SSTO R.A.P.I.E.R. (Ver 0.23) Challenge (Closed)

[Sun]

The R.A.P.I.E.R. engine is too heavy for me to get it off the ground plane-style.

[koshelenkovv]

The R.A.P.I.E.R. engine is too heavy for me to get it off the ground plane-style.

It weights only 1.75 tons, not much more than jet.

The plane depicted in previous post can take off at 30 m/s.

[g00bd0g]

An evening of tinkering yielded this design. Reminded me of a f-104 starfighter, hence the name. I am 99% sure my math is correct but I welcome some double checking. Not included in the video is the circumnavigation of Kerbal and a perfect touchdown at KSC

Name: StarFighter

Part Count: 13 ((150-13)*10= 1370)

Time to LKO: 9:16 MET ((10-9.16)*5=4.2)

Fuel Remain: 127 ((127/10) * 3 = 38.1)

Total score: 1412.3

Craft File: https://drive.google.com/file/d/0B4zLBUio4kInVm0wdDd0ZzRYUG8/edit?usp=sharing

Edited December 31, 2013 by g00bd0g

[Sirine]

@koshelenkovv Nice craft.

@g00bd0g Nice craft. I thought 15 is the limit...and you bring in 13...with only "control surface" as wings..that should be the minimal as..."air plane". Its walking the line of...."rocket with wings" rules. However, I will still add you to the leader board. And a job well done. I have try to land your craft..and surprisingly success, but not without issues, the main issues was not the lift...it is the battery...

Edited December 23, 2013 by Sirine

[XolotlLoki]

Introducing the Fly, a minimal SSTO using the new Rapier engine.

It places 3rd according to the current leaderboard:

• Craft Name: Fly
  
• Part Count: 14 ((150 - 14) * 10 = 1360)
  
• Time to LKO: 7:29 MET ((10 - (7 + 29/60)) * 5 = 12.58)
  
• Fuel Remain: ((29.6 / 10) * 3 = 8.88)
  
• Total score: 1381.5
  
• Craft file: here.
  
• 
  

I also noticed that the current #1 and #2 are not calculated correctly, since 9:16 is not the same as 9.16. The actual scores should be:

((150 - 13) * 10) + ((10 - (9 + 16/60)) * 5) + ((127 / 10) * 3) = 1411.76

and

((150 - 12) * 10) + ((10 - (7 + 39/60)) * 5) + ((20 / 10) * 3) = 1397.75

The error was small enough that the relative positions did not change.

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[XolotlLoki]

Now that I've posted my entry, I'm starting to review the others, beginning with the leaders.

The link for the #1 entry does not work, so I cannot test that: https://drive.google.com/file/d/0B4z...it?usp=sharing (probably a copypasta problem with the ...).

The link for #2 did work, and I was able to open the .craft file. However, the entry did not contain a docking port, so I believe it should be disqualified. I will also try to fly it, but given the lack of lift I fear the landing will be brutal

EDIT: landing was indeed brutal as expected; I never managed a single landing in almost a dozen tries. Even at full throttle I needed almost 20* AoA to maintain level flight at 150 m/s, which basically makes it impossible to land. With less then full throttle the plane drops out of the sky.

But even takeoff was non-trivial with the Gnat. The front landing gear was so much higher than the rear that the plane was at 10* AoA while taxiing. This caused serious instability as the plane accelerated, which lead to a roll over crash every time. The only way to manage takeoff was to constantly pitch up, which provided an even down force that somehow stabilized the plane until it got to the end of the runway.

I'll update this post as I test more planes.

Edited December 27, 2013 by XolotlLoki

[Sirine]

Now that I've posted my entry, I'm starting to review the others, beginning with the leaders.

The link for the #1 entry does not work, so I cannot test that: https://drive.google.com/file/d/0B4z...it?usp=sharing (probably a copypasta problem with the ...).

The link for #2 did work, and I was able to open the .craft file. However, the entry did not contain a docking port, so I believe it should be disqualified. I will also try to fly it, but given the lack of lift I fear the landing will be brutal

I'll update this post as I test more planes.

Welcome XolotlLoki.

-The #1 link has been fixed.

-The #2 docking port issues does exists, gray-out from the leader board. (If Col_Jessep does not fix this problem, his entry will be remove as at 31-Dec-2013)

-The calculation for "times" of MET, as all of us already using the .10 decimal, and since everybody calculating the same way, it is fair to everybody. Although it is definitely 'wrong' calculating time in this way. But.... well, you come in too late.

And nice entry for your 'Fly'. (You may submit multiple entry.)

