Cc or hp

[Eddy_t]

So if you were on piece work felling in a wood all day and you had 4.5hp saw weighing 5kg and a 4.5hp saw weighing 10kg you would not care which one you use ?

 

 

Yes, the lighter saw is more comfortable. But just by that question of piece work you've opened it up to more. Is it hard or softwood? Large or small diameter? Large hardwoods would require high torque and larger displacement, small softwoods would require a higher speed, but less power and torque.

[Stubby]

Yes, the lighter saw is more comfortable. But just by that question of piece work you've opened it up to more. Is it hard or softwood? Large or small diameter? Large hardwoods would require high torque and larger displacement, small softwoods would require a higher speed, but less power and torque.

 

But I said the same displacement . You got a choice one or the other , both same displacement different weights . What I am saying is I think power to weight ratio is important . just me .

[Eddy_t]

But I said the same displacement . You got a choice one or the other , both same displacement different weights . What I am saying is I think power to weight ratio is important . just me .

 

 

No, you said 4.5hp, which could be a 560xp or an old 041 super (these are saws close to the weights you gave), the 560 pulls a smaller bar and goes like stink, the 041s pulls almost 30" bars.

[wisecobandit]

Torque is only developed in response to load. A blunt chain imposes no load as it merely spins. Just like a Landy with bald tyres.

It just spins, developing high speed but no torque.

Im with Barry on this 1.

There are atleast 3 different hp measurements and different manufactuers use different ones so what may seem the same on paper feels different in hand.

 

As for torque like Barry says and I think the best way of putting it is put a car and a 4x4 with equivalent hp, cc and weight at the bottom of a big hill both towing a 3 1/2 ton trailer and see what gets to the top of the hill first.

Being dramatic its a bit like comparing your average 17 1/2 tonne 250hp lorry to a Subaru impreza turbo (250hp) towing a 16 tonne load.

Power is developed in very different ways.

 

Its torque that pulls a load not hp or cc. You can prob get remote control nitro cars and planes 6-7hp easily but doesn't mean to say they could pull a chainsaw chain in 12" of wood for that very reason.

[wyk]

Horesepower and torque curves cross at 5240 RPM...or so..

 

Assuming factory tuning, the saw that has 5 HP at 9K RPM has much more low RPM torque than the saw that has 5HP at 11,000 RPM.

[geoff]

HP = Torque x RPM ÷ 5252

[Stubby]

No, you said 4.5hp, which could be a 560xp or an old 041 super (these are saws close to the weights you gave), the 560 pulls a smaller bar and goes like stink, the 041s pulls almost 30" bars.

 

You are right , I did say 4.5 hp. Apologies

[Big Beech]

All I know is, if my 090 can't cut through it its one hell of a tree

 

Stubby, what's the breeding of your springer?

[TimberCutterDartmoor]

"No substitute for cubic inches". Splitting hairs when it comes to chainsaws tho imo. My 59cc brand a is torquier than my 61.5cc brand b.

[Stubby]

"No substitute for cubic inches". Splitting hairs when it comes to chainsaws tho imo. My 59cc brand a is torquier than my 61.5cc brand b.

 

Do you remember that film with Tom Cruise when he was young ? His parents went away and he had a mega party in the house culminating in thrashing and trashing his Dads Porsche . After the carnage he said " Porsche , there is no substitute ! "