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01-14-2006 12:32 AM  13 years ago
HELIWIZARD

rrApprentice

ardsley, new york

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dave
i didnt mean anything bad at all in what i wrote. i also like all the things you have tweeked on the heli and doing the play by play. so other people, reps and the engineers can learn. i just think out of all the electrics this has been the best i have ever flown and owned with out all the tweeking and crap. as for the 3D issue (i might be wrong) but isnt a roll and loop considered 3D. the heli can handle that. but it wont stand up to the pressure of doing tick-tocks, funnels and all that other 3d stuff the trex will do after a thousand dollars lol. and besides kyosho has been know for years for there electric r/c cars and if they havent found or created a motor yet i really dont understand the need to try to figure it out. basically what i am saying i have been in r/c for along time have seen some great cars and stuff out there and once the bashing starts it gets pulled off the market. i just dont wanna see that happen here cause i really enjoy this heli.
thats all
rick
ADDICTED TO HELIS ~ too much FUN
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01-14-2006 01:51 AM  13 years ago
dkshema

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Cedar Rapids, IA

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I looked briefly at some T-Rex blades. I happen to have a set of the Align Carbon Fiber TR blades just waiting to be installed on one of my Rexes.....

What stopped me is the size of the hole in the root. It's small and the area around it isn't much larger. Align uses a smaller diameter bolt for the TR blades than the EP. I thought about drilling out the holes, but wasn't sure about what that would do to their integrity. I also didn't check the root thickness, so I'm not sure if they are similar to the EP. One thing I like about the EP TR system is those little plastic spacers for the TR grip and the blade. It's nice touch.

If I could find some suitable TR blades, I'd give them a try. There are quite a few small electrics these days, and I haven't bothered to keep up with all the different makes and models, so keeping track of what might fit the EP from a different heli is difficult.

I'm still going to give the TR assembly the ice-cube balancer treatment to see how well balanced the assembly is now that it doesn't shake. Then I'll compare those results to that of my High Point Balancer.

Dwight has hinted at a list of some very nice upgrades that are coming along for the EP...the list sounds like it will be some very worthwhile upgrade stuff -- I hope that the parts aren't priced out of the range of mortals, like many of the Kyosho "HG" upgrades for the Caliber 30 seem to be. What I'd like to know is when these upgrades will be available -- and if some good close-up pics of them will be available soon.

There are so many things I'd like to try with this little heli, but they all cost $$$. I don't want to end up spending a fortune just experimenting! The appetite of a small fleet of helis is enormous, and keeping them all well-fed and happy is a full-time job!

Dave
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01-14-2006 03:33 AM  13 years ago
Caliber1

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Fort Worth, TX

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Thanks to you Dave for turning over all of those stones, and telling us whats underneath them. I, for one appreciate, your relentless root cause assessment, and your honest feedback when things work, and when they don't work. Hopefully the manufacturers are looking here and paying attention to what is written.

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01-14-2006 04:35 AM  13 years ago
dkshema

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Cedar Rapids, IA

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FWIW --

I removed the TR assembly from the EP this evening, and adapted the Ice Cube balancer that Raptorrecker had posted on his gallery in conjunction with balancing fans and flywheels. This was done to double check the balance I got with my High Point balancer.

The two pics below show the final balance of the tail rotor assembly that make the tail on my EP run smoothly:

Prior to adding the pieces of tape, my High Point would allow the assembly to stop at any position and hold that position, showing that the assembly was correctly balanced. Now, with the ice cubes, you can see that one the assembly is unbalanced...this is the only position it will hold.

I whipped out the High Point and the results were the same, at least letting me know that the balancer does its job.

So -- it appears that the proper way to balance the EP tail is simply trial and error, using bits of Trim MonoKote or some other form of tape. And the moral of the story is --- what appears to be a finely balanced system, may not be!

Dave
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01-14-2006 04:57 AM  13 years ago
Dwight

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West Chicago, IL

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"once the bashing starts it gets pulled off the market"

If a manufacturer has made a committment to bring a new product to the market, and it is selling well, they are not going to pull it from distribution because it has some growing pains. There are always problems with any product on the market. Some are worse than others but nothing is perfect.

What brand of helicopter do you know that this has ever happened or are you referring to cars?

