RunRyder RC Helicopter Topic - EP 400 Build Thread

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e-New & Emerging Electrics > EP 400 Build Thread

ozace
Key Veteran
Location: melbourne, australia

Nice pics Dave.
I have a Japanese edition Cal and the canopy came white, painted from the inside. I used the extra battery mounts in the box for the battery mount. The "u"shaped ones didnt help but the 2 piece side brackets can be mounted to sit either side of the pack and i then use a rubber band to hold the pack in place. Because the motor i use and the lipos are so mucher lighter than stock the pack need to be pretty far forwards. I had to trim a little of the bottom lip of the canopy to allow the pack to slide forwards enough.

we can never have too many, can we ?

12-19-2005 Over year old.

Dwight
Senior Heliman
Location: West Chicago, IL

Dave,

The stock mount will accomodate any batteries. They have designed the mount with several holes in the frames to use either square packs or long packs. The mounts are slotted so you can tighten them up accordingly.

Dwight

12-19-2005 Over year old.

Dwight
Senior Heliman
Location: West Chicago, IL

Why do you say they won't fit? Is it that you need to use a little foam to fit the front mount? Can you post a picture so I can understand the problem?

Dwight

12-19-2005 Over year old.

dkshema
rrMaster
Location: Cedar Rapids, IA

I haven't gotten to the battery mount problem yet. First impressions were that this was going to be tricky with other than the nicad sticks. First impressions can be wrong.

I'm up to my eyeballs right now getting paint on the canopy. All went well this morning till I shot the transparent blue for the winscreen. ^&##%# paint ran and sagged. Had to clean the entire upper half of the canopy off with mineral spirits and remask it, to try again.

Dave

12-19-2005 Over year old.

dkshema
rrMaster
Location: Cedar Rapids, IA

I've posted a few more pictures tonight, the finished heli - a couple of views, a shot of a Kokam 2000 mah LiPo installed, and a shot of the little heli from above.

The canopy paint job turned out to be a "10 footer" -- looks good at a distance, but don't get too close. I used Testors spray enamel -- yellow and transparent blue. My shots at the yellow worked out very well. But, when I removed the masking and shot the transparent blue for the windshield, I put a bit much on, and the junk ran and sagged. I cleaned the entire canopy off using turpentine and mineral spirits, then repainted. There's something about small cans of spray paint, an unheated 3rd car garage, and 11 degree temps that just don't mix. On the other hand, had I been a bit more patient and attentive the first time around, the result would have been much cleaner and better executed.

Tonight I installed the "3D upgrades". This consisted of adding a bolt through the head, that goes through the spindle shaft, locking it in place so that it can't move back and forth (left/right) in the head, and also acts as a fixed point around which the spindle will will rotate as it moves up and down in the hub, being damped by the rubber O-ring dampers.

The second 3D upgrade consists of removing the MR grips, removing an aluminum bushing, installing an extra O-Ring on each end of the spindle shaft, then replacing those two bushings with two that are shorter (to accomodate the thickness of the extra O-ring.

I thought that mounting a battery pack would be tricky, since the heli doesn't seem to be set up to fly other than the standard nicad stick pack. I was wrong. The picture of the Kokam pack installed in the EP 400 in my gallery shows that the Kokam pack drops right in. I think my TP Gen II 2100 pack will also fit with no hassle.

With the Kokam pack installed, the heli as set up balances on the MR shaft, not tail heavy or nose heavy. I suspect that with the TP Gen II 2100 pack, it will be a bit tail heavy.

A word to Kyosho here. The one-piece skids/cross struts landing gear is OK -- BUT -- the cross struts are probably raked forward at too great an angle. The stock design may make the chopper look dashing and eager to go, but when the chopper sits on its skids, it actually puts most of its weight on the tails of the skids, behind the rear strut. I'd believe that were the struts not raked forward as much as they are, the bulk of the weight of the chopper would rest on the skids at or just forward of the rear strut, not on the tails of the skids alone.

Still waiting for a chance to get the bird up in the air. I added a ferrite toroid on the ESC to RX cable this evening, as I've found this necessary with the Castle Creations controllers. No trouble adding or mounting it using double sided foam mouting tape.

