My Heliartist UH 60 500 size project

[Windmanquebec]

Oups forgot to duplicate that post.
Installed tail linkage and mated with main frame.

[Windmanquebec]

Just maiden the frame. Had to increase positive pitch...I did set it at 12deg, but not enough with thoses blades and at this speed...increased them in the field a few degs (I have to check with my gauge how much) and then it was better at any of my 3 speeds.
Adjust tail gain---OK
Tracking was not perfect but ok for the check run.
Tail seam to vibrate a bit...maybe once in the frame it will be better...will see.
Need to change one rod end on the tail pushrod...look too loose for me.
I did 13 minutes with my 4500 mAh nano tech.I set the timer to 11 mins for now and will be adjusting once with the frame.

[Andy01]

I love low headspeeds, but I do think that 1400rpm may be a bit low for a 500 size, especially if 12° is not enough pitch to fly it.

Have you tried something closer to 1550rpm ? The heli should hover on about 5-6° IMO.

Tail authority is usually the first indication that the headspeed is too low, but with 4x 95mm on a 500, that shouldn't be a problem Even "worse" than the 4x 105mm on my 600 sized Seahawk.

A raised tail pod & boom like that does not have much support for the lateral torque moment, so don't fly too aggressively. I tested my Seahawk mechanics in the same way, but I can't remember if the tail vibrated or not.

Good luck

Colin

[Windmanquebec]

Ok my gearing is 14/162 with the 900 Kva.
It is giving me 1589 rpm with 22.2V 0.92 eff with the scorpion HS calc.
I want to run in governing mode, so the castle link program is giving me a max of 1476 before the warning. With 1500 I get the warning that at 96.5 it will be marginal, but I think that is ok?

When I maiden I had set up 1400, 1450 and 1500 rpm. the 2 first one where clearly not enough with 12 deg pitch. I think 1500 was ok but not perfect.

So probably as you said 1550 would be a good guess for 12 deg pitch.

To run at this speed (1550) in governing mode I will need a 15T that will give me as per the castle link software that the esc will run at 93.1% .

Do you think It would be better like that or does my ESC risk overheating?

[Andy01]

RPM = 900 x 22.2 x 0.9 x 15T / 162T = 1665rpm at 100% towards the end of a flight.

To govern to 1550rpm, you will be running ESC at 1550/1665 = 93.1%, which is close to perfect for a CC ESC. Close to 95%is great, and there is minimized risk of the ESC running hot. If it still runs hot, then you need ventilation. The lower the %, the more heat with a CC ESC.

Running a 14T, you be at 1554rpm at 100%, so 1550rpm would be 99.7%, which leaves you no headroom so the governor would not work very well.

Colin

[Windmanquebec]

Thanks to confirm my tought

[Windmanquebec]

Installed my 15T and set 3 gov speed to 1500(30), 1550(70) and 1589(100).

Ran and yes it is better with that little bit more of head speed. I think I loved the 1589 much. Look like it is hovering at 75% stick witch is approx 5-6 deg since I have 0 pitch at mid stick and +12 at high stick.
Tail is running fine now, but I just don't like not to have such a great lift with 12 deg.
I might try to go for +14 +15 and see what how it will go.

Any issue running such high pitch with my set up?
I know I have 4 main blades but they are so thin...



Or am I better to try with a 16T? it would give me 1687 at 95%

[Keyrigger]

It is normal to run 5 degrees or so at hover. I would recommend that you can do two things to change this lack of stick resolution from hover to full pitch. Don't change your amount of total pitch as it will bog the motor down rather than give you better performance.

One is to alter your pitch curve so that your mid stick is set to 5 degrees of pitch and that will give you more stick movement for the rest of the range. All of today's computer radios will let you set the pitch where and when you want it so it is a matter of sitting down with the radio and a pitch gauge and setting it to your liking.

The second is one that has been used by many scale flyers and that is to set the swash up so at mid stick, you will have 5 degrees of pitch. you will then set your maximum pitch as per normal at around 12 degrees, maximum. Your negative pitch range will now be down to about -2 to -3 degrees, which should suffice for an autorotation landing pitch.

I have set all of my large scale helicopters to have a standard pitch setup just as the 3D airframe would require and then I change my pitch curve so that I get the 5 degree (or what ever that model needs for hovering) at mid stick I manually set the negative up to my liking as I want more negative pitch with less movement in the event of an auto. Hope this helps.

Don

[Windmanquebec]

Originally Posted by Keyrigger

It is normal to run 5 degrees or so at hover. I would recommend...

Don

I know that hovering is done around 5 to 6 deg, I don't care that I have only 25% stick movement to go to +12 deg. The thing is I find that I don't have enough power (pitch positive) to have a fast reaction when going down to stop descent. And I don't even have my body on it witch will add more weight and being more difficult to stop a fast descent.

[Keyrigger]

Well, you can try adding pitch and do a full pitch climb-out, listening to the motor for bogging. When you have reached the maximum pitch where the motor does not bog, then you have the right setting for maximum pitch. Blades can and do stall if their angle of attack is too great but you will not hear this so much as see it in a loss of lift as you increase the pitch.

