sxates

Critter,

Before I got to your comment on page 2, I was already thinking "why not just mount little servos on the tail?"

I think when I get around to doing this myself, I may actually try that. I don't think it would add too much weight down there--probably not any more than the full length control rods anyway. Does anybody see any obvious flaws with that plan?

critterhunter

Probably the only drawback would be distracting from the looks and a little wind flow disruption. The main concern would be throwing the COG off to make things a bit tail heavy. Tail heavy planes are almost impossible to fly. While on that topic, anybody know what the COG spot is on this plane? I think there is a standard formula for "wing and tail" designs like this...something like 1/3rds or 2/3rds back from the leading edge of the wing? I have yet to try flying the completed plane. Mainly because I've got to fix a crease at the tip of the wing where the carbon rod I installed ends. I'd also like to check for proper COG before flying. I've been using the time to convert the Challenger over to a brushless motor, lipos, control rods, and standard electronics. See another thread called something like "Converting A Challenger Or Extreme Over To Standard Electronics" or something similar. I'll be posting more pictures in that thread as I'm making good progress. Actually, after doing the Extreme conversion the Challenger one is going nice and easy as both are very similar.

By the way, has anybody weighed the stock Extreme with a 6 or 7 cell pack (specify) to see it's ready to fly weight. I suspect the stock ready to fly weight listed for the bird is not correct. I've recently weighed my converted bird and need a reference point to compare.

critterhunter

And here's the other thread you might find helpful...

sxates

BTW, I believe COG for the ABX is right where the xport accessories clip on --about the back edge of the wing.

critterhunter

Makes total sense as you'd want the modules at the COG spot. Never thought of something so simple.

TMIB

I've been watching this thread for a while now with some excitement. I'm also trying to convert an Aerobird Extreme over to standard electronics.

Like a previous poster, I also have HS-81 servos and a Castle Creations Pegasus 35 ESC. I also have a Hitec Micro 555 receiver. I've got a half-dozen or so stock motors, so I'll be messing around with reverse timing and running one in. (seating the brushes)

My question is in regards to batteries. I'd really like to go with li-poly batteries on this plane, both for the power and for the duration of flight.

I have a li-poly from another plane, it's a Thunder Power 1320 mAH/7.4 V battery. Rated at 10-12c cont/16c burst, 13A-15A/22A.

By itself that's probably not enough. The stock battery for the aero is like 1700 mAH or so and the nicer stock one is 3000 mAh.

My question:

What do you recommend I do for a li-poly battery setup? Should I get a second one similar to what I have already and wire them in parallel, or am I better off with getting a whole new battery setup? Any specific recommendations based on the setup I'll be using?

Thanks in advance!

--TMIB

sxates

If you went ahead and got a brushless motor your existing battery would likely be adequate. I don't know about running lipo's in parallel, but it would make me a little nervous to do it.

TMIB

I don't know- I'm hesitating to switch to a brushless motor in this plane. Not because I don't recognize the benefits of it, but because I have a ton of stock motors for it just taking up shelf space.

I'd rather buy another lipo, knowing that I can use it in several other planes later on if need be, and stick with the stock motor.

Of course, the best performance would likely come from a brushless motor AND a new battery setup.

I don't know much about wiring up lipos in parallel either, or for that matter how best to determine the needs in terms of battery size and amps.

critterhunter

Lipos in parallel will double the capacity (run time) and double the C raiting (ability to deliver amps). So, with two of those packs in parallel it'll give you 26 to 30 amps constant amp draw ability Right off the top of my head I can't remember what the Extreme 540 motor is drawing amp wise with the stock prop (check the start of this thread...it's in there somewhere), but I believe it's in the 20s somewhere. Should be good enough or, if you had to, you could limit your full throttle to a few seconds at a time if the numbers are close. You'll have roughly over 2600ma of capacity which will make for some good flight time. My 3300MA nimh packs give me gobs of it. Of course you'll want to use a speed control that is 2 cell lipo cutoff compatible. Also, your two cell pack is 7.4 volts which is fine for the 540. The 540 will run on 6 cell (7.2v) or 7 cell (8.4v) nimh packs with no problem. Bet it can even handle being pushed to 11 volts on a 3 cell lipo. You'll probably be at roughly half the weight of on of my 3300ma nimh packs so you might need to add some weight to the nose to get COG near where it should be (if it isn't close anyway...bet it won't need any weight added). To wire two lipo packs in parallel you won't need to do any soldering. Just pick up the proper wire harness that will plug the two packs into each other and then into the plane. I'd rather wire to packs in parallel instead of buying one pack that can handle the amp draw and have 2000-3000ma of capacity (expensive). You're right, then you can use those two packs for other birds as well. Refer to the E-Flite power forum under a thread called "wiring lipos in parallel" or something similar.

