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Midland Helicopters . HeliProz . ZoomsHobbies

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Kyosho Caliber 30 & 60 - Concept - Nexus > Caliber 5 ratio
 
 
3410253
Senior Heliman
Location: TUCSON,AZ

How do you come up with the gear ratio

cluth bell has 26 over to a 50 gear ( thru belt)
m/s gear 70 to pinon 14
I would like to see the formula

THANKS
CHUCK
03-11-2008 06:47 PM
 
 
rguimaraes
Heliman
Location: Portugal - but born in England!

The total ratio is 1 : 9.615

How to get the 9.651???

Simple!

The total ratio is the product of both ratios.

Each ratio is the number of teeth of the pinion over the number of teeth on the gear

R = 26/50 * 14/70 =
R = 0.52 * 0.2
R = 0.104

R = 1/X = 0.104
X = 9.651

Ratio = 1 : 9.651

Regards
RG
03-12-2008 01:54 AM
 
 
dkshema
rrProfessor
Location: Cedar Rapids, IA

That would be 9.615:1 -- your fingers are playing games with your typing.

Pulley on clutch has 26 teeth
Pulley on top of counter shaft has 50 teeth.

50 divided by 26 = 1.923. The clutch pulley turns 1.923 revolutions for each revolution of the pulley on top of the countershaft.

The pinion on the bottom of the countershaft turns at the same rate as the 50-tooth pulley above it when the one-way clutch is engaged. That would be a 1:1 ratio. Not all that interesting in the grand scheme.

The stock C5 has a 14-tooth pinion on the bottom of the countershaft. It turns a 70-tooth gear that drives the main rotor shaft.

70 divided by 14 = 5. The countershaft turns 5 revolutions for each revolution of the 70 tooth gear.

The reduction ratio of 5:1 for the pinion/main gear combo multiplied by the 1.923:1 reduction ratio of the clutch pulley to 50-tooth pulley yields an overall reduction ratio -- motor to main rotor -- of 1.923 x 5 = 9.615:1.

The motor turns 9.615 revolutions for each revolution of the main rotor head.

If your motor is turning at 17,000 RPM, the calculated head speed is 17,000 / 9.615 = 1768 and change.

The tail rotor turns at the same RPM as the countershaft does, the front and rear pulleys have the same number of teeth. The TR turns 5 revolutions for every revolution of the Main Rotor. This is where Kyosho gets their 5:1 ratio for the tail. The reduction ratio for the motor to the tail rotor is that 1.923:1 number calculated above. At a motor RPM of 17,000, the TR is turning 17,000 / 1.923 = 8840 and change.

-----

Swap out the stock 14-tooth pinion for the optional 15-tooth pinion, the numbers change to:

Motor to counter shaft ratio: 50 / 26 = 1.923 (this number stays the same as the original example as the teeth don't change)

Countershaft to main gear ratio: 70 / 15 = 4.666666667

Overall reduction ratio = 1.923 x 4.6666666667 = 8.974:1.

If your motor is turning at 17,000 RPM, the calculated head speed is 17,000 / 8.974 = 1894 and change.

The tail rotor would still be running at 17,000 / 1.923 = 8840 and change.

However, the Main Rotor to Tail Rotor ratio in this case is 4.6667 : 1.

-----

* Making the World a Better Place -- One Helicopter at a time! *

Dave
03-12-2008 02:33 AM
 
 
3410253
Senior Heliman
Location: TUCSON,AZ

Thanks
that's just what I was looking for
Thanks Dave
03-12-2008 02:45 AM
 
 
aliensil
Senior Heliman
Location: Laredo Tx

Ratio on real 3D capable machines like Raptors and Trexes 600N are 8.5:1, this will give you headspeeds from 2000 rpm and up, without burning your engine. More rpm's = efficiency and hapiness.

Flying pigs 8,000 feet above Sea level
03-12-2008 02:35 PM
 
 
heli-cuzz
Veteran
Location: Pittston, Pa. USA

Quote 
Ratio on real 3D capable machines like Raptors and Trexes 600N are 8.5:1, this will give you headspeeds from 2000 rpm and up

I don't think they're anymore 3D capable, just more popular.
9.1:1 on my C-5 and the headspeeds are 1850-1950-2150.
1950 will do slamming 3D if you're good with collective and cyclic management.

Life Rotors On!!!
03-13-2008 10:26 PM
 
 
aliensil
Senior Heliman
Location: Laredo Tx

Hi Brian

Just remember that OS Hyper manual says “Power output/1.9 ps-17,000 rpm“ at 9.1:1 ratio means 1868 rpm (1.9ps), at stock 9.6:1 “1770“ what a joke. On the other side 8.5:1 machines like hated raptors and Trexes nitro run 8.5:1 ratios---2000rpm at pure 1.9 ps.

Of course we can achieve more headspeed on Calibers (1868 or 1770) leaning engines and burn 30% nitro but, at what cost for engine life and wallet?

Right now, I'm more interested to be skilled in sticker banger 3D type flying, I own two Raptors and they can do with some limitations (they need to upgrade plastic heads to metal), I fly a Trex 600 and is an incredible machine, I fly my Caliber 5 and... well is like ad says “the perfect training 50 heli of the year“ and sport flying too, but no more.

