Rakaydos

If I were to figure out how to edit the part files, what would be a good TWR for a 600 ISP engine?

Feel free to prove my assertation that a high absolute thrust engine is needed for that challange, by building an apollo style launcher (asparagus staging is specifically banned) with the delta V for a moho orbit and return carrying a lander WITHOUT using the SLS parts at all. But the point I brought up with that anecdote, is that the imbalance in stock is affecting the challange community, and thus affecting the fun people can have with the game, even though the pre-arm parts are all still there.

Because it's a question of Absolute Thrust, not ISP or TWR. I've already got a "nerfed" launcher that goes apollo style to Dres, that uses three stages of balanced 3m engines (two of which are clusters), and trying to build the same thing with 2m parts would almost certiantly require asparagus staging to he point of being wider than the VAB.

Noone is saying to nerf their Absolute Thrust. Weight (and thus TWR) and ISP are the stickingpoints here.

Because it is a challange that would be effectively impossible in stock if I ignored the OP parts, like so many of you suggest.

I was recently barred from participating in a "apollo to moho" challange because I was using a rebalanced engine mod- the challange creator wanted it stock only.

The ion buff was a good thing for balanced engines, as much as the SLS engines were bad. Now Ion engines are directly comparable to NERVAs for deep space maneuvering- the Ion having a better ISP and more convient form factor, but the NERVA having a higher absolute thrust and TWR. If a third high efficency engine was released, somewhere in the 600 ISP range, we could have balanced engines covering the complete range, from high efficency ions to high TWR solid boosters, staggered between probe, lander, and launcher thrust requirements.

I hate it when people talk about an engine's power like there is only one axis. Theres three, and potentially four once we get money. Absolute Thrust decides how much stuff an engine can lift Thrust to Weight Ratio deturmines how fast it can be lifted ISP shows how efficently it burns fuel. And with budgets, it is my belief that Cost should be an approximation of overall effectiveness, within a fairly narrow range. (IE: A Skipper costs less than 4 LV45s and a cluster adapter) The Absolute thrust of the SLS engines is fine. In fact it's a bit low. But the TWR and ISP are ridculus. Bringing the rockets in line with other engines isnt going to mean they are lifting any less, it just means you actually need to hit the spacebar a few times.

http://1d4chan.org/wiki/Oberoni_Fallacy

I wouldnt step on the nerva's toes quite like that. One of the reasons I suggest the Lv1 and LV1R for the slot is because they're TINY, but have radial mounting so you can scale them up by spamming them. So the ion engines are the most efficent space engine, but have the lowest TWR, and have power management concerns. The NERVA has good thrust and the second highest ISP, but is bulky for its thrust and can be difficult to build around. This "Vasmir Ant" would have a high ISP, and it's tiny thrust is matched to its tiny size, so you could put a dozen around even a 1m tank to get whatever thrust you need without fiddling with cubic struts... but with a poor TWR, the more you add the less delta V you get. Then you'd have the Poodle and 909, and then the rest of the engines.

In the mod I favor, the poodle has been buffed to have an ISP of 410 in vaccum. The mainsail also got shifted to being a high thrust upper stage, between the Skipper and it's old stats, to make room for the LFB using it's old stats. I think there needs to be a low thrust, 600 ISP engine to fit between the lander engines like the poodle and 909, and the NERVA and Ion. The ant engine would be a good canidate IMO, but others disagree.

Keep in mind that thrust isnt the only balancing factor you can play with. Keeping the poodle's thrust (and, compared to the size 2 engines, thrust by cross section) low, you can play with weight to affect its TWR, and it's ISP for fuel efficency. Really, Thrust and Thrust by cross section are the same value, when compared to same size engines. Cross section only matters when you start comparing clusters to single larger engines, with the cluster being less part efficent (but should probably be slightly more effective to make up for it, and more expensive in carear) Also... I put together this rocket in Stock Rebalance mod, but you could probably build one similar-starting with the smallest engine and just enough fuel to give it a 1.4 to 1.5 TWR overall, put it on top of the next smallest engine that ccan still get that TWR, then the next, and so on. (with the rework, adapters have fuel, so thaat's not just aerodynamics) Pay attention to the size of each stage- the lv909, for instance, has only an adapter fueling it, but the RM48-7s has a stack of Oscar Bs taller than an orange tank. (and making flying this thing damn near impossible) I thought this was interesting.

