How FAR can you fly on a single BACC booster?

[cakepie]

Here's the challenge: Build a stock-only spaceplane using a single BACC booster as the only source of propulsion, and see how far you can fly it. Take off from the KSC runway, and come to a safe conventional aircraft landing (that means no parachutes!) anywhere on Kerbin of your own choosing.

Rules:

• stock parts only, except Engineer, VOID, or similar information mod for determining coordinates of end location. No autopilots.
• Ferram Aerospace Research and/or Neophyte's Elementary Aerodynamics Replacement are pretty much required to make the challenge aerodynamically interesting.
  • However I will track results for stock aerodynamics separately if people are interested in giving that a shot.
  • Edit: Stock aero attempts seem to be devolving into achieving infliniglide -- this is permitted, since I do not wish to get into the business of judging entries based on whether infiniglide is factor.
    If you don't care for infiniglide, feel free to disregard stock aero section and make your attempt with FAR/NEAR.

  [*] must be a plane, horizontal takeoff and landing; must land safely (i.e. intact). no parachutes!

  • take off from the runway, eastbound, starting from the spawn location.
  • please come to a prompt and safe stop once landed -- rolling on the ground is not "flying" and should not count. (Please be honest.)
  • landing intact in water: allowed -- props to you if you can pull it off.

  [*] propulsion to consist of one (1) BACC solid rocket booster only. you may tweak the thrust limiter. (you probably should.)

  • Nothing else. No liquid fuel, oxidizer, monoprop, xenon, etc. allowed at all. No rover wheels.
  • No driving on the ground allowed please. Only time you should be moving on the ground are takeoff, which must be on the runway, and landing, for which you should minimize the length of the rollout.

  [*] you may not lose or discard any part of the craft on the way -- build a rocket-powered plane, not a rocket-boosted glider. This includes: no leaving parts behind during launch.

  [*] both manned craft and drones are permitted (separate leaderboards will be maintained to account for payload mass difference)

  [*] you may launch at a time of your choosing (due to: affects electrical power considerations for unmanned craft)

Scoring:

• to submit your attempt, state your general direction traveled (N/E/S/W) and lat long coordinates of final landing place, accompanied at minimum by screenshots of :
  • map view at some point approximately mid-flight, showing craft location; including navball, showing flight direction (usually: east)
  • for each time you make a full circle around Kerbin, make a separate screenshot to prove when you pass over KSC.
  • craft intact after safe landing, with coordinates of final landing place.
  • more thorough mission reports are of course welcome.

  [*] please indicate if you are using Stock, Ferram Aerospace Research or Neophyte's Elementary Aerodynamics Replacement aerodynamics.

  [*] results will ranked by distance as determined using great circle distance from the runway starting position at (0.0486°S, 74.7244°W).

  Exact formula will depend on how many half-revolutions traveled, but will be of the form: N x Kerbin circumference +/- GCD

  [*] you may go to space, i.e. suborbital flight, but must eventually land somewhere on Kerbin for your attempt to count.

  • achieved stable orbit? (tbh I'm not completely sure that's even possible) That's nice, now you're stuck without propulsion.
  • if you manage to get into a very slowly decaying orbit, I guess you win an internet.

Tips:

The key to doing well is managing an optimal suborbital ascent, combined with designing a craft with excellent glide characteristics. Unmanned entries will need to consider electrical power management, as well as contend with the lack of torque if you only bring a probe core. Set the thrust limiter wisely -- it's the only throttle control you'll have. Use SAS to hold a long, steady glide.

After a couple of test flights to get a good idea of the range you have, plan ahead and decide on viable landing zones for your actual attempt. You might find Kerbal Maps helpful for this.

But is it even possible?

With FAR installed, and using an unmanned craft built to the above rules, I've just pulled off a circumnavigation of Kerbin, overshot the island runway by a chunk, and then turned around and landed back at KSC with plenty of energy (i.e. altitude) to spare. So yes, you can get surprisingly FAR with just one BACC booster!

   

With stock aerodynamics: basically devolved into a test in infinigliding; see comments about above in "Rules" section.

Just to set reasonable expectations of what's viable with stock aerodynamics: I did a quick and simple attempt and reached a distance of about 100+ km flying NE along the coast.

