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Canopies for High-speed Ultra-Long Terrain Execution (CHUTE)

Description:

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Advanced Materials, Human-Machine Interfaces

 

OBJECTIVE: Design, develop and demonstrate a proof-of-concept ram-air parachute specifically capable of low-altitude (<1000 feet) and long-distance (>10 km) flight, in a parachute rig weighing <50 kg. Such parachute systems will need to be capable of forcing air into parachute cells to keep them inflated during flight over long distances, with ultimate range being a function of the capabilities of this forced air system. Proposers should include any testing capabilities needed to verify that the modified canopy is in an airworthy (jumpable) configuration, without significant impact to the probability of a successful opening.

 

DESCRIPTION: Parachute technology has evolved (Figure 1) since the creation of round canopies, which slow the rate of descent by creating drag. Ram-air canopies, developed in the 1970s, have inflatable parallel cells that fill with high-pressure air from vents that face forward on the leading edge of the airfoil. The fabric is shaped, and the parachute lines trimmed under load, such that the ballooning fabric inflates into a cambered airfoil shape. Air must flow faster over the top than the bottom, creating lift in addition to drag, and allowing steerability by controlled deflection of air. The use of airplane terminology is no accident; ram-air canopy designs share many features with airplane wings.

 

Figure 1. Evolution of parachute technology, demonstrating the steady growth toward rigid wing-like structures. CHUTE aims to redesign the canopy wing for long-distance, low-altitude flight with an airplane philosophy in mind.

 

In order to create a new paradigm for quiet, long-distance, low-altitude flight using parachutes, DARPA seeks to leverage recent advances in aerodynamics and materials technology to develop cost-effective ram-air parachutes that deliver a revolutionary leap in the distance that can be traversed, without significantly adding to the mass of the overall parachute rig or impacting its airworthiness (defined here as “jumpability”, the probability of a successful parachute opening). 

 

Today’s state of the art is dynamic, maneuverable cross-braced canopies used in the competitive high-speed sport of parachute swooping. Swooping canopies can generate speeds in excess of 70 miles per hour, traverse lengths greater than a football field at one foot above ground level (AGL), change direction abruptly when flying around “gates”, and land on a specific target with accuracy. Zero porosity aerodynamic parachute material, span-wise inflatable ribs, low drag lines, a more rigid wing-like design, and high wing loading allow finer control in close proximity to the ground, sometimes simply by shifting weight in the harness. However, modern parachutes ultimately remain a prisoner to energy conservation. Swoopers generate high kinetic energy by trading for potential energy (altitude over a drop zone). When this kinetic energy is exhausted, they must land, placing physics limits on speed and distance they can traverse.

 

Powered paragliders are one way that sustained flight may be possible. However, three limitations place constraints on the use of these systems for military operations: noise, weight and speed. Powered paragliders can create in excess of 120 dB of sound, typically weigh >250 lbs, and have large parafoils with dozens of cells, resulting in parasitic drag that limits sustained speed to <30 mph. Powered paragliders are therefore out of scope for this effort. The Joint Precision Aerial Descent System (JPADS) has used winches, wires and pulleys located below the parachute to demonstrate lightweight, adjustable airflow control on round parachutes, but is ultimately constrained by the round canopy’s limited maneuverability. Round canopies are therefore out of scope for this effort. Concepts that rely exclusively on powered cargo and do not add propulsion to the parachute canopy (e.g. LRPADS [2]) are out of scope. For more information on this topic, see https://www.youtube.com/watch?v=7_kqMjz94B8.

 

PHASE I: Phase I consists of a base period of six months that will result in the development, design, and refinement of a low-mass (<50 kg) parachute system design capable of long-distance (>10 km) flight, to create continuously inflated parachute cells at altitudes of 1000-3000 ft. AGL.

 

Successful proposals for this SBIR offering must make significant arguments supporting the ability to rapidly iterate and execute to meet the timelines laid out in this solicitation, while addressing three key aspects of the program goals: (1) how the method of powered propulsion or forced air will be integrated into the parachute wing and/or jumper; (2) to what degree such propulsion interacts with, or relies upon, ground effect aerodynamics and canopy wing design; (3) how the parachute and powered propulsion system will be built and tested via real-world jump operations planned for Phase II. Successful proposals will also demonstrate in-depth knowledge of aerodynamic design and parachute fabrication, and should illustrate how their method might be expected to meet the envisioned metrics.

