A couple of questions.
 

This is my first post. I haven't even seen an RC plane in real life, only pictures and vids. But I have been looking at getting into it.

I'm studying Aerospace Engineering in Australia so I'm gradually building my knowledge of the electronics involved.

My aim this year is to get some lessons so I can fly one then build at least one basic plane. And depending on how that works out getting some 2 way telemetry happening (wireless video, airspeed indication, potentially GPS, etc.) The reason for this is that I aim to contribute to our university's UAV project for my thesis in final year.

So I have some questions.

- What range can I expect from a typical trainer transmitter? Does weather and LOS affect it?

- When you buy an transmitter will it come with everything you need like: reciever, servos, powerpacks etc.

- What frequency do most transmitters operate on? Can you change to multiple different channels if there is interference?

- When buying a glow engine do most come with everything you need such as fuel tank, tubing, etc.

- What is the best/cheapest way to get glow fuel.

- How do you know what size engine to buy?

Think that should get me started.

Thanks
dy

edit: here's one more i forgot

- how much flying time could I expect from a tank of fuel? how long on average to servo/reciever batteries last?

RE: A couple of questions.
 

Pretty much as far out as you can see to fly the model, you don't usually run out of range before you can no longer see it well enough to control it.
Most TXs do come in complete packs like this, but you can buy things separately as well
There are certain freq bands for each area of the world, here in the US, 72MHz band is the most common. RXs can typically change freqs by just swapping out a xtal, TXs typically need to be sent in to be retuned to a new freq, unless you get a radio with a separate RF module (like the Futaba 9C), or if you get a synthesized TX or module you can tune any channel within the band by setting some switches/dials.
No.
Join a club that buys it in bulk for its members.
The kit or ARF you buy will recommend a size or range of sizes for it.
This all depends on what fuel tank size and batt capacity you chose to install in your plane... I typically try to install a tank that will give me at least 10min flying time, and batts that will last at least 5 flights. The last plane I built would probably fly 20mins and the batts lasted about 10 flights. Larger tanks and batts mean more weight, which adversely affect performance, so it's best not to get too crazy with the batt and tanks sizes. After 10mins or so of flying, I'm usually ready for a break, and in a day at the field, I will only get in about 5 -10 flights max.

Hope that helps!

RE: A couple of questions.
 

The starting point for finding out engine is the overall weight of the plane without fuel. A standard trainer plane weighs 5 to 6 lbs. and will fly with a 40 size engine. For more performance most flyers go one size bigger which is a 46 because the price and weight of the engine are pretty much the same but you get more power. For a 10 minute flight for the 40 engine with a bit of reserve you would go with a 8 oz. fuel tank. For the 46 engine you should go to a 10 oz. tank. The typical prop size for a 46 engine would be 11" long with a pitch of 6. This is called a 11-6 prop. Any other questions feel free. [8D]

RE: A couple of questions.
 

dydx,
First, welcome to RCU. You'll get a lot of decent advice from friendly people.

OK, Range: expect 1/2 to 1 mile from most standard radio equipment today. I haven't noticed any impact by losing sight of the plane. (I've recovered when going down behind trees, but you have to be lucky! ;) ) As for weather, if the plane was water-proofed to prevent the electronics from getting wet, and you had a method to keep the transmitter dry, weather shouldn't be an issue.

Radio packages: virtually every transmitter (Tx) comes with 3 or 4 servos, one receiver (Rx), battery packs for Tx and Rx, and slow charger, a switch harness, and one servo extension. As has been said, you can buy stuff separately as well.

Not sure what frequency is used in Australia, but someone will chime in. ;)

Engines only come with a muffler and a glow plug, but not all engines even come with those. Make sure you know what you're buying. That being said, if you buy an Almost Ready to Fly (ARF) trainer, or a kit, they usually will have the fuel tank, wheels, and control hardware. You will need to buy fuel tubing, as well as all the related equipment for starting and running the engine. (Fuel pump, glow plug ignitor & charger. A 12 volt starter is a good idea, but not absolutely necessary.)

There's really no "cheap" way to buy glow fuel except shopping around. If you're lucky enough to find a club or group of guys that buys in bulk, that's certainly cheapest.

