DaveyJ576 Posted May 27, 2023 Share Posted May 27, 2023 1 hour ago, Alpha512 said: Am i doing something wrong or is INT-20 (3x F-1A) a ridiculously anemic vehicle? With full S-IC load it can't even lift off, and even with reduced prop load, dry weight is way too high and TWR is way too low. Shortening the S-IC makes it a bit more reasonable, but the overall performance is hardly any better than LRB-260 (2x F-1A) with S-IVB on top, so no extra gain for an extra engine I would say that something is amiss. See my post on page 1187. I routinely fly a three F-1 (not F-1A) INT-20 with an orbital version CSM and a payload in the SLA and the thing leaps off the pad! Full fuel load in both the S-1C and the S-IVB. I use KSRSS at 2.5x scale. It has superior performance all around, easily outclassing the Saturn IB. I am really not sure what is going on in your case. You should be getting great performance. Quote Link to comment Share on other sites More sharing options...
RocketBoy1641 Posted May 27, 2023 Share Posted May 27, 2023 (edited) 1 hour ago, Alpha512 said: Am i doing something wrong or is INT-20 (3x F-1A) a ridiculously anemic vehicle? With full S-IC load it can't even lift off, and even with reduced prop load, dry weight is way too high and TWR is way too low. Shortening the S-IC makes it a bit more reasonable, but the overall performance is hardly any better than LRB-260 (2x F-1A) with S-IVB on top, so no extra gain for an extra engine https://en.m.wikipedia.org/wiki/Saturn_INT-20 Edited May 27, 2023 by RocketBoy1641 Quote Link to comment Share on other sites More sharing options...
Zorg Posted May 27, 2023 Share Posted May 27, 2023 18 hours ago, NiL said: What's the part used for the second stage of this beautiful rocket? One of the Orion 50 models, I forget the designation. The build is also missing the 3rd stage cos I was in a rush but don't tell anyone (that would be a shorter Orion 50). Quote Link to comment Share on other sites More sharing options...
Raptor22 Posted May 27, 2023 Share Posted May 27, 2023 Are we ever going to get the Lunar Motorbike planned for an LRV alterative or in addition to it for Apollo 20? It's just ridiculous enough to fit right at home in KSP, IMO. Quote Link to comment Share on other sites More sharing options...
Pappystein Posted May 27, 2023 Share Posted May 27, 2023 On 5/24/2023 at 6:30 AM, GoldForest said: There was an engine called the J-2X which was proposed for the SLS upper stage, but it's a J-2 in name only apparently. It used no hardware from actual J-2s. J-2X started as as scaled up J-2S... but as we learned with F-1, you can't scale an engine up past a certain point... Then it became a clean sheet design utilizing the "knowledge" gained from the J-2. So at BEST you could call it like a F/A-18E/F/G hornet vs a F/A-18A/B/C/D Completely unrelated but it sorta looks the same and stupidly uses the same designation. (PS, I am a semi OK fan of the Super Hornet... but it should be designated AF-24,-25 or -26 not F/A-18) Quote Link to comment Share on other sites More sharing options...
biohazard15 Posted May 28, 2023 Share Posted May 28, 2023 On 5/27/2023 at 9:30 PM, Raptor22 said: Are we ever going to get the Lunar Motorbike planned for an LRV alterative or in addition to it for Apollo 20? It's just ridiculous enough to fit right at home in KSP, IMO. IIRC there was some discussion about it several years ago. Highly unlikely, since such vehicle would need a ton of hacks and probably a plugin to function. Quote Link to comment Share on other sites More sharing options...
Davi SDF Posted May 28, 2023 Share Posted May 28, 2023 (edited) On 5/27/2023 at 8:28 AM, DaveyJ576 said: I would say that something is amiss. See my post on page 1187. I routinely fly a three F-1 (not F-1A) INT-20 with an orbital version CSM and a payload in the SLA and the thing leaps off the pad! Full fuel load in both the S-1C and the S-IVB. I use KSRSS at 2.5x scale. It has superior performance all around, easily outclassing the Saturn IB. I am really not sure what is going on in your case. You should be getting great performance. Hm... I'm having the same problem though, i have a INT-20 with 3 F-1As and a full S-1C fuel load, and it's TWR at sea level is 0.96 with 35 Tons of payload. I have an exact INT-20 (three F-1) build, am i missing something? Edited May 28, 2023 by Davi SDF Quote Link to comment Share on other sites More sharing options...
