OS la15 in a ringmaster?

[GonzoBonzo]

Has anyone tried an OS 15 on a Ringmaster?  I'm building one now, and thinking a 15 would pull it in a RC type run.  Also thinking about using Spectra lines.  Thoughts???

TIA

[Brett Buck]

Has anyone tried an OS 15 on a Ringmaster?  I'm building one now, and thinking a 15 would pull it in a RC type run.  Also thinking about using Spectra lines.  Thoughts???

TIA

  A 15FP is ideal. David and flying someone's 15FP Ringmaster (kit, complete will full opaque finish) is what kicked off the "small engine" experiments I did. FAR better than any of the 35-sized airplanes. 15LA, I don't know. It's not  as strong as the 15FP.

   A 20FP is too much - 3.8 second laps with an APC 9-4. If you are willing to spring for a carbon prop, you can depitch it to 3.5 and have a chance.

     I know nearly nothing about Spectra or other synthetic lines, but don't assume that because it's a 15, it won't pull very hard. We generally use .015x60-62' stranded on these type airplanes - .015 because it pulls pretty hard at 80 mph, and 62 because it goes 80 mph.

  BTW, running in a constant medium 2-stroke isn't an "RC run" - it's a CL stunt run, since about 1988. That's how a 40VF runs, and every time Paul Walker showed up at a NATs with a 40VF, he won.

   Brett

[Motorman]

Do you plan on doing stunts or flying in the wind?


MM

[Dane Martin]

Like Brett said, the fp is more powerful. But from my own experience the 15la does fly a light ringmaster (well built i should say).
 I believe i flew it on 56 or 58' lines though. Like Brett said, the 15fp pulls better than the 15la

[Randy Cuberly]

I had, and flew in Old Time competition for several years, a very light Ringmaster (19 oz) with an LA25 using a 10-3 APC prop.  The airplane was the perfect tool for that event.  It flew on 62 Ft lines and would fly the OT pattern or the modern pattern easily.  I did OK in competition with it but never learned to conquer the Ringmaster major fault which is landing one of the things without bouncing...Points you can't afford to give up at the top levels of competition.  The airplane was a ball to fly.  I actually taught several people to fly with it and in the end gave it to a beginning flier who used it to go into Intermediate class in PAMPA.

I believe the LA25 to be the perfect engine for a Ringmaster....15?  I've flown a couple with 15's and found them more tedious to fly and required shorter lines!  Of course I do most of my flying in Tucson at higher altitude and HEAT!  That does make a difference.

Randy Cuberly

[Steve Helmick]

Emil Kovac (from Issaquah, WA) built a lot of very light Ringmasters, down to 16 oz with a .15FP, and about 20 oz with a .25FP (this was prior to the LA's). The .15 on 16 oz was said to be excellent in perfect conditions, but with a bit of breeze, it sucked. The .25FP was more practical for typical contest weather, and probably a lot better for fun flying. I'm thinking that Emil didn't use the dreaded .21FP, because he was flying .40 or .46 powered sub-40 oz  Humongeese when the .21FP was all the rage. Anyway, I'd either use a .25LA or a Magnum XL .25, because I have some.  Steve

[Brett Buck]

Emil Kovac (from Issaquah, WA) built a lot of very light Ringmasters, down to 16 oz with a .15FP, and about 20 oz with a .25FP (this was prior to the LA's). The .15 on 16 oz was said to be excellent in perfect conditions, but with a bit of breeze, it sucked.

  Probably too light. The one Dave and I flew was in the upper 20's at least, and more likely low 30s. It had no real problems with reasonable amounts of wind (5-10).  No weight = no line tension.

   Note this was all with a 15FP, not LA.

     Brett

[Mike Griffin]

I am with RANDY on this one.  I have built and flown many Ringmasters(read between the lines) and I have found the LA25 to be a great engine for the model.  The 15 may be good also but I gave never tried one.

