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Exploring The System - A design tutorial campaign 0.90 Final


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No takers for the KVV pictures then; saves a load of work.

Anyone wondering just how optimised Fat Sally is may care to look at LightMun F in the Mun Challenge thread. That's my mass-optimised Apollo-style vehicle (separate 'command' and 'lander' modules) and is 4.673t including the launch vehicle - 312kg lighter than 4.985t Fat Sally on its own! (It also manages 78kg lighter than 4.751t Long Tom)

You will appreciate why I said in the introduction "Optimised designs tend to be hard for beginners to build".

Edited by Pecan
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  • 4 weeks later...

This is a great piece of work. As a beginner I have mostly followed it through. However, I have found some problems with your Orbital SP design in the latest version of KSP. The .craft file works as specified, but the stock parts are different, so that the same design cannot be easily reconstructed by a reader. At least these things are different:

  • The old Mk2 Fuselage is now called the Mk2 Liquid Fuel Fuselage. Crucially, the part’s mass and fuel capacity have been modified.

  • The old Mk2 Cockpit is now called the Mk1 Inline Cockpit.
  • The old Small Control Surface is now called the Elevon 4.
  • Various parts (at least the Delta Wing and Elevon 4) have changed models, so that your pictures aren’t 100% representative.

Due mostly or entirely to the fuselage change, the total mass of the craft is 12.3 tons instead of the quoted 9.8 tons. I wasn’t able to get it much higher than 15 km on jets.

Also, it was while trying to construct this craft that I first had a need to manually rotate parts in the editor with WASDQE, and I did not at first realize that this function was even available, so I had to do some confused searching. A brief mention about this would be great, especially when you have the cubic octagonal struts placed. (I believe you rotate them so they clip inside the fuel tank, but do not explain this technique.)

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Thank you for your detailed comments. Strange that I haven't noticed that - must have just taken the 'plane as it was and made sure it still flies. It could do with being replaced anyway; but 0.90 will probably bring many changes. Editor changes will be particularly significant so I'll have to review any actual building tips as well.

Use Crew Shuttle Mk2 instead of Orbiter SP if you're having trouble. It's better in every way, although a little more expensive. Hope you get on OK with the rest of the campaign.

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  • 2 weeks later...

0.90 compatibility testing started - expect an update on the 22nd.

Now KSP's in Beta and this thread is almost a year old this is the last update I intend to make using the current mission/ship structure.

This tutorial was always intended to be one of a set and it's time to get on with the others. In reading order the outline so far is:

  1. Induction To Construction - Total beginners' guide to starting KSP, what the game modes and KSC buildings are, what the solar-system looks like, basic vehicle construction (where the 'Prologue' vehicles come from).
  2. Exploring The System - Beginner-to-intermediate sandbox guide to vehicle and mission design (this remodelled - prologue shortened, system-wide infrastructure expanded).
  3. Career - Intermediate; contracts, money, science, reputation, strategies, crew.
  4. World Of SSTO (With Wanderfound) - Single Stage To Orbit masterclass - SSTO rockets, VTVL jets and spaceplanes.

Comments?

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Hey Pecan!

Thanks much for your guide! After playing around in career mode for a bit, with many reverts and crashes, looking over your tutorial taught me one thing; My rockets are rather inefficient! I don't like asparagus staging, (Call it realism if you will.), so I tend to stick to a normal stacked rocket, with radial boosters. I generally only got about 5-7% payload.

Going through your guide is certainly helping me a lot!

I do wonder about the tractor; what is the reason for the LV-N engines? The four of them only give 969 dV. If I slap on a LV-T30, I can get 1769 dV, wouldn't that in the end be more efficient?

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I'm glad you are getting help from it. Remember - ideas and inspiration for your own style of play are far more important than the specific designs I use.

That said:

Yes, your rockets are rather inefficient! A minimum acceptable for most rockets should be 10% payload-ratio (those in Chapter 3 are awful, but there to demonstrate staging rather than performance), with 15% being a reasonable design expectation. With practice you should be aiming for 17-18%, although the practical maximum is about 20%.

Asparagus is a matter of taste that has caused many (genteel) rows in the forums. If you are trying to optimise payload ratio it is provably the way to go. That said, I rarely use it now because I prefer part-count optimisation (I have an old computer). Bear in mind that there are many things you'll need to avoid in KSP if you care about realism - any sort of spaceplane, jet, nuclear and ion engines, etc. Stock KSP technology, physics and aerodynamics are only 'like' Earth things; you may want to try the FAR, KIDS and DRE mods.

