Gyro Technic, Inc. Rotor Blades

Mike G

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Denis
It’s nice to see a new rotor manufacturer arrive on the scene. I always admire guys who have the courage to start an enterprise.
I like your tip balance-weight socket and the fact that you haven’t blindly followed the classic “half moon” tracking feature that is fundamentally in error as explained here:
https://www.rotaryforum.com/threads/lessons-learned-by-a-superior-rotor-balancer.48218/#post-48218
The first person I know of who brought this error to light and explained that the half moon should be the other way up (as you have done) was Jean Claude Debreyer, if you got the idea from him it would be nice to give him a credit, if you worked it out for yourself, bravo.

Looking at your design you have a 2.375” radius, assuming a 20 TPI thread on your adjusting screw that means that a 5° rotation of your screw would give about 1’ of tracking change (one blade increases by a minute and the other decreases by a minute). Using a modern dynamic balancer you can see the tracking effect of a 1’ change so ideally your adjustment system needs to be able to consistently and repeatedly change blade pitch by increments of 1’. I assume you’re using socket head screws (grub screws) to tilt the hub bar, I have a similar setup on my rotor for chordwise shift and it’s very difficult to achieve the accuracy required due to things like the play between your Allen key and the socket head and the tolerances in the threads themselves.

If my thread did have some influence on your design it’s a pity you didn’t talk to me before cutting metal because I have since developed for another manufacturer an easier, more accurate and cheaper method of adjusting tracking without causing a chordwise shift.

Also you don’t appear to have added any sort of scales to allow the operator to see how much he has changed pitch or chord shift, from experience, when dynamically balancing, this is a valuable feature that is missed by all the manufacturers of the rotors I have seen. In fact I don’t see how you are adjusting the chordwise balance, maybe I missed something.

Personally I don’t like the idea of those two threaded holes in the centre of the hub bar. Threads are stress raisers and you have them at probably the most sensitive part of the hub bar. I assume you’ve carried out an FEA study to satisfy yourself that you have a healthy safety factor in there.

Well done for trying, I wish you success.

Mike G
 

Gyro Technic

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Kasota, MN
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Gyro Technic GTVX1
Denis
It’s nice to see a new rotor manufacturer arrive on the scene. I always admire guys who have the courage to start an enterprise.
I like your tip balance-weight socket and the fact that you haven’t blindly followed the classic “half moon” tracking feature that is fundamentally in error as explained here:
https://www.rotaryforum.com/threads/lessons-learned-by-a-superior-rotor-balancer.48218/#post-48218
The first person I know of who brought this error to light and explained that the half moon should be the other way up (as you have done) was Jean Claude Debreyer, if you got the idea from him it would be nice to give him a credit, if you worked it out for yourself, bravo.

Looking at your design you have a 2.375” radius, assuming a 20 TPI thread on your adjusting screw that means that a 5° rotation of your screw would give about 1’ of tracking change (one blade increases by a minute and the other decreases by a minute). Using a modern dynamic balancer you can see the tracking effect of a 1’ change so ideally your adjustment system needs to be able to consistently and repeatedly change blade pitch by increments of 1’. I assume you’re using socket head screws (grub screws) to tilt the hub bar, I have a similar setup on my rotor for chordwise shift and it’s very difficult to achieve the accuracy required due to things like the play between your Allen key and the socket head and the tolerances in the threads themselves.

If my thread did have some influence on your design it’s a pity you didn’t talk to me before cutting metal because I have since developed for another manufacturer an easier, more accurate and cheaper method of adjusting tracking without causing a chordwise shift.

Also you don’t appear to have added any sort of scales to allow the operator to see how much he has changed pitch or chord shift, from experience, when dynamically balancing, this is a valuable feature that is missed by all the manufacturers of the rotors I have seen. In fact I don’t see how you are adjusting the chordwise balance, maybe I missed something.