Mike

[Larry Fernandez]

I built a Ringmaster a few years back and powered it with an FP .15
A couple of flyers in Alameda argued that the Ringmaster was designed for a Fox or McCoy .35 and there was no way it would fly with a .15

Well mine flew just fine thank you.

Well enough for Uncle Jimby to win Old Time Stunt at the Golden State Stunt Championships with it. Twice

It weighed 19.5 ounces flew with an APC 8x4 prop on .012 lines about 58 foot long.

I have to admit that it wasn't that much fun to fly when the wind came up.

Larry, Buttafucco Stunt Team

 

[GonzoBonzo]

Thanks for all the replies.  I checked the OS site for specs.  The FP was listed at .41 hp, and the LA at .40.  Doesn't seem like much difference.  The FP was ABC, and the LA is ABN, maybe the FP had different porting.  The LA is still available, so I think I will try it.  The all up weight is a little over 6 ounces, about the same as a Fox.  I do remember long ago a buddy of mine stuck his Fox .15 (looked like a miniature combat special), on my kit built Flite Streak and it flew it just as well as my Fox.  I was blown away.   

[Brett Buck]

It weighed 19.5 ounces flew with an APC 8x4 prop on .012 lines about 58 foot long.

I have to admit that it wasn't that much fun to fly when the wind came up.

  Probably too light, but try something like an 8.5-5. As I recall, the one we flew used a Master Airscrew 9-5 cut down to 8.5.

     Brett

[bob jablonski]

With a .15 I would lean to a Ringmaster Jr kit
Mr. Bob
Countyline Hobbies
Grovertown, IN.
574-540-1123
countylinehobbies@yahoo.com
www.countylinehobbies.com

[GonzoBonzo]

Well I found maybe the ultimate engine.  I was looking at engines last night on ebay.  Shtterman is selling a new Enya 15.  It's a CX model like the bigger motors they produce.  I messaged him for the specs, and he said the CL version is 4.8 ounces, and puts out .51 hp.  It's a ball bearing engine with boost port.  Must have a light case.

http://www.ebay.com/itm/291659186042?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

[Brett Buck]

With a .15 I would lean to a Ringmaster Jr kit

  Maybe for an extremely weak 15, like a Fox, Max II/III, but no way with something like an FP. The Jr. is smaller than a lot of 1/2A stunt planes. That's the problem with defining the engine by size - a .15 could be anything from a Fox slantplug, which barely runs, to a Zalp 2.5 that puts out around 3 hp.

     Brett

[Fredvon4]

Bret brought a funny memory to me as I had a hand me down flight streak and no  READY TO USE .35 motor. A friend convinced me the FORA .15 I had a spare of would fly it


Yes it will...at near 105 MPH !

[wwwarbird]

 A 15FP is ideal. David and flying someone's 15FP Ringmaster (kit, complete will full opaque finish) is what kicked off the "small engine" experiments I did. FAR better than any of the 35-sized airplanes. 15LA, I don't know. It's not  as strong as the 15FP.

     I know nearly nothing about Spectra or other synthetic lines, but don't assume that because it's a 15, it won't pull very hard. We generally use .015x60-62' stranded on these type airplanes - .015 because it pulls pretty hard at 80 mph, and 62 because it goes 80 mph.


   Brett

 Brett,

 Am I reading this right? You're saying that your FP.15 powered Ringmaster flew at 80mph on .015x62' lines? Even at 60' that sounds really fast for that combo...

[Brett Buck]

Brett,

 Am I reading this right? You're saying that your FP.15 powered Ringmaster flew at 80mph on .015x62' lines? Even at 60' that sounds really fast for that combo...

   The 20FP ringmaster flew that fast, and I would expect the 15FP version to be in that ballpark, when set up correctly. 3.8 seconds on a 65' radius  (62' lines, the length of the inboard wing, and the rotation of Uncle Jimby's arm) is 76 mph. BOX-STOCK 20FP, stock APC 9-4, Ringmaster you can see on the box-top art for the RSM Ringmaster kit (the 20-pointer), in the 25-28 ounce range.

