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View Full Version : Why does my TREX keep dropping from the sky?


Riverman
03-25-2007, 02:01 AM
Hi there

I've got a TREX 450SA that flies like a dream 99% of the time, but during the other 1% it likes to shut down and drop from the sky rather abruptly. I can usually regain control after the power comes back on line, but I can see a catastrophy coming if I don't get this glitch figured out. It seems to be a total loss of control, with both the motor and radio gear going off line. I've been trying to truobleshoot the situation for weeks to no avail.

Here's my setup:

TREX 450SA
Align 430L 3550kV motor w/11tooth pinion
Align 35G BL ESC
Hitec Electron 6 rx w/Deans one piece antenna
Hitec Optic 6 w/Spectra tx
Hitec HS-65HB servos all around (x4)
Zoom gyro
Thunder Power 3s 2100mah lipo battery

So far I've tried to address a few things which I thought may be the culpit:
1)I made sure my driveline was nice and drag free so as to not overload the motor/esc. I also lowered my pinion to an 11 tooth thinking I might be drawing too much power resulting in ESC shut down. I've verified my motor and esc are running at an acceptable temperature.
2)I shifted all of the electronics gear around inside my airframe thinking I might be getting internal interference.
3)I swapped the receiver with one from another aircraft.
4) I insulated the antenna and esc wires from the airframe.

None of these efforts helped at all. In fact, lately the problem seems to be getting worse. I love flying this little bird, but the drop outs are going to destroy it prematurely I'm affraid. I think it could likely be intermittent radio interference of some type, but it could also be a faulty ESC/BEC problem. Unfortunately I don't have a spare ESC to swap for troubleshooting. Any suggestions?

Cheers, Brett

Turbojoe
03-25-2007, 02:40 AM
If the motor AND radio both are shutting down I would strongly suspect an electrical connection. Double check your solder joints. You are using Ultra Deans aren't you? If you have a receiver switch I would HIGHLY supect that as the problem. I never trust those switches.


Joe

leapfrog
03-25-2007, 06:50 AM
The symptoms are similar to an ESC shutting down... but you've checked everything related... Hummm...

PilotDane
03-25-2007, 01:03 PM
Is there a pattern to when it is shutting down? Near the end of your battery or when you do a maneuver that pulls a lot of power?

virtual
03-25-2007, 01:54 PM
may it even be a range problem ?

Riverman
03-25-2007, 03:45 PM
My electrical connections seems to be solid. I've played with all of the wires with the machine powered up on the ground with no failures.

I wish they was a pattern to all of this. It will happen during hover a couple feet away from me, and has happened during full throttle fast forward flight a 100 feet out.

I found that I have the Align 35G ESC with the heat sink mounted on top of heatshrink and double sided tape instead of up against the amplifiers like it is supposed to be. I've done the fix and I'll give a try later today. I really don't have much confidence in this issue being the source of my problem as I have had the glitch occur before the esc even has a chance to warm up, but I thought I'd give it a try.

What do you guys think of these ferrite rings some people are using to combat radio interference? Is this just RC mythology?

Riverman
03-25-2007, 05:53 PM
Took the rex out for a flight this morning hoping my Align 35G speed control modification would fix my cutout problem. I hadn't been in the air more than 1 minute and I had already experienced a couple short cut outs. I realized that both occured when the heli was orientated with it's right side facing me. I then deliberately tried to replicate it by going into a right side in hover, and wouldn't you know it, I just about crashed due to the resulting cut out. Did this a couple more times and I've concluded I have a radio reception problem. It occures in a right side in hover because the antenna is mounted on the left side, obviously blocked by the airframe. I had previously suspected this and had lowered the antenna to near the bottom of the skid, but this apparently was not enough.
I had some electrical tape in the car so I removed the antenna from the skid and taped it to the canopy pointed forward with it's full legnth exposed beyond the canopy for the best possible reception. After the mod I flew for the rest of the battey pack (6 min) without a single cut out. I'm now going to experiment with different antenna mount positions to find what works best. I worried I might catch it in the grass if I leave it in it's current "stinger" position.
Not sure about these Dean's antennas. Come to think of it, I've had nothing but problems with all of my machines equiped with them.

