Blades for Speed Flying

[RJ]

For comments related to blades for speed flying.

[RJ]

Originally Posted by joliecoeur13

Would good FB blade be good for speed ?
I'm running some Radix V1 or I think they are FB version , so far the best blades I had on that machine...

Didn't want to get off topic in the Speed X-Blades thread.

It's not so much how a blade is labeled (FB vs FBL) which determines whether it is good for speed, but rather the properties of the blade. Some blades which came out in the flybar era before FBL was popular are still good FBL blades and can be good for speed flying (Rotortech Angled-Tip blades used by Robert Sixt at the Pöting-Speed Cup). But of course now we are seeing blades designed especially for speed flying, so it will be interesting to see what comes up.

The Radix FBL 710mm blades are good for speed, also the Radix V2 710mm (also FBL), which is what was run on SFR1 for the 2012 IRCHA Speed Cup. The Radix FBL and V2 have the chordwise CG in line with the bolt hole. The flybar version, Radix 710mm (Original) has a more rearward chordwise CG, so it will tend to lead and is less desirable for speed flying.

Left image is Radix FBL, middle is Radix V2 (FBL), right is Radix Original (flybar)

[NevErSn0w]

Awesome! Thanks for the info!

Sent from my GT-I9305 using Tapatalk

[joliecoeur13]

thanks for that , do you know the weight of the Radix V2 ? my FB version is 180gr /each

[mkovalcson]

Originally Posted by joliecoeur13

thanks for that , do you know the weight of the Radix V2 ? my FB version is 180gr /each

Mine are generally right around 200grams each +/- a few grams.


I've got one here that is 198.85g

[joliecoeur13]

Originally Posted by mkovalcson

Mine are generally right around 200grams each +/- a few grams.


I've got one here that is 198.85g

thanks,
I read the top post saying no more then 225Gr to reduce wear on system, but it's not like I'm racing ! so I'm sure a couple packs a week wont matter ?
thinking of getting some SG 720's , they have a thinner chord 60mm I think ..and about 220gr.

[mkovalcson]

Originally Posted by joliecoeur13

thanks,
I read the top post saying no more then 225Gr to reduce wear on system, but it's not like I'm racing ! so I'm sure a couple packs a week wont matter ?
thinking of getting some SG 720's , they have a thinner chord 60mm I think ...

I'm not pushing my TDR past 2000 rpm, but the heavy Speed blades are only going on my Banshee which is built for this, and I'll eventually try them out at 2300 rpm.

[firemedic295]

I had good results with V2 on my speed TDRs. If you are planning on pushing 2500 rpm and 15 or more of pitch you will have to be very aggressive with maintainance.

[RJ]

Originally Posted by joliecoeur13

thanks for that , do you know the weight of the Radix V2 ? my FB version is 180gr /each

The Radix blades that I have measured (with a sample size of one pair):
Radix Original (FB) 710mm blade = 185.9g
Radix FBL (V1) 710mm blade = 197.2g
Radix V2 (FBL) 710mm blade = 202.0g

Note that the Radix FBL (V1) and the Radix V2 (FBL) blades appear to be from the same mold and are essentially the same weight, so the overall weight doesn't tell the whole story with regard to flight characteristics. The difference is in the position of the CGs, with the Radix FBL spanwise CG being more outward toward the tip, and the Radix V2 being more inward.

The spanwise CG is also an important factor because the equation for centrifugal force has a radius term, so for equal weights, the blade that has a more outward spanwise CG is generating more centrifugal force and more torture on your thrust bearings. The heavier or more outward CG blades tend to be more stable in FFF, but we are limited by the thrust loads, and so we have to balance the blade weight, CG position, RPM, and maximum pitch among other things.

[RJ]

I think it would be helpful in our study of blades for speed flying if we started to try to quantify the characteristics of the blades we feel work well and maybe those that don't work so well. Some characteristics that I can think of include the following:

Blade name:
Blade length:
Root thickness:
Overall blade weight:
Chord in middle:
Thickness (mm/%) in middle:
Chord at root (if not constant):
Thickness (mm/%) at root (if not constant):
Chord at tip (if not constant):
Thickness (mm/%) at tip (if not constant):
Distance of bolt hole from leading edge:
Distance of chordwise CG from leading edge:
Distance of spanwise CG from bolt hole:
Description:
Comments:

It would be great if everyone can add to the databank with info on blades they have. Especially on blades that have been tried for speed flying.

[RJ]

Okay, I'll start with the data I have (CGs determined with Koll Rotor Pro balancer).


