This is going to be a build thread on an electric powered version of Pat Kings 900 square inch version of the Magician. It will be powered by a turnigy 4230 700 KV motor .  I have been doing a couple of surveys of people who have flown Magicians to determine if i am going to do any mods. Pats plan involves a cut out cored fuselage core of 2 layers of 3/8 inch balsa covered with 1/8 balsa and glow power is .60 size. I debated using an aviastar .60 but i have not flown a glo stunter for years now. It also gives me the more options of how i finish the plane.

Questions are welcomed any time. Iĺl post pics as i get them.    bob branch

I should probably mention that there is going to be a major mod to the wing structure. I started laying out ribs and was stunned how much balsa wood it requires for all those big ribs.  Also note the cost and availability of good balsa that has been discussed recently on other threads here. Well, I decided to use the Detroit solution, an I-beam wing. It requires a lot less wood. There is a lot less cutting involved, no leading or trailing edge sheeting required and they are durable. With people like Rick Sawicki, Bob McDonald, and Dennis Adamisin as mentors and with Bill Werwageś excellent video on the method its a no brainer. Besides I am a Detroiter and have never built one. Sacrilege!! Yea, I just  want to build one. ...bob

The thing I really like about an i-beam is that it is a self jigging structure. The leading edge, spar, and trailing edge pass thru the tip ribs and fuse which are all squared to each other. The wing cannot thus help but be straight....to do that there are two requirements... the fuse has to jig straight with the wing tips which support and align the spars, and it has to do it right side up AND inverted. Note there is no straight surface to do that with at the aft half of the fuse due to the canopy and turtle deck... so I just cut the top off to make it straight with the top front edge of the fuse and to align with the wing tips... this is the cut having been made.

So obviously this requires a redo. But it offered a nice opportunity to do some destruction testing of that scarf joint. So verticle loading placed mid joint til failure. Think the result pretty well argues that the 45 degree splice with thick CA is all you need to get a solid joint stronger than the material... and we have not even started to reinforce the spar yet. I had kind of anticipated some comments about this joint so this was a nice opportunity.

now if i can figure out how to load pics again and resize them in this differenct operating systems I will post a pic of the fiuse core. I incorrectly said the core was 2 layers of 3/8 in balsa. That was incorrect. It is 2 layers of 1/4 inch. A layer of 1/8 balsa is laminated to each side and doublers of 1/8 ply. The doublers do not have to be that thick but there would not be that much rigidity lost in the aft end if I went to 1/16 sheet over the balsa. I will add some carbon tow for stiffness in the aft end along the top and bottom.

Bob,
 I built the prototype for Pat and it is pictured on his site in the vendors section. It was glow powered but the fuselage was also built slightly different.I did use the 2 center pieces of the fuselage but then I used 3/32 balsa cut at a 45 degree angle right to left for one side and reversed for the other side. You could probably use it as a club or a bat it is that rigid. Model was 65 ounces when finished . The wing requires a good jig as it is fragile till built but more than up to the job when finished.
The plywood sides for the motor mount area to the wing were flush mounted to the fuselage and blended in to the fuselage skin. It is a great flyer and you should be more than happy with your new giant killer when done.
The plywood

Photo of spar center section showing bellcrank opening from front view with doubler and trippler on each side and 1/16 ply bellcrank pivot anchor doublers top and bottom. Funny looking joint where this doubler meets top of the spar is because I relieved the edge of the spar across the center section... little inconsequential opps.

Next step is to sheet the fuselage. Have to do that before the wing is built. So the ply stiffening spars will go into the front of the fuse, the ply doublers placed on each side of the fuse, and the sides sheeting. In this case to the back of the wing. Could be all the way but the fuse has to remain with a flat top side til the wing is jigged and has ribs. Thus a little deviation for the sheeting of this particular plane. stay tuned.

