Latitude has developed a new concept for long endurance Vertical Takeoff and Landing. Utilizing the Cloud Cap Technology’s Piccolo Autopilot we have enabled a role-expanding capability for unmanned systems.
The Hybrid Quadrotor offers a logistically simple solution to the problem of vertical takeoff and landing.
The Hybrid Quadrotor (HQ) is an innovative airframe technology that the combines the vertical takeoff and landing (VTOL) capabilities of a quadrotor and the efficiency, speed, and range of a normal fixed-wing aircraft.
The HQ offers significant advantages of existing “runway independent” unmanned air systems, including:
- Reduced operational footprint – no runway requirement, no approach obstacle issues, no launch/recovery infrastructure required.
- Portability – by eliminating launch and recovery equipment, there are significantly less items to transport and ship.
- Lower initial system cost – no launch and recovery infrastructure or expensive aircraft sensors required for VTOL capability.
- Reduced ongoing operational costs – fewer complex and cumbersome system elements to maintain, fewer people required to operate the system.
What is it?
Hybrid Quadrotor (HQ) is a technology that enables Vertical Take Off and Landing (VTOL) capability in fixed wing aircraft. It uses electric propulsion for the takeoff and landing phases of flight, and a gas-powered engine for the fixed wing phase.
Latitude Engineering, LLC. developed the control method and has implemented it on the Piccolo autopilot.
Why is it better?
HQ gives VTOL aircraft better endurance than a helicopter or multi-rotor and a smaller logistics footprint than a fixed wing aircraft. It lets fixed wing aircraft operate from areas they wouldn’t otherwise be able to.
How long can it hover?
The VTOL system is intended only for launch and recovery. It is not intended to hover for large fractions of the total flight time. While “hover and stare” type of uses are not appropriate, uses which require a few launch/recovery cycles can be done. Examples of missions that suit HQ include: delivering medical supplies to remote areas, placing sensors on ice, or picking up samples from a collection team in the field.
Why would I use one?
• Compared to a helicopter, HQ is simpler, cheaper, more reliable, and has better endurance.
• Compared to a pure multirotor, HQ has better endurance, better wind resistance, higher top speed, and can cover more ground.
• Compared to a conventional fixed wing aircraft, HQ technology can operate from more places for less cost.
Can it fly in the wind?
Yes, in fact a certain amount of wind makes operations easier. Latitude has demonstrated multiple launches and recoveries in winds over 15 knots. On one launch, we recorded a maximum wind of 20 knots. We believe that operations in winds greater than 30 knot are achievable.
Can it land on a ship?
We’re working on this. We believe this is an excellent use case for HQ technology, as it doesn’t require large equipment which fouls the deck of a ship.
Why not use a helicopter?
If hovering for large portions of the flight is your mission, then a helicopter may be a better option. If long duration hover is not vital, HQ technology far outperforms helicopters for endurance, range, and cost. In addition, there’s less vibration (makes for nicer pictures) and less components to break.
Why not use a multi-rotor?
If you only need to fly for 20 or 30 minutes, then a multirotor may be just fine. On the other hand, HQ gives multirotor VTOL capability but with longer endurance, higher speeds, and better wind performance.
Why not use a regular airplane?
If you need maximum possible endurance, and you don’t mind the constraints of a runway or launcher and net, then a standard fixed wing aircraft is the way to go. However, even with launchers and nets the airplane needs a clear path to take off and land. The advantage with HQ is now every parking lot, pier, forest clearing, and rooftop is a suitable launch pad. HQ allows you to launch and recover right where you need to work. Setup is easier without a launcher or net. If you’re operating from a ship, fouling the deck is a problem – HQ solves that. In addition, the aircraft scales well; we have notional designs over 1000lbs gross weight. You don’t want to catch an airplane like that in a net.
What about a tail-sitter?
Several VTOL concepts have used a tail-sitting approach, where the aircraft rotates vertical and hovers, using the main propeller as the VTOL thrust device. There are three main problems with this approach:
First, the aircraft’s wing is vertical. In this position, it does no good in helping lift the aircraft, and it gets blown around by winds. By keeping the wing level, HQ minimizes the disturbance caused by winds over the wing, and when hovering in headwinds, the wing actually helps lift the aircraft.
