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Scorpion Power GLOBAL 3D
HelicopterScale Model RC Helicopters › Roban 700 2 Blade models Head Speeds
TailKiller

Senior Heliman

Panama City, FL

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Those of you who are flying 2 blade Roban models like the Bell 222 and AH-1 and so on, tell me what HS that you have settled on. At 1350 mine floats around a little more than I would like it to. I'm flying an AS350 on 2 blades, I couldn't get the 3 blade to handle right. So I am not as streamline as other 2 blade models. It's more like a flying school bus so aerodynamics are a little worst.
Also does anyone know the recommended max HS for these models, I've not seen it anywhere. Thanks.

,Dennis
http://pcrcheliclub.com/
700 Astar Super Scale T-600 Bell 206 Trex 600 Naza H DX8

04-01-2017 12:34 AM
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ssmith512

Key Veteran

Indianapolis, IN USA

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Head speed will go hand in hand with blade choice.

I run Spin asymmetrical 800mm blades on my Roban Cobra. Headspeed is governed at 1200rpm. Flies AWESOME.

Steve

04-01-2017 03:55 PM
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TailKiller

Senior Heliman

Panama City, FL

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I'm using Spin Blades 700mm symmetrical's for efficiency. I like the lift power of the asym's but not the drag.

,Dennis
http://pcrcheliclub.com/
700 Astar Super Scale T-600 Bell 206 Trex 600 Naza H DX8

04-01-2017 05:39 PM
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Keygrigger

Veteran

Mississauga, Ont. Canada

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Hi:

I will have my MD7/8 with me at the Scale event coming up in Panama City and hope to have the ship converted to 800 before I leave. I will be running it at 800 to 1100rpm with up to 10 pounds of lead weight attached. It will be a 25 pound pod and boom when done as it is 15 pounds right now RTF. I am running Rotor Tech 710's and will be using Rotor Tech 810's once finished. I can't slow these blades down right now with a full pitch climb-out but when you have a 7125 watt motor, it's hard to stall it, lol. See you soon.

Don

04-01-2017 08:00 PM
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TailKiller

Senior Heliman

Panama City, FL

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I got it flying better today at 1350 rpm. What I am asking is input from those with the 700 roban 2 blade mechs with the 13.8:1 gear ratio and the 22 tooth stock kit motor pulley. I'm using a 4525 520 kv motor. I don't want to lower the HS cause I'm running 65% on the esc and the esc temps are 170 degrees at the end of a 5 minute run even with a fan. I have a 20 tooth pulley but that means tearing it apart again. Thanks.

,Dennis
http://pcrcheliclub.com/
700 Astar Super Scale T-600 Bell 206 Trex 600 Naza H DX8

04-02-2017 12:39 AM
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ssmith512

Key Veteran

Indianapolis, IN USA

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What I am asking is input from those with the 700 roban 2 blade mechs with the 13.8:1 gear ratio and the 22 tooth stock kit motor pulley.
Exactly what I am using, the box stock Roban mechanics. 450Kv motor, Castle Talon 120 esc with fan running about 92%, for a governed headspeed of 1200rpm.
I'm using a 4525 520 kv motor. I don't want to lower the HS cause I'm running 65% (1350rpm)
That doesnt make any sense. Even at unloaded, full battery voltage (which wont happen during flight)......4.2*12*520 = 26208/13.8 = 1899 MAX headspeed. 65% of that would be 1234 headspeed.

At 65% ESC under normal load during flight, I calculate a headspeed of approximately 1116......3.8*12*520=23712/13.8 = 1718*.65 = 1116.

Steve

04-02-2017 01:08 AM
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TailKiller

Senior Heliman

Panama City, FL

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Thanks Steve. It doesn't make sense to me either. All I know is what the CC logger shows me. And the CC set rpm % for 1350 is 90.2%.. I know it will actually run lower % than that at start of flight but not 65%. And yes I have the correct kv, poles and gear ratio entered. Exactly how much of a difference does it make between the 450 and 520 kv motor make?

,Dennis
http://pcrcheliclub.com/
700 Astar Super Scale T-600 Bell 206 Trex 600 Naza H DX8

04-02-2017 01:26 AM
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Keygrigger

Veteran

Mississauga, Ont. Canada

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Dennis, the 450kv motor, if used with your gear setup, would yield an output of 1205rpm at 92.5%. You most likely have the setup in the ESC correct but when you go to view it, sometimes it defaults to a previous setup used to view the info in Castle View. You should check that in the Edit pane, the gear ratio and pole count match your setup. Hope this helps.