Cheers

PilotDane
03-26-2007, 03:39 PM
Time for a Spektrum radio. I've got the DX7 and have never had a radio problem even when flying in a noisy radio environment that drove my old FM radio crazy. The receiver and second receiver pack give you four antennae so you don't have blind spots, and the antennae are so short that they do not protrude beyond the canopy or fuselage.

Turbojoe
03-27-2007, 12:29 AM
Just curious but have you replaced the frame with carbon fiber? I've read about interference issues with the CF frames.

I use an Electron 6 with the Jim's Lightenna and have no problems at all regardless of the heli's orientation. It's going to be interesting to hear what your final solution is. I hope you find it soon.

Joe

shredder777
03-27-2007, 12:44 AM
I use to fly ducted fan jets and I had a similar problem. Comes to find out it was my cell phone.

This may not be your case but, I thought I would throw it out there.

Good luck in finding the gremlin and hanging him by the tail.

Sean

tmyrick1
03-27-2007, 01:14 AM
I used a Dean's antenna on my Trex. I mounted it on the bottom of the frame pointing aft and never had any reception problems.

Riverman
03-28-2007, 06:56 PM
Celphone, heh? Thats very interesting. I always have mine on my person when I fly.

tmyrick1: Good to hear in can be done. I'm not ready to give up the Deans' quite yet.

As for my rex, I've put 4 packs through her and I am so far having the best luck with the antenna mounted on the horizontal stabilizer. I actually had a couple cut outs with it mounted pointing forward off of the nose.
It's not perfect, but I've drastically reduced both the frequency and severity of the cutouts by moving the antenna off of the skids.

Can I just take a moment to point out that the Trex rocks! I'm having a blast with this little bird. I'm improving my forward flight skills and implementing minor aerobatics everytime I fly. I think I'm just about ready to try a roll or a flip. One of these days...

Brutal E
03-28-2007, 10:24 PM
I can not tell you how great it is to have never had to deal with glitches. Makes my purchase of the DX6 and then the DX7 worth every penny. I mount my equipment wherever I want with no problems. Never used other radios as I am new to this hobby but the Spektrum is the first and last radio I ever buy.

Riverman
03-28-2007, 10:36 PM
I hear you.
Thing is, the DX7 is going for well over $300 right now. Couple that with the fact that I have multiple airplanes on the 72MHZ band that I control with my Optic 6 and I would need to purchase several receivers to make the full switch.
In time I most deffinately will make the switch. Right now it's unfortunately not in the budget.

Brutal E
03-28-2007, 10:53 PM
Yeah too bad they do not offer a TX only package. The full size servos and beast of a RX that comes with this package is useless to me. Great if you are doing large scale. I have nothing bigger than a 400 size helicopter.

PilotDane
03-29-2007, 01:32 AM
They are now selling the DX7 transmitter on it's own. I just checked GrandRC's website and they have the transmitter for $230 and the AR7000 receiver for $95.

Brutal E
03-29-2007, 01:42 AM
I prefer the 6000 and 6100 both go for around 60 I think. Nice price on the TX seperate though. Wish they had offered it when I bought mine.

paranoia
03-29-2007, 09:23 PM
the BEC in the ESC cutting out due to over heating...... this BEC can only run at about .6amp at best, and my 450SA uses 1.2 max inflight.

answer use an ext BEC

this one is 19 shipped http://www.dimensionengineering.com/ParkBEC.htm

hope that fixes it.....

Riverman
03-29-2007, 09:53 PM
Paranoia

Thanks for the tip. However, the Align 35G ESC is advertised as having a 2 amp BEC. Where do you get your .6amp figure from? What you suggest about BEC cutout makes a lot of sense to me and I have considered an external BEC before.
I know a lot of people are running TREXs without BECs who have not experienced any problems, and that is why I ultimately never implemented one. I suppose my problem could be a function of my rather large servos, though (Hitec HS-65HBs).

