Ringmaster

[Gary Dowler]

My Ringmaster plans arrived today. Original S-1. Going to do a quick build on this before I get carried away with the PT-26.  Nothing fancy, just straight, light and clean.
Will pick up some more balsa tomorrow.  Would you recommend a 3" or 4" bellcrank? Think the plans show 3", stay with this?  OS 20 FP for power is planned. Hoping to end up under 30oz. Preferably under 28. Will see.

Gary

[Jim Hoffman]

A 3"  bellcrank  is fine.  I found that the distance between the Leading edge and the spar did not permit anything much bigger. 

It important to keep the controls slow. 

Install the pushrod in the inner most hole of the bellcrank.  Use a long control horn and insure the pushrod exit from the wing allows you to connect to the outer holes of the long horn

[James Holford]

A 3"  bellcrank  is fine.  I found that the distance between the Leading edge and the spar did not permit anything much bigger. 

It important to keep the controls slow. 

Install the pushrod in the inner most hole of the bellcrank.  Use a long control horn and insure the pushrod exit from the wing allows you to connect to the outer holes of the long horn

X2

Sent from my SAMSUNG-SM-G891A using Tapatalk

[Dane Martin]

And Jim Hoffman knows a thing or two about ringmasters!

[John Rist]

My Ringmaster plans arrived today. Original S-1. Going to do a quick build on this before I get carried away with the PT-26.  Nothing fancy, just straight, light and clean.
Will pick up some more balsa tomorrow.  Would you recommend a 3" or 4" bellcrank? Think the plans show 3", stay with this?  OS 20 FP for power is planned. Hoping to end up under 30oz. Preferably under 28. Will see.

Gary

If you want to keep it light use a built up leading edge.

[Gary Dowler]

Gentlemen, thanks much. I'll have to post some pics of this as it goes this will be a pretty quick build.

Gary

[john e. holliday]

Over on the Brotherhood of the Ring forum there are pics of how I built a super light leading edge .  I also did a trailing edge.  Yes it took time but I have plenty of it.


Well here are pics of leading edge I built for Nose Cone combat plane.  By the way the Ringmaster was done in one piece and has survived several nose first landings but I had to reglue back of fuselage.

[Tim Wescott]

A 3"  bellcrank  is fine.  I found that the distance between the Leading edge and the spar did not permit anything much bigger. 

It important to keep the controls slow. 

Install the pushrod in the inner most hole of the bellcrank.  Use a long control horn and insure the pushrod exit from the wing allows you to connect to the outer holes of the long horn

The advise that I got (after my wing was buttoned up!!) was to use a 3" bellcrank and drill a new hole 5/8" out from the center of the pivot point.  I wish I'd done so -- I either have a 3" Sig bellcrank in there or a copy of one out of phenolic.  Even with the pushrod on the inner hole, I ended up using an elevator horn that almost scrapes the ground.

[Tim Wescott]

If you want to keep it light use a built up leading edge.

You can go halfway in both work and weight by building up a LE.  Finding a good straight LE that'll fit -- or even a honkin' big stick of balsa to carve a LE out of -- is a chore.

These are old pictures that don't do a good job telling the story, but I built my LE up out of the lightest 1/4" balsa that I had.  It uses three sections, stripped out of 1/4" sheet.  You put the top & bottom on, then sand the front flat with your longest idiot board flat sanding board.  Then you glue on the front piece.  Finally, you carve & sand it to shape.  It's stood up well for me; I don't think I've broken that LE.

[Mike Griffin]

Gary this one of my Ultralite Ringmaster kits I put out last year.  I was 14 ounces as shown.  When I put the OS LA.25 and 3 oz tank on it, it came out at 24 ounces.

[Gary Dowler]

Ok, odd thing here.  Was just working on tracing out the patterns for the ribs, since I don't want to cut them out of the plan sheet.  That's when the calibrated eye caught something.  I work as a machinist making carbon aircraft brakes. I'm used to looking for very small variations in things.  I noticed something odd about the pattern for rib R7. Got to measuring and yep, it's drawn differently than all the rest. From the point of full airfoil thickness to the front end #7 is drawn a full 1/8" narrower than all the rest.
Going to have to average it between the outlines of ribs 6&8. Length is correct, but it's simply drawn skinny. Apparently wood isn't the only thing that can be sketchy in a Sterling product.