 

This effort is expected to primarily center around new active airflow control and/or powered motor methods, that are conformally integrated with ram-air parachutes and allow sustained flight for as long as that control or power is provided. Methods such as adjustable inlet control, battery-powered bleed air for directional control, laminar flow injection, boundary layer control to maintain lift across long traverse distances, or other innovative methods, are suitable for investigation. Recent developments have shown that designed geometric openings can create macro-control with new wing shapes, or the opening/closing of slots or voids for air flow (e.g., ram air parachutes with controllable flaps for directional control). Additional efforts to minimize drag may be required to maximize range. 

 

Phase I fixed payable milestones for this program should include: 

Phase I Base period (required): 6 months

  • Month 2: Concept Design Review (CoDR) on powered parachute design, in accordance with the metrics below.
  • Month 4: Preliminary Design Review (PDR). Initial report on “do no harm” probability.
  • Month 6: Critical Design Review (CDR). Interim report on “do no harm” probability, scalability, proposed cost and noise estimates. Present initial test and evaluation plan, hardware purchase plan, and safety plan for Phase II testing. 

 

Performers may perform lab or bench-scale testing to increase design fidelity as desired, as long as this does not negatively impact the design review schedule. Performers will work with DARPA to identify potential transition partners for demonstrations in Phase II. Performers will present plans to manufacture prototype parachute(s) and test them in Phase II. 

 

Phase I metrics: Present the design, at a CDR level, of a parachute system that can:

  • Deliver air to canopy cells, or use other innovative methods, to maintain sustained parachute canopy flight at an altitude of >500 ft. AGL and <3000 ft. AGL (<5000 ft. MSL),
  • Do so for a horizontal flight distance greater than 10 km from the point of engagement,
  • Do so in less than 20 seconds from a manual initiation command,
  • Do so while preserving total mass of the parachute rig (to include a reserve parachute) at <50 kg,
  • If weight is added to the body of the jumper, add no more than 50 lbs. to the weight of the jumper,
  • Be capable of being engaged while airborne, and disengaged via manual control in order to land as needed,
  • Maintain a forward speed of at least 20 mph, at an altitude of >500 ft. AGL and <3000 ft. AGL (<5000 ft. MSL),
  • Determine the probability of a successful opening of the prototype, i.e., demonstrate “do no harm” with the added mechanism(s) to existing opening probability when in a rigger-approved, properly packed configuration.
  • Present estimates of the noise generated by the system in flight, in decibels (dB),
  • Present scalability calculations for maximum projected range, with added mass,
  • Present the proposed cost of the parachute system when produced at scale, as demonstrated via techno-economic analysis of the cost of production, in dollars per parachute rig.
  • Systems may use initiation energy from a parachute dive that increases velocity (e.g., a diving swoop that trades potential energy for kinetic energy), but may not use such methods when at the flight altitude.

 

Proposers must begin their effort with an experienced, licensed parachute rigger team, with significant practical experience in parachute packing, repair, evaluation, and modification. Additionally, by the end of Phase I, proposers should demonstrate the following: 

  • To show available expertise for Phase II fabrication of the proposed design: teaming with an existing commercial parachute manufacturer that has sold at least 5,000 airworthy canopy units; 
  • To conduct jump testing in Phase II: teaming with an existing US Parachute Association (USPA) compliant drop zone [1].

 

PHASE II: The Phase II effort consists of a base period of 12 months, an Option 1 period of 12 months and an Option 2 period of 12 months. The Option 2 period will follow the Option 1 period. DARPA reserves the right to release a separate Direct to Phase II (DP2) SBIR solicitation in lieu of exercising either Option.

 

Testing in the base period will center around design, feasibility testing and proof-of-concept. Experimental assessments of ram-air generation, and interaction with parachute cells, may also be necessary to demonstrate a proof of concept. Testing in the option periods will expand the maximum range, reduce noise, and conduct a challenge-based flyoff (Figure 2).

