SSI: Viper Class Shuttlecraft -- VTOL SSTO

[Cruzan]

Here's the latest shuttle I've designed for SSI, The Viper!

It's a Type 2 Shuttlecraft meaning it's a 2-seater VTOL SSTO and capable of completing SSI certification with ease. The Viper is very maneuverable and easy to fly!

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Contents

Craft Info

Engine Info

Flight Profile/Details

Re-entry and VTOL Help

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Craft Info

Part count: 81

Mass: 10.48 tons (Full), 8.68 tons (Empty)

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Engines

VTOL: 1 Basic Jet Engine

Atmospheric Flight: 1 TurboJet Engine

Space: 2 Rockomax 48-7S Engines

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Flight Details

Action groups:

1. Toggle Rockomax Engines

2. Toggle TurboJet Engine

3. Toggle VTOL Engine

4. Toggle Ladder

0. Toggle Intakes

Pre-Launch

Turn on SAS, Press 0 (Zero key) to toggle off excess intakes, Press 3 to turn on VTOL Engine, Throttle up to full.

Take-off

The Viper is slightly tail-heavy when fully fueled (intentional ) so it will pull back initially on take-off. You can choose to either pitch forward slightly once it lifts off, or directly engage you TurboJets by pressing 2. I prefer the latter as it makes for a very quick take-off profile.

Initial Climb: 0 to 10km

There's a thousand ways you can climb, but I'll just provide one. Once you've toggled on your TurboJets, stay pitched at or below 10 degrees until you build up to a velocity of about 60m/s. Next, Pitch up to 45 degrees until your velocity is about 110m/s. At this point Press 3 to Toggle off the VTOL Engine. Pitch up to 65 degrees or above right away. Begin climbing.

First Pitch adjustments: 10km to 25km

Once you hit 10km Press 0 (Zero) to toggle on all your air intakes. Continue climbing at 65 degrees until 13km. Pitch down to 45 degrees and continue climbing.

At 19km pitch down to 25 degrees.

At 25km, pitch down to 5-10 degrees

Gaining speed! 25 to 33km

You can keep the Viper pointed at 5-10 degrees, just make sure you vertical velocity (gauge on the top-middle of your screen) stays at, or just under 100m/s. We still have a ways to climb before we worry about flaming out. Control this by keeping your pitch in the 5-10 degree region.

At 32km you should still be climbing at 100m/s and ideally will be reaching 2000m/s Surface Velocity. Pitch down to 0-5 degrees to bring your vertical velocity closer to 10m/s on the gauge. This is the money zone!

The Flame-out Dance: 33km to 50km

Keep your nose pointed at about 0-5 degrees.

At 33km you're approaching your first flameout threshold (34km) so begin throttling back. Start with going down 2 notches at 33.5km.

At 34.5km you should be nearing half-throttle.

At 36.5km you should be closer to 1/3rd throttle.

At 38.5km you'll be just under 1/3rd throttle.

At 41km you should about 2 notches from no throttle. I usually pitch up to about 15 degrees at this point.

At 50km You should be juuust under the last notch of throttle. Check your map and look at your Apoapsis. You should have an apoapsis well over 75km if you've done everything right. Feel free to milk the jets a little longer if you want.

Circularize: @Apoapsis

Standard stuff here. Toggle off your TurboJet by pressing 2, Turn on your rockomax engines by pressing 1. Fire away! You should have about half of your liquid fuel left at this point if everything has gone well.

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Re-entry and Landing Notes

Re-entry

The Viper is very stable on re-entry. Turn off your air intakes by pressing 0 to reduce drag. Keep your nose pointed within 5-10 degrees of your prograde marker and you'll be fine.

Flying VTOL

Without doing a full tutorial on flying a VTOL Jet, here are the basics that are specific to this craft:

Breaking points for lift-off from ground is just under 10 notches, or 2/3rds throttle.

How to use this info: Basically this is the point on the throttle you'll use to land. When landing, you shouldn't ever need to go more than 1-2 notches above/below this point as it will cause rapid changes in elevation. The ship responds relatively quickly to throttle adjustments. Mess around with it and you'll get the hang of it if you aren't used to VTOL landings.

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Craft File

Mediafire: SSI Viper Class

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Enjoy!

Thanks for checking out the Viper. Hopefully you download it and get a chance to fly it. If you do please let me know what you think. I'm looking for any tips/advice on making it better, so don't be shy. If you've got any feedback to give it would be greatly appreciated!

Be sure to check out SSI's General Catalog for more awesome shuttles/SSTO's!

Edited October 8, 2013 by Cruzan

[BostLabs]

Interesting craft. I will have to check it out.

[Simplicity]

Looks very interesting, gonna have to give this one a go - thank you....

[inigma]

posted to the SSI General Catalog. Thanks Cruzan. Awesome ship!

[Cruzan]

Awesome! Let me know what you guys think if you get a chance to fly it.

[Elmetian]

Awesome! Let me know what you guys think if you get a chance to fly it.

Thought I'd give your bird a whirl in return

First attempt went very smoothly. The Viper airhogs nicely, and after following your instructions I can say they're even a little conservative. I pushed my apoapsis to 79km without much trouble (think I flamed out briefly at 48km altitude). She's a little twitchy at lower altitudes and takes a while to get up to speed, but that's to be expected for a small one-engined craft. Otherwise, she's pretty solid from 10km upwards. RCS seems nicely ballanced as well. I took her to meet some of my other craft at my Orpheus refuelling station:

[Rune]

It is indeed nice. Amazing that you have packed those aesthetics in such little package!

Rune. It's hard to keep up with the quality increase lately. That's a good thing

[Cruzan]

Thought I'd give your bird a whirl in return

First attempt went very smoothly. The Viper airhogs nicely, and after following your instructions I can say they're even a little conservative. I pushed my apoapsis to 79km without much trouble (think I flamed out briefly at 48km altitude). She's a little twitchy at lower altitudes and takes a while to get up to speed, but that's to be expected for a small one-engined craft. Otherwise, she's pretty solid from 10km upwards. RCS seems nicely ballanced as well. I took her to meet some of my other craft at my Orpheus refuelling station:

Thanks for the feedback. Ya I wrote out that flight profile by finding altitudes that I flamed out at, then knocking off 500-1000m less than that for the posted profile to make sure people wouldn't flameout. If you push it right to the flameout point you can definitely get a better ascent . I debated putting another jet on her tbh, but I figured it would need a little more jet fuel to compensate. Maybe the next model will have more speed!

Those pics are sweet Whats that little ship on the bottom left of this pic? I see you've got the Sanzuwu in there!

It is indeed nice. Amazing that you have packed those aesthetics in such little package!

Rune. It's hard to keep up with the quality increase lately. That's a good thing

Aesthetics? All those backward facing nosecones on the top are vital components to the ships performance!

Hehe thanks for the compliments Rune!

[Elmetian]

Those pics are sweet Whats that little ship on the bottom left of this pic? I see you've got the Sanzuwu in there!

Thanks That little one is the extended version of my Caged Canary. I had to undock it to make room for the Viper. Think I need to add more docking ports on my next orbital refuelling station!