Need new Monoprop engines (bigger)

[schwank]

Hey all. Now that we have some sweet solid boosters for the shuttle replicas we need the OMS system to match. 

How about a better Monoprop engine that's much bigger? And also maybe an odd shaped payload bay or mono tank that can be shaped like the OMS/RCS fuel tanks on the aft of the orbiter.

Really like the new design on that big solid (not so much the Pollux but the Clydesdale looks awesome). 

Thanks KSP guys!

[PositronLance001]

Agreed. The O-10s are smaller than a kerbal. 

Now look at the Shuttle OMS engines.

,

[schwank]

Nice comparison thanks! 

I will say they do work though. I built a shuttle last night and without a major payload it was about a .08 TWR which did get the job done. But a bit bigger would be nice, and maybe attachable to a node instead of a radial engine.

Also I used an emptied supersonic intake LF tank and it ended up looking ok as an OMS pod.

Edited October 24, 2019 by schwank

[The Dressian Exploder]

Time for the 'There's a mod for that' cliche! I'd throw my lot in with RLA reborn.

[Tweeker]

The OMS engine in KSP is all goofed up, 

It is based on the AJ10-190 Engine, but it gets a few things wrong. Most importantly here is that it is a bi-propellant hypergolic engine, not Monopropellant. Its ISP should be much higher, 315. And its thrust should actuall be lower.

 You mentioned having a TWR of .08, the Orbiter weighs about 240,000 at launch and 178,000 empty. Each OMS engine is 6,000 Lbf,  and if you suppose an on orbit mass of 200,000 lbs your TWR is .06.

The engine  could stand to be a little bigger, but shouldn't be much bigger than a kerbal

 

The pods you show above, from the shuttle are actually the AJ10-137 OMS engine, the aft RCS thrusters, and about 25,000 pounds of Fuel.

What we actually need is for the Puff to be Bi-propellant, with a better ISP, and maybe a fuelled pod to stick on the sides of Shuttles, or for there to be a variant of the engine plate with OMS pods.

[schwank]

On 10/25/2019 at 9:38 PM, Tweeker said:

The OMS engine in KSP is all goofed up, 

It is based on the AJ10-190 Engine, but it gets a few things wrong. Most importantly here is that it is a bi-propellant hypergolic engine, not Monopropellant. Its ISP should be much higher, 315. And its thrust should actuall be lower.

 You mentioned having a TWR of .08, the Orbiter weighs about 240,000 at launch and 178,000 empty. Each OMS engine is 6,000 Lbf,  and if you suppose an on orbit mass of 200,000 lbs your TWR is .06.

The engine  could stand to be a little bigger, but shouldn't be much bigger than a kerbal

 

The pods you show above, from the shuttle are actually the AJ10-137 OMS engine, the aft RCS thrusters, and about 25,000 pounds of Fuel.

What we actually need is for the Puff to be Bi-propellant, with a better ISP, and maybe a fuelled pod to stick on the sides of Shuttles, or for there to be a variant of the engine plate with OMS pods.

Nice pic. I guess if we wanted the OMS engine to be bi-prop it would work fine with terriers or a cheetah. 

I want to correct my original post and say my current TWR on the dual puff is .11 which is actually very adequate and seems decently realistic with the amount of prop I've got on there it gives me about 450 DV for on orbit activities.

Here's the craft file if you guys are interested

https://kerbalx.com/schwank/Shuttle-KTS-41

[qzgy]

On 10/24/2019 at 2:09 AM, schwank said:

How about a better Monoprop engine that's much bigger? And also maybe an odd shaped payload bay or mono tank that can be shaped like the OMS/RCS fuel tanks on the aft of the orbiter.

Depending on how much you care, you could install a mod to do so, or you could try your hand at making that weirdly shaped tank using stock parts, clipping in fuel tanks where necessary and other weird random parts. I know that there are very nice shuttle replicas out there (this one seems pretty nice https://kerbalx.com/SpaceTrashCan/Space-Shuttle) that do exactly that. Radiators and intakes are common.

[tater]

More importantly, we'd need a reason to want such engines. KSP really needs multiple propellants, with pros and cons.

[DStaal]

I'll add for the request for more monoprop engines.  I use the ones from Near Future all the time.

As for reasons why to want such engines: For me, it's a bit of design simplification, and a bit of headcannon.  The headcannon is that I tend to treat LFO engines as 'limited starts' - I don't actually play with anything limiting it, but if a ship is going to need to do a large amount of arbitrary burns, I'll avoid LFO.

The design simplification angle is easier to explain: I often design ships with 'orbital' stages which mainly perform a redezvous to some other ship/station and then deorbit again.  Such a ship needs only a small amount of dV, but it absolutely must have RCS.  If the main engine is LFO, that means two sets of tanks - one for the main engine, one for the RCS thrusters.  While a monoprop main engine means the two systems can share a tank, saving design complexity, part count, and mass.