The weather is supposed to moderate here over the next few days, giving me a chance to maybe take it out on the front driveway and get some hovering an maybe a little bit of flying in. Last minute Christmas shopping, along with helping someone move to town this past week, and the frosty weather have all conspired to keep me from finishing and flying the EP 400.

I still need to track down a Deans whip (or other suitable) antenna for this chopper, but the full-length stock antenna on the Electron 6 should suffice for the first couple of test hops.

I can't wait to take this little heli out and give it a go.

More to come.

Dave

12-21-2005 Over year old.

Trondhjem
Heliman
Location: Sokna NORWAY

Hello.
I use a 2500 mha batt pack in mine.
And i have no trouble putting on the canopy.
Look on mine pic.
And on http://www.ringerikemfk.com/index.p...bnails&album=13
I use a 26 64p 3.17 bore pinions one mine.
Now i have to fine tune the gyro and get soft start on to the ESC.
Odd Arne

12-21-2005 Over year old.

Dwight
Senior Heliman
Location: West Chicago, IL

I learned today that Kyosho America has pinions for the Caliber 400 that are the metric .4 module. They have the stock 20 that is 2.3mm and then from 25 to 50 teeth with a 3.18mm/1/8inch bore.

Dwight

12-21-2005 Over year old.

dkshema
rrMaster
Location: Cedar Rapids, IA

I got about five minutes worth of flying on the EP 400 this morning. It was a bit cold outside, and I had to try to hover between the huge snow piles on the edges of my driveway and street.

I still have to check the balance (and maybe correct) the head and TR stuff. I just sneaked out and flew without going through all those details right now.

The first thing I had to do was tame the gain on my GY401. I think it's down around 15% now, any higher I had lots of TR wag. I think the wag problem is going to be a combination of servo arm length, gain, and delay settings. This might take a while for the right combination to be worked out.

I tried setting up the MR pitch on the bench using a pitch gauge, but found this to be difficult, as there is a lot of play in the collective system. Kyosho is definitely going to have to do something to fix this problem and tighten up the collective system. I've read one other post where the fellow stated he had difficulty setting the pitch due to all the play in the collective. I believe this truly needs to be much tighter.

The heli in a hover was quite wobbly -- it reminded me of the wobble my Caliber 30's exhibit when you get the head speed too low. I started adjusting my throttle and pitch curves to increase the head speed. Unfortunately I ran out of battery juice just as I was getting the hang of things.

The Align 430/3550 Kv motor seems to do quite well in the EP, and I'm using a 20-tooth pinion (same number of teeth the stock motor ships with th EP 400).

I'll need to get more time on the chopper, and get it somewhere besides my front yard before I can get a good feel for how it's going to perform. Slowly, but surely, I'm getting the EP together and flying.

Dave

12-21-2005 Over year old.

dkshema
rrMaster
Location: Cedar Rapids, IA

A fresh charge on the battery, a bit more head speed by goosing up the throttle curve a bit, and the little EP settled right down. No more wobblin' goblin. Very smooth in hovering now.

The heli is responsive, but not as twitchy as the T-Rexes I've flown. So far I've found no reason to dial in expo on the cyclics at all, this could be due to the heli design, or possibly due to the flybar weights. Don't know at this point.

Don't ask me what the head speed is, I don't have a tach, and couldn't tach it myself, anyway. I'm pretty sure I'm up in the mid 2000's, though -- maybe 2300 -2400. Comparable to what my T-Rexes are turning.

I need to trim out the tail rotor, to get a bit more right rudder, but other than that, the heli hovers very well right off the board.

I didn't fly very long, at 20 degrees F, the thumbs get stiff in a hurry. I need to order a Deans or other whip antenna, that 39 inch long wire is an accident waiting to happen.

More to come as I get more time in the air and more tweaking.

One thing is certain, an earlier post on a different thread here on RR, stating that the EP 400 flies like crap and won't get off the ground no matter what -- is just plain wrong. It's quite obvious that the comment was made by someone who has no knowledge of what it takes to get a small electric heli airborne. The EP at this point appears to have some potential.

Dave

12-21-2005 Over year old.

