Saro TG263 Insanity, committed and beyond fantasy

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Re: Saro TG263 Insanity, committed and beyond fantasy

Postby TASSE » Thu Dec 16, 2010 4:01 pm

Hi Will its certainly looking the part, but dont forget the floats.

Roy.
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Re: Saro TG263 Insanity, committed and beyond fantasy

Postby BillG » Thu Dec 16, 2010 11:58 pm

TASSE wrote:Hi Will its certainly looking the part, but dont forget the floats.

Roy.
Funny you mentioned that now. I just finished gluing all the float balsa sheet sections together. I enjoy sculpting, so I had to get started on them. The lines one the A1's floats make them an interesting part to model. I've nearly depleted a generous quantity of quality 1/4" balsa stock that was donated to me by a fellow modeler. I believe that this will be the 4th set of floats made from laminating profile sections, cut from the wood. I was up so late last night on this project :shock: that if I don't pass out soon, I may sculpt them tonight. I find these unusual projects to be quite motivating. You don't have to push yourself to work on them.
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Re: Saro TG263 Insanity, committed and beyond fantasy

Postby HO229 » Fri Dec 17, 2010 12:36 am

Well friend,
I guess it's offical :D

Look forward to seeing it complete!

Dave
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Re: Saro TG263 Insanity, committed and beyond fantasy

Postby BillG » Sun Dec 19, 2010 4:40 pm

Good to see you here 229. This great site has the best references for this build, so it deserves to have it logged here.

Here's the floats Roy. Not quite the perfect shape, but I'm burned out from sculpting them, so I think that they will do the job. I cored enough weight from the initial laminate sections, that I will probably not cut them open to core further weight, and then have to re-attach. After finishing the sculpting process, they are under 10 gms each, and within 0.1 gm. Interestingly, if you can match the weights of the unsculpted cores, then you can use weight as a method of determining which one requires more work. After noting that one is heavier than the other, I can usually examine it and determine what area/s need more sculpting.
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I've been using the GWS plastic landing gear mounts for float mounting and other tasks, for quite some time now. Bending the wires and tweaking the bends to obtain the proper insertion force is a bit of a pain, but they work well. The "proper" force being where you can insert them without breaking the wing, yet they do not fall out. The main reason that I like them, is that if the float strikes something, such as even a car door jam, they will give a bit. I also will tie control line string from a small screw on the wing, to the float, so that I do not lose them, if they were to fall out.
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A few more stringers to add on the bottom, and then it's sheeting time. I've been playing around with sheets, trying to determine how they will attach to the plane, where they will seam, etc. Decisions, decisions......
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Re: Saro TG263 Insanity, committed and beyond fantasy

Postby HO229 » Sun Dec 19, 2010 8:10 pm

Bill,
The dog leg in the float wire… is that done so it can be removed from the wing?


Dave
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Re: Saro TG263 Insanity, committed and beyond fantasy

Postby BillG » Wed Dec 22, 2010 1:37 am

Dave the wire is removable, but fits fairly tight. The idea is that the wire mount will move, if the floats strike something. I probably will install a small screw on each wing, and secure them with a length of control line string, as I really do not want to lose one and have to sculpt another.

Maybe not the best water proofer, but better than leaving the inner hull bottom sheeting untreated. The sheeting is a reasonably light 1/16" balsa, that is thicker than much of the 1/16" I have bought. The additional sanding latitude is working well, as I'm not a fan of filler. The darn balsa fillers leave a resin "flash" hardened layer between coats, that makes it difficult to sand evenly, and also are good for warping the balsa. I try to apply the sheeting as well a possible, and use as little filler as I have to. Some of my earlier sheeting jobs had cans of filler on them.
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I talked myself into adding framers for the hatch opening headers. I probably won't make it removable, but if I ever have to, I can simply cut through the covering, the top keel, a few stringers and remove the hatch. The sheeting is already cut at the hatch opening seam, so I should be able to see the lines under the covering. They are also basically where the cannon access hatch seam lines are, so it will look like a scale detail. I'm hoping the fan treats me well, as I don't want to weaken the fuse with an opening, unless necessary. There are enough stringers that it should still be reasonably strong, if ever removed.
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I've mastered large sheet sheeting, as I'll do anything to avoid strip planking. After a bit of head scratching, I came up with a cut pattern for sheeting the fuse sides that worked well. This certainly was NOT one of the easiest fuses that I've ever sheeted. The curve isn't that heavy, but forming the balsa over the initial flare of exhaust bulges is difficult. I'll have to build another plane like the Loening XSL-2 after this, with nice flat panels.
Just to note, my method of sheeting is to use BSI gap filling thick CA, and lot$ of it. You apply it to the framers at 9000 miles an hour, make dead certain to set the sheet straight, as you only get one chance, and then work it all down at 50,000 miles an hour before it sets. It makes sheeting a real challenge, as you're doing such a tedious task, and yet you have to GO GO GO!
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You can't quite cover everything with one sheet.
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Cut through the top keel and a few stringers, and the fan access hatch can be removed.
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The wing panels are test fitted in place. The wingtips still need to be sculpted, and the tape is used to prevent sanding of the wing sheeting. The wingtips were cored before gluing to the wing, to lighten as much as possible.
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Re: Saro TG263 Insanity, committed and beyond fantasy

