E-Props 4-pale sur le Zlin Norden Rotax 915iS

Zlin Aviation a écrit : “pour l’instant, l’hélice EProp 4-pales que nous avons installée semble être la meilleure lorsque nous combinons le roulage au décollage, la montée, la vitesse de croisière à différents régimes et la vitesse de pointe.” 😀

Rapport d’essais du 07-11-2020

Last updates about Norden’s progress.

We are preparing a new larger and slightly modified instrument panel that on demand, will be available for the customers interested to install the Garmin G3X or the Dynon Skyview in the 7” size. The basic renderings just show a couple of possible configurations, that could change of course according to the customer’s specific needs or desires. Radio and transponder for example, could be differently configured, leaving some free space for other 2 x 57mm round instruments.

We started to test a new AoA system made by the Italian company Flybox, tests are under process. The new optional and definitive carbon and leather seatings are now under production and have the same size of the prototype ones, just better made. We tested also a new prototype “very light” carbon cowling (the top half weights for example around 800 gr) with two new Naca air intakes to let the Rotax 915 breathe at best and after the tests, they are now available and in production. The plane was inspected by an official Engineer coming from the Czech LAA and passed the weight process, necessary for homologation process. We can confirm that the Norden with the Rotax 915 and some options as 22” tires, extended landing gear, shock absorbers and safety cables, aerodynamic cover for V cabana and s.absorbers, double brake calipers, aerodynamic covers for struts, carbon cowling, carbon wing tips, carbon seats, carbon floorboards, rear T3 system shock absorber, optional 140 lt fuel tank, baggage door and standard soft baggage, weights 380 kg (837 lbs). We already introduced some mods on manufacturing process, so the regular planes will weight few kg less. The next Norden we will produce and deliver to a Czech customer in December, wil be equipped with the Edge Performance 120 hp engine, and will weight about 27 kg less, compared to the Rotax 915 equipped prototype, so we could arrive at 350 kg empty weight with the same above configuration. In the future we will introduce even the carbon slats and this together with oracover covering process for the fuselage, should help for about another 7 kg saving, so just in prospective this plane will not be so far from the 340 kg empty weight in the close future, when all next light weight optionals will be available. Considering then the strict weight limits necessary to enter into the French market, we confirm that we are working hard in the attempt to meet them too in the future. Don’t forget that the large double slotted flaps and retractable electric slats have an impact of about 14/15 kg on our wings compared to a normal version of the same wings.

Now some new datas after new test flights and props setting .We confirm that similar performances are available with different variable ground pitch propellers but at the moment the EProp four blade prop we installed, seems to be the best one when we combine take off roll, climb, cruise speed at different rpm and top speed.

Last tests have shown with our pilot Ivo Cervinka on board:

Norden take off weight : 515 kg (1.135 lbs), 22” tires, temperature 14°C, Altitude 2500 ft , calm air, zero wind

Take off distance: around 30 mt (98 ft)

but on this we want to work much more in the future, using more advanced take off techniques .

Speed Test:

4500 rpm —> 158 kph IAS (163 TAS) / 98 mph IAS (101 TAS) . Consumption 16,2 lt/h (4,2 gph). Theoretical range :1408 km / 875 miles

4800 rpm —> 168 kph IAS (172 TAS) / 104 mph IAS (107 TAS) . Consumption 19,1 lt/h (5 gph). Theoretical range : 1260 km / 783 miles

5000 rpm —> 180 kph IAS (185 TAS) / 112 mph IAS (115 TAS). Consumption 22,3 lt/h (5,9 gph).Theoretical range :1.161 km / 721 miles

5200 rpm —> 187 kph IAS (192 TAS) / 116 mph IAS (119 TAS) . Consumption 25,1 lt/h (6,6 gph).Theoretical range : 1.070 km / 665 miles

5500 rpm —> 200 kph IAS (206 TAS) / 124 mph IAS (128 TAS). Consumption 31,1 lt/h (8,2 gph). Theoretical range : 927 km/ 576 miles

top speed —> 214 kph IAS (219 TAS) /133 mph IAS (136 mph TAS or 118 knots)

Notes:

with some aerodynamic improvements that will arrive for the standard production, we still believe we could reach better performances.

We are also convinced that with the optional future spring landing gear, the Norden could have hit the 230/235 km/h top TAS (143/146 mph).

We truly believe that the 155 hp Edge Performance engine that we will install soon, for one our Norden customer, will again improve the above numbers.

The theoretical ranges were calculated with the optional 140 lt (37 gallons) fuel tank. In the future we will develop also the 180 lt fuel tank for special markets or needs, allowing a max theoretical range of 1811 km ( 1125 miles) at 4500 rpm economic setting.

Climb Test

Climb speed 90 km/h (56 mph)

4500 rpm —> 950 ft/m

5000 rpm —> 1400 ft/m

5380 rpm —> 1800 ft/m

5450 rpm —> 1900 ft/m

Stall tests:

all tests done with engine on idle

clean configuration : 58 km/h (36 mph)

1st position flaps and slats : 52 km/h (32 mph)

2nd position flaps and slats : 49 km/h (30 mph)

3rd position flaps and slats : 45 km/h (28 mph)

Stall with power on : < 38 km/h (< 23mph)

Results :

we can safely confirm that our plane has shown in the last tests, to be able to fly from 38 km/h up to 219 km/h TAS with 22” tires , without encountering any kind of problem and still climbing more than well with just a ground adjustable propeller and that with more powerful engines coming soon, new prop settings and the next spring landing gear planned for middle next year, we could break the barrier of the 230/235 km/h, still being capable to fly at below of 38 km/h with power on, offering so a ratio between minimum speed and top speed of above 1 to 6.

The 29” tires compared to the 22” tested above, reduce the speeds by about 4 mph. We don’t want to test tires below 22” diameter, since if it is true that the plane would perform even better, we don’t want to damage the final aesthetic of the plane using smaller tires.

Back to tests…