Old Wreck Becoming New Project.

[John Stiles]

I started rebuilding one of my old crashes yesterday. It was in several pieces, so there's really no good "before" pics. Its a plane I designed, and was really ugly anyway. Here's what I've done.....cut the trailing edges from the third ribs each side of center, and chopped the wingtips by a little over 1". Completely re-designed the stab and elevator, and shortened the fuse by 3". Rebuilt the firewall, I'm going away from the McCoy .19(type 21) that had resided there....to accept a motor I traded a friend out of; a Norvell Big Mig .15 made in Russia. Here's the new construction so far:  

[John Stiles]

Almost forgot, the new dimensions are WS=34" Length=22" I'm open to any suggestions and/or criticisms. Show no mercy! 

[BillLee]

Too late for now, but keep in mind on the next wing you build: the spar in the middle like you have it is about as worthless as anything you could do. Yes, I know the original Ringmaster had it that way, and it was just as wrong then as now. 

Regards,

Bill Lee

[John Stiles]

Yep, it does give away how long ago I actually first built the plane

[Brett Buck]

Too late for now, but keep in mind on the next wing you build: the spar in the middle like you have it is about as worthless as anything you could do. Yes, I know the original Ringmaster had it that way, and it was just as wrong then as now.  

   Agreed, but I would note that there is an even worse way to go - build it this way, except leave the spar out entirely! That's how the Firecat was designed.

  For years with period motors, the Ringmaster wing construction was fine. The LE was usually the consistency of oak, anyway. But when we started building them with OS15/20/25s, or Veco 19s, with 4" pitch props and "good" wood, they fly apart with alarming regularity. Couldn't generate much cornering load with a Fox, but replace it with a Veco 19 and a 10-4, it corners much better  - until the wing blows off.

     If I was going to build one, I would build it as light as possible everywhere else, and replace the spar with stacked carbon pushrod tubes. 3 deep out to the second open rib bay, then just a single one out to the tips.

     Anyone doesn't understand or believe that modern engines with low-pitched props make a huge difference should compare a Ringmaster with a Fox to a Ringmaster with a Veco 19 or OS20FP, or even a 15FP. With Fox, it's the same old barking dog it has been since 1951. With the Veco, it's not a great performer but you can at least fly it with minimal accommodation.

    In this case, with a McCoy 19, there's no need for concern. And it looks like a neat design. I would go in and hollow out the LE near the tips from about the second open bay to the tip. And scallop out the inner edge of the TE, cut a bunch of holes in the tips, ribs, etc to save as much weight as possible.

     Brett

[Douglas Ames]

Your elevator looks like it exceeds the area of the stab.
Might be a little flighty around neutral?
Neat design!... but I'd move the hinge line back some.

[John Stiles]

  Agreed, but I would note that there is an even worse way to go - build it this way, except leave the spar out entirely! That's how the Firecat was designed.

  For years with period motors, the Ringmaster wing construction was fine. The LE was usually the consistency of oak, anyway. But when we started building them with OS15/20/25s, or Veco 19s, with 4" pitch props and "good" wood, they fly apart with alarming regularity. Couldn't generate much cornering load with a Fox, but replace it with a Veco 19 and a 10-4, it corners much better  - until the wing blows off.

          Brett

I think I can relate to that......I put a K&B .40 on an Imperial Ringmaster once and the bellcrank tower broke out. There weren't enough pieces left to put back together.

[John Stiles]

      In this case, with a McCoy 19, there's no need for concern. And it looks like a neat design. I would go in and hollow out the LE near the tips from about the second open bay to the tip. And scallop out the inner edge of the TE, cut a bunch of holes in the tips, ribs, etc to save as much weight as possible.

     Brett

I'm gonna have a NV Big Mig .15 on it this time. I thought about the hole cutting and stuff, I'm still thinking about doing that.

[John Stiles]

Your elevator looks like it exceeds the area of the stab.
Might be a little flighty around neutral?
Neat design!... but I'd move the hinge line back some.

I'm going for the "flighty" this time.......I test ran the .15 and it really turns the RPMs......I'm extending my lines out to 70' if I can find the lines......I'm in the process of cutting trees around my circle for a new Nobler ARF I just finished......it's right at 50" WS with a .40 engine.

[Brett Buck]

I'm going for the "flighty" this time.......I test ran the .15 and it really turns the RPMs......I'm extending my lines out to 70' if I can find the lines..

