Radio Controlled Planes: May 2008 Archives

More Parkzone Citabria (and Cessna) repairs

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Well, I've made a couple more repairs to the little guy over the past few weeks.

First was the broken shaft (second time). This time I ordered a new motor and 2 props from A Main Hobbies - shipping was only $3.50, and after all was said and done, the package was less then the motor at some stores. Based on some advice from a fellow pilot at a recent fun-fly, I tried just replacing the prop. Turns out, the threaded shaft creates a weak spot right where the threads end. By cutting a bit of styrofoam off the front of the plane to make room for the new prop, and by drilling the hole in the prop slightly bigger, I was able to pressure fit the prop to the stubby shaft and I have flown over an hour on this setup. So, the $15+ motor and an extra prop will remain in their packaging until such time as needed - maybe they might end up in another small bird.

Second was the motor mount. After flying for nearly 30 minutes tonight, I got brave (daring? stupid?) and ended up with a hard nose first landing. This landing would have snapped the previous shaft off at the threads. This time it just knocked the motor loose. It still flew for the rest of the battery (nearly 10 minutes)! Got home and made the following repair:

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The motor had completely freed itself from the previous mounting attempt. Upon inspection, one of the mounting / centering pins was snapped, so CA to the rescue (DON'T GET ANY ON THE STYROFOAM!).

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Once the peg was secured, I turned to the body. The holes were basically clean and intact, so I filled them with a drop of white glue each and pressed the motor back into place.


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The plane is then scotch taped back together and its ready for another evening of fun!

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Enjoy!
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Product Review - Parkzone Citabria

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(Update!: 1 Year review now posted!)

I have owned a Parkzone Citabria for just over a month now, and thought that I could collect my thoughts and opinions on this model to share with the greater community. For those who want the summary first, overall I am thoroughly impressed. It is a decent value, flies great and is reasonably forgiving. Depending on your skill, and location this would make a great first plane.

Type
Electric, brushed motor
High wing
Li-Po battery technology.


Cost
$149 - $159 (unless on sale)

Specifications

  • Type: Indoor Electric (or outdoor on very calm days - it stalls slower then you walk)
  • Wing Span: 16.5 in (420mm)
  • Overall Length: 13.25 in (335mm)
  • Flying Weight: 0.7 oz (20g)
  • Radio: 3-channel 2.4GHz (included)
  • Recommended Battery: 3.7V 70mAh Li-Po battery (included)
  • Battery Life: 8+ minutes at 1/2 throttle
  • Battery Recharge time: 15+ minutes


Handling

With the large dihedral this plane flies nice and slow (compared to the Cessna which has a smaller wing, and therefore moves a lot quicker). In a gym, the plane flies very smoothly at 1/2 throttle. At 1/2 throttle the battery will last nearly 10 minutes.

Outside in a very gentle breeze (the most it can handle) battery life is less then 5 minutes.

Acrobatic handling is minimal due to the wing shape and lack of ailerons, although I have watched an expert pilot fly a big loop and then come out on top inverted and hold that position until he ran out of room (indoor flying).

Dead stick landing - Being a LiPo battery, the controller cuts the engine when the voltage drops too low, saving some power for the receiver and servos. The plane glides smoothly when the power runs out.

Battery life / maintenance

I have 2 batteries that I rotate. Flight times can be as long as 10 minutes, although 6 or 7 is more reasonable. Recharge times are about 15 minutes with fresh AA's, Longer as they AA's run low. Expect to get about 20 recharges out a set of AA's (at least the ones that came with the plane seemed to last about that long).

Again, for the price of the batteries (about $10 each), get 1 or 2 extra. That way you can spend more time flying and less time waiting for a recharge.

Maintenance

Motor oiling. The motor / gear assembly is a bushing. The plane comes with a small amount of fine oil, and it is recommended to add a drop to the gears and bushings before flying. The motor / gear will have a buzz sound as the oil is used up / sprayed out. A fine stiff brush to clean the gears once in a while would be good, as the oil encourages the collection of dust, dirt, etc.

Repairing

Some pilots carry foam safe CA and accelerator, I have not had a need for that. So far, all my repairs have been with scotch tape, and when replacing the motor, plain white glue. CA has also been used to repair the props when blades go flying.

Summary

The plane is very light and relatively simple to fly. The first few flights (especially for beginners) should be done in a very large area since the prop shaft is not very forgiving of a head on with walls or cement floors.

For small entry level planes, I would highly recommend one. They are not a toy, so if you are considering a plane for your 6-10 year old go to Walmart and look at the Palm-Z's for $40.

