superdave118

hey, Whats everyones advice on putting a .91 ducted fan motor on a prop plane? good bad? I was thinking of putting one on a plane of mine. If so what prop would you run and what pipe would you run? just looking for different options. also what about a .40 ducted fan engine? same questions.

MJD

My Feedback: (1)

Regarding the .91: Very good, if you want to go very fast on a clean airplane with the right prop. And yeah brother, it is a fine idea.

A typical speed prop size for such an engine would be in the order of maybe tops 10x10 but to take advantage of the top end power as small as maybe 9x10 or so. The difficulty is that you can't run glass-filled nylon props like APC or MAS at those rpm in that diameter - they do not have the hub or blade strength required. You need a CF composite prop.

Search around here for threads regarding Speedcup, OPS .65's, CF props - the information is all here if you root for it a bit. That's not blowing you off, I'm just saying there is a wealth of this info here if you can find it. If I trip on the list of links I'll put it here.

As to the .40 - no sweat, there are a variety of pylon racing props that are good to go and serve the bill nicely. And apart from the names you know, there are oodles of specialist manufacturers serving the pylon racers with good props. The requirements are pretty much the same - sit on the front of a hot .40 and spin somewhere north of 20k and go like chicken snot.

MJD

freakingfast

My Feedback: (3)

Here are two resent theads, one on 90 and the other on 40 size DF engines used with props :

http://www.rcuniverse.com/forum/m_7509866/tm.htm

http://www.rcuniverse.com/forum/m_7645422/tm.htm

And one very interesting thread, courtesy of “I-Love-Jets” :

http://www.rcuniverse.com/forum/m_79...tm.htm#8008176

lousyflyer

This is a Cermark F20 .60 size that I re-fitted with an OS91vrdf, and then I just kinda gave up. I may pick it up and try to finish it now that the weather is warmer. I cut a recessed area in to the side of the fuselage for the pipe to rest in, then glassed it on the inside. The slick canopy is from a helicopter - a Raptor, I think. my LHS had one on the rack and it was massive, so I trimmed away what didn't look right. The original canopies on these planes looked like the bottom of a two-liter soda bottle. It definitely needs a smaller diameter higher pitch prop. It's rough as a cob, but it should fly.