Open-flow wind tunnel technology
TT JetFly — open-flow training for defence and tactical units
An open-flow wind tunnel engineered for group freefall training — up to eight flyers at once — without the building a recirculating tunnel needs.
TT JetFly draws air straight through a 4.8 m flight chamber instead of recirculating it around an enclosed loop, cutting the civil-works cost and footprint a defence training programme has to fund.
Why open-flow
A recirculating tunnel needs a building around it. An open-flow tunnel doesn't.
A recirculating wind tunnel — TunnelTech's TT-PRO line among them — moves air around a closed loop, which means the loop itself has to be enclosed: a return duct, climate control, and a building sized to contain all of it. That enclosure is a large share of a project's civil cost, and on a base or training compound it's often the part that takes longest to approve and build.
TT JetFly draws air straight through instead: in through one bellmouth, up through a 4.8 m flight chamber, and out through the other. Nothing recirculates, so there's no return duct and no building to construct around it — just the tunnel structure itself, an access tower, and a foundation.
Open-flow (non-recirculating) configuration
Sized for team formation-skydiving training, not solo flight.
Chamber capacity for a full formation-skydiving team, per TunnelTech's JetFly engineering concept.
Two concept elevations from the JetFly engineering study
Renderings from TunnelTech's open-flow concept work, shown here as engineering studies rather than a built installation.
Concept renderings only. Final geometry, materials and colour scheme are established during project engineering.
Core technology
Straight-through airflow, built around group training
The same engineering discipline behind TunnelTech's recirculating TT-PRO tunnels — fan selection, duct design, glass engineering — applies to the open-flow configuration; only the circuit topology changes.
The market today
Open-flow tunnels are an established category — and one incumbent leads it
Open-flow and open-air wind tunnels for military and tactical training are not a new idea. Aerodium Technologies, a manufacturer with roots going back to 1979, has built more than 100 projects in 46 countries and has worked with military customers for over 15 years; its published open-air line runs from a two-flyer Mobile model to an eight-flyer PRO configuration with a 3.55 × 6.5 m flight area.
TunnelTech's position in defence training so far has been the recirculating side of the market: TT-PRO tunnels delivered to named armed-forces and government customers below. JetFly extends that same engineering team into the open-flow category, for customers who want it from the manufacturer already trusted with their recirculating programme rather than a second vendor relationship.
Across 46 countries, per Aerodium's published figures.
3.55 × 6.5 m flight area, published pricing from €3.9M (franchise terms).
7.2 m chamber height, up to 8 flyers.
Named armed-forces, police and government customers on our recirculating TT-PRO line.
Aerodium figures are drawn from aerodium.technology, current as of August 2026. TunnelTech references are as published in our military freefall training coverage; JetFly-specific installations are not yet public.
TunnelTech + EVG Lufttechnik
The same fan and duct engineering, whether the circuit closes or not
TunnelTech is a shareholder in EVG Lufttechnik GmbH, our long-standing strategic partner. EVG has worked in industrial fan engineering since 1977 and has manufactured axial fans since 1987.
JetFly's intake and exhaust ducting is engineered by the same team and to the same standards as the closed-loop ducting in our TT-PRO tunnels — the circuit topology changes, the engineering discipline doesn't.
What a defence-grade facility has to provide
Military and police training carries requirements a leisure tunnel doesn't
Detailed PRO-series and JetFly specifications for identified defence customers go beyond a published spec sheet. These are the requirements that shape every proposal.
Real manufacturing. Real project sites.
The same production line as our recirculating tunnels
Actual manufacturing and installation work from TunnelTech projects — JetFly's fans, ducting and glass come off the same production line as our TT-PRO tunnels.
Single-point project responsibility
From programme requirement to an operational facility
- 1
Requirements & site analysis
Student throughput, equipment loads, group sizes and site constraints.
- 2
Aerodynamic & structural design
Flight chamber sizing, fan selection, and intake/exhaust duct engineering for the open-flow circuit.
- 3
Manufacturing
Fans, ducting, glass and controls fabricated in Stuttgart.
- 4
Installation & commissioning
Foundation, structure and systems installed on site, followed by acceptance testing.
- 5
Instructor training & handover
Instructor cadre trained and certified before the facility enters service.
Single-point responsibility, documentation and support appropriate to a defence procurement programme.
Start with your programme
Tell us who you're training, and how many.
Detailed JetFly specifications are provided on request to identified defence and government customers. Our engineering team will translate your throughput, equipment loads and site constraints into an initial facility concept.