I think I posted this in the wrong place so here goes again. I have a Starfire jet airplane 53 1/2" wing, to be powered by a Rainbow ducted fan unit that comes complete with the motor. This fan is 101mm and the motor is a 2100kv brushless. It will turn at 30000RPM using 85 to 100 amps. I am using a 100amp speed control, and a 22.2v 3000ma 35C lipo battery. If anyone has used this unit I would like to know how it preforms? The plane will weigh about 5 1/2 pounds total. The second question is the fan and motor came complete with all the hardware except the screws used to mount the motor to the fan housing. I would guess they are metric. The motor is red and measures D36XL50 and is finned. If anyone knows the size of these screrws I would like to know, as the motor and the fan contained no instructions? This is my first ducted fan electric jet. Thank you

Probably 3mm but could be 4mm screws. If they look almost identical in diameter to 4-40 they are 3mm; larger then they are 4mm. Homedepot sells the 4mm but not the 3 IIRC.
I have the same fan but got it wihtout the motor for use in the Nitroplanes Predator. I'm putting an 1100KV 36 x 70mm Quanuum in mine and running 10 or 12S. I can't remember the specs I got in it when I ran it up but the amps were of course quite a bit lower and watts were similar.

I'm pretty sure Rainbow is the original British company that sold out the tooling and is not in business any longer. It is the same fan sold as a combination by Himax with one of their motors. An extensive thread wtih lots of information is avialable on RCG here: http://www.rcgroups.com/forums/showt...t=922350&pp=20

If you ever want to get one of the fans only, I bought one here for cheap:
http://www.hobbypartz.com/10eldufanun.html

Thanks Mark, The mounting holes measure 3 mm across the top. I will check out both sets of screws (3mm and 4mm). The link has the same fan unit as I have the only differance is the color of the fins on the motor. I will have many questions as I have no experance with electric flying. I have a programable speed control andf i will need to know what settings to use. Ramp up hard accel. or soft? Break or no break? Soft or hard cut off. Thanks again

Go with soft ramp up, start with the lowest advance setting and see how hot the motor, esc and batteries get (more advance= more power and heat usually), soft cutoff unless you would like the throttle to suddenly cut off when the battery reach cutoff voltage. Not sure what break is, you'll need to look at the esc documantatin to see.

Thanks again Mark. I think the break has to do with how fast the motor stops when you shut it down. The choices are "no break" "soft break" "medium break" and "hard break". It comes preset to soft break. It has a bunch of programable settings. Most have factory presets except for the the number of cells. Cut off voltage is set to factory standard when you select the number of cells, but it can be changed. Thanks again for your help.