TheBum

How about the meaning of the KV rating of brushless motors? It could either be its own item or added to the definition of Brushless Motor. It took me a bit of searching to find that it translates to RPM per volt applied. Being an EE by education (I'm a software engineer by trade), I immediately mistakenly translated it to kilovolt and wondered how you could generate 3000 kilovolts with a 11.1V battery and have enough current to drive a motor.

xuzme720

dude! you figure that out and you'll have solved ALL our power issues!

brnyrbbl

Brushless motor Kv has been added to the definitions.

HX3D014

More info on why the stall would be Relevant.

I wouldn't confuse people on Feathering. it is Teetering. or flapping . If you liken it to an Airplane. It would be similar to Dihedral.

you may want to Include the point of Cyclic action to Cause Symmetry (Relatively or Controlled) Flapping blades and Delta offset are a means of dampening un-commanded disk actions.

I get confused when I read this. Are you trying to describe the Feathering Axis of the Blade (PITCH) or the Teetering action ??

Again you mention Feathering on this one. Are you referring to the Teetering action. or an Action of Blade flap on an axis inline with the chord line. if the later. then they are independent.

cuc tu

Unfortunately, there is one more term for beginner heli terms. One that nobody likes, but will all come to know.

Crash--Unintentional contact with the ground or other object that usually results in a financial expendature.

brnyrbbl

I didn't come up with the terms or descriptions. They were compiled from various heli sites and were written by experts, instructors or companies.

brnyrbbl

Feathering Shaft
A rod which helps support the rotor blades and give them more ridged strength. A flapping head has two feathering shafts (one for each blade) and a sea-saw head has one feathering shaft (running the span of the head)
** The feathering shaft is what's being described. It is exactly as the description says, a one piece ridgied rod that connects the 2 blades together. This is not a description of "feathering". Again, I did not write these definitions as the previous post explains.

Flapping
A type of rotor head where the two rotor blades are not connected directly through the feathering shaft (a thick wire), each blade can move somewhat independently of the other resulting in smoother control of the helicopter and the to some degree the feel of a .60 size heli.
**Flapping
A type of rotor head where the two rotor blades are not connected directly through the feathering shaft (a thick wire), each blade can move somewhat independently of the other resulting in smoother control of the helicopter and the to some degree the feel of a .60 size heli.

Again, this refers to the feathering shaft and NOT feathering. There is a difference between the two. Later in the the description it states flapping style heads have somewhat independent blades. This has nothing to do with teetering action or the see-saw. Read the post above as these definitions were not created by me.

brnyrbbl

See-Saw Head
A form of rotor head where the two rotor blades are "connected" through a feathering shaft (thick wire) so that when one pitches up the other pitches down. This makes for a more stable helicopter an a simpler design, but does not hand le as well as a flapping head type.
Actually, it wouldn't be similar to dihedral. If the rotor blades were allowed to travel creating a concave rotor disk where the blades pitched up equally from the center to the tip then it would be similar to dihedral. Again, this was not a description for feathering OR the feathering shaft. It was for the see-saw and it simply included the feathering shaft to demonstrate how the see-saw head works.

HX3D014

correct. and so it is not feathering. the point is to look at one blade alone. and when it alone goes up. the direction is similar to the effect of adding dihedral. (Ignore the opposit blade for now) and so this example was given to indicate that there was no feathering of the Pitch. but the whole blade in the SAME way a wing is moved when adding anhedral or dihedral. I am fully aware of what is different. but as that blade Flaps or teeters up . it is moveing the same way a wing would if you added Dihedral.

Feathering is just for Pitch change.
teter or flap.
teeter has one hinge central to the Shaft axis. and Flaping has one hinge per blade.

brnyrbbl

Yes, that's correct. The way you described it in the above post is perfect!

HX3D014

Retreating blade stall is not when the heli goes to fast to cause not enough Relative airflow on the retreating side. it is
when the blade is at the retreating side, it is also at a Higher angle of attact (Because the comand from the swash is to get it High at the rear) and due to the AoA being to high. the blade stalls. <usualy at the tip> the area of the blade that is receiving a reverse flow is not stalled. it is just in reverse flow.

check out this one
you may want to ignore the red bit. it is hard for Pilots to understand and is commonly debated. but pictures are available. just cant find one at the moment. OK Found one.

Bob M

Back to page 1 again!

Bob M

Back to the top!!

theecoop

How would one recover from a Retreating blade stall?

HX3D014

mostly. you will get warning signs of it about to happen.

But if you push into it. and it happens.

1st thing you must do is reduce collective
2ns thing is land and have a stiff drink and think about why it happened. IE why did you go there. (It is usually only going to happen if you exceed design limitations. IE VNE or VNE @ given Weight and Alt combination.)

JacksonH

Could you explain what the different size designations mean. I understand that a T-rex 450 is smaller than a 600, but what do those numbers mean? What about a Raptor 50? What does that mean?

Thanks for clearing up a lot of terms.

Jackson Hawk

ricknew

This is great, Thanks! Lots of good info. I don't know what a stickie is but I'm all for it...

Asperamanca

From a beginner's viewpoint (mine), the description of the different sizes seems to be missing.

Again, I can't post links due to some forum rule, but you can find a description on www[DOT]rcheliwiki.com/Helicopter_sizes

Osiris

Great job, must hav taken ages, keep it up! very helpful

HeliG

Jackson,
Unfortunately, there isn't really accurate info that comes with numbers. Originally, the numbers related to engine size but with the electric helis moving in, those numbers have gone away. A 450 doesn't really tell you much except that it is smaller than a 600.

HeliG

Here is the info from http://www.rcheliwiki.com/Helicopter_sizes that Asperamanca was talking about but as I stated before, the sizes don't correspond to anything in particular anymore.

Sub-micro (<100g, <20cm rotor diameter)
Extremely small helicopters, often coaxial. Low total energy makes them suitable for flying indoors.
Micro (<500g, <50cm rotor diameter)
Small helicopters such as 350-sized electric helicopters.
Miniature (<1kg, <80cm rotor diameter)
400 - 450 sized electric helicopters, can be flow inside in large open spaces with care.
Small (<2kg, <100cm rotor diameter)
500 sized electric helicopters.
Normal (<4kg, <150cm rotor diameter)
30 and 50 sized nitro helicopters, 600-sized electric helicopters.
Large (<6kg, <200cm rotor diameter)
90 sized nitro helicopters

Unstoppable RC Flyer

This is wonderful, Thanks! I don't know what a stickie is but sure stick it for the fun of it......

Crash9

that's cool this is a sticky. Aaron (aka brnyrbbl) would be glad that he left this behind as he passed away back in Aug 2010 ...Hope it stays up a long time and many add to it .

whirlibird

Great Info !

flyer

this is super helpful! thanks!