Second, the main engine must be sized for the VTOL portion of flight. Often, the power required dictates the use of a powerful and light two-stroke engine. These engines can use twice the fuel as a four-stroke for the same power, seriously reducing endurance. Regardless of the engine type, it is required to be much larger than necessary for forward flight, so you’re still carrying around a whole lot of unused engine. HQ uses a dedicated VTOL system which is optimized for
Lastly, the single propeller must do both the VTOL and fixed wing jobs, and it won’t be optimized for either. A non-optimal prop for the VTOL portion of flight will further increase the power requirements and increase the required size of the single engine.
Why not a tilt-rotor?
Tilt-rotors address the forward speed limits inherent in the design of helicopters. In exchange for a higher top speed and more range, there is a loss of payload capacity and a large increase in complexity and cost. In the case of the V-22 Osprey, its military mission justifies the cost. In smaller UAS use cases, and especially those needing cost-effective, low-maintenance solutions, HQ will deliver equal performance at lower cost.
HQ technology is simple and has few moving parts.
How can I get one?
HQ technology is available in several ways:
• Latitude is developing an entry level aircraft. It will have approximately two pounds of payload and stay aloft for five hours.
• Arcturus UAV offers the Jump 15, a derivative of their venerable T-15 aircraft.
• HQ is a licensed feature capability for the Piccolo autopilot, from Cloud Cap Technology. Anyone (subject to export rules) can purchase a Piccolo and an HQ license and implement their own hardware. HQ technology is covered under one or more patents pending.
Can I add HQ to my aircraft?
Yes! Latitude has converted existing fixed wing aircraft to VTOL enabled vehicles, as has Arcturus UAV.
Can I build my own?
Yes! HQ capability is a licensed feature of the Piccolo autopilot. An integrator would purchase a Piccolo system from Cloud Cap Technology, and an HQ license from Latitude Engineering.
We can assist airframe manufactures in designing their systems.
Does it work with [insert UAV accessory here]?
HQ is implemented on Cloud Cap Technology’s Piccolo autopilot. Any system which interfaces with the Piccolo is also compatible with HQ. A large ecosystem of payloads, engines, radios and other items required to get the job done are available.
Is it hard to use? Do I need to know how to fly a helicopter?
No. HQ technology is autonomous, from launch to recovery. Operators familiar with the Piccolo autopilot and Piccolo Command Center will find cross-training easy.
How much does it cost?
In terms of performance, HQ is a trade, just like all engineering decisions. For maximizing endurance or range in a VTOL platform, HQ is the best option we’ve seen.
• As a rule of thumb, the hardware required to implement an HQ system requires about 15% of the vehicle’s gross weight. Not bad considering you’re taking your runway with you!
• Landing gear can be simplified, eliminated, or replaced with skids.
• Structural requirements for launch and recovery loads are less than for a launcher/net system.
• Drag is increased; the impact depends on the aircraft’s mission requirements. At lower speeds, the drag penalty is minimal. If loiter time is your goal, then flying a little slower can make up the difference in endurance. If speed or range is your goal, you can reduce wing area and take advantage of the fact that you no longer need a low stall speed to accommodate the launch and recovery method. To quote Doc Brown, “Where we’re going we don’t need roads” (or runways or launchers or nets).
How much does it cost, in dollars?
In terms of dollars, in most cases, total system cost savings are achieved by using HQ technology. Some considerations, when considering a comparison to an equivalent fixed wing aircraft:
• Launchers and nets are immediately eliminated, saving the cost of acquiring, maintaining, setting up, and transporting these large pieces of equipment.
• Fixed wing systems which autonomously launch and recover typically require a precision landing position source, usually dGPS or our laser altimeter. The test flights to date have all been accomplished with only standard WAAS enabled GPS.
• Piccolo systems with HQ capability start at $8,500.
Contact us for a quote for the Piccolo II, Piccolo SL, or Piccolo Nano.
What about FAA regulations?
Currently, the Federal Aviation Administration requires a COA or experimental certificate to fly any UAS in unrestricted airspace for non-hobby use. When the FAA releases regulations allowing commercial use, we expect that small aircraft will be required to have ground based observers. HQ technology will give users greater flexibility in launch locations, eliminating chains of observers required to get from a suitable launch and recovery site to the location the work is actually being performed.
How About Safety?
All aircraft deserve respect and care in their operation, especially as they grow in size and capability. Latitude has implemented numerous safety features, including:
• Independent operator software lock on VTOL motors.
• Pilot-in-the-loop launch command (an optional setting) allows the pilot to have the final say on the launch command and helps prevents operator mistakes from triggering unwanted VTOL power.
• Safe mode logic prevents unwanted starting of the VTOL motors caused by unanticipated states.