Zorg

Oh no! Pentaborane????

Mostly finished M1. A few tweaks still needed and the emissives for all 4 engines still pending but they're approaching completion Featuring Beale's Cardboards Jeb for scale.

Fixed both on github now. I cant reproduce this issue. Tested both versions of the engine.

Please let us know specifically which engines?

Glad you're enjoying it! And welcome to the forums

Two more engines mostly finished texturing: Pratt & Whitney RL20-P3 If you missed the earlier discussion this was Pratt & Whitney's first attempt at a staged combustion cycle design. It was vaguely mentioned in at least one Saturn improvement study as a drop in J2 replacement and the vac version has been tested and found to cleanly fit in mount truss of Cobalts upcoming SII stage. While the engine was never made, ultimately it seems more real than the mysterious HG-3 program which was more a study of various components than a specific engine design. So we're giving you this instead of HG-3. Pratt & Whitney XLR-129 Again if you missed the earlier discussion, the XLR129 was a direct successor to the RL20. Also staged combustion and a similar powerhead where the turbos and preburner connect to a central chamber above the combustion chamber. However instead of a Y shape, this uses a triaxial arrangement and also adds low pressure pumps/inducers upstream of the main turbos. (similar to RS30 as well). The XLR129 was originally meant for a B52 launched rocket powered boost glide spyplane and after that got cancelled P&W uprated it and tried to push it for the shuttle program where it did not succeed against Rocketdyne's RS25. This will be capable of running with the nozzle extended or retracted and will be availabel in 1:35/75 and 1:80/144 expansion ratios.

Little preview RS30 Advanced Space Engine for anyone who missed it. This is only slightly larger than an RL10A4 and will fit on a Dual Engine Centaur mount. transpiration cooling mini nozzles

There should be no B9 errors with an up to date BDB in KSP 1.8.1 onwards. Would need to see a screenshot of the error first.

The required functionality already exists in Nerteas deployable engines exactly as needed, as I said in my previous post. Using DE's "multistage engine" module the XLR 129 will be able to operate with or without the bell extended with different stats depending on your choice. The question is whether we integrate his code and update our plugin with it or add DE as a dependency (decision is for JSO).

Thanks to that particular sound effect goes to @ensou04 author of Rocket Sound Enhancement. The RSE mod itself has great sounding effects but also has a dedicated plugin for handling them in a better way. Actual RSE compatibility for BDB is something I'm hoping to do in the future but it will involve some amount of work so might not happen so soon. Glad you're enjoying the current sfx in the meantime though

It should be light enough but keep in mind its significantly less powerful than the RS25. The shuttle was likely a lot smaller than the final design at the time P&W were still in the competition. It might still be workable and it should be great for generic shuttle like spaceplanes in general but its not a 1:1 replacement for the RS25. I would be curious to see how well it works on SOCK though. I suspect you would need bigger boosters or possibly find a way to squeeze 4 engines onto the orbiter to maintain performance.

As mentioned earlier, was originally meant for a rocket powered boost glide plane (ISINGLASS) and then later for the Space shuttle. No other considerations I'm aware of. But in BDB you're gonna have to get creative. The engine mounting mechanism will be roughly the same footprint as the J2. The booster version has a nozzle diameter of around 1.14m and the vac version 1.59m. Im sure you can find plenty of creative uses for such an engine. Its predecessor the RL20 was mentioned in passing for Saturn upgrades in at least 1 document but the XLR 129 came too late for such considerations I think. It went straight for shuttle after the spyplane was cancelled and then died with the failure to get the contract.

So going back to this and going over the performance figures, it looks like the figures I quoted (465s Isp) were for a version with a 166:1 extended nozzle as opposed to the baseline 75:1 model which most of the docs are dealing with (this was the demonstrator engine). The 166:1 is supposed to be the flight model. The 75:1 ratio model tops out at 450s same as the SSME. Though its sea level Isp is notably higher at 385s vs 366 on the SSME. Anyway this variant is easy enough to do (and efficiently).

