Dumpling range challenge

[zolotiyeruki]

1 hour ago, doggonemess said:

I'm interested in this, but I have a question. What is the problem with electrical storage at the start? Since there's no electric powered engines for atmospheric flight, I don't see what the issue is. I must be missing something.

On page 1, OP responded that stock propellers are allowed.  If you're not familiar with the idea, they're "propellers built out of stock components," not "propellers that are stock part."  If you search on youtube for "ksp stock propeller," you'll get the idea.

The reason for draining electrical charge before flight is to ensure that all energy for the flight comes from the one Dumpling fuel tank.

After a *whole* lot of testing and iterating, here is my second entry:

Crash landed (but mostly intact!) at 40 1/3 degrees east. 

(115 degrees/360) * (2 * pi * 600km) = 1204 km.  I made it almost a third of the way around Kerbin on less than 10 units of liquid fuel.

More pictures here:

https://imgur.com/a/VAglQ9R

[mystifeid]

So after shedding 30kg from my trike I disabled Mechjeb and tried a short run north from KSC through pretty typical grasslands terrain. It took a while to sink in but with a jolt I realized that I wasn't just more economical than MJ, I was much more economical.

Ok then. Time to pull out the big guns. Kerbals in command seats weigh more than 90kg and in my first attempt, Jeb made up one quarter of the rover mass. Plus an Okto 2 weighs 10kg less than a command seat. Even better, in an unmanned trike the fuel mass of 110kg becomes one third of the rover mass instead of one quarter.

I returned to the desert with my new 304kg rover.

And put the foot down.

I was really quite profligate with the gas yet after 100km had used just 0.48 units of LF. At the same point in my first attempt my rover had used 0.87 units of LF (For whatever reason this section is one of the most economical in the entire route).

That's a difference of 0.39 LF. Even in Jeb's rover that's enough fuel to travel 40km. But in this one??

Edited May 11, 2019 by mystifeid

[mystifeid]

A couple of things bothered me during the night. I wondered about the cause of Mechjeb's inefficiency. Was it the speed control or heading control. I could live without the speed control because it had to be micro-managed anyway but I really wanted to use the heading control. The small rovers have a fair amount of directional instability and my own heading control kinda sucked. Not to mention the tedium of tap-tap-tapping for days on end. Perhaps Mechjeb could pay for itself over a long trip by keeping me pointed in a straight line.

The other concern was the blob-like profile of the rover so I removed the probe core from the back and placed it underneath. A small nose cone weighs 10kg and placed in front of the dumpling, if nothing else, makes it look a bit meaner.

I start from the beginning again.

Subjectively it certainly seemed to go down hills quite a bit faster. After finishing with a long downhill coast last night, the first unmanned trike was stopped when it slowed to 4m/s. Today, I reached that rover still doing more than 9m/s.

The icing on the cake is that yesterday's rover used 0.48 LF for the first 100km. Today, and while using Mechjeb's heading control, I used just 0.41 LF.

I decide that this is good enough and keep going...

Rather than start with a minimum of EC, Valentina comes along to fire up the fuel cell so that I can begin with zero electricity.

Fuel cell started and Val is staged.

Meeting up with yesterday's effort just past the 100km mark.

[Tyr Anasazi]

I think I might actually have a worthy entry for this challenge - I made a hybrid plane!

For this craft I built a rotor which integrates the fairing, juno, intake and dumpling. The dumpling is one of the bearings. There is no generator except the Juno, which is set to a maximum of 2.5KN thrust. It's going to take a while before this thing runs out of fuel. Currently at 2000 altitude, 61 degrees longitude, having 6.3 (out of 9.9) units of fuel left.

The unmanned version clips along at 80m/s so should go 60% further than this one. I'll be sure to report back!

[Tyr Anasazi]

Actually - disregard my last entry - I'll get back to the Juno hybrid later but for now I will enter this one which uses a fuel cell. Something tells me it will go far!

[Tyr Anasazi]

Here is Valentina at +2 degrees longitude, 77 degrees travelled in 3 hours, 16 mins. 69% of fuel used. 

At this rate, fuel will run out somewhere between 110-115 degrees longitude - which will put this entry very close to @zolotiyeruki's record. Unfortunately I can't time warp with a prop so I must wait to see the final result..

 

[Tyr Anasazi]

Running on fumes now! Soon we will know whether or not Valentina swipes the prize! In preparation for the final glide I have prop blade controls and electricity charge handy.

[Tyr Anasazi]

Aaaand after 4 hours, 50 minutes of flight time, Valentina crash-landed just barely short of @zolotiyeruki's record. 

