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Old Apr 25, 2002, 11:33 AM
Crashmaster Extraordinair
Clarksville, TN
Joined Apr 2002
730 Posts
A bunch of questions about my Firebird II

First of all, let me say that I *LOVE* my Firebird II. It has definitely gotten me hooked on R/C flying and I feel much less apprehensive about spending $300 on all the equipment for a "real" plane next.

Now, on to my questions...

Are there any chargers available that would be able to charge the batteries for the FB2 (both of them, 4 and 5 cells) without me having to worry about taking them off the charger after the prescribed 2 hours? I have a nasty habit of leaving them on overnight and the instructions say thats a very bad thing. Also, what would happen if I put the 6-cell FBXL battery in my FB2?

What would make a good replacement for the two bars that hold the rubber bands on? One of them has already broken (and been lost in a crash) and right now I am just using two toothpicks with some paper wrapped around the ends.

Ive also had to replace the two small yellow pin/clip doohickeys that stick into the block of foam behind the battery because they tended to pop out of the foam every time I crashed and the prongs on the inside were tearing up the foam something awful. I replaced them with a lego axle with a small pulley on each side. This is working very well because when it crashes the pulleys just get pushed outwards and I can easily re-tighten them, so I guess this one is more of a suggestion than a question.

Is there any good way to keep the propeller from falling off when I crash? Ive now lost 6 props and I am only on my second wing. Seems to me like they picked the wrong part to ship a spare of I am contemplating painting the spinner on the props fluorescent orange but am afraid that it will affect the balance of the prop.

When there are dents, or even small tears, in the wing, what is the best way to fix them? I have been flattening them back out as best as I can and then covering them with scotch tape to preserve the airfoil shape, but this probably isnt an optimal solution. Every time I lose a prop in a ground crash the detaching prop tears a nice gash in the TE of the wing about 3" to the left of the centerline. After a few of those I have what amounts to a 1" radius hole in the wing that I have to cover to preserve the airfoil and its very hard to keep it smooth without something to fill the hole with.

What would cause a single servo (specifically the right ruddervator) to twitch? The enging and left servo work FINE but when I apply no rudder control then the right servo twitches about 1/8th of its range of motion. This causes slightly erratic flight behavior and as a workaround I have put about that much slack in the right control line which eliminates the twitching but also decreases my control range on that rudder. However, the twitching goes away whenever I apply full left or right rudder.

Has anyone ever had a problem with turning authority on the FB2? Mine was very sluggish in turns. I used 1/16" balsa to double the length of the rudders and am getting MUCH better performance out of it now. Is there a better solution? Will I notice any erratic behavior in the long term because of this?
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Old Apr 25, 2002, 12:44 PM
Live to ride... and fly!
Tres Wright's Avatar
Forney, TX
Joined Mar 2002
15,165 Posts
==First of all, let me say that I *LOVE* my Firebird II==

Me too!

==I feel much less apprehensive about spending $300 on all the equipment for a "real" plane next. ==

Make sure you go with a trainer though, it's still a big jump going from the FB2 to a 3 or 4 channel plane. The GWS Tiger Moth would be an excellent next step, you can read lots of cool stuff about the TM by using the search feature. It won't run you 300 either, you'll be in it closer to 200.

On the charger, there are auto shutoff Ni-MH chargers out there, but I just use the wall pack. Like you, I have accidentally left my pack on the charger all night more than once and it appears there was no damage to the pack. It's possible the pack could overheat and vent though. I keep a timer (with buzzer) next to the charger now so I know when charging in complete.

==Also, what would happen if I put the 6-cell FBXL battery in my FB2? ==

I don't notice much of a difference in performance between the 4 and 5 cell packs. The small power gain seems to be offset by the additional weight. The FB will not soar nearly as well with the 5 cell pack. The 6 cell pack would give you an additional small boost in power, but it would also add unwanted weight and possibly burn the motor out if you run it WOT for long.

==What would make a good replacement for the two bars==

Hardwood dowels.

