source of lift or negative lift, which is the engine itself pushing up or down depending on its angle. The percentage of that extra lift depends on the angle of attack. At a neutral angle of attack the engine will obviously create 100% thrust and 0% lift, provided it's parallel to the longitudinal axis. If the engine is powerful enough to actually lift the craft on its own then there's a certain angle at which u get more lift from the engine than from the wings. I personally would consider that a vertical take-off. That's why I kept the angle of attack on take-off below 45 degrees to make absolutely sure I'm not more or less taking off vertically.

 

the weight to lift ratio of a plane determines how fast it needs to go to make the lift surpass the weight of the plane. My entry is a very good example for that. I chose the biggest available wings and the lightest available pod, tank, engine, wheels and canards to make my plane as slow as possible. I could take some parts off it but then I wouldn't be able to control it anymore. But putting the rest of the parts together correctly I already achieved take-off speeds as little as 5.9 meters per second. And yesterday I even had an idea how I could still reduce the plane's weight without losing much thrust.

 

Do u want a slower, more maneuverable plane, then the CG must be further back. Do u want a fast but less maneuverable plane, the CG must be a little further in the front. The reason being that the faster a plane goes with the same center of gravity, the more it wants to pitch up on its own. In KSP we can have the SAS handle that, but only to the point where the controls are maxed out. And extremely nose-heavy plane will never even take off coz it just won't pitch up to increase the angle of attack. And extremely tail-heavy plane on the other hand will TRY to take off but can't, as the angle of attack gets too steep very quickly. The plane stalls and falls back to the ground.

 

Having big lifting surfaces or control surfaces far in front of the CG makes the plane susceptible to "tipping over" as soon as the slightest pitch is applied. The bigger surface the acts like a tail fin that was pointed forwards. The smaller control surfaces in the back can't keep the plane lined up anymore as they're the weaker ones compared to the wings in the front, that's why regular planes are hard to build after real specs. Especially my Naboo Starfighter with the wings being at the very front of the craft had massive trouble with this. It was really hard to get it to fly well and that wasn't possible without adding control surfaces to the tail. But at least they don't have to be stickin' out all the way and ruin the look completely (And be honest, I did a MUCH better job on it than jacksepticeye, didn't I?):

 

Edited May 26, 2016 by DualDesertEagle

[Cunjo Carl]

@DualDesertEagle Thanks! I've been considering giving this challenge a go, so the information has been super helpful. I doubt I'll beat 10m/s, but it's the trying that's fun.

[tseitsei89]

On 22.5.2016 at 2:09 AM, DualDesertEagle said:

My entry's up:

 

Not trying to be mean here but a few things I noticed while watching the video:

1. You definitely have a vertical component in your thrust when doing your "slow takeoff" since your plane is tilted ~20 degrees up. So your engine isn't horizontal which obviously gives you some upwards thrust.

2. Also can you maintain level flight at that speed? If not, then at what speed can you maintain level flight? I thought that was the reason for this challenge but I might be wrong (Who can maintain a level flight with slowest speed while having zero vertical thrust? is how I would phrase it.)

That's all. No offense meant

 

 

[DualDesertEagle]

15 hours ago, tseitsei89 said:

Not trying to be mean here but a few things I noticed while watching the video:

1. You definitely have a vertical component in your thrust when doing your "slow takeoff" since your plane is tilted ~20 degrees up. So your engine isn't horizontal which obviously gives you some upwards thrust.

2. Also can you maintain level flight at that speed? If not, then at what speed can you maintain level flight? I thought that was the reason for this challenge but I might be wrong (Who can maintain a level flight with slowest speed while having zero vertical thrust? is how I would phrase it.)

That's all. No offense meant

 

 

1.1 Look at the screenshot I put in, 1 of the contestants said

On 4.4.2016 at 0:52 AM, Rocket In My Pocket said:

Thanks! I think I may have bent the rules a bit as it tends to fly with it's nose pointed up by about 10 degrees, which makes the engine point 10 degrees down so...sort of a downward facing thruster.

And this was the thread starter's answer

On 4.4.2016 at 0:54 AM, volcanic_wolf said:

no what I meant is no downward while level so you're fine

 

Same goes for me I guess.

