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HeliHobby . Ron’s HeliProz South . Century Helicopter

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Kyosho Caliber 30 & 60 - Concept - Nexus > Ballooning with Nexus
 
 
basmntdweller
Senior Heliman
Location: Indianapolis IN

I have noticed when flying my Nexus that it wants to balloon a lot when coming out of maneuvers. When I pull a hard turn and level out it wants to balloon up real bad, sometimes needing nearly full down to keep it level. After a second or so I have to back off the forward collective to keep it from taking a nose dive. Is this a characteristic of helis in general, Nexus in general or is this oddity all mine? I have a really tough time flying a smooth circuit around the field because I'm constantly fighting the ballooning.
I haven't gotten the nerve or enough in the bank to try FFF with my Fury yet as a comparison. It's day is coming soon though!
Thanks,,, basmntdweller


Stupid people have no idea how stupid they are!!!
05-11-2002 Over year old.
 
 
haleypa1
Heliman
Location: Dayton, Ohio

Also have a new Nexus and shortly will be getting into forward flight. Will let you know hwo mine does then.
05-15-2002 Over year old.
 
 
deckerv
Veteran
Location: Wellsville, NY

I did a few mods that seemed to help mine fly a lot better... I put a concept 32's swashplate on it since it has metal balls rather than those plastic ones.. and also I installed a Concept's pitch slider (the one that goes on the main mast, not tail of course) with ball bearings.. and now it is MUCH smoother. I also replaced all the plastic parts, since it was getting sloppy (the arms above the swashplate) ... All this made it fly MUCH smoother than before.
05-15-2002 Over year old.
HOMEPAGE  
 
 
basmntdweller
Senior Heliman
Location: Indianapolis IN

Yes Whirlyspud,
My elevator yoke is pretty loose. The bushings it pivots on are sloppy as hell. I have tried to find ball bearings locally but haven't had any luck yet. I thought about making some new ones from nylon but haven't got that far yet. What is your fix in that area? I just put new mixing arms on it a couple weeks ago as the last ones didn't survive my last loop. I wouldn't mind trying the concept swash but I'm trying to save enough cash for a new Caliber 30 when they get in stock here.

deckerv
I will look into the pitch slider as mine is pretty loose there as well. Most of my collective slop comes from the pivot pin in the bellcrank that drives the pitch slider. I have looked at doing something there but haven't came up with a final solution.

Thanks for the suggestions guys,,, basmntdweller


Stupid people have no idea how stupid they are!!!
05-15-2002 Over year old.
 
 
kyoshokamper
Senior Heliman
Location: HOUSTON, TX, U.S.A.

nexus/concept slop solution

Hey bsmntdweller your problem is common to the nexus and to the concept line. A weakness in the pin area just below the top front right of the main frames where a single pin holds the pivot point for both the collective and I think the aileron. It can get so bad that it starts to wallow out the hole or wear out the ball that sits inside the pitch slider itself! The answer is to find some thin 3mm washers and the appropriate length 3mm shank bolt with mostly unthreaded shank and a very short threaded end and insert it along with just enough washers to correct the slop and geometry and secure it with a 3mm locknut or preferably an anodized nut with the washer made on. If I'm correct, the upper jesus is about the right length and style. (the upper jesus is the bolt that secures the head assembly to the mainshaft, take it out and take a look) It is best to insert your washers while viewing the 2 levers from the top where in you can readily see the need for one on each side just under the hex bolt and lock nut and on on each side of the main frame. You will be correcting the extra width of the widest lever being pinched together to meet the frame. Take care not to overtighten by hand checking the lever while disconnected from everything else. There is a similar problem with the other side just below the upper main bearing on the concepts but, its solution is just to add a micro washer behind the exterior circlip. Nexus that I have seen typicall have been sold to newbies with the cheapiest s146 servos allowed. The slop and play accumulates from the servo all the way to the control surface. A helicopter can tolerate only so much of this before it starts to rebel, warn you and finally either refuse to fly or crash just for the spite of you ignoring its pleas for help. I would not fly her like she is. She has given you a final warning! Make sure you use a flybar alignment tool and don't try to substitute 2 pitch gauges unless you have to. Small Century flybar weights behind those oem kyosho paddles will help the bird in forward flight and avoid pitch up (or ballooning as you refer to it) and make for smoother fai style high speed pattern flight. I assume that you are running oem or equivalent paddles and main blades with a decent weight; because if you aren't, the pitch up could become hurrendous! Have fun and get some competent help and avoid the kyosho haters!
05-16-2002 Over year old.
HOMEPAGE  
 
