Rotors

Sv.grainne

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I'm not confused and Razor Blades (Gyro Technic) were not an option when my manual was published, 2012 version and it states G1SA and G1SB. Will see what Brian finds out from Nicolas.
 
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Brian Jackson

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GyroBee Variant - Under Construction
The following is my communication with Nicolas @ Aviomania. Green text is me, blue text is Nicolas:

__________________________________________

Hello Nicolas.

My name is Brian Jackson and I am writing to you from the US. I was encouraged to contact you about your experience with Gyro-Tech carbon rotors on the Genesis. I am currently building a single-seat gyro from plans (GyroBee)and have purchased 24' Gyro-Tech blades and also a matching Gyro-Tech rotorhead. I am told by their factory it is a suitable rotor for this ship.

A gentleman from the Rotary Forum (www.rotaryforum.com) mentioned that you may have tested these blades on your single-seat Genesis, and if so, would you be kind enough to tell me how they worked out for you? I have not yet begun my training as the build is still under construction, but am hopeful to learn your thoughts on this rotor on a light, single place ship. (Estimated AUW = 500 lbs / 227 kg) I would be very grateful for any insight.

Thank you kindly.

Respectfully,
Brian Jackson

___________________________________________

Hello Brian. All the best with your built.

Yes I have tested the Gyrotech rotors on both my single and dual seat models. For the 2 seat are not so bad... not the best blades but they were OK.

Unfortunately for the single seat and specially for a light gyro like Gyrobee they are not good!!!. They are TOO HEAVY and the gyroplane will be difficult to handle on the ground, be prone to ground loops and ground roll will be unstable.

Our Genesis is 300 Kg MTOW (660 lbs) and did not handle nicely.... it was flying ( we had about 15 hours on them) and tried to set the gyroplane so it can handle better... but they never performed as nice (both in performance but most importantly in handling) as the dragon wings... or even the Macuchens we tried.

They also tend to float and balloon with a light gyroplane as they maintain their inertia longer due to the weight making landing a bit more of a ritual!!!

The gyrobee was not designed to handle that much weight on top of the mast ..... so.. this with the combination with a novice pilot will make it much more difficult and dangerous than if you have chosen lighter blades.

Sorry for disappointing you with my email.... but I prefer to help you to enjoy your venture into gyroplanes, as I enjoy mine than to sound supportive and cause you to straggle and maybe hurt yourself.

For me the order of safe gyro flying is:
Good balanced Gyroplane design, Good training, good pre-flight checks and maintenance, airmanship, currency.

You now are in the first two MOST important phases in your gyroplane journey!!! So please built a nicely balanced gyroplane and take good flight training!!!

My best and most sincere wishes for success in your gyroplane journey!!

Best regards,
Nicolas Karaolides

The Aviomania Team.


_____________________________________

Thank you, Nicolas.

Not the news I'd hoped for but I prefer the grim reality over the foolish dream. I sincerely appreciate you taking the time to educate me on both your testing and your opinion of these blades on a light ship. These were my concerns as well, and having you explain them to me made them valid. I will share this information with others on the Rotary Forum who may be considering using these blades on a light gyro.

It's always disheartening to realize one's mistake after such a large investment, but where safety is concerned the money is irrelevant. Perhaps I can find a buyer who is interested in this rotor and head. If you happen to know of anyone please let me know, everything is brand new and mint condition. An even trade for a more suitable, lighter rotor might be worth pursuing.

Thank you again for the great review, even though it wasn't the kind of 'great' I'd hoped. I hope we can communicate in the future, and I appreciate the encouragement as a soon-to-be pilot in training. Have a wonderful day.

Respectfully,
Brian Jackson

______________________________________________
End of comm
______________________________________________

So, not the news I'd anticipated, but the news I needed. Hard lesson.
 

rcflier

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409
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Nexø (Denmark)
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Auto-Gyro MTO Sport 914
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Brian, are you sure Nicolas tested the same blades as those you have? Yours are special.

Your rotor is an older type, made for something like a Gyrobee. And you know they stopped building them.

Maybe the single person gyro blades Nicolas tested are of the newer, wider and probably heavier variety?

Don't give up too soon - maybe you have been discussing apples to oranges.