I understand Kyosho target are seniors, sport/light 3D pilots and newbies, I loved my Caliber 5, personally I belive it has a winner frame design and nice quality materials (the monocoque rear frame give almost no resistance to air in autos and tumbles) but was limited when pilot demands power, efficient ratio and faster collective and ciclyc response, yep my Caliber feels sticky and slow when compared to an exact configuration on a Raptor 50 except that Raptor has the non hyper power plant.

No more Kyoshos for me for now, I sell my spare a month ago and right now I'm try to sell my ARF. Let's see if kyosho could bring with an ultimate machine, not the same one with upgrades.

Flying pigs 8,000 feet above Sea level
03-14-2008 12:02 AM
 
 
dkshema
rrProfessor
Location: Cedar Rapids, IA

Quote 
Of course we can achieve more headspeed on Calibers (1868 or 1770) leaning engines and burn 30% nitro but, at what cost for engine life and wallet?

My Caliber 30s running an OS 37, and my Caliber 5 with the 8.97:1 gearing and a YS50 have been consistently tached at 2000 - 2100 rpm on separate days, separate occasions, separate tachs and operators. I'm not running overly lean, and have been flying the same 15% Sig Champion heli fuel for years. I don't roast motors, but when I had the OS in my C5, had the predictable rear bearing replacement. I haven't seen any decrease in engine life in my C5 as compared to my EVO.

We can argue headspeed all day long, but in the end, the heli performs pretty darn well. I enjoy my C5 every bit as much as my EVO 50 with its 8.5 ratio.

The C5 may not be your cup of tea, but everyone is different.

I'm flying at about 850 feet altitude, Alien is flying something on the order of 8000 feet. Believe me, that extra 3000 feet altitude is nothing to sneeze at when it comes to performance.

-----

* Making the World a Better Place -- One Helicopter at a time! *

Dave
03-14-2008 02:15 AM
 
 
heli-cuzz
Veteran
Location: Pittston, Pa. USA

aliensil,
I've flown all the above you mentioned including the EVO that dave mentioned. They don't feel any better or worse than the Caliber5.
I don't hate Raptor or Trex. I love all helis.

Quote 
Caliber feels sticky and slow when compared to an exact configuration on a Raptor 50 except that Raptor has the non hyper power plant

That's how I felt when flying my friend's Raptor with a Hyper. It didn't seem as smooth as the C-5.


Answer this one question, can you outfly the Caliber5?

Life Rotors On!!!
03-17-2008 12:19 PM
 
 
aliensil
Senior Heliman
Location: Laredo Tx

Helicuzz,

I can fly my Caliber 5 at 1,800 rpm and even a little more, I don't question the smooth of kyosho but my Raptors are a lot more crisp and fast, fand the precise fast TREX 600N. Is just that these 200 extra rpm on lower ratios are always there.

Caliber 9.1:1 or 9.1:6 ratios gives more torque at 1,700-1,800 speed and bog less than raptors do but, is slow on cyclics and collective, I use similar setups for both, maybe Mexico city heigh (or any city as high sea level)are more crucial to this interactions headspped-power-nitro content-cyclic.

I'm decided to find a good machinist shop and work on a 13 teeth counter to increase the ratio, until that, my last Caliber are sitting down at LHS for sale (for two months now and nobody wants to buy, funny thing).

Flying pigs 8,000 feet above Sea level
03-17-2008 03:33 PM
 
 
heli-cuzz
Veteran
Location: Pittston, Pa. USA

Well, sorry to hear your straying away from the Caliber.
Just so you know, I constantly run mine at 1950 with the Hyper. I have three hypers now and all run beautiful but one because its brand new so it hasn't been started yet. Anyway, I never run to lean and never have roasted an engine running at 1950 headspeed. I do believe it brings engine RPM a little above what the manual says, but I have no problems and have averaged a little over 40 gallons a year for the past two years. I check the compression often to give me notice when its time to replace the ring. I'll leave the old piston and sleeve unless it needs changing. Its been about twenty gallons when its time to change out the ring and every 7 to 10 gallons on the rear crank bearing.
You want to speed up the cyclic roll and flip rate. Change the stock pitch link position to the outer hole and that'll make it snappy.

Life Rotors On!!!
03-17-2008 10:27 PM
 
 
aliensil
Senior Heliman
Location: Laredo Tx

Bryan

I do all with the Caliber, use both eccpm and ccpm. upgrade pinion, washout, counter, lighter paddles, stock paddles w/o weights, better CF blades, use outer holes for cyclic, all carburation and engine setups I can found, tached headspeed with a min aircraft tach, etc. even use 30% nitro and use an MP2 pipe designed for 8.5 to 9 ratios, I don't say Caliber 5 is a bad machine, I'd love as much as my old Caliber 30, but times change for more interesting and agresive flying styles and Kyosho are not in that game. My Caliber is simply an alegant and smooth sport heli, nice design, great quality, super price, smooth, not crisp,thats all and I think is a shame.

If we do math homework as manual says we always have 200-250 less rpm's than any 8.5 stock heli ratios foreverever.

I hope this comments help kyosho design guys work on a better heli or a much capable one. By the way, have you seen the RJX extreme 50 or the new Trex 700? simply beautiful.

Flying pigs 8,000 feet above Sea level
03-18-2008 01:17 AM
 
 
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Kyosho Caliber 30 & 60 - Concept - Nexus > Caliber 5 ratio
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