Blade name: Radix Original (FB)
Blade length: 710mm
Root thickness: 12mm
Overall blade weight: 185.9g
Chord in middle: 64mm
Thickness (mm/%) in middle: 8.7mm/ 13.5%
Distance of bolt hole from leading edge: 16mm
Distance of chordwise CG from leading edge: 18mm
Distance of spanwise CG from bolt hole: 375mm
Description: Symmetrical, constant chord, constant thickness blade, slightly swept tip.
Comments: Rearward chordwise CG less desirable for speed flying.


Blade name: Radix FBL (V1)
Blade length: 710mm
Root thickness: 12mm
Overall blade weight: 197.2g
Chord in middle: 64mm
Thickness (mm/%) in middle: 8.7mm/ 13.5%
Distance of bolt hole from leading edge: 16mm
Distance of chordwise CG from leading edge: 16mm
Distance of spanwise CG from bolt hole: 381mm
Description: Symmetrical, constant chord, constant thickness blade, slightly swept tip.
Comments: Good for speed flying, stable.


Blade name: Radix V2 (FBL)
Blade length: 710mm
Root thickness: 12mm
Overall blade weight: 202.0g
Chord in middle: 64mm
Thickness (mm/%) in middle: 8.7mm/ 13.5%
Distance of bolt hole from leading edge: 16mm
Distance of chordwise CG from leading edge: 16mm
Distance of spanwise CG from bolt hole: 363mm
Description: Symmetrical, constant chord, constant thickness blade, slightly swept tip.
Comments: Good for speed flying, stable but slightly faster cyclic than Radix FBL (V1).

[TheKingPhisher]

Has anyone tried the new SAB Blackline 2D blades for speed flying? They're supposed to be more stable than 3D blades but also capable of doing 3D as well so you don't have to swap them out for specialized "speed only" blades.

I'm building a Goblin Speed "770" and will be using the Blackline 2D blades.

I'm not planning to do any type of competition level stuff so it doesn't have to be superfast as long as it can do some 3D without having to change setups.

[Dyain Frazier]

Can any one help me on what blades to buy for speed

[TheKingPhisher]

Originally Posted by Dyain Frazier

Can any one help me on what blades to buy for speed

Why not try the 720mm speed specific blades from SAB?

[dude25]

I was running on my TDR Radix 710 FBL V2, these are actually my favourite allrounder blades.

Since a couple of flights Im running Radix 710 FAI blades with the golden spikes, the blades are aroung 220gr weight each. These blades are fantastic for speed runs, very locked in, as flying on rails. the center of gravity is around 4cm more outward than the Radix 710 FBL V2 and 2cm compared to DH711 Blades which are also pretty good for speeding.

Saw last week a TDR with the XBlades 713 mounted, incredible wide blades, look fantastic

[jhamel]

It is almost 2018. I assume there is now plenty of accumulated experience with "speed" blades. The "speed" blades that pop up on my search include the following:

1) X-Blades 713

2) DH711

3) Radix 710 V2 FBL

4) Rail 716

5) SAB Thunder Carbon 720

What is the verdict on 700 size speed blades?

[wadders248]

X-Blades 713 are the best over 2,500rpm

Not on your list are the Radix 710 FAI, which are probably the best before you move to the X-Blades 713.

[jhamel]

Thank you for your reply. Would you be able to further educate me on advantages/disadvantages or current "speed" blades? What "speed" blades work best at certain head speeds? What "speed" blades are definitely optimized for FFF speed flying and are no good for 3D flight? Thank you in advance.

[plankdriver]

Let me give you my insight into hobby blades for speed, strictly speaking of 700 size heli. My background is 7 years conducting speed cup events in the US, and competing in the top class for the last 4 years achieving speeds reaching 175mph. (~163mph ave.)

These are the top blades observed in competition.


Rail 716 Speed (AKA 716 FAI) : Stable, clean up to 2400-2500 RPMs and up to ~145mph ; popular and commercially available

DH 711: Very similar to the Rails

SAB 720 Speed: Also a good blade for up to 145mph, and commercially available

Radix 710 FAI. Very efficient, low drag up 145-150mph, hard to find.

Rotortech 720 FAI or Scott Gray: My personal blade for sport speed model, fast and stable up to ~150mph; hard to find

Above 150mph and 2600RPM,
X-Blades 713s: best commercial blade for high speed helicopters, very stable and designed for 150MPH plus and high RPM. Beware, this blade does not work well at lower speeds, just not made for slow <150mph

Scorpion Speed Blades: Designed for very low drag at high RPMs. Even more stable than the XBlades. Must be spun at higher RPM in order work best at 160mph and higher. (Not commercially available)


Santiago
Model Helicopter Speed Flying Association

[Vinger]

Agree with Santiago those are my exact same findings.