7snakes

I have a Nexstar with a CVS cam mounted inline with the cg on the left side of the fuselage under the wing. I have it pointed to the front of the plane and the cam is mounted upright with its edge attached to the fuse. It protrudes apprx. 3 inches from the fuselage. Flight characteristics of the plane have been flyable, but challenging to say the least. Trying to bank to the left usually results in the plane failing to turn and it goes nose up into a steep climb.( Basically almost hovering) Banking to the right does not give problems. I tried to compensate by programming in down elevator with a left bank and the plane generally makes a decent left turn. Maybe it was just the wind direction or speed causing the problem? Or is the left wing stalling from the drag created by the camera? What in all likelyhood is happening? If I mount another cam in the same fashion to the right side , will I get the same failure to turn? What if I have a cam on each side? Will the effects cancel each other and I not have a problem banking, or will I not be able to bank in any direction? Could the problem be one of just cg issues laterally? I have gotten some ok footage with these cams when they are mounted flat up against the fuse videoing straight out to the sides. The plane flies fine without any cameras. It flies fine with 1 or 2 cameras on each side if they are mounted flat up against the fuse. I know it wouldn't be laterally balanced with 1 camera on the side-still it flies fine.(trying to get forward facing video) The problem arises when the cam is mounted on its edge facing forward. It is like I have no aileron response to turning left. I programmed in some down trim to the elevator when banking to the left with a switch on the tx. It seems to help considerably. Banking to the right is not a problem. I want to try forward facing cams on both sides at the same time, but am hesitant I will not be able to control seeing how the left sided mount worked. If it was a cg issue, wouldn't it present problems with the cams also mounted sideways flat up against the fuse? (no-it flew fine with 1 or 2 mounted this way. It just seems to not want to turn left and the nose rises so the plane appears headed for a stall.
Another thing I was thinking. In straight flight air moving over and under the left wing is really only being deflected on the underside by the camera. When input is given to bank left, now 2 surfaces are protruding on the left wing-a.the aileron is going up and b. the camera under the wing is down(2 projections, 1 above the wing and 1 under) The right wing only has 1 projection in the left bank and that is the aileron going down.

Montague

Sorry, I'm having a bit of a problem following what you are saying. Do you have some pictures of the camera setups, what works and what gives you trouble?

Also, when you turn, are you using the rudder and coordinating your turns properly? The nextstar doesn't really have excess vertical area, so it is really helped in the turns by proper use of the rudder.

The CG being a bit off to the side shouldn't cause too much trouble unless it's REALLY far out there.

I suspect you are having problems with drag on the one side combined with the drag caused by the ailerons, but I'm not sure. You might try using dual aileron servos and programming in 100% differential, so that the ailerons only move up and not down at all. This should reduce (but not eliminate) issues with something hanging off the bottom of the wing in the airflow. Maybe, I'm not sure.

If you want forward facing video, how about mounting the camera on top of the center of the fuse? direct the exhaust down and to the side, that's what guys here who have forward facing cameras do.

opjose

The way he has it mounted... it sounds like the camera is killing lift on the part of the wing area it is mounted on while adding to the weight of the plane...

I would do what Montague suggested... move the camera onto the fuselage.

ksechler

3 inches! Hold your hand out of your car window. See how much resistance it creates? That's exactly what your doing to your 5 lb plane with the camera. It is creating a ton of drag and flow separation behind it. On top of that, it is off center. I'm not surprised the plane flies terrible.

VFR_RC

What's confusing me is that if the camera is on the left side and when he banks left the nose goes high... if he was losing lift or the drag was holding the left side, wouldn't it try to go into a spin when banking to the side the camera is on? shouldn't it drop the nose when banking left? (since there's no obstruction on the right side and the right aileron is increasing the angle of attack the right wing produces way more lift and thus starting a spin).

Like Montague said, some pics would help understand. Also a video taken from the plane when this happens

Montague

Maybe, but maybe the camera on the left is causing a large yawing to the left. This is then countered in level flight with lots of right-trim on the rudder and ailerons, maybe mostly in the rudder, so it can fly a straight line at all.

Then, when the plane is rolled left, the plane still has a lot of right rudder in, which results in a hard slipping turn, espeically if no rudder is used to coordinate the turn. This will look like the nose pitching "up", when it's really more a yaw to the right combined with a slight pitch up. Basically adverse yaw on steriods.

I'm guessing though.

jetmech05

look at it this way...you know you have a ton of drag on the left side......when you turn left you naturally kill lift on the left side combined with the induced drag of the camera and your in a stall or just above a stall the tail tends to settle just before a full blown stall.
Its just like a twin engine aircraft (props) with an engine out, (unfeathered prop) never turn into the dead engine. the dead engine is drag and then loosing lift on the same side while in the bank, you probably won't get to do that more than once. I know of at least one full scale aircraft that did it, just once and killed all aboard. Rudder won't help.
I suggest, for pictures facing forward, build yourself a cradle to mount the camera at the center of the wing on top. it can be secured with rubber bands. Still a bunch of drag but its centered on both wings. plus it can be tested on high speed taxi before you lift off.
Have fun and good luck

7snakes

I appreciate the responses. Will try to upload some pics of my setup tomorrow. When flying with the protruding camera, I have not changed aileron or rudder trims. They are still set as they are for normal flight without the cams. Flying with cams mounted flat against the fuse and facing to the side has not created any problems. Problems seem to arise only when the camera is facing forward. Will try again, but 1 time awhile back I tried mounting the cam on top of the wing over the center of gravity. The cam was standing upright and mounted with velco and a brace behind it. It was all I could do to get the plane around 1 time and back safely on the ground.
(link to video of 2 cameras mounted flat.)
http://www.youtube.com/watch?v=S5_RPc4fU9E

jetmech05

you dont have the problem with the camera against the fuselage because you dont have that big air brake under the wing, in other words you don't have as much drag.
by the way for around 100 bucks they were selling a 9/16ths inch square camera that sent signals to a receiver that hooked up to a tv/vcr/dvd whatever good quality video. now this was a couple of years back check it out before you loose your plane and your camera.
if you dont want to do that and the camera didnt work on top the wing how about slingging it from the gear.

VFR_RC

Yup. jetmech05 is right. For some reason i thought the camera you were using was something like [link=http://cgi.ebay.com/WIRELESS-PINHOLE-CCD-CAMERA-PORTABLE-DVR-USB-RECORDER_W0QQitemZ140125579086QQihZ004QQcategoryZ4 8632QQrdZ1QQcmdZViewItem]this[/link]. Ths one you are using is way too big to mount facing forward. It will be a huge air brake and it will act as a flap when you turn left and your right aileron is also in "flap" mode (meaning it's increasing the angle of attack).
From your video i noticed that [link=http://www.camcorderinfo.com/content/CVS-One-Time-Use-Video-Camcorder.htm]this[/link] is the camera you are using.

The camera from the ebay link is nice since it has a rechargable battery in it, so you can mount it anywhere in the airplane facing forward with minimal drag and without running cables for power.