The non-issue (to me) of engine RPM's

SuperDave Thu Oct 06, 2011 10:47 am

Consider a multi-speed bicycle. What is the importance of crank RPM's to bicycle performance?

Then apply that logic to engine RPM to engine performance.

Hmmmmmmmm..................

microflitedude Thu Oct 06, 2011 10:56 am

My head hurts. RPMs can be everything, yet, they can't.

SuperDave Thu Oct 06, 2011 11:04 am

microflitedude wrote:My head hurts. RPMs can be everything, yet, they can't.

dude:

I believe my bicycle analogy to be a good one and not all that difficult to grasp given some thought.

A bicycle rider who thinks that crank PM's are important soon finds himself exhausted without having gone very far.

Why?

PV Pilot Thu Oct 06, 2011 11:10 am

[quote="SuperDave"]

microflitedude wrote:A bicycle rider who thinks that crank PM's are important soon finds himself exhausted without having gone very far.

Why?

Because he didn't eat his Wheaties.

SuperDave Thu Oct 06, 2011 11:22 am

[/quote]

Because he didn't eat his Wheaties.[/quote]

OK wise guy, assume he HAD eaten his "Wheaties". Wink

Answer my question.

PV Pilot Thu Oct 06, 2011 12:04 pm

Gearing, or gear ratios.

SuperDave Thu Oct 06, 2011 12:36 pm

PV Pilot wrote:Gearing, or gear ratios.

Close buy not quite.

The purpose of which being?

SuperDave Thu Oct 06, 2011 12:37 pm

SuperDave wrote:
PV Pilot wrote:Gearing, or gear ratios.

Close but not quite.

The purpose of which being?

nitroairplane Thu Oct 06, 2011 12:47 pm

SuperDave wrote:Consider a multi-speed bicycle. What is the importance of crank RPM's to bicycle performance?

Then apply that logic to engine RPM to engine performance.

Hmmmmmmmm..................

the rpm is always important but if you are in say gear 1 doing 100 rpm at the crank you will be going slowly but then if you do 100 rpm in gear 6 you will really be moving.
What i meant in the thread about props with my comment on the nano making more thrust than a tee dee .010
let me put that in terms of bikes..........
lets say the first person is a tee dee .010 and he is doing 100 rpm on the cranks in gear 4
when compared with nano turning the cranks at 170 rpm in the same gear who will be going faster?
Nano will be.
That is what i originally tried say.

PV Pilot Thu Oct 06, 2011 12:54 pm

SuperDave wrote:
PV Pilot wrote:Gearing, or gear ratios.

Close buy not quite.

The purpose of which being?

The torque applied to random, unknown ratios determines your unknown engine performance.

SuperDave Thu Oct 06, 2011 1:24 pm

Good job, PV.

Torque is often touted but rarely understood. Torque is an engine's (or motor's) abilty to do work. Torque is measure in foot-pounds/inches or the metric equivilents

It's parallel in electricity is amperage. It is very comonly is is assumed that VOLTAGE does the "work" which is simply NOT true.

Experiement and see but don't blame if you make the wrong experiement. Affraid or WOW!

"Stupid hurts" - John "The Duke" Wayne

nitroairplane Thu Oct 06, 2011 1:43 pm

SuperDave wrote:Good job, PV.

Torque is often touted but rarely understood. Torque is an engine's (or motor's) abilty to do work. Torque is measure in foot-pounds/inches or the metric equivilents

It's parallel in electricity is amperage. It is very comonly is is assumed that VOLTAGE does the "work" which is simply NOT true.

Experiement and see but don't blame if you make the wrong experiement.

"Stupid hurts" - John "The Duke" Wayne

wrong experiment Blow up Mad!

