1:3.5 Slingsby Sedbergh T21b Build (Chris Williams Design)

[Tango Juliet]

Thanks Jim. I'm glad to have you watching.

[Tango Juliet]

I got home from work late Wednesday evening, then promptly headed for the NARCA Aero Tow early Thursday morning arriving early afternoon. It was my first Aero Tow event, but it surely won't be my last. Weather the first couple of days could not have been better, with Saturday being a bit more challenging with Hurricane Nate headed toward the coast. It was decided that Sunday would be a washout, so most broke camp Saturday afternoon. I returned home about mid-day Sunday.

I usually spend Sunday afternoons off out at my local R/C field with Grandpa. We met at the field and surprisingly the winds weren't too bad at all, but neither of us brought anything to fly and nobody else showed up, so we left early. Yesterday (Monday) was a bit of a lazy day and I didn't spend any time in the shop. This morning I started to jig the Fuselage sides and get an idea of just how I want to go about assembling it.

As I noted earlier, the short kit Formers are 1/8" Ply, while the plans show them all as being built up with 1/64" Ply faces and 1/4" Square Spruce around their perimeter. As such, the Plywood Formers don't fit exactly as shown on the plan, so I have to make adjustments accordingly while still maintaining the proper dimensions to specific points such as wing strut fittings and wing pylon attachment points. Right now it's all loosely jigged on the bench and nothing is glued. I'll wait until my next week off to really tackle it. I go back to work tomorrow afternoon and I want to have 2-3 days off without interruption to ensure I can work slowly and methodically. I'm thinking I'll probably start with F5 and work fore and aft from there as that's the widest point of the Fuse.



No Bananas Wanted! Looking good so far.

[Swiss1]

Keep it up!

[lenb]

Congrats on the first aerotow!
Glad to see you digging right in.

[Tango Juliet]

Thank you. Let's be clear though, I still have not piloted a glider during tow.

[BStaley]

Very nice work so far! It's a big project so keep working on "mini-projects" and pretty soon you'll have quite a bit done. I have a "Petrel" waiting to be completed after I finish the TG-2. A fellow flier started it and lost interest so I ended up with it. No to be the "fly in the ointment" but you might want to think about the silver scheme-it's very nice looking but the silver might be hard to see when you get the bird up high. Just my 2 cents. I was raised in Mobile-we lived there until Brookley AFB was closed-ended up in Jax FL. Still have family there. Bill
-What would we do without a Dremel tool? I don't know how I got along for so long without one!

[Tango Juliet]

I have given that some thought, but at altitude they all go black anyway, so I'm not overly worried about it.

[Tango Juliet]

After pondering the situation of the Plywood Formers provided in the short kit versus the built-up versions indicated on the plans and how things would come together, I finally decided to build up F5 and F6 also. It just makes fitment easier in the end I think, as the vertical 1/4" Spruce sides are already a part of the Fuselage sides. As luck would have it, they turned out lighter also!




Do you ever get that feeling as your progressing along that something just isn't quite right? But at the moment, you just can't put your finger on it. Well, after taking a little break, I came back into the shop and looked closer at my plans and it jumped out at me. In my haste to make the new F5 and F6, I forgot to add some critical hardwood that the wing center section will get bolted to!


Easy enough to fix though. Just cut out an opening large enough to insert a 1/4" Plywood plug in F5 and F6. The area of the opening will never be seen as it's interior to the wing pylon.

[Tango Juliet]

Even though I probably spent 16-18 hours working on things in the shop this week, it just doesn't feel like I've got much to show for it. But a lot of that time was cutting, fitting, gluing, soldering, sanding, filing, painting, etc. It's small stuff, but it all takes so much time.

I cut, drilled, filed, primed, and painted the wing strut attachment points that protrude from the Fuselage sides. They're simply cut from 1/16" Aluminum.

I painted them first with an etching primer, then a grey paint. I'm wondering though if they might be 'too' soft?

I also did more work on the Rudder Pedals. They also got primed and painted, then I made some "bearing blocks" with 1/8" Ply and Balsa. The Left Pedals get attached to the top, back side of F2 and the Right Pedals get attached to the top, front side. When rigged, the pedals are all aligned horizontally as they hang.


And I did just a little more work on the Yokes/Sticks. This part takes a little more thought. I have the full size plans for it, but I think for the ease of making it all actuate with micro servos, I might use some artistic license in how I make and assemble it, but it will still look the part.


I'd have probably gotten just a little more done this week, but I also bought a new Radian XL 2.6m motor glider and I spent some time masking and painting it as well as updating the software on my Futaba 14SG that I bought two years ago and never took out of the box before this week!

That's all for now. I'll have more to show in two weeks.

[Cliff Evans]

You DO NOT need to make this lighter! I used 1/8 ply formers on both of mine without any problems.

[ARUP]

Good thing you put the hardwood in that empty spot! Just think... you will soon have a very cool sailplane flying about!

[Tango Juliet]

If I hadn't noticed it when I did, I surely would have realized it when I went to mount the wing center to the pylon, and I'd have been really PO'd then! As it was, it was much easier to fix now.

[gunny11]

Third scale, 1/16" soft aluminum? Maybe they should be from steel or G-10.
otherwise nice job.

[Tango Juliet]

Yeah, I may have to revisit this step before it's all said and done. I've got some G10 I could use.

[Swiss1]

TJ, I agree with Gunny, you can't make it to strong!