I have a never-used 23' McCutchen Skywheels rotor from 1989 I bought for a single build.

But I'm sure it would be prohibitive to send it back to the US...
 
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Brian Jackson

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Brian, are you sure Nicolas tested the same blades as those you have? Yours are special.

Your rotor is an older type, made for something like a Gyrobee. And you know they stopped building them.

Maybe the single person gyro blades Nicolas tested are of the newer, wider and probably heavier variety?

Don't give up too soon - maybe you have been discussing apples to oranges.

I have a never-used 23' McCutchen Skywheels rotor from 1989 I bought for a single build.

But I'm sure it would be prohibitive to send them back to the US...
Ignoring flight characteristics for a minute, what Nicolas is describing is the mass, and the inherent difficulty in ground handling that will result when maneuvering such a mass on a long moment arm of such a light ship. This is the 'balance of design' he was referring to, and part of my original concern about over-stressing the airframe.

I will continue our communication to learn which model he tested, but considering his concern with 'floating' and 'balooning' during landing, I would assume the issue may be even more pronounced the lighter the gyro, with the GyroBee on the extreme end of that spectrum. Additionally, the blades I have are a special 'high lift' airfoil, so I would expect the floating issue to be further amplified by the lack of AUW.

These sound like great blades for a heavy-ish ship. But another concern mentioned by (I think) GyroJake in a past thread was loading, and the possibility of dangerously low RRPM if the gyro was too light.

I'm just looking at all these factors collectively and not getting a warm happy feeling. Even if somehow all of these details could be addressed individually, that would put me in the unfortunate position of being a test pilot instead of the student I need to be, which my gut says is a recipe for disaster. So I think the decision has already been made to err on the side of caution and listen to the experts. I would much rather lick a financial wound than bandage a physical one.
 

rcflier

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Hi Brian.

Another member of our community bought a Rotor-Tech rotor from Poland.

And it seemed like it was designed by the same person who went from Gyro-Tech to Rotor-Tech.

He put it on his Cavalon and mentioned short take-off and better mileage - but much lower rotor speeds.

His blades are 198 mm wide and the rotor is the standard size of 8.4 meter.

My blades are 216 mm wide and of same length. But my MTO Sport is much lighter, so I was very worried

that too low rotor RPM would make them unusable.

But the RPM's are right in the ballpark. Recommended RPM 320 - 390 with 420 max.

One slim pilot up with a small amount of fuel was 320. 2 up with a small amount of fuel

gave 340 - 350, depending on the density altitude. So that's perfect.

It's 8 kg heavier than the Auto-Gyro rotor, though.

But it vibrates way too much, so there is still work to do.

I am annoyed that I didn't ask about leading edge protection - I thought it was standard.

Cheers
Erik
 
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Kevin_Richey

Yamaha gyro...Oregon, USA
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Brian: I'm going to disagree w/ Nicolas. I believe your Gyro Tech rotorblades will serve you fine for a light single-place gyro such as your GyroBee, based on my experience flying several different types of gyroplanes.

My personal opinion is that N.K. is highly experienced in gyro flying, combined w/ his engineering credentials, & armed w/ that combination of smarts & experience found how the Gyro Tech rotors perform for his brand of gyroplanes.

Please don't feel you've made a huge mistake in your purchase. All gyro rotorblades do the job decently. Some exhibit a few traits that you'll notice some differences, such as how long it takes to prerotate them, how the machine climbs & the landing phase.

Some rotorblades, such as the ones made by Igor Bensen, Rotordynes, & the Ken Brock ones, are super easy to hand-start. The Bensen & Brock blades are known as not having great climb performance. Adequate, but some others do better in that category. Chuck Beaty has explained the reason for this many times.

Skywheels are heavier & take awhile to hand-start. It is virtually impossible to do the same w/ the Ernie Boyette Dragon Wings, due to their airfoil design that makes them great performers, but so difficult to get them "over the hump" (blade stall) into enough rpms to start taxiing to feed more air into the rotor disk to have them start speeding up to flight rpms.

I do not have an aeronautical or engineering degree. I've 75 hrs. flying McCutcheon Skywheels (heavy fiberglass construction). Those hrs. were flown using a Vancraft Rotor Lightning. That was my first experience, prior to having dual instruction. Additionally, I have some 250+ hrs. flying Sport Copter's Sport Rotors.

