S1 Ringmaster

Model looks Good onelife , I like the color scheme you have went with !

Thank you

I flew it today using a stooge a little rough on the take off I didn’t have much control at first out of the gate but then it straightened up lol. Flew ok the wheel feel off so it had a rough landing and broke the prop but I can live with that.
The only thing in both my shoestring and now this Ringmaster I always have to fight it it seems to keep wanting to climb on me. Any one have the reason behind this and a cure for it I would appreciate it thanks for all the help.

Good for you. Flying it.

Tail heavy, check the balance.

Lines out of adjustment. Clamp the elevator to the horizontal stab and adjust your lines so the handle is vertical.

I will check the lines but on the sterling kit for the S1 it doesn’t give a dimension for CG not that I seen any one have a dimension?

It came out a total of 33 oz with fox 35 on it

Roll pin/spring dowel, good idea....

Coxfledgling wrote:Roll pin/spring dowel, good idea....

??

Top post, line 14, hardened roll pin....I know them as a spring dowel. They are made from spring steel and have a lengthwise split. They are used in all sorts of machines to retain and peg stuff in position, usually on a shaft.

I imagine these are fitted into the undercarriage placement holes in the fuz and the undercarriage wire end fits into the pins hole.

They are a little heavy ( and I don't have any ) so I would probably use suitable metal/brass/alloy tube, which I do have.

Most under arts for cl models I have are "sown" and epoxied to a ply fire wall or bulkhead, but other methods are employed like using the engine mounts.....

Yea I’m not sure we’re the CG should be

I seriously doubt your plane is tail heavy. Not impossible but not likely as almost every Sterling kit builds on the nose heavy side. If this is something your pretty certain of, put a APC 10x5 on the nose . I never use 10" props on a Ringmaster but the APC 10x5 can be very helpful to not only providing good thrust but it tends to calm any resonating of the engine. It also is probably one of the heaviest props available today in that size.   I've really poured the lead into the rear of the Ring and it makes little difference. I would insure that the controls aren't sticking in any way. Insure your handle is set neutral. If you pick the plane up with your finger tip at the  exit point of the first leadout, the plane should automatically nose down. I prefer my balance point on the Ring to be the halfway point between the first leadout and the front of the leading edge. Check to insure your engine is also square to the fuse and not pointed up with any incidence. For this very reason I insure I have a register down the fuse to insure everything is parallel to the thrust line. So before any step, I square the engine mount area, wing chord and stab line.

            I would also check the control horn and insure that where the pushrod is connected it's totally free. Even a sloppy hole where the wire is wiggling isn't a bad thing as it can assist in calming any hunting up and down. This may only require opening it up slightly.

Ken Cook wrote:I seriously doubt your plane is tail heavy. Not impossible but not likely as almost every Sterling kit builds on the nose heavy side. If this is something your pretty certain of, put a APC 10x5 on the nose . I never use 10" props on a Ringmaster but the APC 10x5 can be very helpful to not only providing good thrust but it tends to calm any resonating of the engine.   I've really poured the lead into the rear of the Ring and it makes little difference. I would insure that the controls aren't sticking in any way. Insure your handle is set neutral. If you pick the plane up with your finger tip at the  exit point of the first leadout, the plane should automatically nose down. I prefer my balance point on the Ring to be the halfway point between the first leadout and the front of the leading edge. Check to insure your engine is also square to the fuse and not pointed up with any incidence. For this very reason I insure I have a register down the fuse to insure everything is parallel to the thrust line. So before any step, I square the engine mount area, wing chord and stab line.

            I would also check the control horn and insure that where the pushrod is connected it's totally free. Even a sloppy hole where the wire is wiggling isn't a bad thing as it can assist in calming any hunting up and down. This may only require opening it up slightly.

Agreed Ken, there should be a question mark after my "tail heavy" remark above.

Bob

Bob, everyone is different. What is nose heavy to me or you is not necessarily the same for the other pilot. I know my son for example flies with planes so tail heavy I can hardly fly them. But from a engineered standpoint, I feel that most of the profiles Sterling offered were designed to be nose heavy. This isn't always a bad thing as under power the plane will seemingly fly fine. it might turn like it needs some power steering, but it will still maneuver fairly. When things get on the tail heavy side, coming out of a loop and one finds it difficult to recover level is another story. A sure sign of tail heaviness is the inability to control the plane in a level flying manner. The plane is going to want to hunt up and down because the pilot is offering inputs to maintain level flight. Unfortunately, this telegraphs out to the plane which is now hunting up and down wildly.

It’s all good info thanks everyone, I’m leaning towards the thrust line myself how do I run a cord line now with the wing in the plane ?
Or do I just In large the holes and move the engine a tad ?

