So it seems we're getting a Vernier and OMS engines.

[Whirligig Girl]

Vernier engines are small, high gimbal steering engines. I'm really hoping for roll control. THe OMS seems to be related to SpacePlanes, like the Shuttle, as I know Shuttles and Spaceplanes are going to be reusable and good for that in the next update. Here's the Reddit Thread I posted this about.

[problemecium]

I was a little mystified when I saw that in the devblog. I always thought the tiny orange Rockomax engines were verniers / OMS. And that the Sepratrons were ullage motors...

[cantab]

Well it's what you use them as. On my Moho lander the radial ants are the main ascent engines. On a bigger ship you might use them as vernier engines to help make the fine corrections for gravity assists (though using the thrust limiter on the main engines is often just as effective).

I wonder if it means we'll get LFO engines that are linked to the RCS controls, or monoprop engines following the normal throttle? That would be nice, you'd have the option of simplifying your ships to just use one type of fuel.

[Cmdr. Arn1e]

I was a little mystified when I saw that in the devblog. I always thought the tiny orange Rockomax engines were verniers / OMS. And that the Sepratrons were ullage motors...

On checking Wikipedia, I have found that they pretty much are Ullage motors... just people use them to push spent parts away from their rocket, instead of using them as an in-between quick burst of speed (to maintain Apoapsis or similar while still in-atmosphere)...

What I thought at first I'm not going to repeat, as I was totally wrong, and is a reminder that I should always check facts!

EDIT:

monoprop engines following the normal throttle?

I thought they did... unless it's either MechJeb or KAC doing it for me... Doesn't always seem to work though...

[Garek]

On checking Wikipedia, I have found that they pretty much are Ullage motors... just people use them to push spent parts away from their rocket, instead of using them as an in-between quick burst of speed (to maintain Apoapsis or similar while still in-atmosphere)...

As far as I understand it, ullage motors are needed to restart certain types of rocket engine in microgravity because they rely on the fuel being pulled towards the bottom of the tank either by gravity or inertia oposing thrust. But (stock) KSP doesn't implement that. As always with these things there is a mod, Engine Ignitor, which in certain cases requires the proper use of ullage motors to relight engines.

[the_bT]

I don't think we will ever need to place ullage engines in stock KSP. That would make things awfully complex. Even if it is not that hard to a concept to grasp, how would you ever convey to a player that some engine is deprived of fuel X not because said fuel is absent but because it currently chills in a corner of its tank on the wrong side of the rocket...

Hopefully we get something rocket engine like that works with RCS input. I'm sick of placing 20 rcs blocks per end on large cargo SSTO's. I've already tried using the orange Rockomax engines for that but it needs to many action groups.

[The Destroyer]

Bringing this to the attention of anyone in this thread who didn't see this in the Devnotes thread (it was posted later): HarvesteR explained that what is meant by "vernier engines" is engines that respond to RCS control input but consume LFO instead of monopropellant, while "OMS engines" are engines that respond to main throttle control but consume monopropellant instead of LFO. The names are currently just for development and may be changed later.

Found from reddit.

[cantab]

Excellent, thanks. So yes exactly what I'd just guessed at.

[Rune]

Found from reddit.

That's like, awesome. I've been wanting a "high thrust" monoprop engine for probes for a long time, and verniers will simplify upper stages and/or big rockets.

Rune. Anything reducing part count and increasing simplicity is welcome.

[Whirligig Girl]

Well, I was kinda hoping for a steering rocket, but these are good too.

[problemecium]

Ah. I actually started wondering if that was the case myself. It'll be nice to have, although it makes my feeble efforts at making a mod for it vain. :\

[karolus10]

I'm Actually a big fan of having (but maybe not set as default as it may be tricky in few engines configurations) roll control within engine gimbals, especially with twin engine clustering.

RCS with tweakable axis (like with fins now but also with translation axis settings) could be very useful, so you could put RCS thrusters only for roll control in lower stage of the rocket.

Also I would like to see OMS thusters and other hypergolic (AKA RCS fuel) engines of different sizes starting with LV-1 engines family, I guess that it would make a lot of sense to use such engines that way and made larger RCS tank quite useful.

Edited June 1, 2014 by karolus10

[MKI]

Adding Verneir thruster engines seems like an interesting addition. I feel in this game it could easily fill the niche of an RCS fuel based engine with high gimbal, but really the dev's can change it to really anything since its definition is rather vague.

Now OMS engines on the other hand intrigue me. It could mean anything from a new effecient space engine, or an actual Shuttle like OMS engine. Which points to how Spaceplanes will become more relavant in the future. Especially with reusability being tossed around. Now the one thing this really points to is maybe a new High gimbal Shuttle engine? As its easier to make an SSTO than a asymetric Shuttle System with the current stock parts.

[LethalDose]

With the addition of asteroid redirect missions, I think there's a big niche to be filled for power powerful attitude control thrusters, so I'm pleased to see the vernier engines added to the game.

I get the symmetry of adding MP engines controlled by the throttle. Don't think there's as much of a niche for that engine as there is for the vernier engines, but better support for small MP-only vehicles will be interesting.