Don

04-02-2017 02:55 AM
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ssmith512

Key Veteran

Indianapolis, IN USA

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If you are using Castle SET RPM, then you should be running a 30% flat line curve for 1 headspeed, a 70% flat line curve for a second headspeed, and a 100% flat line curve for a third headspeed - like have having a normal, idle up 1, idle up 2 - for three different headpseeds.

Using your 520Kv motor, and the Castle Link software, I am coming up with a usable headspeed of anywhere between 1075 and 1425 while still keeping the ESC within its designed range.

Not real sure where your 65% is coming into play.
Exactly how much of a difference does it make between the 450 and 520 kv motor make
Only difference being usable headspeeds with the 450 (lower Kv) motor giving you lower headspeeds. I choose a 450kV motor because I knew I wanted my headspeed to be around 1100 to 1200. The Castle ESC works best around 90%, so the CastleLink software told me I needed a 450kV motor. I run SET RPM like you and my throttle curve is a flat line 70% for a governed headspeed of 1200. That puts the ESC right in the sweet spot of 92%.

Steve

04-02-2017 03:05 AM
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TailKiller

Senior Heliman

Panama City, FL

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I know the Talon's don't have logger graphs. You are right that it falls within the desired range. It's the actual flight data log thats show the esc power % during the flight. That's where the 65% comes from. I plan to fly tmr and I will post a log pic. I have already deleted todays logs.

,Dennis
http://pcrcheliclub.com/
700 Astar Super Scale T-600 Bell 206 Trex 600 Naza H DX8

04-02-2017 03:24 AM
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TailKiller

Senior Heliman

Panama City, FL

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Thanks guys.
Don, I checked the Edit, and the info was correct.
So I'll show you'll what the logs show. I flew two 5 minutes flights for each set of packs, 4 flights total, 2 sets of packs.

The first set does not have current and voltage showing.

In this set I changed to Medium Governor Gain for the first flight and then went back to High Governor Gain for the second flight. Note the last flight was the highest esc % of just below 73%.

I did notice for the first time that when powering up for the second flight of each set of packs that the esc counted only 11 cells. The packs are brand new.
So what do you'll think?

,Dennis
http://pcrcheliclub.com/
700 Astar Super Scale T-600 Bell 206 Trex 600 Naza H DX8

04-02-2017 09:39 PM
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TailKiller

Senior Heliman

Panama City, FL

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Sorry... the first set had the highest % out.

,Dennis
http://pcrcheliclub.com/
700 Astar Super Scale T-600 Bell 206 Trex 600 Naza H DX8

04-02-2017 09:41 PM
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Keygrigger

Veteran

Mississauga, Ont. Canada

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This is what I am seeing. You can go back to the lower gain setting as it seems to have no effect on the power consumed. High gains on the rpm change can slowly wear things out in the drive train line pins in main shafts as when there is a change in rpm, the faster it changes, the more power is applied to the gear train. As to governor gain, you most likely will never need more than default setting as increasing it can cause some very funny noises to come out of the motor when that gain is too high. There is very little variation in the rpm graph line but that could be the recording time you are using. If you record every ten seconds, then the graph will be somewhat smoother.

As to why the ESC shows 11 cells, that is easy. When you are flying two times per battery charge, the second time it goes out, you have already lowered the voltage overall and now the ESC sees the total voltage as that of an 11 cell pack rather than a 12s pack. This can bite you in the butt if you are not careful. Personally, I fly once per charge and no more.

Let's take the worst case scenario about using cell counting and what you are doing with two flights per charge. If you have set your cut-off voltage based on the cell count, what will happen is that it will average the voltage once an 11 cell pack gets down to 3.2v per cell but based on that count, the voltage would be 35.2v total, or based on the actual 12s pack, you would be under-voltage and bound for battery purgatory. If in doubt, charge after every flight.

The temperature change from the first flight to the second flight is the cool-down that the ESC has had between fights. The temperature overall is well within operating range and temps in the 150F are normal. When you fly in the fall and spring here, temps under 100F are very common. I had temps in the 160F range from my TOW Defender so yours is good. Hope this helps.

Don

04-03-2017 03:52 AM
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Andy01

Senior Heliman

Brisbane, Australia

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Dennis

Are you saying that it was 11s because you heard 11 beeps, or because of the voltage it displayed ?

I have been flying 2 flights on a pair of 6s packs for years with CC Ice 2 & Edge HV ESCs and never had a problem. It always shows the correct voltage at the start of the second flight.

I generally try to have pretty much everything including the governor gain on the "tamest" setting available - so gain on low, rate of change of speed on low, and spool up speed on 1. This helps to keep any sudden changes to a minimum and preserve gears.