You will have a lot of adjusting to do with your flying style for scale. Heavy bodies are the norm and a lack of lightning fast response is also standard. You will need to plan your flight more carefully so as not to exceed the limits of the model. Be careful with descending through dirty air caused by the rotor wash as it will catch you off guard and can result in a condition called "settling under power". I have had that happen in the first couple of flights with my rather portly TOW Defender and it is not fun to get out of. I ran that helicopter with three different blade cords and never found that there was any noticeable lift lost with the very narrow cord 35mm Spin Blades compared to the current 51mm Rotor Techs. I changed to them for reasons related to competition flying. Good luck.

Don

[Andy01]

I agree with Don on both counts - set midstick to around 5° and trying to stop a descent into dirty air can end badly, no matter how much lift you have. I generally try not descend quickly vertically - better to descend while moving forwards, backwards or sideways - that way you pick up "clean" air.

If you are flying in a scale-like way, you should not need a fast response.

I have never used those narrow chord scale blades, but I am surprised that 4 blades at +12° and nearly 1600rpm does not have enough lift for scale-like flying, especially as a pod and boom. The fact that you are using around 5° of pitch to hover indicates that your lift is about right.

If, however, you are trying to fly in a fairly aggressive (sporty) way, then you will need to either modify your flying style to suit scale more, or raise the headspeed.

I get perfectly adequate response from my 2x 465mm asymmetrical (wide chord - wider than any 425mm Stealth blades I have flown) with a maximum of 10° of pitch (although it would be very rare for me to hit max pitch) and 1700rpm. Yes, the blades are longer and wider, and the headspeed is a little faster, but it is only 2 blades, not 4.

By all means try the wider blades if you already have them and see how it goes.

Colin

[Windmanquebec]

Thank you very much both for you input. Your are...this scale flying style I must get use to. This morning I will try with a 16T and get an extra 100 rpm to see how it react.

[Windmanquebec]

Went out with the 16T and that extra 100 rpm (1700) made the difference. I will go ahead now and install the frame in the fuselage

[Windmanquebec]

Navigation lights installed

Heliartist Uh-60 500 size (0 min 38 sec)

[mloo123]

Hi Windmanquebec,

Im currently starting my new project on 500size apache. Thinking of getting the carbonhobby scale blades like yours. May I ask are they of good quality?

Currently im using some unbranded CF blade (wide chord) and have difficulty in balancing and tracking them causing much vibrations ( the microbeast seems dun like it). So wanna changed them out with either the Align 420D or the carbonhobby scale blades.

Also like to ask is the Beastx doing fine for your heli? Mine drifts during hovering (probably due to vibes) but headlock is good. Have read somewhere the beastx not suited for scale...

Martin

[Andy01]

Martin

Try the Spin asymmetrical wide chord blades. I use the 465mm on my 500 sized UH-1N, and they work well.

Colin

[mloo123]

Hi Colin,

Thanks for the inputs.

However, the main gear is unique that comes with the heliartist Apache which is smaller at 120T due to narrow width body. Currently im using a 1200kv motor on 6s Lipo. With the smallest 12T pinion im getting heaps of headspeed and if install 4x wider chords blades im afraid will be running too hot.

Martin

[mloo123]

Hi Colin,

Thanks for informations.

However, the 500size apache frame comes with custom 120T main gear, which gives plentiful head speeds on my current 1200kv motor on 12T pinion with 6S Lipo, and thus an even wider chord 4 x blades will be overkill? Or do I need lower cells lipos for such gear ratios even with narrower chords blades?

[Andy01]

Wow. You seriously need a SLOWER motor

RPM = 1200 x 22.2 x 0.9 x 12T / 120T = 2398rpm at 100% throttle towards the end of the flight.

IMO you should be targeting around 1600rpm for a 4 blade 500 scale heli. I run my 2x 465mm UH-1N at 1700rpm, and it flies well.

To get to even 1700rpm would require you to govern at 70% which is likely to cause ESC overheating unless you have an active freewheeling ESC.

If running a "normal" ESC like CC Edge 75 of around between 90-95% governing, so IMO you need to aim for a 100% headspeed around 1800rpm. To get this you will need a motor around 900kV.

I would not suggest running less than 6s. 4s with a larger pinion would probably work, but at higher amps.

If you run wider chord blades faster they will just run at less pitch to achieve the same lift.

Colin

[mloo123]

In fact, I was modelling the below 500 size apache from heliartist, and din realize it was maybe the older version which accomodates the stock 162T main gear. The newer version (RC aerodyne) has a more scale look and thus makes a 120T main gear which eliminates the side protrusion marerial of the fuse to cover the 162T main gear.

AH-64 APACHE LONGBOW DESERT FLIGHT SCALE RC MODEL HELICOPTER 500 SIZE (4 min 25 sec)

Btw, I'm sorry to the thread starter for interupting his thread...