I've ordered products from Dimension Engineering and have been very impressed with the price, product and the shipment times so I think I might give the BEC a try. Plus, it's payday! Why not? Do you think one will be sufficient to power the reciever, 4 servos, and a gyro?

cheers!

Brutal E
03-30-2007, 12:12 AM
I have had no problems like this and when I got overheat problems it was due to a tight tail belt. This set up can run 8 to 10 minutes flat with the heat sync of the ESC being medium warm. I run 13 pinion gear. Not a single stutter. I have those same servos Karbonite version. Plus a high speed 9650 on the tail. Not a hiccup. Maybe check that belt.

paranoia
03-30-2007, 12:40 AM
i think it's samething like 10watts for the BEC only


The amp rating on ESC is for 4.8 to 5volt only!, at 11.1volts the amp output of the BEC is no much more then .6 to .9amps max


fyi i measrued my amp draw using the logger..... I'm using Hs-65 and a 9650 tail servo and a PH35 and a parkbec 5V version.

leapfrog
03-30-2007, 08:01 AM
o.0 Huh?

Sorry paranoia, but I have to "respectively disagree"... the 10W rating is on the "output" stage... after the TO-252 stepdown regulators... the BEC provides 2A peak current (see item 9 of "product features" on page one of the owners manual for the ESC)... I've got several of them (six to be exact - all with HS-65's on cyclic and several options for tail servo and gyro) and I've *never* had a problem with the BEC on any of them. No overheating whatsoever (gotta side with Brutal_E on this one)... and actually, it would more likely be the cutout on the primary side (the motor control) unless there was a stalled servo or servos.

CHELLIE
03-30-2007, 08:36 AM
Interesting problem, I am just wondering if your lipo may be giving out, does this happen with other batteries, a loose cell connection inside the lipo maybe, just a thought, take care, chellie

paranoia
03-30-2007, 06:52 PM
That's cool most people disagree with me about this.....


I don't have a Align 35 ESC manual, However, my PH 35 is rated for 4 micro servos (i don't think a hs65 provides micro torque) only on 3cells or 2 high torque servo's, (the rex uses 4 high torque servos). oh and there's a gyro and rx that needs power too...

What does the Align 35 manual say the max number of servos it can run on 3cells? or doesn't it go into that detail?

Now, the rex will hover and fly w/o the ext bec on a ph35, but it's bec is maxxxed out and runs much hotter then it's should, (and can cutout! when pushed).

I think most people fly w/o a bec and are okay, but most 3d guys i know need the response and power a ext bec can provide.


Note: castle creations esc servo rates are correct, and are clearly defined in there manuals, many other companies don't go into that detail as they don't like to admit the limitations.



(read on below.........)

paranoia
03-30-2007, 07:09 PM
just saw this.....

http://www.hoverhobbies.com/product_info.php?products_id=542&osCsid=f95686aa3fdf85649e17a20c4711e3a7


●BEC output: 5V Max current 2A
2 cells Lithium/6~7 cells Ni-Mh=>4servos
3 cells Lithium/8~9 cells Ni-Mh=>3servos
4 cells Lithium/10~12 cells Ni-Mh=>2servos

oh and this...............


http://www.deeteeenterprises.com/NS.T.Rex.Align.Brushless.35a.ESC.php




align 35 smp esc 6v bec version

BEC output: Max current 2A

2 cells Lithium/6~7 cells Ni-Mh=>4servos

3 cells Lithium/8~9 cells Ni-Mh=>3servos (the rex has 4servos????!!!!)

