Baby Ringmaster build thread.

[JPvelo]

Started a brodak Baby Ringmaster today to be powered by a Tee Dee .051. Leaving the landing gear/grasshooks off as they just get in the way at my field. I know this may sound sacrilege to ringmaster fans but I will be changing the tailfeathers to something that better matches the outline of the wing.
In an effort to save weight I've elected to use titebond for the ply fuselage doublers in lieu of epoxy. Of course the hardwood motor mounts will still be epoxied into place.
Also toying with the idea of medium weight silkspan and dope for the wing. Any thoughts on how this will hold up on grass landings with no gear?

Jim

[RknRusty]

Silkspan won't last landing on grass near as well as modern polyester shrink-wrap. Pre-glue the doublers with Titebond, then sand the glue flat before applying the final coat to join them. I learned that from Ken Cook.

[pkrankow]

Clean grass, just fine. I have flown dope on silkspan without gear over grass in the past and the finish had reasonable durability. Of course a twig in the grass won't pop a film, but may put a tear in the silkspan. That said everything I have is covered in film anymore.


Phil

[JPvelo]

Silkspan won't last landing on grass near as well as modern polyester shrink-wrap. Pre-glue the doublers with Titebond, then sand the glue flat before applying the final coat to join them. I learned that from Ken Cook.

Too late, already glued. That sounds like a cool trick will try it next time. One thing I will definitely silkspan is the fuselage. Will use the lightweight that came with the kit and try for a glass smooth paint finish.

Jim

[RknRusty]

If you would, I'd like to read about the details of doing that silkspan on the fuse when you get to it. My Shoestring was covered with polyspan(I think) when it was originally built and I like it. He covered it with some sort of spackle to hide the weave.

[Cribbs74]

+1 on the silkspan fuse. I would love to see how that goes down.

Ron

[Ken Cook]

Dave Brown makes a product called Flex All. This product really elasticizes dope to the point it's like Monokote. Depending on the dope you choose to use, some dopes get to what I call the potato chip stage. This isn't old dope I'm referring about. If you don't build up enough clear coats, it will shatter in the open bays like in a cartwheel landing. The Flex All really worked for me. I can't tell you how many times at least until I found a better ignition clip that it would pop off and go right through the wing. I'm a big fan of Sig Lite Coat due to it having better fuel resistance to other brands and it has less of a tendency to warp small structures like a 1/2A wing. Ken

[JPvelo]

So here's how it looks:
https://i.imgur.com/XSv3jpv.jpg
Decided to go with 2-56 blind nuts and hide the engine to pretty her up a little.
https://i.imgur.com/RLwy2nv.jpg
https://i.imgur.com/GbokZpL.jpg
The stab/elevator is the same outline as the wing scaled down to about 45% in size, the area will be just shy of 25% of the wing area.
Haven't cut the vertical stab yet.
I am only going to silkspan the engine side up to the ply doubler, I don't want the engine case chewing into the covering. I will brush the doubler with two coats of thinned epoxy to fuel proof, I can sand that down to a nice finish.

Jim

[pkrankow]

Ain't a ringmaster anymore with those tail feathers!

Looking forward to the finished package.

Phil

[JPvelo]

Ain't a ringmaster anymore with those tail feathers!

Looking forward to the finished package.

Phil

Looking less like a ringmaster with every cut! Sacrilege, I know! I'm tempted to cut the leading edge instead of the trailing and make it a swept wing.

https://i.imgur.com/ALQVX1b.jpg

Jim

[Cribbs74]

Ain't a ringmaster anymore with those tail feathers!

Looking forward to the finished package.

Phil

Looking less like a ringmaster with every cut! Sacrilege, I know!  I'm tempted to cut the leading edge instead of the trailing and make it a swept wing.

https://i.imgur.com/ALQVX1b.jpg

Jim

Just tell everyone it's your design and no one will be the wiser. Looks good as all your models do.

[pkrankow]

Ain't a ringmaster anymore with those tail feathers!

Looking forward to the finished package.