 
basmntdweller
Senior Heliman
Location: Indianapolis IN

Whirlyspud,
I realized you were talking about the arm itself after I posted and later reread your post. My arm is tight on the yoke so I don't have a problem there.

Kyoshokamper,
I've been looking a several similar fixes for that pitch arm but haven't decided yet the best way to fix it yet. Your method has merit but I would like to make it as slop free as possible, maybe incorporating bearings or something and tying the pivot shaft to the opposite side frame giving more stability to the bellcrank.
I do have the KSJ paddles. They are mounted in the forward holes. Will these add to my ballooning problem?

Thanks,,,basmntdweller


Stupid people have no idea how stupid they are!!!
05-16-2002 Over year old.
 
 
kyoshokamper
Senior Heliman
Location: HOUSTON, TX, U.S.A.

pitchup/ballooning

Basmntdweller, the light thin quick ksj paddles will absolutely add to your pitch up problems by way of its reduction in the total mass of the flying disc and thereby a porportional reduction in the ratio of mass between the flying disc and the main disc. The second reason is because the lower mass flying disc now has a thinner and sharper edge on its paddles leading edge. The lighter disc now, is much quicker to cut into another plane thereby making any slop in the swashplate produce bouncing and occillating between the extreems of the limits of the slop and play during a change in the flying disc's plane of reference. You do not have direct control of the main disc, nor do you want to because of the isolation and smooth control is that which is afforded you by way of the bell/hiller mixing. The flybar is more or less directly controlled 90 degrees ahead of the intended direction and lends absorbtion of the considerable gyroscopic resistance to change by the main disc and reduces the forces necessary to effect, maintain and cease any change in the inertia of the main disc. Sorry to get techy on you, but this is important for your clear vision of the inertial and gyscopic concepts involved. Imagine spinning a steel ball on the flat kitchen table clockwise, during which you take the tip of a toothbrush and take a single try at pushing it straight ahead and away from you. You will note that it responds 90 degrees late and in the clockwise direction of rotation. That is why the flybar is 90 degrees ahead of the mainblades and no mutiblade rotorhead has a flybar! Hope this helps guy. b
05-17-2002 Over year old.
HOMEPAGE  
 
 
JEFF_SE
Heliman
Location: Pittsburgh PA

Forward Flight in WInd

Aside from the mechanical reasons for 'ballooning' there are some other things you will note as you get into forward flight:

1) As you get moving forward (faster) you will note that there is a point where the heli begins to lift without you commanding more collective. This is due to ETL - Non tech description.. disk gets better at lifting machine with a breeze under it. This is NORMAL and expected.

2) When you make a turn that ends up with the nose of the heli facing the wind... the machine will POP (balloon) and reduction of collective should be applied about 1/2 way throught the turn to get a nice flat line.

3) When you make a turn that ends up with the tail facing the wind... the machine will DROP and increase of collective should be applied about 1/2 way throught the turn to get a nice flat line.

This quirk will drive you nuts for a while, but keep working on it. The heli requires almost constant movement on the collective (very small amounts) to fly level. Before long you will know when to add or remove collective before the machine has popped or dropped.

Be sure to pay attention to your altitude as you learn to stop on fast approaches (usually in front of yourself). Depending on the wind direction and speed, you may experience "suck out". This is where you see the machine begin to fall and you end up pumping just about full collective in it to get the machine to stop falling (it what should be a hover). Get used to adding some collective when you transition from FF to a hover (ETL goes away quick).


JEFF_SE
05-17-2002 Over year old.
HOMEPAGE  
 
 
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Kyosho Caliber 30 & 60 - Concept - Nexus > Ballooning with Nexus
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