[XolotlLoki]

Welcome XolotlLoki.

And nice entry for your 'Fly'. (You may submit multiple entry.)

Thank you Sirine, it's a pleasure to take part in your challenge. The numerical scoring gives a very different experience from the BSC challenges; it's easier to optimize for the win, though at the risk of losing the intangible attributes. That's why I'm focusing on simple takeoff/manuever/landing tests. Basically, I takeoff, do some form of cuban-8 to get back to the runway, then land. Then I do it again, but run the engine in rocket mode to drain the oxidizer and most of the fuel before landing. I do the full tank landing with full throttle, but try to do the empty tank landing with no throttle. This simulates both a launch abort and also a return from orbit, which are the only real use cases for SSTO landing.

With the fixed link, I was able to test the current #1, goobd0g's StarFighter. Though similar to The Gnat in basic structure, it was a much more pleasant plane to fly. The front gear height differential was very modest, only giving about 3* up attitude on the runway. This allowed a normal takeoff, though the front placement of the rear gear allowed over-rotation and tailstrike if you are careless. I even managed a powered landing with full fuel tanks, in spite of the 15* up attitude necessary to maintain level flight. I was unable, however, to land unpowered with empty tanks. There just isn't enough lift in the wings.

Overall, StarFighter is an excellent implemetation of the mini-wing design, and well deserves its first place.

[tntristan12]

Here's my entry! 91 parts; 33.15 tonnes.

EDIT: Derp. Didn't read the OP carefully enough. My craft only has 32 units of Monoprop (but it does have full docking capability).

EDIT2: I use small cubic struts too. Not sure why that's forbidden, but oh well. Guess I'm out!

Edited December 27, 2013 by tntristan12

[Sirine]

@ XolotlLoki I was able to land it too...just not that 'undamage' type. But well, if I careful enough. I believe I can land it in 1 piece. Just...the electricity drain out before I can properly land it.

@tntristan12 Welcome. Looking forward for your entry.

NOTE:

Challenge guideline.

2) You must start from the runway. Liftoff horizontally and able to land horizontally.

Edited December 27, 2013 by Sirine

[Sirine]

@XolotlLoki I was thinking about part 2 for this challenge. All basic rules remain the same. With some twitch on the scoring site.

Lets say:-

1) Less part. (1 points each part less)

2) Fastest times to get to LKO. (10 points for every 1 minutes less: Max 10 minutes: after 10 minutes 0 marks.)

3) Fuel remain. (5 points for every 10 units of fuel left)

Will that be interesting ?

It will totally revise the engineering design part.

Edited December 27, 2013 by Sirine

[g00bd0g]

@ Sirine @ XolotlLoki I was able to land it too...just not that 'undamage' type. But well, if I careful enough. I believe I can land it in 1 piece. Just...the electricity drain out before I can properly land it.

I had to "cut the main power" from the command pod and use it sparingly just to complete the necessary orbital maneuvers. The plane flies OK in atmo without electricity as the aero controls still work. I do turn all systems on for final approach and touchdown.

[ZingidyZongxxx]

7) Cubic Octagonal Strut, Octagonal Strut, Modular Girder Segment, M-Bean 650 I-Beam, and BZ-52 Radial Attachment Point are forbidden to use.

Why are these parts forbidden? I already have an SSTO, but I'm pretty sure it uses some of these.

[RocketTurtle]

I think because it's supposed to be noob friendly.

[XolotlLoki]

Lets say:-

1) Less part. (1 points each part less)

2) Fastest times to get to LKO. (10 points for every 1 minutes less: Max 10 minutes: after 10 minutes 0 marks.)

3) Fuel remain. (5 points for every 10 units of fuel left)

Will that be interesting ?

I think that would be very interesting for part 2. It completely changes the optimizations, and without the extreme need to lower part count we should get much more creative designs.

[XolotlLoki]

Continuing my reviews of the leaderboard, I flew Mesklin's Omega and ABalazs' XR-5SB.

Omega was an interesting design. The large delta wing and widely spaced gear made takeoff and powered landing relatively easy, and there wasn't too much runway AoA (maybe 3*). However, the lack of a tailfin (and hence yaw control) made unpowered landing difficult, and I was unable to do the last second corrections necessary to land on the runway.

XR-5SB was actually very pleasant to fly. The only real problem was the wide wings and narrowly spaced gear, which caused several wing strikes during powered landing. It used the same V-tail as my Fly, which provides a good balance of low part count and aerodynamic control. It did have a somewhat large runway AoA (like 8*), but this didn't interfere with takeoff or landing; it allowed takeoff rotation before the end of the runway, which is not common.

