ORIGINAL: Strat2003
I've read that most of the drag on a control line plane is from the lines. Any drag savings from a cowl would be a relatively small percentage of the total system drag, so you would'nt expect a big jump in speed. That same drag reduction on an R/C plane would be a larger percentage of the total drag, so a noticable increase might be expected.
yes - the lines make big drag- as a kid we tried nylon lines - steel lines braided steel etc..
on 1/2 A - .008 braided were best - -why? lowest drag. On speed the guys adapted line groupers which hopefully placed one line exactly behind the other- reduced deag thru better fineness ratio.
as forthe cowls--
one of those things which theory seems to say -OH YEH- got to have have em
well you did but the real reason was to insure the air was forced around the fins on the engine
some guys even removed almost all th fins and then fitted the pressure cowls.
On my ZDZ160 I made sure the airpath was around/thru all the fins - makes a huge difference in engine performance as it forces flow thru the fins.
On these flying wings-- same thing-