WHAT EXACTLY IS A HEAVY DUTY IMPELLER?
We made it our mission to improve one of the most sensitive areas of our JetSurf boards. Our goals are:
- Insensitive to water and salt water
- Low weight
- Compatible with existing turbine housings
TYPICAL DAMAGE TO THE IMPELLER
WHen debris gets into the intake of the jet pump, quickly damages to the carbon blades of the impeller occur. From little chips up to the total destruction of the impeller everything is possible. Pictures below show some examples.
Damage like this usually required exchange of the complete jet pump. And it has been replaced by a spare part as sinsitive as the old one. We usually ride on natural waters like rivers and lakes with a present danger of debris in the water, so we wanted a more robust solution.
PLANNING AND CONSTRUCTION OF HEAVY DUTY IMPELLERS
Main goal of construction of HEAVY DUTY IMPELLER was a 1:1 fit into turbine housings of 2017 and younger models. What is the problem with older turbines? Impeller diameter is different and a small gap between impeller and housing exists, which hampers performance.
Construction of HD Impeller was done at the computer using CAD programs.
HOW DOES HD IMPELLER WORK IN REALITY?
First of all, we measured our HD Impeller prototypes exactly in our workshop in order to identify any mistakes and variations during production by our German-Dutch partner. After intensive control, impellers have been installed in original turbine housings.
- 2015 JetSurf Factory GP
“Old” turbine housing with bigger diameter; turbine housing undamaged.
- 2017 JetSurf Race with 2019 turbine housing
“New” turbine housing of a 2019 Race Titanium. Conversion of coolant hoses to different connectors. Turbine housing undamaged.
We show you the particular result right here.
TEST-IMPLEMENTATION with 2015 FACTORY GP and 2017 RACE
Turbine housings of older JetSurf models have a slightly bigger diameter than recent turbine housings. Therefore, a small gap remains between impeller and inside wall of turbine housing. But we wanted to test this effect in particular and wanted to investigate possible effects on performance.
Test rides have been conducted on a water body without drift; air temperature 10°C, water temperature 4°C, no wind, identical test rider for all rides.
Second test meeting has been conducted on a river at high tide with a larger than average amount of debris in water. Air temperature 14°C, water temperature 9°C, continous wind from south-west.
Mechanical fastening of impeller to shaft did not lead to any noticable vibrations. Rather important is a perfectly straight shaft that doesn’t show any play or lateral shaft in the area of the coupling to the engine. This could lead to massive vibrations that sooner or later destroy coupling or other parts of the board.
The impeller has been exposed to debris constantly. Contact with debris did not lead to engine stalling. Final inspection of impeller after the test rides only showed minimal marks at the front edges of the blades; no destruction or deformation of impeller. The video below shows the impeller removed from turbine after the test rides.
We assess performance of both test-boards seperately.
- 2015 FACTORY GP
- Original setup
- Minimal gap between impeller and turbine housing
- Acceleration subjectively unchanged
- Vmax measured with GPS device 48.8 km/h vs. 48.0 km/h with original, undamaged impeller
- 2017 RACE
- Race Pads and Ratchet Straps by JetSurf Race Titanium, HardRacing MagicFins Frontside, Backside, Main
- Optimized gap between impeller and turbine housing as we used a 2019 Race Titanium turbine housing
- Conversion of coolant system to different location of hose connectors
- Acceleration subjectively slightly better
- Vmax measured with GPS device 57 km/h vs. 54 km/h with original, undamaged impeller in 2017 turbine housing
ATTENTION: Data we measured is depending on many factors like condition of board etc. So we CANNOT guarantee your board will become faster or will accelerate better. Furthermore, geometry of impeller has been designed for universal use and not for improving Vmax.
One of our goals was weight reduction and therefore reduction of spinning masses. The original impeller (carbon) with its stainless steel shaft weighs 420g; our HD impeller (anodized 7075 aviation-grade aluminium) weighs 342g including the titanium shaft. Therefore our HD Impeller is 18.5% lighter than the original impeller.
This goal has been met. During preparation and conduction of our tests we had to install and uninstall turbines multiple times. Complete disassembly of the turbines was necessary; removing impeller from shaft worked without any problems. So you can replace single components smoothly.
Our intention is to test our impeller in various JetSurf Race Titanium boards in near future. Production of HEAVY DUTY IMPELLER Serie1 has started and we expect first kits available for sale soon. Price will be around 1000€. This sounds very pricy, but high production costs (5-axis CNC mill and anodization) for impeller and titanium-shaft require this.
As soon as HD Impeller Kits are ready for sale, we will publish this on our homepage, Facebook and Instagram.