Ringmaster engine Q

Hi,
So, what's the engine of choice for a Ringmaster (~42" span)? Here's what I'm looking for:
- not finicky (starts reliably, runs OK)
- strong enough to do everything - eventually
- fairly quiet (read: muffled)

I'm likely to either repair/recover a really old (1957?) plane or scratch build one using the old one as a pattern. I've plans and scratchbuilt a couple of sailplanes before, and the structural part doesn't seem too difficult. Actually, it looks different enough from what I'm used to that it seems like fun.

I'm thinking that a strong-ish .15 or a .19 might be the engine of choice. OK, so there aren't a lot of .19s around. Maybe a Fox or OS 25?

Thanks in advance...

>Hi,
>So, what's the engine of choice for a Ringmaster (~42"
>span)? Here's what I'm looking for:
>- not finicky (starts reliably, runs OK)
>- strong enough to do everything - eventually
>- fairly quiet (read: muffled)
>
>I'm likely to either repair/recover a really old (1957?)
>plane or scratch build one using the old one as a pattern.
>I've plans and scratchbuilt a couple of sailplanes before,
>and the structural part doesn't seem too difficult.
>Actually, it looks different enough from what I'm used to
>that it seems like fun.
>
>I'm thinking that a strong-ish .15 or a .19 might be the
>engine of choice. OK, so there aren't a lot of .19s around.
> Maybe a Fox or OS 25?
>
>Thanks in advance...

I had a G21 35 Supertigre on pressure on the last one I had in 1973-74

One really nice light one that I am aware of flies well on an old Veco 19. Anything from an OS FP25 or LA 25, Fox 35, OS 26 four stroke for a few thoughts.

Yeah, but what fuel? I mean, high nitro with that combination would be overkill, right?

And le'me guess - after all of the fussing with crankcase pressure, special hand-carved props, streamlined wheels... It was still a Ringmaster, right?

>
>I had a G21 35 Supertigre on pressure on the last one I had
>in 1973-74

Ha, Ha! Yeah, and you created some monsters among those who saw it fly.

Hi....I have an ASP 36 on a Flite Streak, which is very similar to the Ringmaster and it's as near a perfect match as I could hope for....I use muffler pressure, 10/6 wood prop, 10% nitro with 20% oil and 70 foot lines.....Flawless!!!

Tnx, Mike, the "Old Harley Man" [email protected]

OS 25LA and APC 9X4 Prop

Starts + Plenty of Power = Perfect Choice!

Hi Howard,
I would go with the OS 25LA. They are currently available, inexpensive, easy starting and strong enough for a Ringmaster.
Of course, the Fox 35 is still available!
Don't try to run a 4-2 type run with the 25LA, run it in a "wet" 2 cycle and use a 9-4 or 10-4 APC prop to start with.
Bill <><

>Hi,
>So, what's the engine of choice for a Ringmaster (~42"
>span)? Here's what I'm looking for:
>- not finicky (starts reliably, runs OK)
>- strong enough to do everything - eventually
>- fairly quiet (read: muffled)
>
>I'm likely to either repair/recover a really old (1957?)
>plane or scratch build one using the old one as a pattern.
>I've plans and scratchbuilt a couple of sailplanes before,
>and the structural part doesn't seem too difficult.
>Actually, it looks different enough from what I'm used to
>that it seems like fun.
>
>I'm thinking that a strong-ish .15 or a .19 might be the
>engine of choice. OK, so there aren't a lot of .19s around.
> Maybe a Fox or OS 25?

I don't know about the Fox, never having run one. But the OS25LA will work after a fashion. Most likely it will be uncontrollably fast with any commonly-available prop.

I strongly recommend the OS15FP if you can find one. More than adequate "power", reliable as a stone, and runs on any fuel. The best-flying kit Ringmasters I have seen used the 15FP.A Veco 19 will work, but is hard to handle speedwise, and the 20FP is WAY over the top "power"wise. But you are in the right ballpark. All make for much better stunt flying than vintage 35/40's.

See many previous threads about this, and the very important control setup (the biggest key to making them fly well, even more than weight control)

In earlier times, going by sheer numbers, the Fox 35S would seem to be the choice. I used to fly mine with Fox 36X, and small shaft Johnsons.
Today I would use a plain bearing S.T 35C. Practically, today the choice would be an O.S. LA or FP 25. More power than a Fox Stunt, runs any fuel, parts are available, several ways to adjust power level if necessary.

Hey Howard,
I have a Ringmaster that I have been flying for the last 2 years and I have been using it as a test bed for several engines. The Ringmaster is one of the most versatile profiles ever built. I have seen them fly with .19s up to late model .40s. I have flown mine with an O.S. .25, 2 different Enya .35s, 2 different Mac .35s, ST G21-.35, ST C.35, 2 Fox .29s, 3 Fox .35s, Fox .36..... By changing prop dia and pitch, there was never a problem with "too much" speed. Which one was best? I like plenty of power and not to much speed, I'd have to say I think the Mac Red Head .35s with a 10-5 Top Flight prop, felt the best. Plenty of power for over the top, good speed, nice line tension. All in all very plesant.. I think you could probably put just about any good running engine in a Ringmaster and have a decent flying plane. So mount up what you like and get it in the air..