Personally I don’t like the idea of those two threaded holes in the centre of the hub bar. Threads are stress raisers and you have them at probably the most sensitive part of the hub bar. I assume you’ve carried out an FEA study to satisfy yourself that you have a healthy safety factor in there.

Well done for trying, I wish you success.

Mike G
Mike,
Thank you for the comments. Yes, I am quite excited about this business addition.

I can honestly say that I was not familiar with the thread you mentioned. A lot of good info there! I have saved this for later study.
More than a little hectic this week getting ready for Mentone! Yeah!
I do need to catch up on my reading... I have hardly been on the forum at all for the past 4 years or so.....

My design purpose of the radius was to maintain as much surface contact between the 2 pieces as possible. Having the center of rotation around the center of the teeter bolt just made sense to me.

Yes, I am comfortable with the cross section of the hub bar below the threaded holes. (as is the computer study)
Also, the full contact teeter block spanning the upper surface, along with being framed by the (4) bolts, further isolates the threaded hole features.

My most current design has changed the radius to 3.25"
You were close... 1/4"-28 (not 1/4"-20) Which now with the new radius equates to about 1' of rotation for an 11° turn of the screw.

I am all for precision! I must admit though, that an adjustment of only 1' is a little finer than I was expecting!

Most of my experience has been with Dragon Wings with their simple pop can shim under the teeter-block solution....
So with this, the finest adjustment possible with that system, would be a single .003" shim under one side of a 2.5" wide x 3" tall block.
This would equate to an angular adjustment of 4.16'.
The same angular adjustment via one of my 1/4-28's would require a 45° turn of the screw. (Easily obtainable with out too much "finesse")

I'm with you on the scale markings... The pictures you referred to were an earlier prototype... The ref markings were included on 2 units I made last week. (Picture)
No other chord-wise adjustments at this time... But we are continuously developing as needed!

Back to Mentone packing!
Denis
 

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Resasi

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Think you will find a very interested audience at Mentone Dennis, and hope the Minni State Fair went well for you. You have two very solid new offerings for the gyro world, and a good reputation as a perfectionist and master machinist. You started in the sport with a most impressive build log and have then spent the next few years refining that machine.

The GT-VX1 would in my opinion be a top contender for anyone who wanted a top quality, safe, stable, single seat gyro that would suite a beginner to learn on, up to someone that wanted a seriously agile turn and burn fun 'aerial dirt bike.'

As your reply to Mike has shown, you are open to advice, and, ready to incorporate improvements to your products. I got that immediately by your approach to your very first build. You have already attracted attention here in the UK with your Razor Blades as there will always be a place for quality rotors, and yours I am certain will be.

It is sad to see the unwarranted negative attention you have received on the Forum from one individual, but as you already pointed out his reputation has already been well established as one that comes across as unnecessarily adversarial, and unfortunately mean spirited. Any regular member of this Forum by now simply tunes him out, which is sad because he probably does have valid things to contribute.

Have fun at Mentone, and pretty sure you will be very well received there.
 
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Mike G

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Denis
Do I understand that you have not included a chordwise (shifting) adjustment in your design?

Your teeter block looks to be inspired by AutoGyro, what sort of teeter bearings are you proposing to use, bushes, roller/ball bearings or rod ends?
Mike G
 

Gyro Technic

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Gyro Technic GTVX1
Mike,
Correct. No chord-wise adjustments built into the bar at this time.
My current offerings are small 7" chord x 23'-25' systems to be used on relatively light, simple aircraft.
To control costs, I feel that it is not necessary to include features that the vast majority of the customers will never use.
(How many Benson blades or Dragon Wings do you honestly feel have been adjusted for Chord-wise balance?)
If so, some simple shims under the hat bushings would do the trick just fine.

The teeter bearings would of course be dependent on the rotor head that these will be fitted upon.
On my systems, I use Teflon-lined steel sleeve bushings (TU or DU depending on your manufacturer of choice) which have been working very well for me.

