FBL Gyro T-Rex maiden with Spirit Pro (at last!)

[Heliman450]

Hi all, I managed to get round to doing this at long last! I did six sessions of test hovering and didn't make any changes to the Spirit Pro settings, only a small tail adjustment to ease the twitch on spool-up. As you can see it still needs a little more but it's better than the first test.

I gave the minimum of stick inputs to see how well the gyro was working in the 'Normal Stabilisation' mode. Looks good to me but it bobs up and down a bit too much. It was ,however, quite windy but despite this I think it held position quite well.

All feedback appreciated.



Phil, I fixed the link for you.. Steve

 

[Smoggie]

Hi Phil,

Looks like the 550 is steady as a rock, good work!

As for the embedded video, the problem was that the link you used was a Youtube search string, not a direct link to the video. You need to copy the direct url link then use the 'Insert Video' link to embed it in the post . The video url should look something like this: 'www.youtube.com/watch?v=bOfdfR_xE3A'

 

[Heliman450]

Hi Phil,

Looks like the 550 is steady as a rock, good work!

As for the embedded video, the problem was that the link you used was a Youtube search string, not a direct link to the video. You need to copy the direct url link then use the 'Insert Video' link to embed it in the post . The video url should look something like this: 'www.youtube.com/watch?v=bOfdfR_xE3A'

Great, thanks Steve! I'll look into perfecting my embedding skills

Any suggestions about the bobbing tendency? I'm thinking that I might need to invest in a Castle ESC but beforehand I'll do some investigations to see if I can stop it within the Spirit Pro settings.

 

[Smoggie]

It looked fine to me Phil.
If there is even the slightest breath of wind you will always get some up/down 'bobbing' which is caused as the wind blows over the rotor disk. To be honest it's also usually 'pilot induced' to some extent (we all do it) but you can reduce this by having a gentle pitch curve that's less sensitive to small stick movements. A governed headspeed so that the RPM isn't constantly changing also helps.

 

[Tony]

Great first flight!

As for the bobbing, try using a flat pitch curve. The throttle curve I use in Normal is 0 70 70 70 70. With the slow start it's not a problem and it will keep your motor from jumping like that.

And what smoggie was referring to with wind gusts is called Translational Lift. It happens when some nice smooth clean air passes over the rotor blades causing increased lift.

 

[trainrider06]

Hi Phil! She looks great! Very stable! Nice job too! As Steve said that could be just slight stick movements up and down, also the ground effects too! I could hear the RPM increasing as it went up and down, but that close to the ground like I said could be ground effects, but even with ground effects that baby was sweet stable! Try a flybar heli hovering that close and see what it does! As far as the ESC, what are you running now? Really instead of a Castle I'd recommend a Hobby Wing Platinum if you want a different one.

 

[Smoggie]

The pitch curve I use in Normal is 0 70 70 70 70.

Tony,

I'm sure you meant to type 'throttle curve'.. A flat pitch curve will of course give you a fixed pitch heli, which would be no fun at all.

 

[Tony]

Crap, posted that before taking a drink of coffee lmao. Edited.

 

[Heliman450]

Hi Rodney, at the moment, it's the Align unit that came with the heli. If you recall, she's a second hand purchase and I bought it without its installed gyro so that I could buy/test out a different gyro than my AR7200BX fitted to my Blade. I eventually got the Spirit Pro. I didn't want to change anything else until I really have to but I've seen the good reports on Hobby Wing, so maybe I'll go with that one. Let's see! Great fun this hobby, hey?

- - - Updated - - -

Crap, posted that before taking a drink of coffee lmao. Edited.

Hi Tony, great to see you around, hope all's going well.

Throttle curve is currently 7 Points 0-35-70-70-70-70-70. This gives a very nice steady spool up rate.

Pitch curve is also 7 Points (the range is -100% to +100% on my Jeti) 0-25-40-50-57-60-60 so a very gentle curve. Apart from the obvious changes to the sticks the heli does the bobbing even when I wasn't touching them. I can rest my hands on the Tx. holder and using the body harness makes the whole process very easy for such an old man as I am

When using a negative pitch to start with, the heli was setting down a bit harshly, hence, the slightly higher value. Maybe that could be increased a bit more as there's no tendency for it to blow away like my 450's.

Thanks for viewing and giving the feedback.

 

[Tony]

Unless you are looking for a very specific feel, I would take the curves down to 5 points. I have never run 7 points as I never have needed them. On mine, throttle curve is as stated above for normal and then a flat 85 and 100 in IU1 and 2. On my pitch curves, in Normal mode if you don't need all that negative pitch, run 46 48 50 75 100. This will give you about 2º of negative pitch, enough to hold it on the ground when you land. IU pitch curves leave linear.