Gary

[Gary Dowler]

Gary this one of my Ultralite Ringmaster kits I put out last year.  I was 14 ounces as shown.  When I put the OS LA.25 and 3 oz tank on it, it came out at 24 ounces.

The picture doesn't show this real clearly, but it looks like the doublers are either very thin or missing outright. I am thinking of using 1/16 ply instead of 1/8.

[Dane Martin]

Ok, odd thing here.  Was just working on tracing out the patterns for the ribs, since I don't want to cut them out of the plan sheet.  That's when the calibrated eye caught something.  I work as a machinist making carbon aircraft brakes. I'm used to looking for very small variations in things.  I noticed something odd about the pattern for rib R7. Got to measuring and yep, it's drawn differently than all the rest. From the point of full airfoil thickness to the front end #7 is drawn a full 1/8" narrower than all the rest.
Going to have to average it between the outlines of ribs 6&8. Length is correct, but it's simply drawn skinny. Apparently wood isn't the only thing that can be sketchy in a Sterling product.

Gary

There is a set of plans floating around that have the corrected R7. I don't have my lap top here with me, or I'd look for it. But you are correct indeed. It's one of those esoteric jokes us ringmaster people know about.

[Dane Martin]

The picture doesn't show this real clearly, but it looks like the doublers are either very thin or missing outright. I am thinking of using 1/16 ply instead of 1/8.

That's a great idea.

[Randy Cuberly]

I wouldn't get too skimpy on the Ringmaster fuselage front end.  There isn't a lot of gluing area due to the fairly thin wing section and it's real easy to get a vibrator with skimpy fuselage construction.  I typically use 1/16 birch plywood (outside) laminated with 1/8 Light ply on both sides of the fuselage.  I've built three Ringmasters with LA25's all under 19 oz.   They all used very light hand carved balsa leading edges with carbon laminated inside.  (Yes that's a pain to make).  They really fly great at that weight especially here in Tucson.  (Hot with fairly high altitude).  I actually built at least 16 of the things in the 1950's because I used them for Combat.  Some of those were actually built from Sterling kits...They did not weigh 19 oz! 

Randy Cuberly

[Brett Buck]

I wouldn't get too skimpy on the Ringmaster fuselage front end.  There isn't a lot of gluing area due to the fairly thin wing section and it's real easy to get a vibrator with skimpy fuselage construction.  I typically use 1/16 birch plywood (outside) laminated with 1/8 Light ply on both sides of the fuselage.

     I don't think the light ply adds much in this situation, and it's more a matter of having something really strong to form a "skin" to spread the load, rather than needing the "skin" itself to be thicker. The "T" joiner will solve the cracking problem, you can make the thin doubler (1/16 at most - I would use 1/32, probably) larger and spread the load more for the same weight, which is a lot more effective than making it thicker.

  BTW, before everyone gets really super-clever with weight savings on the LE, be very careful about removing wood here:


because if you do, and use an engine that permits good maneuvering (15FP, 20/25FP, Veco 19, etc), you are in extreme danger of the wing folding. That's based on seeing about 1/2 a dozen to exactly that, including David, which broke off completely, just doing round loops. The built-up construction is fine and how most of us would do it, but I would be sorely tempted to run a stub spar (maybe 1/8 square spruce or very hard balsa from about 3 rib bays on one side to about 3 rib bays on the other side, glued right to the back side of the top and bottom LE sheets.

    Brett

[Randy Cuberly]

hmmm....Let's see now , you don't think making the front of the fuselage wider with a very stiff skin on the outside makes it any stiffer...better rethink that one Brett!
One of mine had carbon mat between the ply and light ply...couldn't tell any difference with that.  I agree that the ply tee helps here but is not a savour.

Also the increased gluing area at the wing fuse joint is very important.  I do agree that the leading edge should be strong but it can be made that way with very light wood laminated with carbon fiber.  I don't have any digitized photos of any of mine but do have some standard photos that I may be able to digitize if I can get the scanner section of my printer to work.  I had some problems the last time I tried.  It's old and is soon to be replaced!  I've done this and flown these airplanes many times at VSC.  Might even have won something if I could remember the OT pattern, but never took it very seriously and usually ended up putting something in the wrong place or my favorite trick "eliminate" the wingover!  I flew a Ringmaster built by a visitor to VSC that actually weighed 13 OZ with an FP 15 in it and it didn't break either...imagine.
Incidentally the Ringmaster in question of Davids probably had a thousand flights on it when it broke!  Just guessing of course but I believe it actually belonged to Ted Before David got it!
Incidentally the real problem with Ringmasters is trying to land the things unless you're David, or Ted, or Joe.  My record is 17 bounces but I've witnessed more by others!