Phil

Looking less like a ringmaster with every cut! Sacrilege, I know!  I'm tempted to cut the leading edge instead of the trailing and make it a swept wing.

https://i.imgur.com/ALQVX1b.jpg

Jim

WOW. Wild idea... except the bit that ringmasters tend to build nose heavy to begin with. If you had not assembled the fuse, and therefore were able to shorten the nose some during some pre-assemby balancing, I would be more on-board with this idea, but the wings getting swept back is going to make it a yard dart once power cuts. At least nose heavy flies once in the air, assuming enough power.

Actually I kinda like the idea quite a bit more than the tail feathers. Take out the rib ripper, change the wing, (use a biscuit to join the new LE halves, saw it into the LE and glue in place like the bigger versions use)

I'm nearly clueless where to put the lead outs though, other than the forward one exiting about the desired CG...

Phil

[JPvelo]

Silkspan cut, ready to apply basecoat dope. Wish me luck!
https://i.imgur.com/mPpYyKQ.jpg

Jim

[JPvelo]

Two base coats full strength, silkspan applied full strength.
First side done and trimmed.
https://i.imgur.com/TJCP0Il.jpg.
Second side done waiting for trim.
https://i.imgur.com/KQAtxce.jpg
Hanging in the tree to dry. July in Phoenix, should take about ten minutes.
https://i.imgur.com/9WiLP1d.jpg
So far more time consuming than difficult.

Jim

[JPvelo]

Two coats full strength dope, silkspan laid down with full strength dope, 7 or 8 coats thinned 50/50 with talc added for a filler:
https://i.imgur.com/8y0berL.jpg
Smooth and shiney as a babys butt! Will paint Wednesday afternoon.

Jim

[JPvelo]

Painted tonite. Finish came out shiny but I did all sanding along the length of the fuse with 400 and ended up with a "grain". Next time I will use a sanding block in both directions on the fuse and work down to a finer grit. Input/advice from anyone with experience sillkspaning a fuse is welcomed.
https://i.imgur.com/rOugnQr.jpg

I am very happy with how the silkspan filled gaps in the transition between parts.
https://i.imgur.com/oY5rHWo.jpg

All in all the best finish I've put on a model to date and the next one will be better. This is the first one that doesn't look like a piece of wood disguised as a model airplane.

Jim

[Cribbs74]

Looks good Jim, can't wait to see it finished.

Ron

[JPvelo]

This thing is coming together, I forgot how fast it goes when working from a kit. I found that the rib/leading edge fit lent itself to 1/32 sheeting:
https://i.imgur.com/UMqQRgd.jpg
Not the best photo, sorry.

Starting to look like an aeroplane:
https://i.imgur.com/fyja8Kb.jpg
https://i.imgur.com/jfvuJTN.jpg

Just waiting for a roll of ultracote to arrive at the hobby shop and I can finish up, hope to maiden on Thursday.

Jim

[RknRusty]

That's going to be a blast with a Tee Dee. You do nice work, Jim, I'm looking forward to seeing it fly.
Rusty

[Cribbs74]

Good choice on the TD. How do you plan on mounting the tank? Or are you going bladder?

[JPvelo]

Good choice on the TD. How do you plan on mounting the tank? Or are you going bladder?

Definitely going with a bladder. For me it's the easiest way to get consistent runs and easy starting.

Jim.

[JPvelo]

That's going to be a blast with a Tee Dee. You do nice work, Jim, I'm looking forward to seeing it fly.
Rusty

Thanks Rusty, if all goes well I should have video posted Thursday.

Jim

[JPvelo]

Still waiting on ultracoat so no maiden today. I did put the motor I built up for this plane on the Satan today and take it for a test run. Tee Dee .051 with the Venturi drilled to 9/64. Oh yeah... I like it alot!

Jim

[JPvelo]

Finished! Came out at 5.5oz
https://i.imgur.com/Hffh667.jpg
https://i.imgur.com/Xl5Fvxr.jpg
https://i.imgur.com/84cUC4Q.jpg
This thing is 1.3oz lighter than my Lil' Satan with less wing area. I think I have a rocket ship on my hands!

Jim

[RknRusty]

Finished! Came out at 5.5oz

This thing is 1.3oz lighter than my Lil' Satan with less wing area. I think I have a rocket ship on my hands!

Jim

Wow, that is light. You going to fly it today? It looks perfect, nice job.

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