Like the Lv30 vs Lv45? both engines have their uses...

There was a comment in the Suggestions forum that said a new NASA engine (a 1m stock shuttle engine was being discussed) would have to be approved by NASA before it could be added. What if it's not SQUAD that's made the engines unbalanced, but NASA?

http://1d4chan.org/wiki/Oberoni_Fallacy

And if they were balanced, you woundnt have to use them either.

Any comment on having a low thrust high efficency Radial in the LV 1R? Having something sitting on the 600 ISP range that's easier to fit than the 800 ISP LV-N and doesnt have the powermanagement issues of the Ion would give a smooth transition all the way up and down the curve.

I would like to see the Ant engine be given a space ISP of 600, with TWR changed to match the curve. This fits it between the LVN and the revised Poodle, while it's anemic thrust remains the same. Not as efficent as an Ion engine, but without the power requirements.

It's a matter of getting the full experience. If I dont want to deal with precision maneuvering, I can install Mechjeb. If you dont want to deal with designing a good rocket, you can get one off the Starport (or mod your game for OP engines). But the base game would have both challanges.

And each of those (bar the mainsail, which had its own problems) were complained about before ARM was even announced. Giving us complainers all something even worse to complain about is not the way to stop complaints. By the same token, several underperforming engines were deservitively buffed, like the Ant and Ion, but the Mk 55 is just as underperforming as the 48-7s is overpowered, and neither was fixed. The Lv-N is in a class of it's own because there are only 2 high efficency space engines- but with the buff to the ion's power, I expect the Ion to start being a realistic choice in comparison- less thrust certiantly, but even more efficient, with other engineering problems like power management. Another engine covering the area between the Nerva and the other LV series, something with 600 ISP but a better TWR than the nerva (heck, you could rework the Ant engine into this! so it isnt competing with RCS ports anymore) would round out the curve and make LV-N engines a real choice. The mainsail's problem was the same one the nerva has- it was on the curve, but so far from it's neibors that there was no choices to be made- If you needed more thrust than a skipper, either you stacked a dozen or so LV30s together to get the thrust you needed, or you got a mainsail. With the addition of the LFB, the Stock Rebalance proect has actually reduced the power of the mainsail, giving you a more efficient engine than the (nerfed) LFB, that has more power than a skipper, to give people more choices. Asparagus is the tricky one, because on paper, it IS the "one true staging." The Shuttle External Tank was the first crude appproximation of this, but the idea has been around for over 50 years. The best we can hope for in KSP is to mimic the drawbacks as well as the advantages- fuel flow momentum, and heavy and expensive pumps- but even in real life, SpaceX is attempting to overcome these difficulties with it's heavy lift designs.

I'd have preferred a 1m shuttle engine and a 3m to 2m+8x 1m adapter. Would have meant being able to build any number of designs with the shuttle engine, without the current mess. of strictly-better-than clusters.

On the D&D forums I go to we have something called the Stormwind Fallacy. "If it's not broken because you can fix it with houserules (mods), it's still broken."

Using the mun to capture into kerbin orbit, however, works just fine.

I stacked 8 engines on top of each other, each with enough fuel that when I got to them, the rocket would have a TWR between 1.4 and 1.5. I then launched straight up, apparently around dusk- and dove into the sun.

As the stock rebalance project shows, the answers to your questions are "Yes" and "Because they're bigger." Being balanced to the same curve doesn't mean they're on the same place on the curve. In the Rework, the SLS cluster engines go past the mainsail as "high thrust low efficiency" engines, suitable for lifting a ginormous rocket to 10-20km before staging, where vacuum ISP starts being a significant factor for the second stage.