4 cells Lithium/10~12 cells Ni-Mh=>2servos




so if a 5v battery pack was pluged into the ESC it's BEC could put out up to 2amps and 5v = 10watts this is like a base-line

but at 10v battery pack is pluged in to the esc then the max amps for the bec is 1amp ie 1 / 10 =1amps

and at 12v battery pack it's only .8333 amps on the bec 10/12=.833amps

a fully charged 3cell pack can be at 12.6Volts so 10/12.6 = bec .79amps

on a 4cell 14.4V the amps of the ESC BEC are only .69amps max!

But a high torque servo needs about ~.25amps max (note a HS-55 is about .19amps each) so that's 1amps for 4. so if your pack is putting out +12v your esc bec will start to cook, and when the safty temp circuit will shut down the hole esc! (it's real limited by how fast the ESC can dissipate the heat from the main motor circut and it's bec before it's cooked).



The BEC on a ESC dissipates the extra volts (ie 12v – 5v = 7volts it needs tp get rid of) as heat! most ext BEC doesn't use this method.

so if the voltage of the input goes up, the amps the ESC BEC's can provide goes down, and shouldn't exceed 10watts,

also if the power dips down to low the Rx will loss power and glitch.....






leapfrog;

How, if you fly in sure a way (and or have a setup) that the amp draw for your servo/control system doesn't go above .833 at 12v for too long your good. happy flying to you!





RiverMan;

check all your linkages are moving freely through there full travel make sure the servo’s are not over working, and the swash (not to tight) is freely moving. and the tail pitch lever is free too. make sure the servo's are not being stopped by the linkages just before there full travel if they are trim them at the radio. note most computer radios only run the swash servos at 60% travel

note: if there are linkage problems and you add a ext. bec then you are just going to be over working the servo's!

if you still have this problem replace the esc as it could be damaged.

oh and one parkbec can run 4 high torque servos (or 6 micros), it puts out 1.25amps and 5Volts regadless of input from 6Volts to 33.6volts! The ESC's BEC is 'still on' but it's draw is almost zero leaving the ESC to run the motor. you could connect the esc bec and the parkbec in parallel and then use both, but there's no point leave the ESC to do what it does best





when i'm flying somthing that exceeds the ESC BEC limit (or gets close) i use the packbec, simple as that. i soldered two deans (inline) to the power lines, so i can switch it bewteen planes/helis, just plug it in and go.... for $19 shipped why wouldn't you?

Riverman
03-30-2007, 10:30 PM
Paranoia

Thanks for taking the time to compose that post and research the BEC. I will probably order the BEC tonight. Even if it doesn't solve my problem, the switching regulator is much more efficient and it is certainly cheaper than buying another ESC when I don't even know if mine is at fault.

I'll keep everyone updated with my progress. BTW, I've spent the last three weeks tuning and tweaking my REX to ensure all linkages are free, servos are not bottoming out, and that the belt tension is good. I am very confident that I don't have any rigging issues that are causing my cut outs.

Thanks again to everyone trying to help me out. The response to my call for help has been amazing.


Cheers, Brett

Riverman
04-01-2007, 04:47 PM
I ordered a BEC last night. This is the one I got because the cheaper versions were all sold out:
http://www.dimensionengineering.com/SportBEC.htm

It'll be a couple weeks before it arrives but I'll let you all know how it performs when it shows up.

Cheers

wondersh
04-01-2007, 07:39 PM
What I think is,you should check your params of ESC and make sure the low-battery protection is on mid or high instead of low.And if you could,try other ESCs

leapfrog
04-02-2007, 09:13 AM
Hummm... I've learned something... thanks paranoia!...

I fly mostly circuits and basic aerobatics... 3D only comes into play when there is a necessity for "recovery". Still... with six of them flying, three with GY401's and DS3400G's... one with a GY401 and a 9650, one with a G500T and a 9650, and the "cheapo" version flying a RCE-500X and HS-65... (all with HS-65's on cyclic) one would think I'd have encountered problems... but so far, so good.