==Is there any good way to keep the propeller from falling off when I crash? Ive now lost 6 props and I am only on my second wing. ==

Dang, you must crash a lot I've got 32 flights on mine, no crashes. It's holding up quite well. Still on the 1st prop and wing. Try a couple of drops of C/A on the prop before pushing it onto the shaft.

==When there are dents, or even small tears, in the wing, what is the best way to fix them?==

Packing tape. You can get yellow tape that is a pretty close match here:

http://www.fast-pack.com/

Unfortunately you have to buy 6 rolls minimum, but if you build a Zagi someday, you'll be glad you have them!

==What would cause a single servo (specifically the right ruddervator) to twitch? The enging and left servo work FINE==

There's only one servo, right and left are both controlled from a servo built into the "motherboard". You could have some damage on the board as a result of all the crashes, you could be getting some interference at your flying area, or it could just be because it's cheap equipment used in the plane. Just get as much mileage as you can from your FB and move onto another plane. It's a good, cheap trainer and a lot of fun, but they had to use substandard equipment to get it to that price range.

==Has anyone ever had a problem with turning authority on the FB2? Mine was very sluggish in turns. I used 1/16" balsa to double the length of the rudders and am getting MUCH better performance out of it now.==

YES. I ended up taking mine apart because it kept getting worse. It's hard to explain, but the servo wheel neutral position changed over many flights, slowly rotating (like I said, cheap equipment). It resulted in the control wires no longer being perpendicular to the throw which greatly reduced the throw amount. I had to untie the lines at the wheel and retie them. Your fix is as good as any.
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Old Apr 25, 2002, 01:37 PM
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Joined Apr 2002
4 Posts
Re: A bunch of questions about my Firebird II

For the charger, you might want to consider one of those Wall Timers. Plug that into the Outlet, plug the Charger into it, and set it to shut off after 2 hours (or whatever you like)

On turning authority, try giving a short burst of power during turns. The extra air flow over the control surfaces will help improve turn authority. I'm not sure if the Firebird II has adjustable control horns, but you might want to try moving the control line to the next holes on the control horn. Some people have increased the size of the control surfaces by grafting an extra piece of styrofoam to them, to make them longer, so y our balsa additions are in the same vein. Shouldn't have an impact on longevity, though it does make you more susceptible to the "death spiral", just make sure you don't maintain input on your turns for too long.

I had some threaded nylon bolts lying around that were just the right size to replace the plastic wing tiedowns. I threaded those through with nuts and washers on the inside and outside of the fuselage (which helps stengthen it too), I was also able to put the end caps from the original bars onto the nylon bolts. Works great with negligable weight increase.
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Last edited by Trojan; Apr 25, 2002 at 01:39 PM.
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Old Apr 25, 2002, 03:02 PM
Crashmaster Extraordinair
Clarksville, TN
Joined Apr 2002
730 Posts
ahh

Tres Wright:

im looking at possibly an indoor plane for my next one. Outdoor flying locations are few and far between around here.

im surprised you didnt notice much of a difference between the battery packs, mine climbs about twice as fast with the 'speed' battery.

toothpick = hardwood dowel

crashing is mostly due to the fact that my flying field is about 500'x200', covered in flowers, and completely surrounded by very tall trees. even a good landing into flower-covered grass is a pretty abrupt stop.

thanks for the packing tape idea, ive got some handy. i dont mind the colors not matching.

how did you take your FB apart? i can see how to unscrew the electronics mount through the bottom and the motor from the sides but it looks like the control lines would prevent you from pulling the assembly out the front of the fuselage.

----

Trojan:

thanks for the wall timer idea! ive got one around here somewhere that I used to use on my lamps.

burst of power in turns does work, but later on in the flight when its taking 80%+ throttle to maintain altitude thats not so great of an option. the FB2 does have adjustable control horns but the stock configuration already uses the highest holes. so far ive only had 'death spiral' problems when i want them, makes for some great "oohs" and "aahs" from the neighbors when the plane goes into a dive and loses about 100' of altitude, but it tends to right itself pretty quick. good idea on the nylon bolts, but I dont have any. ill look for some next time im at a hardware store.
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Old Apr 25, 2002, 04:59 PM
Live to ride... and fly!
Tres Wright's Avatar
Forney, TX
Joined Mar 2002
15,165 Posts
==im looking at possibly an indoor plane for my next one. ==

Like I said, Tiger Moth

==toothpick = hardwood dowel ==

Toothpick=really tiny easily breakable hardwood dowel. I meant something along the lines of 3/8" diameter.

