Showtime 4d snap and other problems
 

(because the other thread is long and quite difficult to follow, a new one)

I've did already 15 flights with my showtime 4d. I'm not very happy with it. It's equiped with a saito 120S.
When I pull up quite roughly in flight on half throttle the showtime snaps out.
I've moved the CG to the back. It snapped less (I think). I don't know if I can put the CG more to the back because last time during the landing the showtime felt backwards which resulted that my tailwheel touched the ground first and the plane felt hard to the ground and my mainwheel carbon broke and smashed in one main wing.
My Showtime is underpowered. I can hover it on full throttle with a 16x4W prop (not for long). Maybe the underpowering could be the reason why it snaps so easily...

Does anyone have a showtime with the same engine as me, but who can hover properly (not on full throttle). If so which fuelmix and prop are you using?

Some thoughts I had: - Maybe the Showtime isn't made for (extreme) 3D flying.
- Because it's underpowered, you always have to maintain speed??

Does anyone had the same 'snapping-problem'. How did you solve it?? How is your CG?

Thanks!!

RE: Showtime 4d snap and other problems
 

Sounds to me like you have to much throw in the elevator, that will make an airplane snap when applied abruptly and full throw.
Thats my theory, if you don't like it I have others:D

I am watching you
Larry S

RE: Showtime 4d snap and other problems
 

It snaps already when I give 50% elevator, when it is in the High rates. I've been thinking that maybe my airspeed is already to low when I go into a hover and the low airspeed is the reason of the snapping...

What is you other theory then?:D:D

RE: Showtime 4d snap and other problems
 

:)The Showtimes snap out a sudden elevator movement. I could never get it solved on mine. I loved the plane in many ways but could never get fully comfortable with it. Especially while doing 3d. Always made me nervous.

I think it's the plane and you can try anything you want but it won't solve it. I think the wings shield the elevators somehow at certain angles and that's what causes the problems.

Thanks
Barry

RE: Showtime 4d snap and other problems
 

I have just the same feeling;) I'm more nervous while flying the showtime then I am while I fly a jet [8D]

RE: Showtime 4d snap and other problems
 

you can give full elevator if you do it at the right time. if you are attempting the tightest loop ever, maybe it will snap, but for anything within the realm of imac or 3d, you should not have problems with this model. i don't know why you would want to do a 10 foot loop anyway. caps and giles have this reputation and it is unfounded. these are aerobatic planes, designed to perform beautiful snap rolls and spin entries. if you want a floater, go profile, they have more wing area and less weight. but they do not do awesome snap rolls do they? the showtime is a mix. a mix of pattern and 3d. that is why it rocks.

here is my video with the showtime, http://www.hiddenhangarrc.com/video/ click on "vinnyshowtime"

RE: Showtime 4d snap and other problems
 

I agree. I have a "timeshare" Showtime in California that I haven't flown yet, but my buddy says it is absolutely awesome! I watched another friend fly his and he was doing all the slow-type 3D stuff with no problem, low enough to touch the rudder, and that was on the same day as the maiden. I can tell by the design that "pop-up" style hover entries will be difficult to do without it snapping out - just don't do it and you'll be fine.

RE: Showtime 4d snap and other problems
 

Sounds to me like you don't have the airplane set up well, and you're expecting it to fly like it won't. Here's the general rules for 3d type airplanes, build it light, and fly it right. If you are at high speeds, do not pull huge amounts of elevator at high rates. Half throw at half throttle should make the plane snap, if it didn't something would break, as you are imparting too high of G-loading for the airframe. If you are flying around at higher speeds, it needs to be at low rates, or with high expos on high rates. Don't use the large throws except when flying slow 3d/high alpha type maneuvers.

Things to look for on this plane to cure snapping problems, wingrock in high alpha, weird rolling tendencies etc are CG (front and back, and side to side), even control throws on each half of the elevator, and having the elevator halves matched as far as speed. If those halves have any difference, it'll roll with elevator input, which combined with a high speed stall (like what you are getting into) will make it snap.

As far as your power problem, I ran the same plane with the same engine with an APC 17x4W prop, and it flew beautifully. I kept it light with a small 4 cell pack, and mini servo on throttle, and it hovered at about half stick, with plenty of pull out. Incredible flying plane all around, did the nicest high alpha knife edge you've ever seen, and was very stable in the hover and torque roll.

RE: Showtime 4d snap and other problems
 

to pop it up, you have to use a spoileron mix. just hold full elevator and spoileron and add a little power, pops up real nice. otherwise, it will mush and climb begore stopping, and that is not acceptable, is it?

RE: Showtime 4d snap and other problems
 

ive got a fs 120 os on mine and it flies really nice powers through anything boar a hole in the sky hovers 1/2 throttle full throttle go unlimited i normally fly 60cc gassers and this plane and engine combo works well together i had a evolution 100 on it and it sucked, i took this fs 120 i had off of my cap 232 and put it on here and with a apc 15x6 and 15 % nitro 4 stroke cool power fuel its great a little nose heavy still working on that when i have time, can pull full up and wont snap, great harrier plane. make sure your plane is balanced not just cg but ballanced as seeing which wingtip is heaver bc with the 120 on it if its mounted horizontally your right side from behind the model will be heaviest so you will add weight to the opposite wing to correct this. its better to correct it on the ground than to trim it out in the air. let me know how it goes.
Chris

RE: Showtime 4d snap and other problems
 

My showtime will do a wall beautifully. I run a Saito 150 on it. I have about 50 degrees on my elevators, you just have to make sure they are equal.