DaveyJ576 Posted May 29, 2023 Share Posted May 29, 2023 3 hours ago, Davi SDF said: Hm... I'm having the same problem though, i have a INT-20 with 3 F-1As and a full S-1C fuel load, and it's TWR at sea level is 0.96 with 35 Tons of payload. I have an exact INT-20 (three F-1) build, am i missing something? Without more specifics about your mod list, it will be hard to say. I am a poor one to assess that, but post it and perhaps someone else can find the conflict. All I can say is that my INT-20 flies like a dream. Quote Link to comment Share on other sites More sharing options...
AlphaMensae Posted May 29, 2023 Share Posted May 29, 2023 (edited) On 5/27/2023 at 5:57 PM, Pappystein said: J-2X started as as scaled up J-2S... but as we learned with F-1, you can't scale an engine up past a certain point... Then it became a clean sheet design utilizing the "knowledge" gained from the J-2. So at BEST you could call it like a F/A-18E/F/G hornet vs a F/A-18A/B/C/D Completely unrelated but it sorta looks the same and stupidly uses the same designation. (PS, I am a semi OK fan of the Super Hornet... but it should be designated AF-24,-25 or -26 not F/A-18) The military services have learned that it's a lot easier to get "upgrades" to exisiting weapons systems through Congress than to get a whole new one. Hence the E/F "upgrade" to the Hornet. Same with the Abrams tank and the Patriot SAM (which is an entirely different missile than the Desert Storm version). Edited May 29, 2023 by AlphaMensae Quote Link to comment Share on other sites More sharing options...
Foxxonius Augustus Posted May 29, 2023 Share Posted May 29, 2023 2 hours ago, AlphaMensae said: and the Patriot SAM (which is an entirely different missile than the Desert Storm version). That's not true, it uses exactly the same screws! Well at least the same shape of screw, just a different size and material is all Quote Link to comment Share on other sites More sharing options...
Alpha512 Posted May 29, 2023 Share Posted May 29, 2023 (edited) On 5/27/2023 at 2:28 PM, DaveyJ576 said: I would say that something is amiss. See my post on page 1187. I routinely fly a three F-1 (not F-1A) INT-20 with an orbital version CSM and a payload in the SLA and the thing leaps off the pad! Full fuel load in both the S-1C and the S-IVB. I use KSRSS at 2.5x scale. It has superior performance all around, easily outclassing the Saturn IB. I am really not sure what is going on in your case. You should be getting great performance. Your post was one of the main reasons for my question in fact Finally got some time to check the numbers in-game: INT-20 with 3x F-1A on full load, unmodified tankage S-IC plus 1x J-2S on S-IVB, no P/L, fairing or anything above the IU, gets me a wet mass of 575t. S-IC tankage alone is 486t wet, 54t dry. Vehicle has 10.45 km/s vac dV, 1.19 vac TWR and 1.04 SL TWR. I play stock + Rescale 2.5x, so LKO requires about 5400-5500 m/s vac dV. Delta-V wise, the rocket can almost lift a full (35t + 4.3t dry mass) 3.75m ore tank into LKO, with a vac dV of 5367 m/s, but the TWR is just 1.12 Vac/0.97 SL. This leaves me with a very little practically achievable payload of around 10t. Shortening the S-IC by 3m sheds 80t of prop and 10t of dry mass off it, the whole vehicle now weighs 486t wet (no P/L), has 1.23 SL TWR and becomes dV limited in payload capacity with 1.14 TWR, 5km/s dV with 40t PL and a reasonable but not very exciting LKO capacity of ~29t (1.16 SL TWR, 5567 m/s vac dV). Any help at solving this mystery will be greatly appreciated. Disclaimer: all data is from stock and KER readouts in VAB, no actual test flights were performed. On 5/27/2023 at 3:15 PM, RocketBoy1641 said: https://en.m.wikipedia.org/wiki/Saturn_INT-20 Sorry? I believe I have seen the Wiki page before (wouldn't call it a very reliable source tho). Edited May 29, 2023 by Alpha512 typossss Quote Link to comment Share on other sites More sharing options...