Can you visibly see that the engine has positive incidence upwards? Many times I reconfigure the engine mount to the centerline of the wing. Obviously a moot point here. Reason being is that I can triangulate the measurement from prop tip to trailing edge. The next question is, how do you retain the engine on the plane. I wouldn't hesitate to open the holes with number drills. While I'm not a fan of enlarging the mount holes in the engine, done properly with the correct size drills, you hardly even notice. It may only be even one or two bolts preventing the engine to tweak. Have you loosened the engine and tried to tweak it? At this stage, it's easier to give it the ole it looks about right and go try again. Other factors can also be at play here such as stab incidence as well. It's always good to have modeling clay when you go flying. If you feel that the model is tail heavy. Squeeze out some clay and place it on the underside of the nose and try it. It's a quick remedy and when done you can weigh it and glue some lead in later.

I just found this post from Dennis Toth on Stunt Hangar. I have to agree with this statement. Just for the record, I'm not the same Ken in this post.

CG for S1 Ringmaster is 1 1/2" behind the leading edge as a starting point, closer to the leading edge is better then rearward. Like Ken said if it floats up when the engine quits it is tail heavy, (this is not normally the case as they tend to be nose heavy with most engine/mufflers), remove tail weight (if you have it) or add a heavier muffler, prop or spinner).

Thanks everyone I have to find a spinner that fits a Fox 35 dubros spinner there isn’t enough room to tighten prop nut

Seeing that your using a wooden prop, this can be problematic when the prop requires tightening which should be checked regularly.
It will come loose due to contraction and backfires resulting in you to remove everything to tighten it. Generally, this is very audible with the Fox .35. The drive washer is a very crude fit onto the shaft cogs. When the prop comes loose, the engine sounds like something broke inside as it clicks very loudly when flipped over.  Not only does a spinner  add further nose weight and vibration, it becomes difficult to clock the prop.

       If your heart is set on using a spinner then you need to go this route. When you run into issues like this with a short shaft the solution is to get a spinner nut which recesses back into the spinner backplate. Dave Brown makes various lengths to accommodate this problem.

Is adding a weighted spinner or nose weight to a Fox 35 hard on the engine? Should I add weight elsewhere? And what is the shaft on a fox 35 is it 1/4 x28 ?

Ken Cook wrote:Seeing that your using a wooden prop, this can be problematic when the prop requires tightening which should be checked regularly.
It will come loose due to contraction and backfires resulting in you to remove everything to tighten it. Generally, this is very audible with the Fox .35. The drive washer is a very crude fit onto the shaft cogs. When the prop comes loose, the engine sounds like something broke inside as it clicks very loudly when flipped over.  Not only does a spinner  add further nose weight and vibration, it becomes difficult to clock the prop.

       If your heart is set on using a spinner then you need to go this route. When you run into issues like this with a short shaft the solution is to get a spinner nut which recesses back into the spinner backplate. Dave Brown makes various lengths to accommodate this problem.

Yes the wooden prop came lose a few times and yea it sounds like something cracks when it does. Since then I put a plastic prop on. Bob brooks sells those prop nuts that recesses back into the prop washer I think that’s what your saying. Actually the one on the RM is one of his
I will just add a oz under engine in that cut out for motor mounts ??

I personally don't like adding weight to the shaft on any engine. That's me though. I wouldn't want to run a marathon with 10 lb sneekers on. I've run spinners on the Fox only to experience issues using the old snap on style Dubro spinners. These might have been the Goldberg spinners. They tend to be really out of balance and can cause vibration issues resulting in the spinner coming off. I really don't like using is heavy hubs on a Fox .35. I've seen many use them but I find it concerning especially in a backfire. The valve cutout in the shaft has little to no radius and the shaft breaks or cracks out of one of the corners.

Thanks Ken. Speaking of vibration I’m getting a Tremendous amount of vibration I extended the motor mounts back to the wings and I added 1/8 inch Aluminum mounting brackets because the fox bottomed out on the inboard doubler.

Using washers under your engine lug is a very bad idea. It doesn't allow the engine to be properly tightened and it will unloosen making black oil everywhere. Use the proper thrust wedges or don't use them at all. I vote for not at all because it does little to nothing. Make certain that no part of the engine is touching the fuse other than the bolts passing through. I use Master Airscrew props all the time and rarely are they balanced. Sometimes you might have to run a different prop such as a 9x6 or 9x7 to get the rpm's up to get it out of that resonance.

Yes I have a very bad vibration I been try to figure it out.
If I remove those brackets I have under engine the Fox bottoms out and will not seat properly. In order to have it seat properly I have to cut a hole with a hole saw on the inside doubler. Is that what you recommend?  And would you use that 9-6 prop on the 35?
And where is the black oil coming from ? I get that on the shoestring also but that one doesn’t vibrate as much. How do you not have the engtouch the fuse at all. It has to sit on the mounting bracket on the engine?