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-   -   Servo Strength's (https://www.rcuniverse.com/forum/questions-answers-154/9944616-servo-strengths.html)

rt3232 08-19-2010 07:41 AM

Servo Strength's

I have been told that with the radio on you should not be able to move the elevators up or down and if you can you have week servos, with the bird static and radio on every thing is good

I am using hs 645 mg, 1 on each elv, 6 volt 2300mah pack all heay duty wiring and switches Now with the engine running you will get some defeliction up and down both sides.

The bird flies, but is vary sensitive in pitch, Which brings the question why ?

also I have about 50% expo on the elv's

thanks in advance for your thoughts

Cheers Bob T

MinnFlyer 08-19-2010 07:52 AM

RE: Servo Strength's
If it is sensitive to pitch, you either have too much throw, or (more likely) your CG is too far back

da Rock 08-19-2010 08:25 AM

RE: Servo Strength's
Also, that much expo often makes the sticks too slow in the middle and too fast acting after half movement.

We used to fly without expo, and fly very well with some practice. So it's not exactly impossible to fly without. Continue that thought and consider flying with expo set around 20-30%.

What happens when a beginner tries to fly with too much expo is a bit complex. He gets so little feedback in flight at cruise speeds that he thinks he's getting no response or not enough response. He's not usually gentle on the stick while trying to discover how much stick is enough. Mof, he usually doesn't understand he's trying to learn "enough". So he pushes his sticks too fast, until something happens that he actually notices. When that happens with too much expo set, too much is happening when he finally see it and then darn stick is making things happen EVEN FASTER and faster. He winds up with the stick out in the area where the expo is really moving the surface and he hasn't got a hope in hades of learning any feel like that. Plus by then, the airplane's surface is beyond where it ought to be.

I've had a couple of beginners whose good buddies told 'em to use 50% or worse. Those buddies weren't flying that much expo but thought it would be better for beginners. Why? Who knows. Maybe they didn't like newbies or something. ;) I've had students learn on TXs that didn't have expo and they learned as fast as anybody. Soon as they experienced expo they were happier flyers of course, but then they were also happier with their new toy, the more expensive TX. And none of 'em found that a lot of expo was comfortable or useful.

Gray Beard 08-19-2010 01:08 PM

RE: Servo Strength's
I would go with what Mike said. The rock is correct about expo, I'm a big fan of it myself but my hands shake and I fly some very touchy planes, it helps me get them straight and level before I go into a stunt. Last week I removed a bunch from a pattern and IMAC plane ailerons because they were a bit sluggish. Rudder I never put any in and elevator not too much. Don't go by this, these are my normal expo settings, pilots need to find there own. aileron 60% elevator 35% and that was just for these two planes. Today the ailerons are down to 30%. Some planes I don't use it at all. I like expo on my throttle but it's to make it more sensitive not less. Like rock mentioned, it can help you or bite you, it's something you have to figure out for yourself from plane to plane.;)

rt3232 08-19-2010 08:32 PM

RE: Servo Strength's

First this bird was balanced with a vanessa rigs, so I am sure it is ok also if you fly a45 deg up line it just keeps going and if you do the same inverted it flys the same way. it does fly hands off stright and level.

next this is a 3d bird but due to good old (arther-I-tus) I am good to just get arround the patch with a roll or 2 and if lucky a loop, any way this is my first bird with expo do to the vary large elevator surfaces so will take it down to 15% and see if the stiff/shak'y hands can handle it.

And again Thanks for you input

Cheers Bob T

j.duncker 08-19-2010 08:40 PM

RE: Servo Strength's
Hi Bob T

If it is a 3D model and you are not flying 3D with it then I would move the CG forward a little. Some 3D models come with a CG recommendation that is the "as far back as you dare go" setting.

A 3D model with the throws reduced some expo and a SLIGHTLY forward CG is a realy relaxing model to fly as it is unlikely to tip stall whatever you do to it and everything happens quite slowly.

I bet with your current CG you could do quite tight loops on the trim alone.

Part time 3D HOOLIGAN :)

MinnFlyer 08-20-2010 07:23 AM

RE: Servo Strength's
Ditto to what j.duncker said

w8ye 08-20-2010 10:23 AM

RE: Servo Strength's
If the plane over reacts in pitch, it is a sure sign of the CG being too far back especially at landing flare out time

Put some weight in the nose and see how it flies and if you like it or not?

da Rock 08-20-2010 03:57 PM

RE: Servo Strength's


If the plane over reacts in pitch, it is a sure sign of the CG being too far back especially at landing flare out time

Put some weight in the nose and see how it flies and if you like it or not?

Actually, it's a good idea to do a couple of CG tests before you start adding dead weight. There are a couple flight tests that show tail heavy pretty quickly. If it doesn't show tail heavy in a dive test or the amount of elevator to hold inverted suits you, then all you need to do is shift the elevator rigging. Move the connection one hole out on the elevator horn. The testing takes a minute, and moving the pushrod another two. And you wind up with an awesome flying airplane.

jester_s1 08-20-2010 04:19 PM

RE: Servo Strength's
Sounds like the controls are just too hot. If you set up some dual rates I'll bet it calms right down like you want it to.

rt3232 08-21-2010 07:17 AM

RE: Servo Strength's

Well about the C/G with the bird in the vanessa rig and stablethe (book calls for C/G @ 5 1/4 back from the L/E at the fuse, mine is @ 4 7/8 plus 1/2 of the tank is fwd of the c/g

About flying loops are a bit tight if you just jam fuul up, probabley 50 ft. dia when you fly it thrugh you camake them as big as you want and they do repeat. Landings are a breese stall or wheel.

It will be sunday befor I can try any of the suggestions, so the plan is

reduce the expo first

Then add stick on weights (will try 2 oz ant a time)

One outher thing from the book control movment chart on the ailerons about 70 % , rudder 100 % elevators 25 % trying to make a 3D bird into a mild sunday/sport flyer do to the arthritic

and agine THANKS for all of the input

Cheers Bob T

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