Table 1 shows the datasheet of the aircraft, as presented on the manufacturer's website [16]:  
It is quite likely that an increase in the weight vs. thrust ratio might be achieved in the UAS by using a voltage below the usual 48-50 V of 12S batteries combined with high-diameter propellers. This hypothesis is based on the fact that high-efficiency T-Motors are not designed to operate with 30\" or 32\" propellers. Nevertheless, HYBRIX's datasheet, as well as others from other companies, must be read with caution. Since no standards exist for UAS product specifications, companies tend to show maximum values for all the variables, although they cannot be fulfilled simultaneously. For instance, an 80 km/h speed is possible without a payload but physically unreachable when flying with the MTOW. Aerocamaras (Lalin, Pontevedra-Spain) AEROHYB(tm) [19], is assembled in Spain. It uses a light commercial frame, a T-MOTORS propulsion system, a DJI A3 PRO(tm), Lightbridge 2 TM and a NOVA2400 TM hybrid generator. The maximum payload is 5 kg. Although no data are available, the extremely slim and apparently light frame result in an empty weight that is lower than GAIA2400 TM. This weight reduction will increase the thrust vs. weight ratio, and longer and more stable flights with greater manoeuvrability would be possible. However, its operation for 7 h is far from advisable, since the generator's manufacturer did not test it for more than 3 h because of heating concerns. Moreover, a 7 h flight implies the use of 17.5 L of fuel. If gasoline density (0.755 kg/L) is used to calculate fuel weight, the calculated weight is 13 kg, which added to the maximum payload (5 kg) gives a final weight of 18 kg (not including the frame and propulsion). Under these conditions, the MTOW of the aircraft will very likely be 25 kg, and the thrust vs. weight ratio will again be extremely poor. Both in this case and the case of QuaterniumTM, impressive flight time records have been presented. Although there is no doubt that these flight times have truly been obtained, they must not mislead customers. Using a very large fuel tank and taking off at the limit of a thrust vs. weight ratio slightly higher than 1 does not mean that operational flight is possible. If there is no manoeuvrability, flying above the mean sea level will be impossible, and even very low wind speed will prevent flight. One of the seemingly more advanced and efficient hybrid generators is GE70 TM from Pegasus Aeronautics [20]. Its design is compact and similar to our prototype. The BLDC generator has been installed, at least in the latest versions, inside a two-stroke two-cylinder carter of a 70 cc engine [21]. The engine is a Desert Aircraft DA-70 [22], whose power, at slightly above 5 kW, seems to the authors to be low for operation over medium- or long-term periods under the maximum output power of 4 kW. Table 2 shows the product's specifications. \begin{table}
\begin{tabular}{c c} \hline MTOW & 20–25 kg \\ \hline Empty weight & 13 kg \\ \hline Maximum payload & 5–10 kg \\ \hline Maximum endurance & 4 h \\ \hline Cruise speed & 50 km/h \\ \hline Size (motor to motor) & 80 km/h \\ \hline Propellers & 30–32” \\ \hline Operational temperature & \(-\)10–45 °C \\ \hline Propulsion system & Hybrid fuel—electric \\ \hline Combustion engine & Two-stroke \\ \hline Backup batteries & Li-Ion-Poly 6S \\ \hline \end{tabular}
\end{table} 
Table 1: Quaternium-HYBRIXTM datasheet. Although GE70 was presented to the press, some unknown variables exist in its specifications that could not be clarified even after contacting Pegasus Aeronautics. The overall base weight only includes the weight of the engine and generator. The pumping system, electronic control and heat exchanger are not included. The installation of the BLDC generator inside the crankcase is extremely close to the combustion chambers and shares space with the engine shaft. Sharing a heat-conducting component increases the temperature, and therefore the permanent magnets work at higher temperatures.