OrbitalManeuvers Posted May 29, 2023 Share Posted May 29, 2023 1 hour ago, Alpha512 said: INT-20 with 3x F-1A on full load, unmodified tankage S-IC plus 1x J-2S on S-IVB, no P/L, fairing or anything above the IU, gets me a wet mass of 575t. S-IC tankage alone is 486t wet, 54t dry. Vehicle has 10.45 km/s vac dV, 1.19 vac TWR and 1.04 SL TWR. This build yields the same numbers for me. Quote Link to comment Share on other sites More sharing options...
Queen Ultima Posted May 30, 2023 Share Posted May 30, 2023 (edited) 1 hour ago, Alpha512 said: Disclaimer: all data is from stock and KER readouts in VAB, no actual test flights were performed. I was quickly toying around with it at JNSQ scale (specifically this craft file, forgive the quick upload I don't have time to go back in for screenshots after a crash) and I've found that the TWR rapidly increases as the first stage progresses. At launch I had about 1.04 (IIRC) TWR, while at T+ 01:30 at 6000m above sea level I had 1.60 TWR (roughly halfway through the first stage). I haven't reached orbit with it (again, it was just a quick build and test) but the ratios just go crazy. It might actually be worth adding a way to drop the other two F1s (like the Saturn V-B) at higher atlitudes. IIRC the real Saturn V had a low TWR at liftoff too. I vaguely remember one of the Apollo 11 crew saying that the lack of Gs from the low TWR was actually unnerving. I'm no expert but it feels like a fatal flaw in the "Saturn III" design, too weak at liftoff and too strong at max Q. Edited May 30, 2023 by Queen Ultima Quote Link to comment Share on other sites More sharing options...
Pappystein Posted May 30, 2023 Share Posted May 30, 2023 38 minutes ago, Queen Ultima said: I was quickly toying around with it at JNSQ scale (specifically this craft file, forgive the quick upload I don't have time to go back in for screenshots after a crash) and I've found that the TWR rapidly increases as the first stage progresses. At launch I had about 1.04 (IIRC) TWR, while at T+ 01:30 at 6000m above sea level I had 1.60 TWR (roughly halfway through the first stage). I haven't reached orbit with it (again, it was just a quick build and test) but the ratios just go crazy. It might actually be worth adding a way to drop the other two F1s (like the Saturn V-B) at higher atlitudes. IIRC the real Saturn V had a low TWR at liftoff too. I vaguely remember one of the Apollo 11 crew saying that the lack of Gs from the low TWR was actually unnerving. I'm no expert but it feels like a fatal flaw in the "Saturn III" design, too weak at liftoff and too strong at max Q. That is the whole reason a lot of people speculated the Saturn II would be the champ. The INT17 is a world-winnner with the S-II skirt being a minimal modification to the Saturn V inter-stage. This easily allowed UA-120x series SRMs to be attached in 2x, 4x or 5x (5x is actually the least amount of modifications!) to the Saturn S-II-360 stage. Initial TWR is around 1.15-1.25 Final S-II burnout is at ~3.0->3.5G payload specific which is considered "safe" for most all payloads. A 3 Engine INT-20 "Saturn III" *I don't know that I have ever seen it called that except in fiction/flavor text on this channel* Has a Low inital TWR that quickly approaches 4.5+Gs which is considered UNSAFE for most space payloads. (the cutoff for safe/unsafe is 3.5G as I recall) This is the real reason that INT-20 was less likely than INT-17. The INT-20 S-IC(or whatever it would be called) was a major re-design of the Saturn V S-IC... where as the MS-II-360 was just a structurally redesigned S-II, which the design work had already been done and mostly certified for the second batch of Saturn Vs (Apollo20? and beyond I think) 23 hours ago, AlphaMensae said: The military services have learned that it's a lot easier to get "upgrades" to exisiting weapons systems through Congress than to get a whole new one. Hence the E/F "upgrade" to the Hornet. Same with the Abrams tank and the Patriot SAM (which is an entirely different missile than the Desert Storm version). You are 100% right. In fact the US Navy and the US Air Force (the people in charge of designating anything that flies through the air) came to blows in public over the Super Hornet. Office of the President(I think, going from memory it could have been SecDef) had to ORDER the USAF to shut up about the Super Hornet.... And now the "F-21" is being floated for new F-16 Designation... F-21 is the IAI Kfir C2 that was flown as an aggressor fighter for the US Navy in the 1980s. Quote Link to comment Share on other sites More sharing options...
