aerocharger

Well, I finally had my Caliber 30 set up for its initial flight. (or so I thought) I've had tons of practice on a Hirobo XRB and a Kyosho M24 EP in my house and on PC simulators, and I was confident I'd be able to handle the helicopter. I am thoroughly familiar with how the helicopter works and checked everything three times. On my first liftoff, I found that no matter how much right rudder I gave it, the helicopter would spin around to the left. At first I thought the gyro was backwards. Checked it, it was fine. I even reversed it to make sure. Still the same problem. Then I checked that the linkage was allowing full travel to give me maximum pitch. It was, and I readjusted my trims and end points to make sure. I had full travel in both directions, but most importantly in the direction I needed. Still the same problem. To make sure it wasn't the gyro, I even disconnected the gyro completely. Still the same problem. I am using a rotor speed of 1,700 rpm according to my GV-1 governor, and yet, still no matter what I do, even with the rudder at full right, the helicopter turns left. Should I try a faster RPM? Has anyone else had a problem similar to this with the Caliber 30? Of course, in trying to figure out what was wrong, I turfed it and have to rebuild it now, but I would really like to get this thing under my control.

Very frustrated...
A.C.

TMooreATX

I don't think that statement applies here. You missed something. I've set up at least 30 of these machines and can tell you that something isn't right. Is the tail rotor rotation in the right direction? Are you absolutely sure you have the machine set up right. What radio and gyro are you using?

Get some local help from an experienced pilot. That's the best way to solve this problem.

TM

BarracudaHockey

My Feedback: (11)

If the caliber is a belt drive, which I believe it is, make sure you don't have the best twisted too many times. Also make sure the blades are rotating it the correct direction that that would be looking at the heli from its right side the tail should be turning counter clockwise.

aerocharger

Thanks TMooreATX,

Without setting up 30 of these machines I can tell you that something is wrong here too... That's why I posted this message. Unfortunately where I live there isn't much of an abundance of people who fly these things, so for the moment, this seems to be the best place for me to at least get some ideas.

I thought the tail rotor might be spinning in the wrong direction, but I checked it and it is ok.. I even tried to apply left rudder to see if it would turn the other way, and the helicopter just spun around to the left faster. Holding right rudder slowed the spinning but didn't stop it.

The gyro is a Futaba GY401 and the Radio is a Futaba 7CHF 7 channel heli radio.

Thanks,
A.C.

echobot

I have a Caliber 30 and never had any problems like your having. When you installed the belt drive for the tail did you twist it the correct way? Also, I would check to make sure the servo arm is installed in the correct position up/down.

I know the manual for the Caliber is a little confusing, so I would go back and read the gyro setup section again.

Like everyone else had said there is something you are missing.

Good Luck

TMooreATX

It sounds like the gyro may be out of trim, badly. Set it up in rate mode so that nose stays straight. Disable all revo mixing and make sure that there is no t/r subtrim active. Once you have it hovering in rate mode than switch to AVCS. There should be just a slight amount of pitch in the tail blades when it is hovering. If you are looking at the tail blades with the canopy forward the pitch should have the leading edge of the blade pointed toward you and right should increase pitch, left should decrease pitch.

Make sure you are in AVCS mode when you boot up the RX pack.

TM

ltriska

my 2 cents, is the belt tight enough not to slip ?

aerocharger

Thanks everyone for your ideas. I am in the process of rebuilding the tail section which sustained the bulk of the damage in the crash. I will definitely work on making sure the gyro is configured properly, but there is a distinct possibility that the tail rotor belt might have been slipping. Unfortunately, since the tail gearbox broke, I couldn't go back and check it. That would seem to make the most sense though; if everything else was working the way it was supposed to, but the tail rotor belt was slipping, then the tail rotor was not spinning fast enough to have the proper authority.

Thanks,
A.C.

Calbr30flyr

Did you, when you initially setup the tail servo make sure the servo was neutral (no imput to the control while on and also the subtrim on the controller was 0 or whaterever the setting might be for middle im not familiar with your transmitter) then put the servo horn on with the tail push rod in making the tail rotors a bit tilted to counteract the force of the torque of the engine and motor. Check that the gyro is set right and not reveresed. While the heli is setting on the ground turn the main rotors clockwise and check the the tail rotors are spinning counterclockwise. I hope this can help you and that you can fix your heli so you can enjoy the performance of the caliber 30 Best Regards,
John

aerocharger

Hi Guys,

The weirdness continues...

I rebuilt the helicopter with a new tail gearbox and a new belt, double checked everything again and then set the helicopter into a little test stand I made for it which allows me to run it without worrying about it flying away. The stand allows me to yaw the helicopter to observe the tail rotor response.

I have full travel of the rudder servo and tail rotor blades, and yes, they are turning in the correct direction and the linkage is traveling in the correct direction, etc. What I observed this time around is that as the rotor rpm increases up to its normal speed of around 1,700 rpm, the tailrotor linkage stops moving to its full travel, and only moves about 1/8th the total travel as it does when the engine rpm is low. This only seems to happen due to rpm, not stick travel; in other words, if the engine is in idle hold, and I move the throttle stick all the way up, I still have full rudder travel. It's not a gyro problem because I disconnected the gyro and the same thing happens.
So, since the problem seemed to be caused by rotor rpm, I thought it could be one of two things. Either the servo does not have enough power to move the blades against the rpm load (it is the digital servo that came with the gyro, so it should be able to) or it is an electronic problem, perhaps related to interference caused by the rpm signal of the governor speed sensor. I ruled out an electronic problem because I disconnected the tail rotor linkage, spooled the rotor up to max rpm, and observed full travel of the servo. So it must be a mechanical problem.
Could it be a problem with the servo? It is a brand new servo that came with the Futaba gyro, and I don't think it should have a problem.

Any ideas?

Thanks,
A.C.

BarracudaHockey

My Feedback: (11)

Did you inhibit Revo mixing?

Never assume brand new = automatically good just less likely to be the cause.

echobot

AC,

Well you could replace the digital servo with a standard servo to see if your problem goes away. Just make sure you set the gyro for a non-digital servo if you do.

aerocharger

Ok, well I replaced the tail rotor servo horn for a shorter one, ran it up on the stand and it seemed to work. Then I took it outside and took off into a hover, and after I trimmed everything out, the tail was rock solid. I didn't get a chance to do much flying because it was really windy and I don't have a lot of room for error in my back yard, but the heli seems to be working after I made that change. I can't believe that a 1/4 inch difference in the length of the servo horn is enough to make a difference.

Thanks everyone for your help and ideas. I think the problem is solved.

A.C.

BarracudaHockey

My Feedback: (11)

13 to 17 millimeters from ball center to spline center seems to work best. Anything longer and your loosing resolution of the gyro. That would make sense. Keep us posted.