DAL59 Posted November 9, 2017 Author Share Posted November 9, 2017 (edited) Maybe all ion transfers and separatitrons to cushion the landing? [snip] Edited November 9, 2017 by Vanamonde Quote Link to comment Share on other sites More sharing options...
Superfluous J Posted November 9, 2017 Share Posted November 9, 2017 (edited) While a picture is worth a thousand words, I do not believe the opposite to be true in this case. (I "spoiler"ed the quote so it wouldn't take up even more space [snip] Edited November 9, 2017 by Vanamonde Quote Link to comment Share on other sites More sharing options...
Ultimate Steve Posted November 9, 2017 Share Posted November 9, 2017 What... What happened there... The image is a thousand words... Quote Link to comment Share on other sites More sharing options...
DAL59 Posted November 9, 2017 Author Share Posted November 9, 2017 (edited) oops... On 11/9/2017 at 1:26 AM, sdj64 said: it is mathematically impossible Expand Edited November 9, 2017 by DAL59 Quote Link to comment Share on other sites More sharing options...
KerBlitz Kerman Posted November 9, 2017 Share Posted November 9, 2017 On 11/9/2017 at 1:26 AM, sdj64 said: mathematically impossible Expand Lies! It is physically impossible but Krakenistically possible! Quote Link to comment Share on other sites More sharing options...
DAL59 Posted November 9, 2017 Author Share Posted November 9, 2017 I still think it is possible. With ion drive, jool aerobraking, and slingshots. Quote Link to comment Share on other sites More sharing options...
Cunjo Carl Posted November 9, 2017 Share Posted November 9, 2017 (edited) On 11/8/2017 at 11:10 PM, AeroGav said: I've tried numerous times to create an Enterprise and you go do it by accident when chasing a challenge ! Expand Funnily I was trying to avoid the enterprise look, but kept needing more wings! Hopefully with the chained grandparent strut trick, you'll have the aesthetic (and extra fuel) as well. On 11/8/2017 at 11:10 PM, AeroGav said: I've tried numerous times to create an Enterprise and you go do it by accident when chasing a challenge ! I'm really skeptical this challenge can be done. A vessel's mass divides into fuel, engine and payload. Engine % can't be reduced too far because of the TWR requirement for Tylo, so to get a higher fuel fraction you can go bigger in order to make the payload (probe core, KErbal in a command chair) a smaller % of the total. But you're close to maxing that out on a 50 ton vessel, a 5000 ton monster won't do that much better. Expand Good estimate, and I absolutely agree. There's no more deltaV to be gained by scaling at this point, unless I really need 1.5 of some engine. It was originally a 16ton SSTO for a low weight challenge, and bringing it to its natural weight of ~50 tons bought a few hundred m/s. I wish mk2, mk3 had lower drag On 11/8/2017 at 11:10 PM, AeroGav said: I won't enter this challenge because I can't gravity assist my way out of a paper bag. Expand Right there with ya! On 11/8/2017 at 11:10 PM, AeroGav said: Heavy jet engines outlive their usefulness... Expand Boy howdy do they. I've been dreaming ever more imaginative (read insane) ways to lower drag to ditch one of the two rapiers. So far, I'm stuck with two. On 11/9/2017 at 1:17 AM, JacobJHC said: I had something earlier that was just shy of being able to land. Will try again. Expand Ooh, looking forward to seeing it! We should definately compare notes on this one, and I'm happy to send along my work at any point you'd find it usefull. On 11/9/2017 at 1:26 AM, sdj64 said: So then I turned to excel, because while it only takes one success to prove something possible, only math can prove something impossible. I'm not 100% sure on the assumptions I made, but I believe it is mathematically impossible to do a stock Tylo surface SSTO. The spreadsheet works from bottom to top, using the rocket equation to find the wet mass after each step of the mission and finally telling you what mass you have to devote to your fuel tanks and what you have left over for stuff like wings, cockpit, and engines. Expand +1 for mathing a thing. There's a bunch of little improvements we can make on top of what's expected, and the hope is to solve this problem via death by a thousand cuts. For example, using BigS strakes lets you get wings and fuel in one part, and mk0 liquid fuel tanks have lower dry mass than expected. Having a sheet like this is a great starting point for figuring out which aspects need the most improvement. I happen to agree, by the way, that it won't be possible (atleast on airbreathers+LOx+nukes, I haven't run the numbers on airbreathers+LOx+nukes+ions yet). I'm gonna try anyway though Edited November 9, 2017 by Cunjo Carl Quote Link to comment Share on other sites More sharing options...
