Q A_Round_3_(3-14-13).pdf

DARPA-BAA-13-19

VTOL X-Plane

Questions and Answers – Round 3 14 March 2013

VTOL X-Plane BAA-13-19 Questions & Answers – Round 3

IN THE EVENT OF ANY INCONSISTENCY BETWEEN THE ANSWERS PROVIDED

HEREIN AND THE BAA, THE BAA SHALL TAKE PRECEDENCE

Q14. Are all of the funds listed ($47M, $130M) available for award (and GFE/GFP), or should we assume that Government resources for execution (e.g. oversight, travel, parallel analysis, other) must be covered within these amounts?

o A14. As the program is currently constructed, all of the funds listed are available for award (and GFE/GFP).

Q15. Is Lift/Drag (L/D) criteria required simultaneously with Vmax (300-400 knts) or is it a peak L/D (e.g. at Vbr)?

o A15. The criterion is a peak L/D for Vbr. The 300-400 kt speed requirement is a sustained cruise capability, however, and not just a short duration dash speed.

Q16. The BAA states, “Areas for the development and incorporation of innovative technologies include all aspects of … propulsion … structures, etc.” (p. 7) and “… innovative technical solutions include concepts for… hybrid designs… thrust augmentation … improved power loading … and integration (…mixed/heterogeneous systems)…” (p.8).

It also states, “The VTOL X-Plane program will not support the development of engines or new propulsion systems” (p. 9).

a. Does “no development” for “engines” refer to Gas Generator (High Pressure System) only?

b. Where is the line drawn on what is considered “hybrid design and configuration” versus

“not supporting new propulsion systems”?

c. Will modifications of low pressure propulsion system (fans, power turbines and concept specific propulsion ducting) fit criteria of “hybrid design and configurations”?

d. How much engine modification/integration will be permitted to demonstrate a “hybrid design”?

o A16. The intent of the guidance in the BAA is to inform the proposer community that this program cannot support an engine or power plant development effort. While it is understood that external (outside the core) adaptations of the engine may be part of the proposed design solutions, modifications to the engine core should not become the main or pacing elements of the program (gas turbines, turbo-shafts). Likewise, in the case of reciprocating engines or electric power concepts, the program cannot support the invention or development of new systems, although adapting existing systems is acceptable.

DARPA-BAA-13-19

VTOL X-Plane

Questions and Answers – Round 3 14 March 2013 o A16a. “no development” for engines refers to not making changes to the engine core, which includes the high pressure spool, the low pressure spool and the power turbine.

Modifications to the engine operating line are outside the scope of the present effort in the case of gas turbines and turbo-shaft engines. Similarly, developing new reciprocating engines or new electric motors, new power generating and/or new storage devices are outside the scope of the current effort.

o A16b. For hybrid propulsion configurations, all components such as power generators, motors, drives, power storage, etc. must currently exist in a usable form. The combination and adaptation of these into a new architecture or new configuration for providing power can be considered an acceptable modification.

o A16c. Modifications to the engine power core – including low-pressure fans, power turbines and internal ducting – are not acceptable. However, modifications to external ducting, external shafting or external power generation are acceptable.

o A16d. Internal engine modification is not supported as part of the current program.

Engine integrations into hybrid design architectures and new approaches to using existing engines and engine types are allowed.

Q17. The two factors in the system hover efficiency equation, “Thrust” and “Actual Power,” are not clear. Regarding thrust, it is inferred from the words in the BAA that download and system installation losses should be factored into the efficiency. In the BAA metric, using “thrust” (at the device) would not include these installation losses. Using GW would account for all system integration effects.

Is it intended to use GW, or should device thrust be used?

o A17. In the context of this BAA, for hover, “thrust” is defined as the total lift force necessary to sustain hover equilibrium.

Q18. The two factors in the system hover efficiency equation, “Thrust” and “Actual Power,” are not clear. The meaning of the term “Actual Power” is not clear, and so it is not clear whether or not it should include engine installation losses, transmission losses, accessory losses and/or anti-torque power. Does “Actual Power” refer to installed engine power output required to hover, an inferred uninstalled engine power, mast/shaft power at the thrust device, equivalent shaft power, or other. Please clarify.

o A18. “Actual Power” refers to the installed engine power output required to hover. It therefore includes all sources of power consumed by the aircraft in a given flight state.