KerPollo 8 Apollo Replica

[John FX]

Wow, you keep on putting more work on this... delightfully geeky to read about!

Rune. I'm much more dispersed.

Thank you, it`s nice to know someone reads the thread...

Edited April 6, 2014 by John FX

[John FX]

Well I said I would post if anything changes and I`m up to KerPollo 9 now. The A.L.S.E.P. is upgraded, the landing legs are changed, the rover releases more reliably. A few minor improvements. The CM and Lander are still stock. I`ve removed KOS because if you want something to fly it for you then you can use Mechjeb. There are other improvements but I can`t remember them all.

If there is any interest I`ll update the Spaceport with the new version...

[John FX]

I`ve realised I make this craft pretty much for myself and I`m ok with that. Now that there is a hollow ring for procedural fairings, I`ve incorporated it into KerPollo with lovely results.

It seems with 0.24, we are getting bigger fuel tanks so I will update KerPollo with those and limit the amount of non-stock parts to the fairings and stupid-chris`s realchutes.

KerPollo is hardly modded at all and soon it will be less. I will never mod engines. I don`t even use clipping. I`m looking forward to the day KerPollo is stock.

Here are some images of the latest launch. I`ve improved the ALSEP and gone back to the larger legs.

Javascript is disabled. View full album

The munar insertion stage is now controllable after ejection so it can be impacted onto the munar surface for Science! and to better replicate the Apollo mission profile. The CM has been enlarged with Fairings to make it the right relative size for the lander, which in turn is close to the relative size for a Kerbal although it is truly dependent on the size of the smallest two person pod and the legs raise it too high due to the rover. That and the 5 x1500,5x220,1x220 engine formula have dictated a lot of the design.

Next I plan on trying to reduce the size of the rover, currently it seems a bit large for the scale of the lander and it`s hard to get it out from under the lander meaning the lander sits too high.

Now I have a proper interstage, I shall be fitting it with ullage motors that are the right relative power when compared to the ones used on the Saturn.

Ullage Motors

The S-IC/S-II interstage adapter contained four solid propellant ullage motors to provide artificial gravity by momentarily accelerating the second stage forward after first stage burnout. This moment of forward thrust made certain the liquid propellant was properly positioned to be drawn into the pumps prior to starting the second stage engines. The ullage motor nozzles were canted 10 degrees to reduce exhaust impingement against the interstage structure.

Similarly, the S-IVB stage contained two solid propellant ullage motors to provide positive stage acceleration during separation, to position the liquid propellant toward the aft end of the tanks, and to force propellant boil-off vapors to the forward end for venting. The S-IVB ullage motor assemblies were jettisoned after use. According to Thiokol, the mass of each TX-280 ullage motor was 29.7 lbm.

From Technical Information Summary, Apollo-11 (AS-506), Apollo Saturn V Space Vehicle, Document No. S&E-ASTR-S-101-69, June 25, 1969:

S-II Aft Interstage

Ullage motors: 4 each

Thrust: ≈23,000 lbs per each

Burn time: ≈3.5 sec

S-IVB Stage

Ullage motors: 2 each

Thrust: ≈3,400 lbs per each

Burn time: ≈4 sec

Using the same reduction of 1000lbs of thrust to 1kn of KSP engine, I need 4 engines of 22kn each to run for 3.5s and two 3.4Kn engines to run for 4 seconds.

I`ll keep you posted. If anyone wants a craft file, just post here.

Edited March 20, 2014 by John FX

[Majorjim!]

WOW John FX, Your really going deep with the details!

I'm certain this would get more attention if it was 100% stock though.

MJ

[John FX]

WOW John FX, Your really going deep with the details!

I'm certain this would get more attention if it was 100% stock though.

MJ

As am I but until stock fixes the insta-chutes, gets fairings and has some larger tank sizes (0.24 we are told, hooray!) then I`ll have to use some mods. The goal is to be stock of course.

TBH I`m tempted if we get bigger tanks...

The fuel margins are getting there.

Figures are from the latest launch.

Stage 1 drops at 23km stage 2 drops when Ap is 72km (edge of space) and Pe is 9 (will autodelete).

The S-IVB has 961 Dv in LKO, a FRT needs 872. There are images of the S-IVB dumping fuel after lunar insertion so I`ve left about 90Dv which should allow it to be impacted on the Mun for SCIENCE!

If you orient to rad+ when separating the Eagle from the S-IVB and your Munar Pe is low enough then the separation thrusters will automatically send the spent stage on a collision course with the Mun.

The measured g-force matches pretty close to the Apollo launch graph and the lander has a TWR of about 2 on Mun nearly empty (0.3 Kerbin) like the Eagle. There is plenty of fuel for descent to allow for options when landing (you have to start about 65km from where you want to land at about 7km altitude), there is about 150Dv margin of error.

I`ve noticed the many many ALSEP designs so I may try to replicate a few of those. I`ve made the central station, RTG (hehe) and LSM. I may try to make the PSEP and SIDE, not sure if I have room though.

Always more to do.

Edited March 21, 2014 by John FX

[Majorjim!]

