Upscale Quinstar build(s)

[neil_w]

If I'm understanding correctly, the BT-60 is just friction fit in there for now? If that is so, pull it out. Then grab a large dowel (1-2" Dia.), and wrap sand paper around it. Find the vertical center of each pentagonal panel, where the BT makes contact with them, and sand on that line. It should only take a little bit on each panel to relieve any stress.

That may work. I just want to be careful not to thin the pieces down too much, though, and compromise strength. Once I get the centering rings in there I'll get a better idea whether it is really too tight, and if so by how much. Once I try it I'll post back here; gotta go dig through my (somewhat limited) stock of centering rings.

 

[TangoJuliet]

It shouldn't take very much on each side to loosen the fit a bit, so there should be no fear of thinning them too much.

 

[Charles_McG]

I weighed my 29mm Blender for comparison. 150g. G40s make a great flight, but I know I've flown it smaller. I'll have to check my notes, but I think I've flown it on an f26. I can't recall if I've gone down into the teens.

 

[neil_w]

My Quinstar should come out around 5+ oz... I would think that would have to be ok on anything from a D12 on up.

 

[neil_w]

I found a centering ring and stuck in my BT60, and put it in my dry-fit frame. Or at least, I attempted it to. Indeed it was a bit too tight to fit comfortably in there. Before taking any corrective action, I needed to figure out exactly where the tightness was originating from. I half-figured it out and half-guessed, and once I identified the offending panel I saw that it might very well be held too far toward the center by a couple of slots that weren't quite wide enough. So, before breaking out the sandpaper, I tried whittling away those few trouble slots, and lo and behold: the BT60 now fits in snugly but in a satisfactory way.

Which means I'm ready to glue the frame together. Hopefully will start on that this Friday.

 

[Charles_McG]

So far, so good.

 

[K'Tesh]

More Photos!!!

 

[neil_w]

More Photos!!!

I'll try! It's hard to capture some of the fine fit issues I'm dealing with, but I agree some more visuals are called for.

 

[K'Tesh]

For mine, I've got to figure out how large I'm going to upscale it. I'm thinking of a non-flying upscale, just for the fun of it. My source of fruit boxes is getting the grapes that come with plywood boxes again, and I'm raiding their stock as fast as I can. Since the ply is too heavy (and weak) for rockets, I'm left with wood projects that can't fly.

 

[neil_w]

It'll keep you busy for a while if nothing else!

 

[neil_w]

I have longer to go on this than I thought. I dry fit everything in preparation for gluing, and then realized I hadn't sanded down the surface of all the pieces. Then I took a closer look and realized I've got some filling to do. There be gaps here:


In hindsight, I should have made the slots smaller, and then only opened them up gradually as needed for fit. Live and learn.

Anyway, while there's more than enough contact among the various pieces to insure I can glue the whole thing together securely, and some of those gaps will be covered by other pieces, I still don't want to leave them like that. So I need to figure out the best way to fill them enough so that I can glue the adjacent pieces together.

I could just stuff some balsa shims in there, although it seems like it might be excessive labor to cut-to-fit so many of them (I haven't counted how many I'd need, but it's probably around 10, plus or minus). It'd be plausible to fill the gaps with some sort of glue, but I don't want anything too heavy and that sort of gap-filling substance is not currently in my arsenal as far as I know.

Any suggestions out there?

 

[Charles_McG]

I did a lot of 5 minute epoxy filleting.

I also did a lot of hand trimming tonight.

 

[Charles_McG]

And motor tube and retainer finally on. A G79 Smokey Sam installed.

 

[neil_w]

Looks great! How did you end up doing the decals/striping?

 

[Charles_McG]

Automotive pin stripe.

 

[neil_w]

I sanded the faces of all the parts, and then re-assembled. There are so many places to put glue on this darn thing, I wasn't really sure where to start. I decided to start on the outer seams (towards the outer edges of the saucer), and then after it's all one solid piece, go work on the inner ones near the body tube. Here it is on my gluing rotisserie:

I keep the body tube in place for now to maintain proper positioning of all the pieces. Then I just started gluing. After a few I found my favorite place to glue (picture is from directly overhead):

There's lots of pausing to let the Titebond II dry. It's going to take a number of gluing sessions before I hit all the necessary places, and then there will be filleting. At some point I'll decide how to attack the gaps; I counted and there's only around 5, so it's not as bad as I first thought.

At least I can now say the frame is all one glued-together piece. So that's progress.

 

[Charles_McG]

I started with the five wedges. But I had cut the tabs and notches, so they really locked the whole thing together.

 

[neil_w]

I realized that I should be able to do all my glue joints in exactly 5 steps, each corresponding to 1/5 rotation of the assembly. In each position, I apply TBII to all the joints where gravity will keep the glue in place while drying. After 5 rotations I should have covered them all. Here are 7 glue joints drying in the first rotation.

