RCCA uses a propeller to dyno?

[ducati777]

I keep seeing references to RCCA's propeller dyno vs RCX intertial dyno. Is this true? I was under the impression they both used inertial, but RCCA uses a stand with a prop on it to break in new motors....

In my opinion a prop doesn't seem like a very good way to measure power, so I'm pretty curious if they went this route?

[ayk_driver]

the prop puts a load on the engine or else you wouldnt get a good reading... like with real engine dyno's... they put a load on the flywheel or else you would get wrong/bad numbers...

[ducati777]

I know all about that action, but a prop isn't a good representation of the load the motor will see in a car.

For example, lets say you use a really peaky motor, one that makes all its power way up in the rpms... If you use too big of a prop, it may never hit that high rpm, and thus never hit its own powerband. This is pretty common with high end .049 airplane motors, where a smaller prop developes more power than a standard .049 sized prop.

Anyway inertial dynos make the motor spin up a heavy disc, and measure how quickly that happens. Even if you're using a peaky motor, it'll get a chance to make it to high rpm, unlike with a prop.

Also, you can use the same weight for big blocks and little motors alike, again with a prop you'd need to use a prop that suited the motor, making comparisons between motors difficult to say the least.

So.... can anyone confirm that RCCA uses a prop? Or did someone see their break-in stand in a picture and assumed it was their dyno? It doesn't take much to get a rumor going on these boards.

[doesgo]

It's XRC (Xtreme R/C Cars) magazine that created and uses the inertia dyno, not RCX. RCX is the name of the big R/C show in Anaheim next month! :)

[ducati777]

It's XRC (Xtreme R/C Cars) magazine that created and uses the inertia dyno, not RCX. RCX is the name of the big R/C show in Anaheim next month! :)

Uhhh yea, I totally knew that. yep. Just a typo I swear. :o

[BrushlessHawaii]

Uhhh yea, I totally knew that. yep. Just a typo I swear. :o
DUNCE. LOL :D

[Grizzbob]

I know all about that action, but a prop isn't a good representation of the load the motor will see in a car.

For example, lets say you use a really peaky motor, one that makes all its power way up in the rpms... If you use too big of a prop, it may never hit that high rpm, and thus never hit its own powerband. This is pretty common with high end .049 airplane motors, where a smaller prop developes more power than a standard .049 sized prop.

Anyway inertial dynos make the motor spin up a heavy disc, and measure how quickly that happens. Even if you're using a peaky motor, it'll get a chance to make it to high rpm, unlike with a prop.

Also, you can use the same weight for big blocks and little motors alike, again with a prop you'd need to use a prop that suited the motor, making comparisons between motors difficult to say the least.

So.... can anyone confirm that RCCA uses a prop? Or did someone see their break-in stand in a picture and assumed it was their dyno? It doesn't take much to get a rumor going on these boards.
Actually, I believe that RCCA uses the same Robitronic dyno that I have, & it uses a flywheel on the motor's output shaft to provide the load(& no, it may not be prefect, but it is consistent, it'll put the exact same load on any motor, anytime).... :cool:

[-=ADA$=-]

http://img247.echo.cx/img247/6263/dynoedited5ip.th.jpg (http://img247.echo.cx/my.php?image=dynoedited5ip.jpg)
Heres a link to scan i made of RCN, thats why i believe they dont use propeller

[ducati777]

http://img247.echo.cx/img247/6263/dynoedited5ip.th.jpg (http://img247.echo.cx/my.php?image=dynoedited5ip.jpg)
Heres a link to scan i made of RCN, thats why i believe they dont use propeller


Nice! See I thought the propellar was for break in! They have another stand that looks similar to that one with a prop and shroud on it. They run the motor at WOT with a prop on it.. there was some article on it a while back.

Thats a tricky dyno right there. Its turning what looks like a big generator. The software likely measures volts and current off of it to calculate torque and rpm. Pretty slick setup.

All in all an inertial dyno with a flywheel is probably the best design. A flywheel ought to be super consistent.

Anyway thanks for the pic Ada.