MTO Sport Info

[OzGyro]

Hi All

Just a link and some interesting info re an incident on the MTO Sport. Not sure if this info has been posted before, or if applies to any aircraft here in SA.

http://www.rotaryforum.com/forum/showthread.php?t=25047


Cheers
Darren

[johnht]

Being a very satisfied owner of a MT Sport, I have given serious thought to the ASRA's report.

The opening paragraph is interesting and leaves me with a couple of points to ponder:

By virtue of the fact that a 'student' is refferred to, leads me to speculate that this is not an experienced gyroplane pilot, and therefore there is the obvious possibility that all his/her actions may not be within the 'normal operational limits of the aircraft'. (I do of course 'speculate'!)

What is meant by "...the student moved the control stick to a rearward position to use airflow to reaccelerate the the rotor for another takeoff"? During normal 'stop-and-go' landing, one always has the stick in a fully rearward position, and the rotor RPM is allowed to decay to somewhere about or above 200rpm (which ensures blades rigidity, and minimises/prevents blade flap), the power is applied, brakes released and a normal takeoff follows. This we all do all the time without any problems.

Also: "There is no evidence to suggest that the student's technique in handling the stick was anything other than appropriate ...". Could the 'student' not possibly have allowed the rotor RPM to decay to somewhere quite below 200rpm, did not had the stick in the fully rearward position, and then have brought the stick back too quickly? If so this could easily result in the now insufficiently rigid rotor flexing down and nicking the prop and tail. Could a mistake not have been made??

I'm not therefore saying that clipping the prop and tail is not possible, but under normal operations, by appropriately trained, competent pilots, neither this type of incident nor blade flap should ever be an issue.

I also followed the thread on the Rotary Forum in which it has been stated that there has been some weld cracks associated with the MT's. IMHO with our knowledge of the (often) painful precision and dedication to detail and safety of the Europeans, I cannot believe that if one operates an aircraft within its design parameters, frame or other cracks will occur. However, should the plane be subjected to excessively hard landings or other abuse, who knows what may break?

It will be interesting to see what comes of the ASRA's investigation, and should they expose something that needs serious rectification, I'll certainly be one of the first to apply any mod to ensure my safety. Meantime, I'm going to enjoy careful flying!!

John
ZU-REB

[mak]

Johnht

I suggest you have a look at the discussions on the rotary forum. The Australian agent has confirmed a change in the rotor head? (angle / position) from the earlier versions to the later MTO Sport version that reduce the rotor clearance gap and are now considering a mod to change this. Rather follow the discussion yourselve as there might be a lot of speculation.

[johnht]

Hi Mak

I am following the RF thread, and hear what you're saying. I'm quite open to being convinced there's a problem and will, as I said, implement any mod the factory brings out without delay (I enjoy life!). However, irrespective of what may or may not be wrong, operating the machine within its normal parameters should not be problematic.

Have there been reports of other MTOS experiencing this problem?

Regards
John

ZU-REB

[FO Gyro]

Interesting topic. From Rotaryforum, looks like the Calidus rotor head used on the MT0 Sport is causing the problem.

John, I think you are right though, when doing a touch and go, why would the student let the stick go forward. Sounds to me like the rotor RPM was too low to begin with.

Without mentioning any specific gyro types, I've owned a gyro where the rotor could make contact with the rudder when allowed to bend down. If the correct technique was used for take-off, and during a touch and go, with the angle that rotors cone at when in autorotation, provided the RPM is sufficient, it wasn't a problem.

[t-bird]

What happened to the cracked mast issue on the MT’s ?
Was an AD issued ?

[johnht]

The "inquisitive bug" seemed to have bitten me - so I went and did an inspection on the rotor angles on my MTOS. (If someone can tell me how to post some pics, I would like to post them to provide some visual clarity.)

Let me anyway give some feedback on my findings which will hopefully encourage some good discussion. (1 below is based on fact; 2 involves some extrapolation and assumption.)

1. These measurements are with the blade stationary (obviously, or I'd probably have had some of my anatomy chopped off!)

a. With the stick fully back, I have a significant prop & rudder clearance - ~400mm.
b. If I now pull the blade down until the teeter limit is reached, I have +10mm prop clearance, and -50mm rudder (ie, potential chop off!)

2. Assuming the rotor was spinning at a normal pre-takoff speed of >=200rpm, the blades would be very rigid and thus not sagging.

a. Again with the stick fully back, there would be at least 400mm prop & rudder clearance as nothing would be pulling the blades further downward.
b. Assuming now that gyro is hurtling down a somewhat bumby, grass/gravel strip, I imagine for the (now rigid) blade to flex at least 400mm a most significant force would be required. I don't see this happening easily, though.
c. Assuming the rotor rpm is low, say 100 rpm. The rigidity of the blade is not yet sufficiently high, and I imagine a sudden change in stick position reawards may result in the blade flexing enough to cause a problem.
d. Another case would be that of a 'stop-and-go' landing. If one were for whatever reason not have the stick fully back when stopping, AND the rotor speed was ALLOWED to decay too much AND one pulled the stick back QUITE SWIFTLY, then I can well imagine the liklihood of the rotor blades pruning the prop and/or the rudder!