My HDX450SE (it has a GY401/DS3400G combo) has over 250 flights... my 450SE (also a GY401/DS3400G combo) has right at 200... My Hoss x4 (it has a 430XL, and GY401/DS3400G combo) has just over 80 flights... my SA#1 (the cheapo) has... uh... well, it had about 180 flights on it... and I'm not sure how many more (I loaned it to a friend to try out), SA#2 (a GY401/9650 - with a funky little frame mount for the tail servo) has about 160 flights, and SA#3 (the G500T/9650 with funky mount also) has about 120 flights... granted, probably 2/3rds of those are indoors (rather calm circuits)... but still...

Oh, well... I'm not going to look a gift horse in the mouth... and I love the idea of a switching reg... (I did the DE-SW033 mod on my DX6 at only 3hrs... but have since moved everything to my DX7)... so I will watch the availability of the ParkBEC... and prolly just upgrade them all to be safe.

arsehoyle
04-05-2007, 09:53 PM
Hey everboda!
New to the forum here, thanks for havin me. Just had to register to share my experience with the same motor cutting issues. I’m gonna take the long wordy way around here so bear with me.
When I first purchased my t-rex it came with a 430L and a 25 amp Align esc. At the time the only experience I had with brushless motors was in 1/16 scale buggies (which are a lot of fun BTW!). I kinda thought, 25 amp esc? My tiny little aon motor uses a 25 amp! But I figured the…pros…that put the combo together surely know what they’re doing, right? Well my first few hovers went fine, not pulling much juice there but, once I built up some skill and confidence, I started having the cutting out issues (cogging is the term used in the 1/16 scale world) and both the motor and esc would get very hot. After several miserable flights and lots of that brittle, plastic landing gear, I decided I would try a 35 amp esc… I dunno from my car experience it just made sense to me. Well the lil rex just came to life! It flew great through numerous charges. However since then (with my growing confidence so goes my shrinking wallet) I installed a complete set of JR digital servos (JRPF300H bout 150 bucks, I like the futaba s9650 tail servo better though) and the carbon fiber frame kit (58 bucks at heliproz, no more linkage slop). Holy shnikeys what a difference! But with the good must come some bad it seems, I started having the same issues again (but, this time for some reason my esc wasn’t getting hot at all). I tried all the obvious things like checking tension in EVERYTHING but if I must say so myself, everything was PERFECT (I’ve been called anal when it comes to building thingsJ). I tried changing the program settings to every combination in the esc, different lipos (brand new ones even), talked to the fellas at the local shop which happens to be heliproz ( www.heliproz.com (http://www.heliproz.com/) with a z not an s (living 10 minutes from those guys is becoming very expensive)) I even searched the net which is how I came across this thread.
Well after loosing much sleep debating whether to buy a new motor, esc, or an external bec, I decided the shiny new servos were just drawing to much power (BTW it does say right on the instruction sheet that comes with the RCE-BL35G “2A- 3cells Li-ion/8-9cells Ni-Mh—3 servos). I opted for the Quark digital 5 amp bec. You do have to disable the on-board bec in your esc but it’s just a matter of pulling the middle (red) pin out of the connector that goes to your rx, I just left mine in tact, folded it back and put a little piece of heat shrink over it.
Ok now for the pertinent information…Riverman you can just skip down to here… for the first pack I was being cautious, almost expecting it not to work, so just hovering a few feet off the ground, and it went just fine. No problems! Halfway through the second pack I got my confidence back and did several stationary rolls, everything went off without a single stutter from the motor! Since then it’s been snowing a little off and on so I’ve just hovered 2 more packs inside the house…no problems. I think you made the right choice buying the bec and you wont be disappointed but please post your results I know other people must be having these same problems and it would be cool if we could affirm this solution. Thanks to all that had the patience to follow along and we’ll be reading ya!
ricci