Randy Cuberly

[Brett Buck]

Incidentally the Ringmaster in question of Davids probably had a thousand flights on it when it broke!  Just guessing of course but I believe it actually belonged to Ted Before David got it!

   No, it certainly did not belong to Ted, or have a lot of flights on it - maybe just the NWR and VSC. Ted, David, and I flew it one year at the regionals and it was brand new that weekend. That was a fun contest, I needed a caller so I had Ted talk to me on the headsets - which proved to be less than helpful as he also added comments like "that was TERRIBLE, FLY BETTER!" in the middle of the flight. 

    I think you are confusing it with Ted's cream monokote version, which David crashed (on two occasions as  recall). Never let David fly your Ringmaster, he's not going to cut it any breaks, it either goes to David standards, or it ends up in the ground. Both times with Ted's, it was because the engine quit, and it was unable to make a half a loop in 60 degrees with the engine not running.

   But the folds are a lot more widespread than just those guys, I see 2-3 a year, and I don't watch that many Ringmaster flights. BTW, it probably lasts a lot longer in Tucson, you simply can't put as much load on it in thin air.

Incidentally the real problem with Ringmasters is trying to land the things unless you're David, or Ted, or Joe.  My record is 17 bounces but I've witnessed more by others!

     Being Ted or David doesn't appear to help all that much when it comes to landings, it's always highly entertaining including the rare statistical anomaly it just lands once. Uncle Jimby, too. Joe seems to do OK.

     Brett

[dale gleason]

I'm no expert, but, if you ask me....since the approach to landing in OTS is not judged (per the rules), only the actual touchdown-  that gives one a little room to work to dissipate all lift in the wing right at touchdown. No lift equals no bounce (assuming a "horizontal" plane)...

 Caution- you can't have too much air under a Ringmaster when the lift is dissipated!

dg,
GMOTR

[Brett Buck]

I'm no expert, but, if you ask me....since the approach to landing in OTS is not judged (per the rules), only the actual touchdown-  that gives one a little room to work to dissipate all lift in the wing right at touchdown. No lift equals no bounce (assuming a "horizontal" plane)...

    Right you are, but that doesn't mean you can't give people a bad time about it. Jim has the same issue in Classic with his Feno, every once in a while, he manages to hit it perfectly - just often enough for him to never quite give up!

Caution- you can't have too much air under a Ringmaster when the lift is dissipated!

   You would think David would know that by now, but...

   Brett

[Randy Cuberly]

   

    I think you are confusing it with Ted's cream monokote version, which David crashed (on two occasions as  recall). Never let David fly your Ringmaster, he's not going to cut it any breaks, it either goes to David standards, or it ends up in the ground. Both times with Ted's, it was because the engine quit, and it was unable to make a half a loop in 60 degrees with the engine not running.

   Brett

  Yes You're probably right.  I was probably confused because it LOOKED like it had a thousand flights on it!  Poor thing looked very used and abused.  David by the way flew it very, very, well in "Classic" of all things and placed very respectably with it as I recall!

I think I finished about 12 in classic that year with nearly 80 entries! (Not with a Ringmaster, with a Nobler) Those times are long gone!

Fun to think back about them however!

I also remember judging Classic one year when there was 60 entries and one day of flying classic!  Never, Never again!  About 12 hours in the hot sun and eyes that couldn't tell a square from a round after about 10 hours! 
two circles two flights.   Interesting thing about judging at VSC is that you see a flight by an intermediate level flier with a barely recognizable pattern and next up is Ted Fancher, or Bill Werwage...not the best way to judge!

Can't imagine doing that at the worlds like they apparently did this year!...Crazy and absolutely not necessary for a competition of that caliber!  At VSC we simply got unexpectedly swamped!  That was probably VSC 3 or 4...Not sure!  They changed the format to 5 days after that!

