MTO classic vs magni 16 trainer. In your opinions what really are the differences?

Thank you. All is forgiven. :giggle:

If by "Aluminum aircraft structures that were made with 2.0 x safety factor are flying around 50 years later" you were speaking of airplanes, I don't think such can be compared to a dynamically moving gyroplane mast. AutoGyro masts can crack elsewhere than the engine mount weldment. AutoGyro has a Service Information Letter about it: AG-SIL-2017-01-A-EN – Calidus frame upper mast side plate. I agree with you that their welding technique is to blame (albeit partially) after looking at photos of that new Calidus 83-AMW crash in France during take-off back in 2014.

It all depends. If you are going to make a mast stiff and provide no spread out point of release then the vibration will cause cycles concentrated in a spot that will fatigue. Anyway, Aluminum masts are not welded and changing them is more simple. Normally operated 304 Stainless of 14 gauge 2 inch square can last over 4000 hours+.
The Calidus upper mast plate weld that you are talking about is designed that it is more likely to crack. The bottom is longer and clamping points are 4 inches apart and the upper side welded is only 2.5 inches tall. They should be of about equal height. They will have a lot less chance of cracking and the plates should be welded with back purge inside upper mast tube. Anyway, that's AutoGyro's problem.
 
If you are going to make a mast stiff and provide no spread out point of release then the vibration will cause cycles concentrated in a spot that will fatigue.
Agree, as I posted: "a non-bushed stainless steel gyroplane mast not fatigue cracking after 20 years of ample flying would be a novelty, in my opinion." I would also blandly concur with your "Normally operated 304 Stainless of 14 gauge 2 inch square can last over 4000 hours+" if that tube were allowed full height limberness, but such is compromised by welding lateral mounts at mid-height. Your good point about the Calidus upper mast bracket asymmetry is another reason why I simply do not trust the engineering acumen of the "world market leader."
 
Agree, as I posted: "a non-bushed stainless steel gyroplane mast not fatigue cracking after 20 years of ample flying would be a novelty, in my opinion." I would also blandly concur with your "Normally operated 304 Stainless of 14 gauge 2 inch square can last over 4000 hours+" if that tube were allowed full height limberness, but such is compromised by welding lateral mounts at mid-height. Your good point about the Calidus upper mast bracket asymmetry is another reason why I simply do not trust the engineering acumen of the "world market leader."

You do know that a lot of the Calidus and Cavalon design and certification engineering was done in your country and not in Germany :)
 
You do know that a lot of the Calidus and Cavalon design and certification engineering was done in your country and not in Germany :)
A common feature of this discussion seems to be the use of square section tubing of SS or 4130. What about round section tubing of SS or 4130 with more mast length free of fixings which might be a node for failure? Manufactured gyros are so expensive now that a 20-year failure-free life for mast, keel etc., would be a must for whatever environment the gyro operates in or at least an easily replaceable mast. In salty damp environments, unseen internal rust in a 4130 tube is a bit scary. Would an easily replaceable round SS mast be a good compromise? John H.
 
A common feature of this discussion seems to be the use of square section tubing of SS or 4130. What about round section tubing of SS or 4130 with more mast length free of fixings which might be a node for failure? Manufactured gyros are so expensive now that a 20-year failure-free life for mast, keel etc., would be a must for whatever environment the gyro operates in or at least an easily replaceable mast. In salty damp environments, unseen internal rust in a 4130 tube is a bit scary. Would an easily replaceable round SS mast be a good compromise? John H.

We should only solve those problems that show a pattern of occurring. I agree about the mast/engine mount cracking being an issue on AG and the Calidus mid height mast plates being an issue but they are problems of welding technique (sugaring) and design. Not a problem of material or shape of the tube.
 
You do know that a lot of the Calidus and Cavalon design and certification engineering was done in your country and not in Germany :)
Yes, and as I posted previously, I don't understand how they got past our BCAR Section T, which I assumed was more stringent.

Abid, I'm not going to harp on your choice of SS 304, but I am skeptical of the "we cannot use 4130 because it requires a mill run in acceptable wall thickness" since Magni, Sportcopter, and Aviomania use 4130 in less than .125" wall. (.065 or .080, I don't know.) I'm also not quite buying the corrosion problem of 4130. Not in this day and age. You've made your choice in material, and thus you must defend it. I hope that you've no future cause for buyer's remorse.
 
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Hi Greg, I have a decision whether I go Magni or ELA for my next gyro. You posted that you were able to get 525 rotor rpm by pulling a tight turn. You noted that an MTO would not do this. In your Magni (M16?), how fast did the rotor rpm decay back to normal and typically what was normal rotor rpm for typical Magni flying? Very interested as the stresses in the mast might be different for 4130 type masts as compared to the ELA stainless steel, particularly with respect to fatigue failure. I guess there is always the question of which will fail first, 4130 due to internal rust in the mast or Stainless Steel due to fatigue / work hardening, hours and type of flying and sea side environment being equal. Is the Magni less prone to blade sailing? Would the Magni mast preform more robustly in a take-off tumble? Many thanks, John H
 
Yes, and as I posted previously, I don't understand how they got past our BCAR Section T, which I assumed was more stringent.

