Two newbie questions (non-obvious)

I'm interested in doing digital photography from an RC model airplane, and have a couple of questions that I can't find answers for on the web after a few days of searching:

  1. How much surplus lift capacity do typical .40/.60 trainers have? Is there a way to calculate this from plane specs? The camera I have in mind, Pentax Optio-S, is only about 3.5 oz, plus about 1.3 oz for one servo (miniumum control: shutter release). If I hung this right at the CG, would the plane get off the ground?

  1. I can't quite figure how the "extra" channels on 6-9 channel radios are translated into knobs/switches. It _appears_ that, for most radios, channel 5 is an on/off switch, and channel 6 is a proportional knob. Right? But what about channels 7-9? Are these _all_ on/off switches, or are some of them on/off/on (-100,0,+100) switches? (Think of the other possible camera controls: Tilt angle from horizon (proportional); zoom (wide, off, tele), power (press on / press off), etc.) What do I look for in transmitter specs that will reveal the kind of switches/knobs used to control these other channels?

If convenient, I'd appreciate a reply to my email: snipped-for-privacy@tufox.com

Thanks!

Jim.

Reply to
Jim
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In article , Jim wrote: | I'm interested in doing digital photography from an RC model airplane, | and have a couple of questions that I can't find answers for on | the web after a few days of searching: | | 1. How much surplus lift capacity do typical .40/.60 trainers have? | Is there a way to calculate this from plane specs?

Not really. It will vary based on so many things ...

| The camera | I have in mind, Pentax Optio-S, is only about 3.5 oz, plus about | 1.3 oz for one servo (miniumum control: shutter release). | If I hung this right at the CG, would the plane get off the ground?

But 5 oz is probably just fine. Most 0.40 and larger trainers can handle the extra weight (but DO put it at the CoG!) ... performance will be down somewhat, but that's probably ok.

| 2. I can't quite figure how the "extra" channels on 6-9 channel radios | are translated into knobs/switches. It _appears_ that, for most | radios, channel 5 is an on/off switch, and channel 6 is a | proportional knob.

Varies from radio to radio. But what you've described is pretty common.

| Right? But what about channels 7-9? Are these | _all_ on/off switches, or are some of them on/off/on (-100,0,+100) | switches? (Think of the other possible camera controls: Tilt angle | from horizon (proportional); zoom (wide, off, tele), | power (press on / press off), etc.) What do I look for in | transmitter specs that will reveal the kind of switches/knobs | used to control these other channels?

Usually what you do is hook up a servo to that channel and start moving knobs, see what happens.

Note that for every channel you use, you'll need another servo, and some hardware to make that servo control whatever control you want.. Most people who put cameras on their planes only control one thing -- the button to take a picture. The other things are just too much to worry about up in the air.

Be sure to keep the camera out of the exhaust, or it'll get coated with slime almost immediately.

| If convenient, I'd appreciate a reply to my email: snipped-for-privacy@tufox.com | | Thanks! | | Jim. |

Reply to
Doug McLaren
  1. How much surplus lift capacity do typical .40/.60 trainers have? Is there a way to calculate this from plane specs? The camera I have in mind, Pentax Optio-S, is only about 3.5 oz, plus about 1.3 oz for one servo (miniumum control: shutter release). If I hung this right at the CG, would the plane get off the ground?

  1. I can't quite figure how the "extra" channels on 6-9 channel radios are translated into knobs/switches. It _appears_ that, for most radios, channel 5 is an on/off switch, and channel 6 is a proportional knob. Right? But what about channels 7-9? Are these _all_ on/off switches, or are some of them on/off/on (-100,0,+100) switches? (Think of the other possible camera controls: Tilt angle from horizon (proportional); zoom (wide, off, tele), power (press on / press off), etc.) What do I look for in transmitter specs that will reveal the kind of switches/knobs used to control these other channels?

If convenient, I'd appreciate a reply to my email: snipped-for-privacy@tufox.com

Thanks!

Jim. ================================== One of our club members has used a Great Planes PT-40 as a camera plane for a few years. He uses an OS 46 FX for power and has no problems taking off a grass field. He uses a cheap 35mm camera with autowinder for the film, so I'm pretty sure it weighs more than 3.5 ounces. Some of the photos are at

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I 'think' your info for 5 and 6 is correct for a 6 channel radio. A high dollar 9 or 10 channel radio probably can go fixed or proportional for all or most channels and should allow you to assign the channels to switches and knobs as you please.

Reply to
Carrell

In my experience using a camera on board my Ben Buckle Falcon, carrying it and mounting it is not a problem. I used a £20 Olympus camera from Argos selected really for the position of its shutter release button which must be one which you can operate using a servo. See here for pictures of those details

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However, what I did find was that the Laser 70 motor produced too much vibration for clear photos with power on. If anything it was worse with the motor ticking over. I found that taking pictures after killing the motor gave excellent results.

So for future aerial photographs I will be using an electrically powered platform simply because you can re-start the motor whenever you want. In any case I imagine thta there will be far less vibration on an electrically powered aircraft.

If you do a little Internet searching you will find some first class aerial photography sites for modellers. These carry all the information and help you will need.

Reply to
grapher

Your plane won't notice the weight. The extra drag may be slightly noticeable. Make sure to mount the camera away from the exhaust or it will get oild real well!

For the extra channels, ou will need to look at each individual transmitter as there is no standard. It could be switches, sliders or knobs. Most of the extra channels are used for mixing.

Reply to
Paul McIntosh

Since you are a newbie, I would suggest that you get a trainer and learn to fly first. During the course of training you will obtain the knowledge you desire about phase two of your project.

Dan Thompson (AMA 32873, EAA 60974, WB4GUK, GROL) remove POST in address for email

Reply to
Dan Thompson

re: 1.

My gut feel tells me that most .60 trainers could carry an extra pound without breaking a sweat. I would say that a typical .40 trainer, say an LT-40 wouldn't even be offended by an extra 3/4-1 pound at the CG. They have a lot of wing area and with the rectangular wing planform helping avoid tip stalls though I doubt they would rear their head at the weights and wing loadings we're talking about..

Look at the numbers: A SIG LT-40 has 900 sq. in. of wing area, aka 6.25 sq. ft. The top weight listed in the specs is 6 pounds. At that weight the wing loading is 15.4 oz./sq. ft., which is very comfortable.

Add 1 pound, you are still only at 17.9 oz./sq/ ft/ which is also considered moderate.

With a .46-ish 2-stroke or .70 - .72 4-stroke on an aircraft like this you should be just fine with your payloads.

Mike D.

Reply to
M Dennett

Shoot, I put a cheapo 35 mm self wind with a shutter release servo, in a lazy bee with a OS .15fp, and it did just fine.

I did find that I could not get clear pictures without shutting the engine down. I agree that an electric would be better, using stops and restarts.

Reply to
Morgans

Did you try shock mounting the camera? A good bedding in foam will stop the transfer of engine vibration. Or so I have seen on videos and other stills from IC powered birds.

Reply to
Six_O'Clock_High

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Chuckle!'

As well as I could. As you can imagine, there is not a lot of room in a lazy bee for a camera "and" a lot of foam.

Plus the fact that it took a good bit of throttle to keep it in the air.

Reply to
Morgans

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