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Old Jan 20, 2010, 09:19 AM
RC Addict
Oceanside, CA
Joined Oct 2009
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Question
Fooling the ICE Governor in set RPM mode

I'd like to fly my CC ICE 75 equipped Trex 500 in set RPM mode. However, with a 13T pinion and stock 1600 KV motor all it will let me set is 2400 rpm. I understand the headroom requirement but I know for a fact that the motor will carry 2600 RPM for an entire flight. I just switch to Idle up 2 and go from 90 to 95% flat for the last half of my flight time.

If I set my motor KV parameter to 1800 KV I think Castle Link will allow me to set 2600 rpm. The saved head speed data should be the same since it is based on the number of Poles and gearing correct? I'm guessing the KV data entry is just so Castle Link can do its 85% headroom math... Any major problem with trying this? Thanks...
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Old Jan 20, 2010, 10:09 AM
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Lidingo, Sweden
Joined Feb 2005
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I havent checked last few versions, but before it was never a hard limit, you got a warning but you could still press Apply on it, meaning you didnt have to "fool" it.

Is this no longer the case?
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Old Jan 20, 2010, 10:18 AM
A man with too many toys
United States
Joined Feb 2001
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The software will let you set any RPM. It just gives you a message that it might not work well but it will use the RPM anyway. Set it to 2600 and go fly. If the headspeed holds they you have a good setup. If it bogs then you need to set it lower or use a larger pinion.
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Old Jan 20, 2010, 11:04 AM
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I have a TRex 600ESP with a scorpion 4025-630 w/14T pinion and a cc ice hv80. When I try to set rpm it tells me that max rpm without giving me a warning is somewhere around 1980 rpm. I set it to 2200 rpm anyway and it holds it thru the entire flight with no problems.
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Old Jan 20, 2010, 12:17 PM
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Oceanside, CA
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Originally Posted by RC Man View Post
The software will let you set any RPM. It just gives you a message that it might not work well but it will use the RPM anyway. Set it to 2600 and go fly. If the headspeed holds they you have a good setup. If it bogs then you need to set it lower or use a larger pinion.
Yep, I went ahead and tried it this morning. It holds 2600 fine for the duration of the flight but bogs a little on pitch pumps. This is about the same as before with fixed endpoints and 95% flat. So, overall, I like this better than a flat throttle setup. At 95% flat I started out with 2750 and ended the flight with 2600. I like the consistent head speed better than the slightly higher starting head speed.
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Old Jan 20, 2010, 04:33 PM
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USA, GA, Statesboro
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Quote:
Originally Posted by dfrazier View Post
I have a TRex 600ESP with a scorpion 4025-630 w/14T pinion and a cc ice hv80. When I try to set rpm it tells me that max rpm without giving me a warning is somewhere around 1980 rpm. I set it to 2200 rpm anyway and it holds it thru the entire flight with no problems.
While the Castle Link will allow you to enter the Head Speed...I just punched in the setup I would run and for a 2200 HS the 16t looks like the better setup which in set rpm mode would give you 92.9% and will do a much better job of maintaining the HS. The 15t would be good up to 2100.

If you use the info box next to your desired HS you will get a throttle percentage that allows you to run between 70% and 94.9% w/o turning red. As a rule of thumb if you have 2 HS that are the same and with one gear option the info box says 94% and then you put on a larger pinion and the same HS with the larger pinion has a value of 85% in the info tab...both setups are running the same HS with different overheads and what you would see in performance would be the 95% would be easier on the batteries and the 85% would be harder but you would see better performance and the gov would hold a tighter HS. I personally like to try and hit 90% as it is the best of both words. I hope this helps.
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Old Jan 20, 2010, 06:40 PM
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Originally Posted by Clintstone View Post
While the Castle Link will allow you to enter the Head Speed...I just punched in the setup I would run and for a 2200 HS the 16t looks like the better setup which in set rpm mode would give you 92.9% and will do a much better job of maintaining the HS. The 15t would be good up to 2100.

