HIGHER HEAD SPEED?
 

Anybody have any solid information on raising the head speed on an aerohawk or similar?
Im running mine on lipos and the thing is so light the rotors dont really speed up that much to get it in the air which is ok in doors. Im thinking of maybe having a spare set of rotors/motor that I can swap out for flying out doors with a much higher head speed for a bit more control. Being outdoors there would be less chance of hitting the rotors on say( the door ) and damaging them.
I need to know what size pinion would be best and how much to modify the rotors.
Would it be best cut the ends, or along the full lenght?

I recently upgraded to a HBll 370 motor and I now have a spare 310 tuning motor so I dont have to keep changing pinions I can just swap them over.

Thanks.[sm=sunsmiley.gif][sm=sunsmiley.gif]

RE: HIGHER HEAD SPEED?
 

the super head would do it... kakkaa... 200 buck from heli hobby... but then that super head is CP...

RE: HIGHER HEAD SPEED?
 

what I really want to do is go with less pitch or less rotor area which will suit a higher head speed , which will give me a better chance outdoors.

Anybody have ideas?:D

RE: HIGHER HEAD SPEED?
 

Why not just go with shorter blades for outdoor flight?

I'm relatively new, so this is just as much a question as a suggestion. I think it would give you the higher headspeed, but I'm not sure what the negative effects might be.

Heli_fly

RE: HIGHER HEAD SPEED?
 

You can cut some of the width off the blades. I cut about 3/16 th off the edge of mine so it want have as much pitch or you can make a set of blades.

RE: HIGHER HEAD SPEED?
 

You might want to try an alternative approach which I think might be equivelant to increasing head speed -- adding mass to the rotor system.

I added a couple of those little wheel collets to the flybar, one on either side. This seems to work, I fly my 'hawk which is standard except for a 2S1P 1500mAH Kokkam and direct drive tail rotor. Its nice and steady in hover

RE: HIGHER HEAD SPEED?
 

Just noticed your upgrade comments, this was on the Aerohawk? You were able to do this without burning out the FET on the mixer board?

RE: HIGHER HEAD SPEED?
 

hey quaker, what'd you do with the 310?
Wanna sell it cheap?

RE: HIGHER HEAD SPEED?
 

If the aerohawk is anything like my dragonfly it hovers great but forward flight is a joke. Higher head speed is the answer.
I cut at least a third of my blades away, basicly running the trailing edge parallel to the leading edge from the tip to the root, removing all of the taper. I also stiffened the dragonflys head but I think the aerohawks head is ok stock. I also upgraded to a GWS EDF50 motor (note the motor only not the whole fan unit) to give the tail same much needed assistance and finally the stock battery was replaced with a 3s1p Etec 1200 pack. This gave me a hover head rpm of 1700, which is similar to a hornet FP.
The whole mod took about 2 hours to do and it now flies a hell of a lot better. It will now respond to cyclic in forward flight and the pitchup is reduced. Down side is the main motor will not last anywhere as long as stock - but they are cheap.


Once again this mod was on my Dragonfly but the principles are the same, if you want to get these little FP helis flying as well as just hover, the head speed has to go up.

BTW, adding the weights to the flybar as someone suggested increases the cyclic damping. This makes the thing even less responsive in forward flight, but makes hovering easier.

RE: HIGHER HEAD SPEED?
 

I need the 310 motor to save me having to change the pinion over all the time.A fast head speed is good outside but inside you dont need it and if you do have a crash you do a lot more damageplus it hovers fine indoors.Im also putting a piccolo one way main gear on in a couple of days to get rid of the reverse torque when you release the power, Ive had a few close ones because of this.The piccolo has the same ammount of teeth too which is well handy.
I managed to protect the fet`s by putting heatsinks on them to keep them cool which seems to work fine up to now which has been a few months. I think im gonna cut the blades and go a tooth or two up on the pinion and go from there, ill start with 5mm off the trailing edge and see how I go. thanks all for the advice.

RE: HIGHER HEAD SPEED?
 

One thing you can do to increase the head speed, cut your blades! The less drag on the rotors = greater speed. My web site shows how.

http://home.earthlink.net/~ibsniper HB Helipad

Also, the orion motor for the Mini-T is supposed to be an awsome coreless motor. I've heard claims of it working as well as a brushless.. (impressive in my opinion!) But I've still have yet to make that jump.. primarily because my HB work great stock. Just add the head stiffener, cut the rotors, and have fun!!!

Happy flying!!

RE: HIGHER HEAD SPEED?
 

I went ahead and cut the blades as you suggested with nothing but good results, thanks all for the advice:D

http://www.rcuniverse.com/forum/m_16...tm.htm#1664311

RE: HIGHER HEAD SPEED?
 

Hi quaker1

IMHO,
Another alternative is to use higher AmpereHour Li-Poly (3Cell). You using 3Cell 700mAH Li-Poly right? That battery is around what? 48gram? If u go for let say 3Cell Li-Poly 1500mAH Kokam, which is 98gram, U have heavy battery and therefore your chopper need to spin much faster in order to produce enough lift to take off. The extra AmpereHour will most likely give u the approx. same flight time as what u have.

Super-Hornet

RE: HIGHER HEAD SPEED?
 

Good to hear cut your blades to increase the head speed, you have just scratched the surface though. I see in your linked thread you estimate a head speed of 2000. I'm afraid its unlikely to be more 1500rpm with your current setup. I am just cracking 1700rpm (tacho-ed) with severely cut blades (see pic). it is now one of the most responsive FP micro helis I've flown, not perfect but a long way from stock.

RE: HIGHER HEAD SPEED?
 

I may try a higher gear ratio say 11 or 12 tooth pinion, and cut some more off the blades. The motor seems to be in its sweet spot at the moment.
You must be right about the head speed, your blades are quite a bit smaller than mine. Did you cut any off the lenght, is there any danger of too thin a blade flapping or flattening out at a high speed?
The battery im using is a 600mah. I have a home made li/ion thats about 105g and it really is stable with that, but obviously I prefer the lighter weight one and im going to get the head speed up to suit that battery.
I may go brushless but at the moment this motor seems to have enough power.

This is my heavy li/ion battery next to the lipo.

RE: HIGHER HEAD SPEED?
 

Quaker,

How are you mounting you LiPo to the AeroHawk, I notice on your Pic you appear to have a shelf underneath the Picoboard & Rx.

I'm waiting for my 2s 1200mAh Lipo packs to arrive, and hadn't thought about how I was going to mount them.

thanks,

Michael

RE: HIGHER HEAD SPEED?
 

I used two carbon rods held on by ali brackets that I turned at work. They have a grub srew that holds them onto the legs;)

RE: HIGHER HEAD SPEED?
 

cut my blades down some more today, flies even steadier now.
Took it outside in a slight breeze but had no problems with pitching up or being taken by the wind.:D:D:D:D:D