My (Kyosho’s German) instructions say that the drag would be too high; I rather suspect that you would break them on every landing - unless you install an UC.

Don’t use 7 but at least 8 cells, the fun starts at 10 cells - but not for long. I covered the fuselage with 1/2 oz glass fabric and water-based polyurethane varnish. The duct exit diam. is a little bit on the large side (62mm diam. A~30sqcm) and can be slightly reduced with a part of a yoghurt pot or a cross-grained balsa wedge ring to about 58mm (2.28"). It also helps to chamfer the end of the fuselage outside to reduce the blunt duct end. I made a balsa ring 2 x 35 (as above) which is epoxied to the inside of the duct, then reduced the outside diam. to 60mm before covering with glass.

As for the inlet - this seems to be rather small (~32sqcm). Apart from rounding the lip edges, I enlarged it by sanding into the styrofoam towards the middle of the fuselage, at the same time removing that ungainly step in the fuselage side. There is enough material to enlarge the inlet duct on each side by about 2.5-3sqcm. The cheater holes I have closed - in my opinion they are counterproductive. The biggest problem with Kyosho’s T33 (internal flow wise) is however the extremely large cross-section area where the two side ducts merge: 51sqcm.

This means that the air flow is first retarded and then again accelerated. Many people have tried to alleviate this problem to a certain degree - it needs some appropriately shaped duct pieces, which would also cover that aileron servo. I’m thinking about it.

Otherwise it’s probably the best EDF beginner’s model one can think of.