A flying club workshop or a small maintenance shop for light aircraft needs around 0.5 to 1 m³/min of air at 7 to 8 bar: a 7.5 kW 4-in-1 screw compressor such as the K 75, which delivers 1.1 m³/min at 8 bar with a built-in dryer and filtration, covers it. A maintenance hangar where three to five technicians are drilling, riveting, sanding and painting at the same time climbs to 1.5 or 2 m³/min: that is when you move up to the K 110 or the K 150.
What uses air in an aircraft maintenance workshop?
The tooling in a maintenance workshop looks like that of a body shop, with tools specific to aircraft structures:
- Drilling and riveting: angle and straight drills, rivet guns, blind rivet tools, deburring tools.
- Dismantling and reassembly: screwdrivers, ratchets, impact wrenches for wheels and landing gear.
- Surface preparation and painting: orbital sanders, primer and topcoat spray guns, blowing down before painting.
- Composite repairs: sanding fairings, cowlings and sandwich panels.
- General services: tyre inflation, blowing out filters, cleaning.
As a rough guide, at 6.3 bar a drill uses around 300 to 450 l/min, a rivet gun around 100 to 200 l/min, an orbital sander around 300 to 400 l/min and a spray gun around 250 to 400 l/min. These figures vary from tool to tool: each tool's manual is the reference. Our page on the compressor for aerospace covers every use, from subcontracting to maintenance.
How do you work out the air flow for a flying club workshop?
A flying club workshop maintains a few light aircraft. Usually two people work at the same time: one removes a cowling with a screwdriver or drills out rivets for replacement, the other sands a repair or inflates a tyre.
- One sander, continuous: 350 l/min, counted in full.
- One drill, in bursts: 400 l/min, counted at half thanks to the air receiver, so 200 l/min.
- Subtotal: 350 + 200 = 550 l/min.
- 25% safety margin for leaks and tool wear: 550 × 1.25 = 688 l/min.
- 20% expansion margin for a third station: 688 × 1.2 = 825 l/min, or 0.83 m³/min.
The K 75 at 1.1 m³/min covers that demand, with spare capacity for a spray painting session. If the workshop only inflates tyres, blows down and does a little drilling, the S 55, a standalone 5.5 kW screw compressor at 0.6 m³/min, is enough, but it needs a separate receiver and dryer.
And for a maintenance hangar with four technicians?
In a maintenance hangar, an aircraft check keeps several technicians busy at once. Take four simultaneous stations: composite sanding, a spray gun in the booth and two drills on a structure.
- Sander: 350 l/min, continuous.
- Spray gun: 350 l/min, continuous.
- Two drills: 2 × 400 l/min, counted at half, so 400 l/min.
- Subtotal: 1,100 l/min.
- With the 25% and 20% margins: 1,100 × 1.25 × 1.2 = 1,650 l/min, or 1.65 m³/min.
The K 110, an 11 kW 4-in-1, delivers 1.7 m³/min at 8 bar. If the spray booth runs all day or a bead blasting station is added, choose the K 150 at 2.2 m³/min. Our configurator applies exactly these margins, starting from your tool list.
| Workshop | Calculated demand | Recommended model |
|---|---|---|
| Flying club, tyre inflation and blowing only | around 0.3 to 0.5 m³/min | S 55 + receiver + dryer |
| Flying club, 2 stations including sanding | 0.83 m³/min | K 75, 1.1 m³/min |
| Hangar, 4 stations including painting | 1.65 m³/min | K 110, 1.7 m³/min |
| Hangar, continuous painting or bead blasting | 2 m³/min and above | K 150, 2.2 m³/min |
What pressure should you set for aircraft tools?
Most air tools are designed for 6.3 bar at the tool inlet. Allowing for losses through the dryer, the filters, the pipework and the hose, a setting of 7 to 8 bar at the compressor is right. Then set each station with a pressure regulator: a spray gun often works at a lower pressure, given by the paint manufacturer. Turning the compressor up higher does not make the tools more effective; it only increases the electricity bill and the leaks. See our article on what pressure to set on a compressor.
What air quality does a maintenance workshop need?
Water and oil in the air cause two problems in aerospace. They make tools seize and, above all, they contaminate surfaces: paint that will not adhere, a failed composite bond. The K 75, K 110 and K 150 include a refrigerated dryer and filtration, which treats the water for the whole workshop. Our compressors are oil-lubricated: carried-over oil is captured by the outlet filtration. For painting and preparing surfaces to be bonded, add fine filters and an activated carbon filter at the point of use.
If your maintenance organisation or the product manufacturer sets an ISO 8573-1 quality class, our technicians will define the treatment to install with you. Our guide to ISO 8573-1 air quality explains how to read that class.
The traps in a maintenance workshop
- The old piston compressor you inherited. It was fine for inflating tyres. As soon as a sander runs for ten minutes, it overheats, the pressure drops and water gets into the tools.
- The cold hangar. A network running through an unheated hangar condenses water in winter. Keep the compressor and dryer somewhere warm and fit drains at the low points.
- Hoses that are too narrow. A long, small-bore hose out to the aircraft loses a bar or more. The drill runs slower and the technician thinks the compressor is too small.
- Forgotten servicing. A flying club workshop runs few hours a year: the service at 500 hours, then every 1,500 hours, may only come round after several years. Follow the calendar intervals too, as set out in the screw compressor maintenance guide.
Send us your tool list and the number of technicians with a quote request, or work it out yourself with the configurator.
For your trade: Compressor for aerospace, aircraft maintenance and subcontracting.