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Old Jul 27, 2008, 08:26 PM
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Mini-Review
Walkera #38 large tandem coaxial

Iím not sure if Iím the first one to get one of these new big Walkera tandems, but I thought I would share some of my first impressions on it.
I couldnít find anyone in the U.S. that had them yet so I ordered one from a China source to add to my heli collection.

First impression is its big!! It dwarfs a regular CX2 sized coaxial and is double the size and weight of the Twister Skylift tandem model. All up weight with battery on this heli is 1 lb 11 oz. Itís the same size as my 450 CP helis. Itís powered by 4 370 size motors. The body on the heli is just a bit thicker lexan than a CX2 and because of this helis weight, a crash from any reasonable height is going to cause some serious damage to it

All the head parts are aluminum and look to be decent quality stuff, but the multi colored anodizing on them is silly for a scale camo military heli.
The electronics are easy to get to and the 2.4 Ghz RX has gyro sensitivity, servo travel, and proportional mixing adjustments. Donít expect much from the manual if you are newbieÖ..its gives only brief descriptions of where the adjustments are located but gives no instructions at all of what they do or what to do if the heli needs adjusting. It easy to figure out of you have prior heli experience.

Now for the bad stuffÖÖ..The heli was in no way flyable out of the box. The blade tracking was way off which caused a vibration in flight with any cyclic command that would almost shake the fuselage off of it. The servo throw was also set to its lowest level which made the heli uncontrollable and there was a severe LT yaw that I had to spend 30 minutes trying to get corrected.
Next issue is this heli is VERY underpowered for its weight. The supplied battery is a 7.4 volt 2200 Mah lipo and 7.4 volts is not near enough juice to power 4 370 sized motors and keep an almost 2 lb heli in the air for long no matter how big the capacity. It takes ĺ stick on a full charge just to hover the heli, so this means you have almost no climb out capability left in the throttle. If you drop the altitude too quickly or get to close to an object you will need a couple of secondís time before the heli can muster up enough power to move away or up again.
Within 4-5 minutes of simple hovering the battery pack has dumped to 3.5 v per cell (lower than I like to go), is very hot (120 degrees on my temp gun) and can no longer keep the heli in the air at all. The Twister Skylift is much smaller yet uses a 11.1V batter for higher headspeed, so Iím not sure what Walkera was thinking when they chose this setup. I have e mailed Walkera to see if these electronics are capable of handing a higher voltage safely. The battery tray is an enclosed ďcageĒ to keep the balance proper, so once again even if a 3 cell 11.1V lipo can be used, this will need to be modified to accommodate it. Something that should not have to be done on a new heli!
The next big issue is the supplied charger must be from their other smaller heli product line. It only charges at a rate .8 amps so charging a 2200 mah batt takes almost three hours!! Luckily I have other chargers and can use a more appropriate 2 amps, but a newbie will need to buy lots of expensive batteries or another charger to overcome this. Three hours charge time for 5 minutes max flight time is not acceptable to me.

I found out quickly that this heli cannot be flown indoors in anything but a very, very large room, or outdoors in light wind conditions. The propwash from the 4 big rotors is incredible and the turbulence around walls or furniture will make the heli uncontrollable. I had the heli hovering I'm my living room about 5 feet in front of me at waist height, and I could feel wind coming down the walls and hitting me from behind like a fan was blowing on me!! The drifting around this causes makes the gyro go nuts and only makes the heli control worse. Also this is my first experience with a tandem heli so one thing I noticed is the cyclic response is very slow and movement occurs a second or so after you input the command. This Iím sure is just due to the helis weight and tandem design, but factor this in with severe indoor turbulence drift and you will not be able to keep the heli in one place. I turned up the servo travel thinking this would give me more responsive cyclic, but it also causes the heli to start a very bad ďsee sawĒ type wobble nose to tail anytime you give fore or aft cyclic. The cyclic throw needs to be very slow to keep the heli in balance in the air so I turned the travel back down. It takes almost full cyclic stick to move the heli and the direction changes are slow (another reason to be in a very large space!!)