   Norvel 15? Take it easy on the lightening, then. Lightening the last few rib bays are OK, the inner open bays (particularly the first open bay), definitely not. The usual spot for Ringmasters to fold is right at the inner edge of the first open bay. Pretty much where you would expect.

     Brett

BTW, I would suggest starting with a 9-4 APC, and then cut it down until is runs just a bit off of peak. That ought to keep it subsonic, at least.

[John Stiles]

Thanks Brett.....I'll take your suggestions into serious consideration......I don't want to splatter any more planes Thanks again.

[Howard Rush]

This conversation is alarming, because I just received a lovely Ringmaster kit made with light wood.

In the old days when we'd stuff our Ringmasters straight in on the nose, the trailing edges would separate in the middle, and the wings would pivot forward about the LE joint at the wing root.  The spar would then be worse than useless: it would pull the ribs apart.  We got the brilliant idea to put the spar in, but not glue it to the ribs.  That way it was merely useless.

[Brett Buck]

This conversation is alarming, because I just received a lovely Ringmaster kit made with light wood.

In the old days when we'd stuff our Ringmasters straight in on the nose, the trailing edges would separate in the middle, and the wings would pivot forward about the LE joint at the wing root.  The spar would then be worse than useless: it would pull the ribs apart.  We got the brilliant idea to put the spar in, but not glue it to the ribs.  That way it was merely useless.

    Well, I suggest a Fox 29. The instant stalls at half level flight speed will reduce the load nicely!  Try putting that airfoil into Javafoil, see how blue it gets at about 10 degrees.

      The danger area is the first open bay. If you only knew someone with the knowledge and experience with graphite construction methods, you could reinforce the leading edge, top and bottom, with a maybe 1/16 square graphite bar out to about the second open bay. The problem would be solved and you could slap on a 20FP with reasonable chance of success.

   David's was really great. Just minding his own business, doing his fifth outside round up at the Nut Tree Airport, and whack, off came the outboard wing, autorotating, right in front of me. I almost caught it. Then he just continued the loop and got it level. Funny thing is, even with only the inboard wing, it still flew about as well as the average Ringmaster!

      Brett

p.s. you know the Bart Klapinski leading edge joiner trick, right? That will keep the nose on it a little longer.

[Howard Rush]

I had a Fox .29 on a Ringmaster.  It fell into the circle, crashed on its nose, and the wings came forward.

No, what's the Bart trick?

[Brett Buck]

I had a Fox .29 on a Ringmaster.  It fell into the circle, crashed on its nose, and the wings came forward.

No, what's the Bart trick?

    I don't know if he invented it (I wish *I* had but, alas, imagination is lacking), but when joining the LE in the middle, it used a lozenge-shaped plywood joiner. Replace that with a "T"-shaped joiner, and have the "vertical" stroke of the T sticking out the front of the wing, like a tab.  Then cut a slot in the fuselage to accomodate it. Install the wing before the doublers  so the t goes into the slot, then apply the doublers over that. Ties the wing LE and the fuselage together, which is a critical problem with the original kit. I can sketch it sometime if that's not clear enough.

    Brett

[Howard Rush]

Quite clear, thank you. 

[Tom Niebuhr]

I don't know who started it but Tom Hampshire has been using the "T"-shaped joiner for at least 25 or 30 years.

[john e. holliday]

Every time I see post like this, it makes me wonder how I ever got a flight in with my Sterling Ringmaster.  Even the club I belonged used Ringmasters.  At that period of time the glues were Comet, Testors, Duco Household Cement and Ambroid.  No epoxies, automotive paint, no poly paints and no fiber glass.  We put the hottest engines available on them and flew.  The only time a wing gave up was when verticle landings were made.  For a design that was so bad it has lasted a long time and still getting people in the air.


PS:I like the rebuild.  jeh

[John Stiles]

Every time I see post like this, it makes me wonder how I ever got a flight in with my Sterling Ringmaster.  Even the club I belonged used Ringmasters.  At that period of time the glues were Comet, Testors, Duco Household Cement and Ambroid.  No epoxies, automotive paint, no poly paints and no fiber glass.  We put the hottest engines available on them and flew.  The only time a wing gave up was when verticle landings were made.  For a design that was so bad it has lasted a long time and still getting people in the air.


PS:I like the rebuild.  jeh

Thanks Doc, I've built upwards of 20 Ringmasters myself.......with the plywood stiffeners, and some "brushed into the BC box" epoxy........I seem to have survived even through some HB and OS engines! I guess I didn't practice the vertical landings enough, but became a pro at landing inverted