Effect of Larger Fairing on Performance

[heavylift]

Hey all,

Does anyone have a good sense of the effect of a larger fairing (for vehicles that may not be mass constrained but are volume constrained for payloads) on the net payload capacity, all other things constant?

I've been having a hard time finding a good example of a launcher that has had both a "same diameter as stage" fairing, as well as a "larger diameter than stage" fairing, all on the same stage, such that the comparison can be made.

Obviously the exact mass, design, etc all matter, but I'm curious on a first-order level what percentage hit you may get from that sort of decision.

Anyone know an answer, or if not, then at least good examples of launchers that have both a Df = Ds (Diameter of fairing = diameter of stage) and a Df > Ds configuration?

[edkyle99]

One example was (is?) Minotaur-C (Taurus).  The Taurus 3110 model had a 1.6 x 4 meter fairing and could lift 1.054 tonnes to 400 km x 98 degrees.  Taurus 3210 with a 2.34 x 6 meter fairing could boost 0.882 tonnes to the same orbit. 

 - Ed Kyle

[dondar]

One example was (is?) Minotaur-C (Taurus).  The Taurus 3110 model had a 1.6 x 4 meter fairing and could lift 1.054 tonnes to 400 km x 98 degrees.  Taurus 3210 with a 2.34 x 6 meter fairing could boost 0.882 tonnes to the same orbit. 

 - Ed Kyle

and the difference can be explained by the weight difference. It should be around ~ tone.

[heavylift]

One example was (is?) Minotaur-C (Taurus).  The Taurus 3110 model had a 1.6 x 4 meter fairing and could lift 1.054 tonnes to 400 km x 98 degrees.  Taurus 3210 with a 2.34 x 6 meter fairing could boost 0.882 tonnes to the same orbit. 

 - Ed Kyle

and the difference can be explained by the weight difference. It should be around ~ tone.

The mass effect makes sense -- but I was imagining there was a non-negligible effect due to the aerodynamics of a boattail as well.

Would you say you consider that negligible compared to mass effect?

[ccdengr]

The mass effect makes sense -- but I was imagining there was a non-negligible effect due to the aerodynamics of a boattail as well.

If it mattered that much, one imagines there would be less use of hammerhead fairings.

There's more concern from transonic buffeting than pure drag, see "Simulation of a Hammerhead Payload Fairing in the
Transonic Regime", https://www.nas.nasa.gov/assets/pdf/staff/Murman_S_AIAA_2016_1548.pdf

[Jim]

Launch vehicles are not as concerned about drag as aircraft.  Look at an Atlas V metallic fairing or Delta II SRM attach fittings.
Delta II 10 foot metallic fairings didn't even have a boat tail.

There is a short term effect from the larger planform but weight is there the whole time.

[Hog]

Launch vehicles are not as concerned about drag as aircraft.  Look at an Atlas V metallic fairing or Delta II SRM attach fittings.
Delta II 10 foot metallic fairings didn't even have a boat tail.

There is a short term effect from the larger planform but weight is there the whole time.

Does the short term include acceleration while in the atmosphere, or even shorter term such as right around max Q?