With everything being the same. Changing the pinion should result in lowering or increasing the headspeed. The balance is the lost of torque if the headspeed increases. At least that's how I understand it.

Originally Posted by derelicte

I don't know if I believe that that is really a 6ch heli. the instructions imply (to me) that in order to get it to fly upside down, you need to flip the blades over.

a v911 will fly upside down too if you turn the blades over...

No, It does not look like it can really change pitch on its rotor blades. It probably just rotates the motors in reverse and usies flatter blades.

I think Walkera had a variable pitch co-axial. I didn't see the point though.

Originally Posted by Daryoon

mSR and 9958 motors come with 8 teeth.

we know at least one person on here have tout the virtue of using the 9958 8teeth motor in his v911.

My first V911 came with a defective motor so I inserted the Xieda 9958's motor on my V911. It flies great! A cheap 9958 motor is $4.24 with free shipping. More teeth translates to higher main rotor rpm. It does not mean faster forward speed.

My Xieda 9958's toilet bowl effect did not migrate to my V911.

Originally Posted by Daryoon

With everything being the same. Changing the pinion should result in lowering or increasing the headspeed. The balance is the lost of torque if the headspeed increases. At least that's how I understand it.

If the head rotate faster we would have more lift using the same blades. With the same weight, the excessive lift will shoot the heli up.

To keep it in hover, we will end up with the same head speed.

The only difference is that the motor would be running at a different speed. Whether it like that better or worse will depend on the motor and ESC design.

Hey all, new v911 owner here! Having a little trouble putting a new set of blades and flybar on with getting the linkages in place. I wasnt able to find a troubleshooting tutorial so i figured i'd post here. I also have a new main gear id like to replace if anyone has any experience with these i would greatly appreciate it!

I was just thinking that at a certain forward speed the heli doesn't have enough lift even at full throttle to keep the heli up in the air. I wonder what kind of gears could increase this capability? I guess that would just translate to a greater lifting power. I measured my heli generates something like 50g of thrust, maybe with a tooth more or less it would be a different number?

Originally Posted by Proud Infidel

My first V911 came with a defective motor so I inserted the Xieda 9958's motor on my V911. It flies great! A cheap 9958 motor is $4.24 with free shipping. More teeth translates to higher main rotor rpm. It does not mean faster forward speed.

My Xieda 9958's toilet bowl effect did not migrate to my V911.

I thought more teeth would result in a lower rpm to turn the blades at the same speed as the stock gear. For every revolution of the pinion gear, the main gear would move 1 tooth further resulting in more turns per revolution of the pinion gear. My only concern is with the gear mesh. Have you noticed the brass gear biting into the plastic main gear teeth at all?

Originally Posted by Wasp09

If the head rotate faster we would have more lift using the same blades. With the same weight, the excessive lift will shoot the heli up.

To keep it in hover, we will end up with the same head speed.

The only difference is that the motor would be running at a different speed. Whether it like that better or worse will depend on the motor and ESC design.

You are correct, if you were running at 100% throttle all the time. Of course if the change in gear ratio makes the head speed higher, thereby giving more lift...you simply don't use as much throttle to hover. The goal is to gain the additional lift for fast forward flight. Hope that makes sense.

Originally Posted by andur

I was just thinking that at a certain forward speed the heli doesn't have enough lift even at full throttle to keep the heli up in the air. I wonder what kind of gears could increase this capability? I guess that would just translate to a greater lifting power. I measured my heli generates something like 50g of thrust, maybe with a tooth more or less it would be a different number?

You got the idea. The increase headspeed should give more lift...so you can maintain altitude while flying fast forward flight.

As far as thrust, the increase headspeed also increases the load on the motor, which in turn may heat up the motor more and therefore reduces it's efficiency...thus possibly negating any gains at all. It's really all theory. We gotta put in practice to see if the mod is worth it.

Originally Posted by Killer Bee

I thought more teeth would result in a lower rpm to turn the blades at the same speed as the stock gear. For every revolution of the pinion gear, the main gear would move 1 tooth further resulting in more turns per revolution of the pinion gear. My only concern is with the gear mesh. Have you noticed the brass gear biting into the plastic main gear teeth at all?

More main gear teeth equates to a lower head speed. More pinion teeth, equates to a higher head speed.

