Stock Payload Fraction Challenge: 1.0.5 Edition

[g00bd0g]

[quote name='Red Iron Crown']g00bd0g, that looks like a fine spaceplane that is quite practical, but your album does not meet the challenge guidelines. Specifically, the mass of the vessel before launch must be shown, the mass of the payload in orbit must be shown, and the craft cannot dock or other wise interact with any other vessels (though you can do what you like with the payload afterward).

I encourage you to document another flight so I can add your plane to the leaderboard. :)[/QUOTE]

Pretty sure I have the required documentation in that album. Here's the specifics. I did not eject the payload before docking, but I did show it in orbit with all resources shown. So you can be sure I did not add/remove anything in the process of docking. Please let me know if this is OK, if not, I will refly, I can always improve anyways :)

Total vehicle mass at launch 143.1t
[IMG]http://i.imgur.com/aoU5D8q.png[/IMG]

Vehicle mass minus payload 106.6t. 143.1-106.6 = 36.5 payload
[IMG]http://i.imgur.com/1Vf5fsD.png[/IMG]

Full payload in orbit
[IMG]http://i.imgur.com/vVCtCFh.png[/IMG]

Full payload detached and being moved to KSS
[IMG]http://i.imgur.com/eFwBboX.png[/IMG]

[tewpie]

Turns out automated landings are a LOT harder to program for than automated takeoffs.

I present Scarab mk6 (.craft):

Takeoff Mass: 274.17t
Payload Mass: 153.00t
Payload Fraction: 55.80%

Some highlights:
- Single LV-N and 11x RAPIERs.
- Uses only 2 shock cone intakes, they are a bit OP.
- Uses the new mk3 engine mounting plate and tri-adapters for significant drag reduction (see the triforce in the back?).
- (Unclipped) Rapierspikes for further drag reduction. Restricted gimbals to avoid damage.
- Minor clipping and offsetting for wet/dry CoM balance.
- Uses shielded docking port and cargo bay doors as pseudo airbrakes during landing.
- Flight is almost completely automated via kOS. Only manual portion is jettisoning the cargo (and only because I needed time to take screenshots).

Edited January 7, 2016 by tewpie
Fix formatting after forum upgrade

[Johould]

Is an "SSTO" allowed to use launch clamps? This came up while trying to stabilize Mikki's Monster - If it's only needed to survive the initial physics jerk, a clamp is cleaner than more landing gear.

[tewpie]

[quote name='Johould']Is an "SSTO" allowed to use launch clamps? This came up while trying to stabilize Mikki's Monster - If it's only needed to survive the initial physics jerk, a clamp is cleaner than more landing gear.[/QUOTE]

I think so, the only requirement is that all parts be recovered, and clamps are automatically recovered.

[Johould]

Oh right, it is called "Recoverable" rather than single stage.

[g00bd0g]

[quote name='tewpie']Turns out automated landings are a LOT harder to program for than automated takeoffs. :cool:

I present [B]Scarab mk6[/B] ([URL="https://www.dropbox.com/s/kvrsbfghg3vug5j/Scarab%206.craft?dl=0"].craft[/URL])

[url]http://imgur.com/a/Nmxki[/url]

Takeoff Mass: 274.17t
Payload Mass: 153.00t
Payload Fraction: [B]55.80%[/B]

Some highlights:
- Single LV-N and 11x RAPIERs.
- Uses only 2 shock cone intakes, they are a bit OP.
- Uses the new mk3 engine mounting plate and tri-adapters for significant drag reduction (see the triforce in the back?).
- (Unclipped) Rapierspikes for further drag reduction. Restricted gimbals to avoid damage.
- Minor clipping and offsetting for wet/dry CoM balance.
- Uses shielded docking port and cargo bay doors as pseudo airbrakes during landing.
- Flight is almost completely automated via kOS. Only manual portion is jettisoning the cargo (and only because I needed time to take screenshots).[/QUOTE]

People are saying SSTO's are nerfed in 1.05, and here you are upping the records even more. Sweet engine array setup.