A common practice today is to incorporate a thin sheet of carbon fiber under the spar caps and along the front surface of the trailing edge Since i am sing oversized main spar and trailing edge i have elected to forego this step. It was not done back in the day and what i have is certainly strong enough. Could use the spar as a cricket bat!  Feel free to offer any questions or suggestions.

Hi Bob

Sounds good. The final test will come with the stab installed permanently and the fuse is held gently in a vise and you can put one finger on each stab tip and try to rock it from tip to tip. Then you will truly know how much torsional rigidity you have. If I was a betting man I'd say you will probably be happy. 

Dan

Very good Bob. I'm interested in your results. 

Dan

You might want to consider a bigger motor. Assuming that you will end up with a 13-14in 2B prop that motor is going to be on the small size and get hot.

Why a rear mount instead of a front mount motor?   

Well dont worry, I have been working on the Magician, just not where a photo means much. Like sanding. Fuselage is all sanded. The ribs have been all sliced along with the half ribs. One of the convenient things with an ibeam is that the ribs are all created from the center rib template. The template is made from something hard. Some folks use aluminum. This had the advantage that when you are slicing the ribs with your preferred weapon (razor blade, scalpel, meat cleaver) the blade doesnt cut into the template. I dont do much metal work so i used 1/8 inch ply and hardened the edge with thin CA. Then I darkened the edge with a black marker so it had contrast visually with the balsa sheet i was slicing the ribs from. Ribs are sliced from 1/8 inch balsa sheet and are 1/4 inch thick. Measure the length of the template rib from the back of the leading edge which is 1/4 inch balsa to the front of the trailing edge which is sized to fit the front of the flaps thickness. Section it that length then tic mark each edge at 1/4 inch intervals. Set the rib template on the two marks front and back, hold it, and slice, preferably leaving your finger tip attached. Rib! Well half a rib cause you are going to have a top half and a bottom half, so you need twice as many as number of ribs the design calls for. Half ribs are also sliced the same way to be placed midway between the full length ribs. They go just past the wing main spar.

Some people use variouis forms of jigs to position the template to the sheet to slice the ribs. I am more of a connect the dots kind of guy. Always liked connect the dots puzzles as a kid too, and mazes!

The tip rib jig has been made too. It basically holds the tip aligned with the the center rib and holds the leading edge, main spar, and trailing edge in fixed position. The location, alignment, and incidence are all set with the two wing tip jigs and the fuselage openings that the leading edge, spar, and trailing edge pass thru. The fuselage top which is flat and aligned with the wing center line and tops of the tip jigs are all in alignment and flat to each other. Pics to follow.

outboard view of fuselage jigged wing. The bellcrank is a suspended mount with the pin going thru the top and bottom ply doublers on the top and bottom of the spar, ie thru the spar. It is mounted off center to the inboard of the spar and the and the fuselage provides the security of the pin. The bellcrank is also reverse ounted, a 4 inch unit.  The inboard pic shows the bellcrank more clearly and the positioning of the first few of the rib slices. The tic marks are at one inch intervals. Full ribs are at 2 inch intervals, half ribs at one inch intervals between the full ribs. Prior to mounting any ribs when everything was fully aligned the spar, leading and trailing edges and tip ribs were all glued with thin CA. The tip ribs will be cut to the rib pattern (drawn on them) when the bottom ribs are all mounted.  All rib slices are glued with thin CA. The rib slices are mounted to leading edge first, then to the spar and finally trimmed to length and glued to the trailing edge.the fit to the top of the spar should be complete. If any adjustment is needed at each rib it is done at the individual ribs with either sandpaper or a razor plane. It takes very little adjusting. The rib slices should fit flush to the top of the leading edges and about 1/16 proud if the trailing edges t allow for final sanding.

Sorry it has been so long to continue on this thead. My wife is in end stage cancer and i have not been able to leave her most days even to go downstairs long enough to work. So a piece here and a piece there. At any rate it is in the bones now and I took a few pics today to share where it stands.  Next will be sheeting the upper section of the fuselage and the pushrods and covering. Will update when more progress permits. bob

thank you John.... bob