SZD- 48 Jantar Standard 2 scratch build?

[SteveNeill]

I have been looking at a number of possible builds for me. It's been awhile since I've made a fiberglass fuse from scratch but I have done plenty in the past. But rather then make a plug and fiberglass epoxy molds and produce a composite fuse, considering doing something I did once that worked out very well for a one off. I don't want to make kits anymore, I've done that.

What I did was wire cut blue foam using model ply templates both outside and inside of the fuse and glassed it with West Systems epoxy. This has worked out very well in the past with 90mm sized EDF jets. But what I'm planning here has not been done (to my knowledge) for a third scale plane.

I wanted to do a sailplane with a less complex wing then a Duo Discus or ASK 21. The wing for the Jantar can be easily wire cut in white foam, sheeted in balsa and glassed. I've done this many times but at 1/3rd scale for the Jantar I would be 195.6 inches and a fuse of 90 inches.

I ask you more experienced 1/3 scale builders, would it be more practical to go with a 1/4 scale build using this style of building or just go for 3rd scale and see how it rides?

It's a beautiful older design and I really like the looks of the plane. If I do build it at 3rd scale it would be my first.

So far I have found plans that I can clean up and enlarge. A source for blue foam and I have several bows for wire cutting.

[lenb]

Having flown a 40% Jantar as well as a smaller 4m version I can tell you they both flew very well. The simple and straight wing platform makes for an easier build, so that right there is a reason for choosing the design.
I'm also a sucker for any two seat sailplane, I just thing they look great, and with the longer fuse it makes the model larger at the typical 1/4, 1/3 or 40% ( 1/2.5 ) scales.

Good choice, now on with the build......

Len

[Tom]

Working on a project like that right now.......

[SteveNeill]

Len and Tom, thanks so much for the support and encouragement on this. So we go with third scale then. And Tom if I may ask what scale are you building and what is the bird?

So for Christmas present to myself I'm off to Burbank to here:https://foammart.com/product/square-edge/ not unless there's another option I have searched all over my local area and even Lowes doesn't carry it anymore. I have been buying foam products for years from Foam Mart for my movie work and personal projects.

I need to get to the computer and clean up these low resolution plans and enlargements of the formers which were the only thing I could find on the net for the Jantar. I've worked with worse. Lucky for me I own a studio full of computers with all the software needed. One of the things we do at SNG is after effects and CGI. So I'm covered with everything from the complete Adobe suite to 3D modeling building software.

With the holidays and some client work still to finish it will be slow but I will get stuff done. In January I should be able to get the old feather cut bow out and start cutting sections. Maybe sooner because I'm chomping at the bit.

For the wings I'll use white foam and sheets and glass.

Glad to hear the plane flies so well. That's what makes it all worthwhile.

[Tom]

And Tom if I may ask what scale are you building and what is the bird?

It’s a Arcus.......wing span is 4 meters.....full size is 20 meters.....so that makes the model 1/5 scale.
The construction method will work at any scale.....previously I built a Duo Discus with 36” span wings as a “test” which flew just fine until it met its demise behind one of Len’s tugs......caught a wing tip on take off and that was it! One day I hope to use the method on a 40% airframe....

[SteveNeill]

Sorry to hear that. 40% will be really something. I will look forward to that.

[SteveNeill]

Meanwhile I have been spending time on the computer in Illustrator cleaning up and printing out templates for the formers. My plan is to cut out the formers from MDF on the scroll saw and harden the edges with thin CA and lightly sand smooth afterwards the surface smooth enough for the cutting wire to glide over. I have done this successfully in the past and it saves a bunch of money over using model ply.

[SteveNeill]

It begins. First off to Lowes. I found a large sheet of marker board for 10 dollars. A sheet of model ply would have been a lot more than 10 dollars and I have more than I need for all the templates. The nice thing about this stuff is the white side for marking is easily cleaned off with alcohol so an Elmer's glue stick works good for holding down the printed formers and once cut you can easily remove and clean off the glue. It's easy to cut too. So you can be very precise.

I dug out my old Sears Craftsman scroll saw. Haven't used it in years but it still works well and did a good job of cutting two test templates. After they were cut I cleaned them up, lightly sanded the edges smooth and hardened them with some medium CA. Once the CA dries I sanded again. This made the edge very hard and slick for the wire to travel over. I have even done this with just cardboard for smaller scratch built foamies.

Tomorrow I pick up my large sheet of 4 inch thick blue foam but before I do any cutting I have to make up today the profile of the fuse and the station points for the templates. Nice to be doing this again after more than 10 years of dormancy. The movie business has a way of taking over every moment of your life at times. Something I don't miss but building planes I sure have.

[SteveNeill]

This is going to be a nice size. 90 inch fuse.

[SteveNeill]

What is my best source for a 1/3rd scale retract for this plane? Thanks.

[Tom]

What is my best source for a 1/3rd scale retract for this plane? Thanks.

Build your own......I have a drawing if you want.

[SteveNeill]

Tom I thought about that. I would be interested in seeing your drawing. Thank you.

[Tom]

Tom I thought about that. I would be interested in seeing your drawing. Thank you.

PM me your email......I’ll send it to you....

[SteveNeill]

Thank you Tom.

[ARUP]

Are you going to cut the foam blanks to build the fuselage then add the wing fillets or hot wire and glue everything together with all the 'lumps and bumps' in one go?