DAL59 Posted November 9, 2017 Author Share Posted November 9, 2017 How about no nukes? Make a really long plane with lots of xenon and an ion engine, and some separatrons for the tylo landing. The add wings with 2 vasmirs. The ions will certainly provide enough delta vee for the transfer(no need for slingshots even), though I'm not sure how the take off or lading on kerbin would go. Quote Link to comment Share on other sites More sharing options...
JacobJHC Posted November 9, 2017 Share Posted November 9, 2017 I got a trick or two up my sleeve. Progress continues... Quote Link to comment Share on other sites More sharing options...
Cunjo Carl Posted November 9, 2017 Share Posted November 9, 2017 On 11/9/2017 at 1:49 AM, KerBlitz Kerman said: Lies! It is physically impossible but Krakenistically possible! Expand Hah! I have a couple kraken wheel drives in my back pocket, but I'm hoping not to bring out the dreaded beasts. On 11/9/2017 at 1:50 AM, DAL59 said: I still think it is possible. With ion drive, jool aerobraking, and slingshots. Expand Pace is brisk. Either something cool will happen, or it'll all explode magnificently. Win/win! Ion drive will probably make it possible, but still holding out. One unseen disadvantage of ions is their accoutrements drag hard in atmo. I bet it'd work though. On 11/9/2017 at 1:56 AM, DAL59 said: ... though I'm not sure how the take off or lading on kerbin would go. Expand I'm bringing 'chutes Quote Link to comment Share on other sites More sharing options...
JacobJHC Posted November 9, 2017 Share Posted November 9, 2017 On 11/9/2017 at 2:08 AM, Cunjo Carl said: I have a couple kraken wheel drives in my back pocket Expand Could I borrow one? Quote Link to comment Share on other sites More sharing options...
DAL59 Posted November 9, 2017 Author Share Posted November 9, 2017 If you have trouble with slingshots, you could ask @Matt Lowneor @illectro(Scott Manely)... On 11/9/2017 at 2:08 AM, Cunjo Carl said: Either something cool will happen, or it'll all explode magnificently. Win/win! Expand KSP in a nutshell. Quote Link to comment Share on other sites More sharing options...
Cunjo Carl Posted November 9, 2017 Share Posted November 9, 2017 On 11/9/2017 at 2:10 AM, JacobJHC said: Could I borrow one? Expand Reveal hidden contents Shhh.... Here's some of the good stuff. @EladDv's Kraken Drive 8-0 Quote Link to comment Share on other sites More sharing options...
Ultimate Steve Posted November 9, 2017 Share Posted November 9, 2017 My problem with K-drives in 1.3 is that I can't seem to get them to restart reliably. After a while, the legs break for some reason and they won't interact with the pusher. Quote Link to comment Share on other sites More sharing options...
Cunjo Carl Posted November 9, 2017 Share Posted November 9, 2017 On 11/9/2017 at 2:22 AM, Ultimate Steve said: My problem with K-drives in 1.3 is that I can't seem to get them to restart reliably. After a while, the legs break for some reason and they won't interact with the pusher. Expand That's good to know, besides my ladder drives I haven't tried any since 1.2. Was it just me or did craft get wobblier in 1.3 also? Quote Link to comment Share on other sites More sharing options...
Gordon Fecyk Posted November 9, 2017 Share Posted November 9, 2017 (edited) On 11/9/2017 at 1:51 AM, Cunjo Carl said: I wish mk2, mk3 had lower drag Expand Too bad no mods allowed, or use Ferram Aerospace for drag help. Edited November 9, 2017 by Gordon Fecyk Quote Link to comment Share on other sites More sharing options...