 

Leaderboard

Manned FAR/NEAR

1. tbd

Manned Stock

1. Monthar (Triple Eastward circumnavigation) 11310km
2. cantab (North to 9.6586°N,74.6574°W) 101.2km

Unmanned FAR/NEAR

1. cake>pie (Eastward circumnavigation) 3770km [FAR]

Unmanned Stock

1. cantab (Northwest to 23.0686°N,94.813°W) 316.3km (mild damage sustained on landing)
2. cake>pie (Northeast to 8.209548°N, 67.897527°W) 111.8km

Edited April 17, 2018 by cakepie
various rule clarifications; comment on infiniglide

[Death Engineering]

Interesting.. is it permissible to drop the BACC after it has been expended?

[cakepie]

Interesting.. is it permissible to drop the BACC after it has been expended?

I intended for rocket-powered planes rather than rocket-boosted gliders (flavor-wise imagine that you could refuel and reuse the craft rather than replace a significant chunk of it) -- so I'd say no to that. Rules clarified.

I've also made it clearer that FAR/NEAR are pretty much needed if you want to pull off anything like a circumnavigation like I did -- you wouldn't get very far on stock aerodynamics only -- although if people want to try that, I can maintain a separate leaderboard for that as well.

[Cmdr. Arn1e]

are we allowed to build a launch rover, drive it up a hill, and launch from there? Only way you could get further in the stock aero model, I think...

[cakepie]

are we allowed to build a launch rover, drive it up a hill, and launch from there? Only way you could get further in the stock aero model, I think...

No, please launch starting from the spaceplane spawn point, and take off from the runway. Everyone needs to start from the same location in order for the results to be meaningfully ranked. After all, this is a challenge about designing and flying a rocket plane, not a challenge about finding a high place to launch from.

Therefore no driving anywhere before launch and after landing (please minimize length of landing roll out).

[cantab]

So no 2869 km high launch towers?

[cakepie]

Nope, no launch towers please. It's all about the aero design of your craft, not just hurling it from as high a starting point as possible.

Edit: also, that would break the rule re: not allowed to lose or discard any part of the craft on the way -- if you build a launch tower, well, that gets discarded and left behind. So that's a no-go.

Edited September 3, 2014 by cake>pie

[Kasuha]

Stock aerodynamics is full of oddities, you can achieve some pretty extreme gliding ratios in it. Here my test design (using no control surfaces, just uncontrollable wings, and no control inputs at all) flew some 2 km in 10 minutes while losing only 11 m in altitude. It's just a guess but it might be able to fly some 4000 km if deployed to 20 km by the SRB and left gliding for about a week but I'm afraid I don't have the patience for that.

[Monthar]

Do the Spaceplane Plus parts count as stock since it is being incorporated in the next build?

Edit: What about using Stock Drag Fix instead of FAR/NEAR?

Edited September 3, 2014 by Monthar

[cantab]

Stock entry here.

Unmanned, flew northwest on a rocket-style profile ie straight up as soon as possible then pitchover at 10 km, landed at 23.07° N, 94.81° W.

On the runway by cantab314, on Flickr

Trajectory by cantab314, on Flickr

(Ooops no navball, but VOID has all the info.)

Don't land in the water! by cantab314, on Flickr

Intact landing by cantab314, on Flickr

Well, mostly intact. If it hadn't sideslipped for no obvious reason (you can see that in the picture before) I might have been alright.

Couple more pics in the mission album: https://flic.kr/s/aHsk2ZwcMB

[cakepie]

I just realized I messed up my math with my stock demo flight. It's actually 111.8km, not 20km >_<

I'll just use Wolfram Alpha from now on rather than try to calculate by hand. XD

Stock aerodynamics is full of oddities, you can achieve some pretty extreme gliding ratios in it. Here my test design (using no control surfaces, just uncontrollable wings, and no control inputs at all) flew some 2 km in 10 minutes while losing only 11 m in altitude. It's just a guess but it might be able to fly some 4000 km if deployed to 20 km by the SRB and left gliding for about a week but I'm afraid I don't have the patience for that.

Thanks for your proof-of-concept input on the viability of stock attempts! I'd have to agree that if you leverage all the weird quirks of stock aero you could most definitely do much better than my demo flight.

