Originally Posted by Mark Chance

naturally i got the 5 sets of blades for 16 bucks dohicky 2x LOL..

Cool!

Unfortunately, my local LHS doesn't even stock the mcpx yet... well, wait, they finally did get some.... LAST WEEK. So they are not the best source for heli parts... seem to focus on dolls, plastic models and RC cars.

Originally Posted by ojo

Hi Jack,

I fly the 4f200 with a 2702 RX, MKS DS470 servos, better motor and YGE30 ESC and it is night and day compared to the stock configuration. I have also a GAUI X2 with uBeast and they are both very similar now. The Gaui tail is much better, but that is it.

Regards, Ojo

I am wondering if the 2702 has enough extras and better operation vs. 2618 to justify costing double what a 2618 costs?

I am guessing the 2702 is roughly equivalent to the 2618 in performance.

If the 2702 is better than the 2618, what are its advantages?

I would really appreciate knowing your opinion if you have had experience with both.

Thanks - Jack

Originally Posted by tracknoob

This is how high it was when the uncontrollable piro started...luckily, I was already on a gentle decent path, so I held collective position and I instinctively did not alter the cyclic position as it came down. If I had been unlevel when this happened, it might have been worse, but as it was, all the energy was in rotation, not in extra vertical motion.

Just for the heck of it, I fired up the simulator and selected HBKII since it's a 200 sized heli, and the sim does not have the 4f200 as a model.

I put the heli at a pretty good height, then I started a slight decent with the heli level, and then I thumbed in full left rudder. As it piro'ed downward, I just held both collective and cyclic position, and I'll be darned if even while in full piro, it landed without a crash, and I was able to take off again.

Obviously, loosing a tail rotor is a major incident, but it seem that if the model is well-balanced and does not require you to put in cyclic to keep it level as it spins, a recovery without damage is possible - obviously, you have no directional control, so that's assuming the path is clear underneath.

While I still had the HoneyBee King II model loaded in the sim, I tried to pull off an autorotation, since lately I've been trying that on the larger nitro simulation models. At first it seemed no technique I tried, including very high altitude, and forward flight, and various settings for collective were going to let me do it. I noticed my HBKII does have a one way bearing on it, so it is set up to at least *try* to auto, so I kept messing with it. Eventually I found that with *some* forward motion, but not too much, and a rapid full-down collective (in normal mode), I could get enough blade speed that if I then popped full positive collective moments before the ground, I could just get it to settle down without a crash. But it's a narrow window on that simulator. I guess with not much blade/head inertia, it's likely very similar in real life.

Anyone out there ever auto a HBKII in real life?

Originally Posted by ChopperJack

I am wondering if the 2702 has enough extras and better operation vs. 2618 to justify costing double what a 2618 costs?

I am guessing the 2702 is roughly equivalent to the 2618 in performance.

If the 2702 is better than the 2618, what are its advantages?

I would really appreciate knowing your opinion if you have had experience with both.

Thanks - Jack

I will just contribute to price, normaly is around $130. But searching you can find far better prices. I got one from miracle mart for $85 for a 450 build
http://www.miracle-mart.com/store/in...oducts_id=6763
just put your email to stock alert if you are interested.
RX2702V is supposed to be the flagship 3G of Walkera, for now.

Yes Miracle-Mart always offer great prices for heli parts, but these days due to their excellent pricing they are often nil stock, just like Hobby-King.

Yeah, let us buy in good prices and as long as they see products selling they will stock.
It was also myrcmart http://www.myrcmart.com/walkera-heli...sort=4a&page=1
They killed their 4F200 stock at these prices!
I wanted to buy the head parts but lost the timing.

Originally Posted by ChopperJack

I am wondering if the 2702 has enough extras and better operation vs. 2618 to justify costing double what a 2618 costs?

I am guessing the 2702 is roughly equivalent to the 2618 in performance.

If the 2702 is better than the 2618, what are its advantages?

I would really appreciate knowing your opinion if you have had experience with both.

Thanks - Jack

Hi,

in my opinion it is night and day. The 2702 uses a 16bit microcontroller compared to the 8 bit in the 26xx series and I think Walkera put the additional processing power to use. For example, the 2702 has some kind of piro compensation, which the 2610 and the 2616, which are the two rxs I have flown, definitely not have. The 2702 also has antenna diversity, making the rx-link much more secure. In addition, the 2702 allows electronic swashplate trimming, gyro direction selection and individual endpoint adjustment for the tail servo.
For me, the main disadvantage of the 2702 is that you can not use it with a spectrum satellite, so if I want to use my MCPX I have to carry two Txs to the field. For me, this was the reason to put a ubeast inside my M120D01 (for more information look at the M120D01 thread at Helifreak).

Best regards, Ojo

Originally Posted by ojo

Hi,

in my opinion it is night and day. The 2702 uses a 16bit microcontroller compared to the 8 bit in the 26xx series and I think Walkera put the additional processing power to use. For example, the 2702 has some kind of piro compensation, which the 2610 and the 2616, which are the two rxs I have flown, definitely not have. The 2702 also has antenna diversity, making the rx-link much more secure. In addition, the 2702 allows electronic swashplate trimming, gyro direction selection and individual endpoint adjustment for the tail servo.
For me, the main disadvantage of the 2702 is that you can not use it with a spectrum satellite, so if I want to use my MCPX I have to carry two Txs to the field. For me, this was the reason to put a ubeast inside my M120D01 (for more information look at the M120D01 thread at Helifreak).

