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Old Mar 08, 2005, 10:35 PM
Dert Farmur
Harv's Avatar
Saskatchewan
Joined Jan 2005
799 Posts
Uh...need a little help. Maybe. Yet another XRB newbie thread...

So here I am, another XRB noob for you vets to snicker at. Got mine today (from www.modelland.com for any other Canucks that are looking) and have a few hopefully new questions and observations.

I came here from flying a Bladerunner and a microblimp, and they in no way prepared me for this little critter. Probably the biggest problem I'm having right now is with the rudder being on the left stick, not the right where I'm used to it. Is there a way to switch the rudder/aileron controls easily? Or should I just get used to it as it is? Anyways...

Did ok on my first flight I think, hovered for a bit and tried some small maneuvers before breaking my first blade on the coffee table when I mixed up the aforementioned controls. I decided to charge the battery fully and laminated a couple sets of blades using Rick's instructions found here while I waited.

The second flight was...interesting. I could hover kinda ok, but after moving around a bit the helo started a severe wobbling. I managed to get it down mostly safely (those laminated blades are a lifesaver) and started reading some more here. Checking the flybar showed it to be balanced, and I found that playing with the blade screw torque gave me a not bad hover with no more wobble.

But now the fun begins. Many times now, when I maneuver around and then let go of or move the cyclic to neutral, the helo will fly in a big (4'-6') counterclockwise circle for one or two revolutions before kinda settling into a hover again. The attitude of the helo doesn't change at all...the nose will stay pointed in the same direction through the movement... but it swoops around like I'm stirring the cyclic in a circular motion.

I haven't touched the trim on the TX or XRB yet as I can keep it (mostly) close to a (sort of) hover as it is, but this doesn't seem to me like this is a trim problem. Could it be rotor wash (I'm flying in a 17x36 attic room with sloped upper walls/ceiling edge), or is there possibly something wrong with my unit or setup?

Any thoughts, input, heckling etc. welcome.
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Old Mar 08, 2005, 10:59 PM
raz
Sportin my new 'do'
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USA, CA, Eureka
Joined Dec 2004
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Hi Harv. I think you are right, it sounds like ground effects. If you get within a couple feet of the floor, walls or ceiling it will move around quite a bit. Also in a small room the longer you hover in one spot the more the air gets stirred up and will cause it to move around more. Good luck and happy flying
raz
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Old Mar 09, 2005, 01:08 AM
I'll Mace You Good!!!
stevenkelby's Avatar
Adelaide, Australia
Joined Sep 2004
906 Posts
Hi Harv,

I got my XRB SR on mode 2 and only fly mode 1. Tried flying as it was but got frrustrated and decided to change it. Its easy to change the controls, just cut and solder the wires. I also moved the throttle to the other side to suit me, not hard, just a spring and bit of metal. Do It! Much easier with what youre used to.

Your problem sounds like rotor wash but a lot of people here have trouble setting there birb up right.

Its mostly all in the manual so read it really carefully if you havent.

Blade balance and tracking is real important.

Any detail questions just ask! This forums helped me immensley, hopefully I can give something back?
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Old Mar 09, 2005, 10:58 AM
Dert Farmur
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Saskatchewan
Joined Jan 2005
799 Posts
Ahhh, much better.

Took my TX to the local electronics guru (I am Not safe with a soldering iron in my hand) and had the wires swapped for the aileron/rudder. Aside from the wires being too short and needing an extension added it looked pretty easy.

But what a difference! Everything seems so much easier and natural now I'm able to fly and crash with total confidence, just like with my BR. Well, maybe not total confidence...knowing this is worth 4x as much keeps me just a bit nervous still when I get close to blade eating things like lamps and furniture. Transitioning between the 3 different units is effortless, and I can simply fly instead of having to concentrate on the different control layouts.

So after 24 hours, this mod, about 4 battery charges, 2 broken B blades and a few popped canopies & flybars I am a 100% happy camper. Now if it would just warm up enough that I could use my 40'x60' shop to fly in I could check on the (possible) rotor wash problem.
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Old Mar 09, 2005, 05:07 PM
Dert Farmur
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Saskatchewan
Joined Jan 2005
799 Posts
Does anyone else hear a quite loud, high frequency sound from their XRB? It seems louder than everything else (motors, rotors etc.) and is bordering on being painfully annoying.

Here's a little audio clip I grabbed...

XRB Audio
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Old Mar 09, 2005, 07:02 PM
Registered User
St. Petersburg, FL
Joined Jan 2005
575 Posts
Sounds just like mine. Mine is new with about 1 hour of flight.
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Old Mar 09, 2005, 08:45 PM
220,221whatever it takes
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United States, IL, Oswego
Joined Jan 2005
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Yep, sounds healthy to me.
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Old Mar 10, 2005, 12:09 AM
Dert Farmur
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Saskatchewan
Joined Jan 2005
799 Posts
Thanks guys. More paranoia and fear put to rest. Earplugs might be optional I guess though.

