Tony
Staff member
Shouldn't you be able to figure that out with the max head speed though?
v*kv= max motor rpm
Main/Pinion= Drive ratio
Drive ratio / max motor rpm = Final Drive Ratio
Lets say that you have a 150t main, 14t pinion, 3550kv motor running on 3s. It would look something like below.
12.6 * 3550 = 44730
150 / 14 = 10.714
44730 / 10.714 = 4174.91 Max Head RPM at full 100% throttle
Half of that, or mid stick 50% throttle would be 2087.455
1/4 throttle would be 1043.728
3/4 throttle would be 5218.183
Right there you can figure out your total head speed throughout the whole throttle range. I myself have never trusted apps because they use sound, not light to figure out the blade speed. If this app works for you, great. But I would do it as i have described above. YOu are worried about over spinning the head because your pinion is too big, this way would keep you under that and keep the heli safe.
v*kv= max motor rpm
Main/Pinion= Drive ratio
Drive ratio / max motor rpm = Final Drive Ratio
Lets say that you have a 150t main, 14t pinion, 3550kv motor running on 3s. It would look something like below.
12.6 * 3550 = 44730
150 / 14 = 10.714
44730 / 10.714 = 4174.91 Max Head RPM at full 100% throttle
Half of that, or mid stick 50% throttle would be 2087.455
1/4 throttle would be 1043.728
3/4 throttle would be 5218.183
Right there you can figure out your total head speed throughout the whole throttle range. I myself have never trusted apps because they use sound, not light to figure out the blade speed. If this app works for you, great. But I would do it as i have described above. YOu are worried about over spinning the head because your pinion is too big, this way would keep you under that and keep the heli safe.
Lee
Well-Known Member
Theoretical Head speed and actual head speed can be very different. All will depend on the drive trains efficiency, quality of the battery, AUW etc. I have the app and i also have the Casle Creations ESC that tells you exactly what HS you have. My ESC gave a reading of 2330 the app said it was 2336. So pretty accurate, for me anyway.
murankar
Staff member
Here is the concern I have, its head speed with a 16t (supplied) pinion. This set up would reduce flight time and give an insane amount of speed. I know I can set the throttle curve to let's say 80%. Now the math would be to figure out full head speed and multiply by .80. This could work for both idle up and normal.
Now I guess would it be easier to set the governor or use the throttle curve?
After all that I would like to know my actual speed just to make sure I am in a suitable range.
Here are the details of the "stock" set up.
Main gear 120t
Pinion 16t (options are 14t-18t)
Battery 11.1 volt 2200 man
motor 3595kv 400 watts
There are some other issues that can be fixed as I go. My noobness at this is causing me to think this out. Plus a lot of Info for this build is unknown and I will have to wait till the kit arrives. This will be in my write up.
Now I guess would it be easier to set the governor or use the throttle curve?
After all that I would like to know my actual speed just to make sure I am in a suitable range.
Here are the details of the "stock" set up.
Main gear 120t
Pinion 16t (options are 14t-18t)
Battery 11.1 volt 2200 man
motor 3595kv 400 watts
There are some other issues that can be fixed as I go. My noobness at this is causing me to think this out. Plus a lot of Info for this build is unknown and I will have to wait till the kit arrives. This will be in my write up.
coolgabsi
Super Mod & DEAL KING!
ok so lets do this.. here are your head speed options when looking at it..
Here is your headspeed graph for a 14t Pinion:
Here is your headspeed graph at 15t pinion
Here is your headspeed graph at 16t pinion
Remember the efficiency of the motor is assumed at 90 percent.. and the "low voltage" is at 10.3 at a drained battery with may be 200 mah left.. so forget the low.. .. which is way lower than recommended.. you never wanna go less than 80 percent of 2200mah available to you.
So looking at this.. you have a 16t pinion you are looking at headspeed of 5500rpm! TOO HIGH for esp a beginner. Your bird will scream.. will be extremely twitchy on the sticks.. you will hate it starting off.. and then any crash will cost a LOT.. NOT recommended for someone who is new or starting off.
