why lower headspeed

[rcflier1]

i,m new to scale heli's. i keep seeing lower head speeds when converting from pod and boom to scale body's, why. high speed=more stable? no? what if you want to still do a loop or 2? or is it that it looks more scale?

[Keyrigger]

Higher head speeds in a scale body usually add vibrations that can shake the model apart. Also, most large scale heads are designed with rotor speeds in the 1800rpm or less range. Lower head speeds are used as the most you might do with a helicopter model is a loop, roll, split S, or Immelmann turn. Everything is based on level flying with turns based on full scale, not what the head bangers do. While possible to run a standard 3D chassis in a scale body and not lower the head speed, it does not "sound" right at all. High lift scale blades allow lower speeds to develop the same or lower pitch in a hover using less power from the batteries. An average scale helicopter when setup for that will use between half and two thirds the power for the same flight time as a pod and boom, especially when the pod and boom is flown 3D.

We can't tell you what to do, only make our suggestions based on experience, and hopefully then you see why you are lowering the head speed on a scale helicopter. At most fields, a well flown scale helicopter will get more attention than a 3D pod and boom. Around here, few clubs had ever seen a helicopter flown in circuits before. They had also never seen a helicopter landed on water, hovered while a Bambi bucket filled, or seen a high angle approach landing executed with no hover at the end, just a single motion from forward flight to being on the ground. Look in my thread on the TOW Defender and in the recent posts, there is a video of the helicopter's POV of just such a landing. Hope this helps.

Don

[MotorRotor]

The main reason we run our pod and boomers at high rotor speed is because a helis cyclic response is directly related to the head speed....the higher the head speed, the faster the cyclic response. Lightening fast cyclic response results in rather twitchy looking scale flights. Consequently, by simply lowering the rotor speeds, one gets a much smoother response for much more scale looking flights.

As keyrigger stated, lower head speeds also consumes less power so one will get much longer flights from the same battery at a lower head speed.

[Varelco]

The idea of scale is to look and fly life like, having the rotor spinning at high headspeeds sounds and looks inaccurate and is wasted energy for the the type of flying scale helis do. Also higher headspeeds doesn't make a heli more stable .

[fossoman]

Doesnt reducing head speed reduce tail authority and make it Hold worse?
My problem Running 2 Blade Head 3150 KV Align Motor seems to bog down. MOTOR too hot. Tried taking off governer mode not as hot but . Climb out gentle even head speed drops violent shaking of heli. 11 tooth pinion. Dont know what pitch curve to use with this settup. Ordered 3500 KV motor. Fly in idle up land and kill with throttle hold. Doesnt shake everytime but most. Probably at 2000 or somewhere close headspeed give or take 100 to 150 rpms

[Keyrigger]

fossman:

You need to provide a lot more information before anyone that can help you out can determine what might be your issue. You need to post what the gearing is now, not just the pinion, what the weight is, how many cells you are running it on, what the chassis make is, and by the sounds of it, you are using a very old motor. You don't need lightning fast tail response to fly in a scale like manner. In fact, our models have a great deal more tail authority than the full size do. For my single 450 scale helicopter, I use a four blade head, 2580kv motor, 150 main gear, 13t pinion, and KBDD 450 tail blades and I have lots of tail power. It is an Align 450SEV2 chassis. Take care.

Don

[bladerunner469]

Originally Posted by Keyrigger

fossman:

You need to provide a lot more information before anyone that can help you out can determine what might be your issue. You need to post what the gearing is now, not just the pinion, what the weight is, how many cells you are running it on, what the chassis make is, and by the sounds of it, you are using a very old motor. You don't need lightning fast tail response to fly in a scale like manner. In fact, our models have a great deal more tail authority than the full size do. For my single 450 scale helicopter, I use a four blade head, 2580kv motor, 150 main gear, 13t pinion, and KBDD 450 tail blades and I have lots of tail power. It is an Align 450SEV2 chassis. Take care.

Don

+1 I use close to the same Setup on my Four Bladed 450 Heli's and they Fly fine!!!