Next I tried to download Slugywug's Minimal SSTO, but the link 404'd. Darren9's gRape'r downloaded, but it didn't include a cockpit or a remote pod, so no way to control it. I skipped Col_Jessep's second entry, and went on to Xeldrak's CRAP.

CRAP was a very good mini-wing design. The X-tail was a nice touch, and gave a surprising amount of lift, which most mini-wing designs lack utterly. This allowed full-tank powered landing with only 1/3 throttle, which no other mini-wing could do. However, the X-tail had one major drawback; the lower two fins were dangerously close to the ground, and broke off in almost all of my landing attempts. This was made worse by the excellent roll control they provided, which made it difficult to stay exactly roll-neutral during landing approach. And when I did manage a perfect touchdown (after 5 tries), applying the brakes made the plane front-flip and crash. Still not sure why that happened.

I skipped ABalazs' second plane, and SkyRender's RCS-free plane. I did test Hodo's X-152A and Liowen's Tadpole MK1R.

X-152A was in many respects a nice plane. However, the large canard caused unstable pitch control which frequently made the plane fly backwards. This was somewhat mitigated by the CoM/CoL, which allowed a relatively easy switch back to prograde. But it rendered my flight plan untenable, and I was forced to actually turn around to get to the runway, not use some kind of cuban-8. Though the powered yaw control was excellent, I still crashed trying to get on the runway.

Tadpole was a very large plane for this challenge. It flew very well with tanks full; I managed a clean powered landing with both 1/2 and 1/3 throttle. However, with tanks empty the CoM had shifted behind the CoL, and I crashed badly on landing.

Edited December 28, 2013 by XolotlLoki

[Horn Brain]

Why can't we use all of those structural parts? They're only cheaty if you use them as major structural components. I only use them to attach things to surfaces. How else do I get the stupid jet fuel adapters to attach to the rocket fuel tanks without looking weirdly off-center?

Example:

[Sirine]

@XolotlLoki I would like to hear some review from my craft too.

@Horn Brain Engineering is part of the challenge. Rules is rules. I don't think that without those structural parts your craft can't achieve orbit.

As of this post, you got 1 more day for challenge submission, after this. There will be part 2.

[Hodo]

X-152A was in many respects a nice plane. However, the large canard caused unstable pitch control which frequently made the plane fly backwards. This was somewhat mitigated by the CoM/CoL, which allowed a relatively easy switch back to prograde. But it rendered my flight plan untenable, and I was forced to actually turn around to get to the runway, not use some kind of cuban-8. Though the powered yaw control was excellent, I still crashed trying to get on the runway.

Thank you for that review, I will take a look at it and see if I can improve on the control problems a bit more. I rarely mess with stock parts so it is a bit of a challenge for me.

EDIT- I just checked the craft, it isn't as twitchy as thought, are the control surfaces set like this?

Canards-Roll

Large Control surfaces on the wings-Pitch

Tail-Yaw.

Edited December 30, 2013 by Hodo

[XolotlLoki]

@XolotlLoki I would like to hear some review from my craft too.

I didn't realize that you had actually posted a craft, but then I saw that the example entry had a working link. So I downloaded RAPIER SSTO and put it through my test plan.

Your plane was extremely pleasant to fly. Takeoff used very little runway, due to the massive amount of lift. I was able to land with full fuel tanks with zero throttle. No other plane came close to this. The plane was very controllable.

However, once I ran the closed cycle to drain the oxidizer and most of the fuel, the plane became somewhat difficult to fly. High AoA caused the plane to fly backwards, probably due to the CoM shifting behind the CoL. I was able to recover, and even landed on the runway, but there were a couple of close calls while manuevering back for landing.

I then did an SSTO run using my normal SSTO flight plan, and made it to 72km circular orbit in only 6:28, with 27 fuel and 38 oxidizer remaining. I will try to get back to KSC with the remaining fuel. EDIT: I misjudged the amount of drag, and didn't make it back to KSC. But once I got to the lower atmosphere, I was able to glide a good long while.

Your large wing and 3-engine design worked very well, modulo the CoM issues with low fuel.

Edited December 30, 2013 by XolotlLoki

[Sirine]

I didn't realize that you had actually posted a craft, but then I saw that the example entry had a working link. So I downloaded RAPIER SSTO and put it through my test plan.

Your plane was extremely pleasant to fly. Takeoff used very little runway, due to the massive amount of lift. I was able to land with full fuel tanks with zero throttle. No other plane came close to this. The plane was very controllable.