[Red Iron Crown]

g00bd0g: This pic, before the docking, shows 4013 LF and 3932 O. Subtract out the 2880/3520 in the orange tank payload and that leaves 1133 LF and 412 O in the ship. This pic, after undocking, shows 1317 LF and 607 O in the craft, so it's hard not to think that some resources were transferred. I'm sorry but I have to ask you to repeat the flight without docking the plane for eligibility.

tewpie, that's an innovative entry! Clever to limit the gimbals to keep unclipped rapierspikes working within the new rule, and that cluster using the Mk3 adapter is something new. Great job on automating the whole thing with kOS, too. A fine entry, added to the top of the board.

[g00bd0g]

[quote name='Red Iron Crown']g00bd0g: This pic, before the docking, shows 4013 LF and 3932 O. Subtract out the 2880/3520 in the orange tank payload and that leaves 1133 LF and 412 O in the ship. This pic, after undocking, shows 1317 LF and 607 O in the craft, so it's hard not to think that some resources were transferred. I'm sorry but I have to ask you to repeat the flight without docking the plane for eligibility.
[/QUOTE]

Well I'll be darned, I don't remember transferring anything but it was late at night and the numbers don't lie. I've already greatly improved the goose and I'll resubmit. Good eyes man :)

[g00bd0g]

OK, for reals now... This time I have video :) Non-stop and un-edited from start to finish.

Introducing, the Goose x6. The Goose x8 was was overkill for a single orange tank, so I trimmed the fat and got a much better mass ratio.

Mass is 116.4t at launch, payload is 36.5t. 31.34% payload fraction.

[video=youtube;7CHarS7ZxEw]https://www.youtube.com/watch?v=7CHarS7ZxEw[/video]

[Slugy]

[quote name='Val']Thank you :D

I'm not sure I want bigger wings. A single pair of shuttle wings are comfortably enough for crafts up to 100 t take-off weight, and 150 t as long as you don't plan to land with cargo or lots of fuel left. At least for configurations were you have take-off weight at no more than 22 t per RAPIER.

But I would like a set of larger, thicker modular wing panels, so we can build larger wings. It's always bothered me that the shuttle wings don't look so good when combined with other wings or just trying to use multiple pairs.

I haven't tried. Haven't needed to, with the parts I use.[/QUOTE]

We have different approaches to winged craft :)

The current wings are ok for a shuttle type craft (chunky glider), or a Skylon style craft (high TWR), but they are undersized for a large plane imho, and building up large wings, and tweaking angles is both fiddly and ugly.

By way of comparison a 100t craft with 4 rapiers and 2 big S wings will only just scrape into the air at the end of the runway (with luck and hard elevator use) - that is roughly similar to Concorde take off speed, runway length, and TWR (at the low speed). More engines helps - but the TWR is very high for an aircraft then. A longer runway would help too.

Bigger wings, and bigger modular panels would both be welcome, assuming procedural parts are never going to be introduced to stock.

[COLOR="silver"][SIZE=1]- - - Updated - - -[/SIZE][/COLOR]

[quote name='tewpie']

Takeoff Mass: 274.17t
Payload Mass: 153.00t
Payload Fraction: [B]55.80%[/B]

Some highlights:
- Single LV-N and 11x RAPIERs.
- Uses only 2 shock cone intakes, they are a bit OP.
- Uses the new mk3 engine mounting plate and tri-adapters for significant drag reduction (see the triforce in the back?).
- (Unclipped) Rapierspikes for further drag reduction. Restricted gimbals to avoid damage.
- Minor clipping and offsetting for wet/dry CoM balance.
- Uses shielded docking port and cargo bay doors as pseudo airbrakes during landing.
- Flight is almost completely automated via kOS. Only manual portion is jettisoning the cargo (and only because I needed time to take screenshots).[/QUOTE]

A great fraction, but it does have quite a lot of clipping of tanks, engines, and adaptors at the back: Isn't this against the rules?