Itís a great looking heli but in its stock shipped form itís far from being a sound RTF model and something needs to be done about the power issues and hot lipos.
For now itís just going to be a shelf queen in my collection until I can see if I can safely get the headspeed up and see if I can reduce the stress on the batteries trying to keep this thing in the air.
I feel Walkera would have to know this heli was underpowered from factory testing, and why they chose to release this heli this way is beyond me. It is a good looking scale heli and is very cool in scale appearance what little time it will stay in the air.
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Old Jul 27, 2008, 08:50 PM
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Great review Xrayted!

I've had a Skylift pre-ordered from HL since they made the offer but it still looks like another month until they are available.

I considered the #38 but was waiting to hear more. Looks like the release was premature. That is very heavy and looks like it will be Walkera-only parts.

Let us know what improvements you make. I'm waiting for the Skylift to compare to my dual CX2 tandem and I think between the two, I can get a pretty light and responsive small tandem in the air, especially with NE rotors. Love to see what can be done to make the larger #38 better.

BTW, any experience with the metal 2.4 4#3? Ordered one Friday and should be here Wednesday.

Regards
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Old Jul 27, 2008, 08:57 PM
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Originally Posted by rbinc
Great review Xrayted!

I've had a Skylift pre-ordered from HL since they made the offer but it still looks like another month until they are available.

I considered the #38 but was waiting to hear more. Looks like the release was premature. That is very heavy and looks like it will be Walkera-only parts.

Let us know what improvements you make. I'm waiting for the Skylift to compare to my dual CX2 tandem and I think between the two, I can get a pretty light and responsive small tandem in the air, especially with NE rotors. Love to see what can be done to make the larger #38 better.

BTW, any experience with the metal 2.4 4#3? Ordered one Friday and should be here Wednesday.

Regards
Thanks rbinc! Yeah they didnt think this one through. Its a great looking heli but Im afraid to just connect up one of my 3 cell packs to it yet until I can get some more info from Wakera. All I need is to fry the electronics in it the first week I have it. The rotors are bigger than anything else out there, so for now other brand blades or aftermarket parts are not an option. Im hoping to go with 11.1 V and the Xtreme 380 motors which i here make fantastic power just like the smaller second generation 180's I have.
I do have a metal version 4#3 and its great. Depending one which version you have from before, the new one has a larger main gear and lower headspeed, but bigger blades. It also has rubber dampeners in the head and a tiny little feathering shaft. Its much more stable and very easy to keep in one spot for any experienced flyer. I have both the new and old 4#3 and the new one will hover in ground effect much better and doesnt wander all over the place like the higher headspeed one does. They pretty much fly right out of the box and its one of my favorite helis.
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Old Aug 16, 2008, 09:04 PM
canicrashhere2
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willoughby ohio
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wow am i glad to find you

xrayted i feel your pain i have had my 38 for about 3 weeks.i have been looking for someone to talk too, to try and figure this heli out.i'm not having the same problem with the battery it will charge in less than an hour and for sure gives me more than 5mins. flying time.maybe your batterys bad,chargers bad or theres a short in the heli itself?i hope this can help, e-mail walkera tell them about the problem somethings bad from the manufacturer.well i just joined this site, just because i saw your post if theres any info you can pass on please do and i'll be happy to compare notes with you anytime.
CAN I CRASH HERE TOO why not i have crashed everywhere else!!
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Old Aug 16, 2008, 09:42 PM
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Originally Posted by canicrashhere2
xrayted i feel your pain i have had my 38 for about 3 weeks.i have been looking for someone to talk too, to try and figure this heli out.i'm not having the same problem with the battery it will charge in less than an hour and for sure gives me more than 5mins. flying time.maybe your batterys bad,chargers bad or theres a short in the heli itself?i hope this can help, e-mail walkera tell them about the problem somethings bad from the manufacturer.well i just joined this site, just because i saw your post if theres any info you can pass on please do and i'll be happy to compare notes with you anytime.
CAN I CRASH HERE TOO why not i have crashed everywhere else!!
Thanks. I actually have mine torn down now and all four motors are being replaced with the Slo Max 300 with heatsinks. This is a popular replacement motor for the HPFP guys and they are more powerful than stock.
I am waiting on getting some 9T pinions as the stock 11T will be too much with these motors. Hopefully the 9T will make all run a little cooler than the stock setup and give me some better torque with this heavy heli.
I have also changed to a DN 7.4V 2150 Mah battery which fits the stock tray perfectly and has a 15C rating. I get 6-7 min flights with it and the battery is just a warm 100-110 degrees or so which is no different than any of my other helis after flight. I have done several flights with an 11.1V 1800 Mah 3 cell as well......tons of power and the same flight time, but the motors are screaming hot!