I have one El Mirage flight in my own Sport Copter gyro trying a set of 25' Dragon Wings after hundreds of hrs. under 25' Sport Rotors. W/out any scientific proof, such as accurate measuring, I felt the Dragon Wings might have a shade better climb performance than my Sport Rotors, but that was only a shade in seat of the pants measurement! That same seat of the pants measuring indicated that the DW took a bit longer of a takeoff roll to nurse them up to enough rrpms to hit full power on the takeoff roll. I had no functioning rotor tach to tell more accurately @ which rrpms the difference was.

I & a few others were coached over a CB radio by a fellow PRA chapter member (who had oodles of helicopter time from his Army service, as well as him owning/flying his own Vancraft R.L.), through the extensive balancing on the mains & then progressing to crow hops, & then S-turns flying down the runway using 23' Skywheels.

The Jim McCutcheon Skywheels rotorblades performed well. Very smooth in all phases of flight. They do have a high amount of float when you want to land. Flaring causes the gyro rotors to speed up, creating this float by loading extra energy into the rrpms. Chuck Beaty has explained the reason for this numerous times on this forum. Balanced too far past the 25% chord line is the culprit.

Most of my experience landing is @ engine-idle, which makes one ready for a power-off landing when it might occur. This technique is taught by CFIs Ron Menzie & Jim Vanek. Gyroplane power-on landings require a slightly different technique.

Guys who have flown Skywheels & experiencing the sudden mid-air flare have almost exclusively been in heavier 2-place gyros, such as Steve McGowan's "Black".
Glenn K. in Utah also had the same happen to him in his Butterfly gyro, which is heavier than the light gyros, & didn't have one of those mid-air flairs when he still had a 2-stroke engine as his powerplant. He had switched to the heavier Yamaha 4-stroke engine & was somewhere north of 80 mph when the flair happened.

Don't feel you have made an expensive mistake & have to sell off your Gyro Tech rotorblades, and switch to Dragon Wings or Gyro Technic ones, because you fear that you'll crash while flying them because they exhibit dangerous characteristics. That is something you might wish to do later, after you've mastered solo flight & have time up flying your GyroBee.

The fools who take off prematurely b-4 the rotorblades are up to flight speed by horsing their gyro off the ground (like one rotates an airplane @ a certain A/S), & are too nose high flying way behind the power curve, deserve the results their impatience brings. All of that is covered by a CFI's instructions & demonstrations. A gyroplane tells the pilot when it is ready to fly, not the other way around. We're not flying Beluga whales here!

Again, my opinion, your Gyro Tech rotorblades will do just fine for your GyroBee. Trying different rotors after you've become proficient in all phases of gyroplane flight will come naturally.
 
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Brian Jackson

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Brian: I'm going to disagree w/ Nicolas. I believe your Gyro Tech rotorblades will serve you fine for a light single-place gyro such as your GyroBee, based on my experience flying several different types of gyroplanes.

My personal opinion is that N.K. is highly experienced in gyro flying, combined w/ his engineering credentials, & armed w/ that combination of smarts & experience found how the Gyro Tech rotors perform for his brand of gyroplanes.

Please don't feel you've made a huge mistake in your purchase. All gyro rotorblades do the job decently. Some exhibit a few traits that you'll notice some differences, such as how long it takes to prerotate them, how the machine climbs & the landing phase.

Some rotorblades, such as the ones made by Igor Bensen, Rotordynes, & the Ken Brock ones, are super easy to hand-start. The Bensen & Brock blades are known as not having great climb performance. Adequate, but some others do better in that category. Chuck Beaty has explained the reason for this many times.

Skywheels are heavier & take awhile to hand-start. It is virtually impossible to do the same w/ the Ernie Boyette Dragon Wings, due to their airfoil design that makes them great performers, but so difficult to get them "over the hump" (blade stall) into enough rpms to start taxiing to feed more air into the rotor disk to have them start speeding up to flight rpms.

I do not have an aeronautical or engineering degree. I've 75 hrs. flying McCutcheon Skywheels (heavy fiberglass construction). Those hrs. were flown using a Vancraft Rotor Lightning. That was my first experience, prior to having dual instruction. Additionally, I have some 250+ hrs. flying Sport Copter's Sport Rotors.

