[0.14 stock] Bare Minimum

[Kosmo-not]

This is a one-way trip to orbit using the least amount of fuel possible: 1.5 tanks.

We\'ve known that 2 tanks + LFE was the bare minimum to get to orbit before the new release.

Now with the new half tank and small LFE, it\'s possible to get by with less.

This craft also demonstrates the benefit of good staging for larger rockets.

[togfox]

Are you sure that decoupler and engine is necessary? You\'d probably be even more efficient without it. The decoupler has a weight penalty that makes a ratio of one decoupler/engine per tank inefficient.

[Kosmo-not]

Are you sure that decoupler and engine is necessary? You\'d probably be even more efficient without it. The decoupler has a weight penalty that makes a ratio of one decoupler/engine per tank inefficient.

Yes, I\'m sure it\'s necessary. One can barely make it to orbit with 2 tanks and an LFE. Try doing it with 1.5 tanks. I don\'t think it\'s possible.

After passing 10km, the mass you are carrying with you starts to matter more than the thrust you have available. The big LFE weighs a lot when you consider a small rocket.

Think of it this way:

1 LFT = 2.5 mass

0.5 LFT + stack decoupler + small LFE = 2.55 mass

There is no noticeable difference between this rocket and the 2 tank rocket through the first tank of fuel. The delta-V capacity of the rockets for the rest of the flight are just about the same, but this rocket achieves this delta-V capacity with half as much fuel.

[togfox]

Oh - I\'m not doubting the amount of fuel needed. I\'m doubting the necessity of the decoupler and second engine. Dead weight. I shall try this myself and compare.

[UmbralRaptor]

This has almost 400 m/s more paper ?V than the 2-tank orbiter. I\'m guessing the similar mass ratios of each stage help?

@togfox Decoupler deadweight has nothing on engine (and before the fuel line patch SRB and tricoupler) weight. Also, while it\'s not obvious from the part sizes, the relative masses make this a decent example of staging. The portion of the ship above the decoupler is 2.75, while the part below is 4.5.

[sal_vager]

With the vectoring engine and careful flying I had more fuel left in orbit, but adding a chute was still just too much.

Perhaps if this craft were flown like the Goddard challenge rocket it\'d be possible to come back down safely.

[Kosmo-not]

With the vectoring engine and careful flying I had more fuel left in orbit, but adding a chute was still just too much.

Perhaps if this craft were flown like the Goddard challenge rocket it\'d be possible to come back down safely.

With its current engine, you do have to throttle down a little shortly after liftoff to get an optimal ascent.