PS-May be finaly taking up the converted Extreme this Sunday! It's been a LONG winter but the weather is getting better in Cleveland and I have the plane ready to try.

TMIB

Thanks for the excellent info!

I admit my ignorance on this subject. How can I tell? I have the Castle Creations Pegasus 35. The documentation for it says:

Six to eight cells with three standard micro servos
six to eight cells with two high-torque micro servos
Up to 10 cells with two standard micro servos
Eighteen cells MAX with BEC disabled.

it later says:

Cutoff- The motor cutoff will occur when the input battery voltage drops below 4.7V for more than one half second.

Thanks!
--TMIB

critterhunter

Just thought I'd update you guys on my install of the standard electronics. I just recently tried taking the Extreme out again and only got it to fly in high winds for a few minutes. Ended up with a hard sloppy landing and once again stripped a servo in it. That was the final straw. I put all that work into it over the winter getting the control rods to work and ended up stripping a servo again on this first spring flight attempt. I'm not saying control rods won't work. They will. I just did a bad job of routing them to prevent binding and perhaps picked the wrong rods for it.

Anyway, the electronics install was fine, solid, and I knew it would work fine. So, I took the bird home and removed the rods (and the wood I was using at the end of the control board to secure the sleeves). The rest of the board is exactly the same as per the photos. Balsa or ply would probably be a better choice but (as the photos show) I used thin aluminum to mount everything. Pretty light anyway.

As an overview, the previous photos show me using HS81 servos mounted in the original configuration the stock board used. I have a 6 channel JR RX (600?) ziptied to the upper left of the board on the side of that servo. The speed control is a 50 amp Electrifly (Electraflight? Whatever...) brushed speed control. This is overkill as the motor draws in the twenty some amp range but should keep things cool. It's mounted at the upper right of the board using zipties and has it's heat sink flush with the aluminum circuit board to keep it cooler. I'm running 3300ma 6 and 7 cell packs in it that I made.

So, as I've said, I didn't get much use of my homemade packs last summer as the stock electronics that come with the Extreme kept bombing out. Fets, broken traces, and other problems I couldn't even track down had me buying two or three stock bird bodies until I finally went to standard electronics. Then the control rod issue has kept the plane grounded pretty much since the fall of last year. Bottom line is I had enough. Control rods are not very easy to get to work with a boom and rod type plane like this. It can be done, but it aint easy. I yoked out the rods and wood sleeve mount and went back to fishing line. I even went back to the stock tail horns on my homemade coruplast tail for now because I just wanted this thing to fly. And it did today...GREAT!

No problems from the start. Just needed a some downward elevator to trim it out as it wanted to climb too much. I think this is probably due to the fact that the plane is probably a bit lighter than it was with the stock gear. Have to check the COG to be sure. Anyway, two great long flights, a few loops, and no problems. Happy to finaly have this bird back in the air. The 50 amp speed control was cool after a wide open throttle flight. The 3300ma packs were also cool after being ran completely down to exercise them after a long winter's sleep. They can handle the amp draw much more better than the stock packs. The stock 540 motor in the plane also has much more power thanks to a quality speed control in the plane rather than the stock one with it's weak FET. Very happy to have such good results and feel much more confident that the plane won't fail on me in the air like I did with the stock electronics. My only concern at the moment is the stock horns. They are flimsy and do tend to fail. I only wanted to use them as a temporary thing to eliminate any other potential problems while I figured this thing out. I'll be going back to du-bro horns soon enough.

critterhunter

By the way, has anybody figured out what size prop the stock 540 is using? This motor has just enough extra spunk now that I can hear the prop flexing a bit under extreme loads while doing stunts. It's a rather flimsy prop and I'm much rather replace it with a good APC or some other brand and a good bullet mount on the shaft.

(You can also find related information on installing standard electronics in an Extreme in a thread called "Installing Standard Electronics In A Challenger Or Extreme", or something similar)

khalsans

My Feedback: (7)

I can believe that the ESC runs a lot cooler- I just did a tear-down on one of those big ESCs, and they put a lot of surface-mount FETS in parallel on the circuit board for really low resistance and inductance compared to the stock Aerobird single FET. Then they put a sheet of aluminum over the whole lot for a heat sink. Lots of surface area for dissipating heat.

How do you make 3300ma 6 and 7 cell packs? Are these Lipo or NiMh?

critterhunter

They are nimh packs. Think they are Powerizers or a name similar. So far very happy with them and the flights are very long with plenty of power. The Extreme is the only plane I'm still using nimhs in. Everything else is lipos now.