Dwight
Senior Heliman
Location: West Chicago, IL

Dave,

I think the 20 tooth pinion is not nearly enough to get a good head speed that will give you good performance. I was running an 18 tooth with a 5000kv motor and was turning about 2600.

Dwight

12-22-2005 Over year old.

dkshema
rrMaster
Location: Cedar Rapids, IA

To save some you the trouble of doing some math, here's a table of overall reduction ratios for the EP 400, for 15 tooth up to 34 tooth pinions:

15T = 23.4:1
16T = 21.98:1
17T = 20.69:1
18T = 19.54:1
19T = 18.51:1
20T = 17.58:1
21T = 16.75:1
22T = 15.98:1
23T = 15.29:1
24T = 14.65:1
25T = 14.07:1
26T = 13.53:1
27T = 13.03:1
28T = 12.56:1
29T = 12.13:1
30T = 11.73:1
31T = 11.35:1
32T = 10.99:1
33T = 10.66:1
34T = 10.35:1

Here is where the numbers come from:

The motor pinion meshes with a 67 tooth gear. This, in turn, drives a 20-tooth pinion that meshes with the main rotor drive gear which has 105 teeth. The 105 tooth/20T combination is a 5.25:1 ratio.

To compute the overall reduction from the motor to the main rotor:

Divide 67 by the number of teeth on your pinion. Multiply that result by 5.25 to get the total reduction ratio number.

Dave

12-22-2005 Over year old.

ozace
Key Veteran
Location: melbourne, australia

Dave you put way too much effort into that

we can never have too many, can we ?

12-22-2005 Over year old.

dkshema
rrMaster
Location: Cedar Rapids, IA

Dwight,

I guess that means I'd need either a higher KV motor as you have, or a lower KV motor that wouldn't burn up with a larger pinion!

I'll give the Align 430L a shot, maybe it can handle an additional tooth without going up in smoke.

If a higher KV motor is necessary to get the EP 400 really flying, maybe this is going to turn out to be a machine that needs a 4S setup, instead of the more economical 3S setup. Gee, I hope not, the extra cost associated with a charger capable of 4S battery charging, a separate BEC, and the battery itself would scare a lot of potential buyers away from the EP 400.

Seems that if you look at the EP 400 manual, the motor that is listed as the optional brushless upgrade is only a 2750 KV motor. That's a far cry from your 5000 KV, and my 3550 KV 430L. How does Kyosho get that 2750 KV motor to turn the head fast enough?

I still need to find out if that collar on the MR hub that limits the flybar travel is needed, or if it's there to tame down the EP for novice flyers.

----------------

As far as Kyosho goes, there are some things that at least to me (and others) need immediate attention in this helicopter kit. Those being:

1. MR blades should have root reinforcements. These would increase the safety margin with regard to rotor RPM and would also make for a better fit of the blades in the grips.

2. The Z-bends in the head need to go and ball links need to replace them.

3. The excessive play in the collective pitch stuff needs to be eliminated. Getting rid of the Z-bends will help, a better washout block will help fix this as well.

4. Some of the ball links need to fit a LITTLE tighter (swashplate). Not much tighter, just a hair!

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.

6. The servo mounts for the TR and the Collective servo should accomodate servos such as the Hitec HS56, a popular choice for micro helis.

7. Sell the kit without the brushed motor, drop the cost a few $$$ as a result.

So far, nothing in the list above is a show stopper. The most critical item to fix would be the slop in the collective pitch control. Maybe this requires new tooling, a new design, but now is the time to do this, early in the introductory cycle. This solution would probably take care of three items on my list -- slightly loose ball links, the washout base, and the Z-bends.

The second most critical item would be fixing the weight distribution on the skids. This would require a redesign, and some new tooling.

The third most critical item would be blade grip reinforcements. This isn't that big a hitter, sure there would be some tooling changes, but the finished product can simply be inserted into production and into the spares chain when available. The current stock of MR blades would simply be used up.

The easiest thing to do is to stop shipping the brushed motor in the kit. Keep the adapter plate, maybe make it a little more universal. Not installing the motor in the kit would save production costs as someone somewhere has to install the pinion on the motor, then install the motor in the chassis. Cut this cost out and use the revenue to fix the MR collective pitch system.