[ARUP]

TJ, how were the full scale fittings made? That's a good place to start. I like my old standard 'heat music wire hammer flat then drill and tap' fittings!

[Tango Juliet]

Michael, here are photos of the 1:1 strut attachment points.


And the wing attachment points...


I have some G10 material that I can use, but I thought I would improve the design just a bit more, borrowing slightly from your one-piece music wire method. I placed an order for more G10 that was long enough for me to run two continuous pieces from one side of the fuse to the other (13 1/8"), rather than four separate pieces for the left and right side, as the plan shows. They'll be bolted to the F5 Former front and rear, and that provides the gap between the tangs (which is also why the built up formers work better than the 1/8" Plywood formers in this instance).

[Dion Dunn]

All right! I'm glad to see you have started your build. The elevator horn set up is 'pin and fork'? The 'pin' drops into the 'fork' or slot on end of push rod? I think Art had this on his Cherokee thread or maybe Dion had it on his(?)

Not the best video, but you get the idea.

https://youtu.be/75aap1PE8qM

[Tango Juliet]

Yes, I fully understand it. The way I did it is just a variation of the same thing really, though mine is undoubtedly a bit heavier.

[Cliff Evans]

Here is my latest 1/3 scale T21 Weight 42Lbs!!! And flies just like the full size.

[Swiss1]

Nice stuff Cliff, that should give you some incentive TJ

Jeremy and Ben
SCCAAA TT TN

[Tango Juliet]

Another week off has just about passed. And again, not a lot to show for it. But, that's life sometimes. Here's a few images of what I did manage to work on.

I was able to get F4, F5, and F6 into place and glued. Laying the level across the top edge of the fuse sides helped to ensure that everything was remaining true.


I was able to finish the assembly of F2 with the Rudder Pedals and get those painted. Here is F2 in situ, but not yet glued into place. You can barely see F1 in front of it, being suspended by the upper and lower keel beams (which are also NOT glued into place yet).
As it sits in the above photo, the fuselage sides are too narrow to fit the F3 Instrument Panel, and oddly, there is no Lower F3 on the plan that would define the forward portion of the seats. When the portions of the fuse sides forward of F2 get pulled in toward F1, the sides bow outward between F2 and F4, then F3 fits as advertised.
F3 got paint also, as well as opened up to accommodate dial instruments from IFlyTailies. I'll have to hand-craft the vario. Then the Instrument Panel will get black paint before adding the instrument faces.


And I got just a small bit more work done to the Control Yokes, which will be attached to the, as of yet non-existent, Lower F3.

So there we are for another week.

[ARUP]

Pretty neat stuff!

[Asher Carmichael]

Looking good, TJ. I’m especially enjoying your detail work.

[Tango Juliet]

Thanks Asher. It's all the little details that eat up so much time, but it's kind of fun creating them. The real fun is going to be pulling the sides of the fuse inward to F1. I can just about manage it now without cracking anything, but I need two more hands to hold it in place while I'm also trying get glue where it's needed. I think the best way to manage it is to wet the sides and use a hot iron on them while finessing them into the bow. I may also need a large wood clamp. Fun, fun.

[Tango Juliet]

I got a little stumped this week. Where I need to pull the Fuselage sides in at the front to capture F1, the curve gets pretty tight and it seems that the sides are coming up a bit short of where they should be. It seems maybe that the plans didn't quite account for the curve eating up some of the length. The camera angle makes it look even worse than it is, but F1 is about 1/2" aft of where it should be, and if I squeeze the sides in to where they would meet F1, then it still needs to come back another 1/4-3/8".


What I'm considering is cutting a new, enlarged slightly, F1. Or... Pull the sides in to the current F1, then scab on more sheeting to the outside to get to the correct scale outline. Scabbing on more balsa sheeting wouldn't really be a bad idea I don't think either since I'll surely need to add nose weight for CG anyhow. It wouldn't look pretty, but unlike ARUP's sailplanes, this one doesn't have exposed plywood sheeting. It all gets covered with fabric (Solartex in this case).

Input from the masses is quite welcome here.

Not much else was done this week. Our club had its annual Toy Drive Fly In on Saturday, then several other club members had taken this week off from work, and Monday and Tuesday were too nice not to go out and do some flying. I finally got my Radian XL into the air after sorting out the programming on my Futaba 14SG.




I'm heading back to work this afternoon for the week. I hope everyone has a safe and enjoyable Thanksgiving Day here in the U.S., and that everyone around the world is able to enjoy some good modeling weather this weekend.

[ARUP]

I guess F2 is just in front of those 1-2-3 blocks? If so laminate 1/16 bass or ply strips on the inside of those longerons starting at F2 to reach forward to F1 or however long they need to be. Laminate them while maintaining that curve and even consider putting CF tow between laminates. When cured adjust the notches in F1 to fit the added thickness. Add some gussets strategically to maintain 'trueness' of the shape. Add filler balsa strips to the outside of the longerons then sand fair. Violin! done! That's how I see it being done from my arm chair.

[Tango Juliet]

Yes, that's F2 in front of the 1-2-3 blocks (the clamps are holding a piece of hardwood against it to keep it from bowing while I pulled the fuse sides in). Your idea is another alternative I had not considered. For now, my thinking is to just cut a new, larger F1. Then I'd only have to make the nose block larger, deeper. And the nose block is the perfect place to add needed weight. All of the interior from F3 to F1 gets fiberglassed (and probably some carbon veil as well) to really make it all rigid.