I would like to share this story because it is my personal reason for defending any new product until proven unworthy. Back in the early 90's there was a machine released on the market called a Concept 60. No one took this machine serious because it was made of all plastic components. One of the current top 3 pilots in the US made this comment at a fun fly in 1992 "No one will ever take that machine serious because it is made of plastic. If you want to get serious about competition you are going to get a different brand helicopter." I spent 3 years working with this machine figuring out what worked and what didn't meanwhile practicing FAI competition with it. In 1995 I made the US FAI F3C team with that machine and attended the World Championships in Japan. At the end of the preliminary rounds that machine performed well enough to earn me a 3rd place standing out of 47 of the top pilots in the world. In the finals I did not fly as well and fell back to 5th place. For a machine that supposedly nobody would take serious I guess I proved them wrong.
My point is that the Concept 60 appeared to have many problems but they needed a solution. In the beginning it wasn't even considered an equal to everything else on the market. In the end it was really as good or maybe even better with a little work. It had a good platform to start with but needed tweeking.
If we apply this idea to the 400 imagine what it will eventually be.

Dwight
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01-14-2006 05:16 AM  13 years ago
Caliber1

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Fort Worth, TX

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So -- it appears that the proper way to balance the EP tail is simply trial and error, using bits of Trim MonoKote or some other form of tape. And the moral of the story is --- what appears to be a finely balanced system, may not be!
Ok, a correctly balanced MR/TR "should" work but doesn't on this one. It was balanced, now its "tuned". I wonder why is it not vibrating now? Blade CG issue? Additional weight changed harmonic frequency enough to keep it out of range? If this were the case, tape on the other blade would accomplish the same thing, and I believe that you put tape on the other blade and vibs got worse. Now, the big questions is, What is Kyosho going to do to correct this problem? Sounds like possibly a design issue that they did not consider for the head speeds that you are running at. Be interesting to see what happens if you decide to run even higher head speeds.
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01-14-2006 06:26 AM  13 years ago
HeliK

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SoCal

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My C400 really did not have severe vibration in the tail. I just did what Dwight said and used a piece of scotch tape on the TR, spun the head up with the main blades off and about 5 different tests with a bit of tape added and now no vibration. I got rid of the vibe in less than 5 min of messing with it. Good at any headspeed I use.
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01-15-2006 05:24 AM  13 years ago
dkshema

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Cedar Rapids, IA

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Grrrrr.....

A few posts back, I said the EP runs hot and cold. Thursday PM, it was hot, today it's back to cold again. The EP400 is the first helicopter I've ever seen that suffers from Bipolar Disorder.

The tape thing on the TR -- worked for a few flights. The vibe is back, bad as ever, and I've been dorking around with this bird all day long to figure it out. The tape trick doesn't work, a balanced TR doesn't work.

I'm now in the process of dropping the number of teeth on the pinion to get the speed back down. Currently my 450TH is running a 29-tooth pinion, down from the 32-tooth.

It's time to put a small pinion on, put in a dismal motor, and get the head speed to just above the wobble speed, and resign myself to the fact that this heli has a severe problem with the tail-rotor system design, and that it will be just a fly around the field but don't do much of anything chopper.

The tail rotor system is the Achilles heel of the EP 400. NO heli should be this picky, this sensitive, or this unforgiving.

Until (UNLESS???) the TR design is radically modified, the EP will never reach its full potential. It will never be able to live up to the ad copy I posted a few posts back with this tail rotor system.

One of my initial posts had a shopping list of improvements that Kyosho should do to make this a better chopper. Ball links on the MR controls instead of Z-Bends, reinforced roots on the MR blades...those are nothing unless the tail rotor system is fixed. This is an absolute, MUST, in my opinion.

Something on the rear-end is just not up to the task of running smooth at a decent RPM. Above a certain RPM (I don't know what the magic number is), the tail rotor shaft begins flexing. When it does that, it's all over. The shakes go huge, the gyro and receiver begin to act up from the severity of the shaking, and you have to shut down the heli.

Why the flex? Is the stock TR shaft too soft? Is the TR shaft too flexible? Is the hub machined off center? Are the TR shaft bearings too close together, and not providing adequate support for the shaft? Is the plastic TR case itself too soft and flexible? Is the use of a single set screw in the hub enough to throw the balance of the TR off at higher speeds? Is the D-shaped aluminum driver for the TR pulley out of balance enough to cause the vibes? Is there one or more bad bearings in the rear? Is there a combination of the stuff listed above working against the TR system?

I removed the stock TR blades, and replaced them with a set of T-Rex tail blades from my T-Rex V2 (the V2 is now sporting those CF blades I had). I drilled out the hole, put the blades on, and got two successful hovering flights out of the heli this afternoon, nice and smooth. On the 3rd try, the darn thing went back into the self destruct vibe mode. It's been that way the rest of the day.

