don't use servo reversers.

inhibit the gear channel, that will make the gear channel on your rx a slave to the elevator channel.
in sub trim menu you can trim each separate to get them close but when normally trimming like in normal flight both servos will move together even though they are in different channel. just like setting your ailerons up on different channels using the flaperon mode. You can trim separately in sub trim but when you mover your aileron trim normally both servos will change.

I agree with Stephen. A servo reverser is just one more thing to go wrong and it will not allow you to trim the elevators seperately. I use the gear channel as he recommends on all of my planes with split elevators. Between the ATV and subtrim you can dial them right in. I've had a servo reverser fail on me several years back and lost a 26% Cap 231Ex.

I've also got a 2700maH NiMH mounted about 8" behind the trailing edge of the wing to balance. I just ran a couple of plywood rails with velco on them back to one of the bulkheads. Then I put velco on the flight pack and a velcro wrap to hold everything together. The rails allow me to fine tune the balance with the flight pack and velcro rails make adjustments relatively easy accept that you have to use 12" hemostats to work on it.

I finally got everything dialed in on my ST and then pancaked it today when it failed to pull out of a flat spin. Not much damage though. The gear broke out and an SFG crushed a rib. It's decent was so slow that the impact was minimal. A couple of hours and she'll be back in the air.

One odd thing that I'm not sure how to correct is that it falls hard to the left when hovering even though it's latterally balanced. I don't think that I've ever had to work the rudder as hard on any other plane to maintain a hover/torque roll. Elevator corrections are minimal. The CG seems to be right on and she'll even tailslide 20-30 feet without correction. Maybe I'm just not used to the vertical presentation yet and not truly vertical. Any thoughts? Has anyone adjusted the side thrust?

I used a servo reverser in a 1/4 scale Extra with split elevators and had no issues, and it was the cheap one I was talking about. I no longer need them because I have a 9CAP, which has the ability to trim both with the trim switch. I don't like the idea of trimming in flight and only one elevator half moving with the trim. I've done it before, and it can be okay, but it's far from ideal. Also, when you mess with the sub-trims, you change how the servo moves throughout the range of motion, and your servos may not be well synched as a result. You don't want to change the end points in the radio if you can avoid it. If they're not moving the same distance, your linkage is not set up equally on both servos. There have been some recent articles in some of the R/C mags where they discuss the ways these features can help and hinder in different applications. For throttle, retracts, and other functions not related to control surfaces, those are great features. For control surfaces, you don't want to use them if you can avoid it.

Now, you have different points of view to look at and make your decision, Jonathan. That's what the forums are all about... =)

Crash080 - your issue sounds like a thrust alignment problem. You can try some shims under the left side of the motor mount, just very small ones, and see if that helps. Also, check to make sure that when your rudder is neutral that it is completely centered when looking at it from the rear. I've found that to be a problem in the past that can cause that issue, even when it didn't seem to affect anything else about the flying performance.

-Pat

get the plane up high and nose it down in a vertical downline, or nosedive as the kids will call it. see what way it moves, then you the same thing going upwards. then face into the wind, roll inverted, and put it in a 45 degree anglew with the nose up. see if the nose falls or the tail falls.

this will check for balance and thrust and is worth a try. i think witht he showtime it needs two washers on top left corner and 1 on bottom left. ( that is looking at it from behind the firewall not in front of it.

well i took the plane out today, but it didnt go well at all. I think it was WAY to tail heavy[&:] even at the recommended cg, i put in around 3/4 of thro, and it wouldnt take off, just before it was the end of the runway, it shot straight up into a prophang[X(] i throttle up and it had excellent verticle, but when i went back to level flight, it was so0o awkward...it went up and down for no reason. i did 2 weird circuits and decided i needed a landing immediately, i came in, and the engine cut at around 15ft. and i pankacked it, the mount holding the landing gear broke.

so0o0 was it the cg which caused it to be like that?

I've noticed that some guys have complained about tip stall with the show time and it seems to be related with the stab having some slight movement and not being as secure as it could be. The fix seems to be is to glue the stab on permanently. I have checked mine and yes there is some slight movement there. I have lots of hangar space and transportation is not a problem so it doesn't matter if the tail can be removed or not. Looking at the wing incidence I;ve also noticed that some guys have found this to be out of line to. Zeroed the firewall and found the stab and wing was +2 degrees. That didn't sit too well. checked it again with the laser incidence meter and it was +1/2 degree on all surfaces.so I think I will just leave this be. Guiess my old incidence meter is out of wack.I never did trust the old bubble style anyway. Anybody have some thoughts on this. Thanks in advance for your help. Hope to test fly it tomorrow. Just want all to be correct. My knees will be knocking anyway.

what would the plane be like if it was nose heavy?