114,6 degrees longitude travelled, (114.6/360) * (2 * pi * 600) = 1200.08 km.....   4KM short ROFL

I suppose I can claim the manned record though

Edited May 12, 2019 by Tyr Anasazi

[Tyr Anasazi]

2nd attempt

I added larger wings and reduced the wing pitch. Now it flies 20% faster using the same energy. It's also better at gliding and landing. I predict a final distance of 1450-1500km.

Edited May 12, 2019 by Tyr Anasazi

[mystifeid]

At just over 500km with 75% fuel remaining.

[zolotiyeruki]

Nice job! Here are a few more tips for optimizing it: 2-3 degrees is the optimal pitch for efficiency, and the optimal amount of lift is about 1 unit of lift rating per ton of (total craft) mass in my experience.  Most wings and wing parts have 1 lift rating per 100 kg, and control surfaces are worse. The smallest winglet is an exception: it gets 1.2 per 100kg, making more than usually efficient. You may be better served by using a reaction wheel for control rather than control surfaces, to reduce mass.

Edited May 12, 2019 by zolotiyeruki

[Tyr Anasazi]

Attempt No 2 failed because I went to bed, and during the night Val crashed at +43 longitude. I won't count it as an entry because I don't know what happened, and I didn't take a screenshot. 

So without further ado, here is an image from attempt No. 3. Val settles in for a long night on the Light & efficient plane MK3:

[Tyr Anasazi]

This picture makes me angry. After flying for nearly 4 hours I went to get some dinner and when I returned to my computer Val had crashed again. Fortunately she survived.

I am disappointed because I planned a controlled glide & landing of this craft.

FInal landing point was just under +56 degrees longitude, which means

131 degrees longitude travelled, (131/360) * (2 * pi * 600) = 1371 km. A new record!




HOWEVER: Seeing as I didn't land properly, there is only one thing to do and that is Attempt #4!

This time I am trying a higher altitude, currently cruising at 6.3 km altitude, at 105 m/s. Val was enthusiastic at takeoff:

[Tyr Anasazi]

Fourth time's a charm! The Light & Efficient Plane (LEP) MK3 worked well and was brought down to a soft landing in Valentina's skilled hands.

Some quick details about the craft:

• 1.7 tons
• 53 parts
• 110m/s max cruising speed at 7000m
• 4+ hours endurance at max cruising speed
• All power storage 100% drained before flight
• Fuel cell powered propeller plane, using 1 dumpling tank for fuel
• Driven by a single large reaction wheel

Hitting F3 gives 2,515 km ground distance travelled however the actual distance is less as has been stated above.

Start longitude: -75 degrees (KSC runway)
End longitude: +69.57 degrees
Total longitude travelled = 144.57 degrees
(144.57/360) * (2 * pi * 600) = 1513.9 km

Gallery of images from this flight:
https://imgur.com/gallery/eNd41A9

Craft file:
https://kerbalx.com/Tyr_Anasazi/Light--Efficient-Plane-LEP-MK3

[zolotiyeruki]

Nice.  I've not really delved into stock props at all, so I don't have much else to suggest, other than shrink that part of the craft in order to reduce your drag and mass.

[mystifeid]

After just 21 hours the little trike completes the 1010km to the North Pole with half a tank of gas remaining.

 

[mystifeid]

Since it appeared to be impossible to continue for another 1000km in a straight line, the best idea seemed to be to simply turn around and head for home - back to the Dessert Airfield.

After a big day, the little rover is back at the 40th parallel (50 degrees traveled today). So far it has covered 146.5° or 1534km. A little over a quarter of my fuel remains with my goal still around 480km distant. Whatever happens, it will be close.

 

Looking for an alternate route back through the tundra: the usual long white-knuckle rollercoaster ride down from 800m taken on the outward leg seemed like a bad choice for the return. I settled on an exit from the ice shelf just left of center in the screenshot and it provided a dream run through the tundra.

 

Hooking into it near the start of the grasslands.

 

There is a big doubt here about whether the other side of the river crossing will be possible. It has always seemed steeper...

 

After the 3 m/s creep down to the bottom of the gorge.

 

Success. A 32° incline is no match for the rover. (Try alternately tapping the left and right keys while holding the forward key if ever in this situation).

[mystifeid]

Wow, again. The trike made it back to the Dessert Airfield with a little under 5% fuel remaining - despite my best efforts to use as much as possible from a long way out. It continued south until veering south-west to miss the wet stuff before following the coast southward again.