I'm also curious as to how offsetting the tri adapters is regarded - it's clever but doesn't that fool the aero model into treating them all as attached to the bottom nodes?

The automated flight is very cool too, but it would be nice if it was flyable by human hands. Edited November 26, 2015 by Slugy

[Red Iron Crown]

[quote name='g00bd0g']OK, for reals now... This time I have video :) Non-stop and un-edited from start to finish.

Introducing, the Goose x6. The Goose x8 was was overkill for a single orange tank, so I trimmed the fat and got a much better mass ratio.

Mass is 116.4t at launch, payload is 36.5t. 31.34% payload fraction.

[url]https://www.youtube.com/watch?v=7CHarS7ZxEw[/url][/QUOTE]
Thanks for updating, this one is compliant and I've added it to the leaderboard. I calculated your fraction using KER's kg-accurate numbers, brought it up to 31.37%. :)

[quote name='Slugy']A great fraction, but it does have quite a lot of clipping of tanks, engines, and adaptors at the back: Isn't this against the rules?

I'm also curious as to how offsetting the tri adapters is regarded - it's clever but doesn't that fool the aero model into treating them all as attached to the bottom nodes?[/QUOTE]
The most objectionable clipping in this vessel to me is the LV-N into the LF tank, but it seems to be more of an aesthetic choice rather than an exploitative one so I'm allowing it. Clipping of structural parts I don't mind at all.

The tri-adapter offset is also acceptable to me. The front node of the adapter is still on the back of the Mk3 adapter, a better aero model would treat the same thing done with radial attachment points the same as this is treated.

I think of tewpie's entry as stretching the rules to their limit in search of better fractions, which is kinda what this challenge is about. :)

[tewpie]

[quote name='Slugy']The automated flight is very cool too, but it would be nice if it was flyable by human hands.[/QUOTE]

If by "human hands" you mean hands assisted with SAS and "hands on" autopilot ala smart a.s.s., then it is very possible to fly this plane, even achieve orbit with the same payload fraction if you time everything right.

If you mean naked controls, then no, probably not, but then neither are a lot of other entries and also real world spacecraft ;)

[Slugy]

[quote name='Red Iron Crown']Thanks for updating, this one is compliant and I've added it to the leaderboard. I calculated your fraction using KER's kg-accurate numbers, brought it up to 31.37%. :)


The most objectionable clipping in this vessel to me is the LV-N into the LF tank, but it seems to be more of an aesthetic choice rather than an exploitative one so I'm allowing it. Clipping of structural parts I don't mind at all.

The tri-adapter offset is also acceptable to me. The front node of the adapter is still on the back of the Mk3 adapter, a better aero model would treat the same thing done with radial attachment points the same as this is treated.

I think of tewpie's entry as stretching the rules to their limit in search of better fractions, which is kinda what this challenge is about. :)[/QUOTE]

The rear node offset is cunning, and opens some interesting possibilities.

The clipping of the LV-N is the one that I'd be most tempted by for aesthetics, they look silly hanging off space planes.

The clipping of most of the Rapiers into LF tanks seemed dodgy (it is very back heavy even with all the forward clipping) - time for a rule update?

[Red Iron Crown]

[quote name='Slugy']The clipping of most of the Rapiers into LF tanks seemed dodgy (it is very back heavy even with all the forward clipping) - time for a rule update?[/QUOTE]
Seems aesthetic to me. The tanks could easily be mounted further forward and the rapiers mounted conventionally without affecting mass distribution or performance significantly.

That said, it's clearly stated in the rules "In particular, do not clip engines at all." I guess this entry technically violates this rule, but seeing as it's aesthetic and not functional I'm inclined to let it slide.

[tewpie]

[quote name='Slugy']The clipping of most of the Rapiers into LF tanks seemed dodgy (it is very back heavy even with all the forward clipping) - time for a rule update?[/QUOTE]

There's other ways to maintain CoM balance without that sort of clipping, but they will make the plane uglier. I'm fine either way.