Randy Cuberly


 
 

[Randy Cuberly]

I'm no expert, but, if you ask me....since the approach to landing in OTS is not judged (per the rules), only the actual touchdown-  that gives one a little room to work to dissipate all lift in the wing right at touchdown. No lift equals no bounce (assuming a "horizontal" plane)...

 Caution- you can't have too much air under a Ringmaster when the lift is dissipated!

dg,
GMOTR

Wow Dale...that bring back memories of Combat in Kansas City in the early 1950's , except we never used landing gear...

Randy Cuberly

[Brett Buck]

Can't imagine doing that at the worlds like they apparently did this year!...Crazy and absolutely not necessary for a competition of that caliber!  At VSC we simply got unexpectedly swamped!  That was probably VSC 3 or 4...Not sure!  They changed the format to 5 days after that!

   The last time I did something like that was probably in 2016, when I judged classic at the NATS, where I think it was around 50. I was doing mostly OK all the way to the end, but it was a push and the orange Gatorade was flowing very freely, but not coming out in the conventional manner.

     Then immediately afterwards, one of my cyber-stalkers from Stunthangar accosted me in real life about some absurd "gotcha" he thought he had on me - which proved he not only knows absolutely nothing about what he is talking about, but also cannot follow a simple conversation. So I was more than a little grouchy and for about 30 seconds, he got my goat, probably the first time at a NATs.

     Brett

[Mike Griffin]

The picture doesn't show this real clearly, but it looks like the doublers are either very thin or missing outright. I am thinking of using 1/16 ply instead of 1/8.

Gary the doublers on this plane are 1/16th. 

Mike

[dale gleason]

I've tried in vain to locate the photo of aerial demolition that occurred at a Houston Ringmaster Roundup- testimony to a weak center section induced by the quest for that super-light RM.  At least six, maybe more, Ringmasters folded their wings in flight that day. Some flew on and some didn't. At my behest, a young tyro tried a half-wing loop, usually an easy maneuver. He failed, such that the plane endured two insults in one flight.  Later, a photograph was shot with numerous smiling "pilots" among the stacked Ringmaster debris.

Why were we laughing? 

I'll keep looking,

dg

Note: There was a singular goal for all the Ringmaster hullaballoo that began at one of those VSCs, and I think it was very well met.
Namely, today, there's not a person on the planet who doesn't know who Mr. Matt Kania was!!

[GERALD WIMMER]

Hello
 Interesting post as me and my two sons are building Ringmasters for the October Ringmaster-athon but will use solid LE so they are easier to glue back together when they crash them (more gluing area).
Basing our build on a very early kit which we are coping and it has a two 21" pieces of LE with 1/8 ply joiner and center reinforcement. Perhaps this may be redundant if you make the wing by joining just short of the LE inboard tip (a 36 + 6"=42 span) ? Presume they used a two 21" LE's  to save on the kit box size .
Or should I still reinforce the LE center ?
We trying to make durable stunt trainers that will get bashed by my 9 and 11 year old but want them also to be able to enter pre-1970 classic stunt here in NZ
Stirling kits like the Yak 9 and the Goldberg Shoe-String had glue together and sweep LE's with the same style of joiner

Regards Gerald
 

[richardm]

Hi Gerald

I have a spare leading edge set from a kit I was given and are not that far away.

And it is lighter than a genuine part 

[Mike Griffin]

     I don't think the light ply adds much in this situation, and it's more a matter of having something really strong to form a "skin" to spread the load, rather than needing the "skin" itself to be thicker. The "T" joiner will solve the cracking problem, you can make the thin doubler (1/16 at most - I would use 1/32, probably) larger and spread the load more for the same weight, which is a lot more effective than making it thicker.

  BTW, before everyone gets really super-clever with weight savings on the LE, be very careful about removing wood here:


because if you do, and use an engine that permits good maneuvering (15FP, 20/25FP, Veco 19, etc), you are in extreme danger of the wing folding. That's based on seeing about 1/2 a dozen to exactly that, including David, which broke off completely, just doing round loops. The built-up construction is fine and how most of us would do it, but I would be sorely tempted to run a stub spar (maybe 1/8 square spruce or very hard balsa from about 3 rib bays on one side to about 3 rib bays on the other side, glued right to the back side of the top and bottom LE sheets.