Finally, after 45 hours and 15 minutes, it ground to a halt with all fuel and energy depleted. Total distance covered - 2128km.

Fastest speed - 37m/s.
Highest elevation - 1447m.

Distance Outward Leg

Start Latitude - 6° 33' 36" S     Finish Latitude - 90° N     Sub-Total - 96° 33' 36"

Distance Return Leg

Start Latitude - 90° N     Finish Latitude - 16° 41' 51" S    Sub-Total - 106° 41' 51"

Total Degrees - 203° 15' 27" or 203.25°

Total Distance - (203.25/360) x 2 x pi x 600km = 2128km

Everyone has come for a piece of the little trike.

The Wheeled Automaton Society was out in force after proposing a new unit of measurement - the "Dumpling" - to replace that unfortunate collection of words - two thousand kilometers. They imagine it will have all sorts of useful applications.

Picture it. The kids ask "Are we there yet?"
The modern Kerbal gives a wry grin and replies "Are you kidding? There's still half a dumpling left to go."
"Did you say dumpling? Ooo, we're hungry."
"Good. I'm tired. Let's stop for the night."

Or - "What sort of orbit are we aiming for?"
"Fifty dumplings."
"Reminds me. You gonna remember to pack the snacks this time?"

"Help. Fuel is bzzz crackle..."

 

A certain amount of impatience dictated courses over obstacles that would otherwise have been avoided. How bad could those mountains be anyway?

 

Looking back at the fairly obvious route through those mountains afterward.

 

The highest point reached (by far) in the entire trip - 1447m.

 

Three times I crested sharp ridges at extremely slow speeds and just started tumbling - the rover rolling three, four and even five times before, miraculously, finding it's legs again.

 

Looking back at the mountains. Coasted from this point for something like 23km - at speed.

Edited May 15, 2019 by mystifeid

[Tyr Anasazi]

@mystifeid what you achieved with that little rover is very impressive - and proves that fuel cells are the way to go when it comes to efficiency. 2128km in a rover is further than any of us have managed in an aircraft.

Having said that... CHALLENGE ACCEPTED! 

Here is Val at the controls of LEP MK4. She has to wear her helmet because this prototype cruises at more than 13000m, averaging 172m/s. Endurance is unchanged so assuming an uneventful flight, Val will travel at least 2500km, about 2/3 the distance around the planet.

At this point I am trying to find ways to make LEP reach higher speeds. Endurance is fixed at approximately 4.25 hours, so every additional m/s adds about 15.3km to max range.

If I can reach 246 m/s, then LEP will circumnavigate Kerbin on a single Dumpling

[Tyr Anasazi]

@mystifeid I think I will take a cue from your storytelling style

...As night falls, Val checks her instruments and settles in for a long night cruise. Her space suit protects her from the thin, minus 55 deg.C air. Without her helmet, she would instantly suffocate and freeze. She feels a hint of nostalgia for earlier flights where she could fly with her hair in the slipstream.

 

Val cannot resist turning her gaze upwards, towards the milky way which fills the dark sky. Glancing back down to her instruments, she notices that the aircraft is cruising comfortably at 174 m/s, completely level at 13.1km altitude. For a moment she wonders if LEP might be a contender for the propeller powered altitude record as well. What else was this craft capable of? Her engineer's brain inevitably turns to calculations. Circumnavigation of Kerbin? Addition of ion thrusters for a hyper-efficient SSTO? atmospheric flight on other planets? Mentally visualising complex equations, She keeps her active mind occupied through the long night...

(to be continued)

[Tyr Anasazi]

The vast panorama of space fades as the first light on Kerbin's horizon becomes visible. Val squints into the new day, anticipating what she will achieve on this flight.

 

Even though she knew before takeoff that this flight would far surpass the record she set in LEP MK3, Val feels a rush of excitement as she flies past her previous landing point at 69.57 longitude. LEP MK4 is cruising high and fast.More than 1500km distance has been flown, and more than a third of the fuel remains. "Let's make it count" thinks Val...
(to be continued) 

 

 

[Tyr Anasazi]

Disaster strikes!

Just as LEP MK4 reaches the open ocean and is on its last leg to beat all records, it suffers a catastrophic engine failure. Val fails to notice that as the dumpling tank weight decreases, LEP slowly inches its way to higher altitude, resulting in the engine spinning faster as air resistance decreases. Vibration suddenly increases and the experimental powerplant rips itself right off its bearings. Val,  thrown violently from her seat, begins freefalling to Kerbin. Val's view of of LEP MK4's spinning, twisted wreckage fades to black as she loses consciousness...