==mine climbs about twice as fast with the 'speed' battery==

Not sure if you mean climb rate or actual speed, but both do slightly improve with the 5 cell. Certainly not by double, that would take a bigger motor! The problem is the glide rate goes down with the extra weight, so more throttle is required to maintain altitude. I get almost identical flight times from the packs in "dead air", better flight times from the 4 cell if there's any thermal activity.

==how did you take your FB apart? i can see how to unscrew the electronics mount through the bottom and the motor from the sides but it looks like the control lines would prevent you from pulling the assembly out the front of the fuselage==

Disconnect the lines at the rear control horns. Remove all the foam blocks including the one in the nose. Remove the 4 screws holding the motherboard, then slide the board forward and out the canopy opening. Be careful not to pull it out too far or the control lines will pull into the boom, then you'll have to install new ones because you can only install them from the outside. I accidentally pulled one through, had to replace it with fishing line.

By the way, the servo wheel problem I mentioned can cause interference problems with internal gears if it gets bad enough. The control lines can actually contact the servo gears and bind, mine was just starting to do it when I took it apart.
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Old Apr 25, 2002, 10:59 PM
Crashmaster Extraordinair
Clarksville, TN
Joined Apr 2002
730 Posts
aha!

didnt know tiger moth was an indoor plane. how fast does it fly (level cruise, no aerobatics)?

a 3/8" dowel would require me to enlarge the holes, they are only about 1/8" diameter to begin with.

i mean climb rate. Ive timed it in dead calm. I can get above the trees surrounding my flying field twice as fast with the 5 cell battery. thats a total climb of maybe 60 feet.

duh, i should have figured that out, theres an easy 9" of play with the back end of the control lines, more than enough to get the whole motherboard out of the fuselage.



PS: canned heat electronics can NOT take the amperage produced by a 4-cell FB2 battery :> ran for about 30 seconds then it cut out and i noticed a very funny smell. now theres a bright brown/orange square burnt into my patch of two-sided tape that was holding the circuit board down.
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Old Apr 26, 2002, 12:21 AM
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kushal_22's Avatar
Kamloops
Joined Dec 2001
6,844 Posts
Tiger moth might fly as fast as your FB. You can slow way down though it is a very stable aircraft. it is very light though and will not handle much wind. If you were wanting a "outdoor" Plane you might want to try a Sky scooter or a Push-E Cat Among many others those two have great durability and can be put back together many many times with some 5 min epoxy.

Mal
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Old Apr 26, 2002, 06:32 AM
HoleDigger
firstdegree's Avatar
Darwin
Joined Oct 2001
151 Posts
sparr

I've got 1 of these:

http://www.balsapr.com/catalog/battN...ductId=S287979

at $40 you can't really go past it - it reverts to trickle after 45 minutes

had to also buy an independent power supply tho
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Old Apr 26, 2002, 09:58 PM
Crashmaster Extraordinair
Clarksville, TN
Joined Apr 2002
730 Posts
so sad

my FB2 is spending tonight outdoors. in a very tall tree. wonder how it will fare, we werent expecting rain but its looking bad as it gets dark. its up in a tree so high/bad that we cant even see it from the ground. gonna have to dig out the climbing gear to get to it tomorrow. wish me luck
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Old Apr 27, 2002, 01:50 PM
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kushal_22's Avatar
Kamloops
Joined Dec 2001
6,844 Posts
Good luck.
I landed my sky scooter on top of a building once and ity did rain! all electrics worked fine(once dried out)In fact all that did not work was my RX and once dry it wporked fine
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