I did a quick google image search for an AutoGyro teeter block, but did not find much. I'll be at Mentone next week and take a close look at some of those designs.

You seem a little insistent that my designs are borrowed form others.. Again, I'm not sure what the AutoGyro block looks like, but the thought of two separate entities coming up with a design to connect a flat bar to a single pivot point via a wide base tapering up to a cylindrical feature concentric around the pivot point doesn't seem too hard to grasp.
I'll take a look next week. Maybe they are a spitting image of each other!
Back to packing.
Denis
 

Smack

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Wait, didn't AutoGyro study Magni who bought the technology from Tervamaki who was influenced by Bensen who studied WWII German autogyros and flew Pitcairn autogyros which were licensed by autogiro inventor Juan de la Cierva ???
Yep, Denis you blatant copy-cat, you...…..
;)
Brian
 

XXavier

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Wait, didn't AutoGyro study Magni who bought the technology from Tervamaki who was influenced by Bensen who studied WWII German autogyros and flew Pitcairn autogyros which were licensed by autogiro inventor Juan de la Cierva ???
Yep, Denis you blatant copy-cat, you...…..
;)
Brian

The AutoGyro rotorheads are very similar to those from ELA. The solution given by Magni is original and different. Chordwise adjustments are possible (if I remember correctly, that was a modification done after a suggestion from Mike Goodrich...) and tracking adjustments are just not possible. The people at Magni probably consider tracking adjustments as unnecessary...
 

fara

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Tracking is a fairly common adjustment that makes things smooth at a usable range of cruise speeds followed by span balance and then chordwise adjustment.

After having worked and taking balance classes with Mike G twice I think if we ever do our own hub bar I would definitely consult him to make sure things can be done as precisely as possible. The biggest complain I get from trike and airplane pilots about Gyroplanes generically is shaking whether hop or stick

Btw I just read this thread. Welcome to the rotor blade game Denis. I am sorry that a couple of people have again shown what they are really about. In their defense I don’t think that they are being malicious. I think they have no clue how biased they are and how ridiculous they look. I welcome US manufactured items when they are done with pride and finesse from any supplier. Wish you the best
 

Mike G

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Denis

As Brian implied, it would be very difficult, even impossible, to create a 2-bladed autogyro teeter rotor that didn’t have design features “borrowed from others”. I’d even say that it would be pretty stupid not to look at what others had done and “borrow” the best parts that had been proven over time.

You also reply that:

To control costs, I feel that it is not necessary to include features that the vast majority of the customers will never use.

Yet you include a more expensive and complicated system for tracking, I could ask how many customers will know how to track your rotors?.

It’s clear that you want to be the “original thinker” and that my posts annoy you so from now on I’ll leave you (and everyone else on this forum) alone. This thread reminds me of the reason I stopped posting on this forum a year or two ago when I wrote

“You can lead a donkey to water but you can’t make him drink”.

Nothing has changed.

Brian

A small correction, AutoGyro copied the ELA (some say they even got a copy of all the drawings) and contrary to what many say, ELA didn’t copy the Magni, they introduced a number of new features and ideas (not all good in my opinion but they were at least different) and many of these features have been carried over into other makes.

Xavier

AutoGyro rotor heads were identical to ELA (because they were copied), they have some different features now. The Magni solution is the one they purchased from Tervamaki (as Brian says). The original Tervamaki design didn’t have a chordwise or tracking adjustment and I believe the very early Magnis didn’t either. I had one of the early M16s and that had the chordwise adjustment screw that was designed and developed by Magni not me. Since September 2018 Magni rotors have a tracking adjustment feature and I was involved in the design of that.

Abid

Thanks for the confidence; as I said last year, it’s a waste of time posting here. You have my number if you need me.