Postby mcg » Thu Dec 23, 2010 12:17 am

It is interesting to see how subtle is the transition between the fuselage and the beginning of the bulge that accommodates the engine. On the Jetex model of the A/1, the instructions suggest we actually snap the stringers at the point where the bulge joins the fuse in front of the wing. This must have made a very noticeable crease. In your model the transition is so naturally faired-in that it is essentially invisible. Nice!

mcg
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Re: Saro TG263 Insanity, committed and beyond fantasy

Postby BillG » Fri Dec 24, 2010 6:02 pm

mcg wrote:It is interesting to see how subtle is the transition between the fuselage and the beginning of the bulge that accommodates the engine. On the Jetex model of the A/1, the instructions suggest we actually snap the stringers at the point where the bulge joins the fuse in front of the wing. This must have made a very noticeable crease. In your model the transition is so naturally faired-in that it is essentially invisible. Nice!

mcg

Thank you Michael. On the full scale, the transition is very gradual as you stated. I had quite a time making sure that the sheeting was fully pressed into the beginning of the blend, to accomplish the gradual blend, as you need 6 hands to apply sheeting the way I do. :D Fortunately, I had the insight to realize that I would need some solid balsa backing in that area to apply the sheeting to, as well as just stringers. The sheeting really has to be pressed in there, and would pull the framers out, if they were not reasonably solid.

Simple aileron construction. The thick header allows for a rounded LE to mate with the concave wing header. After all the effort put into the elevator hinging, I figured that I may as well give the ailerons the same treatment. The reinforcer plate stiffens the area where the control horn mounts.
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The rounded aileron header and wing socket are not perfect rounds, but they are fairly close, with the hinge pivot recessed near to the center of rotation, all done for the setup to work well. If not close to the ideal circle with the rotation point in the center, the needed gap becomes so large that it defeats the purpose of the design.
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The hinges are recessed to move the pivot point rearward.
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Here's the plan so far. The cocpit tray with pilot is removable, but will stay mounted in the plane, for battery access. The cover plate rearward of the tray will probably be attached to the canopy, and will be removable for battery access. I'm still deciding how the canopy/hatch assembly will be secured.
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Held in place, the cocpit/hatch/canopy fit can be seen. With an ample hatch securing method, it is not mandatory for the canopy front to be secured, as the fit is snug.
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Re: Saro TG263 Insanity, committed and beyond fantasy

Postby BillG » Wed Dec 29, 2010 10:15 pm

The cocpit and pilot tray are removable, for ESC and fan duct connecting tywrap belt access. I hope that I never have to get in there for either of them, however. The canopy is glued to the rear cover, which is the servo access and battery cover. There are a number of ways this can be latched/magneted in place.
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This photo jumps a bit ahead in the sheeting process, but shows the canopy/hatch fit to the fuse:
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Remainder of the hull bottom sheeted. On the full scale plane, there is a small flat area with no rounding, at the beginning of the vertical step portion. I may sand a bit of this in. I don't want to accomplish this by padding/sanding, as the step is already a hair rearward, due to the slightly off-scale, enlarged wing chord. Without designing all these details ahead of time, there are always a few surprises. I've read that a bit aft of a step will cause a higher takeoff speed, but still possible if not grossly rearward.
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The gradual process of sheeting the exhaust bulges. While I've sheeted many planes, this build has taught me some new sheeting techniques, etc. While obvious, placing seams on curved surfaces makes it easier to sand the glue seam, without over sanding the balsa adjacent to the glue seam. Knowing things, and practicing them are still two different things. :D
Sheeting with thick CA adds excitement to the process. :shock: You have to decide what areas to partition and glue at each session, if you cannot glue the entire sheet at once. Getting the glue into the tight crevasses can be a task. You tend to waste a bit also, with advanced techniques such as applying loads of glue and letting it run down into the crevasse, and drop bombing glue. :D
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It would be nice to cut the sheet as shown below, at the start of the process, as it would form easier. If you do however, you will inevitably break off the leg portion. The front was glued down first, before making this cut.
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Forging ahead:
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Every now and then, you have to install the wings for the motivational stare:
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Working out the vertical stab and rudder assembly process. The rudder frame will be cut, to fit over the scale horizontal stab extension. This is a feature that I considered blowing off, as it weakens the rudder. Note the gussets at the rear of the area that will be cut away from the rudder. The rudder TE balsa is very hard/strong balsa, to provide strength. Once hinged and in place, it should have ample strength. I could make a joiner "U" bar across the cutaway, but it would interfere with the elevator joiner bar at the hinge line. It would thus have to be moved rearward a bit, and the h-stab extension piece would need to be slotted, to allow for the joiner bar to move along with the rudder. This shouldn't be necessary however, and would be a bit of a pita.
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The rudder now has balsa added to the hinge line, and is shaped round to fit in the corresponding socket. This is not seen yet in the photo below. The idea is that the rudder torque arm rotation center and the hinge pins, are both aligned and recessed somewhat in the rudder. Done ideally, they would be on center of the perfect half circle at the hinge line. I did not make a perfect half circle however, as I don't need 180 degrees of rudder rotation, and because I would have had to pad out the v-stab hinge post further, to have enough material to dig out. Heck, the rudder can't rotate that far anyway, without crashing into the elevator. Good enough is good enough.
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Putting this post together was almost as much work than I have in the plane so far. :shock:
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Re: Saro TG263 Insanity, committed and beyond fantasy