You can play with this calculator to see the relationship between the gear ratio.

http://www.rcuniverse.com/community/heliwizard.cfm

You can ignore the "Tail Rotor Pinion" in that calculator above. Because the v911 tail is directly driven by a motor.

Anyways, use an estimated 33000 RPM for the Engine RPM.

The v911 has a main gear of: 84
It's pinion is: 7

The 9958 has a main gear of: 74
It's pinion is: 8

The mSR has a main gear of 64
It's pinion is: 8

Originally Posted by derelicte

I don't know if I believe that that is really a 6ch heli. the instructions imply (to me) that in order to get it to fly upside down, you need to flip the blades over.

a v911 will fly upside down too if you turn the blades over...

Actually, no.
You'd need to spin the main motor backwards.
(flipping a propeller doesn't make it blow the other way.)
And I guess the tail.
But the gyro and control algorithm would be all confused.

I'm guessing from the pics that on the coax they not only flip the blades, but also swap the pairs.
This would give you the result you need.
My brain can't figure out if the gyro would be confused. Maybe they have a switch to change the algoritm.

Originally Posted by RicksterRC

Actually, no.
You'd need to spin the main motor backwards.
(flipping a propeller doesn't make it blow the other way.)
And I guess the tail.
But the gyro and control algorithm would be all confused.

I'm guessing from the pics that on the coax they not only flip the blades, but also swap the pairs.
This would give you the result you need.
My brain can't figure out if the gyro would be confused. Maybe they have a switch to change the algoritm.

flip the blades and reverse the motor, like you said. the gyro works fine.

MSR Inverted, Pilot Sam Tse (HHF) Kaz (HHF) (0 min 42 sec)

http://www.helifreak.com/showthread.php?t=183527

edit: corrected statement

Originally Posted by Daryoon

More main gear teeth equates to a lower head speed. More pinion teeth, equates to a higher head speed.

Or you could say it as... More pinion gear teeth equates to high head speed which means the motor runs at a lower rpm to maintain altitute. This would also mean greater performance/lift at max rpm. I guess my mistake was reading his repsonse as higher Motor rpm vs higher Rotor rpm which is what was actually said... The motor rpm would decrease for the same amount of lift. I think the 9958 is a worthwhile transplant motor for added performance.

Originally Posted by Daryoon

....
As far as thrust, the increase headspeed also increases the load on the motor, which in turn may heat up the motor more and therefore reduces it's efficiency...thus possibly negating any gains at all. It's really all theory. We gotta put in practice to see if the mod is worth it.

More main gear teeth equates to a lower head speed. More pinion teeth, equates to a higher head speed.

You can play with this calculator to see the relationship between the gear ratio.

http://www.rcuniverse.com/community/heliwizard.cfm

You can ignore the "Tail Rotor Pinion" in that calculator above. Because the v911 tail is directly driven by a motor.

Anyways, use an estimated 33000 RPM for the Engine RPM.

The v911 has a main gear of: 84
It's pinion is: 7

The 9958 has a main gear of: 74
It's pinion is: 8

The mSR has a main gear of 64
It's pinion is: 8

So the V911 has a gear ratio of 12:1, the 9958 of 9:1 and the mSR 8:1 - How much do you actually gain if you go from 8:1 to 12:1 ... or better from 12:1 to 10 and a bit to one (or where do I have my mistake here ??? ...)

Originally Posted by Killer Bee

Have you noticed the brass gear biting into the plastic main gear teeth at all?

No, when I turn the main rotor by hand, there's no resistance at all. I've flown it many times. Currently, I'm flying my newest V911 which has the regular motor. I have three full functioning V911s, but I don't need to fly all three of them. I have a Solo Pro 270 that I fly also.

Originally Posted by erdnuckel2

didnt we have that discussion already? scroll down! ever seen a STOCK coax fly inverted??
And the ... DIY? what is THAT supposed to mean??

DIY means you hold it in your hand and move it all around in the air (mouth noises optional) like it's flying 3-D ... LOL!

Originally Posted by aidenXudfame

Hey all, new v911 owner here! Having a little trouble putting a new set of blades and flybar on with getting the linkages in place. I wasnt able to find a troubleshooting tutorial so i figured i'd post here. I also have a new main gear id like to replace if anyone has any experience with these i would greatly appreciate it!

Anyone have any advice?