Gyro Tech vs Sportcopter Blades

SIIaCanuck

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Dec 3, 2012
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Alix, Alberta
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RAF 2000 2.5 GTX
Total Flight Time
3500hrs +
All,

I'm just looking for pros vs cons of Gyro Tech or Sportcopter blades for an RAF 2000. Not a question about rotor heads, that's a different issue (albeit related).

Thoughts on efficiency, lifespan and rotating moment of inertia, hub design, etc.

Stew
 

Alan_Cheatham

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Nov 14, 2003
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Dallas, Texas
 

SportCopter

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Scappoose
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Vortex M912, SportCopterII, Vortex 582
All,

I'm just looking for pros vs cons of Gyro Tech or Sportcopter blades for an RAF 2000. Not a question about rotor heads, that's a different issue (albeit related).

Thoughts on efficiency, lifespan and rotating moment of inertia, hub design, etc.

Stew
Hello Stew,

Thank you for inquiring aloud about Sport Rotors, which have been installed (often with our upper mast plates, rotorhead, and 4-way air-trim) on many RAF 2000s.


We use only aerospace-grade materials (6061-T6), and we do not extrude the skins (or entire profile) but instead bond the skins with Boeing's process to the leading edge spar.

Our 8.5" chord blades come with our well-proven 6061-T6 hub bar (with Heim-jointed NAS bolts allowing the blades to smoothly position for lead-lag and coning angles).

Compared to the new Gyro-Tech blades (which seem to have a good reputation so far), Sport Rotors should provide a slightly faster cruise AS at identical power setting.

Our longevity may be the highest in the gyro industry: 2000 hours, thereafter on condition. I.e., there is no ___ hours "time out."
We know of blade sets still safely flying with 3000+ hours.

We have never had a single in-flight blade or hub bar failure.
Even during full RRPM impacts, our Sport Rotor system remains intact.
Some of our customers have flown through power lines or chopped their own prop, yet landed safely.

Below are some links from one of our 2015 customers, an RAF 2000 owner:


Stew, your being a "3500+hr military rotary puke" you'll really appreciate our engineering, quality, and performance since 1958.
Feel free to give Jim Vanek a call here at 503-543-7000 to discuss our Sport Rotors further!
 
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SIIaCanuck

Member
Joined
Dec 3, 2012
Messages
110
Location
Alix, Alberta
Aircraft
RAF 2000 2.5 GTX
Total Flight Time
3500hrs +
Thanks for the responses, it's certainly given me plenty of food for thought.

Stew
 

SIIaCanuck

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Joined
Dec 3, 2012
Messages
110
Location
Alix, Alberta
Aircraft
RAF 2000 2.5 GTX
Total Flight Time
3500hrs +
Sport Rotors are the best! But those are the only ones I have owned.
Obviously that's a common view for many makes of blades. I happen to really like Aerospatiale/Eurocopter blades for the same reason, they've kept me airborne for several thousand hours. I've heard predominantly positive things about Sport Rotors, so that's a good sign, particularly from a longevity and safety perspective.

However, I'm not going to reject the potential that perhaps someone else makes better ones, or at least competitive ones with perhaps more desirable characteristics for my type of flying.



The impression I get is that Sport Rotors offer significant cruise performance advantages over RAF rotors. However, and I would like Sportcopter to comment on this, my reading of many reports of their flying characteristics is that they have more negative pitching moment than other rotors. This leads to a rotor system that is relatively trim neutral WRT forward speed, if taken too far.

The benefit of having flapback (I'm assuming Americans call it 'blowback' from reading several threads) is that one of the limits of forward speed becomes 'the limit of forward cyclic movement'. Rotor blades exhibiting excessive negative pitching moment have the opposite problem, you run out of aft cyclic and then your relatives get to have a wake in your memory. A well designed helicopter rotor system would run out of forward cyclic somewhere near VNe, meaning any further increase in power simply produces a climb. Of course there are reasons to have some excess forward cyclic at VNe, but not much.

So, the question I have is, how speed stable in trim are Sport Rotors? If one is doing aerial camera work, could one trim at 60 in a Sport Rotor equipped RAF (keel drop NCLT), expecting increased power to introduce climb (at 60 +/- 10%) and reduced power producing descent (at 60 +/- 10%)?



I'm also interested in the same answer regarding Gyro-Tech's rotors. From what I gather they perform well at low speeds, particularly retaining good energy out of the flare. For my requirements, this high rotating moment of inertia would be an advantage as absolute agility is not the priority.

Comments welcome.
 

SportCopter

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Scappoose
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Vortex M912, SportCopterII, Vortex 582
Hello Stew, thank you for your questions.

We're well aware of our airfoil's slightly negative pitching moment (-Cmo), as such was intentional. The goal of our airfoil design in total was to provide superior performance (shortest takeoff distances, higher cruise speed, and RRPM recovery). A moment is just that: some amount of force to be resisted. A negative pitching moment can be resisted, and we do so. Our blade design, materials, aerospace bonding, and quality control create our renowned torsional rigidity, which amply resists -Cmo runaway twisting or tuck. (Just to head off any specious comparison of Sport Rotors to the "twisting Venetian blinds" Göttingen 606 airfoil attributed to the 1935 crash of a Cierva C-30.)

Also, the pilot does not run out of aft stick even at Vne. (In fact, the stick doesn't move much at all with increasing airspeed. RAF owners here with Sport Rotors have attested to that, one of whom posted extensively about it here.) Jim Vanek has tested Sport Rotors in a power dive to 145 mph.

So, the question I have is, how speed stable in trim are Sport Rotors? If one is doing aerial camera work, could one trim at 60 in a Sport Rotor equipped RAF (keel drop NCLT), expecting increased power to introduce climb (at 60 +/- 10%) and reduced power producing descent (at 60 +/- 10%)?
Sport Rotors are very speed stable. Your dropped keel RAF with our blades could be easily trimmed at 60 for the power:climb coupling you mention.
In fact, 60 would be close to neutral trim AS (probably around 50).
Your RAF will likely fly similarly to NCLT Sparrowhawks (which usually have Sport Rotors).

In short, if Sport Rotors produced the undesirable effects of high AS twisting and reduced aft stick, we'd have all heard about it these past 20 years. On the contrary, Sport Rotors have never once failed their owners, and we work very hard to keep it that way. Please give Jim Vanek a call here at 503-543-7000 to chat about our blades for your RAF.
 
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