I will post some pics and build info after my pinions are here for me to experiment with and find the correct gearing combo. I plan to to do a flight time, motor and battery temp comparison with my IR temp gun after using 9,10 and 11T pinions on the new motors, and see which combo gives the best flight times vs. the coolest running setup on the batt.

The weight of the heli also causes it to suddenly decrease altitude when hovering, everytime the gyro makes a command on the upper rotors to slow down or a yaw command is givin. I find myself fighting to try and keep the heli in one place with the throttle and then suddenly the upper rotors are commanded by the gyro to speed up and then the heli is now bouncing up too high again. The plastic rotors can barely handle the weight of the heli so any change in rotor RPM at all will cause the heli to drop altitiude. I need to try and find a more efficient substitute to deal with this after the motor changeout.

I dont see how you can possibly be getting your stock 2200 Mah battery charged in less than a hour on the stock .8 amp charger????? Its mathematically impossible even with everything is working just fine Unless you are barely flying any charge out of the battery to begin with. My stock battery charges just as it should on my DN charger at a rate of 2 amps and takes just about 45-60 min to charge at that rate depending on how long my flight was. My charger that came with the heli is fine......its just for a 800 Mah pack and not the one that this heli uses but I have many others anyway so no big thing to me. Welcome to the forum and will be glad to pass on anything I learn along the way on this one Crash

Happy flying!
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Old Aug 17, 2008, 08:58 PM
canicrashhere2
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willoughby ohio
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time to time some flight

you know i have never timed my flight time on any of my helis i just fly to the packs gone.but your right i should be doing it so i started out today with full battery and timer on just flying it back and forth easy when for no reason my front swashplate came apart big time!!CRASH BROKE EVERY BLADE AND ONE FLYBAR.goodthing i'm use to crashing helicopters so no big deal.but a timed flight will have to wait.if you find a hobbyshop that won't make me pay for a private jet to fly my parts here please let me know.i never had a walkera product before are they just junk or did i happen just get the one bad swashplate?keep on smilling today is a great gift
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Old Aug 18, 2008, 04:44 AM
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Quote:
Originally Posted by canicrashhere2
you know i have never timed my flight time on any of my helis i just fly to the packs gone.but your right i should be doing it so i started out today with full battery and timer on just flying it back and forth easy when for no reason my front swashplate came apart big time!!CRASH BROKE EVERY BLADE AND ONE FLYBAR.goodthing i'm use to crashing helicopters so no big deal.but a timed flight will have to wait.if you find a hobbyshop that won't make me pay for a private jet to fly my parts here please let me know.i never had a walkera product before are they just junk or did i happen just get the one bad swashplate?keep on smilling today is a great gift
Sorry to hear about the crash. Walkera is not really stocked locally by any hobby shops. You will need to mail order the parts. I was one of the first to get one of these things so I ordered minr from China from here: His servic is great and I have never had any issues with him. http://www.chinesejade.com/walkera38.htm
You are pretty much stuck with waiting 10 days or so for parts until any of the local U.S. e-tailers have them (assuming you are U.S. based) and so far I know of no one in the U.S. with this heli or parts yet, but I may be wrong.
Terrence only charges 5 bucks for worldwide shipping on anything no matter how big or small.
The swash is pretty heavy duty on these things although the little ball links have only about one or two threads screwed into the ally. I removed all of mine and then used threadlocker on them. Walkera has a jaded history with their helis but it was more for the electronics than anything.
Dont fly your lipos all the way dead or they can be killed very quickly and not take a charge. Its generally best for a lipo to only be drained 20% of each cells capacity for longest life and never below 3V per cell or they are gone.
On my 2 cell packs I like to leave 3.5V per cell or more after flight or 7V total in this helis case. Thats about a 5 minute flight on this heli with stock battery