Now with my setup.. I get a headpseed of. 3700 rpm.. and is more than enough on what I can do.. or I will need.
Again adding to that.. I will wanna add that the higher headpseed will mean more bog in the motor as you will have lesser torque. The motor KV you are using.. is that a recomended motor? or something you picked out ? Check the manual and see what is recommended on this motor.. if this is a kit with a motor and pinion.. check their throttle curves. At too high of an rpm.. be it metal head or plastic.. tooo much load can disintegrate the head. or bend it.. So have to be a bit careful.. and add to that.. usually.. the tail runs (usually) 1:5 ratio.. so your tail will be going at 5500*5 = @_@ .. that means it wont be recommended to probably run any plastic blades but carbon blades.. as you can see.. things need to be taken care of..
I would aim for 3700-3800.. that in itself is higher rpm than a stock straight gear trex 450 pro will do.. ( I have helical with a lower gear ratio so I get 3700)
Here is your headspeed graph for a 14t Pinion:
Here is your headspeed graph at 15t pinion
Here is your headspeed graph at 16t pinion
Remember the efficiency of the motor is assumed at 90 percent.. and the "low voltage" is at 10.3 at a drained battery with may be 200 mah left.. so forget the low.. .. which is way lower than recommended.. you never wanna go less than 80 percent of 2200mah available to you.
So looking at this.. you have a 16t pinion you are looking at headspeed of 5500rpm! TOO HIGH for esp a beginner. Your bird will scream.. will be extremely twitchy on the sticks.. you will hate it starting off.. and then any crash will cost a LOT.. NOT recommended for someone who is new or starting off.
Now with my setup.. I get a headpseed of. 3700 rpm.. and is more than enough on what I can do.. or I will need.
Again adding to that.. I will wanna add that the higher headpseed will mean more bog in the motor as you will have lesser torque. The motor KV you are using.. is that a recomended motor? or something you picked out ? Check the manual and see what is recommended on this motor.. if this is a kit with a motor and pinion.. check their throttle curves. At too high of an rpm.. be it metal head or plastic.. tooo much load can disintegrate the head. or bend it.. So have to be a bit careful.. and add to that.. usually.. the tail runs (usually) 1:5 ratio.. so your tail will be going at 5500*5 = @_@ .. that means it wont be recommended to probably run any plastic blades but carbon blades.. as you can see.. things need to be taken care of..
I would aim for 3700-3800.. that in itself is higher rpm than a stock straight gear trex 450 pro will do.. ( I have helical with a lower gear ratio so I get 3700)
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murankar
Staff member
Thank you Gaba
Ok your numbers are higher than I calculate. Then again I assumed 80% efficiency. Either way I am going to be way high on my numbers. Even at the lowest possible pinion.
These dang pinions are killing me. So far this is my second kit and my second time having issues with this topic. One day I'll get this down.
Ok your numbers are higher than I calculate. Then again I assumed 80% efficiency. Either way I am going to be way high on my numbers. Even at the lowest possible pinion.
These dang pinions are killing me. So far this is my second kit and my second time having issues with this topic. One day I'll get this down.
coolgabsi
Super Mod & DEAL KING!
I recommend the lowest possible pinion with the motor and stock gear.. and then just make your mind on an rpm.. 3800? 3700? 3600? 3500? 4000? lol just whatever you want.. and calculate the throttle percentage that you can max out on your RX.. 75.. 80.. 90 whatever.. and if you feel the heli is not stable.. or too twitchy you can just go up or down in HS.. just as simply by changin the highest rpm percentage on your tx..