 

Phase II fixed payable milestones for this program should include: 

  • Base period: 12 months
    • Month 4: Bench Testing Review (BTR). First prototype ready for bench testing at parachute manufacturer facility. Deliver assessments of the degree of maneuverability and speed, and experimentally demonstrate key components that produce parachute cell inflation. Deliver interim report on trade studies, integration of hardware to canopy and canopy to rig, and system design. Present final test and evaluation plan, and safety plan for testing. 
    • Month 9 (optional; dummy real-world jumps may be substituted to achieve the same end goal): Complete wind tunnel testing. Deliver interim report, describing results of wind tunnel testing, design iterations, and manufacturing results. 
    • Month 12: Complete first round of dummy parachute jumps to evaluate airworthiness. Test Readiness Board (TRB) and Safety Review Board (SRB) to determine criteria for human jump testing, to include safety mitigation plans. Present readiness for live test to DARPA.  
  • Option 1 (Initial test jumps): 12 months
    • Month 16: Complete dummy parachute jumps to evaluate airworthiness. Go/no-go for human jump testing, to include updated safety mitigation plans. 
    • Month 22: Complete jump testing at USPA approved drop zone. Demonstrate steadily decreasing altitudes and steadily increasing ranges. Demonstrate at least 5 km. straight-line range at >500 ft. AGL and <2500 ft. AGL, in a parachute rig weighing <50 kg, and document real-world noise level (dB) in excess of the ambient.
    • Month 24: Update Phase II report documenting powered parachute system design and testing results, future specifications, manufacturing process, and evaluation of airworthiness. Evaluate cost of full-rate production using partner parachute manufacturer facilities.
  • Option 2 (Advanced test jumps): 12 months
    • Month 27: Demonstrate ability to perform ±50 feet of in-flight altitude adjustment by manual control. Demonstrate ability to interrupt/disengage the actuation system in order to land immediately. Test modifications to reduce sound level. Prepare expanded version of actuation system for long-range testing.
    • Month 30: Parachuting Challenge flyoff 1 (interim, home drop zone). Long-range (at least 8 km), low-altitude (maximum of 1500 ft. AGL) jump testing at USPA approved drop zone. 
    • Month 33: Parachute Challenge flyoff 2 (final, DARPA-selected drop zone). Maximum feasible range, low-altitude (maximum of 1000 ft. AGL) jump testing. Measure sound addition to the ambient noise level; validate <50 kg. total rig weight.
    • Month 36: Final Phase II report documenting powered parachute system design and testing results, manufacturing process, and verifications of airworthiness. Demonstrate long-distance, low-altitude system for Department of Defense observers and customers. Present future commercialization plans.

 

Figure 2. A notional Parachute Challenge flyoff course, demonstrating long-distance legs and steadily increasing sharpness of turns / smaller turn radius. The first challenge will occur at the performer’s partner drop zone. The second challenge will occur at a drop zone of DARPA’s choosing (SOA: state of the art).

 

PHASE III DUAL USE APPLICATIONS: Ram-air parachute technology is currently at high technology readiness level and in full-rate production for both military and civilian uses. Multiple commercial and DoD applications are envisioned after the successful demonstration of a powered parachute prototype.

  1. DoD use by Special Operations Command. The ability to use designed systems for silent, low-altitude ingress is expected to have significant ramifications for pararescue jumpers and military special operators. The ability to separate landing zones (LZ) from targets by over 10 km will allow significant freedom to ingress route planning, and place less demand on helicopter aircraft to place themselves in harm’s way to deliver operators to their LZs.
  2. Commercial use by US Parachute Association, and other international skydiving entities. Cross-braced canopies has created the sport of parachute swooping, which today boasts national and international championships, and the creation of over 20 distinct parachute designs, each of which has sold over 5,000 units at costs of >$4,000 USD per piece. A safe, powered parachute system is expected to revolutionize modern recreational skydiving and create a significant market for parachutes that can do more than simply land where the wind, and existing kinetic energy, dictate. The products delivered in this effort will create a new sport with significant mass-market attraction, and there is a viable business model from the skydiver audience – for example, the US Parachute Association alone has over 35,000 members.

 

REFERENCES:

  1. [1] USPA Dropzone Locator, United States Parachute Association. https://uspa.org/DZlocator
  2. [2] Long Range Precision Aerial Delivery System (LRPADS). https://ombra.us/product/long-range-precision-aerial-delivery-system/

 

KEYWORDS: Systems Level, Handling, Product Design, System

 

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