Edit: Just tried it, removing all clipping results in better handling and performance during takeoff (resulting in a slightly better payload fraction). The tradeoff is the plane is significantly more unstable during the landing phase, making autopilot landings a must, whereas currently, you can land it completely by hand.

If I'm not mistaken this is the exact same problem experienced by HOTOL (Skylon's predecessor) in the 1980s, due to the rear engine layout. Edited November 26, 2015 by tewpie

[Slugy]

[quote name='tewpie']If by "human hands" you mean hands assisted with SAS and "hands on" autopilot ala smart a.s.s., then it is very possible to fly this plane, even achieve orbit with the same payload fraction if you time everything right.

If you mean naked controls, then no, probably not, but then neither are a lot of other entries and also real world spacecraft ;)[/QUOTE]

I was thinking with just stock SAS and controls - but that is just my personal bias showing :)

It's an excellent result, with some interesting techniques.

The note about HOTOL suffering from CoP/CoM difficulties had passed me by - explains SKYLON's engine placement ...

[Val]

On ‎26‎-‎11‎-‎2015‎ ‎01‎:‎12‎:‎42, tewpie said:

Takeoff Mass: 274.17t
Payload Mass: 153.00t
Payload Fraction: 55.80%

Dammit, tewpie. I was planning to work on my new early career craft today.

Now I have to work on beating you again.

And I think I have my work cut out for me. Well done

I'm really impressed how you managed to squeeze 153 t into a single large cargo bay. I will probably have to study how you did that and do something similar.

Edited November 30, 2015 by Val
Fix migration formatting snafu

[Red Iron Crown]

OK, the OP needs some fixing up and I'm fairly busy helping with the forum migration, so I'll ask for some patience with me in reviewing/updating this.

[Nefrums]

The only parts that can survive being at the front off a ship that I have found are the heat shield and the shielded docking port.   Both of them have terrible drag, so much so that the difference of putting them in front of a size 1 stack and a size 3 stack (with adapters) are negligible.  This means that the drag of a large size 3 ship is not that much higher than a size 1 ship.

Have I missed something or are size 1 ships no longer viable for this challenge?

And why is it so hard to decouple wings without them smashing into the ship and wrecking everything...

[Val]

58 minutes ago, Nefrums said:

Have I missed something or are size 1 ships no longer viable for this challenge?

I tend to agree with this.

[Nefrums]

Sad but true, then.

I'm currently experimenting to see what gets the best performance of a shielded docking port or a small heat shield with a nosecone in front of it.   The heat shield have worse drag then the shielded docking port. The nosecone in front of it have significantly better drag, but will blow up and expose the heat shield around ~1300m/s.

 

[Nefrums]

I had to work hard to beet the reusable score with a non reusable plane.   But I think this design have a bit more to give.

Rhinoplane Mk1:

13 Rapiers, 6 Panthers and one Rhino!

Payload faction: 56.20%

 

 

 

[SpaceplaneAddict]

Holy crap.

[Nefrums]

This is the largest plane I ever built, it was fun.

I found a mod that allows me to unlock the fuel in tanks with action groups, This helped allot to get the rapiers to draw the fuel from the disposable tanks first.

Panthers are really good engines, they have better twr than rapiers at < Mach 2 and slightly better isp. But they flame out around Mach 3.

The 24dV that was left in the last stage means another 8-10t of payload should be possible with the same last stage.  Time to squeeze in a few more radial ore tanks in the cargo bay. 

 

 

Edited December 3, 2015 by Nefrums

[Nefrums]

And the Rhinoplane Mk2 gets: 57.16 %  

This time it has 15 Rapiers, 8 Panthers, 2 Nervs and the Rhino.

It had even more dV left this time.

I was a bit worried when the Rhino ran out of fuel when AP was at 42 km, but 6 min later the nukes had done their job and raised the AP out of the atmosphere. 

 

 

 

Edited December 3, 2015 by Nefrums