BWD: the laser incidence meter is probably less accurate than the Robart's incidence meter, if your laser one is the Greatplanes one. I had one and it just was really really difficult to get repeatable results for me. I use a hangar 9 digital incidence meter and it works pretty well -- probably not as accurate as the robart's one, but better than the laser one. For your test flight, I would not really worry so much about the wing incidence being 1/2 degree or even 2 degrees off -- especially if all of your surfaces are off by the same amount. Measureing the incidence of the firewall is a difficult prospect compared with mearsuring your wings and stabs because you wind up with the entire weight of the bar hanging down from the engine. Also, measuring the incidence of the showtime with the ailerons and elevators hinged and installed is extremely difficult. Just a tiny hair off and it shows up as +/- 1-2 degrees.

The plane tends to jump off the ground after a long take off roll because the stabs are in direct line with the wings. Other planes that have this arrangement suffer from this as well. The fix is taller main gear, or bending your tail gear down so as to make a positive angle of attack when sitting on the ground.

The showtime flies pretty well when nose heavy and pretty well when tail heavy. When nose heavy (recommended cg point) it does fine with most maneuvers and lands a little easier. When tail heavy, it still does maneuvers fine and does really well with 3d stuff, but landing (for me anyway) is much trickier as when the plane slows down, the tail starts to drop and it will sort of go into a harrier. Just work at keeping the nose pointed down until the flare for the landing to fix this.

The only other thing really to do with this airplane is to spend a lot of time making sure your elevators are PERFECTLY matched. Make sure they not only go up and down the exact same distance, but also at the exact same speed. If using Hitec digitals, you should borrow a programmer as they come with different settings on endpoints and speed values from the factory -- I found this out after installing new hs5645's and not being able to match them even with a matchbox until I programmed them.

you have to hold trottle untill the tail wheel lifts from the ground....no up elevator untill then....then onece that happens ease back on elevator....this is how all theese planes are meant to be taken off....if you hold to much elevator the plane will wait untill it has enough ground speed then shoot up.

use an ele/flap mix on the raido an it will take off fine
just remember to turn it of in flight

Just got done working my way through this thread (over the course of a few days!!) and there's a ton of info here!! I'm just getting ready to build my Showtime and wanted to run my setup past you all to make sure I haven't overlooked anything.

I'm using the Saito 125 on a Hyde mount. Hitec 5625s and a 5645 in the rudder set up for pull-pull.

I'm planning on using Robart hinges so as to avoid the CA failure issue, but I'm not 100% sure which size to use. I'm thinking 1/8" but do any of you have any other suggestions?? Also, do I need to run some sort of fuel pump or tank pressurization device with this motor if I set the tank back to center of CG?? I've seen and heard mention of the Cline and Perry parts, but I'm not real sure what they do or how they do it.

If there's anything else I've overlooked, please let me know and THANKS!!!!

ILVSMOG,

1/8" hingpoints should be sufficient for the ST as long as you use enough of them.

As for the pump issues either of the two methods will work and yes, you should run one any time the tank is mounted at or near the CG. I've found this to be especially critical on 3D aircraft that you intent to hover. Without a pump the engine will sag and/or simply run out of fuel as the pressure created by the muffler tap simply cannot create the pressure differential needed to ensure positive flow. As far as the Perry or Cline Regulator goes it's a bit of a toss up as they both have their strangths and weaknesses. I am running the Perry in my ST with a Saito 1.50 and it works great but it took a bit to get the flow to the engine dialed in correctly. Once set however, I haven't had to touch it. I've used a Cline regulator to solve a fuel flow problem in my GP Super Stearman with a Saito 1.80 where I was having both draw and siphoning issues (siphoning on the ground and then leaning out at the top end resulting in loss of rpm). The Cline is very simple to set up, solved both problems, actually provides a more consitent flow regardless of engine speed and there are no settings to mess with. Essentially it converts the entire system to a pressurized system by placing a check valve in the exhaust pressure line to build pressure in the tank. There are no settings to mess with and they even recommned that you just leave it hanging in the fuel line so there really are no mountng isses to speak of. The only issue that I have run into (and they mention it in the directions) is that you will have to choke the engine until sufficient pressure builds in the tank. This is an issue on Saitos as they no longer provide chokes. I fabricated one from a 4-40 rod, a rubber stopper and a spring so that I just push a ball driver through a hole in the cowl and stopper seats in the "velocity" stack. When I release it pulls up out of the way. Sealing the exhaust and turning the engine over does not work.

So it's up to you either will work. I think the Perry is about $40 while the Cline is $60.

I would also recommend, as mentioned in the thread, epoxying the elevator halves together. Even if they are solid on day one they get pretty loose over time to the point that they begin to affect flight behavior.

Thanks for the info. Since I'm planning to use this plane to develop my 3D skills (including hovering) then it sounds like I should go with the Perry pump. Any mounting or setup suggestions for the Perry on this plane with the Saito?? Since the Perry uses vibration and motion to operate, will my soft-mount give it trouble?

Thanks!!