As am I but until stock fixes the insta-chutes, gets fairings and has some larger tank sizes (0.24 we are told, hooray!) then I`ll have to use some mods. The goal is to be stock of course.

TBH I`m tempted if we get bigger tanks...

The fuel margins are getting there. Stage 1 drops at about 20-23km stage 2 drops when Ap is 65km (edge of space) and Pe is -20.

There are images of the S-IVB dumping fuel after lunar insertion so I`ve left about 95Dv which should allow it to be impacted on the Mun for SCIENCE!

The measured g-force matches pretty close to the Apollo flight graph and the lander has a TWR of about 2 on Mun nearly empty (0.3 Kerbin) like the Eagle. There is plenty of fuel for descent to allow for options when landing (you have to start about 65km from where you want to land at about 7km altitude), there is about 150Dv margin of error.

I`ve noticed the many many ALSEP designs so I may try to replicate a few of those.

Always more to do.

This is very impressive mate. Keep up the good work. I will keep an eye on this.

MJ

[John FX]

One of the next things to do is convert to the latest version of stretchy tanks,

[John FX]

KerPollo 8 is released.

[John FX]

Javascript is disabled. View full album

The new ejection system I`ve been working on for Gumdrop.

Edited April 13, 2014 by John FX

[thunderstar]

it's for stock ksp right? i mean not for RSS

[John FX]

it's for stock ksp right? i mean not for RSS

Yes, it is not built for FAR, RSS or any other physics altering mod. It`s for `stock` ksp.

You should just need stretchy tanks, procedural fairings and realchutes to load the craft.

When we get bigger tanks then hopefully just procedural fairings and realchutes.

Please let me know if I have left any odd mechjeb units, engineer flight units or anything else by accident and I`ll remove them.

[thunderstar]

thanks, its great and i have tested it with FAR, it works but you have to be more careful while flying it.

[John FX]

thanks, its great and i have tested it with FAR, it works but you have to be more careful while flying it.

That`s nice to know. I wondered if there was enough Gimbal to cope with FAR.

KerPollo 9 will be released soon (next week or so when I have time) with the new escape tower and stock fuel tanks for the S_IVB and CM. The new tank looks good with the lack and white checkerboard as does the escape tower. The escape system has a shield for the crew pod also which is released when the chutes are activated. Fuel levels will need refining again

[John FX]

With 23.5 there is `stuff` meaning a delay in KerPollo 9. Now the craft can be launched with correct gimballing of the four outer engines instead of the centre one, just like Apollo. The manned pod has a cover which is ejected with the escape tower, the S-IVB is now made from one of the new tanks although it has about 600 extra liquidfuel so that will need adjusting and I am completely redesigning the lander.

Gallery to follow.

[John FX]

I`ve just used RasterPropMonitors to launch and get into orbit around Mun in KerPollo completely IVA (except for a little node making in the map)

I landed normally (not IVA) because I was testing the new lander. Also I am still figuring out the best places for the cameras. It has too much fuel for its current weight but it currently has no rover I shall keep an eye on that and adjust once the weight is closer to finalised. The ascent stage launched cleanly and attained orbit with 175m/s left. I shall be reducing the fuel in that section also.

This is the new lander on its maiden voyage to Mun with IVA goodness.

Javascript is disabled. View full album

[John FX]

The new lander is a design departure from the methodology that has brought the craft to its current state.

Previously the Rover decided the scale etc of everything else and up to now has not done too bad a job but I feel the limits have been reached and so I redesigned the lander to fit inside the fairings and I will now have to come up with a redesigned rover to fit inside. There is a bit less space under the skirt but the redesign is better than the old one.

Currently KerPollo is pretty much Apollo 11. I will be adding a rover to flesh out the missions which will turn it into a later Apollo (with extra retro and ullage, they got taken out) but that will be a little while I think.

Also the current lander is very tough. I have (crash) landed on Mun at 20m/s and whilst it bounced a bit, nothing exploded and all the legs stayed on. (seemed a bit fast for nothing to happen to me, maybe the upgraded nodes are a little too `upgraded`)

It also seems that each KerPollo has a guest Mod. Sometimes they stay for later versions, sometimes not. Realchutes is staying, kOS is gone but the new golden (in my eyes) mod is RasterPropMonitors. They just make IVA better (by a LOT)

So the next version of KerPollo (I`m thinking of changing the name, loads of people use kerpollo, any ideas?) will have a bunch of cameras to allow a full IVA mission using RasterPropMonitors. Some will be in classic places, like the shot down the rocket for launch, watching the interstage ring separate and fall away and other will be functional, front and back of each craft and of course landing and docking.

Well, here it is. I`ve decided on the name Gumdrop. It was used for one of the first Command Modules. All the other names seemed a bit too serious. It`s still a stock lander although I have put a few rasterpropmonitor cameras on it to help with IVA landing.

Edited April 14, 2014 by John FX

[montyben101]

Could you taper the bottom of the second stage a bit like this:

That would look great

Kerpollo 8 looks awesome btw i love the lander

Edited May 11, 2014 by montyben101