I have one El Mirage flight in my own Sport Copter gyro trying a set of 25' Dragon Wings after hundreds of hrs. under 25' Sport Rotors. W/out any scientific proof, such as accurate measuring, I felt the Dragon Wings might have a shade better climb performance than my Sport Rotors, but that was only a shade in seat of the pants measurement! That same seat of the pants measuring indicated that the DW took a bit longer of a takeoff roll to nurse them up to enough rrpms to hit full power on the takeoff roll. I had no functioning rotor tach to tell more accurately @ which rrpms the difference was.

I & a few others were coached over a CB radio by a fellow PRA chapter member (who had oodles of helicopter time from his Army service, as well as him owning/flying his own Vancraft R.L.), through the extensive balancing on the mains & then progressing to crow hops, & then S-turns flying down the runway using 23' Skywheels.

The Jim McCutcheon Skywheels rotorblades performed well. Very smooth in all phases of flight. They do have a high amount of float when you want to land. Flaring causes the gyro rotors to speed up, creating this float by loading extra energy into the rrpms. Chuck Beaty has explained the reason for this numerous times on this forum. Balanced too far past the 25% chord line is the culprit.

Guys who have flown Skywheels & experiencing the sudden mid-air flare have almost exclusively been in heavier 2-place gyros, such as Steve McGowan's "Black".
Glenn K. in Utah also had the same happen to him in his Butterfly gyro, which is heavier than the light gyros, & didn't have one of those mid-air flairs when he still had a 2-stroke engine as his powerplant. He had switched to the heavier Yamaha 4-stroke engine & was somewhere north of 80 mph when the flair happened.

Don't feel you have made an expensive mistake & have to sell off your Gyro Tech rotorblades, and switch to Dragon Wings or Gyro Technic ones, because you fear that you'll crash while flying them because they exhibit dangerous characteristics. That is something you might wish to do later, after you've mastered solo flight & have time up flying your GyroBee.

The fools who take off prematurely b-4 the rotorblades are up to flight speed by horsing their gyro off the ground (like one rotates an airplane @ a certain A/S), & are too nose high flying way behind the power curve, deserve the results their impatience brings. All of that is covered by a CFI's instructions & demonstrations. A gyroplane tells the pilot when it is ready to fly, not the other way around. We're not flying Beluga whales here!

Again, my opinion, your Gyro Tech rotorblades will do just fine for your GyroBee. Trying different rotors after you've become proficient in all phases of gyroplane flight will come naturally.
Thank you, Kevin.
Good points and fortunately no keep/sell decision need be made today. There's enough to keep me busy on the build until then. This is a perfect exercise in removing emotion and sunk cost from the decision making equation, similar to the Concorde Fallacy: https://en.wikipedia.org/wiki/Sunk_cost

I appreciate your robust assessment and greatly value your experienced opinion. What this shows me is that there's more study to do before its time to mount A rotor, be it the one I have or a more suitable replacement. In the mean time, I did receive another reply from Nicolas, as follows:

You are welcome Brian.

I love gyroplanes and for me promoting safety in our sport is of outmost importance (even though I manufacture gyroplanes I only supply what I feel is best, safest and less compromised…. And not what customers want… but business… but clear conscience and happy when my customers realize how fun and easy flying a gyroplane can be)

Reference my review it does not mean that Gyrotech cannot be flown on a light gyroplane….. but as I said they pose dangers and difficulty!! Gyrotech are still an option for our single seat… but I strongly advice against using Gyrotech…… especially to new pilots.

Best regards,

The Aviomania Team.

www.aviomania.com
 

Brian Jackson

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Brian, are you sure Nicolas tested the same blades as those you have? Yours are special.

Your rotor is an older type, made for something like a Gyrobee. And you know they stopped building them.

Maybe the single person gyro blades Nicolas tested are of the newer, wider and probably heavier variety?

Don't give up too soon - maybe you have been discussing apples to oranges.

I have a never-used 23' McCutchen Skywheels rotor from 1989 I bought for a single build.