These are great to keep your flying skills up in the winter, provided you have access to a sufficient indoor space.

Pros

  • Reasonably cheap (for a complete 3 channel airplane system)
  • Good for indoor flying, a school gym is plenty big enough once you get the hang of it.
  • Lots of parts available to handle any repair
  • Decent flight time on a single battery
Cons

  • I have spent almost $200 this year flying this, so it is not the cheapest option available
  • Extremely light - not suitable for outdoors, unless absolutely calm
  • Styrofoam based, so not CA friendly, need expensive foam safe CA
  • Charger requires AA's - does not have AC adapter option.


Tips for new R/C pilots

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Funding / Budget

Before starting, figure out what you can afford. Here is a list of things to plan to pay for in the first year:

  • Insurance. In Canada it is MAAC, and it will cost $75 per year. No club will (or should) let you fly in their field / location without it.
  • Club membership. Most of the larger clubs in Winnipeg have an initial / new membership fee in addition to the regular annual dues. In Winnipeg the dues are about $50-60 / year, plus new member fees. Plan at least $100 for the first year.
  • Plane and radio - depending on what your goal is, plan to spend at least $150 for a very small, basic plane. Gas trainers won't be airborne until you have spent closer to $500 for everything you need (see below for more details)
  • Maintenance - this will depend on:
    • Gas - Nitro fuel is not cheap. The bigger the bird, the more thirsty it is.
    • Electric - To make the most of an evening, you will need enough batteries to get 3 or 4 flights at 10-15 minutes each. So, depending on how you pay for a good quick charger, you should have at least 2 sets of batteries.
    • Self taught vs Over the shoulder training vs Formal training - the more you try and teach yourself, the more you will crash in the beginning. This can be very frustrating as crashing 5 minutes into a flight means it may be days before you get to try another 5 minute flight. Not a good way to gain experience. If you are flying anything gas or fast, get help before you power up!
  • Miscelaneous
    • Getting to the field, the one club I belong to is 1/2 hour drive away. This is an issue both in gas for the car, and also flying time. Travel there and back is an hour, add 1/2 to setup and tear down, and you may not have much time left to fly in the evening after supper.
    • Raffles, fund raisers, meals at the fields, etc.
  • By way of example, I have spent just over $300 on planes and have 2 working planes to show for it (ok, the Citabria is grounded waiting for parts). I have spent $75 on MAAC insurance this year and $120 on club membership fees. Almost $500 to get airborne - this is very cheap. It would be trivial to double that for the first year. I have also bought some bits here and there to support the various clubs. Next year, my costs should go down (unless I decide to upgrade a plane or two...). I expect that next year my costs will be $75 MAAC and $70-100 on memberships and maybe another $100 on parts for the planes (I would like another 1500mAh battery) for a total of $375.

Radio

Get a good radio! A good investment in a radio can save a lot of grief later on. My first radio was a simple 3 channel FM unit with mechanical trim, no trainer link, no programming, no dual rate. It was sink or swim (crash or fly) with this baby.

2.4Ghz vs 72 MHz - The 'old' radios (like mine) use crystal controlled channels, and only one pilot can use a channel at a time. This can cause conflicts and down time if too many pilots at your field / club use the same channel. It can also cause a quite burrial of your plane if you are flying in a park and someone else nearby fires up their transmitter. If possible, and if starting from scratch I would recommend avoiding the 72MHz radios with one exception. The newer 2.4Ghz radios are slick. I'm sure there is a limit somewhere, but I have seen nearly 10 planes in the air at once all using 2.4GHz. No channel fussing, just turn on and go (once the Tx and Rx are synced). The main drawback is some of the new first person video gear that people are adding to their R/C's use 2.4GHz to transmit the video, and this will cause interference. So if FPV is in your plans, look to some other frequency.

Training link - this lets you connect your radio to a more experienced pilots radio. Give the pro the master radio, and you use the slave. He gets the plane up, trimmed and stable. A flick of a switch and now you are flying - if you run into trouble, a quick flick of a switch and he's in control recovering the plane and saving you a lot of money and time.

Dual Rate - for beginners, this is gold! (Even pro's make use of this). Essentially the Dual Rate switch reduces the sensitivty of the controls making it easier for fat slow fingered beginners to keep the plane under control. Even slow planes are surprisingly responsive to beginners, and the result is often over controlling the plane, pilot induced oscillations and crashes. Experienced pilots will use the dual rate to warm up their fingers before getting serious with controls. On my sailplane I have the elevator and rudder both set to 75% on the down setting and 100% on the up. I have yet to return to the up / full responsiveness setting.