Alpha512 Posted May 30, 2023 Share Posted May 30, 2023 (edited) 13 hours ago, Pappystein said: That is the whole reason a lot of people speculated the Saturn II would be the champ. The INT17 is a world-winnner with the S-II skirt being a minimal modification to the Saturn V inter-stage. This easily allowed UA-120x series SRMs to be attached in 2x, 4x or 5x (5x is actually the least amount of modifications!) to the Saturn S-II-360 stage. But its uglyyyyy (Actually, i think it has its charm, and i find it kinda interesting from engineering & performance standpoints, but pure aesthetics - u g l y) 13 hours ago, Pappystein said: Initial TWR is around 1.15-1.25 Final S-II burnout is at ~3.0->3.5G payload specific which is considered "safe" for most all payloads. A 3 Engine INT-20 "Saturn III" *I don't know that I have ever seen it called that except in fiction/flavor text on this channel* Has a Low inital TWR that quickly approaches 4.5+Gs which is considered UNSAFE for most space payloads. (the cutoff for safe/unsafe is 3.5G as I recall) Is this even with center engine cutoff? Maybe F-1A's throttling capability will help? On 5/29/2023 at 3:46 AM, DaveyJ576 said: Without more specifics about your mod list, it will be hard to say. I am a poor one to assess that, but post it and perhaps someone else can find the conflict. All I can say is that my INT-20 flies like a dream. Would you mind sharing performance numbers for your build? Especially the masses i guess Gotta admit i kinda like the INT-20(-3 in particular) aesthetically and really want to put it to good use in my AU Edited May 30, 2023 by Alpha512 Quote Link to comment Share on other sites More sharing options...
DaveyJ576 Posted May 30, 2023 Share Posted May 30, 2023 @Alpha512, @OrbitalManeuvers, @Queen UltimaBelow are some screenshots from my INT-20 build. I will amend an item that I mentioned previously... the S-IC is only partially filled. Sorry for the mis-statement. Also, I mentioned previously that it "leaped off the pad". Admittedly, that was a bit of enthusiastic hyperbole, as it does rise rather slowly at first. But to my eyes the rate of rise is actually fairly realistic, close to what I remember the Saturn V having for the lunar missions. To be clear, I am using standard F-1s, but with a J-2S on the S-IVB. All tanks are standard length. The payload for these screenshots is exactly what I had for the original post on page 1187, Orbital SM, Block III CM, Tweakscaled Gigantor array in the SIM Bay, four astros, plus LM Lab. By chance, are you guys using any mod that adds consumables or food? I have heard that those mods tend to add a lot of weight to the command pod. I hope this helps. Quote Link to comment Share on other sites More sharing options...
Queen Ultima Posted May 30, 2023 Share Posted May 30, 2023 (edited) 48 minutes ago, DaveyJ576 said: By chance, are you guys using any mod that adds consumables or food? Putting down my mods for clarity (I don't have any LS mods installed) but for the record I'm not having any trouble with the rocket (it's a fun new project). I even managed to make a Munar Flyby with a Saturn V-B variant of the INT-20 (probably could've gone into Munar Orbit but was using the ASTP profile for the CSM and didn't have enough Delta-V to return); with an LEM Lab/Apollo Telescope module. Quote "Saturn III" *I don't know that I have ever seen it called that except in fiction/flavor text on this channel* It's useful though! The "official" names like INT-20 and Saturn V-B and M-S-II-2 (I know that's just a tank but still) are confusing (at least to me) while Saturn III makes immediate sense. It's a Saturn rocket but with 3 big engines. 4 hours ago, Alpha512 said: But its uglyyyyy All. Rockets. Are. Beautiful. (Except OTRAG, there is no beauty in an office block) Spoiler Edited May 30, 2023 by Queen Ultima Quote Link to comment Share on other sites More sharing options...