You should totally do an actual official attempt -- just put the craft in SAS glide on timewarp, set an alarm with Kerbal alarm clock, and leave it in the background while you work, or something.

Do the Spaceplane Plus parts count as stock since it is being incorporated in the next build?

Edit: What about using Stock Drag Fix instead of FAR/NEAR?

No SP+ please -- it is not stock yet, and there are likely going to be quite some differences from what it is now when it does come out in 0.25. Please work with the stock parts in the game at this time.

Of course, if this is still running when 0.25 comes out, then the new parts would be fair game since everyone will have them.

As for Stock Drag Fix, I have no experience playing with that but I think it would behave sufficiently differently from all of stock, FAR and NEAR that it wouldn't be fair to rank them together.

You're welcome to make an attempt, regardless, and I will track that separately if there is enough interest.

Stock entry here.

Unmanned, flew northwest on a rocket-style profile ie straight up as soon as possible then pitchover at 10 km, landed at 23.07° N, 94.81° W.

...

Well, mostly intact. If it hadn't sideslipped for no obvious reason (you can see that in the picture before) I might have been alright.

Nice! Shame about that slight damage =(

[cantab]

A manned entry along the same lines, but with even less weight of wings - just three small control surfaces - and wider landing gear. Headed north, landed at 10.56° N, 76.10° W.

Ready for takeoff by cantab314, on Flickr

I put it way over the side of the SPH, so it spawned over the bank and rolled back, allowing me to do a ski-jump takeoff. The plane can takeoff normally but I figured this'd let me use a bit more fuel for climbing.

Trajectory by cantab314, on Flickr

Safely landed by cantab314, on Flickr

More pics in the mission album. I filled in some "gaps" in my screenies using a previous run that crash-landed there.

If you disallow the carrier-style takeoff, Jeb's run used a regular takeoff and landed at 9.66° N, 74.66° W, https://flic.kr/p/p4WEDA

Edited September 4, 2014 by cantab

[cakepie]

I put it way over the side of the SPH, so it spawned over the bank and rolled back, allowing me to do a ski-jump takeoff. The plane can takeoff normally but I figured this'd let me use a bit more fuel for climbing.

<snip>

If you disallow the carrier-style takeoff, Jeb's run used a regular takeoff and landed at 9.66° N, 74.66° W, https://flic.kr/p/p4WEDA

That's a cute trick that surprised me a bit, but ultimately to be consistent I'll have to take the result for the regular takeoff run, since I did specify:

take off from the runway, eastbound, starting from the spawn location

[Monthar]

I made a fresh stock install folder and added just engineer redux, enhanced navball, kerbal alarm clock, toolbar (mainly for the alarm clock's button) and active texture management. Then I started a new career and edited the save to have the initial contracts give 100x science and funds just to be sure I could unlock the parts and have the cash to launch my attempt without having to spend days building them up. Before making the fresh install I had already designed and tested a nice looking delta-wing bi-plane, so I copied that aircraft file over to the new install and verified that it was in fact all stock parts.

I launched the plane heading due east, got up to an altitude of about 13km and dropped down to around 9900m before I got the SAS to stably hold my pitch between 15 and 20 degrees. At that stable pitch the aircraft can glide with a vertical speed oscillation between -5m/s and +5m/s and maintain the altitude between 9600m and 9900m pretty much indefinitely. I say pretty much, because every now and then the SAS would glitch and drop the nose which would take until about 6500m altitude to get it stabilized again. However, once stabilized the aircraft would slowly gain altitude until back up to the 9600-9900m range. I think when it would hit 10km altitude is when the SAS would glitch causing the sudden pitch down.

With that stable flight I was able to get up from the computer and watch tv and only have to check on this epic flight every 20-30 minutes. Last night I did this for about 1d 3hrs flight time before I was too tired to stay awake any longer. So I saved and paused the game intending to continue this flight when I woke up. The flight was just about past the big desert, ie. most of the way around on the first circumnavigation.

While I was sleeping we had a thunderstorm blow through which caused the power to go out like usual. I suspect this time it was probably another of those brown-out situations where the power would drop, return and drop again a few times before coming back up to normal levels. So when I woke up, unfortunately my computer wouldn't power up. After determining the power supply was fried and picking up a new one at Best Buy, I then learned that when the power supply blew it took out the cpu, motherboard or both. Since I can't see any scorch marks or obviously blown components, it seems I'll have to replace both the MB and CPU. At this point it might be a few weeks before I can get the parts to finish fixing my computer. That leaves me with just the wife's laptop to check forums and such.