Mike G
 

Gyro Technic

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Denis

As Brian implied, it would be very difficult, even impossible, to create a 2-bladed autogyro teeter rotor that didn’t have design features “borrowed from others”. I’d even say that it would be pretty stupid not to look at what others had done and “borrow” the best parts that had been proven over time.

You also reply that:

To control costs, I feel that it is not necessary to include features that the vast majority of the customers will never use.

Yet you include a more expensive and complicated system for tracking, I could ask how many customers will know how to track your rotors?.

It’s clear that you want to be the “original thinker” and that my posts annoy you so from now on I’ll leave you (and everyone else on this forum) alone. This thread reminds me of the reason I stopped posting on this forum a year or two ago when I wrote

“You can lead a donkey to water but you can’t make him drink”.

Nothing has changed.

Brian

A small correction, AutoGyro copied the ELA (some say they even got a copy of all the drawings) and contrary to what many say, ELA didn’t copy the Magni, they introduced a number of new features and ideas (not all good in my opinion but they were at least different) and many of these features have been carried over into other makes.

Xavier

AutoGyro rotor heads were identical to ELA (because they were copied), they have some different features now. The Magni solution is the one they purchased from Tervamaki (as Brian says). The original Tervamaki design didn’t have a chordwise or tracking adjustment and I believe the very early Magnis didn’t either. I had one of the early M16s and that had the chordwise adjustment screw that was designed and developed by Magni not me. Since September 2018 Magni rotors have a tracking adjustment feature and I was involved in the design of that.

Abid

Thanks for the confidence; as I said last year, it’s a waste of time posting here. You have my number if you need me.

Mike G
Mike,
Don't know if you will see this post, as you seem to have implied that you will no longer be visiting this forum.
If you do see this, and to everyone else, I'm sorry if you feel this escalated in tension. I was not at all annoyed with your posts. I thank you for your input!

It just seemed strange to me that an earlier post started out with
" if you got the idea from him it would be nice to give him a credit"
and then your next post starting with
"Your teeter block looks to be inspired by AutoGyro".

Of course we all borrow design ideas everywhere we look! Myself included! It just took me by surprise because I was honestly not aware of the 2 examples that were in discussion.

Again, I apologize if I came across as being upset.

To clarify my position on blade adjustments.

Static balance of the system: VERY important! (my design allows for the placement of tip weight additions)

Tracking: Very Important! I hope my design (which apparently I wasn't the first to conceptualize) makes for very easy precise adjustments.
Yes, I am confident that ALL of my customers will know how to track the rotors since it will be provided with the documentation.
Once I get some more testing completed, I will be able to include in the instructions a very simple table stating: If your "x" blade is tracking 1" high, then go to the setscrew marked with the X and give it a 45° turn clockwise. (Or whatever that value turns out to be...)

Chordwise adjustment: The finest adjustment you can make, and important if you want the absolute smoothest system possible. (Which I would, but I don't feel every one want to go to those lengths.)
I'm just willing to bet that the vast majority of people flying a Benson, Brock, Hornet, Gyrobee, Air Command, Dominator and what-else have never performed any chord-wise balancing actions. I'm sure some, but not many.

If this turns out to be a higher demand than I am currently picturing, then by all means, I will add that addition to the design.
But again, in its simplest form, a couple shims would take care of this.

As for the tracking adjustment, I don't feel that the addition of the 2 set screws is all that expensive or complicated.


On another note...
The Razor blades saw their first air on Thursday!
I only had time for 2 low passed down the runway, but everything felt very smooth, solid and promising!
Can't wait for more testing after Mentone!
Denis
 

XXavier

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How's the Magni tracking work Mike?


A good question, that... Mi Magni M24 was built in the first months of 2019, and the rotor head doesn't seem to have any... It has only the chordwise adjustment screw.

I e-mailed the Magni agent here, asking that, and he has just answered: there's no tracking adjustment in the Magni rotorhead. He says, however, that tightening the screws of the teeter block may work, to a point...
 