OrbitalManeuvers Posted May 30, 2023 Share Posted May 30, 2023 1 hour ago, DaveyJ576 said: By chance, are you guys using any mod that adds consumables or food? I have heard that those mods tend to add a lot of weight to the command pod. The craft that I built was the exact craft spelled out in the message, which had nothing above the S-IVB IU. So no life support resources. Quote Link to comment Share on other sites More sharing options...
Raptor22 Posted May 30, 2023 Share Posted May 30, 2023 On 5/28/2023 at 2:19 PM, biohazard15 said: IIRC there was some discussion about it several years ago. Highly unlikely, since such vehicle would need a ton of hacks and probably a plugin to function. I mean, I've seen people be able to get motorcycles to work using stock parts, reaction wheels, etc. I don't think it's too out of the question. If push comes to shove, the bike could be equipped with invisible "training wheels" that collide with the surface if it leans too far to one side or the other in order to prevent it from toppling over. Quote Link to comment Share on other sites More sharing options...
ballisticfox0 Posted May 30, 2023 Share Posted May 30, 2023 3 minutes ago, Raptor22 said: I mean, I've seen people be able to get motorcycles to work using stock parts, reaction wheels, etc. I don't think it's too out of the question. If push comes to shove, the bike could be equipped with invisible "training wheels" that collide with the surface if it leans too far to one side or the other in order to prevent it from toppling over. It really comes down to if you want it to function like a rover that looks like a motorcycle or a motorcycle. Quote Link to comment Share on other sites More sharing options...
OrbitalManeuvers Posted May 30, 2023 Share Posted May 30, 2023 2 hours ago, DaveyJ576 said: Below are some screenshots from my INT-20 build. Are these taken on up to date Reborn and KSC Switcher? I think that black terrain is a bug in the KSC Switcher configs and it irked me enough to ditch KSC Switcher and settle on doing everything from the Cape (katniss). I miss Kourou. Quote Link to comment Share on other sites More sharing options...
RocketBoy1641 Posted May 30, 2023 Share Posted May 30, 2023 19 hours ago, Alpha512 said: Sorry? I believe I have seen the Wiki page before (wouldn't call it a very reliable source tho). I don't consider it Gospel; but it does at least provide some info where other sources... more reputable ones... may be harder to locate. Quote Link to comment Share on other sites More sharing options...
exospaceman Posted May 30, 2023 Share Posted May 30, 2023 Hi how can I get the USA and other decals for BDB? Quote Link to comment Share on other sites More sharing options...
Alpha512 Posted May 30, 2023 Share Posted May 30, 2023 4 hours ago, DaveyJ576 said: @Alpha512, @OrbitalManeuvers, @Queen UltimaBelow are some screenshots from my INT-20 build. I will amend an item that I mentioned previously... the S-IC is only partially filled. Sorry for the mis-statement. Also, I mentioned previously that it "leaped off the pad". Admittedly, that was a bit of enthusiastic hyperbole, as it does rise rather slowly at first. But to my eyes the rate of rise is actually fairly realistic, close to what I remember the Saturn V having for the lunar missions. To be clear, I am using standard F-1s, but with a J-2S on the S-IVB. All tanks are standard length. The payload for these screenshots is exactly what I had for the original post on page 1187, Orbital SM, Block III CM, Tweakscaled Gigantor array in the SIM Bay, four astros, plus LM Lab. By chance, are you guys using any mod that adds consumables or food? I have heard that those mods tend to add a lot of weight to the command pod. I hope this helps. Thanks, this explains everything. This option worked for me too, tho i wanted MOAR As the LUT requires modification anyways, why not shorten the S-IC by 3m? That would be about the same prop mass as 80% fueled full length stage but saving 10t on tank dry weight, and almost no additional R&D expenses Quote Link to comment Share on other sites More sharing options...
RocketBoy1641 Posted May 30, 2023 Share Posted May 30, 2023 (edited) Has there been any consideration of Pioneer Venus multiprobe (1978)? Would a Nerva powered wetlab be something we could get (LH2 only tank)? Thinking of this for a Venus/Mars flyby. Asked and answered on the wetlab. Had been too long since I looked at it in detail. I see it has the full range of B9 fuel switches. But the real question becomes, what color do Kerbals glow? Edited May 31, 2023 by RocketBoy1641 Don't ask. Strange things happen.... Quote Link to comment Share on other sites More sharing options...
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