Good luck crash
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Old Aug 19, 2008, 06:52 PM
canicrashhere2
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willoughby ohio
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thanks for the hobbyshop info

when i saw that he shipped that helicopter for $5 MY HEART SANK.i paid $46s+h from miracle-mart.com!!but looking closer jade wants $238+$5 makeing the cost $243 miracle-mart wants $199+$46=$245 so its about a wash.i see this all over the place i can't find a real deal out there they always seem to be with in a few bucks.but thanks for hipping me up, you can be sure when i saw that $5 i was screaming NOOO!Anyhow i got the 38 torn down i love to see how things work makes my day.what do you think i should do e-mail the picture of my blowin out swashplate to wakera or miracle-mart and do you think anybody will help me out?let me know what you think, over and out Xrayted i think i'm going to crash latter
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Old Aug 19, 2008, 07:28 PM
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Originally Posted by canicrashhere2
when i saw that he shipped that helicopter for $5 MY HEART SANK.i paid $46s+h from miracle-mart.com!!but looking closer jade wants $238+$5 makeing the cost $243 miracle-mart wants $199+$46=$245 so its about a wash.i see this all over the place i can't find a real deal out there they always seem to be with in a few bucks.but thanks for hipping me up, you can be sure when i saw that $5 i was screaming NOOO!Anyhow i got the 38 torn down i love to see how things work makes my day.what do you think i should do e-mail the picture of my blowin out swashplate to wakera or miracle-mart and do you think anybody will help me out?let me know what you think, over and out Xrayted i think i'm going to crash latter
You should try and take it up with Miracle Mart but they can always come back and say you did the damage in a crash....not crashed because of it.

That is why Terrence is about the only guy I will order things from China from with the exception of Deal Extreme. He is in the forums all the time, always repsonds to e -mails very quickly and has never screwed any of us who have dealt with him over. Its hard to get anywhere with the larger Chinese depots when there is an issue.
I hope MM will help you but if not, then get yourself some new parts for it from Terrence at Chinese Jade shipped for cheap and know that you have a good, honest parts supplier that you can talk to from now on if you have issues
BTW the 238.00 price from Terrence already has the 5 bucks shipping included in the price! I have ordered from him 6-7 times and shipping to East Coast U.S. has never been more than 10 days so far for anything.
Good luck Crash
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Old Aug 20, 2008, 10:41 PM
canicrashhere2
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guess i'll give him a try