Edited September 5, 2014 by Monthar

[sdj64]

Yes, stock is entirely possible to circumnavigate, I'm sure even without any infinigliding. There was a challenge once to launch a glider off of a rocket sled (so no propulsion at all after you leave the ground) and some attempts made it past 50 km. Can't find the forum entry right now though.

[cantab]

I suspect the biggest advantage of FAR won't be the glide performance - Kasuha and Monthar have shown stock planes can glide well - but the massively lower drag in the ascent. From a pure delta-V perspective a BACC's enough to make orbit in FAR, but about 500 m/s short in stock.

[Kasuha]

Using SAS, you can make the craft infiniglide even if you use just one control surface. When I was doing my experiments I got the plane "infinigliding" even with no control surfaces at all - at maximum pull down when it was upside down, it was flying about 2 m/s and slowly gaining altitude. So I believe the only fair way to make an attempt using stock aerodynamics is to use no control surfaces and no control at all (SAS off).

[Monthar]

Good news for my pc. I found the modular power cables (can plug into any modular power supply) from the old power supply for the DVD and the HDD both had a short. It was possibly just dust in one of the connectors in each cable, but I swapped both out with the new modular cables that came with the new power supply and now my system boots up with no apparent problems. Well one of the three case fans quit working, but that's a much cheaper fix and the system can run just fine without it. So I should be able to submit my attempt soon.

[cakepie]

Glad to hear that your PC isn't as damaged as it initially seemed, Monthar. Will be awaiting your attempt.

As for stock aero quirks, infinigliding, etc -- my policy here I guess is, if you're patient enough to try it and pull it off (without breaking the rules), I'll give you the credit for doing so.

Should be pretty obvious I usually play with FAR rather than stock aero, so I'm not as familiar about the various tricks you can pull there. Heck, I initially planned on a FAR-only challenge, but then decided to make it more inclusive.

I suspect the biggest advantage of FAR won't be the glide performance - Kasuha and Monthar have shown stock planes can glide well - but the massively lower drag in the ascent. From a pure delta-V perspective a BACC's enough to make orbit in FAR, but about 500 m/s short in stock.

That sounds about right to me.

[CDK]

cantab (first post): You got to update to 24.2.

[cantab]

I've got a few big missions still going on .23.5 and don't want to have to troubleshoot compatibility issues. As such I've declined to change versions. So far as I know none of the parts I've used for the flights here changed in .24.

[CDK]

Yeah, I would do that too if I were you.

[Monthar]

After getting my computer up and running again I found some corrupted windows files and had to reinstall the OS. While at it I also moved most of my games to a 2nd HDD. Thus I didn't get around to flying more of this challenge until today. Here's a preview of my upcoming entry. This is my first circumnavigation flyover of the KCS.

Edit: I forgot to mention that prior to launch I removed all the mono-propellant from the command module. Since I wasn't going to be using any I didn't see any need to carry the extra weight.

Edit2: I landed on the KCS runway after the 3rd circumnavigation. I could have kept going, but I wanted to end this attempt.

Rather than filling the post with all the screenshots, here's a link to the slideshow. It is 18 of the 120 normal screenshots, both normal and map views, I took during the mission, including the 2 flyovers of KSC, several of the landing sequence on the 3rd circumnavigation and Jedediah doing an EVA pose after the landing. Total mission time 6 days 2 minutes and 21 seconds.

http://s738.photobucket.com/user/Monthar/slideshow/KSP%20BACC%20Glider%20Challenge

Edited September 11, 2014 by Monthar

[cakepie]

I landed on the KCS runway after the 3rd circumnavigation. I could have kept going, but I wanted to end this attempt.

Nicely done, added =)

[WoofMcMoose]

Stock Aerodynamics. Throttled SRB to 60%, coming in to land after 200 km and pitching up slowly to eek out every last drop of airspeed as lift. And then....

Infinite glide achieved! Though I'm not sure i can wait for a full circumnavigation at 16m/s