Please help me setup my EP Concept - RC Groups
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Dec 06, 2003, 05:46 AM
A-4 nut!!
skyhawk's Avatar

Please help me setup my EP Concept

I have a few questions about my EP Concept. I tried flying it today.

1) How do you guys secure your battery? Mine popped off during a hard bounce. Some velcrow and those useless batt clips just don't do the job.

2)I got the ship to hover at about 3/4 throttle about 4 feet off the ground. I then landed and took the foamie blades off , replacing them with JRC washout blades. The heli wouldn't even lift off at full throttle - why? Do I need to re-pitch the blades? I double checked that they were on the right way.

3)I set up everything the way the book said to but my tail rotor needed to be adjusted so that at neutral, the pitch slider was almost fully outboard - leaving very little movement outboard. Why is this? Is this normal? I am using the wire pushrod and it is secure. It also moves freely. T/R control is great but why is this offset?

stock foamie blades
GY240 gyro
Stock s-power 14t motor with 15T pinion
8 cell HRSC 2600 battery
2 JR 507 servos and 2 JR 331 servos
Lite machines fusion 35 esc
JR X347 radio

pitch curve 0 25 50 75 100
throttle curve 0 50 100 100 100

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Dec 06, 2003, 07:14 AM
Registered User
1.) The instructions call for a rubber band to help the battery holders hold the battery. I used an "O" ring instead of a rubber band. A little velcro will still help keep the battery from sliding. I am not sure why kyosho would make batt holders like these that are not spring steel.

2.) Make sure you track the blades. With the blades spinning at speed, looking from the side, you should see one plane. I know I tried flying once without the blades tracked and it would not lift off. After getting them tracked properly it had plenty of power. Another thing to try, after confirming the blades are properly tracked, is a pinion with a higher tooth count.

Just out of curiousity are you able to get the foam blades tracking?

3.) not sure here but fix number 2 first and see if that helps.

Let us know how it goes. Joe
Last edited by JoeR; Dec 06, 2003 at 07:19 AM.
Dec 06, 2003, 09:00 AM
A man with too many toys
3) This is a sign that the head speed it to low. My throttle curve is 0-85-90-95, which should give better performance with the foam blades.

The Concept is best if you keep the weight down, small servos, Rx, gyro, and ESC. I use the smaller CP1700 8-cell battery pack. Less flight time but much better performance.

Since you are already running a throttle curve of 0-50-100-100-100 you definitely need a larger pinion or better motor.

As for blades with washout the washout decreases the overall blade pitch so you either need more head speed (hotter motor or larger pinion) or more blade pitch. The concept does fly better with more head speed.
Last edited by RC Man; Dec 06, 2003 at 09:03 AM.
Dec 06, 2003, 03:36 PM
A-4 nut!!
skyhawk's Avatar
Thanx for the answers guys. The ship came stock with the 15T pinion, I have an 18T pinion. Is that too large or should I get the 16 T?
Dec 06, 2003, 03:42 PM
Registered User
Since you have the 18 give it a try. Just don't get the blades spinning too fast as they are wood. Maybe 1700,1800 max?
Dec 06, 2003, 03:43 PM
A man with too many toys
Do a test flight with the JRC washout blades and the 18t pinion gear. Hover for about a minute then land and check the motor temperature.
Dec 06, 2003, 03:53 PM
Registered User
thazy2's Avatar


the foamies are NOT that bad. They are cheap to learn on! However, SOME sets or blade are just BADfrom the factory. If you order, order several set. If you have tracking issues, try adjusting the rods then switching out the blades. Out of the 10 or so set I have had TWO blades were defective. Just send them to Great planes/ Hobbie services and they will give you a new set, as long as you have your receipt.

two, the stock motor is awful! At my altitude of 5000 ft, I can NOT get the ship off the ground on 7 cells. Eight cells works but lifeless. Weight to power ratio and air density (colorado) needs to be consider.

1. Switch your battery to 1700scr or 1950faup 7 or 8 cells, a fraction of the weight w/ the same amount of power, less some duration, on the setup that you have now.

2. Brushless w/ 3300Kv to 4400Kv. Lots more expensive, longer flight time and you dont have to deal w/ comm dust and brushes. And you can use your existing packs.

3. Place a BIG tornado fan under your heli and crank it to HIGH!

4. Shoe goo some velco straps on to the bottom chasi on top the front of the pack and on top at the back of the pack for some serious solid support. Kinda wrapping the battery w/ small strips of velcro.

5. Change your servo to precision MINI servo. Get some of that weight off.

Remember if you lighten the ship, it will be less stable during light wind condition. For good solid hovering and trainning, use 8 GP 3300 cells, brushless, and full size servos.

"3)I set up everything the way the book said to but my tail rotor needed to be adjusted so that at neutral, the pitch slider was almost fully outboard - leaving very little movement outboard. Why is this? Is this normal?"

if i understand you correctly, you dont really need much pitch if you want the tail to move clockwise. However, you do need lots of pitch to move the tail counter clockwise in ordor to couter the rotation energy of the main blades going clockwise. It should rought pictch 30% on one side and 80-100 percent on the other.

