Demise of a Ringmaster...

[wwwarbird]

 We had a really great day out at Piston Popper field yesterday except for one, uh, small incident.
 
 Keith Sandberg was just working out the final bugs and trimming of the Ringmaster he and I picked up from the generous Lee Concannon last November. This was in anticipation of using it for a Ringmaster only competition that's coming up as part of the Polk City, IA contest this June. After a half dozen flights or so Keith was just homing in on the "sweet spots". The 'ol "Ring" was flying and turning very well, and the Fox .35 out front was churning along very happily in every attitude.
 On the last flight though, at about the 8'oclock position of an outside loop, the wingtips suddenly decided to touch each other. It was over in an instant, snap, clap, SMACK! 
 It's too bad about losing the plane but I have to admit, it was pretty darn funny to witness. Sorry Lee!

[Target]

Not enough spar!
Ouch!!

[david beazley]

You hate to see someone crash, but you really hate to miss one!

[John Cralley]

Ouch!!!

S-1 Ringmasters have a weak spot at the root of the outboard wing and are known for folding or shedding the wing especially in violent maneuvers. Extra reinforcement of the leading edge, trailing edge and the spar along with fairly hard balsa root sheeting will handle the problem. I have resorted to using a carbon fiber tube for the spar in my scratch built Ringmasters.

[Leester]

Oh well, stuff happens !! That RSM kit lasted a while.. guess you'll have to build another one !!

[Bob Reeves]

Happens when someone tries to save weight in the wrong places.

[Steve Scott]

Odd how that happens - I've lost every plane I've owned on that ill-fated 'last flight'.   

[Leester]

Nobody was trying to save weight anywhere  !! It was built as the kit showed.. Maybe you should know what your talking about before you spout off !!

[wwwarbird]

 Just to clarify, this failure had nothing to do with Leester's build, and I wasn't implying anything of the sort either. Just chalk this one up to an old design flaw and one of those s--t happens things. No big deal.

[Mike Griffin]

I have honestly lost count of the number of Ringmasters I have built over the years.  If I had to guess it would probably be around forty or fifty.  Some were with the slotted solid leading and trailing edge and some were with the more recent built up leading edge.  I gave quite a few of them away and some I flew until I crashed them. I even built some that I bought from Dee Rice and Pat.

I NEVER had the wings fold on any of them.  Lee Concannon is an excellent builder and knows what he is doing when it comes to building model airplanes. Sometimes things just happen you can't explain.

The weak point of the Ringmaster wing has always been the leading edge , not the spar.  The leading edge HAS to be properly reinforced and if you build the wing as Eric Rule specifies with his kit, the odds are 99 to 1 that the wing will withstand maneuvers.  Eric and I had a conversation some time back about the structural value of the spar in the Ringmaster wing and basically, there is none the way the wing was designed.  In fact, you could leave the spar out completely without risking anything.

If you strive for a 16 ounce Ringmaster, go ahead, just don't cheat on the leading edge.

Mike

[Brett Buck]

S-1 Ringmasters have a weak spot at the root of the outboard wing and are known for folding or shedding the wing especially in violent maneuvers.

  Absolutely, and it got a lot worse when we got better engines. Everyone is so clever, trying to save weight by using "good" wood, but the airplane was designed around using rock-hard wood the consistency of hickory,  not 4.5 lb indoor wood.
  
    This one broke in the usual spot, right at the end of the center-section sheeting. Put a Veco 19 and a 9-4 on that bad boy and it will fail even sooner! It needs reinforcement of the LE in the first open rib bay. Lots of people hollow it out - bad idea!

    Better spars will keep it together but thats less efficient in terms of weight than the LE.

    Brett

[Phil Krankowski]

Mike, Brett, Thanks for the good information.  A ringmaster is on my list.

Phil

[john e. holliday]

Well, my RSM Ringmaster built box stock with an LA 25 for power survived my first flight mess up when I hooked the lines wrong.   Had them crossed with another set.   Pulled the stooge line and immediately knew I was in trouble.   The poor Ringmaster started doing what it was supposed to do. I started big loops.  The third loop it went straight in.   Only damage was broken prop and my pride.   I tried twisting the wing and looking for cracks.  Even the tail surfaces stayed in place. Rolled up the now worthless lines and hooked up another set.   I must have at least a dozen flights on it now and it is the best Ringmaster I have.   

By the way when I say just one more flight, I now just roll up the lines.   

Also the original Sterling Ringmaster I am still flying after  a rebuild,  did not break the wing when the new guy flew it.   Just split the covering and popped the tail surfaces loose.   All my S-1's are MonoKoted  with Rustoleum for color on them.   Do a search and you will see them.