Postby BillG » Sun Jan 02, 2011 7:39 pm

If I keep going without sleep, :shock: this build may be another personal record, in terms of build time. Only 5 weeks or so into it, as of now.

The tail feathers and control surfaces will be test fitted, and assembled later. There is a specific assembly order, with the internal linkage. I also do not want to handle a large fuse while covering, with tail surfaces mounted, so they will be installed later.
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The vertical stabilizer top is sheeted, but not glued to the hinge post.
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The pics are not out of order. The top v-stab section is now removed, after sheeting.
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Temporary assemble for some bare bones photos.
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Have no fear, even a plane that seemingly was going to have nose heavy issues, ended up a tad tail heavy, for a 25% MAC cg setting. About 1oz of lousy lead used for balancing. I inserted it from small cuts in the top of the ducting, and used gravity to manipulate it into the position shown below. Small holes were made for glue insertion, and then filled-sanded.
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The last balsa piece to be fabricated! (or so I hope) The small horizontal stab extension is test fitted in place.
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My New Years resolution: Never again use metallic Monokote on small floats. It's more work than sealing/sanding/priming/sanding/priming/sanding and painting them. Aren't they cute though? :D
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Yeah, I know, I said that I wasn't going to cut this open unless I had to. I thought I may have to remove the fan, but ended up not having to. I bench tested the fan and it seemed smooth, but should have done a real, high power test. Installed in the plane, there was a consistent vibration throughout the rpm range, that really resonated through the plastic ducting. With no rpm related harmonics, it didn't seem like the classical out of balance rotor condition. I thought that I may have a motor with a bad bearing, as it takes very little bearing free play to cause issues with ducted fans. Now that I have the cover off however, I can cover around the corners and do a proper covering job, for a removable cover. I still may install it after covering the corners, and then completely cover over it. I could avoid building a latch mechanism that way, and if I remove it at a later date, it would be fully covered, and I would only have to iron down the edges, after cutting the seam open to remove the cover. I added reinforcing balsa spars along the opening, as there is some weakening after cutting the hatch. With all the stringers, sheeting, and the added reinforcing spars, the fuse seems amply strong with the cutout.
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The fan runs smoothly now. A simple reorientation of the rotor on its collet adapter of 90 degrees, and it is now perfectly smooth in operation. Apparently either the collet, rotor, or both were a bit eccentric. I found the position where the blade tip clearance was the most consistent, and it runs well at that point now. May have been a motor-rotor orientation issue also. The rotor-collet turning and rotor-motor turning tricks are commonly used to remove fan vibrations. The bottom line is never accept a ducted fan with any vibration. I had to rebuild the nose on my beloved, best flying FW250 scratch build, due to a fan explosion in flight, which caused servo control loss. There was a very slight harmonic in the rpm range. I spent 3 hours of trial-and-error balancing on the next rotor, and have numerous flights on it.

I now also have the rotor removal technique developed, without having to remove the fan. Eflite had upgraded the rotor a while back, purposely so that folks could lock the rotor and loosen the collet nut, without breaking the rotor. This fan housing-rotor are quite strong, as I was a bit worried during the process. You have to tighten the collet nut firmly, or the rotor can come loose. For removal, I wedged a hard balsa stick in the fan to lock the rotor. The tweezers were used to turn and remove the collet, as it has a cross-drilled hole that the tweezer tips can fit into. Since collet compression collars always are stuck on the collet, the collet remains tight on the motor shaft, and will require prying off. The allen wrench is inserted in the space between the motor housing and the rotor, and then moved like a pry bar, using pliers. Several prys from different spots around the rotor, and the collet came loose.

I'm a really happy camper as of now, as the fan not only runs smoothly, but the sound of the overall setup is excellent. It doesn't have the high pitched small EDF whine, and sounds more like a larger turbine. It's fairly quiet also, with the ducting acting as a muffler I assume.
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