    Brett

All very good points Brett.  Just for everyones information, the leading edge of the RSM Ringmaster is built up and utilizes 6 piece construction.  The back face of the leading edge is balsa backed up with thin plywood the entire length of the wing.  As I stated on another thread somewhere on here, I was building for other people at one time and I have lost count but probably have built at least 30 S1 Ringmasters over the past years, all from RSM kits and I have never had one of mine (or anyone else's as far as I know) that the wing folded.
 or broke off.

Mike

[GERALD WIMMER]

Hi Gerald

I have a spare leading edge set from a kit I was given and are not that far away.

And it is lighter than a genuine part 

Hello Richard
That sounds a nice tasty offer!
I will try message you
Good to hear you are still following the control line world
Regards Gerald

[Randy Cuberly]

I think a reinforcement in the center of the leading edge on the Ringmaster is important because the leading edge caries some of the flight loads.  In a typical more modern wing construction there are two spars top and bottom near the center of gravity and center of lift of the wing.  These spars carry the primary flight loads so the actual strength of the leading edge is much less important.  However in the case of the Ringmaster wing these spars are notable by their absence and this means that the flight loads will be transferred to the leading edge, trailing edge and center planking.  Therefore there will be significant load on the center of the leading edge and should probably have reinforcement with at least 1/16 thick plywood as a suggestion for about 3 inches or more of the center of the leading edge!  If you get the opportunity to look at a crashed or broken Ringmaster you will notice the leading edge broken exactly at the outside edge of that center reinforcement piece.  Without the reinforcement piece it would likely be in the center and will take significantly less load to break it!

Randy Cuberly

[Dan McEntee]

   If you are scratch building a Ringmaster and using pre-shaped leading edge stock like the original kit, you will need two pieces to make up the entire length of the leading edge. The secret here is to make the splice outboard of the center of the wing, where ever you have to make it. That way you have no splice at the center, and by adding the re-enforcing piece like the kit has, you will have a stronger wing center section. This is mainly for taking landing and dorking abuse. Like Brett, I have seen some of the other after market kit wings have some sort of issue for what ever reason  The pre-shaped leading edge stock from SIG has been looking pretty good  lately and I usually pick up a piece or two if it is the balsa rack just for later uses and needs. Not real cheap but does speed things up some times. I have stock, kt built Ringmasters but by other people and they are all under 30 ounces. I have a Brodak ARF Ringmaster with a LA.25 on it and it weighs in at 29 ounces I think. All fly well enough for the OTS pattern. They don't have to be feather lite to be able to fly well, just built straight and ballanced right, and controls set up properly.
  Type at you later,
   Dan McEntee

[Brett Buck]

Like Brett, I have seen some of the other after market kit wings have some sort of issue for what ever reason 

     I have seen then fail from kit parts, too - when someone decided to hollow out the LE wood to save weight, or scratch built exactly like the originals, but with 4 lb-wood. Clap!  Hollowing it out is a good way to save weight, the kit LE wood was frequently the consistency and density of oak. But don't hollow it out in the in the area I pointed to! And even further out, preferably make the walls pretty thick and let it get thinner towards the tips.

     Brett

[Gary Dowler]

Since weight is important, and since I'm building this by sourcing all my own wood (only have plans), I am making sort of a hybridization LE.  The LE material has the same nose radius as the plan calls for, but instead of 1" deep front to back it's only 1/2". The ribs will be extended 1/2" forward to accommodate this. This should have the same weight saving as the built up LE, without the extra work and associated time loss. So long as I have a satisfactory ply reinforcement at the center, and perhaps a extra spar across the inner 4 ribs, strength should be adequate for decent survivability.

Gary

[Brett Buck]

Since weight is important, and since I'm building this by sourcing all my own wood (only have plans), I am making sort of a hybridization LE.  The LE material has the same nose radius as the plan calls for, but instead of 1" deep front to back it's only 1/2". The ribs will be extended 1/2" forward to accommodate this. This should have the same weight saving as the built up LE, without the extra work and associated time loss. So long as I have a satisfactory ply reinforcement at the center, and perhaps a extra spar across the inner 4 ribs, strength should be adequate for decent survivability.

    Oh boy, that sequence of decisions seems pretty familiar. I would apply a *strong* spar right behind the LE wood, top and bottom at the surface of the wing, spruce or even graphite. Maybe about quarter span on either side.

  Brett

[Randy Cuberly]

Ya know...I hate to say this and I don't mean to pick on anyone but some folks just aren't paying attention!