But I'm sure it would be prohibitive to send them back to the US...
I'm sure they were different blades, but I did reply back asking which rotor he tested. Hopefully his kindness continues while I'm pestering him for data. I can't expect someone to drop everything to answer questions for a non-customer. But here is my reply to Nicolas. Will post response when he is able.
_______________________________
Thank you again, Nicolas.

It has been a real pleasure getting to chat with you. If you don't mind, and so I may better understand the problem, could you please tell me the size of the Gyro-Tech rotor you tested? The reason I ask is because the 7.3 Meter [24 ft.] Gyro-Tech rotor I currently own is only 203 mm [8"] chord (now discontinued) instead of their standard 216 mm [8.5"] chord. The airfoil is also slightly modified from their current 8H12 and was marketed as a "high lift" blade.

Sorry to be a pain asking all the questions, and I sure do appreciate your taking the time to be so helpful. I'm just trying to collect data for myself and others in order to better assess the issues you encountered in your testing. I am grateful to you for sharing your experience with me. Thank you again.

____________________________________
The concern I have with disc loading (if I'm using that term correctly) is that my rotor is 24', which when that area is divided by 500 lbs. AUW gives a value of 1.1 lbs per sq. ft. I am told this is low and could be problematic. However the original Taggart GyroBee used a 24' rotor and was a good bit lighter than mine with its 447 engine. He makes reference to the disc loading in the documentation so I am going to re-read that section tonight.

By the way, I'm sorry if I've hijacked this thread from the OP. Just seemed a good place to have this discussion. So glad our Rotary Forum is still here.
 

Kevin_Richey

Yamaha gyro...Oregon, USA
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Brian: I have to add that I have no experience w/ Gyro Tech rotorblades, let alone seeing any in person. I also have no expertise in materials used in the manufacturing of them, whether they be wood, aluminum, extruded or not.
I have heard from Jim Vanek several times that extruded rotorblades are not 6061-T6, as it does not extrude well. 6063 is architectual-grade aluminum, which is supposed to be far weaker in strength. JV emphasizes strength & over-built in his products, since people's lives depend on what is used in the construction process for aviation.
 

DASBUR

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Burlington Wi
I'm not confused and Razor Blades (Gyro Technic) were not an option when my manual was published, 2012 version and it states G1SA and G1SB. Will see what Brian finds out from Nicolas.
I received a test set of blades from Gyro Tech Poland. They were suppose to be a direct replacement for the helicycle aluminum blades. Due to the way they are constructed the blade span balance was off about 10 inches from what the stock Helicycle blades were. The blade is normally tail heavy so they overbalance it at the tip to compansate. They gave me a report of the changes that would need to be made to the rotorhead to make the blades work. I informed them they suppose to be direct replacements. they are now going to build up another design the suppose to better match the aluminum blades. I think it may be the same on a Gyro any different weight distribution on the blades would require changes in teeter height and cone angle.

Doug
 

Brian Jackson

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For those interested, I was able to quickly locate the pertinent info from Ralph's GyroBee documentation. I've highlighted (in bold) the bits related to the recent discussion:
___________________________________

Rotor Blades
Rotor blades are critical with respect to several aspects of the Gyrobee, including performance and legality. The Gyrobee has been flown on all the blades listed below and I have included some notes with respect to each option:

Dragon Wings
Current production Dragon Wings (those with a reflexed trailing edge) are very light and fly the gyro very well. Unfortunately, they cannot reliably hand-started so a prerotator would be required. Fortunately they are light enough that you could add a basic Wunderlich prerotator and keep your machine Part 103-legal with respect to weight. The top speed of your machine may exceed 55 knots (63 mph), but weight is a bigger issue with respect to Part 103 than speed (within reason!). A 23-foot rotor disc is adequate with these blades.

Sport Copter Blades
These are very smooth blades and, while not quite as efficient as the Dragon Wings, they do a fine job. They will hand start but are light enough that a prerotator may be legal. Good performance would mandate the use of a 24-foot rotor disc.

Rotordyne Blades
These are solid blades that hand-start easily. Unfortunately,they are too-heavy to permit the use of a standard prerotator. A 25-foot rotor disc would be optimum with these blades.

Rotor Hawk Blades
These blades are more difficult to set up initially, but will provide adequate performance on a 24-foot rotor disc and hand-start easily.