I can't say there is any clever plan here, just putting glue where I see two pieces of wood touching. At the end, I'll decide how much filling and/or filleting I want to do... It'll be all cosmetic, so I'll probably get tired of it before I get too far.

In the meantime I am also papering the up side of all the balsa pieces (i.e., the sides you'll see most when painted). Those'll get attached only after all this silly gluing is done.

 

[Cabernut]

Sooo many fillets...

The ones you have are neat and clean though

 

[neil_w]

They won't look neat and clean after the TBII bubbles and shrinks down! I'll be doing some finishing fillets an/or CWF filling of the most visible ones at the end.

 

[Charles_McG]

I did them in bulk, too. I think it took me more rotations to get all of them - lots of joints - easy to miss some.

 

[JumpJet]

I wouldn't make your upscale a show model. Make it nice so at three feet away people will go OO-AHH. Flying is the best part of this design.


John Boren

 

[neil_w]

I wouldn't make your upscale a show model. Make it nice so at three feet away people will go OO-AHH. Flying is the best part of this design.

Ha, believe me, with my hand-cut pieces it won't be a show model.

Totally agree about the flying, my regular Quinstar is one of my favorites to fly for sure. I am hoping this one will be really nice on an F15-0.

 

[neil_w]

Turns out that these were the only two gaps that really needed filling:


So I cut a couple of slivers of 1/8" balsa and glued them in there, then covered with TBII:


I'll call that "good enough". Eventually the most visible bits will be completely encased in fillet, so they should look fine.

Started applying my "finishing fillets", with TB NRND. These go only over the most visible "exterior" seams.


I've almost given up on getting any of that glue through my pointy nozzle, so I just applied it with a toothpick and then smoothed it with my finger.

Since I'm almost completely glued up, I did a quick check on the fit of the top pieces:


Hmm, a bit loose and gappy. I could either re-make the top pentagon a bit larger, or else just fill the gaps with CWF at the end. I'll probably just do the latter, should take only a minute.

 

[neil_w]

One bajillion glue joints later, the frame is finished. The exterior seams looks decent after the Titebond NRND fillets, and the whole thing feels very solid... should not have any problem with an F15, and who knows maybe even something a little stronger. The balsa pieces (which are all the remaining pieces, not yet installed) could at some point become the weak link, but the papered 1/8" balsa with carefully oriented grain really ought to be fine, especially since the pieces are not very large, and they're very well supported.

Anyway.

Following the assembly sequence of the original Quinstar, I inserted the small pentagon piece into the top of the frame. I tried it in all 5 possible positions, and was relieved to find that in exactly *one* of the positions it was a very good fit. Glued it in, and then sanded the top with a sanding block to ensure as flat as possible a surface to glue the top pentagon piece.

Next came the top piece. I put a bit of weight on on it while drying...


And here it is, all finished. At some point later I'll put a nice layer of glue (probably 30 minute epoxy) on the inside of hole, to fortify it against the ejection blast.


I confirmed that my piece of BT60 with centering ring still slides smoothly into the center compartment. I should no longer have to worry about that.

 

[Charles_McG]

Coming along nicely. Still haven't mine into the air yet - but I have a CTI G79SS just waiting... Hoping for available_time*weather >= fatigue*work_undone on 2/25.

I sanded a bevel into the upper triangles so they fit nicely to the pentagon. That left them a touch short at the join to the lower/bigger pieces.

 

[neil_w]

I sanded a bevel into the upper triangles so they fit nicely to the pentagon. That left them a touch short at the join to the lower/bigger pieces.

That part is coming soon.

 

[neil_w]

Good grief this thing is a lot of work. I knew that going in, but it still keeps surprising me. So many pieces to prepare, and fit, and glue.

For the little shelf pieces that insert into the sides, I tried to be smart. In my regular Quinstar build, I found those pieces to be a bit small, and didn't really wedge tightly into the available space. So for this one I cut them too big to start, and planned to trim and sand to fit.

Here's one of them, laid on top of the frame. The pink circles show where the ends are too long; putting the piece in this way let me see and mark exactly how much I needed to trim off.


I cut the bulk off with a knife, and then sanded the rest of the way. Here are the results for one of the pieces:


Notice that the long exposed edge at the bottom almost exactly aligns with the holes in the frame at the left and right. That is also a result of trimming and sanding. So this actually worked out according to plan. Cool.

Here are the five pieces, papered and ready to go. Each piece is numbered and fit for a particular position in the model.


Gluing these in should be straightforward.

 

[Charles_McG]

Does yours , by itself, stand upright on two wings, axis parallel to the ground? Might make gluing and drying if two shelves at a time easier.

 

[neil_w]

I don't think so, but I just suspend it on a dowel through the middle (that's how I did the frame glue joints). Good idea for gluing the shelves, I actually didn't think of that.

Does yours stand up like that?