The leading edge strength is very important because the Ringmaster has no real load carrying spars as in a C-Tube or D-Tube wing construction.  The load of flight as well as impact is carried in the leading edge trailing edge and center planking.   Those loads are strongest at the center of the wing near the fuselage.  Weaken any of those load carrying members and it is certain to fail...in fact even the stock setup often fails!

Don't be lulled into believing that the little spar buried in the aft center of the wing carries any real load...it can't at that location!  It is really just there (I guess) to help locate the ribs during construction.  At least I can't imagine any other use for it!

Randy Cuberly

[Tim Wescott]

The LE material has the same nose radius as the plan calls for, but instead of 1" deep front to back it's only 1/2".

I think you'll end up unhappy with that.  As Randy points out, the thing they call a "spar" is really just decoration -- the strength is in the LE, and to a much lesser extent, the TE.  The reason that the super-light Ringmasters with the hollow leading edges work is because in a structure like that, most of the load is carried in the outer skin anyway.  Make the LE hollow, and you're throwing away the part that isn't contributing to the strength.

However, the breaking strength of a member like that goes (very roughly -- it's complicated) as the size cubed.  That's why race car frames are made of tubing and not rebar.  Whack stuff off of the outside of the member, and you're taking away wood that's actually contributing to the strength and stiffness.

[Gary Dowler]

Message received and understood.  The thinner LE will not be used.  I hadn't understood the nature of how that wing distributes the loads, but what I am hearing is making sense.  Unfortunately while I want to build light, ultralite requires a built up LE that I have never tried and don't have time to learn to do on this one.  So I guess Im going to get proper LE material and go that route, just saving weight by picking the lightest wood I can get, which is the plan for the whole thing in general.

[Randy Cuberly]

I would reiterate what some folks here have said in that building the lightest possible Ringmaster might be good for some applications it is certainly not necessary for Old Time Stunt.
Earlier I mentioned building 18 and 19 oz Ringmasters but those were built for a special purpose not OT Stunt (even if they were used for that several times they were not ideal for it).  A Ringmaster with an LA25 will be a great flier in the 26 OZ range, and far less fragile.  I built mine to prove to someone that a Ringmaster could be built and trimmed to fly tight corners without stalling.  If you want to do that then it needs to be light and trimmed fairly tail heavy with severely limited control travel and very slow controls.

Most people would not be happy trying to fly a Ringmaster trimmed like that unless you can fly like Joe Gilbert, or David Fitzgerald!  It's possible to fly the modern pattern with fairly tight corners without stalling with such a critter but it isn't easy.

Randy Cuberly

[Gary Dowler]

Thank you, Randy!  I'm aiming for under 30, hopefully 28.......  should be do able.  And yes, survivability is somewhat important.  Just today I biffed my Shoestring Stunter with yet another inverted landing. In front of Mark Scarbourough who had come out to offer help. (I had tried making a change to my handle yesterday, but never got it in the air. Then today in my haste to get going I forgot to undo said change.........  the result in flight was pronounced bias to go up, which is down when inverted....  to his credit Mark didn't laugh too much).

Gary

[Tim Wescott]

Message received and understood.  The thinner LE will not be used.  I hadn't understood the nature of how that wing distributes the loads, but what I am hearing is making sense.  Unfortunately while I want to build light, ultralite requires a built up LE that I have never tried and don't have time to learn to do on this one.  So I guess Im going to get proper LE material and go that route, just saving weight by picking the lightest wood I can get, which is the plan for the whole thing in general.

I think you'll have trouble finding decent LE material -- you need a big straight stick; the more it's warped the worse your wing will be.  That's why I built mine the way I did -- I felt it was a good compromise between light, straight, easy material availability, and ease of building (it's easier than a traditional wing with an itty bitty LE and LE sheeting).

[Brett Buck]

Thank you, Randy!  I'm aiming for under 30, hopefully 28.......  should be do able.  And yes, survivability is somewhat important.  Just today I biffed my Shoestring Stunter with yet another inverted landing. In front of Mark Scarbourough who had come out to offer help. (I had tried making a change to my handle yesterday, but never got it in the air. Then today in my haste to get going I forgot to undo said change.........  the result in flight was pronounced bias to go up, which is down when inverted....  to his credit Mark didn't laugh too much).