So I cleared out the back half of the shop tonight (20x25x16H) and I realized that this is the environment the XRB was built for. No more rotor wash/turbulence problems, lots of altitude to play in, no furniture...it was beautiful. Until...

(There's always an until...)

Until I got a wee bit carried away with flying a few circuits. In my defense, the XRB will get up to around mach 1.4 on about the third or fourth lap around a space this big with full forward cyclic, and at that speed there seems to be quite a bit of inertia at the outer end of this centrifuge I had just invented. Sadly the XRB was at the outer end, and juuuust inside the arc it was scribing as it came around the final turn sat my big old radial arm saw and bench.

I'm now the proud owner of some parts.

Or so I thought. Surprisingly enough, after the sawdust had settled I found I was only missing one support strut for the landing skids, the canopy and the flybar. One of the B blades was toast (this was too much for even Scotch Extreme laminating tape), and the skid was broken where the battery tray is attached, but otherwise I was only a couple of minutes away from resuming (slightly less aggressive) flight. I flew out the pack, found the wayward support, dug out the trusty JB Weld and in a few hours everything should be good to go again.

Amazing. Truly amazing. This little helo impresses me more and more every time I fly and/or crash it. Hopefully I won't find some new and improved way to break it for a while though.
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Old Mar 30, 2005, 08:16 AM
Dert Farmur
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Saskatchewan
Joined Jan 2005
799 Posts
I've had a sudden and drastic reduction in flight times, and was wondering if anyone else had anything like this happen to them.

I've now been at this for 3 weeks, and I suppose 35+ flights right now. Lately I've just been flying for 10 mins and then recharging, but now 10 mins is my maximum flight time. I went outside (+5C) this morning with a stopwatch and only managed 6 minutes before it autorotated down when the battery went flat.

I added heatsinks, a battery extension cable and a little flashing light, and my total weight is 207.1 grams, which doesn't seem too high. After the 10 min flight yesterday the little pinion gears on the motors were hot and the battery was warm, but this morning everything was cool to the touch.

Is there something I should be looking for as the culprit here? Or is my battery just dying an early death?
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Old Mar 30, 2005, 10:24 AM
Aspiring novice...
North Central Oro Valley
Joined Dec 2004
143 Posts
Quote:
Originally Posted by Harv
Does anyone else hear a quite loud, high frequency sound from their XRB? It seems louder than everything else (motors, rotors etc.) and is bordering on being painfully annoying.

Here's a little audio clip I grabbed...

XRB Audio
Hard to speak definitively from that audio clip but it sounds just about right to me. If anything is wrong with it, the same thing must have been wrong with mine since the day I received it. (I'm about to install my second set of motors when they arrive from fxaeromodels.com, one of mine appears to be semi-fried... )
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Old Mar 30, 2005, 10:50 AM
raz
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USA, CA, Eureka
Joined Dec 2004
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Flying in the cold does give you shorter flight times. Also are you keeping everything lubed and oiled? For longer motor life the manual says fly 5 min at a time, not the whole pack.
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Old Mar 30, 2005, 11:13 AM
Dert Farmur
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Saskatchewan
Joined Jan 2005
799 Posts
While the battery was recharging I took everything apart and cleaned, polished and relubed the entire drive train. I was able to fly around the living room for almost exactly 8 minutes, and then there was only enough power to hover a couple of inches off the floor for another 2.5 minutes before the LED's flashed and it autorotated down and quit.

I've never bothered to check before, but it needs 75% throttle to hold a hover with a fresh pack right now...does that sound right, or should it be lower? These blades have quite a few flights on them (they're my last set and I'm still waiting for new ones)...could slightly beaten blades cause a 30% reduction in flight times?

The only thing I see in the manual about flight times is that it shouldn't be run continuously for more than 15 minutes (the maximum time for one battery), with a cooling period of 5 minutes afterwards (pg 14). Of course 5 minute flights will be better for everything in the long run, but it's tough to put this thing down when it is (and I am) flying well.
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Old Mar 30, 2005, 12:08 PM
raz
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75% sounds like too much, mine is a little less than 50% If the blades are beat up enough it could be putting more of a load on the batteries but I would think it would not be very stable if they were that bad
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Old Mar 30, 2005, 07:35 PM
Dert Farmur
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Saskatchewan
Joined Jan 2005
799 Posts
Rats. I even resurrected an even more beat up set of blades, and I get identical flight time as before. The helo is dead stable in hover (15-20+ seconds) and in flight, but the air time just...sucks...for some reason now.

I have new blades and a new battery (Rickyblaze) on order, so I guess once one or both arrive I'll find out if either of them is causing the problem. If it isn't one of these though, I'm probably going to be shelling out the big bucks for new motors? Brrrr...maybe I need to start researching the warranty now.
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Old Mar 30, 2005, 08:05 PM
raz
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USA, CA, Eureka
Joined Dec 2004
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The charger may not be fully charging the battery, I would check that before spending over $80.00 for motors. Also, did you happen to fully discharge the battery at some point? If you did you that would explain your reduced flight times.
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