Hard mount or soft mount the camera?
 

I have been taking some pictures from my LT 40 using a Minolta 35mm camera. The problem is that most of the shots are blury, but a few are perfect. I'm certain engine vibration (2 stroke) is causing the blury pictures but idling down before the shot doesn't seem to help much. To be honest, it's kind of a flimsy set up made from 1/8" lite ply and other woods. Would it help to have the camers mounted more solidly to the plane, or soft mounts with rubber gromets and such?

Thanks,
David

RE: Hard mount or soft mount the camera?
 

Put foam between the camera and the plane. Next, get an APC 11X4 and keep the rpms up. Idling shakes the plane more so than a high throttle setting.

RE: Hard mount or soft mount the camera?
 

The simplest fix is to make sure your prop is balanced. Using a wood prop works well since they tend to be lighter in weight and therefore less rotating mass available to help cause vibration. You want to reduce vibration as much as possible at the source first. Some motors tend to vibrate more at certain throttle settings as well. If possible, use a smaller engine with just enough power to do the job well. Most r/c planes are overpowerd to begin with as a way to compensate for poor pilot skills. haha...A soft mount for your camera will help but be careful its not too rigid to where it just transfers engine vibration. Soft foam used for mounting r/c equipment works well as does the material used in stress balls.

RE: Hard mount or soft mount the camera?
 

What sort of camera is it, can you vary the exposure? If so open up the aperture which will require a faster shutter speed for any given lighting/film combination. If you can't vary the exposure but the camera is fully automatic, use a faster film eg 400 asa instead of 100 asa. (Do all the prop balancing stuff anyway as it's good practice with or without a camera)

RE: Hard mount or soft mount the camera?
 

Is it possible to use a digital Camera, I am not sure how to fire the shutter, any ideas.

Peter

RE: Hard mount or soft mount the camera?
 

Thanks guys for the ideas. I'm going to rework my mount and try again, and I'll also try different props.

electricpete- I just have my camera mounted to some plywood, and a mini servo rigged up to press the button.

RE: Hard mount or soft mount the camera?
 

Yes, what Randall1959 said.

It's easier to dampen high frequency instead of low frequency. Listen to the Moron's Stereo 6 cars away at a stop light. The low frequency still gets through although the high frequencies are absorbed. However a good mount should allow you to get away with slower RPM's too. You can do everything right to get rid of as much vibration as possible, but running a single cylinder engine means you will still have some vibe you can’t get rid of. You need to do one and possibly two things. First is to isolate your camera from the airframe. Use some C channel made up of wood and slide your camera mount into it. Use ¼ inch latex foam lined in the C channel so it’s folded over and the mount rides in the fold. The latex foam used for padding RC electronics has great visco-elastic properties. Thats what you want. Squishy not bouncy. Do this in a couple of places but be careful. Too tight a compression is too firm a mount. Also, too much surface area is no good. The more foam and mount you use to isolate with, the stiffer it becomes. Now the second part. (Test fly first before doing this part to see if you need more help) It’s a little counter intuitive until you think about it. You may need to increase the inertia of your camera. Think about this. If the camera and mount are really light, (That’s what we strive for) the soft mount isn’t all that soft. The vibration transfers easily from the airframe, through the foam and to the lightweight little camera. It still moves pretty easy. If we add weight to the mount, like taking small amounts of the hobby stick on lead, (Use super glue too so it's really secure) and tack little pieces around on the mount to increase its weight and resultant inertia. Now as the vibration occurs, it compresses the foam but the camera is heavier and resists going into motion. You need to speculate a balance. A glow engine is pretty high frequency and low amplitude on the scale you’re flying. Even if idled down. You don’t need to absorb slow big motion. You need to absorb fast little motion. You may not need to add the weight then if you keep the mount soft enough. Also, build the mount so that the soft attachment points are around or on the axis of the camera sensor. The sensor in motion is what causes the blur. Take a ruler and hold one end. Wag it in the air and envision the sensor is at the far end. Lots of motion. Keep wagging it and envision the sensor is in you hand. It doesn’t move nearly as much. A little goofy illustration perhaps but you get the idea. Just don’t soft mount around the lens and let the rear of the camera swing. Mount around the rear or sides of the Camera. It's best if you can keep the mount soft and mount from the front and the rear.

Dan