And I as well as others heard the motor going up in speed. Are you that low on your stick to hit your lower end of the throttle curve? If so, might want to look into setting up 0º pitch at mid stick. Make sure you have a completely linear pitch curve when you do this though or you will be off. Mid stick needs to be 50% travel to set it up properly. I will bet if you do that, the helicopter will become much more stable and reduce the bobbing.

But again, translational lift can and will cause this too, especially when hovering less than 5' off the ground.

 

[Heliman450]

Unless you are looking for a very specific feel, I would take the curves down to 5 points. I have never run 7 points as I never have needed them. On mine, throttle curve is as stated above for normal and then a flat 85 and 100 in IU1 and 2. On my pitch curves, in Normal mode if you don't need all that negative pitch, run 46 48 50 75 100. This will give you about 2º of negative pitch, enough to hold it on the ground when you land. IU pitch curves leave linear.

And I as well as others heard the motor going up in speed. Are you that low on your stick to hit your lower end of the throttle curve? If so, might want to look into setting up 0º pitch at mid stick. Make sure you have a completely linear pitch curve when you do this though or you will be off. Mid stick needs to be 50% travel to set it up properly. I will bet if you do that, the helicopter will become much more stable and reduce the bobbing.

But again, translational lift can and will cause this too, especially when hovering less than 5' off the ground.

Hi Tony, I covered this in another thread. I have -12.0, 0.0 and +12.0 as per the Align instructions for the more aggressive 3D moves. I doubt I'll ever be using it but the set-up is perfect.

Lift-off occurs at about 56% stick with my current pitch curve, so I'm working with about 4% stick movement at the moment. I'll give it a boost to the top end and see how that goes. The throttle is at 70% long before the heli lifts off, so no problem there.

 

[Smoggie]

Throttle curve is currently 7 Points 0-35-70-70-70-70-70. This gives a very nice steady spool up rate.

Pitch curve is also 7 Points (the range is -100% to +100% on my Jeti) 0-25-40-50-57-60-60 so a very gentle curve.

My advice for what it's worth would be to use a straight line 'idle up' throttle curve at about 75% straight line accross the board. Use throttle hold to start and stop with soft start enabled on the ESC.. It makes no logical sense on an electric heli to use the collective pitch stick to start and stop the motor, that's just a throwback to nitro helis.

As for pitch curve you have a choice. if you plan on eventually doing aerobatics and inverted then best just get used to a straightline three point curve now i.e. 0-50-100% with +/-12 degrees pitch and zero pitch at mid stick. If on the other hand you want to fly more gentle 'scale' type flying then a soft curve with minimal negative would be better, something like 38-67-95% which will give you a straight line 'curve' with 4 degrees at mid stick and about -3 deg at bottom stick... The seven point curve you have right now with such limited positive pitch could be quite dangerous so i'd advise to change it ASAP.. in fact i'm surprised that you can even get off the ground with your pitch curve only going to 60%.

 

[Heliman450]

My advice for what it's worth would be to use a straight line 'idle up' throttle curve at about 75% straight line accross the board. Use throttle hold to start and stop with soft start enabled on the ESC.. It makes no logical sense on an electric heli to use the collective pitch stick to start and stop the motor, that's just a throwback to nitro helis.

As for pitch curve you have a choice. if you plan on eventually doing aerobatics and inverted then best just get used to a straightline three point curve now i.e. 0-50-100% with +/-12 degrees pitch and zero pitch at mid stick. If on the other hand you want to fly more gentle 'scale' type flying then a soft curve with minimal negative would be better, something like 38-67-95% which will give you a straight line 'curve' with 4 degrees at mid stick and about -3 deg at bottom stick... The seven point curve you have right now with such limited positive pitch could be quite dangerous so i'd advise to change it ASAP.. in fact i'm surprised that you can even get off the ground with your pitch curve only going to 60%.

Hi Steve, all well thought out feedback and advice is always welcome and much appreciated.

I've no plan to do aerobatics and inverted until I'm certain of my ability to do it on a simulator. I don't have any info on the ESC having bought the heli second hand so that's a matter for some research or straight replacement.

My eventual target is only scale flying but there's a way to go just yet. I already changed the pitch curve to five points as per Tony's advice and adjusted the top end. Seven was just a 'throw-back' from my JR ProPo as all curves were seven points. I don't see that as a 'danger'. As you probably noticed in the video, the heli is quite capable of getting well off the ground as it disappears for a second or so and returns with a nice gentle reduction in collective. Well under my control to stay in the field of view of the camera for my purposes in the test. Of course, when I graduate to flying around there will be appropriate settings to do it. Now that I'm more proficient at what I'm doing, I can work in the feedback from the most experienced Forum members as per your suggestions.

