hi ladies and gents !,
been lurking for a while and thought i'd come out of the weeds, of course, with a question. first a little historyto my intro......
i flew rcbriefly about 40 years ago and u-control before that for several years. i had a freind at the time who's dad flew and had a basement full of planes. it was my favorite place to be ,back then. one day he gave me a falcon 56 that he didn't fly any more and that was the start of my ******** as a kid. i found a used orbital 4-channel( remeber those little black boxes?!)and he helped me set it all up. well, it flew just fine, but it was a good thing the pilot was a talented kid, because i rebuilt that wing several times over about 5 years of "flying"! ......
i never lost my intrestin planes in general, but i never really kept up on what's going on in rc either.... boy has it changed from the late 60's!! .afterrecently retiring from a carrerin carpentry, iattended a fly-in at the local small airport . the local rc club was there and it fired up my desire to get back into flying, now that i have all this time on my hands. next thing i know i bought a futaba 6ex and a small pile of balsa. i downloaded a print of "sumpin else" ( love the pylon planes for looks) and ran off to kinkos to blow it up to 40-50 size ( 56.5" W.S / 49" fuse). a few mods to thin the fuse out a bit, reduceit's profile height(752% expansion made the fuse look just a bit too tall for it's length),fatten upthe airfoila bit so it flies better at slower speedsand re-locate the wing to shoulder height...in all a pylon looking mid-star 40 typewith a t-tail.afew weeks of cutting and sanding and the airframe is done, basically ready tocover at this time.if i could post pics i'd take some and show you guys, it's actually a pretty neat looking plane.
havingdealt with blueprints my entire life, there were no problems building the plane and after a lifetime of building just about anything you might imagine out of wood and or steel ( i am lso a certified welder) there's not much drawn on paperthat i can't figure out. i made all the necessaryadditions of material size and parts, if anything, i'm currently thinking i might have gone a bitheavy onthe wing....spars( 5/16"s x 1/2" spruce full span), sheeting, (3/32" D-tube/ LE shaped fron 5/8 sqaure light balsaand 3/32"x3" hollow), the wing is definatly stiff!....but if it proves to be too sluggish, i'll just build a new, lighter wing. i haven't weighed it, yet. but it seems like when youfirst pick it up it's light, but then, the more you hold it, the heavier it seems to be....only time will tell i guess.i didbuild a wing jig, so it doesn't takelong toput together a wing.
this great site has helped allot as well. everytime i had a question i was lucky enought to find an answer by searching the scratchbuilding threads.
that pretty much brings me up to the current state of my" re-introduction" into rc flying. i have already made arrangements with the local club to buddy box my first few flights, so this spring's gonna be fun!
now for the question.......
the print states 0/0 incedence and offset for the .015 size racingairframe. i've already built 3 down and 2 right into the firewall as the wing is now muchhigher than the thrust line and the plane will be doing more than just left turns, so i think i'm ok there. but what about the incedence?.... do you think i might want to change that because of the expotential increase in weight as the plane gets considerably bigger. wing is basic flat bottomed and tail is trussed flat slab. both essentially identicle to the plan, just bigger with a bit more airfoil thickness than the expanded profile.
i realize that i essentially built a completely different plane than the original design would yeald, but that's the fun of this hobby, and if it doesn't fly, oh well, build something else!!
thanks for taking th time to read this and i surely will appreciate any comments and advice.
ron

Welcome to the RCU forums, Ron.

I suggest discussing the use or not of this plane with your future instructor.

A traditional trainer may be more suitable for a re-start; at least during the first weeks.

Regarding the incidence, I would leave as is until the first test flights prove otherwise.

May be your instructor feels uncomfortable test flying and trimming your modified design for you.
If you try doing it yourself, you may damage the plane.

Best luck in your re-training.