I fly my Vario Long Ranger (2x 710mm blades) at 1350rpm, and it flies well at that. I get two 6 minute flights usually from a pair of Turnigy 5000mAh 6s.

Colin

Vario Long Ranger 700e
Seahawk 600
UH-1N 500
Baumann EC-145 800+ (coming soon )

04-03-2017 08:45 AM
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TailKiller

Senior Heliman

Panama City, FL

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Thank you Don, Colin and Steve
Don, Colin.. We have had a lot of post and emails over the last few years and I appreciate you sharing your knowledge with me.

About the 11 cell count on the second flight. It is a 11 count beep from the motor. But the voltage is correct. Don, your explanation of what could happen with lower voltage on flight 2 of the same packs, makes sense to me and I understand how and why it could bite me. I can't help but notice that you both have a different opinion about this.

I went back to High gov gain cause I could see and hear the rpm drop and tail slightly let go at times on Medium setting but I will play with that some more.

The one thing you didn't address is the low esc power out % for this gearing. I should have been near 90% at the end of the second flight and I am no where near it. I barely made it to 73% and although the esc temps are ok, they would be lower if the esc would open up and reach the stated % rate. Thanks
Dennis

,Dennis
http://pcrcheliclub.com/
700 Astar Super Scale T-600 Bell 206 Trex 600 Naza H DX8

04-03-2017 10:10 AM
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TailKiller

Senior Heliman

Panama City, FL

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Ok guy's
I spoke with a Castle Tech this morning and here is his explaination for why I am not seeing higher power out %'s on the graph. Now I have not noticed what he said would happen in my past flights where I have used all three idle postion but, I don't remember.

In a nut shell he say's that while flying in Normal at 30% flat that the esc will not reach full power out % range. That it needs to get a signal of Idle1 at 70% before the esc can begin to reach 100% power out %.

I'm currently at N=1350 I1=1400 I2=1450 and have flown in all three modes, so I should have seen higher power out % but I don't remember and I have no saved logs. So I will have to test this theory in the next few days.

,Dennis
http://pcrcheliclub.com/
700 Astar Super Scale T-600 Bell 206 Trex 600 Naza H DX8

04-03-2017 05:53 PM
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old nitroman

Senior Heliman

Naples florida

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I'm running my super scale 222 at 1350 to 1400 head speed any lower, I really start to lose the tail, I have 116 tail blades wish I had bigger tail blades.

E5s and E7se, Roban bell 222 800 superscale,450 bell 4 bladed head,gobby 380,180cfx

04-03-2017 07:05 PM
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Andy01

Senior Heliman

Brisbane, Australia

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My understanding of power out % is the position of the throttle stick to maintain the chosen rpm, so you will usually see the power out % increase as the lipo voltage drops, or as the lipo ages and becomes weaker. If you are getting low %, it may be because you have healthy high C rated lipos and/or your chosen rpm is well within the capabilities of the power system.

For info, I run 120mm tail blades on my Long Ranger at 1350rpm, and it holds very well. When I tried 1250rpm, the tail became a bit marginal in windy conditions.

Colin

Vario Long Ranger 700e
Seahawk 600
UH-1N 500
Baumann EC-145 800+ (coming soon )

04-04-2017 10:16 AM
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TailKiller

Senior Heliman

Panama City, FL

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Can't fly today.. to windy and more storms coming.
I set start up and change rate and gov gains to Low. I was spinning 105 tail blades, i put on 115's, I only have 5mm left before I hit the horizontal stab.
My batteries are new 5000mah 30c that I got just for this bird.
I will test the CC Tech explanation trm.
Thanks guys.

,Dennis
http://pcrcheliclub.com/
700 Astar Super Scale T-600 Bell 206 Trex 600 Naza H DX8

04-04-2017 05:44 PM
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TailKiller

Senior Heliman

Panama City, FL

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I finally got to fly today and it looks like the same results.
I put my flying HS on Idle2 so it's 100% flat. Seems the CC Tech was mistaken or I can't trust this esc any more.
To make the story short.. I'm posting the 2nd 5 min flight on a set of packs. There was a very brief 78% power out... but at end of flight and 44.5 volts the power out was only 71%.. no where near 91% as the esc set rpm states.
So I'm confused.. I knoe the Tech's know what they are talking about but, the esc is not recording those percentages.

,Dennis
http://pcrcheliclub.com/
700 Astar Super Scale T-600 Bell 206 Trex 600 Naza H DX8

04-10-2017 03:03 AM
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HelicopterScale Model RC Helicopters › Roban 700 2 Blade models Head Speeds
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