# The Alpha Delta Challenge

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Hello guys.

Today, I am presenting a new challenge.

The Alpha Delta Challenge.

I see spaceships with huge amounts of delta-V, but with 4 hour long burns just to escape orbit.

I find that ridiculous. So. I have a new challenge to present.

Come up with the ship with the highest Delta-V with the Highest TWR you can obtain. Your score will be:

Delta-V * TWR ^ 1/4

Enjoy guys. A screenshot must be taken with the ship IN ORBIT with Kerbal engineer telling you how much delta-V you have and how much TWR along with ISP Also, have your apoapsis height and periapsis height on the screen too so I can confirm you're in orbit.

Weight Classes:

Below 5 tons:

Below 20 tons:

Below 50 tons:

Below 200 tons:

αΔ  = 38988 @Teilnehmer

Unlimited:

1st:

Edited by NicholaiRen

Will doo...

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Great challenge!

My suggestion is to introduce weight classes, e.g.:

• Below 1 ton
• Below 3 tons
• Below 10 tons
• Below 30 tons
• Below 100 tons
• Below 300 tons
• Unlimited
Edited by Teilnehmer
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5 hours ago, Teilnehmer said:

Great challenge!

My suggestion is to introduce weight classes, e.g.:

• Below 1 ton
• Below 3 tons
• Below 10 tons
• Below 30 tons
• Below 100 tons
• Below 300 tons
• Unlimited

Sure. But I think 1 ton is a bit unrealistic.

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Gonna work on this one. Soon. This weekend maybe. I haz tests

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@NicholaiRen I don't think that your ranking system is so good. This very simple rocket has a score of 8.72 * 2224 = 19,393.28.

And this one has scored 2,134 * 14.8 = 31,583.2.

If these rockets have scored more than ten times your mothership.....

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2 minutes ago, CairoJack said:

@NicholaiRen I don't think that your ranking system is so good. This very simple rocket has a score of 8.72 * 2224 = 19,393.28.

And this one has scored 2,134 * 14.8 = 31,583.2.

If these rockets have scored more than ten times your mothership.....

That's a good point..........

What's the ISP of those rockets?

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1 minute ago, NicholaiRen said:

What's the ISP of those rockets?

315

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2 minutes ago, CairoJack said:

315

Eh, that wouldn't be a fair representation either.

Mine has 800. Which would mean it beat yours, but can still be cheated.

How should I score this?

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Maybe ∆v * TWR^(1/4). With this scoring system your mothership beat my rockets.

Edited by CairoJack
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46 minutes ago, CairoJack said:

Maybe ∆v * TWR^(1/4). With this scoring system your mothership beat my rockets.

Seems good to me.

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I’ve done some calculations.

For single-stage vessels, the best αΔ (= TWR ∙ Δv) value is achieved when the total mass of engines equals a certain fraction of the total vessel mass, namely,

mengines = mwet ∙ (ete^(W(et) − 1) / (t − 1)),
where
W is the Lambert function,
t is the tank ratio, i.e. the ratio between the dry tank mass and the wet tank mass.

For t = 1/9 (most LfO and Lf tanks), mengines = 0.40055 mwet

The value of αΔ is directly proportional to engine’s thrust and Isp and inversely proportional to engine’s mass. It does not depend on the engine count.

The optimal engine would be the Twin-Boar if it wasn’t combined with such a large fuel tank.
The actual optimal engine appeared to be the Mammoth with the optimal fuel amount of 20 t per engine.

So, @CairoJack’s second entry seems actually to be the best among single-stage solutions!

Not sure yet about multi-stage ones.

BTW, one should use the TWR (surface) value instead of the local TWR as the latter depends on the altitude and thus is inconvenient for comparison.

Edited by Teilnehmer
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Multi-stage vessel with Δv = 4117 m/s. TWR (surface) never drops below 9.47.

αΔ  = 38988

Edited by Teilnehmer
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4 minutes ago, Teilnehmer said:

Multi-stage vessel with Δv = 4117 m/s. TWR (surface) never drops below 94.7.

αΔ  = 38988

Congratulations.

How did you get a perfect 100,000 orbit? RCS thrusters?

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1 hour ago, NicholaiRen said:

How did you get a perfect 100,000 orbit? RCS thrusters?

Hyperedit

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On ‎2017‎-‎10‎-‎18 at 5:23 AM, Teilnehmer said:

Hyperedit

Lol XD

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On 10/18/2017 at 1:46 AM, Teilnehmer said:

So, @CairoJack’s second entry seems actually to be the best among single-stage solutions!

Wow. I did that ship in ten seconds!

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I'd take part in this challenge if the "weight category" was based on launch mass,  because then there is some scope to get crafty and try combine something with high twr/delta v in orbit whilst keeping launch mass within your weight class.

On the other hand, if you are able to use Hyperedit/Set Orbit and the weight categories are based around the weight in orbit,  there doesn't seem all that much too this -  cluster as many Mammoths around a mk1 lander can as possible, with enough fuel to make your weight category?

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