Again, remove the TR blades, this thing will turn high RPM all day long, smooth as silk. Put a set of TR blades back on, it would make a great paint shaker.

Maybe the EH64 TR shaft that Chris (RC Heliworks) has mailed will arrive Monday or Tuesday, and maybe it will make a difference. I certainly hope so, otherwise, I'll have an EP400 for sale, cheap!

If the EH64 doesn't do the trick, the EP will be one of the most disappointing helicopter kits I've ever owned -- just slightly better than the American RC Helicopters Revolution 40 I bought back in 1976. That was a heli that NEVER actually flew, no matter what you did to it. The Revolution 40 broke a lot of things...main rotors, tail rotors, MR shafts, gears, skids, side frames, etc. The only thing the Revolution NEVER broke, was free of the ground!

At least the EP400 has gotten off the ground and flown.

Thinking about buying an EP400? Think long and hard before you do. Then take a second look at the T-Rex XL. Maybe in a year, if Kyosho steps up to the plate, the EP400 will be a fine little heli. If Kyosho does nothing and just tries to sell the kit as-is, the EP400 probably won't be around this time next year, it might be lucky to survive past mid-summer. The EP400 has the potential to give Kyosho the biggest black-eye it's had since the introduction of the ill-fated Nexus Legato four-stroke powered heli. Can anyone say "dog?" Owooooooooooooo!

Eagerly anticipating the arrival of the EH64 shaft, hoping against hope that it will be the cure.

Dave
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01-15-2006 05:39 AM  13 years ago
ozace

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melbourne, australia

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Dave, i hope you end up with some success. You have more patience than I. Lucky for me i dont need any single heli to perform, there is always another that will. May be Kyosho will redo their copy and call this the classy E trainer, at lower HS mine it terrific, nice and smooth and docile. If there is no expectation of performance there is no let down.

Good luck with the new bits.
we can never have too many, can we ?
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01-15-2006 04:59 PM  13 years ago
dkshema

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Cedar Rapids, IA

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If there is no expectation of performance there is no let down.
True, but why bother to buy it then?

I'm VERY close to saying "stick a fork in it, it's done." But the fact that I've put down a big hunk of money on this little bird won't let me give up too easily. The kit was $269, but I also bought motors, a speed control, gyro, servos, receiver for it, and have almost as many 64 pitch pinions as my local hobby shop does! I can use the GY401 in a larger heli. And the rest of the bits I guess would go into a new T-Rex XL (or maybe a 3D foamy plane)-- but that still leaves me with a heli that I bought, that may not be usable, nor saleable once the word gets around.

I still want this heli to work, so I'll continue to work with it. But if the ultimate solution is a heli that goes whirr and not much more...it will be a lot of wasted time.

Is anyone aware of a different tail rotor system -- that would be everything associated with the tail case, shaft, hub, grips and blades that would fit on the end of the boom in place of the Kyosho stuff? At this point I'd be willing to swap out EVERYTHING on the rear end of the boom for a brand X assembly if I knew it had a chance of working. I guess the two limiting factors would be the belt pitch, and the tail boom diameter.

I've promised a true, no-holds-barred review of the EP400 here, and you're all getting the good, the bad, and the ugly here. Lately, more bad than good, and that's discouraging.

Dave
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01-15-2006 09:33 PM  13 years ago
ozace

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melbourne, australia

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Dave i will have a look at the tail s on some of mine to see if anything is usable. I know my Cal tail runs very smooth at all rpm so i would only be looking for the tail pitch mech/tail grip etc.

I will check the eolo and stingers to see if the tail output shaft is a match
we can never have too many, can we ?
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01-18-2006 03:18 AM  13 years ago
dkshema

rrMaster

Cedar Rapids, IA

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Update -- Chris at RC Heliworks is DA MAN!!!

The EH64 tail rotor shaft from the Concept SR-K arrived in the mail today. Chris offered it up, free of charge, to see if this fixes the tail rotor vibration troubles I've been having.

I put the new shaft in, fired up the heli, voila -- once again, smooth as silk.

I'm now back up to a 32-tooth pinion, the JGF 450TH motor, and NO SHAKES !!! Stupendous.

Smiles once again. I now know the reason for the "hot and cold" EP400!