Best regards, Ojo

Thanks for letting us know this great information. I'm curious to know your source and thankful to have learned more.

While searching the great prices at miracle-mart (probably should be lucky-mart I stumbled across the 2618V-D which is latest greatest installed in the latest greatest V200D03 which I am told is a two blade version of the 4f200. The "D" version receiver is flash upgradeable. Walkera is theoretically offering some sort of upgrade deal through the dealers to replace old receivers.

Also, the RTF comes with the new Devo Tx. It says it has seven adjustment points on throttle and pitch curves which might be good. I am assuming this might not apply to older Rx and maybe the "D" stands for "Devo?"

Jack

Greetings all, I my have discovered why my two LiPo batteries for my 4f200 have become puffy about the same time but different age batteries. After flying my 4f200 last night, I noticed extreme heat from the ESC and motor both of which are close to the battery. Everything is mounted in such a way as to allow all that heat to funnel up across the end of the battery. In the past, I would just leave the battery in place and charge it there too. I have been noticing it seemed to take longer to charge this battery after cool down. I just thought maybe it had something to do with the fact it wasn't laying flat and that may be the reason - I dunno.

At any rate, I think these two puffy batteries are basically good, just puffed up by exposure to excessive heat. Batteries are getting removed after flight from now on!

Jack

If you are charging on the model, you must have one big 'Lipo Safe' bag to fit the whole heli into!

When people talk of lipo safety, they always talk about removing the battery from the model before charging/transporting/storing, and they'll tell you to go to YT and watch a few vids of lipo fires, and/or search the treads here on rcg for folks who have accidentally caught their houses on fire. I don't want you to think I'm scolding, but it's a big deal, IMHO.

Happy Friday,

Rafa

Originally Posted by ChopperJack

Greetings all, I my have discovered why my two LiPo batteries for my 4f200 have become puffy about the same time but different age batteries. After flying my 4f200 last night, I noticed extreme heat from the ESC and motor both of which are close to the battery. Everything is mounted in such a way as to allow all that heat to funnel up across the end of the battery. In the past, I would just leave the battery in place and charge it there too. I have been noticing it seemed to take longer to charge this battery after cool down. I just thought maybe it had something to do with the fact it wasn't laying flat and that may be the reason - I dunno.

At any rate, I think these two puffy batteries are basically good, just puffed up by exposure to excessive heat. Batteries are getting removed after flight from now on!

Jack

Originally Posted by ChopperJack

Thanks for letting us know this great information. I'm curious to know your source and thankful to have learned more.

Hi Jack,

it is quite simple: I opened up the rx and looked at the chips The rest I know from flying two 2702 in a 4f200 and a V120D02.

Regards, Ojo

ChopperJack.

Check 2 things on this overheating... YOur main gear mesh with motor pinion maybe too tight or belt too tight.. this would cause drag on the motor overheating ESC and then Battery pack.

also check your swash ball make sure its free and loose, it maybe gummed up with junk and causing friction as well (simply take off swash and lube the ball and spin it around until its very free and smooth.

Rafa,

Alot of people dont know what a lipo can do when it gets punctured or swells so much that the seams of its casing opens and the material inside reacts with air.

I've had a 6 cell go off on me, boy you would swear i was in rocketry LOL 6 times it went off 1 for each cell, i dont even think plasma cutters make that much heat and sound.

Mine happened while i had it charging (yes it was puffy but i kept using it) i heard a little pop while me and my bro was playing cards and i knew instantly something was wrong... i had it in a large dish just in case somethign like this would happen, i had just enough time to unplug it and toss the thing outside on the driveway, then she went off like crazy!

would have been disastrous if it went off and sitting on anything but metal or concrete.

Originally Posted by ChopperJack

I noticed extreme heat from the ESC and motor both of which are close to the battery. Everything is mounted in such a way as to allow all that heat to funnel up across the end of the battery.

Jack

I think most of us who try to fly this on a more-or-less regular basis have *both* upgraded the ESC (and relocated it an outside frame rail), as well as adding a separate UBEC to lower the stress on it.

On most small helis, you'd be worried about what that kind of stuff would do to weight and performance, but as anyone who has one of these hotrods can attest, this little porker is already sittin' heavy stock, but has no trouble at all hauling butt in either configuration.

Originally Posted by Mark Chance

Rafa,

Alot of people dont know what a lipo can do when it gets punctured or swells so much that the seams of its casing opens and the material inside reacts with air.

I recently had a relatively new original Walkera 4f200 battery get puffy on me, not while flying, but after I left it in the truck. Dang, lesson learned, it gets too hot to leave the lipos in there while flying. So I really hated to give up on it, since clearly the stress was from a lone-time ambient thermal overload, and not from internal issues or electrical over-stress or age/break-down....

I read up on it, including both very-vocal ends of the spectrum; both the horror stories with scare-tactics, as well as the shoulder-shrugging "wait 'til it does something' "I've flown puffy batteries lots of times" types.

At the end of the day, I got on line, ordered a couple of new ones, and with that done, did the difficult task of snipping the leads off a $20-something dollar battery that was *probably* still usable and just chucking it.

My analysis was simple: Do you really want to risk this thing going up and endangering your heli, or a lot worse?

No, I do not.

Case closed.