AeroGav Posted November 9, 2017 Share Posted November 9, 2017 On 11/9/2017 at 1:51 AM, Cunjo Carl said: Boy howdy do they. I've been dreaming ever more imaginative (read insane) ways to lower drag to ditch one of the two rapiers. So far, I'm stuck with two Expand Have you considered going with one panther and one rapier instead of two rapier? That combo is 3.2 tons instead of 4 tons. Slightly more thrust at mach 0.8, helping you get a larger craft supersonic, and once the panther gives up at mach 2.8, the rapier is now enjoying a 5x ramjet thrust multiplier. Thrust falls off fast enough after mach 4.5 that airbreathing top speed one vs two rapier isn't much different. Quote Link to comment Share on other sites More sharing options...
qzgy Posted November 9, 2017 Share Posted November 9, 2017 On 11/9/2017 at 2:19 AM, Cunjo Carl said: Reveal hidden contents Shhh.... Here's some of the good stuff. @EladDv's Kraken Drive 8-0 Expand Reveal hidden contents *in hushed tone* i want in.... but that link is broken... Quote Link to comment Share on other sites More sharing options...
Gordon Fecyk Posted November 9, 2017 Share Posted November 9, 2017 You'd have to forbid kOS too, or this could be used. Reveal hidden contents Quote Link to comment Share on other sites More sharing options...
Cunjo Carl Posted November 9, 2017 Share Posted November 9, 2017 (edited) On 11/9/2017 at 5:41 AM, qzgy said: Reveal hidden contents *in hushed tone* i want in.... but that link is broken... Expand *Cough Cough* Reveal hidden contents Whoops. Not sure how that hapenned. Link Krakens must have eaten it. Lets go with that! Anyways, while poking about, I found @EladDv's original postings on it as well over in the spacecraft exchange: K-Drive 122 In other news, I tried making a mk2 version of the enterprise, and big surprise the mk2 fuselage pieces dragged so hard it couldn't leave Kerbin. I wish I took a picture of those insidious 100m long red arrows dragging me back! After reviewing the numbers, I'm going to put more work into lowering the drag (and thus airbreather drymass) on a nuke SSTO before making the probably inevitable switch to ion. Edited November 9, 2017 by Cunjo Carl Quote Link to comment Share on other sites More sharing options...
Zhetaan Posted November 9, 2017 Share Posted November 9, 2017 The best LFO vacuum engine is the Poodle with its Isp of 350. However, working back through the rocket equation, when we take the tank mass ratio of 9 and that engine, the theoretical maximum delta-V for the best hypothetical rocket is about 7550 m/s. Leaving Kerbin orbit from LKO (using the common dV map, so the values may be a bit generous) takes 950 m/s, Tylo orbit takes 1100 m/s, and Tylo landing takes 2270 m/s. I chose these specific values because these are the critical values for which no gravity assist is possible (or practicable; a Mun assist from Kerbin orbit doesn't shave enough dV): you have to burn. Since you also have to return from Tylo's surface and leave Tylo's orbit on engine power (you can aerobrake at Kerbin), those latter two values must be doubled, so the combined total is 950 + 1100 + 1100 + 2270 + 2270 = 7690 m/s. Therefore, this mission requires a nuke or an ion engine (or multiple stages, obviously, but that's disallowed). Leaving Kerbin and making Tylo orbit can easily be done with a nuke, but landing/take-off is another matter. However, that is not necessarily impossible: has anyone considered a direct horizontal burn on a particularly flat part of Tylo's surface using aircraft wheels? I'm not certain of how amenable Tylo's surface is to roving, but is it possible to get a good horizontal run before taking off and making orbit? Quote Link to comment Share on other sites More sharing options...
JacobJHC Posted November 9, 2017 Share Posted November 9, 2017 (edited) On 11/9/2017 at 5:03 PM, Zhetaan said: The best LFO vacuum engine is the Poodle with its Isp of 350. However, working back through the rocket equation, when we take the tank mass ratio of 9 and that engine, the theoretical maximum delta-V for the best hypothetical rocket is about 7550 m/s. Leaving Kerbin orbit from LKO (using the common dV map, so the values may be a bit generous) takes 950 m/s, Tylo orbit takes 1100 m/s, and Tylo landing takes 2270 m/s. I chose these specific values because these are the critical values for which no gravity assist is possible (or practicable; a Mun assist from Kerbin orbit doesn't shave enough dV): you have to burn. Since you also have to return from Tylo's surface and leave Tylo's orbit on engine power (you can aerobrake at Kerbin), those latter two values must be doubled, so the combined total is 950 + 1100 + 1100 + 2270 + 2270 = 7690 m/s. Therefore, this mission requires a nuke or an ion engine (or multiple stages, obviously, but that's disallowed). Leaving Kerbin and making Tylo orbit can easily be done with a nuke, but landing/take-off is another matter. However, that is not necessarily impossible: has anyone considered a direct horizontal burn on a particularly flat part of Tylo's surface using aircraft wheels? I'm not certain of how amenable Tylo's surface is to roving, but is it possible to get a good horizontal run before taking off and making orbit? Expand I'm pretty sure anything over 300 m/s would get too bouncy to control, Tylo isn't the flattest place. It could potentially be done though. Edited November 9, 2017 by JacobJHC Quote Link to comment Share on other sites More sharing options...