 

1.2 Let's be honest, the engine I used has a maximum thrust of 16.2 (whatever unit is used in the game) and is tiny compared to the wings. Plus, take-off happens at 40% throttle (thus putting out a thrust of only 6.48 which is basically nothing for such a big craft) and an angle of attack of (let's round it up to my disadvantage) 19 degrees. Since I didn't have the right formula at hand I just made a (literal) vector graphic:

And I think that amount of downwards thrust is negligible, at least when u look at the size of the plane compared to the engine.

 

 

2.1 To me, "level flight" means going forward with no change of altitude, no matter which angle of attack is applied. So yes, by reducing the speed just a hair I could do a level flight and even achieve a slower speed than on take-off, but it's the take-off speed that was asked for.

2.2 With an engine being mounted in a fixed orientation there is no such thing as "having zero vertical thrust" as the engine will always be tilting together with the aircraft. And to get a plane off the ground u'll either need a pretty high speed or at least a slight angle of attack.

Edited May 28, 2016 by DualDesertEagle

[DualDesertEagle]

17 hours ago, Cunjo Carl said:

@DualDesertEagle Thanks! I've been considering giving this challenge a go, so the information has been super helpful. I doubt I'll beat 10m/s, but it's the trying that's fun.

Defying the arguments against my entry I completely overlooked ur post.

 

I think now that u know how I did my 8.1 meters per second the 10m/s mark shouldn't be that much of a problem for u. And that's why I'm gonna get back to it and try to even beat my current 5.9m/s record.

[tseitsei89]

25 minutes ago, DualDesertEagle said:

1.1 Look at the screenshot I put in, 1 of the contestants said

And this was the thread starter's answer

According to that answer you can just build a "plane" that has >1 TWR and take off vertically and then turn in to horizontal flight So take off speed would be ~0.0m/s

25 minutes ago, DualDesertEagle said:

Same goes for me I guess.

 

1.2 Let's be honest, the engine I used has a maximum thrust of 16.2 (whatever unit is used in the game) and is tiny compared to the wings. Plus, take-off happens at 40% throttle (thus putting out a thrust of only 6.48 which is basically nothing for such a big craft) and an angle of attack of (let's round it up to my disadvantage) 19 degrees. Since I didn't have the right formula at hand I just made a (literal) vector graphic:

And I think that amount of downwards thrust is negligible, at least when u look at the size of the plane compared to the engine.

Yes I agree that the vertical thrust component in this case was quite negligible.

25 minutes ago, DualDesertEagle said:

 

 

2.1 To me, "level flight" means going forward with no change of altitude, no matter which angle of attack is applied. So yes, by reducing the speed just a hair I could do a level flight and even achieve a slower speed than on take-off, but it's the take-off speed that was asked for.

Ok that's fine

25 minutes ago, DualDesertEagle said:

2.2 With an engine being mounted in a fixed orientation there is no such thing as "having zero vertical thrust" as the engine will always be tilting together with the aircraft. And to get a plane off the ground u'll either need a pretty high speed or at least a slight angle of attack.

Easy solution is to either:

1. Tilt your wings so that they have an angle of attack while the rest of the plane (including the engine) is horizontal

2. Tilt your engine so that it is horizontal when the angle of attack of the plane is whatever it needs to be in level flight (or at take off if we measure that instead)

 

 

But all in all I think that in your case the vertical thrust really is very small. I would just like some more accurate and better defined rules...

Again no offense towards you or anyone else meant

[DualDesertEagle]

KILLED IT! 5.8 m/s take off speed!

I think I've really pushed the limit tho, and this might aswell be disqualified since I'm taking off with well over 50% throttle and at an angle of 30 degrees.

But should this still count, ur gonna have a hard time beating it!

I've really started splitting hair to make it this far! I've taken off really EVERYTHING that wasn't ABSOLUTELY VITAL to make the plane take off, I've switched to an engine that was a whopping 10 grams lighter than the old one, I've joined the wings together in the middle and swapped the retractable gears to non-retracts of the same weight but with streamline housings to improve the aerodynamics, I've increased the dyhedral to have the plane sit on the ground at a higher angle, I've made absolutely sure that the wheels are mouted straight to minimize friction and I've taken half of the fuel out of the tank! This thing probably has the best lift to weight ratio that can be achieved and it's really just designed to take off, then run out of fuel soon after and fall back to the ground. U can't control anything but the throttle and the in this case absolutely useless thrust vectoring.