E XPERIMENTAL and theoretical investigations were made of the A1203 coated peg-wall-type generator with a large-scale superconducting magnet. In Japan's MHD National Project, the many component apparatuses required for the MHD plant had been developed individually and these apparatuses had been combined into ETL Mark V and VI MHD generators in 1971. The ETL Mark V generator had as main components, a superconductin g magnet, the cold-wall Faraday-type generating channel, and a combustor of 25-MW thermal input for the purpose of investigating the generating characteristics in a strong magnetic field. The details of the ETL Mark V generator were reported elsewhere.l'6 Since the construction of this equipment, 27 thermal and three generating experiments have been carried out and the summary of these operations resulted in about 55 hours of thermal and about five hours of generating experiments. The maximum output power of 86 kW was generated in the first one, 193 kW in the second one, and 482 kW in the last one. This note describes the results of the last generating experiment and experimental conditions are summarized in Table 1. The calculated gas temperatures were 3050K at the combustor and 2680K at the inlet of the generating section for the mass flow rate of 3 kg/sec. Though the combustion conditions were different, the measured gas temperature was 2860K at the inlet of the generating section on the other thermal experiment of 3 kg/sec. The power generating time was 3.3 hrs. The central magnetic field strength was 4.2 T. The generating channel had 50 pairs of electrodes which were made of sintered copper (30%)-tungsten (70%) as cathode and stainless steel (AISI 304) as anode. The estimated surface temperatures of cathode and anode were 600K and 900K, respectively. The electrode surface area was 18x100 mm2 and electrode pitch was 36 mm. The cross-sectional area of the generating section was 150x100 mm2 at inlet and 241 x 100 mm2 at outlet and the length was 1764 mm. The generating characteristics were measured at each step of mass flow rate. The generating channel was constructed with 50 pairs of side and electrode wall modules whose flow direction length was 108 mm.1'2 The heat losses were calculated from measuring the water flow rate and temperature difference of every wall module. The heat loss and the fraction of the thermal input at the mass flow rate of 3 kg/sec were as follows: combustor-2.26 MW, 9.1%, nozzle-3.78 MW, 15.2%, total up to the inlet of the generating section-6.04 MW, 24.3%; generating section- 1.93 MW, 7.8%; downstream up toihediffuser-2.32MW,9.3%. Figure 1 shows the heat flux distribution for the mass flow rates of 2 kg/sec and 3 kg/sec and the calculated value for 3 kg/sec. The position of the nozzle throat was x = 0.7 m; the inlet of the generating section was 0.91 m and the outlet was 2.67 m. The heat flux varied considerably in the case of short