Vanamonde Posted November 9, 2017 Share Posted November 9, 2017 If a post is a problem, please just report it, okay guys? Quoting it REPEATS the problem and commenting on it adds to forum clutter for others to click past to get to the actual content of the thread. That being said, we had to remove your pic link, @DAL59. Sorry, but it was causing page loading problems. Quote Link to comment Share on other sites More sharing options...
DAL59 Posted November 9, 2017 Author Share Posted November 9, 2017 On 11/9/2017 at 7:43 PM, Vanamonde said: If a post is a problem, please just report it, okay guys? Quoting it REPEATS the problem and commenting on it adds to forum clutter for others to click past to get to the actual content of the thread. That being said, we had to remove your pic link, @DAL59. Sorry, but it was causing page loading problems. Expand Thank you, @Vanamonde. It was really lagging out my computer too! What's worse is, the link was broken! Quote Link to comment Share on other sites More sharing options...
sdj64 Posted November 10, 2017 Share Posted November 10, 2017 On 11/9/2017 at 1:49 AM, KerBlitz Kerman said: Lies! It is physically impossible but Krakenistically possible! Expand So, I did see one error in my calculation: When I assumed the SSTO payload fraction of 35%, it didn't include any engines or wings used for Kerbin ascent (because the payload fraction challenge specified an inert payload). My test craft had a mass of about 45 tons full and 30 in orbit, for 66%, which puts chemical engines back in the realm of possibility for the Tylo landing and ascent. You can also use your efficient (ion or nuclear) engine in conjunction with your more powerful engines for Tylo, which could maybe save you some more. On 11/9/2017 at 5:03 PM, Zhetaan said: The best LFO vacuum engine is the Poodle with its Isp of 350. However, working back through the rocket equation, when we take the tank mass ratio of 9 and that engine, the theoretical maximum delta-V for the best hypothetical rocket is about 7550 m/s. Leaving Kerbin orbit from LKO (using the common dV map, so the values may be a bit generous) takes 950 m/s, Tylo orbit takes 1100 m/s, and Tylo landing takes 2270 m/s. I chose these specific values because these are the critical values for which no gravity assist is possible (or practicable; a Mun assist from Kerbin orbit doesn't shave enough dV): you have to burn. Since you also have to return from Tylo's surface and leave Tylo's orbit on engine power (you can aerobrake at Kerbin), those latter two values must be doubled, so the combined total is 950 + 1100 + 1100 + 2270 + 2270 = 7690 m/s. Therefore, this mission requires a nuke or an ion engine (or multiple stages, obviously, but that's disallowed). Leaving Kerbin and making Tylo orbit can easily be done with a nuke, but landing/take-off is another matter. However, that is not necessarily impossible: has anyone considered a direct horizontal burn on a particularly flat part of Tylo's surface using aircraft wheels? I'm not certain of how amenable Tylo's surface is to roving, but is it possible to get a good horizontal run before taking off and making orbit? Expand Good analysis, it's nice to see similar delta V figures. You might be able to save 200m/s by landing at speed and braking, and your first 200 m/s could use your most efficient engine to build up speed across the ground? I tried incorporating these changes into a craft, but I'm still coming up short. It has about 1000 m/s too low delta V on the "high thrust" part, and its TWR is only 0.5 where it needs to be 0.8 at Tylo landing. It also is missing electrical systems to run the ions and was tested with infinite electricity on. My spreadsheet says I can devote 5 tons to non-tank stuff, and I'm sitting around 6.5. How to increase the thrust and decrease the engine mass? I think it might be better to just use the rapiers on closed cycle - the engine mass savings might make up for the lower efficiency. If I use those, my non-tank budget drops to 4 tons, but I also lose 1 ton of Terriers, so it's an even trade and I get higher thrust for the Tylo landing. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.