Abid, I'm not going to harp on your choice of SS 304, but I am skeptical of the "we cannot use 4130 because it requires a mill run in acceptable wall thickness" since Magni, Sportcopter, and Aviomania use 4130 in less than .125" wall. (.065 or .080, I don't know.) I'm also not quite buying the corrosion problem of 4130. Not in this day and age. You've made your choice in material, and thus you must defend it. I hope that you've no future cause for buyer's remorse.

You can buy and fly Magni. I am happy for you :). That's the open market.
Magni's 4130 tubing is not 2 x 2 sqaure tubing its more like 3 x 1.5 inch box and anyway they probably do do mill runs and keep tubing stock for long times.
I don't know which production SportCopter machine uses 4130? Is it SC-II? Well if so there are like 8 or 10 of them in the whole country and I don't think its produced regularly. I think all examples were made much earlier on.
You are welcome to not buy my concern with recreational flyers machines rusting of 4130. You don't have customers from 8 to 10 years ago in Punta Gorda, FL or Clearwater Beach hangers who fly seldom and the humidity oven (T hanger) remains closed for 6 months at a time and then you get to see what it looks like with boroscope inspection inside 8 years down the road. One way to alleviate that is to specify that all powder coat nicks and chips need to be fixed soon and insides need to be protected with Corrosion X treatment every 4 years but that isn't necessary with other materials. As long as a 12 pound hit is acceptable.
I just saw a 1000 hour AR-1 trainer with thousands of landings (I'd say 8 landings for each hour on average) and not all nice obviously. You know about the fatal accident of MTO Sport in Germany where the instructor had 4000 hours on his rotors and probably as many or more on his gyroplane frame. The 4000 hours was well past the rotor blade life limit and that caused the fatal crash but not the frame. These are training hours which produce a lot more cycles and abuse than a regular user. You can draw whatever logical conclusions you want from this. I do understand that with Stainless sugaring on the back side of the weld is a concern and that means the welding and purging has to be done more carefully. This is not an issue in 4130. Normalizing can be an issue with 4130 with higher than 0.120" wall thickness though.

BTW, just curious, you know this dude Kolibiri? Your arguments sound exactly the same as him on the material properties.
 
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I'm sure that 4130 can be inadequately prepped for corrosion, just as you're sure that SS 304 can be inadequately welded.

Normalizing can be an issue with 4130 with higher than 0.120" wall thickness though.
What's your point? Where would >0.120" wall 4130 ever be used on a gyroplane?

Interesting page; I do not know him. However, I would wager that others here do not believe in SS 304 for gyroplane masts. If I had the time I'd read all 11 pages of that thread to confirm my hunch. You can build SS 304 masts and sell such gyroplanes. I am happy for you :). That's the open market.
 
I'm sure that 4130 can be inadequately prepped for corrosion, just as you're sure that SS 304 can be inadequately welded.


What's your point? Where would >0.120" wall 4130 ever be used on a gyroplane?

Interesting page; I do not know him. However, I would wager that others here do not believe in SS 304 for gyroplane masts. If I had the time I'd read all 11 pages of that thread to confirm my hunch. You can build SS 304 masts and sell such gyroplanes. I am happy for you :). That's the open market.

Yup. I just thought you may have already read that thread. He complained that AR-1 at the time in 2018 does not have enough time on. Well now it has multiple examples with 1000 hours with no mast issue. One trainer with 8000 or so landings and takeoff cycles approximately. So there goes that point but I am sure the goal post will keep moving. Love/hate of material not an analysis based on engineering
 
Hi Greg, I have a decision whether I go Magni or ELA for my next gyro. You posted that you were able to get 525 rotor rpm by pulling a tight turn. You noted that an MTO would not do this. In your Magni (M16?), how fast did the rotor rpm decay back to normal and typically what was normal rotor rpm for typical Magni flying? Very interested as the stresses in the mast might be different for 4130 type masts as compared to the ELA stainless steel, particularly with respect to fatigue failure. I guess there is always the question of which will fail first, 4130 due to internal rust in the mast or Stainless Steel due to fatigue / work hardening, hours and type of flying and sea side environment being equal. Is the Magni less prone to blade sailing? Would the Magni mast preform more robustly in a take-off tumble? Many thanks, John H
In my opinion the Magni is more robust than the ELA, simply looking at the R head will tell this, I have flown and instructed on both, my opinion is an opinion and has no scientific data. Recently ELA reduced the wall thickness of there assembly, search this forum where I posted pics of a mast of ELA that collapsed on a hard landing. Breaking the pilots hand and writing off the new ELA.
I pulled 525 indicted Rrpm in a insane tight turn….(M16) with loads of power to add to the fun factor, was it clever? No! I was young pilot then less 1000 hours, I can’t say how long it took to decay back to the normal Rotor speed but be assured it’s was max a second or two.
As for your question what is the normal Rrpm this is a bit open ended as it will depend on the DA the MAUW, as rule of thumb at the coast I see around 330Rrpm / 350 odd in straight and level flight, with marginal increase in medium turns, I weigh in at average around 74kg and carry normally around 40l of gas
In the high veld where the DA is say 8000ft I will see rotor rpms in the high 300 and early 400Rrpm.
IMO I would not yank and bank with the ELA or the MTO like one can with the Magni, today I fly a carbon Xenon and I can pull off the same flight manoeuvres I do in the Magni, I just need to fly it with more finesse and more smooth inputs its not as robust as the CM built Magni
If your looking to buy you need to determine what you want from a machine ? If you have stunning smooth runways MTO ELA are fine …if you have questionable runways a Magni will be my choice.
There is a reason why Magni has such a great resale value over the other brands …I often wonder why?😁 I’m not saying it’s better than others I’m saying it’s just more robust and you really need to be ham fisted with the stick to damage it.