Fortunately, Val regains consciousness at 1500m altitude,  just in time to deploy her parachute. As she glides gently down to the Ocean surface, she activates her emergency beacon. As she descends towards the waves, Val reflects on how fortunate it is that her spacesuit is positively buoyant, and that she packed some emergency rations in a side pocket. It might be a while before rescue teams arrive. One thing was certain, thought Val. It would not be long before she was back in the air for the next attempt! Next time, she would be sure to keep a closer watch on engine RPM...

[mystifeid]

2 hours ago, Tyr Anasazi said:

What else was this craft capable of? Her engineer's brain inevitably turns to calculations. Circumnavigation of Kerbin?

I hope you get there. For myself all I can say is - Never Again!!

[Tyr Anasazi]

An update from the Dumpling testing grounds 

After Valentina's close brush with death in LEP MK4, Val went back to the drawing board, determined to return to the skies in a vastly improved Light & Efficient Plane. Her goal - that LEP MK5 must be able to circumnavigate Kerbin on a single dumpling tank!

When Val's colleagues Jeb, Bill & Bob arrived in a rescue hovercraft to pull her from from the ocean, she warmed her hands on the mug of hot chocolate they gave her, and told them  her plan. After a moment of stunned silence, they broke into wild laughter. "Impossible!" said Bob. Their scorn only hardened Val's resolve. Back at KSC, she knocked on Dr Wernher Von Kerman's office to show him the equations she had scrawled on the back of a kerbonaut ration wrapper during her unsuccessful flight. Some of the equations were smudged as the wrapper was still dripping wet from Val's unplanned swim in the ocean. His brow furrowed in concentration, Dr Von Kerman examined the equations, took a few notes of his own, murmured gently, finally nodding and looking up. "Valentina, I think you may be on to something. If successful, it will be a Kerbin first for sure. Project approved!" 

Not wanting to waste any time, Val put got her development team straight to work. All data collected from the flights of LEP MK1, 2, 3 and 4 was collected and analysed, and brainstorming sessions were held where all ideas could be put forward on how to make LEP MK5 the most efficient and long range plane that ever flew. "Also" quipped Val - "it would be nice if it's a bit more reliable than the previous models. I'm not a particularly good swimmer."

In order for the single reaction wheel powerplant to carry LEP MK5 all the way around Kerbin, the plane would have to reach an average speed of 246 m/s. This proved an elusive goal, because reaching this speed required drastic reduction in drag, and more power to somehow be squeezed out of the engine, without sacrificing efficiency. The program took longer than usual, and at several points Val almost gave up. The target speed seemed just impossible to reach! Then, on what was perhaps the hundredth test flight, Val flew the LEP MK5 prototype at just over 246 m/s, in level flight!

Val had to do a double-take as she looked down at her airspeed indicator. "This plane's nickname shall be the Global Dumpling" she thought with a smile, as she turned the plane back to land at KSC. LEP MK5 was nearly ready for its record flight...
(to be continued)

Edited May 18, 2019 by Tyr Anasazi

[Tyr Anasazi]

Ladies & gentlemen, you may have heard of the Global Hawk. Today I present to you Global Dumpling MK1.  

As its name suggests, this aircraft is capable of circumnavigating Kerbin, using the contents of a single dumpling fuel tank as its only source of energy. The circumference of Kerbin is 3,769.9 km.

GD MK1 is the end result of the Light & Efficient Plane (LEP) program, which was undertaken in order to compete in the prestigious "Dumpling Range Challenge". It combines the raw efficiency of fuel cells, a lightweight yet powerful motor, and a low-drag, high altitude airframe design.

GD MK1 has a burn time of 4 hours and 4 minutes. the first 10 minutes are spent gaining speed and height. At 12,350m altitude, GD MK1 cruises from 250 to 254m/s. By the time fuel is expended, GD MK1 travels just under 3600km. From there, it easily glides the remaining distance to touch down at KSC.

GD MK1 is currently cruising on its proof-of-concept circumnavigation flight, with Valentina (who else) in the cockpit. 

 GD MK1 flight stats (as of writing):

• Altitude: 12,387m
• Airspeed: 254.5 m/s
• Flight time:  1 hour, 34 mins
• Distance travelled: 1354km
• Distance remaining to KSC: 2415km
• Liquid fuel remaining: 5.95/9.9
• Estimated remaining burn time: 2 hours, 30 mins
• Pilot status: 

 

 

Edited May 19, 2019 by Tyr Anasazi