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QR-31 — aerial view
QR-31 — detail view 1
QR-31 — detail view 2
Multirotor Inquiry Only
QR-31
3.5" Indoor Reconnaissance & Training Airframe
Prop Class
3.5"
Motors
1804 2450KV
FPV
Analog · 19×19
Flight Time
8–12 min
Battery
850–1400mAh
Origin
NC, USA

A compact 3.5" multirotor airframe purpose-designed for interior reconnaissance, confined-space navigation, and pilot training — where size, maneuverability, and low risk of collateral damage matter more than endurance. Set up for analog FPV with a 19×19mm camera and built around durable PA612-CF nylon. The kit ships ready to install electronics: all heat inserts are pre-installed and every bolt needed for assembly is included. Battery, battery strap, and FPV electronics are not included.

Not available for online purchase · Contact us for agency availability
Platform Details
Ships ready to install electronics · Assembly hardware included
Free ShippingOn every order
Fast ShippingQuick dispatch
USA DesignedNorth Carolina
Launch AlertsBe first to know
Ready to BuildHardware included
Product Supportsupport@sentineldynamicsllc.com

The Sentinel Dynamics QR-31 is a compact 3.5" multirotor airframe built for the spaces most platforms can't operate in. Purpose-designed for interior reconnaissance, confined-space navigation, and pilot training, it prioritizes size, maneuverability, and low risk of collateral damage over endurance. The kit ships ready to install electronics — set up for analog FPV with a 19×19mm camera. The QR-31 is not sold through the online store. Contact us for agency availability.

Design Intent

  • 3.5" prop class and compact frame geometry for doorways, hallways, and confined structures
  • Set up for analog FPV with a 19×19mm camera
  • Comes ready to install electronics — all heat inserts are pre-installed
  • Every bolt needed for assembly is included
  • Durable PA612-CF nylon construction prioritizing structural rigidity

Who This Is For

  • Operators who need an interior reconnaissance and confined-space platform
  • CQB and indoor recon use cases where size and low collateral risk matter most
  • Training programs needing a low-consequence, fast-turnaround trainer
  • Builders who want a compact, durable airframe that's ready to build

Power & Flight

  • Battery capacity: 850–1400mAh — battery and strap not included
  • Flight time: 8–12 minutes per pack
  • Analog FPV system with a 19×19mm camera

The QR-31 arrives with all heat inserts installed and the hardware needed for assembly in the box — drop in your electronics and fly. The default configuration is built around a 20×20 AIO flight controller, mini-style VTX, 1804 2450KV motors, a 19×19 analog FPV camera, and an ELRS / Crossfire receiver and antenna.

Agency Availability
The QR-31 is not sold through the online store. Contact us to discuss availability for your agency or training program.
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Platform Overview
Learn more about the QR-31 platform — its mission profile, capabilities, and where it fits in the Sentinel Dynamics lineup.
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Replacement Parts
Platform-specific replacement components for the QR-31 will be available alongside the full platform release.
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SpecificationValue
Airframe
Platform Class3.5" Multirotor (Quadcopter)
Prop Class3.5 inch
Build MethodFDM Additive Manufacturing
Design OriginNorth Carolina, USA
ArchitectureCompact, frame-kit construction
Mission Profile
Primary RoleInterior reconnaissance & confined-space navigation
Secondary RolePilot training / high-repetition flight
RangeShort range
FC FirmwareBetaflight, Ardupilot
FPV & Electronics
FPV SystemAnalog
Camera19×19mm Analog FPV
Flight Controller20×20 AIO (default configuration)
VTXMini-style VTX (default configuration)
Motors1804 2450KV (default configuration)
ReceiverELRS / Crossfire — receiver & antenna
Power & Flight
Battery Capacity850–1400mAh
Flight Time8–12 minutes
Battery StrapNot included
In the Box
Heat InsertsPre-installed
Assembly HardwareAll bolts for assembly included
ElectronicsReady to install (not included)
Materials
FramePA612-CF Nylon
Availability
StatusNot sold online. Contact us for agency availability.
ComponentDefault ConfigurationNotes
Flight Controller20×20 AIOAll-in-one stack, 20×20mm mounting
VTXMini-style VTXAnalog video transmitter
Motors1804 2450KV4× — sized for the 3.5" prop class
Camera19×19 Analog FPV CameraAnalog FPV system
ReceiverELRS / CrossfireReceiver & antenna
Battery850–1400mAh LiPoBattery & strap not included · 8–12 min flight
FramePA612-CF NylonHeat inserts pre-installed · assembly hardware included
⚠ Ready to Install Electronics The QR-31 ships with all heat inserts pre-installed and the bolts needed for assembly included — set up for analog FPV with a 19×19mm camera. Electronics are not included. The configuration above is the recommended default; final specifications will be confirmed at launch. Join the waitlist for the complete build guide.
Why QR-31

Built for the Spaces Others Can't Reach

01
Interior Operations
3.5" prop class and compact frame geometry allow navigation through doorways, hallways, and confined structures where full-size platforms are impractical.
02
Compact Payload Bay
Sized to carry lightweight FPV and reconnaissance cameras for interior operations, with accessible mounting and no structural modification to the airframe.
03
Purpose-Built for Training
Low kinetic energy and compact geometry make it ideal for pilot training — high repetition, low consequence, and fast turnaround between flights.
04
Open Integration
Compatible with Betaflight and Ardupilot, printed in durable PA612-CF nylon for a resilient, field-serviceable airframe.
Sentinel Dynamics
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QR-31
Join the Waitlist

The QR-31 is coming soon. Be the first to know when it launches — we'll send you a direct notification as soon as it's available, along with pricing.

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