I think it will cost me about $90 to get her back up with some spares, like extra flybars i will shorten to see if it makes the heli more responsive.do you think thats worth a try?I'm going wait to order the parts to i have it all apart who knows what else i might break.please excuse my grammar i'm a long way from my last english class and i mostly read threads i don't partake.
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Old Aug 21, 2008, 12:16 AM
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Originally Posted by canicrashhere2
I think it will cost me about $90 to get her back up with some spares, like extra flybars i will shorten to see if it makes the heli more responsive.do you think thats worth a try?I'm going wait to order the parts to i have it all apart who knows what else i might break.please excuse my grammar i'm a long way from my last english class and i mostly read threads i don't partake.
Im for trying anything, but Im not sure I would shorten the flybar for this helis.
It is supposed to move slow and scale like and the long heavy flybar is what keeps it stable.
Try adjusting the servo extent pot on the RX first. It will change the servo throw and make the cyclic commands much more robust. As a matter of fact, I turned mine up very high once and the cyclic commands were too much for this big heli, so Im not sure the lighter flybar mod is really needed at all here.
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Old Aug 21, 2008, 11:53 AM
www.rccommand.com
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Originally Posted by Xrayted
Within 4-5 minutes of simple hovering the battery pack has dumped to 3.5 v per cell (lower than I like to go), is very hot (120 degrees on my temp gun) and can no longer keep the heli in the air at all. The Twister Skylift is much smaller yet uses a 11.1V batter for higher headspeed, so Iím not sure what Walkera was thinking when they chose this setup. I have e mailed Walkera to see if these electronics are capable of handing a higher voltage safely. The battery tray is an enclosed ďcageĒ to keep the balance proper, so once again even if a 3 cell 11.1V lipo can be used, this will need to be modified to accommodate it. Something that should not have to be done on a new heli!
Hello Xrayted - very good review. Thanks for sharing your findings. We have our first shipment of these on the way to us, which we hope to have in about 10-12 days or so. Did Walkera ever respond to you on your battery question? I see that you've already gone to another battery that seems to be a vast improvement for the heli in its otherwise stock form - but I'd like to hear what they had to say about this and possibly other issues you my have mentioned to them.

Thanks again,
Bill
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Old Aug 21, 2008, 03:24 PM
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Hello Xrayted - very good review. Thanks for sharing your findings. We have our first shipment of these on the way to us, which we hope to have in about 10-12 days or so. Did Walkera ever respond to you on your battery question? I see that you've already gone to another battery that seems to be a vast improvement for the heli in its otherwise stock form - but I'd like to here what they had to say about this and possibly other issues you my have mentioned to them.

Thanks again,
Bill
No response at all Looks like we are on our own here and the Twister Skylift guys seem to be having the same issues. I just went ahead and tried a 1800 Mah 3 cell that I had which was close to the same foot print of the stock battery but a little thicker of course. I was able to still secure it into the stock tray (tight fit) and made about 7 flights with it with no electronics failures.
The power difference was noticeable as one would expect. You could hover at mid stick instead of 75% like the stock battery and the flight times were close to the same and no battery heat issues. The motors were scorching hot though and probably would not last long at all so I've decided not to go the 3 cell route at first anyway
The DN 15C 2150 2 cell drops right in and runs much cooler with flight times about 5-7 minutes which is about the max for these helis. Im assuming its a higher C rating than the stocker that comes with the heli.
Im traveling for the next few days but have 4 Slo Max 300 motors with a few pinion gear choices that I plan to try in various combinations to see what the best power/heat combination I can get with the heli and I also have some Honey bee heat sinks that look like they will work and fit in the fuselage.
As soon as I can get home to run some test I will report back with what seems to work best
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Old Aug 24, 2008, 09:16 PM
canicrashhere2
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Xrayted Can U Help Me Here

reading your post you are a regular Glen H. Curtiss at least to me you are.I want to talk myself into pressing the swashplate back together i have read posts that say to do it.but i'm not sure of which helicopter they did that with,or if it would really work?the few times its happen to me i just bought a new one, don't need anymore crashes.I never had a metal one go before.by the way your right about the flybars i need alot more flight time before i start fooling with that.let me know on your take on the swashplate.thanks
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Old Aug 24, 2008, 10:12 PM
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Originally Posted by canicrashhere2
reading your post you are a regular Glen H. Curtiss at least to me you are.I want to talk myself into pressing the swashplate back together i have read posts that say to do it.but i'm not sure of which helicopter they did that with,or if it would really work?the few times its happen to me i just bought a new one, don't need anymore crashes.I never had a metal one go before.by the way your right about the flybars i need alot more flight time before i start fooling with that.let me know on your take on the swashplate.thanks
Ive never had a CNC swash seperate on me before. The plastic ones will just snap back together, but I have no experience with getting one of these back together, or if it can be done. Maybe someone else will see your issue here and chime in.
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