Dave

12-22-2005 Over year old.

ozace
Key Veteran
Location: melbourne, australia

Super wishful thinking there Dave. I hope someone listen to you.
I sent messages direct to Kyosho very early on about a few little things.
No reply though i know they recieved the mail. I wouldnt hold my breath waiting for the fixes. Shame really as i like the "feel" of the Cal but i dont think K are set up to move quickly like Align does.

we can never have too many, can we ?

12-22-2005 Over year old.

Dwight
Senior Heliman
Location: West Chicago, IL

Dave,

I wrote an Excel spreadsheet program that will give you the head speed on any kv motor based on 15 through 50 teeth. All you do is enter the motor kv and the program calcs the rest. I would attach this for anyone who wants it but I don't know if that can be done. If you have any interest I will send it through to anybody on private email.

As for the 3550kv motor being good enough...I am merely suggesting that a 20 tooth pinion is not enough. The motor is probably fine but the gear ratio will only give you a max RPM of 2241 unloaded. Based on what Shaun at Hacker told me you need to calculate approximately 85 percent of the unloaded speed to get true/useable RPM. This would put your setup at around 1900 loaded. This is not enough for any kind of good 3D. You need more like a 24 to tooth to get the RPM around 2700 unloaded so under any load you will be holding about 2300. The reason I tried the 5000kv motor is that Aon sent Kyosho 2 of them to try in a car and I wanted to give it a try. I will say that it is awsome with that much power but not necessary. The 2750kv motor Kyosho uses has a recommended pinion of 31 to 33. With the 33 tooth, which is what Kyosho sent me to use for demos, gives an unloaded headspeed of 2850 and loaded of about 2450. This flew very well but the motor could not maintain RPM during constant 3D. This is what motivated me to try some of the more powerful engines.

Just like the T-Rex you want to get the head speed up for crisp 3D. The machine is not twitchy at all when you spin the head up either.

I removed the collar on the yoke and flew it. There did not appear to be any difference in the control rates. Like you the weather in Chicago is cold so I have not had the chance to do extended testing to be positive but it looks like there is no difference. This reminds me of a thread long ago about flybar travel and in many cases the flybar never moves as far as you think. To see this you need to use a high speed video camera that can stop frame to see this.

Dwight

12-22-2005 Over year old.

dkshema
rrMaster
Location: Cedar Rapids, IA

Dwight,

Is there ANY chance of getting Kyosho to move off the dime and address the slop in the head? Sometime in our lifetime?

This one issue is probably the most serious drawback I've found in the EP. The early T-Rexes -- the 450X and 450 X-V2 were notorious for having sloppy MR control systems, but at least you could easily fix them with a shot of CA and some ingenuity. The T-Rex XL version effectively addressed ALL of the slop issues in the control system, and all of the corrections were done in plastic, no CNC machined parts were required. The fix included a number of additional ball bearings, but as the sales numbers for the T-Rex XL (and SE) indicate, people are willing to shell out for a quality control system.

I'd much rather have a tight control setup over a brushed motor that's going to end up being a paperweight.

-----

As for your Excel spreadsheet...if you can zip it up and email it to me, I can post it up on my gallery here on RR for all to have. PM me for my email address.

Dave

12-22-2005 Over year old.

Chem Geek
Senior Heliman
Location: Sarasota, FL

Has anybody flown this thing on the stocked brushed motor with 10x1100 or whatever it calls for? Does it even move? I just want something cheap and fun, and this brushless/lithium required mentality for the little ones gets me down.

12-22-2005 Over year old.

dkshema
rrMaster
Location: Cedar Rapids, IA

Physics

...if I had the extra cash burning a hole in my pocket, I'd spring for a brushed controller and a stack of nicads or NiMh batteries and give it a try. I guess that question does need to be answered.

But, knowing that brushless and LiPos are where the real action is, I chose to buy a Phoenix 35 controller and use the LiPos I already have (and maybe add a couple extra packs early next year).

Dave

12-22-2005 Over year old.

Trondhjem
Heliman
Location: Sokna NORWAY

Hei.
Go for bruch less and have fun.
Stock engine is crap