Engine size: As was mentioned, kits or ARF's will have a recommended range of engine sizes. I recommend buying one at the top end of the recommended range. .46 two stroke, or .52 four stroke is about right for the typical "40" size trainer.

Flying time: as pkh said, depends on some things. Typical 40 size trainer ARF or kit, will usually have either an 8 or 10 ounce tank, and give 10 to 15 minutes flight time with a 46 size two stroke. A 52 four stroke would get you closer to 20 minutes on that smae fuel.

The battery pack that come with your Rx (600 mAH) will get you about four 10 to 15 minute flights before recharging, but it's recommended that you check the pack's voltage between flights with an "Expanded Scale Voltmeter" (ESV), which is a tester that puts a load on the pack for a truer reading. (Can be bought for about $15 U.S. at a hobby shop.)

The Tx pack will likely last for a full days flying.

Larger capacity packs and larger tanks will extend flight times of course.

Feel free to ask questions.
Dennis-

RE: A couple of questions.
 

Hi,

Good answers above,

I would add only this; Fuel, glow fuel is about 12 to 14 US dollars per gallon when purchased at a hobby shop.

I am rather suprised that someone studying aeronautics hasn't spent thier life building and flying model airplanes.

Building UAV's in the manner in which you are proposing has become fairly commonplace and can be built almost entirely from "off the shelf" components. I don't know how impressive your thesis would be considering it is little more than purchasing consumer products and assembling them. It seems like a dead thesis walking to me.

However, you can gain a very valuable and practical understanding of airfoils which is far beyond thier qualities and quantities described in text books. And you can actually gain experience using new materials and new constuction techniques. I do believe a modeler has a clear advantage over a non-modeler, ( if there is such an engineer). So I believe modelling will help you, but I feel you might keep an open mind about your possible thesis .

RE: A couple of questions.
 

I'm not so sure about that... there are a number of "consumer products" that would make constructing a UAV easier these days, but integrating all of these gadgets (GPS, gyros, accelerometers, and other types of sensors) with an embedded microprocessor or microcontroller system (small enough to fit in a model), and writing and debugging the controller code could still be a daunting task for just one person, depending on what the UAV is supposed to do. Not to mention developing hardware and code required for more complex functions like target identification and tracking... which would require some sort of digital video system and pattern recognition code. All of this would have to be field tested in the debugging process, and would likely involve some crashes and rebuilding of planes and equipment... time and $$$ intensive....

The UAVs that I've seen on the web (at least the one's that actually did anything interesting) were assembled by teams of engineering students, not just one guy.

RE: A couple of questions.
 

Thanks for your responses everyone.

Firstly I hope that hobby stores in Australia work with metric units because I have no idea what an ounce weighs and how much a gallon is.

- I was wondering if anyone has any close up photos of a reciever unit. Having never seen one I was wondering how they connect to the sevo's and power and what the "ports" look like.

- Also, is the power to the servo's usually centralised at the reciever?

- Is it possible to interchange servos? Whatabout recievers....if your reciever dies do you need to buy a new transmitter as well?

this is the first time I have had the financial means to have a serious go at it. Modelling isn't really popular in our community as well (which sucks) the nearest modelling club and hobby store is a fair distance from where I live.

I didn't make it clear. Our final year projects/thesis are team based.

the course I am doing is entirely avionics based. We are primarily concerned with control systems. We are expected to be able to design those "of the shelf" components from scratch. The main goal for this year is to program the UAV to take off and land BY ITSELF [X(]. A daunting task. Remeber also that it's only a bacelor level thesis. We are not expected to do something that's never been done before.

This is the site. CHeck it out.
http://www.bee.qut.edu.au/projects/q...rgraduate.html

RE: A couple of questions.
 

Some web sites of radio systems and components
http://www.futaba-rc.com/index.html
http://www.hitecrcd.com/
https://www.fmadirect.com/site/home.htm

If you do visit a local hobby shop, they'll probably talk about size, weight, etc in metric units.

RE: A couple of questions.
 

dydx (do you have a calculus fetish?[:D)

Does the Q in your address mean that you are in Queensland? Depending where you are there are a number of clubs and hobby shops where you could get a lot of the answers you need.

