FAR Falcon Heavy Facsimile Breaks Under Atmospheric Stress

[macktruck6666]

Recently I have been fascinated by the work SpaceX has been doing.

I'm using Realism Overhaul with FAR

I think I'm pretty close to a realistic Falcon 9. Engine specifications, max payload, vehicle mass, and burn times are equal to released information. Fuel mass and fuel mix ratio are close to estimations on the web. It can get the max payload of 13,000 kgs to 125 km orbit.

The Falcon Heavy has some serious issues with FAR. the Falcon 9 has an approximate initial TWR of 1.2. The Falcon Heavy based directly on concept drawings has a TWR of 1.7. It quickly gets to 300 m/s and promptly explodes due to atmospheric stresses.

Falcon Heavy V2 came as a result of the Far problem. I added more fuel till the initial TWR was 1.2. This allowed me to get the max payload of 53,000 kgs to 125 km orbit.

So the question is: Is there some way to keep the size of the Falcon Heavy Boosters closer to the concept?

BTW, version 3 was a logical progression of the technology. With 6 boosters instead of the heavies 2 boosters. I was able to get 130 kgs to 125km orbit.

[cantab]

Straight from SpaceX's website at http://www.spacex.com/falcon-heavy

"Shortly after liftoff the center core engines are throttled down. After the side cores separate, the center core engines throttle back up to full thrust"

As well as reducing max Q, in the non-crossfeed setup this will increase delta-V. In KSP you could use the thrust limiters, but with a nine-engine cluster you might be better off setting action groups to shut down some of the engines.

[Red Iron Crown]

RO has an engine grouping tool installed by default, should be able to throttle down the center while keeping the boosters blazing.

(Love the Falcon Superheavy )

[macktruck6666]

I assigned the engines to groups, but I can't find the icon to control the throttle while I'm flying.

[Harry Rhodan]

There's also Throttle Limit Action Groups.

[macktruck6666]

Well, reducing the center engines to minimum thrust helped. I also realized that my version was 200 tons lighter then the concepts. The booster were to small so I made them bigger. Now the rocket shouldn't have problem with bare tanks, but the fairing is creating lift and breaking the rocket right under the fairing.

Edit: I used KOS to control the throttle.

[winged]

TWR of 1.7??? My version is 1460t with TWR of 1.23. Launch mass is based on SpaceX page: http://www.spacex.com/falcon-heavy

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[macktruck6666]

Ya, I got it down to around 1.29. BTW, I assume the mass spec doesn't include the payload? right?

Edited August 5, 2015 by macktruck6666