Hope that helps.................Jason
Dec 06, 2003, 09:20 PM
A-4 nut!!
skyhawk's Avatar
With respect to the foam blades, I balanced them making sure the c of g of each blade is in the same spot and then make sure each balde itself weighs the same. They have stayed in track very well.

I re adjusted my pitch and throttle curves, and got a hold of a real pitch gauge. It will now hover really good. One thing baffles me though. I need almost full throttle for about 30 secs or so and it is just light on the skids, then it will break ground. Once it does that it climbs and climbs (not very fast mind you). I bring the throttle down a little - nothing. A little more it stops, a little more it starts down and then I can hover about 3.5 feet off the ground at about half throttle. Why is there such a delay? All linkages work well.

I think I am bogging the motor a little with too much pitch, but it wouln't take off at the specs in the manual. Althogh not efficiant, I guess as long as the motor and ESC arn't getting hot, this would be OK. What do you think?

PS I want to try other pinions and motors but can't tac the rotor and I'm pariniod about going to fast on the headspeed.
Dec 06, 2003, 10:12 PM
Registered User
thazy2's Avatar
Your oem motor is most likely fitted w/ bushings. Try one of the Kyosho Atomic force family w/ 13 turn. Those come standard w/ ball bearing. That may give you a little more effiency and power. The motor is only $20. You can also adjust timing on these motor for rpm.

I dont thing you need to worry about having too much headspeed as long as you utilize the oem pinion and one or two turns less motors. Even if your capable of hiting 2000 plus headspeed, you will not be at that level for hovering or floating back a fourth. Otherwise, the ship will climb to high to control or hover. Having excess power doesnt mean your going to use it. Its nice to just have it just in case you ever need it, like falling very fast and you need excess power for a few seconds to recover. Trust me, it will happen!
You can also limit power execution w/ the throttle curve.

Having too much power is a good thing...................Jason.
Dec 06, 2003, 10:19 PM
Registered User
But thazy2/Jason he is flying a collective pitch machine. So he will set his throttle up on his transmitter and won't be able selectively use the additional power to get out of trouble, right?

Also, I am not sure if brushed setups are like brushless where brushless are more efficient (longer run time, less heat, etc) at 90%+ throttle setting. In otherwords having too much power on reserve would be a bad thing.

Skyhawk, did you try the JRC blades again? Your last post did not specifically state this.
Last edited by JoeR; Dec 06, 2003 at 10:24 PM.
Dec 06, 2003, 10:51 PM
misskimo's Avatar
hey , one thing , is the motor new ? and another thing , did you set anyclearence between the pinion and the secondary gear , if not use a thin peice of paper , like newspaper , writing paper makes it a tad noise , the 16t will help alot , I flew over 100 flights on my stock motor without changing brushes or anything with just 7 cells

Dec 06, 2003, 11:58 PM
Registered User
thazy2's Avatar
JoeR, I agree w/ what your saying. But from my experience (what little there are of it and still learning) have some reserve capacity is more desireable than insufficient power. I not implying to run your motor at half capacity all the time. Yep, that would be pretty much a waste and very inefficient. What i ment is set the throttle at 0-30-50-70-85. Therefore, you would not have an over power situation. At least, that is what I did on my EP and Corona w/ Hacker c40 12T. They seem to work good on eight cells and 7 cells. On eight cells, I just tone the throttle to 0-30-50-60-75. Its probably not the norm or 100% effecient but it works for me. Again, im still leaning myself. Feel free to shoot anything down. Constructive criticism is always welcome. Maybe I will learn something new also.
Dec 07, 2003, 05:50 AM
A-4 nut!!
skyhawk's Avatar
No I did not try the jrc blades again. I wanted to try and get things figured out one at a time, And it is flying on the foamies. It took a whila to get used to the more sluggish response of the cyclic. But looking at it more closly - it's the way the head is designed.

I'd really like to know what is up with the SLOOOOW pitch response??!?
Dec 07, 2003, 07:52 AM
Registered User
Knowing that you have the foam blades on...Besides the hinging/flexing nature of the head design, the slow collective (pitch) response is a result of the flexible foam blades. When you increase your pitch from 0 do you see the tips of the blades rise quite a bit before the helicopter? Wood blades are stiffer and weighted at the tips so they will maintain a flatter disk and react much faster for better collective response.
Dec 07, 2003, 02:50 PM
Registered User

you need more pitch

I don't know if you can read Japanese or not, but in the JRC Washout blades from Asami RC in Tokyo, there is a piece of paper included with the blades. It indicates that more pitch is needed for the washout blades. My instruction sheet was printed on pink paper and it says to add 6 degrees more pitch !!! as a starting point. Then if the engine bogs, decrease the pitch in 0.5 degree increments.I don't have a pitch gauges, but I do remember having to turn the pitch ball links several turns when swapping blades.
I still have the instruction sheet, so if you have any more questions please ask.