I agree that the R./OS 15 FP will work (I am flying one right now), but only if you are scratch building, and building lightly. I would not use this engine on a 50s restoration, since it likely will come out too heavy. I got my mostly scratch Ring with OS 15 FP down to 22.5 ounces, shooting for 20 ounces. This was with a stock S1-A wing (sheeted LE), contest balsa elsewhere, ultralite wheels, dyed (Rit) clear dope, light ply on the inboard doubler, and some other things. I ran the motor mounts all the way to the wing, which added wt, but drilled lightening holes in the areas you don't see. Also, I extended the doublers further aft.

Using the OS 15 FP with factory muffler on the Ring leads to a very quiet, relaxed style of flying. It is almost as if you are flying an electric model, with its absence of NVH (car talk for noise, vibration and harshness). The classic Ring. setup with a Fox Stunt 35 is like a completely different airplane, but enjoyable in its own way.

I haven't used the 20 FP yet, but the OS 25 FP provides power comparable to the Fox, with a whole lot less NVH. A lot of people use this motor on the usual suspects: Rings, Streaks, Busters, Shoestrings, Magicians, etc.

>I agree that the R./OS 15 FP will work (I am flying one
>right now), but only if you are scratch building, and
>building lightly. I would not use this engine on a 50s
>restoration, since it likely will come out too heavy. I got
>my mostly scratch Ring with OS 15 FP down to 22.5 ounces,
>shooting for 20 ounces. This was with a stock S1-A wing
>(sheeted LE), contest balsa elsewhere, ultralite wheels,
>dyed (Rit) clear dope, light ply on the inboard doubler,
>and some other things. I ran the motor mounts all the way to
>the wing, which added wt, but drilled lightening holes in
>the areas you don't see. Also, I extended the doublers
>further aft.
>

No need for extreme weight reduction with the 15FP. It's more than adequate even for a kit model. In fact, flying a kit S-1 with a 15FP and a full opaque finish (estimated weight in the 30 oz range) was so good that triggered the entire series of experiments with 20 and 25FPs.

A 20FP leads to excessively fast flights on a Ringmaster. Expect something like 3.8-3.9 second laps on 60 foot lines with the preferred 9-4 APC. It runs fine, and it doesn't seem as fast as it really is, but there's no doubt it's fast. A Veco 19 will give about 4.2 second laps in the same system, but is much less stable and far noiser with the stock Veco muffler. A 15FP with a 8.5-4.5 put you at about 4.5 seconds on 60 foot lines, and is very stable in flight.

This isn't random speculation. We did all these experiments and know how it works from multiple examples. If it doesn't work, there's something else wrong. We have not done this experiment with the 15LA, and I suspect that this engine (with it's missing boost port) will not put out like the FP.

In any case, reducing the control throw by slowing the rate is the key to good performance with any engine. It's more critical to the vintage-engine models, but if you are getting more than about 20 degrees with full hand movement you are likely to be sorry no matter which engine you use. Slow, don't "block", the controls to get just enough elevator motion to induce a stall, then back off slightly. You don't want more for "emergencies", since stalling it will create an emergency, not solve one.

LAST EDITED ON Nov-08-04 AT 03:39 AM (CDT)
 
i dont know what these guys'll tell ya ... but ... it was originally designed for a K&B 29 with a 9"6 prop ... however any 29-35(10"6 for th 35) ought be about right ... oh n be sure to put th control rod through some type of "eyelet" mounted to th fuselage about half way between th wing and th stab (so it cant bow)... itll save your airplane someday ... or ull be sayin ... but i pulled up !!! i learned to fly stunt on a ringmaster ... 53 years ago

For what its worth, I have just finished
a Ringmaster with a Fox35,test flew it
yesterday,worked well,weight 27oz ready
to fly,have made provision to mount an
OS26FS,but will need more tail weight,
the only downside.

Thanks for all the responses. Sounds like both the OS .25 and the Fox .35 would work fine. Will probably go with the quieter engine.

RE: eyelet in fuselage... Dad's Ringmaster (the restoration candidate) had what looked to be a safety pin embedded into the fuse midway between the wing TE and stab LE.

LAST EDITED ON Nov-08-04 AT 09:34 AM (CDT)
 
>Thanks for all the responses. Sounds like both the OS .25
>and the Fox .35 would work fine. Will probably go with the
>quieter engine.
>
>RE: eyelet in fuselage... Dad's Ringmaster (the restoration
>candidate) had what looked to be a safety pin embedded into
>the fuse midway between the wing TE and stab LE.

Sounds like a pushrod guide. It keeps the pushrod from bowing, and is usually needed to keep the controls tight and consistent.