Hi Lnewqban,
you bring up good, well takenpoints, all of which ran through my mind as well . thearrangement to "buddy-box" also included some time with a trainer plane first, the club has a few that are set up just for the purpose of breaking in greenhorns like me (believe me, i make noclaims to retaining muchmore than a rudimentary idea about flying an rc planeafter 40 years!).... i'm well aware it's not like riding a bike!
my thoughts about theincedence as about the same as yours....leave it as is and see how much trim it'll wantfirst, thenmake adjustments to get rid of the largetrim inputs
i've already discussedthe mods/scale-up and initial flight of my plane and the consesus is that it shouldfly, as itwas pointed outto me thatwhat i built was, for all practical purposes,a mid-star40 with a T-tail andjust bit more "pylon-racer" looks. i set out to end up with exactly that. i liked the mid-star, but wanted more pylon racer looks.i suppose i could have just bought a mid-star kitandadded the cosmetics to make it more racer looking, but i enjoyand have a good understanding ofthe "designing/building" part of the hobby maybe even a bit more than the flying part...i'vealways been that way,... abuild-it-rather-than-buy- it type,... maybe to fault,... as ultimatly, the goal is to fly, where i sort of look at the flying as the "by-product" of the effort put into the designing and building of themodel.i have no reservations about piling it up if i built something wrong, or it not flying very good because it's so far deviated from the original design, that goes with the territory!

Because you're using the model as a trainer you'll be running with a CG location that is slightly ahead of the original racer.  Because of that you'll find that you end up with the elevator angled up from the up trim that the test pilot will add during the first flight.  To avoid the elevator always having this up angle you can add a degree of positive incidence to the wing's leading edge and a degree of negative incidence to the leading edge of the stabilizer.  Setting up the model for a 2 degree wing to tail difference like this will reduce or eliminate any up trim needed in the elevator.

One way or the other you'll end up with the trim in place.  It's either you build it in or you deflect the elevator.  In the end it adds up to the same thing.

thanks BMathews,
     so basicly, a bit of "nose-up help" (?)....  wondering if the wing being moved from low (as on the original print) to shoulder (as on a mid-star)  will move the center of drag up enough to do the same thing? wing and to a large part, the (assumed) drag center moves from below to above the thrust line, close to equal amounts. with that in mind, will it still need the nose-up incidence, as well?    not questioning your help, just wanting to know if my thinking that, " moving the wing up would do the same thing" is correct or not.
     i have to say that i never gave thought to moving the C/G ahead, as the drawing shows it pretty much at the thickest section of the wing, which is where i put the spars. i imagine the the incndence relates to the C/G move?

It will but not enough. You will still want a bit of angular help as well.

Yes, the addition of someincidence is related to the CGmoving ahead a bit and also to the fact that you won't be flying it at the sort of speeds that a racer would use. Basically you want the model to be a "sheep in wolf's clothing"so it looks sleek but has the manners of a trainer.

Later on as you get comfy in the air and with handling the model during landings you can inch the CGback a little at a time and re-trim the elevator. The model will become increasingly more neutrally stable as you do this. At some point you'll find the happy spot where it flys well as a sporty model. At the same time you can increase the amount of control throws for all surfaces and go from a soft responding trainer like flyer to a pretty snappy sport flyer.

 BMathews,
       you hit the nail on the head!!!  just exactly what i needed to hear. the "sheep in wolve's clothing" is exactly what i wanted to achieve with this plane. as both the the wing and the H. stab are mounted on flat planes, parrallel with the thrust line , changing the angles is easily and accurately done with shims at the mounting screws. the H stab is mounted on a flat  platent epoxied on top of a 5/16" built up verticle stab with elevator linkage running through it and the el. horn set up to work inside the stab to keep the tail surfaces clean on top.  actually, i even made provisions for eventually re-mounting the wing in it's "as designed position", by putting the root airfoil into the plywood fuse side doublers. so i could essentially move the wing back down as i get more accomplished as a pilot, by cutting the fuse side out to the airfoil and rebuilding the top of the fuse to it's as designed profiles.......that is, of course, if the planes makes that far!!.   it is a nice design and easy and fast to build, so i imagine i'll probably build more than just this first plane to that plan. one might say it's kind of an "advanced" plane for a first plane in 40 yrs. , but the building part of the game is the easy part for me.   i'm one of those guys who, as a kid, was reading "popular mechanics" and "mechanix illustrated", while all my buddies were reading "spyder man" and "mad" magazines. this build only follows suite to my style, as a 14-15 yr. old i built a nobler my first u-control plane, and of course, it got "re-built" a time or two.