   Crash survivability is another issue, and adding weight to survive crashes is contraindicated.

   However, super-light is not necessary for decent performance. The entire small--engine experiment was triggered (after decades of what should have been obvious signs pointing to it, that we somehow managed to ignore or disregard) by David and I helping a gentleman flying a Ringmaster, from a kit and with a full opaque paint job, certainly over 30 ounces and probably more like 35 - with a 15FP. It flew really good, by far the best-flying Ringmaster that we had ever flown and far beyond the average. That with no consideration at all for weight-saving, just a correct engine that holds the speed in the corners, and, more importantly, getting the control rates down so it didn't instantly stall at any time you touched the controls. I have seen models that were half the weight of this example either come apart, or not fly as well, even with good engines.

      I am very concerned with your structural modifications in terms of staying together for flight loads. I have seen very similar thought processes, arrangements, and schemes come to grief many times. You need to reinforce the leading edge substantially, near the root to at least about the 3rd rib on each side, and for sure where the center-section sheeting ends. If not, the LE is very likely to fail where my arrows are pointing. Don't take it from me, ask the guys taking pictures of a stack/pile of folded Ringmasters.

     Of course, like most of us, you can do experiments and learn on your own, but I think that particular growth experience can be avoided.

     Brett

[john e. holliday]

When first built my RSM kit of the Ringmaster was the lightest of the fleet  Yesterday I finished putting it back into one piece and the wing has stayed together on each and every mishap.   First mishap was pilot error on launch.  The rest were engine failures at inopportune times.   It is ready to fly again.  By the way I have the aluminum gear inserted into fuselage like some of my racing planes.

This is what it looked like before first flights.

[Gary Dowler]

Brett, my early ramblings and ideas not withstanding, I'm more than inclined to follow the guidance of those more experienced.  I don't mind keeping it light, light is good,  but flight quality is primary. My early thinking was that light was synonymous with flight quality. I'm figuring out from the various responses here that there is no absolute correlation between weight and flight quality.
My built got set back a week yesterday when I, again, managed to "land" my Shoestring Stunter in an inverted manner. (Issue with handle changes as mentioned above).  Need to get this back in service to continue the supervised flights I have started with Mark. First time since about 83 that I've had someone to watch me fly and offer advice.
I'm paying attention to every post you guys make. Your words are not falling on deaf ears.

Gary

[Gary Dowler]

In reading your responses I have a engine question.  Power wise my OS FP20 on my Shoestring Stunter is every bit the equal of my Fox 35 stunt, perhaps a little more. It might even be a little more than needed.  I had thought about transfering this engine to the Ringmaster given the overall similarity of the two ships.  Then Brett goes and mentions a Ringmaster flying very well on a FP15 for power.  I assume the 15 might save an ounce or two over the 20, and if the all up weight is around say 30, would this be a better fit?

Thoughts and opinions?

Gary

[Tim Wescott]

If I had a 15LA I'd try it on a Ringmaster.  I might make sure I could change back to a 20FP, though.

[john e. holliday]

That is why I use aluminum pads to mount engine to and then mount the pads to the plane.  Look close and you can see the pads on my Ringmaster.

[Gary Dowler]

That is why I use aluminum pads to mount engine to and then mount the pads to the plane.  Look close and you can see the pads on my Ringmaster.

For some reason I can't get the pic to open. I'd like to see how you arranged this mount.

Gary

[john e. holliday]

Basically I have aluminum pads  cut length so the bolts that go through/ in the fuselage clear the engine lugs.   The pads are bolted to the engine.  Early ones I drilled and tapped the pads for the engine.  Now I use flat head bolts through the pads with lock nuts on top of engine lugs.   The first engine is what sets the holes for the pads.  The pads on later engines for the plane is marked and drilled to match the plane.  Guess I will take some time to make a detailed pictoral.  But the pads on the DOC Special are done this way.  It now has an LA 46 in place of the Brodak 40.

By the way the muffler on the Brodak 40 is J-B welded in place as the ears on the engine are broken out.

[Gary Dowler]

Thank you,John. That explains it perfectly.

Gary

[Tim Wescott]

...  Early ones I drilled and tapped the pads for the engine.  Now I use flat head bolts through the pads with lock nuts on top of engine lugs.   ...

That's what I'm doing these days, except that I'm still in the drill and tap phase.  Maybe cuz I'm younger?