What size blades for Raptor 90 3D?

[vandelescrow]

For Main blades I've been told 690 vs 710. What say you?
What about tail blades? Ive read reviews that the kit comes with plastic and dont hold to well so you should upgrade to carbon fiber. I'm not finding anywhere what size they are (I dont have the heli yet so I cant measure them). Per a few sites they say a 90 should have 105mm but due to the main rotor being below the flybar on a Raptor, are these to big?

[Kinger]

You can use 710 main blades and 105 tails without any worry. As for 710's vs. 690's......I suppose some of it depends on your collective management, but it seems like most folks prefer the feel of the 710's.

[Seeker]

Hey Kinger...

Stealing the thread a second... was that you I saw in the R/C hobbies program from IRCHA (I think it was last years)? I know Mallery (I'm sure I hosed that spelling, sorry Mal) was in it.

It happened to get recorded the other day on my DVR.

[Kinger]

Not sure, I don't think I've ever seen the show. If it showed a REALLY good pilot, then I'm guessing it wasn't me :) Could be Jared Granzow though.

[Laurens]

690 are harder to bog down then 710. I run 710 but they don't bog down that much. I even ran 110mm taiblades without problems.

[mrhook]

Also
K & B make a 102mm plastic tail blade that is said to hold better and give better tail control. Also they are cheap.

[iher]

Its a balance, a game of compensating what everything else in the heli is doing.

1- if MAIN BLADES are larger ( e.g. 710´s) then:

-Larger rotor disk
-more mass
-less RPMS needed( blade tips travel @ higher speed = more lift)
-more blade drag=more energy needed to speed up
-more energy to be stored in autos= more time needed to speed blades up
but more energy available at landing
-more heli overall weigh and mass to move around = less agile 3D
-the greater the mass, the greater the main disk gyroscopic effect =the flybar
system has to compensate more ( if you want the same effect than smaller main
blades, then flybar paddles must be larger and/or lighter)

so, if you go with 710 you need more teeth in the main gear
if you want to reduce the blade size to 690 or 680 you should reduce the number of teeth.

Another factor: you can play with gears and change the engine pinion /main gear ratio, to use your engine at higher or lower rpms. This will give you the option of using longer or shorter tail blades.

2- if TAIL blades are larger,
- faster response
- more dificult for the gyro /servo to maintain center and more sensitive and nervous feel
- less precision ( you will have to reduce gain and ajust servo horn to maximize resolution
- a little play in the control chain( servo/ ball link/ rod....blade holder/ blade) will become a
bigger problem= the gyro/servo will have a hard time keeping a set position.....and starts
hunting near center.

if that is not enough .....at what altitude do you fly?
I fly at 9000 feet ( mexico city) so a 30% loss of air density does matter.
In my case I have to consider extra lift, so I increased rotor Rpms and increased blade size: 1900 Rpm with 710´s
Because of this loss of density, oxygen is also compromised. So I have to run the engine at higher rpms too, and use 30% nitro.
I honestly would prefer using smaller blades, but the only option would be more headspeed. but i´m not comfortable pushing a Raptor 90 SE over 2000rpms . Even with metal blade grips.

I hope this helps

[DebianDog]

I like 710's on my 90 sized because it "moves out" but Alan Szabo like 690's as he said it rolls faster and it is easier to maintain head speed.

[iher]

Debian dog.
I followed your thread/discussion about blinging trucks versus buying a heli.........that was a heated debate between you ( the "minivan guy") and the other truck lovers

[DebianDog]

Debian dog.
I followed your thread/discussion about blinging trucks versus buying a heli.........that was a heated debate between you ( the "minivan guy") and the other truck lovers

Yeah I was a bit outta line but getting a Heli is ALWAYS a better option Truck or not ;)