Mixing throttle / rudder or aileron - just started playing with this. Get some help with this feature. With my sailplane, full throttle causes a noticable yaw (turn) to the right. By programming a 10% mix between the throttle and rudder, as I throttle up, the radio automatically mixes in just the right amount of left rudder to keep things straight. Now I can focus on the basics and not be confused by the extras.

Plane

For your first plane, here are some things to consider before putting your money down.

Trainer / slow flyer / acrobatic

By all means, stay away from the fancy high performance acrobatic wonder birds. At least for now. The more fancy the planes acrobatic capabilities are, the more inherently unstable the plane has to be. In other words, acrobatic airplanes are designed to crash unless you can convince them otherwise.

Slow flyers - gliders

These offer some benefits of being easy to fly and therefore learn. They are also much easier to maintain, and in some cases easier to repair. They are mostly electric, and are quite light which has 2 main draw backs. The light weight limits the flying conditions to very calm weather or even indoor and the electric may also put you out from some of the larger clubs who enjoy larger gas powered planes.

Gliders are only good if you have a good high start or an electric pod. I'd strongly recommend investing in a power pod. Off a high start, you'll only be getting a few minutes of flight before you have to land (have you figured out how to fly in 2 minutes? much less land?). Until you get better at slow turns and can soar, the high-starts / slope launches are not recommended.

Maintenance / ease of repair

Here, larger maybe better. The really small planes need neurosurgery like skills to fix, and adding glue and reinforcement can quickly affect the CG. Some of the foam based planes are ok to glue with CA, but make sure before trying. CA will disolve certain styrofoam, leaving you more damaged then before.

Balancing - CG

Make sure your plane is balanced properly! And make sure anything inside is secured. Moving the center of gravity too far back will decrease the stability and increase the chance of a stall. Too far forward and the plane will have to fly too fast, possibly faster then you can keep up with - it might not even be able to get off the ground.

Always recheck your balance after any hard landing (better yet, it only takes a few seconds, check it before every flight - not just at the start of the day).

Dihedral

This is part of the plane style. If you look at a glider, slow flyer or trainer from the front, you should notice that the main wing forms a shallow V shape with the plane at the center. This is a good thing. This wing shape will cause a balanced plane to automatically level and straighten out if the controls are released. This inherent stability helps to dampen out and reduce the affects of over controlling by the pilot.

Asymmetric air foil

Looking at the main wing from the side, the shape should be a lopsided rain drop. With the top fatter then the bottom (the bottom might even be completely flat). This results in a wing with lots of lift, which means the plane doesn't have to fly as fast to get air borne. A slower plane requires less attention to keep airborne, and is more forgiving to new students.

Acrobatic planes have no dihedral and a symmetric airfoil. They roll real fast - which is good if you know what you are doing, bad if you don't.

Large wing / slow plane

Simply put, 2 planes side by side, the one with the larger wing will fly slower and be easier to learn on. The Parkzone Citabria flies slower and is more gentle then its Cessna sibling.

Electric vs gas

Electric planes have come a long way. It used to be that gas could out fly an electric and was therefore better to learn on. A longer flight meant more time to figure out the controls and practise turns, level flight, etc. before landing. Modern electric planes, especially some of the slower ones can easily provide 10+ minutes of flight which is comparable to most gas planes. The trade off is the initial cost. Buying enough batteries to be able to get 3 or 4 flights an evening might cost more then the plane.

Electric planes are lighter and need calmer wind, but often clubs have extended hours for electrics because they are quieter.

Indoor vs outdoor

In the cold winter months, it would be nice to maintain the skills you have learned. So get a small electric plane and join an indoor flying club. Learning indoors will be more challenging, so maybe wait until you have some experience first. Flying a little outside the 'box' when outside because you didn't put enough rudder into the turn will get you some dirty looks and maybe a warning. Do that inside a concrete gymnasium and you maybe going home with more pieces then you arrived.

Club / Training

Find a club that is compatible with the type of plane you choose. The club I initially joined, while well organized and comprised of many friendly members is geared to larger gas/nitro powered planes. Starting out with my electric powered sailplane has not been received as well as I would have liked. The electric indoor club I joined later in the year was very warm and receptive to me with my Parkzone Citabria. So, next year I will be reviewing my club memberships to make sure they better align with the type of planes I own and fly.

Training - having an experienced pilot beside you those first few flights is very helpful. It can be done without the help, but if my experience is normal (and I suspect it is) it won't be cheap. Landing is hard, and planes are expensive enough without having to repair them constantly.

Comments

If you have any more tips or comments, please leave them. I'd love to hear from you and I'd like to be useful (correct) in the advice I am giving.