The oscillating pump, which is the recommended one to use with 4-cycles, needs to be mounted to the engine perpendicular to the crankshaft. Since you should be mounting it to the engine the soft mount will not affect performance. With a little modification I was able to use the mounting plate that is included with the pump. Basically I drilled two new holes in it so that the pump cleared the cowl and mounted it off the bottom two screws of the rear crankcase cover. With the engine mounted inverted the pump is above the rails of the mount ,close to the inside of the top of the cowl. (Hopefully that makes sense. I'd send pictures but I'm traveling). It doesn't quite meet the the 1.5" from the crank centerline that Perry recommends but it's close enough that I have not noticed any performance issues. The pump will not work if mounted to the firewall when using a softmount.

Ok, thanks. That actually helps a lot. It looks like space is going to be tight in that cowl, so that should get me going in the right direction!

Well gang, I chickened out on the Saito/Perry setup and just bought a new YS FZ110-S. Seemed to be the more performance-oriented and simpler package. Both good things for what I want to do with this plane.

Can anyone reccomend a good aluminum spinner that fits the YS motors and a 16" prop??

by a higley safety spinner. just threads on....thread is 8mm.

Hi Fellows,
Before I read through the entire forum to find it again can someone tell me if the 7 7/16" back from leading edge next to the fuse. for CG is correct? That's what's stated in the manual, but I'm still having some Balance issues.

Hi everybody.

I was a Showtime owner and this was my best plane of my life!! Nothing can fly like this thing. Its fast and slow when you need. Stable and very very 3D capable.

But my Showtime is too old now and I decide to retire it. I was flying it with an OS 160 FX. It's an amazing combo, but this engine have a lot of vibration for this plane, what can damage it with time...

So now I decide do order another Showtime and I want to use a 4 stroke now. Can somebody tell me with engine I need to choice??

Here in Brazil, my best choice is a Saito and I was thinking about the 150 one.

Can somebody tell me what this engine can do in a Showtime?

It will do anything you want

I went with a Futaba MAS-10 Servo synchronizer with my 7Cap radio. You can trim the elevators individually and using the radio's trim tabs for in-flight up/down trim. I wasnt ready to buy another radio.

HoverLow,

The Saito 1.50 is a little on the large and heavy side of the spectrum for this .90 size plane, but people have used it and it has proven to be a VERY powerful combo.

Hi. Thank you, guys, for the fast aswers.

Hey, P-Diddy, in your signature says you do have a Showtime powered by BCMA 26cc.

Is this a gas engine? If yes, this engine must have the sames power and weight of the 160FX, haven't it??

If yes again, how your engine flys the Showtime?

Mine, with 160, was really awsome!!!!!!

But I noticed some problems that I think is about the weigth:

- Was very hard to make inverted harries, becasue the plane started a inverted flat spin;
- A HUGE snap tendence (http://www.youtube.com/watch?v=us35LQWSK9w);
- A good amout of dead weight on tail to bring back the CG (210g);

The inverted harries was my big problem, becaues I couldn't t pratice this maneuver on my Showtime.

Of this things, my Showtime was perfect. So, did you notice some things like thoses?
Maybe, have I a CG problem never solved??

Hi,

I spent the last week reading this thread. 106 pages takes a while to read and now that I'm done all I have to do is decide which engine I want to install. I have an Evo .26 gasser that I can use. Also, I have a new Saito 125 in a box or my trusty YS 110. I'll have to think about this for a while be for I begin to assemble the aircraft.

I'm going to use Robart hinges and do away with the CA hinges. Re-enforce the landing gear block, check the incidence on the model and use a smaller tail wheel.

Thanks to all who commented on this model, it will save me a lot of time during the assmebly process.

Regards,
Chuck

Yes, the BCMA 26cc is a gas engine, and although it isn't as powerful as the O.S. 1.60 glow engine, (gas engines of the same displacement will always be less powerful) it still pulls the Showtime around with authority. The BCMA engines are very lightweight for gas engines, and I did not have to add any extra weight. I just moved the Rx battery pack toward the tail until it balanced. Then I built in a ply holding plate for it.

The snap tendency is present in many planes that have 3D throws and performance, and the ST is no exception. I was always ready with the aileron when pulling hard on the elevator. If I pulled full up, it didn't snap at all, just entered a wall and I hovered from there. The BCMA 26 has plenty of power to pull out of a hover.

Harriers, whether upright or inverted, can be pretty challenging with this plane. I found that pulsing the power helped to keep it from wing-rocking too much.

I have only ever flown one plane that didn't have ANY snapping tendencies or rolling-out tendencies during hard elevator maneuvers, and that is my Aviation Models 33% Yak 54, (a.k.a. SD Models and TOC). I have flown many other 3D capable aircraft and have found that they all do this to some extent, with only that one exception. For me, it is not a deal-breaker. I do what I can to minimize the rolling-out by putting a small amount of negative incidence in the wings, laterally balancing the plane, and ensuring that both elevators move evenly. Then, I just plan ahead for when the plane wants to roll or snap.

The ST is plenty capable of 3D and pattern, (I won 1st place in a small Sportsman pattern competition using my ST with the BCMA 26 in the nose).

Unfortunately, I recently traded mine with that engine for a helicopter set-up, but the new owner of the ST really likes it a lot.

-Pat