Brock Blades
These blades are light and hand-start very easily. There is enough of a weight margin for the use of a prerotator. Performance is adequate with a 24-foot disc but the blades do not conserve energy well. As a result, you get essentially one chance to execute your round-out before the blades play out.

Sky Wheels
These blades will perform well in the 24-25-foot range but the blades are so heavy you may not make Part 103 weight.

Rotor Disc Diameter
The major problem early in the flight-testing of the prototype was how to get a good climb rate when using blades of moderate performance and an engine of only 40 hp. Fixed-wing ultralights solve the problem by having a relatively high wing area for their weight, resulting in low wing loading. The solution with the Gyrobee was similar -increase the diameter of the rotor disc to improve the disc loading. The typical single-seat gyro flies at a disc loading of 1.2 to 1.4 pounds/square foot (psf) with engines in the 65-90 hp range. In the case of the original Rotordyne blades, we used with a 5 foot hub bar, producing a
25 foot rotor disc and a disc loading of about 1.0 psf. This produced excellent performance yet the aircraft could easily be flown in winds up to 30 mph,assuming a reasonable level of pilot experience. The ten-foot Brock blades were lighter and were flown with a 4 foot hub bar, producing essentially identical disc loading on a 24 foot rotor disc. The tall mast provides ample rotor clearance in either case. Although the aircraft will fly at a disc loading of 1.2 psf, I do not consider the climb performance margin acceptable. Rotor disc diameter for the various blades options listed above has already been provided.
 

DASBUR

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Burlington Wi
For those interested, I was able to quickly locate the pertinent info from Ralph's GyroBee documentation. I've highlighted (in bold) the bits related to the recent discussion:
___________________________________

Rotor Blades
Rotor blades are critical with respect to several aspects of the Gyrobee, including performance and legality. The Gyrobee has been flown on all the blades listed below and I have included some notes with respect to each option:

Dragon Wings
Current production Dragon Wings (those with a reflexed trailing edge) are very light and fly the gyro very well. Unfortunately, they cannot reliably hand-started so a prerotator would be required. Fortunately they are light enough that you could add a basic Wunderlich prerotator and keep your machine Part 103-legal with respect to weight. The top speed of your machine may exceed 55 knots (63 mph), but weight is a bigger issue with respect to Part 103 than speed (within reason!). A 23-foot rotor disc is adequate with these blades.

Sport Copter Blades
These are very smooth blades and, while not quite as efficient as the Dragon Wings, they do a fine job. They will hand start but are light enough that a prerotator may be legal. Good performance would mandate the use of a 24-foot rotor disc.

Rotordyne Blades
These are solid blades that hand-start easily. Unfortunately,they are too-heavy to permit the use of a standard prerotator. A 25-foot rotor disc would be optimum with these blades.

Rotor Hawk Blades
These blades are more difficult to set up initially, but will provide adequate performance on a 24-foot rotor disc and hand-start easily.

Brock Blades
These blades are light and hand-start very easily. There is enough of a weight margin for the use of a prerotator. Performance is adequate with a 24-foot disc but the blades do not conserve energy well. As a result, you get essentially one chance to execute your round-out before the blades play out.

Sky Wheels
These blades will perform well in the 24-25-foot range but the blades are so heavy you may not make Part 103 weight.

Rotor Disc Diameter
The major problem early in the flight-testing of the prototype was how to get a good climb rate when using blades of moderate performance and an engine of only 40 hp. Fixed-wing ultralights solve the problem by having a relatively high wing area for their weight, resulting in low wing loading. The solution with the Gyrobee was similar -increase the diameter of the rotor disc to improve the disc loading. The typical single-seat gyro flies at a disc loading of 1.2 to 1.4 pounds/square foot (psf) with engines in the 65-90 hp range. In the case of the original Rotordyne blades, we used with a 5 foot hub bar, producing a
25 foot rotor disc and a disc loading of about 1.0 psf. This produced excellent performance yet the aircraft could easily be flown in winds up to 30 mph,assuming a reasonable level of pilot experience. The ten-foot Brock blades were lighter and were flown with a 4 foot hub bar, producing essentially identical disc loading on a 24 foot rotor disc. The tall mast provides ample rotor clearance in either case. Although the aircraft will fly at a disc loading of 1.2 psf, I do not consider the climb performance margin acceptable. Rotor disc diameter for the various blades options listed above has already been provided.
All aluminum with the exception of the sky wheels. the old school way of making blades is that they need to balance at 25% through the entire length of the blade. new school composite seems does not matter what the chord balance is we can just overbalance it at the tip to get 25% that works as long as the rotor head is designed for it.