Now, what was wrong with the old shaft? While changing out the old part for the new, I simply put the old TR shaft in the tail case (without the belt attached, and turned it). The original TR shaft was bent. Slightly, almost imperceptibly, but bent just the same. Now, back up a few posts. I had been having vibration trouble. I finally added some tape to the TR blade (pictures posted) and the shakes went away. All seemed good. Then, I removed the TR assembly to check how well balanced it was after adding that tape. I put the TR back on, and no matter what I did, the vibes NEVER got better. In fact, they got worse, and after nearly two days of screwing with it, I got nowhere.

As it turns out, the TR shaft was bent before I put the tape on. The bend was in the right location and small enough, that the tape was enough to damp out the bad shakes. There was still a bit, but the heli was flyable. Now, I removed the TR assembly to check the balance, took some pics, and put the assembly back on. But -- I couldn't get it in the same position that it was before I removed it. The position that it ended up in, was such that it would be nearly impossible to get the right combination of weight in the right place to counteract the off-center shaft. So, I ended up chasing my tail, only making matters worse, and getting really P.O.'ed at this little heli.

Somewhere along the way, I tried a cut-off section of brass flybar weight (same diameter, made of brass) in place of the original shaft. I don't know why, but I still had shakes. That's when I stated that the new shaft from Chris probably wouldn't help. I was wrong! I re-installed that shaft tonight as a double-check. It too, spins at full RPM, smooth as silk. I can't explain what happened with this test the other day. I guess all experiments can fail from time-to-time.

OK, so the horrible shakes that have plagued my EP400 were due to a bent tail rotor shaft. I rolled the shaft on the "gold standard" glass table. It appears that just putting the shaft in the tail case and spinning it works better! I verified the bend on the glass table again tonight, after the spin test...Only tonight, I did it VERY slowly, and VERY carefully. That's when the bend showed up on the table. The other day, I did not do this carefully, and the shaft looked straight. Lesson learned, GO SLOW when checking things.

The cause of the bend? Look at the pictures of the tail rotor blades. Their tips are scuffed. The stance of the EP400 on its skids places the vertical fin square on the ground. The TR blades have little ground clearance by design. The vertical fin doesn't do a very good job of protecting the TR. It's easy to bump the TR blades on the ground without noticing it, you just see some scuff marks later. Apparently, one or more of those bumps, bent the shaft. The shaft is SOFT, and EASILY bent. The TR blades are not well protected. This combination leads to easily bent shafts, and nasty, nasty vibrations.

Others have experienced this problem, some have lived with it, others have replaced the shaft with the harder EH64 from the Concept.

Now that I know the cause of the vibes, the cure for the vibes, and the reasons I missed the obvious clues, my EP is flying, and flying well. At least hovering VERY smoothly at this point. Maybe now I can get on with the flight testing, instead of pulling out my hair.

The long term cure? This goes back to my original wish list of things that the Kyosho folk need to address:
5. The skid struts could be modified to distribute the weight of the heli over more of the skid tube instead of having most of the weight on the rear tip of the skid tube. The weight distribution as it is, is the reason for having the vertical fin on the TR transmission touch the ground when at rest. Fix the weight distribution on the skids, and then make some longer cross struts to keep the TR out of the turf...

...The second most critical item would be fixing the weight distribution on the skids. This would require a redesign, and some new tooling.
Funny how earlier posts lead to later findings.

Maybe that item needs to be moved to priority ONE on the wish list.

OK -- now, FIRST PRIORITY:

Thank you, CHRIS and RC Heliworks. You're Number one on my vendor list.

Dwight -- Thanks for the advice and the tape trick.

Ozace -- Thanks for the offer to look for alternate parts for the TR stuff.

The rest -- thanks for putting up with this thread to this point. It should only get better from here!

-----

I looked over on the Kyosho Japan website last night, there is a list of EP 400 parts -- including OPTION parts. The one that caught my eye is the CA2100, Ti64 tail output shaft. A TITANIUM shaft to replace the soft one that is standard in the kit. I wonder when they will hit the streets here in the US?

Dave
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01-18-2006 03:51 AM  13 years ago
HELIWIZARD

rrApprentice

ardsley, new york

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hey dave
glad everything is going good with your heli now. i posted alittle over a month ago about the issue of the tailblades hitting the ground. a way to beat that is curve a rod or use a spare tail fin and raise the fin up about a 1/4 inch. yound have that problem hitting again

rick
also those ti parts have been on the options list for about a month.
cant wait till they make it over here.
ADDICTED TO HELIS ~ too much FUN
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01-18-2006 04:04 AM  13 years ago
dkshema

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Cedar Rapids, IA

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I replaced stock TR pusrod control link at the servo arm with a bit of leftovers from my T-Rex stuff...a short pushrod, small piece of brass tubing, some solder, a ball link, and a ball. Less stress on the servo arm this way.