TMIB

Ok, I'm really close to just dumping this whole thing in the trash.

As mentioned above I'm using HS-81 servos and a Castle Creations Pegasus 35 ESC. I also have a Hitec Micro 555 receiver.

I tried all sorts of combinations of control rod routing with no luck. No matter what I do to try and route them, they are putting strain on the servos and done move smoothly. I tried going back to the stock fishing line/rubber band solution, only that works like crap too. It never moves the same amount from one activation to the next. That is, I can move the stick back and forth and the tail flaps will move a different amount after a while, since the rubber band is not a precise method of pulling.

To make matters worse, I can't seem to get the v-tail mixing on my laser 4 to work properly. It mixes just fine (channels 2 and 4), but it mixes them the wrong way. That is, when I move the rudder, the flaps move in unison. When I move the elevator, they are reversed from one another. It should be the other way around. I tried switching the channels the servos are plugged into, reversing them on the radio, etc. No luck.

So what I have at this point is a bunch of parts. I think I just need to buy a slowstick, keep my flight pack parts and dump all my Aerobird stuff in the trash.

critterhunter

I had the same headaches with control rods and went back to fishing line. Control rods CAN be made to work on a pod and boom craft such as this, but I simply was sick of playing with it and wanted to fly the thing. I got a few good weeks of flight out of mine finally, but the Extreme curse seems to live on...I was sailing around high with the motor off when some low clouds moved in that I didn't notice until it was too late. Plane drifted into the clouds and I instantly pushed forward and to the right, hoping to see it spiral down out of them, but it never appeared again. I had five other people watching for the plane as I held the controls that way for a good ten minutes. I was flying in a large field in the middle of my friend's massive property so, even though the plane was way up there, I am pretty confident it must have landed somewhere on his property in the woods or fields. I'm going to strap a camera to my Stryker and see if I can spot a glint of yellow from the air. There are also two Challengers and a Scout lost out there that I'll be looking for that friends lost.

So, at the moment I've lost two HS81s, a 50 amp Electrify speed control, a 540 brushed motor, and a 6 cell 3300ma nimh pack. The plane body doesn't bother me as much because it was beat up they are cheap enough. Well, the wing was new and I cringe at that being gone.

I'd go back to fishing line and the stock horns for now. Aftermarket horns are better (less chance of breaking), but it can be tricky to hitch the rubberband up to them for consistant movement. You must also make sure that you are mounting the horns in the proper place. Easy enough for a stock tail but I was using a coruplast one and had to match the horn placement on my homemade one. If the rubberband isn't the perfect strength and length you'll also have problems. I used the stock rubberband.

The other thing to watch out for is being tail heavy. The control rods will cause this. However, if with using fishing line the plane was a bit tail heavy when using my 6 cell versus the 7. I believe the fact that the electronics I installed are probably a bit lighter than the stock junk caused this problem. If the plane seems to want to stand up on it's tail under full power, or acts like it is dragging something behind it, you can bet the center of gravity is off. I'm no expert, but I believe the formula for figuring out the proper COG is 30% back from the leading edge of the wing. Better to be a bit nose heavy but never tail heavy.

As for the tail mixing. I think I'm not using V-Tail on my radio. I'm only going by memory at the moment but I think my servos are plugged into the rudder and elevator or rudder and aileron. And, I think I'm using delta, flapperon, or something other than V-Tail. The only way to find out is keep playing with the radio settings and the servos.

austin1977

Hi i am about to convert my aerobird extreme to standard radios and convert tail to depron,so i wont bend. i will be using 2 mirco servos and speed controller and the usual other bits needed. i have done it b4 on a ABC and it worked well.
I will post pics and info to show how its done. when i did it on the ABC i used the side of a nail gun box to hold the servos and other parts.
I am making a start on it 2nite and hope to do it within a week or so. i have made a basic picture of what it will look like on my computer. So please comment if u think u would like pics or any info about wot im gettin my self into lol.
[img][/img]

Vdisoriented

Sounds good, Thanks to all who posted on this thread, cause I just cracked the board in my extreme and standard elctronics are going in it. I never liked stock anyway, even though stock has not given me problems on my challenger, but I might switch that one two just so I would only have to cary around one radio. I will try to post my mods too, in case anyone wants to try them. Thanks again.

critterhunter

I'll be posting photos sooner or later as well when I get around to building another Extreme with standard electronics. The body ($20 without electronics), wing ($20), and tail (free if you make one out of coruplast) are all it takes to build this plane so it's a great buy and the parts are stocked on most hobby store shelves.

Fly Rat

Has anyone Put a standard tail on the extreme ? I am in the process of installing standard electronics and I wanted to use a standard tail as the ground handling is one of the things I most disliked about this Bird.