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rocket_jim
11-07-2005, 12:08 AM
I have 2 Firebird Commander IIs that have seen better days. Wondering if there is any practical reuse for the 2-channel airborne electronics. Yes I already wish for 3-channel anyway for wind penetration.

The foam wing and the V-tail and the carbon fibre tail boom all seem reasonable, but the plastic fuselage and the wing attachment and the hatch/battery installation and the motor location seem that they could use improvement.

For example, the motor tends to slide around on top the narrow slippery plastic fuselage and then the prop cuts way into the $15 wing on a cartwheel landing. If the motor were located about an inch further back, much less wing damage would occur. And the plane would probably be quieter too. The rubber-band-closed hatch is really marginal in terms of access and plugging/unplugging, unless you have tiny fingers, and the battery tends to fly out on landing, jerking on the wires, trying to dislodge the electronics board. The little foam pieces in front of and rear of the battery tend to get knocked out of place (held in with double-faced tape), letting the battery move around in flight, affecting the CG.

I'm thinking of more of a flat plate or foam fuselage where the motor, electronics, battery, etc. could be side-mounted instead of buried inside an inaccessable fuselage. Also thinking of push rods instead of those silly fishing line controls.

Suggestions?
Thanks, Jim

Elfwreck
11-07-2005, 08:06 AM
Hey now,
From the rude to hopefuly helpful.
Best suggestion; dump it all and get a real trainer and radio, say an Estarter and Hitec optic 6 radio. Rude? Yes, but the best solution really.

O.k. to answer you specific questions:
The avionics aren't compatable with any other systems, so they're not worth saving, still you could use them till something breaks.
Also this thing is rudder/throttle isn't it? So you'd have to stick with that.
Before you build something nifty check the decolage, that's the angle of the wing in relationship to the stab. Do the same with the motor thrust angle on a model like this they are vital!
Go ahead and use the "carbon" boom if it's strong enough (can you flex it easily? No? Good.) you can use layered meat tray foam for the profile fuse.Use foam safe Ca to glue it together. You can use the same meat tray foam for the tail bits and use tape for the control surface hinges.
A drop of foam safe Ca will glue the servos to the foam fuse and you can attatch the battery with velcro. Make sure you put the balance point in the same place and it should er, fly, as it did before, maybe better if you keep the weight down.
Oh yeah, for the motor mount; you could layer meat tray foam together for this too. Cut a Kabob skewer in half, and lay both pieces on a one inch square of foam then glue another piece the same size on top of that to make a sandwitch. Then add a couple of narrow pieces along the sides to help hold the motor in place, glue it to the correct spot on the fuse and wrap a rubber band from one skewer end around the motor to anoither skewer end. It'll hold just fine I've used it for years on a Wing-O and it's never failed me yet.
I hope this all makes some sense to you, I know it's a lot to swallow at once. Good luck and start saving for that Estarter...
RobII

Matt Kirsch
11-07-2005, 05:08 PM
You can certainly re-use the electronics with a little creativity, which means building your own plane. There's really not much beyond the Firebird series that uses this kind of control.

One thing to keep in mind is that these planes are resilient, but not crashproof. The way you describe your experiences in the "landing" thread, the kind of damage you're describing is to be expected. You can only smash the plane into the ground so many times before something breaks, if you know what I mean...

Most any damage can be repaired with a little creativity. Check out some of the threads on this site, RCGroups, and RCUniverse on repairs and mods made to the Firebirds.

VACaver
11-07-2005, 10:39 PM
If you REALLY need to cut down on costs, your electronics can be re-used in other airplanes.

Here's a link on where you can buy a receiver: http://hobbypeople.net/gallery/443565.asp

rocket_jim
11-09-2005, 01:01 PM
VACaver, are you saying that the receiver you linked to will work with the transmitters I already have?

I've been assuming that these transmitters were somehow "special" and would work only with the special receiver on board my Firebird Commander II. Or is this transmitter just a plain ordinary 27 Mhz AM unit, and all the smarts for the different modes, the motor-lock-out, the speical plug-in modules, etc. built into the receiver?

Thanks,
Jim

Timm
11-09-2005, 06:45 PM
Jim, It sounds like you have not stuffed on the 'normal' modifications to your Commander. With the mods shown in this thread:

http://www.wattflyer.com/forums/showthread.php?t=274

you will get much better durability and you will survive just about any crash. The thread talks about the Challenger but the mods are exactly the same on the Commander. After a few crashes the Commanders Centre Of Gravity moves forward as the polystyrene gets compressed in front of the battery. Make sure you use something (like some folded cardboard) to push the battery back so that the COG is corrected.

If you are using the 7-cell pack this affects the COG as well. Some Commander pilots cut a slice of polystyrene from behind the battery (about 1/4" - 1/2") and move it in front of the battery when using the 7-cell pack, this corrects the COG. With the COG correct the Commander lands pretty well, but unless you are landing on a very smooth surface then leave off the landing gear as this only tips the plane over.

The Commander is also a V-tail mixer and uses Elevons instead of a Rudder to steer, these only lift upwards (unlike the Challenger which has one move up while the other moves down), this can be used to Flare the plane as it comes in to land by giving a bit of left-right stick just above the ground, quickly enough so that the plane does not get a chance to change direction.