Riverman
04-07-2007, 05:06 PM
Ok now for the pertinent information…Riverman you can just skip down to here… for the first pack I was being cautious, almost expecting it not to work, so just hovering a few feet off the ground, and it went just fine. No problems! Halfway through the second pack I got my confidence back and did several stationary rolls, everything went off without a single stutter from the motor! Since then it’s been snowing a little off and on so I’ve just hovered 2 more packs inside the house…no problems. I think you made the right choice buying the bec and you wont be disappointed but please post your results I know other people must be having these same problems and it would be cool if we could affirm this solution. Thanks to all that had the patience to follow along and we’ll be reading ya!
ricci

I'll deffinately post my results once the external BEC shows up. And don't let a little snow keep you from flying, Arsehoyle. The TREX can handle it. :D

leapfrog
04-12-2007, 06:12 AM
Hehe... Hey paranoia (rather appropriate nick, seeing as how I'm doing this)... you'll be glad to know that my BECs arrived... but now the problem is getting them all installed into the helis. I'm going to crimp JST connectors to the BECs, and add a JST jumper from the ESC bat connection... and I have to do this for *several* helis... but hopefully, I will see no changes and rather just have a bit more piece of mind.

arsehoyle
04-19-2007, 08:47 PM
Ok some bad news and some good...but first i just wanna say that when it gets reeeeealy cold out, those Align so called "carbon" blades get real brittle. So much that i had one snap off during a sudden pitch change while pulling out of invert. At first I thought one of my neigbors got annoyed and shot it out of the air or the lipo exploded or something. Once one blade goes everything else turns goes hairball instantly.
Now after installing the external bec I had quite a few smooth flights, but the problem soon retuned!!! I robbed my buddy's dx6 from his mx400 and everything worked better than it ever has, except for the fact that the 3 point curves in the radio suck! Well I thought, maybe its just my rx crystal...nope (14 bucks)....crap maybe its my receiver, its just a cheapo single conversion..I'll get a dual conv. R148DF...nope (56 bucks ebay)... maybe my tx crystal???...

me "hey hobby shop guy I need a tx crystal"
hsg "really? why? what's happening?"
me "blah blah blah"
hsg "do you have a carbon fiber or an aluminum frame"
me "uh...yeah..."
hsg "ah... yeah me and my buddy had that same problem w/ our rex's...RF noise amplified by the frame...try these ferrite rings Align makes...(for just this problem, part # k10331ta)...it worked for us!"
me "well...ok...I'll try it, but I really don't think this little $1.99 piece of ceramic is gonna help"
hsg "that'll be $1.99 please."

The preceding was based on a true story
$1.99!!! gdammit! Thats all I needed???...Live n learn. Yay hobby shop guy!

paranoia
04-19-2007, 09:31 PM
leapfrog,

micro deans may be better, i don't like those jst connects. they seem to act like little heaters above 25watts and up....


arsehoyle
just a note: don't use rings with 2.4 gear.... it's only for 72hz stuff

arsehoyle
04-19-2007, 11:10 PM
leapfrog,

micro deans may be better, i don't like those jst connects. they seem to act like little heaters above 25watts and up....


arsehoyle
just a note: don't use rings with 2.4 gear.... it's only for 72hz stuff


rightie-o 72MHz stuff is what I'm using. I just borrowed my pal's spektrum to see if the glitchies would go away...he made me give it back afterwards:mad:

Riverman
04-19-2007, 11:14 PM
Ok some bad news and some good...but first i just wanna say that when it gets reeeeealy cold out, those Align so called "carbon" blades get real brittle. So much that i had one snap off during a sudden pitch change while pulling out of invert. At first I thought one of my neigbors got annoyed and shot it out of the air or the lipo exploded or something. Once one blade goes everything else turns goes hairball instantly.
Now after installing the external bec I had quite a few smooth flights, but the problem soon retuned!!! I robbed my buddy's dx6 from his mx400 and everything worked better than it ever has, except for the fact that the 3 point curves in the radio suck! Well I thought, maybe its just my rx crystal...nope (14 bucks)....crap maybe its my receiver, its just a cheapo single conversion..I'll get a dual conv. R148DF...nope (56 bucks ebay)... maybe my tx crystal???...

me "hey hobby shop guy I need a tx crystal"
hsg "really? why? what's happening?"
me "blah blah blah"
hsg "do you have a carbon fiber or an aluminum frame"
me "uh...yeah..."
hsg "ah... yeah me and my buddy had that same problem w/ our rex's...RF noise amplified by the frame...try these ferrite rings Align makes...(for just this problem, part # k10331ta)...it worked for us!"
me "well...ok...I'll try it, but I really don't think this little $1.99 piece of ceramic is gonna help"
hsg "that'll be $1.99 please."

