Thuds Are Beautiful

[Moesly_Armlis]

Don't use the Thud because when I made something with it, I blew up the whole space centre. IN CAREER!!!

If you do take on the challenge to use the Thud there is rewards. Designing in an extreme hard career within the 18 t/30 part limit is challenging. Landing a kerbal on Mun and returning science is even more of a challenge.

The Payload:

The payload is a lander that can have its range extended by docking fuel containers in low Kerbin orbit. The weight of this payload is 2375 kg and that includes the fuel in the FL-T200.

Mk1 Command Pod, Materials Science, Mystery Goo, Thermometer, three LT-5 Micro Landing Strut, 48-7S Spark Engine, Z-100 Battery, Clamp-O-Tron junior is the lander and the Fl-T200 and another Clamp-O-Tron junior make up the fuel portion of the payload

The Lifter:

Five FL-T400 fuel tanks that are dropped during flight and another FL-T400 with Twin Thuds attached. The five empty FL-T400 tanks weigh 1.25 tonne and represent 7% of the total mass.

This vessel is a challenge to pilot and reach orbit but is so far the only design that is capable. The Thuds make this design function.

The best I have done with the Litterbug Lifter is use 4100 m/s delta-V to reach low Kerbin orbit. I would say it is a challenge to lift the payload and use any less.

The booster total delta-V is 3747 m/s and the payload has 1608 m/s and uses 353 m/s to reach LKO with 1255 m/s remaining.

After docking another FL-T400 in LKO this lander can easily reach Mun, land and return science to Kerbin. The final part of this Mun mission is rendezvous with the return vessel.

Litterbug Lifter

[KerikBalm]

I almost used them for my Moho mission... almost...

My final ship design ended up looking like this:

Obviously, getting it into orbit would be a challenge.

So, I decided I'd loft it in two or three peices.

The bottom component is a beefy mostly chemical ejection stage, with excess LF to allow it to retroburn after separation, stay in kerbin SOI, aerobrake and circularize for refueling and reuse (I got tired of LV-N tugs with long burn times)

I decided to loft that thing first.

The KR-2L doesn't produce that much SL thrust, and the LV-Ns are worthless at sea level... a slightly heavier earlier incarnation didn't even have a TWR >1

It wasn't going to SSTO itself into orbit (I'm doing fully recoverable/reusable designs now... well... recover everything except payload fairings.) with that sea level thrust.

So, my options were radially detaching boosters (won't recover due to despawn, unless i take it to orbit)... or something put on top of the open docking Sr. node with radial engines.

I put some fuel tanks tapering to an aerodynamic tip (with parachutes and a probe core) on top, and did 6 radial thuds.

Thuds have good Sea level Isp... and higher up I shut them down and let the KR-2L (a relatively good vacuum engine) and the LV-Ns do the rest of the work.

Then I detached, deorbited, and recovered the Thud powered nosecone...

Except that was in my sandbox "mission simulation" save...

The thud is good for work around 1 atmosphere... airbreathing engines also work well there... and I delivered that entire mission stack to orbit in 2 launches of a SSTO spaceplane instead.

[Wanderfound]

Also handy for low-tech spaceplanes:

[juanml82]

Usually, when I want radially mounted engines, I use aerospikes on radially attached fuel tanks. But the Thuds are always worth a look in those situations. While the aerospikes have better isp, they have no gimbal

[KasperVld]

I'm glad to hear the balancing tweaks for this engine have worked out. In my experience their gimbal range is excellent, and I've mostly used them in cases where I wanted a little more directional control over my rockets