However, once I ran the closed cycle to drain the oxidizer and most of the fuel, the plane became somewhat difficult to fly. High AoA caused the plane to fly backwards, probably due to the CoM shifting behind the CoL. I was able to recover, and even landed on the runway, but there were a couple of close calls while manuevering back for landing.

I then did an SSTO run using my normal SSTO flight plan, and made it to 72km circular orbit in only 6:28, with 27 fuel and 38 oxidizer remaining. I will try to get back to KSC with the remaining fuel.

Your large wing and 3-engine design worked very well, modulo the CoM issues with low fuel.

Thanks for the review. Very much appreciate that. I will check on the CoM issues while low fuel...(Always left that out...lazybones strike)

[Darren9]

Continuing my reviews of the leaderboard,

~snip~

Darren9's gRape'r downloaded, but it didn't include a cockpit or a remote pod, so no way to control it.

~snip~

Hi mate, it has a command seat. You'll need a Kerbal in EVA next to the runway before it's launched and walk him up to the craft and board it. I saved it with the front wheel retracted otherwise it rolls away and it's quite hard to chase it with the Kerbal who needs to board it. You should lower the landing gear before attempting take-off

[XolotlLoki]

Hi mate, it has a command seat. You'll need a Kerbal in EVA next to the runway before it's launched and walk him up to the craft and board it. I saved it with the front wheel retracted otherwise it rolls away and it's quite hard to chase it with the Kerbal who needs to board it. You should lower the landing gear before attempting take-off

I tried to do this a couple of times, but the game wouldn't let me launch a plane with a Kerbal next to the runway. It kept giving me the choice to recover the Kerbal, or abort the launch. I tried from both within the SPH and the Space Center runway itself, the latter of which also gave me the option of controlling the Kerbal.

Maybe a Kerbal on a rover? EDIT: by launching your plane from SPH, then a crewed rover from VAB, I was able to get a Kerbal to your ship. But I was completely unable to get him on the ship. There was no ladder, so I tried going from the front via the intake, and from the side via the gear bay, but no luck either way.

How exactly did you test your plane?

Edited December 30, 2013 by XolotlLoki

[inigma]

Heh, could I submit this one for an under-challenge? I know it doesn't fit all the rules, but it works! Prob one of the best RAPIER SSTOs designed to date (at least I think so) Enjoy!

Forum Thread: http://forum.kerbalspaceprogram.com/threads/64159-SSI-Proton-Class-Shuttlecraft-%28Minmus-Return-Sport-Utility-Shuttlecraft!%29-VIDEO

I think it clearly violates Rule 2 because it only has 40 RCS fuel to save weight, and Rule 7 as it uses several cubic struts to hide engines within the tanks, but hey, I think the trade offs were worth it as it can go to Minmus and back! It's also is technically a VTOL, but anyways...let me know what you think!

Edited December 30, 2013 by inigma

[Darren9]

I tried to do this a couple of times, but the game wouldn't let me launch a plane with a Kerbal next to the runway. It kept giving me the choice to recover the Kerbal, or abort the launch. I tried from both within the SPH and the Space Center runway itself, the latter of which also gave me the option of controlling the Kerbal.

Maybe a Kerbal on a rover? EDIT: by launching your plane from SPH, then a crewed rover from VAB, I was able to get a Kerbal to your ship. But I was completely unable to get him on the ship. There was no ladder, so I tried going from the front via the intake, and from the side via the gear bay, but no luck either way.

How exactly did you test your plane?

Yep, it's quite a pain getting a Kerbal to a command seat only vehicle in the recent KSP's. Launch a one man pod from the SPH, EVA the Kerbal and walk (hold shift to run) him off the side of the runway (must go off the edge down the slope to the flat ground), go to command center and recover the pod (not the Kerbal). Launch the gRape'r from SPH (I saved it with landing gear retracted, for me it launches with the gear up and the seat is low enough to enter from the side, you may need to set the landing gear to raised in the SPH - I'm not sure), switch to the Kerbal, run back to the ship, hop on, put the gear down and go. I only launched/flew it twice, the first time it had no battery and an RTG won't directly power reaction wheels so I failed leaving the atmoshere. The second launch (with battery added) I made the necessary orbit for the challenge, the 10 to 20 units of fuel it should have left is enough to catch the atmosphere and effect a landing. It wasn't necessary to demonstrate a successful landing for the challenge, CoM is roughly in the center of the single fuel can IIRC so if it can take off it can land? (may require a lot more skill though ) Edited December 31, 2013 by Darren9