SuperDave Thu Oct 06, 2011 2:52 pm

nitroairplane wrote:[quote="SuperDave"

wrong experiment

nitro:

"Stupidity is it's own reward" from the collected "Timeless Widsom's" of Super Dave

lol!

nitroairplane Thu Oct 06, 2011 3:46 pm

SuperDave wrote:
nitroairplane wrote:[quote="SuperDave"

wrong experiment

nitro:

"Stupidity is it's own reward" from the collected "Timeless Widsom's" of Super Dave

yep when i was 13 my friend decided to poor white spirits on a barbeque he singed his eyebrows it was soooo funny but stupid.

shell shock Thu Oct 06, 2011 4:10 pm

"this one time, my buddy Keith tried to deep fry a turkey... 3rd degree burns on 90% of his body" - Ellis
And this is why stupid hurts.
Back on topic, I agree, you could have all the rpm's your engine could handle, but its all moot if it does not have the torque to pull it. In fact, this is how i burned my bikes engine.

nitroairplane Thu Oct 06, 2011 4:14 pm

shell shock wrote:"this one time, my buddy Keith tried to deep fry a turkey... 3rd degree burns on 90% of his body" - Ellis
And this is why stupid hurts.
Back on topic, I agree, you could have all the rpm's your engine could handle, but its all moot if it does not have the torque to pull it. In fact, this is how i burned my bikes engine.

WOW is that a real story?

microflitedude Thu Oct 06, 2011 4:16 pm

nitroairplane wrote:
shell shock wrote:"this one time, my buddy Keith tried to deep fry a turkey... 3rd degree burns on 90% of his body" - Ellis
And this is why stupid hurts.
Back on topic, I agree, you could have all the rpm's your engine could handle, but its all moot if it does not have the torque to pull it. In fact, this is how i burned my bikes engine.

WOW is that a real story?

Doesn't surprise me. Us stupid Americans will do anything. lol!

nitroairplane Thu Oct 06, 2011 4:17 pm

microflitedude wrote:
nitroairplane wrote:
shell shock wrote:"this one time, my buddy Keith tried to deep fry a turkey... 3rd degree burns on 90% of his body" - Ellis
And this is why stupid hurts.
Back on topic, I agree, you could have all the rpm's your engine could handle, but its all moot if it does not have the torque to pull it. In fact, this is how i burned my bikes engine.

WOW is that a real story?

Doesn't surprise me. Us stupid Americans will do anything.

hey hey we have all done our fair share of stupid [bleep].

shell shock Thu Oct 06, 2011 4:20 pm

he he he, i might be showing my age here, but no, its from a video game characters banter as you and your group go through a zombie apocalypse. he has tons of Keith stories. And yes, im sure we have ALL done of fair share of stupid stuff...

nitroairplane Thu Oct 06, 2011 4:43 pm

shell shock wrote:he he he, i might be showing my age here, but no, its from a video game characters banter as you and your group go through a zombie apocalypse. he has tons of Keith stories. And yes, im sure we have ALL done of fair share of stupid stuff...

You play cod?

shell shock Thu Oct 06, 2011 4:46 pm

Nope. I try to stick to valve games (tf2 counter strike, half life and such)

also, on the note of rpms, was a transmission or clutch ever developed for these engines?

nitroairplane Thu Oct 06, 2011 4:54 pm

shell shock wrote:Nope. I try to stick to valve games (tf2 counter strike, half life and such)

also, on the note of rpms, was a transmission or clutch ever developed for these engines?

I don't think for cox engines but
I have a little
Nitro rc car with a 2 speed smtransmition the engines is a toki .05 so very close to .049 the old cox cars had a sort of engage/dis-engage Lever a little likens clutch.

**Admin** Thu Oct 06, 2011 5:01 pm

I think the closest thing you will find to a transmission and clutch is the RC Jerobee McLaren MK 8B with the Cox engine and the Sea Bee boat. http://www.mh-aerotools.de/airfoils/cox_models.htm

nitroairplane Thu Oct 06, 2011 5:20 pm

Admin wrote:I think the closest thing you will find to a transmission and clutch is the RC Jerobee McLaren MK 8B with the Cox engine and the Sea Bee boat. http://www.mh-aerotools.de/airfoils/cox_models.htm

Actually a guy on YouTube called fimakaro made a 2 speed gear box for his pee wee 020 and put it on an rc car.

SuperDave Thu Oct 06, 2011 6:06 pm

I would remind you that any gearbox or transmission takes it's toll in torque lost the higher the RPM ratios ergo "lugging" occurs and efficiency is lost.

Physics 101

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