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E-PROPS MANUFACTURING

 

1 - Blades

2 - Hubs

3 - Manufacturing process

4 - Balancing

5 - Tracking

 

 

The E-Props propellers are fully made in France, in the E-Props workshops, in Provence. The 1700 m² worshops are equiped with 12 CNC machining centers. The company has developed more than 185 propellers models (2018-11-19).

 

E-Props propellers CARBON range are designed and manufactured to be very light and strong. Materials and manufacturing process have been validated by many tests.

 

 

hélice e-props en composite

 

 

helices e-props propellers the strongest on the market

 

 

 

1 - Blades

 

- made in carbon braid, with continue fibers between upper and lower surfaces of the blade

- the epoxy resin is the resin preferred in aeronautics because it has very good mechanical and thermal properties, a small shrinkage in the molding, a big resistance to fatigue, a good dimensional stability and a chemical good performance, as well as an excellent adhesion on fibers.

- foam core with internal spar (D-Box)

- blade's foot with titanium ring inside

- 100% carbon, no metallic part = no galvanic corrosion

- internal shielding of the blades : injection at the leading edge of a special resin with Nanostrength® (ARKEMA product : high kinetic energy absorption capacity) => See the page LEADING EDGE PROTECTION

- the epoxy resin is including a high resistance to UV additive (UVA and UVB). Blades are polished with a perfect finition.

- unique ref number on each blade for traceability (RFID chip inside)

 

The HCF (Helical Continuous Fibers) process, specifically designed by E-PROPS, ensures an exceptional strength of the 100% carbon + epoxy resin blade, from leading edge to trailing edge, from blade's foot to tip.

 

To the contrary of the usual process called half-shell, used by most of the manufacturers of composite propellers, the carbon fibers are continuous between the top and bottom surfaces. The braid is made like a sock. The mechanical strength is increased and becomes very high : no risk of rupture by delamination of the leading edge, no craks on the blades or on the hub.

 

 

tresse carbon carbon braid tresse carbon carbone braid

special high-resistance carbon braid, with thousnads of carbon wires

 

 

cannelure hélice EPROPS NGDinterieur pale e-props carbonepied de pale hélice e-props ng-dtor acier pied de pale hélice E-PROPS NG-D

foam core with internal spar, titanium ring

 

 

e-props serial number on the blade foot

 

 

 

 

 

2 - Hubs

 

- full carbon + high temperature epoxy resin

- blades and hubs are made in the same material : no problems of interference, no galvaic corrosion

- Nord-Lock washers secure bolted joints

 

moyeu e-props hub

carbon hub with aluminium flange

 

 

modélisation moyeux carbone e-props simulation sofflerie numérique

analyzsis of the hub

 

 

3 - Manufacturing process

 

Blades and Hub : RTM (Resin Transfer Molding) manufacturing.

This process is used by Airbus for some critical carbon parts on the liner aircraft.

It is realized by following a strict cycle of temperatures. The cooking of carbon parts allows to improve certain properties, in particular mechanical and of resistance under hot conditions (carbon hubs : max T° resistance = 120°C for reduced engines and 170°C for direct drive engines).

 

RTM EPROPS

 

The workshop has three ovens : two medium-temperature / small ovens and a high-temperature / big oven, both managed by computer.

 

 

hélice e-props carbone pour ULM et paramoteurs

 

 

 

To assure a strict quality control and the reproducibility of the production, the components are exactly weighed very throughout the manufacturing. 15 weighings are necessary for a propeller for Ultralights / Aircraft.

 

A RFID chip is in each blade is inserted in each blade, with all technical data inside.

 

E-PROPS ensures the production monitoring by RFID and KANBAN method. These methods and tools optimize the manufacturing quality, reassure and fluidify the supplies, allow the real-time follow-up of the production process, the traceability of all the manufacturing steps, and offer a set of successful and reliable indicators.

 

 

E-PROPS suivi RFIDE-PROPS suivi KANBAN

E-PROPS : production monitoring by RFID and KANBAN

 

 

The E-PROPS team has designed and built from scratch an innovative machining centre to allow the dimensional analysis, the rectification and the finish of the carbon parts automatically, without dismantling of the part. It is equipped with a directional spindle on 5-axis programmed according to the digital definition of the part, with a wide tool store. The precision of measure by the scanner laser is of 5/100th of millimeter.
The scanner sweeps the carbon part, the program recognizes it according to ts database, then the different tools come to make all the finishing work: deburring, cut, drilling, sanding and polishing. All the stages between the molds and the stock are automatic.

 

E-PROPS CNC Machining Center with Laser Scanner

functionning video

 

Centrifugal load test of a carbon E-Props propeller (propeller for direct drive engine)

Results : safety coefficient = 7,2. The system carbon hub + blade can hold 6 times the maximal load during 1 hour without any damages (EASA CS-P asks only 2 times for certified propellers).

 

The team is using its 12 CNC machines to manufacture the molds and to facilitate each production step, in order to propose all types of carbon propellers, for each needs and each aircraft.

=> See worskhops

 

 

 

 

4 - Balancing

 

The E-Props propellers are precisely balanced, if possible with their accessories (spinners).

The team is using an electronic bench to balance the propellers, with 2 oscilloscopes.

The maximum tolerance accepted is 0,4 gr/m

E-Props propellers are well known to generate very few vibrations, due to their very light weight and to their very precise balancing.

 

Be careful : the blades have not necessarily the same weight.

To balance a propeller, the weight of both blades is important, of course, but before all the weight distribution all along the blade.

 

 

Example :

equilibrage balancing

 

 

The weights P1 et P2 of each blade apply respectively to centre of gravity G1 and G2, which are not at an equal distance on the center of rotation O of the propeller.

The balancing must be realized to obtain : P1 x d1 = P2 x d2

 

It is strongly discouraged to add weight to one blade, in order to have the same weight for all blades. The propeller would be then unbalanced, and can cause some vibrations.

In case of doubts, il is possible to returm the propeller to E-Props for balancing verification. Please contact us : [email protected]

 

When the propellers are light, good balanced with a very low tolerance, a static balancing is enough to avoid vibrations perception and vibrations consequences. In this case a dynamic balancing is not necessary.

 

=> MORE DATE HERE : Balancing / Tracking

 

 

 

5 - Tracking

 

Propeller track is the path followed by a blade segment in one rotation.

 

On E-PROPS propellers, the maximum tracking can be about 20-25 mm, even more.

If you have no vibrations, tracking is absolutely not important.

 

tracking helice

 

 

PROPELLERS FOR PARAMOTORS :

 

Do not put a rubber washer between the propeller and the reducer flange to reduce the tracking.

It is dangereous because the loads are transferred to the propellers screws and those screws can suddenly break.

 

 

=> MORE DATE HERE : Balancing / Tracking

 

 

 

HELICES E-PROPS HI-TECH CARBON PROPELLERS

 

 

 

série de pales NG-D

 

 

carbone e-props helices propellers

 

E-PROPS HI-TECH CARBON PROPELLERS AIRCRAFT ULTRALIGHTS PARAMOTORS HELICES ULM AVIONS PARAMOTEURS ELICA ELICHE PARAMOTORES E-PROPS HI-TECH CARBON PROPELLERS