Up to now I have limited myself to mastering the building, setting up of a heli, which will do what I want it to do, not one capable of running away or just coming apart due to over enthusiasm/stupidity on my part. The Forum has helped tremendously in that journey and I look forward to the continuation along that way.

Bye for now!

 

[Smoggie]

Phil,

I think I misinterpreted your pitch curve. I used to Spektrum which uses different % values (0 to 100%) compared to the Jeti (-100 to +100). That makes all the difference! But in that case it does explain why we can hear the throttle and RPM rising and falling.. You will be flying on the 'sloping' part of the Normal mode throttle curve meaning that RPM varies as you move collective, like a FP heli.
Tony also made the same mistake in his pitch curve recommendation, so please dont follow it as written, that would be VERY bad!. Because of the way Jeti uses its % values you should be looking at something like:

Pitch: -15, +30, +75% (3 point straight line curve) that gives -2 deg at bottom stick, +4 deg at middle stick (hover point) and +9 deg at top stick.
Throttle: 70, 70, 70, 70, 70 (assuming idle up), or if you insist on 'normal mode': 0, 70 , 70 ,70 ,70

 

[Heliman450]

Phil,

I think I misinterpreted your pitch curve. I used to Spektrum which uses different % values (0 to 100%) compared to the Jeti (-100 to +100). That makes all the difference! But in that case it does explain why we can hear the throttle and RPM rising and falling.. You will be flying on the 'sloping' part of the Normal mode throttle curve meaning that RPM varies as you move collective, like a FP heli.
Tony also made the same mistake in his pitch curve recommendation, so please dont follow it as written, that would be VERY bad!. Because of the way Jeti uses its % values you should be looking at something like:

Pitch: -15, +30, +75% (3 point straight line curve) that gives -2 deg at bottom stick, +4 deg at middle stick (hover point) and +9 deg at top stick.
Throttle: 70, 70, 70, 70, 70 (assuming idle up), or if you insist on 'normal mode': 0, 70 , 70 ,70 ,70

Cheers Steve, I have already prepared the conversions a while ago to ensure that I don't make any mistakes with the changeover from the JR to Jeti, so no worries there. I'm not making a direct relationship between the two as recommended by the guys.

Thanks anyway for the heads up, it proves the professionalism of all those involved

 

[Smoggie]

Good that you had it covered Phil.

I think Jeti's -100-+100% approach is actually more logical, if the option was available on my Tx I'd have it that way too.

 

[Heliman450]

Phil,

I think I misinterpreted your pitch curve. I used to Spektrum which uses different % values (0 to 100%) compared to the Jeti (-100 to +100). That makes all the difference! But in that case it does explain why we can hear the throttle and RPM rising and falling.. You will be flying on the 'sloping' part of the Normal mode throttle curve meaning that RPM varies as you move collective, like a FP heli.
Tony also made the same mistake in his pitch curve recommendation, so please dont follow it as written, that would be VERY bad!. Because of the way Jeti uses its % values you should be looking at something like:

Pitch: -15, +30, +75% (3 point straight line curve) that gives -2 deg at bottom stick, +4 deg at middle stick (hover point) and +9 deg at top stick.
Throttle: 70, 70, 70, 70, 70 (assuming idle up), or if you insist on 'normal mode': 0, 70 , 70 ,70 ,70

Hi Steve, see the pdf below from my Excel sheet (not yet converted to my Jeti settings).

Taking up your point 'You will be flying on the 'sloping' part of the Normal mode throttle curve' as you can see with the superimposed curves, the throttle isn't doing this as when the heli's airborne all the stick movement is in the 50% plus range and the motor should be running constantly at 70% and only slows down when the stick reduces to point 2 (33.33%). This is my next target to fix and I'm already looking at the ESC.

Next flight, I'll go to the Idle-up recommendations to take the stick out of the equation. Fingers crossed for better weather soon!

View attachment 1.0x Heli Settings 23.04.16.pdf

 

[Heliman450]

Hi guys, I managed to track down the ESC information (it's the standard item described on page 30 onwards in the instruction manual). According to the current settings the tones indicate the following:

1. Brake - disabled
2. Electronic Timing - mid setting (6+ pole motors)
3. Battery Protection - high cut-off protection (single cell at 3.2V - reduced power. Single cell at 3.0V - no power)
4. Aircraft Setting - helicopter 1 soft start only (not soft start + governor)
5. Throttle Response - quick
6. BEC Output - power chord was disconnected by original owner in favour of a separate 2S power supply (needs checking with voltmeter to confirm, but serves no purpose now)

I'll check this out when next in the shop, activate the governor function and reduce the throttle response to 'standard' to better match my current flying capability (boring) maybe getting a bit more from the battery.

