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-   -   enough engine ?. (https://www.rcuniverse.com/forum/s-p-d-aircraft-coroplast-design-178/11628474-enough-engine.html)

ron ward 04-10-2016 07:24 AM

enough engine ?.
built a "Spadet" to reintroduce myself to r/c after not flying for quite some time. I used a Super Tiger .40 that was given to me and added about 7 inches to the wingspan. (from 64" to 71") by using full 3 ft wing panels instead of the 32" panels that the plans show.. this net a 7 inch increase in span after trimming and joining panels.
my question,..... do you think the ST.40 is enough power considering the plans show an OS.46 being used but they also state that the Spadet is for,.... ".40 size engines"..
then,... would it pay to use an 11-4 prop instead of a 10-5 or 6 on that .40 ?.
keep in mind that it s a trainer and I do want it to just put around at first. more engine, of course, can be easily installed later, but if I don't/won't need it, I don't have to spend the money for a bigger engine right away.
as always,....thanks for the replies.

aspeed 04-10-2016 08:51 AM

I don't think it would hurt too much to try it. You can always cut the wings back to the regular size. The .46 motors would need to be throttled back for most of the flight anyway. An 11-4 sounds good.

All Day Dan 04-10-2016 09:36 AM

Ron, did you increase the horizontal stab area at the same time? If not, you may wind up with an unstable plane. You can offset this by moving the CG forward. Be alert during your first fight. Dan.

ron ward 04-10-2016 02:02 PM

yes I did,,,, I increased the horizontal area proportionally to the increase in wing span % of increase and the elevator area was increased exponentially, giving an increase of elevator surface over the proportional increase of control surface. IOW,...bigger horizontal control surface and a bit "bigger than proportionally bigger" elevator surface. the increase amounts to 11%.

Clean 04-14-2016 06:34 AM

Stick with the 10x6.but take an 11x4 and 11x5 with you. I started flying using my CL engine and an 11x4 prop, it was hard getting up to flying speed. There was much more thrust on the 10x6. The 11x4 would get it out of the chocks quick but it didn't have the legs at higher speed.

It's not like you're going to be hovering this thing.

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