gearing.

[abyiss]

hello everyone reading this post.!

im building a v-max @ the mo,i looking @ diferant gearing..im using 91/11
do i have any other options,?

i read the manual and i carnt make head or tail witch way too go..mmm

say i went 12/91.what gains would i get?.or even 11/94

would someone explain.what gains i will get from changing gearing?.

[Thomas]

If it helps, that was the combination I had on my Raptor 90, and seem to be the favoured option.

[Steve]

It depends on your engine and the head speed you require.

If for arguments sake, your engine produces it's peak power output at say 18,000 rpm, then option one will give you a head speed of 18000 x (12/91) = 2374 rpm. Option two would give you a head speed of 18000 x (11/94) = 2106 rpm.

So, lets say you went for option two, then when you set your head speed on your governor to 2106 rpm, then you can be confident that you are riding the peak of the power curve from the engine, thereby getting the absolute most out of it.

[Kwickkwack]

hello everyone reading this post.!

im building a v-max @ the mo,i looking @ diferant gearing..im using 91/11
do i have any other options,?

i read the manual and i carnt make head or tail witch way too go..mmm

say i went 12/91.what gains would i get?.or even 11/94

would someone explain.what gains i will get from changing gearing?.

11-91 = ratio of 8.272 for a head speed of say 2000rpm, engine is at 16544
12-91 = ratio of 7.583 for a head speed of say 2000rpm, engine is at 15166
11-94 = ratio of 8.545 for a head speed of say 2000rpm, engine is at 17900

I guess it depends at what revs the engine makes its max power and torque, you would want the have the engine running as close to that as possible to utilise the power.

Well I think so, but I am sure somebody will have a much better answer.



Edit. While I was writing the manager beat me to it lol

[Steve]

All IC engines, the one in your car included, produce their peak power at a given rpm, and if you plot a graph of power against revs then it looks like a 'n', so if you go over the optimum rpm then you loose power, and if you are under it then you also loose power.

So, in an ideal world, you should look to be running your engine at the top of the rpm-power curve, and the optimal rpm for for peak power will br given in the engine's specs - usually about 18,000 for OS engines.

[mattie-lodge]

All IC engines, the one in your car included, produce their peak power at a given rpm, and if you plot a graph of power against revs then it looks like a 'n', so if you go over the optimum rpm then you loose power, and if you are under it then you also loose power.

So, in an ideal world, you should look to be running your engine at the top of the rpm-power curve, and the optimal rpm for for peak power will br given in the engine's specs - usually about 18,000 for OS engines.

The 90 size engines power band is lower then the 50's

15500 for an OS 90 SZH I think

Cheers

Matt

[jamiesawyer28041978]

Sorry for gate crashing but I was very interested in this tread , where would you get the info on yous engine rpm and data , my engine is a tt 50 pro with no instructions, second hand but was only bench broken before I bought it .Would 18000 rpm be a good guess for it .

[Steve]

OS 32, 37 and 50s are all specced at 18,000 rpm I think.

[abyiss]

nice0ne every-one.

im using a os91 sz-h with mp5.

just carnt get my head around gearing...i think i may stick with 11/91.*(as this its like a rocket).
but im looking to go for more power rather than speed.

[Nutz]

As per link for 91 C-spec
http://www.osengines.com/engines/osmg1982.html
Peak power is 15,000RPM

[abyiss]

this one dude..

http://www.osengines.com/engines/osmg1983.html


im runing my revloc @ :

mode 1 14500(hovering and lasy flying

mode 2 15500(manic stunt flying)
and using 11/91 .

so im kinda wonta try changing the engine.firstly to bring engine noise down..but still have its rocket power.lol

[Steve]

If your engine produces it's peak power output at say 15,000 rpm, then option one will give you a head speed of 15000 x (12/91) = 1978 rpm. Option two would give you a head speed of 15000 x (11/94) = 1755 rpm.

So, depending on your gearing option, say you went for option one, then you should be aiming for a governed head speed of 1978 rpm.

[Steve]

Basically, option one is aimed at 3D flyers, and option two is aimed at F3C flyers. Alternatively, option one is aimed at OS engines, and option two is aimed at YS engines.

[abyiss]

kinda get what your saying..
im looking for a head speed around 1900 .in stunt mode.
.
maybe i should stick with 11/91..@ 15500rpm.?

[Steve]

kinda get what your saying..
im looking for a head speed around 1900 .in stunt mode.
.
maybe i should stick with 11/91..@ 15500rpm.?

Lol

According to your original post, the options are 12/91 or 11/94.

Where did 11/91 come from?