A beginner's rpm is safest at 3600 ... or even 3700.. gives your enough head speed to even do autos.. and learn.. 3400 and 3300 are also very good and doable head speeds.. you will have a very stable and smooth heli..
every heli frame design has a lower limit also.. lower than that and you will have toilet bowl kind oscillations. or just vibrations in general cause the gereal harmonic resonance will not be met.. I dont remember if you were there still when that guy flew his Logo 600 .. he was running 1200 RPM!!!!!!!! And I run 2150 on my 600.. And his bird was slow and smooth and could even do slow and smooth 3D. no its not that LOGO is special.. just that the guy realized the lower limit of the frame.. and kept his headpseed enough so even pitching it .. it wont vibrate..
So you make a decision and go with it!
A beginner's rpm is safest at 3600 ... or even 3700.. gives your enough head speed to even do autos.. and learn.. 3400 and 3300 are also very good and doable head speeds.. you will have a very stable and smooth heli..
every heli frame design has a lower limit also.. lower than that and you will have toilet bowl kind oscillations. or just vibrations in general cause the gereal harmonic resonance will not be met.. I dont remember if you were there still when that guy flew his Logo 600 .. he was running 1200 RPM!!!!!!!! And I run 2150 on my 600.. And his bird was slow and smooth and could even do slow and smooth 3D. no its not that LOGO is special.. just that the guy realized the lower limit of the frame.. and kept his headpseed enough so even pitching it .. it wont vibrate..
So you make a decision and go with it!
murankar
Staff member
That kinda was what I was thinking. Wasn't 100% sure how that would work. One down side to this kit is that you have to really know your stuff. So much info is kind of missing in the downloadable manual. I hope the actual manual has the info needed.
Good news is it shipped while I was home at lunch.
Good news is it shipped while I was home at lunch.
murankar
Staff member
Well a main hobbies just gave me a bit of encouragement about this pinion issue. I asked them what modes I needed for the MSH pinion to fit on my 3.17 motor shaft. The reason I asked is because the pinion bore nor the motor shaft dimensions are never mentioned. I searched high and low for the sizes, the only thing I found was a viper and a KDE direct motors which were shown in the parts list at a main. Those shafts are 3.5mm and thats why I had to ask. Tonight I finally got a response on my question and it is promising. They said I can use the Align pinions on this thing, if thats the case I already have the 11T installed and it will help keep the head speed down along with maintaining torque. Another plus is that my battery efficiency should still be rather good, about 6.5 minutes per flight. Again I will include this info in my final write up it is works.
heli-maniac
New Member
yes Aline dose make the 3.17 and 3.5 if the teeth pitch is wrong if im thinking right you can open the 3.17 to a 3.5 i have done that once with real good luck
i have not seen much on this heli is that a belt drive running from the motor to the main gear
i have not seen much on this heli is that a belt drive running from the motor to the main gear
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murankar
Staff member
The belt for the tail runs from the tail, around the main gear to the motor pinion. The Pinion does not touch the main gear in any way. This makes for a more quite and smoother running heli. There is less power loss to the tail and when the belt breaks you pretty much screwed.
My tracking numbers finally work. Just waiting to watch its progress to the house.
My tracking numbers finally work. Just waiting to watch its progress to the house.
heli-maniac
New Member
were did you buy it from and what kind of shipping isit coming buy do you think you will have it buy the weekend of when
sorry i went back to the first post and found the answer to this
sorry i went back to the first post and found the answer to this
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Tony
Staff member
I would use the Gov. If you just use T-Curve, then your power is only going to be 80%. If you use the Gov, then you will have 100% power with 80% speed. Hope you get it all figured out soon. Hell, hope to see it in the air soon. I may have the RCH Heli in the air first with the changes that I just heard about.
murankar
Staff member
Well I gots the latest on the kit. It is in Mesquite, TX. Should be here on Monday unless ups decides to deliver tomorrow. I didn't pay for Saturday delivery so I think it will be monday before i see it.
Now I am having Laptop issues, hardware issues that is. Happy Happy Joy Joy.
Now I am having Laptop issues, hardware issues that is. Happy Happy Joy Joy.