VACaver
11-10-2005, 12:43 AM
Rocket,

That link is for a 27Mhz receiver. You'll still need to supply a speed controller and servos, but at least you'll still be able to use your transmitter.

In truth, though, you're better off buying a new radio outfit...it will give you more versatility.

rocket_jim
11-10-2005, 12:23 PM
Timm - thanks for the link. I've spent some time there and in other similar threads. It's a little hard to immediately know which things are applicable to different planes. I understand now that there are several different but similar plastic fuselage planes: Scout, Commander, Challenger, T-bird and so forth. And nearly all the wings are foam now, so mostly a wing seems like a wing. So I'm now able to garner some stuff from various threads. But there is so much chit chat to wade thru. And I'm guilty of that too.

You said, " you will get much better durability and you will survive just about any crash." Now that so far I cannot see. Seems so far like most any crash at high speed at any significant angle from the horizontal into something hard like the ground (especially here after several months with no rain!), despite theoretically soft weeds overhead, will shove every thing hard. My lawn dart-like crash due to a sudden gust of wind shoved everything forward so hard and so far that the little styrofoam blocks in front of and behind the battery were smashed out of place; the battery opened the hatch and flew out, jerking the wire; the receiver was dislodged and is now loose inside the fuselage; the wing front crumpled and still jumped over the front lip in the fuselage; the prop somehow chewed up the wing trailing edge; the hinged tail surfaces were ripped off the foam core; and the carbon fibre tail boom broke back at the tail. But the wing did not break, go figure! Just a sudden gust of wind and a LOT of damage resulted. And I backed off the throttle early, but to no avail. MY LHS told me that power-on crashes cause the most damage. To just let go of everything if a crash seems imminent. So I did.

But I do have that plane put back together (shorter, heavier, and much uglier) and flying to a small degree. Still working to get the CG right and the tail adjusted properly. But nothing like new. It would have taken $100 for a brand new one to accomplish that. But there is something to be said about being able to get back in the air in minutes literally brand new for $100 (or I saw it mail order for $85, so perhaps the Commander II price may be coming down!). And to have another flight battery and more transmitter batteries in the process. But how many chargers and unique transmitters do you need? Wish just the plane itself and no transmitter, flying CD, or other accessories was available for these RTFs. But I suppose that would be $90 instead of the $100 for everything.

Another thing I wonder about is the effect of adding all the heavy packing tape and tie wraps and motor mount doublers and epoxy and such. Everything added affects the aerodynamics at least some and makes the plane heavier and thereby has to reduce the inherent performance, making just staying in the air more difficult, and adding more mass to the unavoidable crashes. I'd like to see some ways to make it lighter and still stronger and more crash-resistant. Since crashes are "when?" not "if?"

Jim Marconnet

Timm
11-10-2005, 04:28 PM
Jim, it sounds as though the lack of mods caused the problem. What appears to have happened is that the battery was ejected on landing, this pulled the receiver / ESC from the fuselage and this pulled the 'V' tail control lines. That, in turn, ripped the elevons from the tail and broke the tail boom. It is possible that the receiver / ESC was helped on the way by the motor giving it a good clout.

If the canopy was locked shut (as per the mods on another thread), and the motor was tie-wrapped in place then it is possible that the crash would have dislodged the main wing (which is quite acceptable, it's held on with elastic bands) and the prop may have taken a bite out of it. Compare that sort of damage to the damage that would be done to a balsa kit and you can see that these RTF's are very resilient. The plan is that the mods stop things moving in the first place, it is the momentum that causes the problems.

Both the Challenger and Commander are very robust and mine have survived all crashes without resorting to a new fuse, and I crash quite often:

http://www.meeknet.co.uk/crashes_2.wmv

http://www.meeknet.co.uk/crashes_3.wmv

The Challenger is still going strong and the Commander was lost in the normal way.

P.S. I'm not sure if the Commander II has the same electronics as the Commander I, but to set up a 'cruise' mode switch OFF the transmitter, remove the battery from the plane, refit the battery (after 10 seconds), set the throttle trim FULLY BACK and then switch the transmitter ON. The plane learns the current trim setting as the centre position, so when you move the trim forwards you should find that the motor will run at a speed sufficient to keep altitude.

rocket_jim
11-11-2005, 02:03 AM
Timm, thanks for the hypothesis, but I doubt that mods or the lack thereof made much difference in this particular worst case. The plane just hit the ground real fast and real hard and lots of stuff broke!

Jim

Hemicyon
11-16-2005, 03:41 AM
I have an old Commander sitting around and its still flying but now that I have a few more planes I've lost interest in 2 channels.

I think I'm going to get some foam and see if I can't use the guts and radio to make myself an airboat/sled (its going to be winter soon) out of it. Should be easy enough...

stevecooper
09-18-2006, 01:29 AM
Jim: you can take it as is and make yourself an airboat, I'm do'in one up now with one of the nab'er'hood kid's from our club MULLET MAURODERS, think about it, pusher motor, ESC, reciever, pull-pull (for rudder)servo! let's go to the lake!!!!!(or to the snowbank with my bub Hemicyon) your bub, steve