All the launch vehicles I'm currently using for my own missions are SSTOs; mainly VTVL-jet or rocket based because fuel is cheap and I can't be bothered to mess around in the atmosphere for ages with spaceplanes.

I use variations of the Tractor Light design almost all the time in space - if you're only getting 969m/s deltaV have you got the fuel lines attached, the right way around (from the central tank to the ones on the outriggers)? As listed it should give 3.5km/s! Here's the thing about engines; ISP. The LV-Ns have an ISP of 800, the T30 has 370. What that means is that for the same total deltaV of the LV-Ns you'll need to carry twice as much fuel for the T30 so, for longer burns and/or heavier payloads, (LV-N + fuel) < (T30 + fuel + fuel). Worse than that the fuel has mass too, which takes deltaV to push so you need more fuel, to push the double-load of fuel, making it more like (T30 + fuel + fuel + (fuel/nnnn)). Four LV-Ns is a big mass to haul around, performance would be best with just one - or even just one Ion engine! - but TWR would be minute and burn-times very, very long (which brings a whole new set of problems). Tavert's mass-optimal engine charts will tell you which is best but essentially, it's ions or nukes in space or carry lots and lots of fuel.

Hmmm, I've just checked the Tractor Light and discovered two things; i) in 0.90 MJ doesn't update with/without the fuel lines, ii) more importantly for you, in 0.25 I get over 1,710m/s deltaV even without them so I don't know why you're only getting 969m/s.

As it stands swapping the four LV-Ns for two T30s (to keep the centre 'stack' free for payload) and adding the extra fuel does give better performance - which is fine for working within Kerbin's SOI and without a payload. When you want to go further though attaching a jumbo orange fuel tank to the LV-N version gives 8.7km/s deltaV and Mun TWR of 2.42. With the T30s I ran out of height in the VAB after attaching 7 jumbo tubes - for a paltry 7.3km/s (Mun TWR 0.99). Put that together with the purpose of the tractor - which is to haul other stuff around - and you are saving an awful lot by using the efficiency of the LV-Ns. Looking at the same thing from the payload point of view - Tractor Light with 4 LV-Ns can take a full orange tank to Mun orbit as it is, with 2 T30s it requires additional X-200 8 AND X-200 16 fuel tanks for approximately the same deltaV.

Edited by Pecan
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Wow.

That answer is a lot better then I was expecting!

First things first then; I will stand corrected on your tractor light - It turns out that KER had the 'atmospheric' setting on. Without it I see a dV of 3522 m/s, mistake on my part! I need to make it a habit to stop using KER for dV, as MechJeb lists it on one page (And both of em has features the other doesn't have.....)

Your explanation on what ISP means in plain language clears a lot up, the KSP wiki wasn't too helpfull on that. Based on that, I'll stick with the LV-Ns

Your post did give me the motivation to work on the efficiency of one of my self designed rockets, which I designed to bring a 4.4t communications sattelite into gsynchronous orbit for RemoteTech. When calculating the total payload ratio, I did include the 3rd stage, which was 2.4t, I figured that because this last stage transfers my sattelite into the synchronous orbit, it technically isn't part of the actual launch vehicle.

I ended up using <this> post for some guidance, although I didn't use asparagus staging. With a 6.8t payload, I came up to a maximum of 55,5t. Calculating the rest, using a TWR of 1.6 I came to about 870kN, which I got with a skipper and LV-T30. Using the remaining weight for fuel I got to 6206 dV, and a total weight of 51.982kg, 13.1%!

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Taverts are interesting! For small payloads of around 10t I usually stick to a skipper as a first stage, with an LV-T30/45 for the second. Looking at the charts, it would seem that the LFB KR-1x2 or S3 KS-25x4 are better engines for my first stage. I'll play around with that on my next launch then.

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...That answer is a lot better then I was expecting!

First things first then; I will stand corrected on your tractor light

I need to make it a habit to stop using KER for dV, as MechJeb lists it on one page (And both of em has features the other doesn't have.....)

Your explanation on what ISP means in plain language clears a lot up

Your post did give me the motivation to work on the efficiency of one of my self designed rockets ... 13.1%!

Taverts are interesting!

