450 Head Speed Advice Sought

Cyclone 7

Member
Hi everyone,

Seeking confirmation on what head speed I should be looking at for my Tarot 450 Pro DFC - I've had a look at one or two head speed calculators which give marginally differing results and would rather rely on first hand experience & advice.

My flying style is mild sport/scale - no 3D /aerobatics other than for stall turns and other manouvres that the full size can realistically achieve.

My set up is;

Motor - Align 460MX 3200KV
FBL - AR7210BX
ESC - HobbyWing Platinum Pro 60A V4
Battery - 3S 2200 mAh
Curves(normal) - Pitch 40-46-50-75-100 (-2.8 to 11.4 degrees, 0 at 50%)
Throttle 85-inh-80-inh-85
TX - DX6e

Any advice would be most welcome and thanks in advance. Really come to appreciate the knowledge base that exists on RC-Help.
 

Cyclone 7

Member
Sorry, forgot a rather important bit of information!

Pinion = 11T & Main = 121T Helical (I have 12T & 13T spare pinions on hand if recommended).
 

Smoggie

Well-Known Member
I'd guess that for your flying style something like 2800RPM should work ok but personally I don't worry too much about the numbers, I just adjust by 'feel'. If the heli feels lethargic and mushy on collective then i'll increase the throttle curve until i get the responsiveness that i'm looking for. If I max out the curve and I'm still wanting more then a larger pinion is in order.

The opposite applies if the RPM seems to be screaming high and I'm burning through batteries too quick.

Based on your spec you will need to be running near 100% on the throttle curve and/or go up a pinion tooth to get the range of RPM that I'd personally be looking for, but it is a personal thing you might find that it's ok as it is. If running lower RPM be careful with the tail. The tail will get loose and blow out if you are down on revs.
 
Last edited:

Cyclone 7

Member
Thanks Smoggie - excellent simple advice and more or less what I had in the back of my mind, once I had a recommended/general head speed to work around. I mostly adjust pitch and throttle curves by feel, rather than by a set formula.
 

Cyclone 7

Member
On reflection, have decided to up the pinion to a 12T - you make a very good point Smoggie, re the throttle curve. Seems it would be destined to be a bit marginal using the 11T. Also the tail blow-out potential has been bothering me. Thanks again for the sound advice.
 

Dennis H

Member
On one of my 450's, I run 1800 rpm's. Sport flying only, and my Heli is fine with this.

I have others I run anywhere from 2200 to 2400 rpm's when I do a little more aggressive flying. FYI
 

Cyclone 7

Member
Thanks for the input Dennis - I am going to work both the 11T & 12T and see which gives the best overall result. Quite a range in head speed mentioned here already 1800 - 2800 RPM. The various calculators/equation come up with 2800 - 3100 RPM based on my set-up and using a 12T at 85% motor peak efficiency(which I know can be a bit subjective). Trial and error time I think whilst bearing in mind comments above. Thanks again.
 

murankar

Staff member
I fly my 450s around 3000 to 3200 rpm. I usually run about 12 to 13° of pitch. When I gear the drive train in to have about 3500 total headspeed. I don't fly that high, it's for the governor. You will need some head room if you run a governor.

As Smoogie said gonby feel. Start at a number and adjust from there. If you keep around 3100 there is no reason you can't get 6.5 minute sport flights.
 

Cyclone 7

Member
I fly my 450s around 3000 to 3200 rpm. I usually run about 12 to 13° of pitch. When I gear the drive train in to have about 3500 total headspeed. I don't fly that high, it's for the governor. You will need some head room if you run a governor.

As Smoogie said gonby feel. Start at a number and adjust from there. If you keep around 3100 there is no reason you can't get 6.5 minute sport flights.

Thanks for the input muranka - I'm leaning toward the 2,800 level at the moment as I like the lower head speed. Although the HW60A v4 has an excellent governor, I'm running everything through the AR7210BX for the sake of set up - for the moment that is, at least.
 

murankar

Staff member
Just keep testing. 2800 should be a good starting point. I wouldn't be surprised if you end up around 3000.
 

Smoggie

Well-Known Member
Cyclone 7,

I completely forgot to mention that I made up an excel tool for estimating what RPM you are likely to need for a heli of a certain size and weight and for a certain flight style (find attached).

Note that this tool is different to all the other headspeed calculators out there which are all based on estimating mechanically achievable RPM based on your power system and gearing etc. The tool I made is different in that it estimates what RPM you will need to fly. If your setup is mechanically capable of achieving it is another issue and would be where the likes of the 'Mr Mel' type calculator comes in.
 

Attachments

  • headspeeds_V1.3.zip
    14.4 KB · Views: 16

Cyclone 7

Member
Thanks Smoggie - excellent! Will play with it this evening once I've put the heli on the scale to get the exact all up weight. A quick check, using your 'No'/average weight (algorithm?) option seems to point to 2,500 for scale & 2,800 for mild sport which is more or less where I was leaning. Will also try the 3,000 mark though. As you say, trial and error to find a personal preference.

Thanks again - your help & advice(and everyone else's) much appreciated - a very useful tool to have, indeed. Will report back on results.
 

Cyclone 7

Member
@Smoggie - all good. Your Excel tool with the exact AUW of the Tarot as 913g, gives Scale RPM of 2,474 & Sport RPM of 2,860. Thanks for the help - data coincides with the other HS calculators.

That is a very useful tool - thanks again.
 

Smoggie

Well-Known Member
Good that you find the little excel tool useful. Good luck with the maiden flight when it comes.
 
Top Bottom