Doug
 

wolfy

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I think they will be fine Brian, to me a disk loading of 1.1 is near perfect and lets a gyro fly like a gyro should.
There won't be a huge amount of extra float on landing because the light disk loading means a slower rotor rpm (it will still be well within spec) which also means less energy retention.
With the extra weight up top you should always taxi with rotors turning a decent rpm, I won't taxi anywhere without rotors turning and the rougher the ground the higher the rpm.

wolfy
 

Resasi

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By the way, I'm sorry if I've hijacked this thread from the OP. Just seemed a good place to have this discussion. So glad our Rotary Forum is still here.
This discussion is precisely the sort of debate, and information exchange that is entirely appropriate in this thread Brian.

It is valuable information that is being shared for the benefit of all of us, and I heartily endorse the gratitude we all feel to Todd for the continuation of the Forum.
 

Brian Jackson

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This discussion is precisely the sort of debate, and information exchange that is entirely appropriate in this thread Brian.

It is valuable information that is being shared for the benefit of all of us, and I heartily endorse the gratitude we all feel to Todd for the continuation of the Forum.
Wholly agreed.

As for lucid decision making, sleeping on it has helped. Perhaps the best course of action is to take none at all. I will continue as planned, using the existing Gyro Tech rotor and head. Since the ship will be test flown by someone with experience and way more knowledge than me, their evaluation will dictate if there is a need to replace the rotor system. If so, it's a reasonably simple process. If not, then we'll have a sweet gyro that's finally finished.

Thank you to all whom have chimed in on this thread. Once again I have learned much from you.
 

Brian Jackson

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Aircraft
GyroBee Variant - Under Construction
I think they will be fine Brian, to me a disk loading of 1.1 is near perfect and lets a gyro fly like a gyro should.
There won't be a huge amount of extra float on landing because the light disk loading means a slower rotor rpm (it will still be well within spec) which also means less energy retention.
With the extra weight up top you should always taxi with rotors turning a decent rpm, I won't taxi anywhere without rotors turning and the rougher the ground the higher the rpm.

wolfy
Hi Wolfy.

Is that because you want the centrifugal force of the blades to resist excessive blade flex on uneven ground? Or is there another reason I'm unaware of?
 

Brian Jackson

Platinum Member
Joined
Jul 17, 2004
Messages
3,259
Location
Hamburg, New Jersey USA
Aircraft
GyroBee Variant - Under Construction
Quick update. Nicolas of Aviomania wrote back to me that he would reply on this thread in a few days when he returns regarding the particulars of the Gyro Tech rotor he tested. One thing I neglected to ask was if the Gyro Tech rotorhead was also used during testing or if the rotor was simply swapped on an Aviomania head. I don't know if that makes a difference in flight characteristics but seem to remember a past discussion here about our late member Eddie having some difficulty adapting his to a Sport Copter head on his RAF.

Anyway, Nicolas seems like a really great guy and am happy he will be adding his wealth of experience to this discussion. Looking forward to it.
 

rcflier

Junior Member
Joined
May 24, 2007
Messages
409
Location
Nexø (Denmark)
Aircraft
Auto-Gyro MTO Sport 914
Total Flight Time
30+
While we are discussing rotors...
My instructor testflew my gyro again today.

He stated, that it's not easy to fly fast, although he went to 180 km/t.
But he couldn't trim it to fly hands off for more than ca. 130 km/t.
I can think of two reasons: The rotor may be too "large" for the MTO (blades too wide),
and/or I used the old Type1 head, where the teeter towers are higher
than Gyro-Tech's own. I made new, higher stop blocks myself.

And when he put on power, it wanted to lift the nose. I imagine,
it then has a large amount of drag - although it's very effective,
cruising with 300 rotor RPM at 120 km/h speed with ca. 4000 RPM.
 
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