Dave
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01-18-2006 04:33 AM  13 years ago
ozace

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melbourne, australia

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Progress,(fianlly) keep up the good work Davewe can never have too many, can we ?
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01-20-2006 02:19 AM  13 years ago
dkshema

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Cedar Rapids, IA

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A little bit of hovering in the driveway after work, and just before the sun disappeared in the West....smooth, fun to fly, feels like my bigger ships.

DPR plot:

Much different than the one I posted awhile ago. The EP400, a JGF450TH, 32-tooth pinion, and a tired Kokam 2000 mah pack.

The big spikes near the middle are me jumping on throttle to ascend from about a foot off the ground to about 25 feet, then back down. The rest of the flight consisted of hovering, and flying forward (about 45 feet away, then backward, stopping beside me. Except for the sudden throttle changes to gain altitude, and come back down, the voltage, current, and power curves are essentially flat. The battery pack was barely warm. I also got about 6 and a half minutes of flying out of the battery, as oppposed to the 5 and a half minutes on the previous plot. It appears when comparing this plot to my earlier one, the drivetrain is much happier without the TR shaking like crazy.

Average running current 9.3 amps, way way down. Average power about 92 watts. At this rate, the 450TH won't eat up the battery pack as I had heard it would. Could be a very good motor combo.

Now all it takes is some decent weather, some spare time, and a trip to the flying site to see how it flies.

Dave
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01-20-2006 06:09 PM  13 years ago
Dr.Ben

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Richmond, VA, USA

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Dave,

You'll be pleased in any case, but the current demands of that motor go up quite a bit when you start leaning on it hard in flight. My batt's were pretty much cool doing the same stuff you were. Reasonable 3D with the same model typically yields post flight temps in the low 100's with ambient temps a bit below 60 degrees. You ought to get a solid 8+ minute flight and replace about 1650 ma's into the pack upon recharging.

Ben Minor
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01-23-2006 04:30 AM  13 years ago
dkshema

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Cedar Rapids, IA

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With my Kokam pack and the 450TH, I'm getting about 6 minutes before the voltage begins to drop off, and only stuffing about 1350 mah back into the pack. It doesn't look good for the home team.

Out of curiosity, and having recently freed up my JGF 400DH, I installed that in the EP400 this evening, and put a 22-tooth pinion on it. The JGF website says the motor is rated at 4000 to 4400 KV. My DPR plot shows the battery voltage during the first flight to be just about 10 volts for the duration. Assuming a 4000KV motor, and 85% efficiency, this would put the head speed at about 2100 rpm. Assuming the 400DH is a hot one and puts out the 4400KV (and again 85% efficiency), the head speed would be about 2340 RPM.

I took the chopper out on the front drive, and hovered one pack in the dim glow of the yard and porch light. From what I can tell, the 400DH is quite a capable motor in the EP400.

What's killing me right now is that the Iowa weather sucks...and it hasn't been friendly to getting out and actually flying the helicopter, other than hovering and some forward/backward, sideways stuff in the street in front of my house.

I really need to get out and get some real flights with the 430L, the 450TH and the 400DH to see how the heli and the motors actually perform.

With the new EH64 tail rotor shaft, the EP400 is very very smooth and handles like a dream.

-----

Does anyone out there have a decent stateside source for 2000-2100 mah 3S LiPo batteries capable of greater than 15C discharge rates? It looks like Vinnie at Just Go Fly is having some trouble getting his new batts into the shop.

Dave
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01-23-2006 03:56 PM  13 years ago
Caliber1

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Fort Worth, TX

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Does anyone out there have a decent stateside source for 2000-2100 mah 3S LiPo batteries capable of greater than 15C discharge rates? It looks like Vinnie at Just Go Fly is having some trouble getting his new batts into the shop.
Try this site. I'm using a Dualsky 2200 mAh 3S battery rated at 12C continuous, up to 20C burst. It also has a balancing connector wired on the battery in addition to regular output wires. It goes for $64 and change at LHS here in Fort Worth, TX.

http://www.dualsky.com/main.asp?mainset=24
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01-25-2006 02:20 PM  13 years ago
RCHeliWorks

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RCHeliWorks

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i replaced all mine on the head assembly with ones from the caliber 30 but have not tried the tail yet

chris
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