* If you bother to ask a proper question you deserve a proper answer :-)

* Bit of a relief that Pecan is only slightly nuts about the tractor design then ^^

* KER is fine - it, MJ and VOID (and probably some I don't know of) are excellent information mods. As it says right there in the introduction (Chapter 1, the OP), "Kerbal Engineer Redux (KER), MechJeb (MJ) and/or VOID – important and sometimes vital information you need for designing vehicles, such as TWR and deltaV stats. There is a lot of overlap in what these can display so you only need one of them, but you may prefer more." Partly it's a process of finding out what you need to know and finding which mod provides it the way you like. Personally I use MJ because of the custom windows and, since I test launches A LOT, I want repeatability, not my own dodgy button-pushing. With these, and the whole of KSP, find the way you feel comfortable with - there are no extra points for doing things the 'hard' way :-0

* ISP is just fuel-efficiency. A 'better' engine might work well in the short term but for long journeys or heavy payloads it comes down to this. Now learn the rocket equation, which is what it's really about! That's simple too, as it happens ... "Ve" = "Isp * 0.92" -> means engine efficiency counts. "M0/M1" = "mass-with-all-the-fuel / mass-once-you've-used-it" -> with more fuel available you go further. "ln(M0/M1)" = natural logarithm of how much fuel is available -> but double the fuel doesn't mean double the difference, because a lot of the fuel is used just to push the rest of the fuel. SO: (efficient engines) * diminishing_returns_of(lots of fuel) -> how much you can change which way, and how fast, you're going = deltaV. [Tsiolkovsky's ideal rocket equation: deltaV = (Isp * 0.92) * ln(M0/M1)] If you haven't seen this before - YES - this is really what it means and the way it's worked out.

* Inspiration is the greatest gift I hope to offer. Merry Christmas! And you've done a lot better than you thought you could; something must be working :-)

* Tavert's charts are a little outdated. John FX is updating them at the moment but I seem to have lost my link to that thread ... (let me know if you have it, please).

I'm not going to comment on your ship unless you specifically ask, you flying dude! It works! It's better than you knew before! It's good! What YOU build YOU can be proud of :-) Also note that I'd been playing KSP for only 4 months when I started writing this tutorial/campaign. You will learn fast and go far - enjoy it :-)

Edited by Pecan
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Here’s John FX’s updated charts; they begin from this post in the thread. (I’m working on a similar script that pulls its info from GamaData/ directly, so it would automatically allow comparison with any mod parts. WIP.)

BTW, a suggestion for a mention in the tutorial  I am a fan of the Improved Chase Camera mod for plane flying. One of those simple ones that could easily just be stock behavior.

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Update for 0.90 will take a while. It's much larger than I expected; mainly due to SAS changes in the game, which means the SCANSat satellites of Chapter 2 have to be re-built, and new spaceplanes. As taio pointed-put the Orbiter SP was seriously out of date (the new 'Orbiter Mk2' is very pretty and flies a lot better). I've only got through Chapters 1 - 4 so far and will publish an interim update once I've done Chapter 5. Sorry for the delay but apart from re-designing and testing the new vehicles I have to fly the missions repeatedly to get screenshots and test how different handling affects performance. Then I need to update the stats and get all the book-keeping straight and then I can re-write the text to reflect the new characteristics of the craft.

In the mean time - anyone starting with this should place an inline reaction wheel on the SCANSat satellites (including Placebo, if you're not using the mod).

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Still working on the 0.90 update. Chapter 2: Trainer Mk1 replaced with a really stable and easy to fly 'plane, Mk1 Rocket replaced with ("Rocket 1A/B") which just has an inline reaction wheel. Chapter 3: Satellites use an OKTO (not OKTO 2) probe-core. Chapter 4: Orbiter SP replaced with Orbiter Mk2 which is not only pretty, as mentioned above, but uses a rapier engine to introduce the concept and provide an intermediate step between jets and rockets, SatStack just changes as the individual satellites do (OKTO 2 -> OKTO). With these done I'm not expecting so many, or such large, changes for the other chapters as it's mainly the SAS that affects these small ones.

Anyway it's christmas. I'm not a christian so it doesn't mean much to me but large meal had to be cooked and much food and drink consumed. One of the other people who lives on this smallholding managed to get a rocket into orbit for the first time and, generally, I'm not exactly on the case 100% ^^.

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For those wanting to get on with this in 0.90 I have posted a link to the new ships for Chapters 2 - 5 in the OP.

