Waterfall CG
 

Hi,

I've been trying to do a nice waterfall with my Harrier 3D 90 but seems like something is missing. It has 45º in elevator, CG is at the point where it is recomended by manufacturer and in inverted flight does not need any alevator to keep flying straight but waterfalls are not so tight as I have done using the TOC Giles in AFPD (Aerofly) where it just pass the tail very easy. Off course every airplane is different so I guess is the airplane and not the setup.

What do you think about it?? Is there any video where I could watch a well done Waterfall??

Thanks

RE: Waterfall CG
 

try mixing in either flaperons or spoilerons at different percentages. All my planes require one or the other to get a tight waterfall. flaperons mixed at 100% you can still fly out of maneuver without flipping the switch off (assume lots of expo is also being used). with spoilerons on exiting maneuver might get a bit tough to exit with a mix of 100% without flipping the switch off but 40-60% will work without flipping a switch.

RE: Waterfall CG
 

What STG said in addition to this, really what I have found more than anything else is throttle management and LOTS of elevator throw. Your normal aft CG should get you started, but if you want really tight waterfalls without adding a flaperon mix you need a ton of throw. 60 degrees is not too much. If you have a good powerful, responsive engine setup it will do wonders as STG said. As the plane flops inverted hammer the throttle and as it falls over the tops get out, then hammer the trottle again at the bottom. This will really get them tight.
Another KEY to waterfalls is rudder control. No matter how well your plane is setup, unless it is the exception, there is nothing you can do in setup to stop the plane from wanting to fall out into a spin. THe rudder is key, you have to watch the plane and correct, especially when the waterfall is slow and just getting started. Once it builds up some speed, centrifual force will take over and help keep it straight.

RE: Waterfall CG
 

Thanks a lot for the suggestions, tomorrow I´ll try all that, I guess it has something to do with thrust as you mentioned so I´ll see what happens know that it has an ultrathrust muffler (91FX 15x4W APC).

To get more than 45º I´ll get some large servo arms because did some testing in AFPD and there is a real difference between 45º and 60º when doing waterfalls.

I´ll tell you tomorrow

RE: Waterfall CG
 

45 degrees??

Thats good for low rates;)

RE: Waterfall CG
 

how much flaperon?

RE: Waterfall CG
 

Flaperon?-- You need to be running more than 4 channels if you want to do this. I suppose next you will tell me I need a computer radio with all the mixing and expo and such....

Not sure what ultathrust you have, but mine was the little bigger one and pulled a 15x6 apc into the 11's pulling a 10 pound Spacewalker with authority. If you have the same ulta thrust as I did you might want to try a good 15x6SK wood prop. Spool will be a bit better.

RE: Waterfall CG
 

I made a mistake and accidentally posted on STG's name. I apologize for the mistake. Here is my post from above, but under my name.


What STG said in addition to this, really what I have found more than anything else is throttle management and LOTS of elevator throw. Your normal aft CG should get you started, but if you want really tight waterfalls without adding a flaperon mix you need a ton of throw. 60 degrees is not too much. If you have a good powerful, responsive engine setup it will do wonders as STG said. As the plane flops inverted hammer the throttle and as it falls over the tops get out, then hammer the trottle again at the bottom. This will really get them tight.
Another KEY to waterfalls is rudder control. No matter how well your plane is setup, unless it is the exception, there is nothing you can do in setup to stop the plane from wanting to fall out into a spin. THe rudder is key, you have to watch the plane and correct, especially when the waterfall is slow and just getting started. Once it builds up some speed, centrifual force will take over and help keep it straight.

RE: Waterfall CG
 

I agree with Mike..Lots of throw make them really nice and smooth..I have 70 deg on my EF Yak and its not tailheavy at all.

RE: Waterfall CG
 

Hoveralot,
Before you do that be sure of what your servo can handle. I am not saying do not do it, just be sure that you won't strip the servo when you do. What happens when you put on a longer servo arm is you lose some mechanical advantage. When you do this you must be sure that the servo has enough mechanical power and physical gear strength to be able to handle the load coming back from the control surface. Remember the servo is pushing the control surface, but in flight the control surface is pushing back! This is due to the winds force on that big old control surface out there while the plane is flying. As you move out on the servo arm it gets more difficult for the servo to handle the force. If the mech advantage is lost and the servo gives you can get a few things happening.
1. If its not a digital servo the control surface will physically push the servo back. and or strip the gears.
2. If it is a digital it may not get pushed back but it can and will strip the servo once you reach the limit on the servo gears, they simply break and the servo strips if they cannot withstand the load. Ask me why I know this. ;)

That is exactly why 3D folks are going to digital servos with metal gears. You go with a servo that is about 2 times what you really need and with metal gears you are ensured that the servo will hold and the gears will not strip with as long of a servo arm as you want to use. What you give up in mechanical advantage by lengthening the servo arm, you MUST make up for in the physical strength of the servo.