I'm going to have somebody take some pictures of my gyro tomorrow while I'm spinning the rotor and moving the stick into various positions to get an idea of the angles involved.

(Hope this makes some sense!)

John

ZU-REB

[FO Gyro]

T-bird, the conclusion was that the aircraft in question where this happened, were all gyro's used for instuction, that had incurred very heavy landings, and had been allowed to land almost vertically from around 10 feet above the runway. A CAA approved mod is available.

An email was circulated to all MT-03 owners drawing their attention to this matter. Apparently a similar issue was raised with two of the other two prominent gyro's in SA, the one in particular had a MPD (Maintenance Planning Data document) raised about this issue in the UK, but not for MT-03.

[t-bird]

Hi FO Gyro

Thanks for the info. I think that some of the first ELA’s had the same problem but is was corrected by an additional plates welded on the sides of the mast.

[FO Gyro]

I'm glad this has come out into the open. It doesn't matter what gyro type is being flown, all pilots should inspect the mast area as part of their preflights, as it is a potential weak area, especially if you are flying a gyro that you don't know.

[Gyronaut]

My money is on blade-flap by the student. Elsewhere here on microlighters I posted that my experience of the MTOS has been very/extremely positive and that the rotor system is relatively light so if you land, stick forward and bugger around, your rotor RPM decay's very quickly. The machine I flew didn't like to engage the pre-rotator while the rotor was turning so it becomes tempting to 'try' and chance it, stick back without adequate RPM. Beware, it has bitten me in another type of machine once and will never happen again. I dont know the Calidus head but if you have adequate RPM it will NOT happen in an MTOS.

[OzGyro]

Hi All

Okay I have no doubts given all the circumstances and specualtion that pilot error probably attributed to this incident (damn crazy ozzies), however I think the real issue here is safety. If you have a look at the photo on the US forum(Red MT) it clearly shows that there is no clearance between the rotor and vertical stabalizer, there is some speculation that a change in design may have taken place and this may be the cause. I would be very interested to see if there are any gyro's here in SA that have the same apparent problem. Has anyone spoken to the local SA dealer to get there feedback/take on the situation? I am certainly not MT bashing as all my hours flown in the SA have been in the MT Sport and I love them, however if there is a possible safety issue involved here, we all need to be made aware of it. As we all know these machines are flown extensively throughout this country and are also heavily involved in the training scene. Any knowledge that makes things safer for us all is always welcome in my world.

Cheers
Darren

[johnht]

Hi Darren

I had another look at the picture of the red MT on the Rotary Forum. Referring to the info I provided previously (point 1.b), I get about the same deflection IF I manually pull the rotor full to the rear. However, this is not a normal situation and can probably only cause a problem if one is operating quite significantly outside the normal operating paramentersa. As JetRanger said, the MT's controls are relatively light and they must be treated with due regard. Any abrupt backward force on the stick when the blades are not spinning fast enough will almost certainly result in the rudder / prop being 'pruned'. I'm certainly not concerned in the least with the design, but will be sure to manage the rotor as per the book!

I'm going to try uploading a pic or two to show what I found. Hope it works.

Regards
John

ZU-REB

Normal position of rotor with stick fuuly back

Rotor blade angle when stick fully back.JPG (46.14 KiB) Viewed 3485 times

Stick full back and manually pilling blade down

Rotor blade max rearward.JPG (34.36 KiB) Viewed 3485 times

[OzGyro]

Hi All

Just a couple of quick pics which clearly identify the different control rod setups on the MTO Sports. Might be something worth paying attention to. Big question is, how/if this will this affect the type compliance?

Cheers Darren

MTOSport_Early_Model.jpg (13.34 KiB) Viewed 3428 times

MTOSport_Late_Model.jpg (13.06 KiB) Viewed 3428 times

[johnht]

Hi All

There has been quite a bit of discussion on the Rotary Forum board on the apparent dangerous situation re the new MTOs (and I gather Calidus') rotor.( http://www.rotaryforum.com/forum/showthread.php?t=25047 )

I've concluded that if operated correctly, there is no chance of the rotor striking the prop, tail or ground when the stick is fully aft - ie with the rotor >=200rpm.

There is however a question around manual pre-rotation in the event the pre-rotator fails. Here I'm pretty sure the blades could strike the rudder unless great care and some precautionary measures are taken. I have no experience with manual pre-rotation at all, but I will be approaching Theuns and Roelf for their opinions.

Happy and safe flying!
John

ZU-REB