If you use the info box next to your desired HS you will get a throttle percentage that allows you to run between 70% and 94.9% w/o turning red. As a rule of thumb if you have 2 HS that are the same and with one gear option the info box says 94% and then you put on a larger pinion and the same HS with the larger pinion has a value of 85% in the info tab...both setups are running the same HS with different overheads and what you would see in performance would be the 95% would be easier on the batteries and the 85% would be harder but you would see better performance and the gov would hold a tighter HS. I personally like to try and hit 90% as it is the best of both words. I hope this helps.
With the setup I am running at 2200 it only hits 100% motor power output under the hardest conditions which is only a few times a flight. When I lower it to my idle 1 at 2050 it never hits 100% So I think it's pretty good where its at on gearing.
The only problem I am still having is the shuddering(misfiring) during full collective punchouts. This problem actually has ruined a one-way bearing causing it to lock up. I have tried many different settings and it will not go away.
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Old Jan 20, 2010, 06:47 PM
MrE
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United States, WA, Gig Harbor
Joined Aug 2007
2,217 Posts
This isnt exactly on topic, but it does have to do with Set RPM gov mode.... how do you know when the GOV Gain is set "correctly"?

What are the signs of having it too low and too hi?

Can you tell from the logs?

Is it better to go a little hi or a little low?

Whats "just right"?
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Old Jan 21, 2010, 09:02 PM
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Joined Oct 2005
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The single most valuable parameter for setting up an ICE is the "power out" measurement. It tells you how often and how long the ESC pegs at 100% "throttle".

If you post that data, I'll be you'll be "flat topping" at 100% a lot of the time. The reason I think this is happening a lot is because your headspeed is not holding. I know you said prior to setting up the set rpm mode that you knew the rpm your system would handle, but that did not reflect how tightly the system could hold the headspeed under load. In my experience and assuming reasonable pitch ranges, the CC program is EXTREMELY accurate in predicting the best headspeeds that the governor can maintain under load. Given 10-12% headroom, the performance of the governor is nothing less than superb.

Mr E: Too much gain is easy to detect; the model will chatter or hunt the target rpm when in the highest of your headspeed choices. Find this point and back off a point of few from there. Too little gain will manifest with significant variation from your set rpm when the governor is operating with adequate headroom. IOW, you shouldn't see the head overspeed to any degree when it's unloaded, and you shouldn't see it lag/underspeed when the "power out" data curve shows the ESC was not flatlined at 100% for any longer than brief spikes under maximum load.

Ben Minor
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Old Jan 23, 2010, 09:52 PM
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Thanks Ben....
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Old Jan 23, 2010, 10:10 PM
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Do you guys recommend using the set rpm mode over the governer high mode? I'm using the lite 50 on the trex450 pro
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Old Jan 23, 2010, 11:19 PM
MrE
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United States, WA, Gig Harbor
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As far as Im concerned - set RPM is the only way to go. Its simpler to set up and it just works. No fiddling or guessing or trial and error adjustments. It just works
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Old Jan 24, 2010, 06:36 AM
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Joined Jun 2009
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thanks for the advice fellas. I'll give it a shot.
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Old Jan 26, 2010, 03:15 AM
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South Africa
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Quote:
Originally Posted by dfrazier View Post
...The only problem I am still having is the shuddering(misfiring) during full collective punchouts. This problem actually has ruined a one-way bearing causing it to lock up. I have tried many different settings and it will not go away.
I have exactly the same problem with ICE 50 on a TRex 500 with a Scorpion 3026-1400Kv motor running 15t pinion. It is setup in SET RPM mode with 2600 rpm as HS. It shudders badly on max power/pitch climbs, tried to reduce the gov gain and/or gyro gain makes no diffs. My throttle never hits 100% and averages at 85 to 90%. Ripple current is never more than 1V so batteries are good as well.

How do we fix this?
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Old Jan 26, 2010, 08:32 AM
RC Addict
Oceanside, CA
Joined Oct 2009
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Quote:
Originally Posted by Vinger View Post
I have exactly the same problem with ICE 50 on a TRex 500 with a Scorpion 3026-1400Kv motor running 15t pinion. It is setup in SET RPM mode with 2600 rpm as HS. It shudders badly on max power/pitch climbs, tried to reduce the gov gain and/or gyro gain makes no diffs. My throttle never hits 100% and averages at 85 to 90%. Ripple current is never more than 1V so batteries are good as well.

How do we fix this?
Make sure your setup is correct as far as motor pole count and gearing goes. Update to 3.20 firmware, try low timing (3 or less) and 8khz for PWM. Worth a try...Some of the earlier firmware, 2.18 in particular was awful and caused a lot of stuttering and worse on pitch pumps...
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