The required functionality already exists in Nertea's Deployable Engines. Either we add it as a dependency or integrate the code into the BDB plugin. BDBs own existing deployable engines functionality is a modified version of an older version of Deployable Engines anyway. Its essentially linking deployable engines (animation) with the stock multi mode engine module.

vac performance is 250k lbf thrust (1,112 kN) and from 450s up to 465s specific impulse. For the shuttle it was supposed to be to be uprated to 350k lbf (1,556kN). Exact game balancing isnt decided yet but there are some performance tables and documents here: https://www.alternatewars.com/BBOW/Space_Engines/Pratt_Engines.htm Oh and by the way it was supposed to be able to operate with the nozzle retracted at sea level and deployed at altitude. We're looking at implementing this functionality. Overall its not as powerful as the RS-25 but quite the beast nonetheless and better Isp and optimised better throughout the envelope. Im not 100% sure on this but I believe P&W were out of the running by the time the shuttle had grown in size and that would explain why its noticeably less powerful than the final SSME that we got from Rocketdyne. 512,300 lbf (2,279 kN) Figures above are IRL thrust figures, in KSP they would be 1/4 of that.

And here it is. The XLR 129 Staged combustion cycle engine originally meant for a B-52 launched rocket spyplane called ISINGLASS as mentioned earlier. Derived from work P&W did on the RL20. Further uprated from the original ISINGLASS configuration, it was their losing contender for the space shuttle program. Just like the other 3 engines, (RS30, RL20 and M1) the nozzle extension is transpiration cooled and the upper nozzle and chamber are regen cooled. In this case we have a cool mechanical linkage connecting the coolant feed line that moves with the deployable nozzle.

Oh hmm, i'll take a look at the 405. Pink square must be something else, sign of a broken/incompatible shader. An incorrect version of a some visual mod is my guess. We have a number of AJ10s but not the one for the shuttle which is the AJ10 190. You could potentially substitute something like the Delta K AJ10 118k but it wouldnt look right and Im not sure about how the thrust balance will be on Benjees shuttle. Sticking with reDirects parts is probably wiser. As others have mentioned we dont have an RS-25.

This doesn't sound like quite the right behaviour for this engine. Will take a look.

The fairing bases have colliders and allow surface attach. Since the fairings are the same part, you can place the decal on the base and then use the offset gizmo and slide the decal onto the fairing itself. (technically the fairing sides do have colliders but they dont do anything till flight)

I'm practically speechless. This is astonishing work Benjee

A big part of the reason why we started doing Waterfall configs and indeed made it part of the default package is that they offer much better performance than particle plumes (both stock particles and realplume) thus bringing nice plumes to a wider user base. using both together takes away this performance advantage and makes it worse than using either on its own. Additionally while that example looks nice in many other examples especially sea level plumes, you will likely need considerable additional work done to make sure the particles and the waterfall plumes expand and behave in harmony together. This is work I am definitely not interested in doing. You are of course free to experiment with combining them for yourself but its not an option we will be looking to offer as an official compatibility option. all you need to do is remove the !Waterfall from the :NEEDS[...] in the realplume patches. However our official condition is if WF and RealPlume are installed together, WF for liquid engines and RealPlume for solids.

I always assumed they wouldn't make the 1.7.2 release Will take a bit of time to populate the interiors with props, possibly make a few new props etc. But the good thing is hopefully our new workflow for git should allow us to release more frequently as important content is added instead of waiting for a single big annual update.

Will be fixed in an update in a few days time.

Advanced Engine Development at Pratt and Whitney: The Inside Story of Eight Special Projects, 1946-1971 by Dick Mulready. TJ managed to borrow it on my behalf to check the data and someone else had posted the only RL20 images from it on twitter a while back.

Yeah, the engine in its SL version is quoted as 250k lbf at sea level. Alternatewars quotes 265k lbf for vac performance of the SL version but I havent found the original source for that figure. Isp figures for the either version arent available but I do have a rough guide based on a theoretical RL20 performance graph at various expansion ratios in a book. In Ksp terms this means the J2 SL as we have it configured produces 193kN at SL and 234.7kN in Vac. The RL20 SL would be 278kN at sea level and 294kN in Vac. Being an engine that was never built we might not take this as gospel and might tweak things for balance taking into consideration where the XLR129 and the RL20 vac fits as well.