ORIGINAL: mk1spitfire
Ok thanks for replies. I came accross this too, what do you think?
10% infront about.
I notice this attatchment the tips are not pointed and have a cord instead. i guess you just omit this?
Pointed tips = all bad, lose them! They contribute nothing but drag and bad manners, except maybe the Buck Rogers look.
Although if you keep them, relative to the identical planform but with clipped tips the pointy one will have a slightly more rearward NP due to the increased rearward area, so I would use the same location for starters. If you wanted, you can do the workup precisely the same way, it is simply that the tip chord is zero so you plot from the LE apex to the extensions lines at the tip. Same thing as the attachment, except the extensions lines at the root are zero length.
Clipped tips are much better. Try to keep reasonable chord at the tips so the Rn is not too low. 4"? 5"? or so depending on size.
10% is fine. Unless something else gives you grief, like excessive throws or what not you ought to be just fine. Don't horse the elevator at launch! Actually don't horse anything. If you are used to aircraft like this go for it. If not, like any other model if unsure lean towards nose heavier of course. That's what uptrim is for, until you get it the way you like it.
MJD