     As noted, I would start with something like a 9-5 on the 15FP and then trim it as necessary to get the speed VS setting correct. The airplane I was referring to was around 28-30 ounces with a BOX-STOCK 15FP, and used ~.015x60.

   These engines are very powerful compared to ancient slag motors like the Fox 15 - unless someone decides to "improve" them. Paul test-flew his 15FPs in his Mike Dietrich "Cobra". I flew the Skyray 25 with the 15FP, and it was still better than it was with a Fox 35 and could easily fly full patterns in 10-15 mph wind.

     I am less convinced on the 15LA but I haven't ever run the one I have. I think most of the other issues above indicate that the airplane was too light for good performance in the wind. You *are* counting on carrying some momentum to a much larger degree than you do on a modern stunt plane. It's counting on it much less than a pre-80's 4-2 break engine.-powered-airplane.

     Brett

[wwwarbird]

 Hmm, interesting. The FP.15's are great little engines but I've never felt that they had that kind of power, at least in my experience. I've always ran them box stock with 8x4 or 8x5 props, never even considered running a 9 inch on one.

 I think I've got like six NIB FP.15's on the shelf, maybe I need to draw up an 80mph B-36 stunter...

[Randy Cuberly]

Hmm, interesting. The FP.15's are great little engines but I've never felt that they had that kind of power, at least in my experience. I've always ran them box stock with 8x4 or 8x5 props, never even considered running a 9 inch on one.

 I think I've got like six NIB FP.15's on the shelf, maybe I need to draw up an 80mph B-36 stunter...

And get two healthy guys to hold on to your belt when you fly it!!! 

Randy Cuberly

[bob jablonski]

Is this engine that hot? I have one on my Acromaster and it isn't a rocket (for my ability or lack of )
Mr. Bob
Countyline Hobbies
Grovertown, IN.
574-540-1123
countylinehobbies@yahoo.com
www.countylinehobbies.com

[GonzoBonzo]

  Hey Bob,

  I think if you run the engine the way it was made to run, you WOULD have a rocket on your hands.  8-4 prop, cool power fuel, 52 ft lines, and the engine set just rich of peak so you get a distinct RPM increase when you point the nose up.  I think the Acromaster is a bit larger than a Ringmaster Jr too.  I'm just trying to avoid hanging a 8.5 ounce engine on a plane that was designed for a 4.5 to 6.5 oz. engine.  

[Brett Buck]

 Hey Bob,

  I think if you run the engine the way it was made to run, you WOULD have a rocket on your hands.  8-4 prop, cool power fuel, 52 ft lines, and the engine set just rich of peak so you get a distinct RPM increase when you point the nose up.  I think the Acromaster is a bit larger than a Ringmaster Jr too.  I'm just trying to avoid hanging a 8.5 ounce engine on a plane that was designed for a 4.5 to 6.5 oz. engine.  

  Any of these engines are *much* more powerful that what they meant by "for engine sizes .09-.19" in 1950. That's sort of a fundamental problem with trying to specify the airplane by engine size. A 15 could mean anything from a Fox 15 (weak) to a Fora 2.5 FAI combat engine. Put a 8-4 fiberglass on the Fox and you might get 12000 RPM out of it for a while. The Fora, maybe 30,000 - more than 6x the power.

  It's more or less true up and down the board. Look at the attempts to revive B Team Race. Many people used well-respected vintage engines like the Dooling or (Duromatic) McCoy red-head 29. Bob Hazle used a slighly modified 25FP and went *20 mph faster*.

   I don't know about the 15LA specifically, most of what I was saying above was comparing various FPs that we had actually experimented with locally during the "small engine experiments" in the early-mid 90's. Next time I go out, I can plunk a 15LA and FP on my Skyray 35 test goat and see what happens. It's larger and draggier than a Ringmaster, and I have flown full patterns in ~15 mph winds with 15FP with no issues. I know for certain that a 15FP on a "35-sized" Ringmaster is a good combination if you get everything else right, far better than any of them with a Fox 35, even with kit parts.

   Brett