There's a lot of stats and text changes to come but the existing instructions should make sense if you squint a bit and ignore the parts-lists ^^. There shouldn't be many significant changes to the heavier vehicles in the second half so I'll focus on updating these first chapters before re-building those ships. Please let me know if you encounter any specific problems.

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I'm loving this work, some solutions you present are really cool (like that for over 2 motors on each OrbiterSP fuel tank). Never I would imagine it. I'm the new version, but do not rush. The important thing is that it enhance everything you've done so far.

Happy Holidays to you and family!

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Hi Pecan - thanks so much for making this tutorial. I've driven the rover and flown the space plane, and I took a break from suborbital launches to launch a Kerbal X because I was having a problem with the baby rockets and wanted to see if I could launch anything.

I'm running into a weird issue with the Stayputnik/fuel tank/engine construction where the engine just stops working after 3000m, even when there's plenty of fuel left. I tried substituting some parts other than the ones you recommended and had the same problem. The engine burns about 10 units of fuel getting to 3000m and then dies.

Also, can you update the link in the introductory post to point to the new collection of builds? I figured it out eventually, but I worry other people might not be as persistent.

- - - Updated - - -

I figured out the 3km problem - I had RemoteTech installed and it was killing my launches when the computer lost connection. I removed it and just put my first rocket into orbit with just SAS assistance :)

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Yeah, RT does that; it's a common thing that takes people by surprise. As it says in the OP "Note that while this is installed you will NOT be able to control unmanned vehicles while they are out of communications."

Re-formatted the links in the OP slightly. All the text in the thread and PDF refer to the existing 'stock ships download' so I don't want to change that link to point at the new ships and have everyone thinking "huh? This ship doesn't look like that!" Hopefully it is clear(er) now that the thread and downloads are for 0.25. The first-half update should be ready to publish by the weekend and, as I've said, the second half should be much easier.

Did you have any problems apart from RemoteTech?

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Did you have any problems apart from RemoteTech?

Of course I'm having problems apart from RemoteTech! :)

I just removed FAR and Procedural Fairings because I'm encountering enormous AoA/sideslip problems with Sidestep and Quickstep that make them essentially un-launchable. I suspect the problem is something else that I can't identify yet, but going back to stock KSP is a start.

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Hehe, I knew there was something I wanted to add to the introduction.

Since "You will need to redesign your craft and re-learn how to fly them in atmospheres with these installed." attached to the FAR/DRE mod does not seem sufficient the next version includes a specific warning that these designs won't work with them!

Procedural Farings is fine though, I use it most of the time. Make sure you put the throttle to full before launch as well, rather than leaving it at the default 50% (apparently Squad believe that's better than newbies not knowing why their engines don't fire).

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The new ones are included in the OP links for the 0.25 stock ships and 0.90-compatible ships. Thank you for pointing-out that the link in the text is obsolete.

I have been a bit ill but the first half of the update will be posted this weekend (including correcting that link in Chapter 2).

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Chapter 6, Project Lacuna, updated.

Completely changed this is now "The Joy Of The Small" and the vehicles in it are, er, small ...

(Ships and pictures download files also updated).

All the links remain in the OP.

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Thank you for continuing the updates.

I'm struggling with 0.90 career running out of money or being pushed to do the same flyover missions, I seem to be stuck in a recursive loop.

Hopefully your "Career - Intermediate; contracts, money, science, reputation, strategies, crew." will solve that.Oh and I am always up for guides using KVV!

"The cantab principle"? Not an Oxon man I trust!

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cantab is a forum member.

I'm MA (Oxon), Phd from OU :-)

My computer can hardly cope any more and it's old, poor thing.

Attention everyone! I live on < £7,000/year, including rent, heating, food, and everything else. I'm not complaining, but I need a new computer and since I'm in the UK I get ripped-off by US and Japanese manufacturers (although NO ONE is as bad as Adobe - they need to learn that "conversion rate" does not mean changing the "$" sign to "£"). One of the ways I'm going to raise the money is by publishing and charging-for KSP guides after this.

Nope, I still really don't know how I'm going to organise them

Edited by Pecan
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Chapter 7 updated at last. Rather than the expected "almost no changes" I re-thought the whole end-tutorial scheme and you're now getting basically the ships I use all the time. The principle is the same but all ships except the tractor are re-designed and the text completely re-written (hopefully correctly). Chapter 8 will also be almost entirely re-written.

Links in the OP, as always.

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