Im a pilot and I tinker with rebuilds and maintenance I’m not a materials expert these are my opinions only
 
Hi Greg,
Many thanks for your comprehensive and very informative reply. You have clarified many questions for me. I have flown an ELA07S for the last 5 years and am considering a change. I like open cockpit flying so I am looking at ELA07 / Cougar or Magni M16 /M22 as options. I have a few hours in a Magni M16 and and M24. I intend to do a few hours difference training with a local CFI in his Magni M16 to get a better feel for the differences between the ELA and the Magni, especially the Magni pre-rotation / take-off procedure. Many thanks for clarifying the 525 rotor rpm saga. Best regards, John H.
 
Abid, obviously, SS masted gyroplanes are not failing in flight with significant regularity. Good. But, they have occasionally failed (which you blame on poor welding technique vs. the material), and I know of no 4130 masts so failing. I neither "love" 4130 nor "hate" SS 304. (Some of my favourite objects are made of SS!) For me it's all about wise application. You yourself admitted that you'd have used 4130 for your masts if the preferred wall thickness did not require a special mill run and if there were no corrosion concerns. You will naturally retort that it was about 4130's far superior strength-to-weight. I believe that 4130 is a more "forgiving" and predictable steel for gyroplane masts, and that it can be very well protected against corrosion, but we shall have to agree to disagree on that.
 
Abid, obviously, SS masted gyroplanes are not failing in flight with significant regularity. Good. But, they have occasionally failed (which you blame on poor welding technique vs. the material), and I know of no 4130 masts so failing. I neither "love" 4130 nor "hate" SS 304. (Some of my favourite objects are made of SS!) For me it's all about wise application. You yourself admitted that you'd have used 4130 for your masts if the preferred wall thickness did not require a special mill run and if there were no corrosion concerns. You will naturally retort that it was about 4130's far superior strength-to-weight. I believe that 4130 is a more "forgiving" and predictable steel for gyroplane masts, and that it can be very well protected against corrosion, but we shall have to agree to disagree on that.
Not denying the veracity of the statement, just asking which accidents were the result of masts actually failing in flight? I was only aware of cracks detected, not actual failure in flight.
 
Not denying the veracity of the statement, just asking which accidents were the result of masts actually failing in flight? I was only aware of cracks detected, not actual failure in flight.

There was one in France. It was the second hour for a new frame for a Calidus. Failed right in takeoff low to the ground. Obviously in the second hour fatigue had nothing to do with it. It was welded wrong. We have fixed a couple of MTO Sport frames. It’s usually around the engine mounting. I do not care for the bent plate design versus tubes to hold the engine. Also know that there is no back purge on those welds into the mast. They do really good full frame electro polish but that shiny metal doesn’t do anything if you got oxygen exposure on a fully penetrated weld on the inside. It will fatigue pre-maturely. You do not have to do that with 4130.
Thee are a couple of accidents in ELA in flight where the tail lower keel broke off. I think France and Spain. Unlike MTO who bend tubing there, they actually butt weld cut tubing. Obviously butt weld has to be a fully penetrated weld. Again no back purge and evidence of sugaring was found by investigators. Plus no additional side plates welded. Since ELA has added plates around the butt welds for redundancy.

These are things figured out long time ago. FAA AC 43 tells you about sugaring and what should be done to avoid it in stainless steel aircraft components. DTA made a bush trike called Voyager that was Stainless Steel and it held up very well. AirCreation does a trike called Tanarg with Welded tubalar space frame from stainless steel. These have been around since 2003 and have had no problems. DTA JRo was also Stainless Steel. But they knew I believe in what to do with Stainless.
 
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And this is the problem with 4130. If the paint starts to chip off and you don't do timely maintenance to correct it, you can get rust and pre-mature fatiguing. I saw this same thing in our trikes but rust started from inside for a trike based at Clearwater, FL which is close to the ocean. Salt settled inside the tube and salt settled will rust and corrode anything specially any steel alloy. It was a 7 year old trike and the customer had never bothered to do any internal inspection or corrosion x treatments. Nothing.
 
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After the above fork failure strain gauges were fitted to the new fork to determine the stresses in flight and on the ground. Unfortunately during removal and refitting of the fork the nylock nuts were either not tightened sufficiently or reused.
My identical aircraft has these parts pinned...as required since that incident. Fresh correctly tightened nylocks should be fine.
 
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