Now, I will tell you why I know this.
I stripped a set of Futaba 9151'sm (plastic geared digital) doing a knife edge loop last year, TWICE. I wanted to get more throw for waterfalls so I went from a 1 1/4" servo arm to a 1 1/2" servo arm. When I did I got what I wanted, BIG throws. 60 degrees plus. But when I would do a knife edge loop, at the bottom in the last quarter where you are poung the coals to the rudder and correcting with the elevator to maintain course (THWACK) the gears popped on one servo. sounded like a 22 caliber rifle. Fortunately the elevator half totally stripped and went to neutral and I landed with no problem. But I did not understand the problem, replaced the servo gears and lo and behold a few flights later it happened again. Then the light switch went off. I switched to a 333 in oz Titanium geared servo and that was it, not more problems. Of course this was in a 37% Scale plane, but you need to be sure that you take the appropriate actions for your plane.

RE: Waterfall CG
 

I read Bill Hemple's article in MAN about his Challenger Bipe and he said it waterfalls better with up elevator than with down. I'm finding the same thing with my Ultimate. Is this a "true" waterfall doing it this way?

RE: Waterfall CG
 

I dont think there is any such thing as a TRUE waterfall. The general goal is to have the airplane pivot right on the wingtube and not loop. Whether it is going forward or doing a gainer:D I would not matter. If it were part of a competitive sequence and it was required to go forward or back then I guess it would matter[8D]

RE: Waterfall CG
 

The TOC Giles is my favorite AFPD plane, too, but it is a little too easy to do 3d with. When I started to try some of the 3d moves at the flying field that I had learned with the AFPD Giles, I was really taken aback at how much more challenging it is in the real world. The Giles is also way too much of a floater. I have had to add more weight and take away some power from the Giles to get it to reflect the way my Yak flies.

RE: Waterfall CG
 

ME TOO!! I tried Reflex and G2-G3 and the same deal..much easier on the sim..The thing I still cant get is inverted harriers..the more I try to steer it around the more flopping around I get..always end up in an inverted flat spin

RE: Waterfall CG
 

LOL, No doubt... That plane gives a TOTALLY false sense of security and it totally unrealistic but it is a blast to fly. Really for me the Breitling Cap and the Extra 300S are both about as close to real as it gets. I think that the Extra is really close. There are a few things about it that are dissimilar to my plane, but generally speaking, if you can 3D well with either you can do it in the real world. I did modify the throw a little on the Extra and bumped it up a good bit to give it a feel similar to my 260. Now they are close but the sim plane flies slightly heavier than my 260, if you can believe that....

RE: Waterfall CG
 

Hey, thanks to Mike and all of you for those replies,

Mike, you probably save me from crashing this airplane because I didn`t realize what you explain about servos and long arms, I´ll better get some good servos for this job because actually it is using HS475 on elevators and those are not quite strong as a 625MG which already comes with longer servo arms and metal gears, I'll try to get some digitals but probably won`t have the money right now.

Last weekend I couln`t try anything you guys post here because my 91FX with 2 gallons of omega 10% fuel after a 5 minutes flight died on me and after landing I could not turn the prop in any direction so back to my home I took the engine apart and found the two bearings really rusty so I'll change them and try again.

RE: Waterfall CG
 

Josey,
Try using less rudder. You still need some, but that flopping thing, and having the AOA way too low when exiting a turn is from overcontrolling the rudder. Many planes are easier to harrier inverted than they are upright, as long as you know the orientations. So relax a bit, try using the ailerons and elevator to turn in inverted harrier compimented with the rudder to bring the nose around.

RE: Waterfall CG
 

Cool! I will try that!

RE: Waterfall CG
 

Hahah! Just read your post about the Futaba 9151 servos Mike and I have done the same, twice, in a 2m Capiche 140ex when on 3d rates and going into a blender i stripped two different 9151 servos in its wing long ailerons. I only used them as i had stolen them out of a pattern plane where nylon gears are fine, but in 3d they are most certainly not, not even at the mid end of the load spectrum. I replaced them with 9402's and they have been fine since, i also use JR DS8411 and DS8511 with no problem. 3D seems to really push the limit you just need the best of everything or POP! I was also amazed at the current draw increase from pattern to 3d, its significantly larger. Waterfalls seem to be one of those manouveres where some aircraft will do it with ease and others take alot more work. The Capiche as an example in its 40 size version was hard work to get good waterfalls, the larger 140ex on the other hand does it almost hands off, you barely need to blip the throttle it goes around so fast!