The .25 sounds like the best, and will run modern fuel. Don't limit your choices to simply the OS "S" control line version. If you accept an RC version, your choices are much greater. The Thunder Tiger 25 GP, Pro, Magnum 25 or 28, GMS 25, etc., will work just as well. You can wrap a Kwik-Link around one of the tank supports and connect it to the throttle, or simply screw the idle screw in to lock it open.

All of these choices are cheaper than the OS LA, and they don't come with a plastic backplate to cause trouble in the future.

>>Thanks for all the responses. Sounds like both the OS .25
>>and the Fox .35 would work fine. Will probably go with the
>>quieter engine.
>
>The .25 sounds like the best, and will run modern fuel.
>Don't limit your choices to simply the OS "S" control line
>version. If you accept an RC version, your choices are much
>greater. The Thunder Tiger 25 GP, Pro, Magnum 25 or 28, GMS
>25, etc., will work just as well. You can wrap a Kwik-Link
>around one of the tank supports and connect it to the
>throttle, or simply screw the idle screw in to lock it open.
>
>All of these choices are cheaper than the OS LA, and they
>don't come with a plastic backplate to cause trouble in the
>future.

That is true, there are plenty of 20-32 size engines available that will fly a Ringmaster quite nicely. For an extra $15 or so there are plenty of guys who can make a venturi and supply a NVA that will be just right for whatever engine you choose, too. Good point, Tom.

Now, donning asbestos flame proof suit.........

There are a lot of guys that forget that a beginner, or retread, is just trying to get into the air, and fly! Something is needed in that case that will start and run well. Lap times, etc., are less important than getting up and getting down still in one piece. Not much is wanted in the way of trim yet, because most in this category do not know what the plane should fly like, anyway. Not a put down, just the way it is. How much more fun was it in the beginning when the thing actually FLEW?? Not cranking until your arm felt like it would fall off, etc..

Once the pattern is flown, in it's entireity, there is less of that sheer joy. Now it becomes a journey of improvement. Still a lot of fun, but in different terms.

Many, many, many more pilots would get better quicker if things are kept simple in the beginning so that flight time is maximized.

The old Michael Jordan shoes, Babe Ruth's bat, Derek Jeter's glove syndrome seems to affect very many of us.
Bill <><

>Many, many, many more pilots would get better quicker if
>things are kept simple in the beginning so that flight time
>is maximized.
>
>The old Michael Jordan shoes, Babe Ruth's bat, Derek Jeter's
>glove syndrome seems to affect very many of us.

Exactly. Just get a 15 FP if you can find one, or 25 LA (straight from Tower), get some 9-4 props at the hobby shop, slap it on, set up the controls for slow rates, and go fly it.

yep tom it was a stiffner for th control rod...probably was a saftypin ...thats what most of us used...jim

LAST EDITED ON Nov-08-04 AT 04:44 PM (CDT)
 
You've already received several good suggestions from much more experienced folks than me. That said, my best flying Ringmaster of the five I've had over the years was powered by an Enya .19 with muffler. I flew it with a TF wood 9×4 prop and flew it on .012"×55' lines. The plane's CG was just right for my flying tastes. As matter of fact, I replaced an unmuffled Fox .35 with the Enya and the balance point didn't move much, if any.

LAST EDITED ON Nov-09-04 AT 01:46 AM (CDT)
 
th ringmaster profile was meant for sport stunt...almost never used in competition except w/o out th gear for combat...lots of old fuel soaked ringmasters died that way....a real versatile airplane .... i even flew one for "C speed jr" one time and won 1st place cause there were no other entrys.... cheeeeat!!!! ...ha ha ha ha ha ha ...i have an original super ringmaster on my wall .... its pretty beat up...but i should be able to get it in shape...think ill take a before and after picture ...oh i almost forgot...add 3" to eachside of th wing so its 50" instead of 42"...it makes a world of difference in th way it flies... hmmm i may do that to that super ringmaster... maybe change it to an inverted mount....hmmmm startin to get carried away ....jim

BB: I agree that reducing control throws on the R is the way to go. I did exactly that. Combined with a Hot Rock handle, it is quite controllable. Actually, it would make a capable, one-step-up-from-an-all-wood trainer (like a Flite Streak Trainer, or an ancient Guillows or Testors). A light R with a FP 15 bounces quite nicely, butt jointed TEs notwithstanding.

My comments re the 22.5 oz of wt were based on the very positive results stemming from my own model. I will test your comments re heavier Rs next spring (20 degrees here now). But there will be some (non R) flying before the snow truly flies here. I trashed a normal (c 30 oz) R in the late Summer, so I will have to find (or kit build) another one with body mass more in line with Roseanne (well, a slimmer one).

I believe you re the R/OS 20 FP observations, certainly. But will try it on the lighter R.

By the way, tried an OS FP 15 on a Super R? Should work; I sense that the drag of this full fuse R is lower than the venerable profile standard R. I have one with a Johnson S (.33), and it is too hot, agreed.

BB: You mentioned reservations re the LA 15. Is it timed differently, or ported differently?

The only LA I have is the 46; 15 LAs don't show at the old flying field that often, even with RCers.