RE: Showtime 4d snap and other problems
 

Thank you guys for your replies. I will rebalance the plane (back-front and left-right).
I'll try a 17x4W prop and let you know how it goes.

Thanks again!!

RE: Showtime 4d snap and other problems
 

It's your setup and/or you. About the only way I could get mine to inadvertently snap was with too much rudder. the Showtime is an awesome 3D plane that will do incredible walls and parachutes, etc.. with absolutely no snapping tendencies IF you have it setup correctly.

RE: Showtime 4d snap and other problems
 

@ncrego
Now I have ZERO pullout (with the 16x4W). Will the 17x4W make that huge difference?? I use tornado fuel with 10% nitro.
Somewhere I've read that a saito engine needs a long break-in period. Is this true?? In this case I need a little more patience...

My showtime is a little heavier than yours. I've used a NiMH battery (5 cells) and a standard servo on the throttle.

RE: Showtime 4d snap and other problems
 

All I can tell you is that mine had plenty of power, with good pull out from a hover, not a rocket, but it had plenty of authority, and was easy to get out of trouble. I ran my Saito with 15% or 30% (depending on if I was flying my heli that day, I just ran it on my heli fuel rather than bring 2 jugs out), and it worked great. My Saito had around 5 gallons or so through it when it went in the Showtime, and I probably put another 2 gallons on it in there before I got rid of the whole lot and moved up to a DA-50 in a Yak, and it always ran well and had plenty of power with that config.

RE: Showtime 4d snap and other problems
 

My Saito 125 in the Showtime did not start to make good power until about 3 gallons. By 5 gallons it was a beast. I run a 16x6 APC on 30% (I'm at 2,500ft altitiude.)

I have incidence issues with my Showtime and it needed a lot of left aileron trim to fly level. I never could find the reason for that even after fixing the incidence and checking lateral balance it still rolled right. But, with the SFG's on it flys amazing - even with the trim issues - precise like a pattern plane but also it will do any 3D manuver you can fly. Until I fixed the stab incidence it would snap out even on low rates. I since bought a 2nd one since they are only $200 CAD here now! The 2nd one is almost built and seems a lot better than the first in terms of incidences, aileron warp etc... plus now I know what to do to keep it light, where to re-enforce, not to overdo the ironing on the ailerons, what the incidences should be etc.

I love mine... it's 2nd best only to my 100cc Cap... it's better than my 33% Extra and my 58cc Sukhoi. And that was the old one with issues! I can only imagine how nice a true one will be.

RE: Showtime 4d snap and other problems
 

A little update. I've put the CG a bit more to the front. The snapping is less, but I'm watching it all the time. I've put a 15x6 prop back on and I do now only some precision aerobatics. Now the engine has 1.5 gallons runtime.

@crhammond

May plane also rolls a little to the right. I've only need 3 clicks of trim.


Thanks for the reply's !!

RE: Showtime 4d snap and other problems
 

My Showtime would snap at less than half throttle and low throws,the only thing that helped some was feeding in some opposite rudder during the maneuver.(opposite to the way it snapped) I ended up in a throttle off dive(like starting a parachute)several times and it snapped during the pull-out,nearly lost it. I couldnt even think about walls/parachutes down low,which is what 3-D is all about. It also rocked gently in harriers & nothing would make it lock,not spoilerons,not aileron. It wasnt dangerous but harriers look best when locked in, and landings are not good idea when rocking. I didnt have it long enough to "play" with many set ups,just CG a little bit.(lateral & for-aft were perfect). I think they all need some tweeking but the Showtime needed several things at least.(it was HEAVY too!,over 10lbs porker!) The only problem I have with the X100 is tail heavyness, and that is easy to fix.

RE: Showtime 4d snap and other problems
 

If you want to see your engine come alive start running 30% heli fuel.. Night and day difference I run 30% coolpower on all my four strokes. The fuel is your biggest engine problem.

RE: Showtime 4d snap and other problems
 

This statement is true for most planes, but not for well setup 3D planes. You should be able to do a wall from half throttle without the plane snapping on you. IF you cant then you are either too heavy, or something in the incidence or cg is not right. These planes are built to withstand some NASTY momentary G forces.



Also to the original poster. You should not have any problems hovering a showtime with a Saito 1.20. Sounds like your plane is too heavy, you need some more break in time, the engine isnt tuned right or you are not propped right. I am a bit out of touch on what the best prop for the S1.20 is, I had one but its been a year or two ago.

The showtime is made a little more like a Scale Aerobatic plane, the airfoil isnt as thick as the other planes its size so its a little less forgiving, but great for agressive 3D. You just have to know how to handle it and be on yor toes. Stay with it and you will get it. :)

RE: Showtime 4d snap and other problems
 

Hey guys,

All of my problems are solved now (the snapping, lack of power,...)

The things I've changed:
- I've put my heavy battery pack (5cell NI-MH) more to the front. First it was mounted at the rear of the canopy and now I've installed it right before the wingtube.
- I use now a 18x6 graupner-prop. Now the plane hovers very good, on full throttle the plane pulls itself vertical out.
- The snapping disappeared, I think the CG and my throttle-use made the difference. Now I never set less than 50% during manoeuvers. (In the beginning I set my throttle to idle to perform manoeuvres).


Thanks guys for your input!!!

Greetz, Koen