The preceding was based on a true story
$1.99!!! gdammit! Thats all I needed???...Live n learn. Yay hobby shop guy!

Very interesting indeed. I'll give the ferrite ring a try if this BEC doesn't help my problem.

BTW, I recieved my Dimension Engineering Sport BEC early this week. Due to horrible weather, I have only been able to put one battery pack through it, so it is too early to say if it has cured my dropouts. That one flight was free of dropouts so I'm keeping my fingers crossed...

Dvnts
04-20-2007, 04:38 PM
Hi all, Great thread, I now know why I burned out two align 25 a esc's on my rex 450 hde. I installed a 30 amp esc which is holding out, but after reading this thread I am now considering installing an external bec, or this esc which seems perfect for the rex. Does any body have any experiance with it?
http://www.aircraft-world.com/shopexd.asp?id=4829

paranoia
04-20-2007, 05:04 PM
Hi all, Great thread, I now know why I burned out two align 25 a esc's on my rex 450 hde. I installed a 30 amp esc which is holding out, but after reading this thread I am now considering installing an external bec, or this esc which seems perfect for the rex. Does any body have any experiance with it?
http://www.aircraft-world.com/shopexd.asp?id=4829





dvnts

http://www.aircraft-world.com/prod_datasheets/hp/titan/Titan35-PSW3.pdf

this is the manual, after reading it i would say no, (i'm sure it's a great ESC but it seems to have the same BEC problems as all other ESC). At the top it's bec rating is 5.5V @ 4amps = 22watt? max.

and in the caution section is has a 'big servo disclamer' basicly saying it anything is less then perfect all bets are off.

Riverman
04-27-2007, 11:29 PM
Hey all

Just a follow up to my TRex dropping from the sky problem:

I installed the Dimension Engineering external BEC and I have so far put 4 glitch free battery packs through my 450SA. It's flying great and my confidence in the machine has improved greatly. I've also bumbed my servo voltage up to 6V courtesy of the BEC which is supposed to improve responce, but I don't think I'm yet good enough on the sticks to notice.
Weather permitting I'll really wring this thing out over the coming weeks and I'll post my results. I can say with confidence, though, that my situation has deffinately improved from when I originally started this thread. I'm starting to think that I had both radio reception issues and BEC cutout issues, which really made this situation hard to troubleshoot. In the end the cure may be both a combination of the external BEC and the reposistioning of my whip antenna. Time will tell.

Cheers

wizzard
01-03-2008, 03:53 AM
I have a t-rex and the Mini titan, both using the
CC35 , the old version with only 1 amp bec,
I had 6-8 shutdowns when I first flew the trex
with 450th motor and only a 10c Lipo for power.
After many changes and adjustments, I cured
the shutdowns by minimizing the castle adjustments
on current sensitivity and lipo cutoff settings.
Since then, I have over 200
incident-free flights, still using
the old 1 amp CC 35/bec, with hs55's and the same
10c Lipo. I agree that friction in the system can still
cause overheating leading to the overloading of the motor/esc
combination. However, I can't see a glitch causing any overload or shutdown in the system.
I'm not sure what current limiting programs your align esc has, but that may be your problem.
I have experienced this shutdown in several airplanes
as well, and after minimizing the current limiter and
lipo cutoff sensitivity, this has cured all of my power
cutoff headaches. Good luck on finding your gremlin.
skyhawk