I learned to fly in Brisbane (Tingalpa Model Club) without needing to own a model by paying for instruction. I just turned up and stirred the sticks, this arrangement suited me fine at the time, and no cleaning up after!

There are also clubs and hobby shops in other parts of Queensland, and most places welcome newcomers. Whilst you can get a lot from this forum it cannot replace getting out to somewhere people are actually flying.

Terry

RE: A couple of questions.
 

I was thinking of going there this weekend to check it out actually! ( I guess they fly every weekend....... Sat and Sun??)

Could you tell me how much cost for lessons. And whether you need to commit to membership or anything like that to get lessons.

RE: A couple of questions.
 

Here is a uav/rc telemetry link you might find interesting...
[link]http://www.rcatsystems.com/[/link]

also,
1 ounce = 28.35 grams
and 1 U.S. gallon = 3.785 liters

RE: A couple of questions.
 

Lessons are usually free at most clubs when you join, and why wouldn't you?!? I have seen club memberships from $35.00 to $50.00 a year so its not unreasonable by any means!!! Its also a safety issue. Clubs don't want a new flyer taking off by himself and being out of control which puts vehicles and other flyers at risk. The clubs offer free training because its better for the new flyer and the club to get the new guy trained properly and safely. There are also usually club events free to the members such as fun flys with free food, contests, prizes ect. that is worth more than the membership fees. In Canada and the US you are also expected to get special insurance for RC flying at RC clubs. In Canada its Called MAAC, in the US its called AMA. Its also not expensive and it could save you a bundle if your plane flys into someones SUV! [8D]

RE: A couple of questions.
 

Heres a link to the Tingalpa club site. http://www.tmac.asn.au/
Lots of links to other Australian clubs and hobby shops etc etc

RE: A couple of questions.
 

dydx,
Here's a couple numbers for you to aid in conversions.

Gallon = 3.79 litres
Ounce = 29.57 cc's (liquid volume)
Ounce = 28.35 grams (Mass or weight), yes this one's confusing for us too. :D
Pound = 0.454 Kilograms

So the typical trainer will weigh in at around 2.5 kilograms and be powered by a 7.54 cc engine. It will carry about 236 to 295 cc of fuel for flights of approximately 10 to 15 minutes.

Here's a picture of a typical Receiver, except that it does not show the antenna, which in the U.S. is typically about 1 meter in length. Receivers, servos, transmitters, servo extensions, etc. can all be purchased individually.

Hitec Rx's can be used with Futaba Tx's (and vice versa), Airtronics and JR are compatible with each other. Servos can be used with any other brand, but some Airtronics would require swapping wires around in the connectors.

Hope this helps. [sm=spinnyeyes.gif]
Dennis-

RE: A couple of questions.
 

Oh, and by the way, the receiver pictured has 7 channels, then there's a "port" for the battery connection that's labelled "B". You would want to install a power switch between the battery pack and the receiver for easier power conservation.

Futaba is set up so that Channel 1 is Ailerons, 2 is Elevator, 3 is Throttle, 4 is Rudder, 5 is usually Flaps, 6 generally Retractable Landing Gear.... Other radio manufacturers have slightly different channel assignments, but generally the four primary functions are the first four channels.
Dennis-

RE: A couple of questions.
 

Ok well thankyou all for your input. It has been very helpful. I went down the Aero Club today to check it out. Spoke with some very enthusiastic ppl. Looks like I will be going back. Thought you might like to check out some of the pics.

[link=http://members.iinet.net.au/~dadawson/Aero/]http://members.iinet.net.au/~dadawson/Aero/[/link]

edit: oops.....hehe....pick the odd one out... ;)

RE: A couple of questions.
 

What? After all that effort doing the conversions and you forgot to change the time to metric?:)

RE: A couple of questions.
 

My bad. I thought his degree was in aeronautical engineering. Yes, for electrical engineering, this would be a dandy project.

RE: A couple of questions.
 

dydx

Looks like you probably got most of the answers you need if you went out to the club.

Think I paid about $25 per hour for lessons, this was to fly the instructors plane with all fuel etc supplied. A lot of clubs have people who will instruct for free, but you need to provide the plane.

Terry