Ringmaster wing construction with molded LE

Ben's Wing End View

Practice picture

Here's some more pictures. Construction is light balsa, the molded LE is two sheets of 1/32 with medium weight silkspan glued in between.
The male mould is from a old RM LE. I attached it to my support with screws so I could adjust it, if it is not straight.

I like ferocious Phil C comments, see #4.


[photo not recovered: 22135.jpg]


[photo not recovered: 22143.jpg]


[photo not recovered: 22149.jpg]


[photo not recovered: 22150.jpg]


[photo not recovered: 22151.jpg]

Attachment #1, (jpg file)
Attachment #2, (jpg file)
Attachment #3, (jpg file)
Attachment #4, (jpg file)
Attachment #5, (jpg file)

Practice more and show how your jig works. Looks very interesting

I want to learn how to mold a LE like that. It is balsa, isn't it? Please give some tips or tell me where to get the knowledge.

Yes do tell Please

Warren Leadbeatter
Port Stephens - Australia
AUS-14782

http://www.clstunt.com/htdocs/dc/dcboard.php?az=show_topic&forum=103&topic_id=171633&mesg_id=171633&listing_type=search

A link to a balsa molding thread.
The process is very simple. Make a male mold out of almost anything stiff enough- balsa, bass, blue styrofoam. Add a backer layer so the molded balsa won't crack over the edge. Select some nice A grain balsa(the tricky part). Soak the balsa in water until floppy. Hold it on the mold with wrappings of gauze or strips of old sheets(Al Rabe). Let dry and trim to shape.

Since the Ringmaster wing gets a lot of its strength from the leading edge, how do you put back the strength?

Ya know, I quite enjoy applying new tricks to old model designs.

However, a molded leading edge on a Ringmaster wing is something that, well, there really is a law which says this kind of thing is totally unacceptable. Or at least there should be...

Dan

>Since the Ringmaster wing gets a lot of its strength from the
>leading edge, how do you put back the strength?


Ron B.
F4Fguy

Phil,

I don't know how Ben is doing it, but simply adding shear webbing between the ends of the LE molding from rib to rib will regain most of the beam stiffness. The cost in weight is minimal and the gain in strength significant.

Ron B.

Edit: New pics were added as I was typing. Just as expected!

Looks like the spar goes all the way from top to bottom. Do the ribs butt joint the spar front and back?


Giffy

Are the ribs cap-stripped? and if so, is that OT legal?

I went over to Ben's after work Friday, to help his computer learn to rework pics with IrfanView and post them on SSW. I'm afraid I've unleashed a monster!

The soft, light, ribs have firm 1/16" cap strips, look to be 3/32 wide, if that. As long as the net airfoil profile remains the same, it is legal. The rear spar is (from memory) thinner and higher, but not full depth. As long as it doesn't touch the covering, it's legal. Some of the molded LE's are webbed, and some are not, and are a bit bendy. So, just do it!

Ben's craftsmanship and productivity are surprising, impressive, and to be envied. I didn't take notes, but if there aren't at least a dozen Ringmasters in some stage of completion, I'd be surprised. Maybe 20? I did ask..."WHY?" He like 'em. Uh...O-kay! But why?

I found out the reason he was after a shaft extension for a .15FP. One of his planes is so light that the .15FP, mounted where the prop oughta be, would make it too nose heavy. Move the engine back, with a shaft extension, and the balance point is improved a bunch, with the basic engine and muffler much closer to the CG. As I recall, that model is not a Ringmaster, but a Super Clown. Main point is that he won't saw off the nose to move the engine back. Thus, I am not at all worried about his planes being illegal for OTS. [photo not recovered: sipcof.gif] Steve


Steve Helmick
Renton, Washington
USA

Thanks Steve you hopefully have answer a few of the forum members questions. You have seen my absence of typing skills so thanks again. Oh by the way all pictures are RM.

So teacher how do I get rid of my first pictures Box, which I mistakenly deleted.

Ben

>Are the ribs cap-stripped? and if so, is that OT legal?

Hi Larry, sure...if the capstrips are the same width as the original rib.
Tony

Ron B.
F4Fguy

Very nice Ben!

You really don't need the center ply of silkspan. It doesn't add much to the laminate when placed in the center. It may add some spanwise strength in tension, but thats about it,as it's on the neutral axis of the laminate. The best place, assuming you need it at all, would be the outside.

Ron B.

Judging from your pictures, you probably have at least several Ringmasters? What do you power with? Best guess would be that you are not a Fox/McCoy guy.