I'm glad they're adding these parts, it just seems weird that the first place we hear about these engines is from the new intern's post.

[Whirligig Girl]

I'm Actually a big fan of having (but maybe not set as default as it may be tricky in few engines configurations) roll control within engine gimbals, especially with twin engine clustering.

RCS with tweakable axis (like with fins now but also with translation axis settings) could be very useful, so you could put RCS thrusters only for roll control in lower stage of the rocket.

Also I would like to see OMS thusters and other hypergolic (AKA RCS fuel) engines of different sizes starting with LV-1 engines family, I guess that it would make a lot of sense to use such engines and made larger RCS tank quite useful.

https://lh3.googleusercontent.com/-s92vP2nhvxQ/UeHp2pG7h4I/AAAAAAAACSQ/oXLL3G8M2Cg/w900-h600-no/SharedRCS.png

KSP Fuel is Monoprop, not Hypergolic. Hypergolic Fuel is a biprop that spontaneously ignites, and most real RCS engines use this. The Space Shuttle's OMS used it's RCS Fuel, Hydrazine and N2O4

[Whirligig Girl]

Hoping Vernier engines are unlocked before RCS engines, because the Atlas rocket used Vernier engines and it ran from the regular fuel supply.

[LethalDose]

KSP Fuel is Monoprop, not Hypergolic. Hypergolic Fuel is a biprop that spontaneously ignites, and most real RCS engines use this. The Space Shuttle's OMS used it's RCS Fuel, Hydrazine and N2O4

This is correct, but could be misunderstood. Hydrazine (N2H4) and DNT (N2O4) are a hypergolic fuel combination. However, hydrazine by itself is also a monopropellent when passed over a catalyst. In fact, according to wikipedia, hydrazine the most common monopropellent used in rockets. Though, that does not mean that mean most real RCS engines are monoprop hydrazine engines.

The point being, hyrdrazine is both a hypergolic fuel (when mixed with DNT), and a monopropellant (by itself, with a catalyst)

Edited June 2, 2014 by LethalDose
DNT chemical formula was N2O2, now correctly N2O4

[karolus10]

KSP Fuel is Monoprop, not Hypergolic. Hypergolic Fuel is a biprop that spontaneously ignites, and most real RCS engines use this. The Space Shuttle's OMS used it's RCS Fuel, Hydrazine and N2O4

Well, I assume that RCS propellant in KSP can be considered as hypegolic bi-propellant (mono-propellant it's possible as well but it's not a very good idea) as different fuels wasn't implemented into the game (for example NTR's still use liquid fuel and oxidizer), and RCS stay pretty much untouched since it was introduced - back then "fuel" was a single resource for rocket engines as well.

I call it hypergolic, because it's plausible that it's some imaginary hypergolic fuel mix are used now for RCS and maneuver thrusters.

Edited June 1, 2014 by karolus10

[NERVAfan]

That's like, awesome. I've been wanting a "high thrust" monoprop engine for probes for a long time.

Me, too. I kind of thought the "ant" engines should burn monoprop (and I think I've seen that suggested before).

[NERVAfan]

This is correct, but could be misunderstood. Hydrazine (N2H4) and DNT (N2O2) are a hypergolic fuel combination.

Dinitrogen tetroxide is N2O4 (a dimer of NO2, which is part of photochemical smog air pollution... N2O4/NO2 actually exist in an equilibrium depending on temperature). Otherwise correct.

[Nuke]

roll control doesn't sound that hard to do. tilting an engine on x or y gives you yaw an roll control, you can generate a quat to store those rotations and multiply them together, and this gets applied to both the gimbal model and the thrust vector. make a 3rd quat to store a rotation for the roll axis, except this axis is going to be between the center of gravity and the gimbal model origin, but flattened on the local z axis. this can just be multiplied into the final rotation. this is then applied to your final thrust vector. simple maths. im supprised squad didnt bother trying to figure that out when it did its gimbal code.

[LethalDose]

Dinitrogen tetroxide is N2O4 (a dimer of NO2, which is part of photochemical smog air pollution... N2O4/NO2 actually exist in an equilibrium depending on temperature). Otherwise correct.

Was a typo. Now corrected.

[Kasuha]

I wonder if Vernier/OMS will be new engines or if they will be just tweakable option on some of existing engines/RCS thrusters. In either case they will definitely be welcome, current RCS is a bit weak for SLS parts.

[LethalDose]

I wonder if Vernier/OMS will be new engines or if they will be just tweakable option on some of existing engines/RCS thrusters. In either case they will definitely be welcome, current RCS is a bit weak for SLS parts.

The "announcement" about these engines from the intern said he was working on new models (or had finished new models) for the OMS and Vernier engines, so it sounds like we're getting new parts.

Tweakable options for older parts would be cool, too.

[Franklin]

cannot wait for vernier engines. but like what was said, the LV-1s set to an action group have been the go-to for this need thus far. so beyond a shift to different fuel needs, i don't quite see where the public demand is.

i'm hoping to see presently un-simulatable needs fleshed out sooner rather than later. like where is the stock cargo bay, nevermind a rotary joint or two.