Bye for now!

 

[Smoggie]

Hi Steve, see the pdf below from my Excel sheet (not yet converted to my Jeti settings).

Taking up your point 'You will be flying on the 'sloping' part of the Normal mode throttle curve' as you can see with the superimposed curves, the throttle isn't doing this as when the heli's airborne all the stick movement is in the 50% plus range and the motor should be running constantly at 70% and only slows down when the stick reduces to point 2 (33.33%). This is my next target to fix and I'm already looking at the ESC.

Next flight, I'll go to the Idle-up recommendations to take the stick out of the equation. Fingers crossed for better weather soon!

View attachment 15760

Phil,
The graph is a good idea but unless I'm still misunderstanding something it doesnt seem to correlate with the settings you said that the flight in the video was using.

To quote what you said earlier:

Pitch curve is also 7 Points (the range is -100% to +100% on my Jeti) 0-25-40-50-57-60-60 so a very gentle curve.

And you said that you set it mechanically so that 100% travel = 12 degrees pitch?

So going by this the blade pitch and throttle 'opening' correlating to your 7 points on your pitch curve will be

1. 0% = 0 Degrees, 0% throttle
2. 25% = 3 Degrees, 35% throttle
3. 40% = 4.8 Degrees, 70% throttle
4. 50% = 6 degrees, 70% throttle
5. 57% = 6.8 degrees, 70% throttle
6. 60% = 7.2 Degrees, 70% throttle
7. 60% = 7.2 Degrees, 70% throttle

Most helis hover around 3-4 degrees of pitch so unless I'm out on something you will be hovering between points 2 and 3 on your pitch curve, which is on the sloping part of the throttle curve. this would explain why the throttle RPM can be heard to be hunting, unless my ears are mistaken too?

The other issue with that curve is that the upper 50% of stick travel only changes blade pitch by 1.2 degrees, which will make response VERY sluggish in that part of the travel... But i appreciate that you have already changed it.

 

[Heliman450]

Phil,
The graph is a good idea but unless I'm still misunderstanding something it doesnt seem to correlate with the settings you said that the flight in the video was using.

To quote what you said earlier:


And you said that you set it mechanically so that 100% travel = 12 degrees pitch?

So going by this the blade pitch and throttle 'opening' correlating to your 7 points on your pitch curve will be

1. 0% = 0 Degrees, 0% throttle
2. 25% = 3 Degrees, 35% throttle
3. 40% = 4.8 Degrees, 70% throttle
4. 50% = 6 degrees, 70% throttle
5. 57% = 6.8 degrees, 70% throttle
6. 60% = 7.2 Degrees, 70% throttle
7. 60% = 7.2 Degrees, 70% throttle

Most helis hover around 3-4 degrees of pitch so unless I'm out on something you will be hovering between points 2 and 3 on your pitch curve, which is on the sloping part of the throttle curve. this would explain why the throttle RPM can be heard to be hunting, unless my ears are mistaken too?

The other issue with that curve is that the upper 50% of stick travel only changes blade pitch by 1.2 degrees, which will make response VERY sluggish in that part of the travel... But i appreciate that you have already changed it.

Hi Steve, good to hear from you again and thanks for keeping 'on my case' it's great to have my own expert at hand as I don't have one at my flying club. I'll cover the situation as follows...........

My full range of pitch is 24 degrees (-12.0 to +12.0) as a combination of the mechanical set up and the fine tuning via the Spirit Pro. On my Jeti pitch is adjusted with a stick position min. = -100% to max. = +100% (mid. stick = 0% i.e. 0.0 degrees).

However, in my Jeti, the throttle operates on a conventional 0% to 100% scale so the missing part of your table is the stick position (note the red, dotted line going horizontally at the 50% value). My pitch curve as set gives me a working positive pitch of 7.2 degrees and the 'magic moment' occurs just after 50% stick. It will maintain a hover with about 60% stick and as the video shows, it can go out of shot with only a touch more stick. The throttle reaches the 70% at a stick position of 33.33%, so long before the heli lifts off.

One of the things I noticed in my early days in the hobby is that it's very easy for novices to overdo things due to their overall lack of knowledge of the Tx. (curves etc.) and physical coordination skills with the sticks, hence, I restrict what the heli can do until my understanding and skills catch up with each other.

When I get a bit more time, I'll edit my Excel sheet to better reflect what the Jeti curves look like.