Smack

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This talk of chordwise adjustment makes me question what I thought I understood of the RFD (dang, hope I got THAT attribution right...) "slider" design. If I understood correctly, the blade assembly is allowed to find its own center, so "adjustment" was not necessary. Anyone able to confirm/clarify how the "slider" (mentioned also by Chuck B.) works?
Brian
 

XXavier

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A good question, that... Mi Magni M24 was built in the first months of 2019, and the rotor head doesn't seem to have any... It has only the chordwise adjustment screw.

I e-mailed the Magni agent here, asking that, and he has just answered: there's no tracking adjustment in the Magni rotorhead. He says, however, that tightening the screws of the teeter block may work, to a point...


I've just got an e-mail from Mike Goodrich, where he confirms that recent Magni rotors do have a tracking adjustment. He enclosed a photo. I examined recent photos of my Magni gyro and yes!!! There is indeed a tracking adjustment!!! Here it is... I was wrong, and Magni's agent in Spain was also wrong...

1145026
 

C. Beaty

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This talk of chordwise adjustment makes me question what I thought I understood of the RFD (dang, hope I got THAT attribution right...) "slider" design. If I understood correctly, the blade assembly is allowed to find its own center, so "adjustment" was not necessary. Anyone able to confirm/clarify how the "slider" (mentioned also by Chuck B.) works?
Brian
DW rotors are sufficiently uniform that a simple “stringing” before installation is all that is necessary to center the chordwise CG.

The intent of the “slider” is to raise the inplane resonant frequency of the rotor system above the aerodynamic exciting frequency of 1/rev when used with a stiff mast. The more rigid the mast, the lower the inplane resonant frequency.

If the inplane resonance is anywhere near 1/rev, the 2/rev shakes will be ever present. Rotor rotation doubles the observed shake frequency.
 

Resasi

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Well B’days and Sun n Fun were cancelled due COVID, Mentone has happened though Denis was unable to give his presentation on Razor Blades due social distancing concerns, but he had taken a number of rotor sets there for people to examine...and, if they wished, to try them before they purchased them. An offer I have not seen from any other manufacturer.

The process for the manufacture of these blades is a painstaking one and requires a number of stages that require precise and careful work. At every stage the care being taken, and the tracking of each component of the blades and batch of material they come from is precisely noted. I was involved in the construction of a set as part of the build process of the GT-VX2 912 single seater and was very impressed with the standards adhered to.

The rolls of adhesive require storage at low temperatures, and this is carefully monitored, they have a shelf life, and a life outside the low storage temps, which again is carefully noted. The adhesives that is prepared for a specific rotor set includes some for the test strip that will be included in the baking process and goes to the customer along with the rotors and the graph showing the times temps and pressures of the bonding process.

Each set of blades is balanced and tracked on the tracking rig, before then being test flown by Denis. The 25’ blades which were done for my GT-VX2 Explorer were test flown by Denis and because he knew I would be keen to see how they flew he was kind enough to video it for me.

They flew extremely smoothly and the absence of stick shake is very clear.


They have come a long way and at the moment a presentation is being prepared for the UK CAA/LAA together with putting together arrangements for a flight test with the CAA approved Test Pilot in the UK.
 
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PilotMark

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I talked with gyro technic on the phone about getting ahold of some of these blades. Very friendly. Seemed swamped with work (which seems like a good problem to have).

I was hoping some people of this forum would be able to help me choose a rotor diameter for my order. I'm building an ultralight star gyrobee powered by a 447. I myself weight 160 lbs. I'm trying to keep everything exactly as the assembly manual has it, as I'm not an engineer. The assembly manual makes recommendations for rotor blades based on brand:
23 feet for DW is adequate
24 feet sportcopter
24 to 25 feet skwheels
There's some other recommendations but it says 1.0 pounds per square foot is best to provide adequate climb performance.

So I'm hoping I could get someone who is more knowledgeable than me to wright in on what the diameter should be for razor blades?
 
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