Mini 500 forum ??

Honken

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attach two pictures of all parts that i think belong to mss upgrade - exept the blue coloured mast. it's more parts than one thinks.

the procedure to acomplish it, is complex too.
 

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Murdock

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try get in contact with both. these phonenumbers are 20 years old:
Hennie: 027825765166
David: 27832978270

this is quite funny, i have saved some of the info from hennies homepage, and what modifications he did. he mention both 618 and F30 so propably he put in 618 first, replaced it with F30 and nowaday it’s a turbine. these modifications are made by the builders themself and have nothing to do with rhci and their recomendations.

after hennie sold his m5, he proceed with other projects. david own majestic air, charter operator. info from internet.
Honken thank you for the great tip on the guy's numbers. I ran them on true caller and the one says Dave Maree and the other Hennie Roets. So ill definitely get in contact with them. I found two SOLAR-T62-2A1 Engines in the states but will have to save up and hustle to get one of them in lol!
https://www.ebay.com/itm/SOLAR-T62-...e=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649
 

Murdock

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try get in contact with both. these phonenumbers are 20 years old:
Hennie: 027825765166
David: 27832978270

this is quite funny, i have saved some of the info from hennies homepage, and what modifications he did. he mention both 618 and F30 so propably he put in 618 first, replaced it with F30 and nowaday it’s a turbine. these modifications are made by the builders themself and have nothing to do with rhci and their recomendations.

after hennie sold his m5, he proceed with other projects. david own majestic air, charter operator. info from internet.
The Rotax info screen is still installed inside ZU-BRA.
 

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Murdock

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The Centrifugal clutch does not need balanced. That was an AD before we know what was really making the vibration. We were kind of forced to grab at straws due to customer pressure when a bunch of them were saying it was unbalanced. It turned out to be the ridged belt tensioner pushing the clutch sideways from the torque pulsing of the engine. The solution came with the Mast Support kit fixed that with a spring-loaded idler arm.
So where would one acquire such a Mast Support kit or pics of it?
 

Murdock

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attach two pictures of all parts that i think belong to mss upgrade - exept the blue coloured mast. it's more parts than one thinks.

the procedure to acomplish it, is complex too.
Once I get the M5 ill take the GoPro and take pics of everything from the motor to the mast and ill upload them then you guys can see what has been done there.
 

Honken

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So where would one acquire such a Mast Support kit or pics of it?
Hi M
Mast Support System (mss), no one sells it. maybe it can be found on sites like ebay.

you must know that it was manufactured for more than 20 years ago, only 100 sets was made. there was totaly over 500 M5's kits sold. so for now, the zu-bra is a lost case, at least as a flying machine. don't buy it since you will only get disappointed (i'm disappointed too, but more on my local eaa chapter that denied me building it, even though they initially said it was ok "is it okay in us, then you can bring it in")

look at the two pictures i attached earlier, many parts that make up the mss upgrade.

there is a old thread in this forum from 2008, where mr fetters, wanted to produce a last batch of mss. assume, there where too few owners that wanted one.

the best advice is to import a M5 that have all modifications installed - if you really want a M5 that you can use. preferable one with a high serial number 400+.
 
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bugflyer

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Contact member Hawk on this forum. He is Rick Hawkinberry and was instrumental in the MH1 (a much imoproved M500 with Yamaha engine). He may know location of a mast upgrade.
smiles,
Charles
 

Honken

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remember, AD#092299 must also be done, but that one is easier. i attach the procedure. it require part #0047 and o-ring #0620
 

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Murdock

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Hi M
Mast Support System (mss), no one sells it. maybe it can be found on sites like ebay.

you must know that it was manufactured for more than 20 years ago, only 100 sets was made. there was totaly over 500 M5's kits sold. so for now, the zu-bra is a lost case, at least as a flying machine. don't buy it since you will only get disappointed (i'm disappointed too, but more on my local eaa chapter that denied me building it, even though they initially said it was ok "is it okay in us, then you can bring it in")

look at the two pictures i attached earlier, many parts that make up the mss upgrade.

there is a old thread in this forum from 2008, where mr fetters, wanted to produce a last batch of mss. assume, there where too few owners that wanted one.

the best advice is to import a M5 that have all modifications installed - if you really want a M5 that you can use. preferable one with a high serial number 400+
I hear what you saying Honken. I picked it up for cheap so I'm not to bumed out if it ends up hanging in my garage. But like i said lets see what is on there when I remove the covers and take pics.
 

Honken

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Honken thank you for the great tip on the guy's numbers. I ran them on true caller and the one says Dave Maree and the other Hennie Roets. So ill definitely get in contact with them. I found two SOLAR-T62-2A1 Engines in the states but will have to save up and hustle to get one of them in lol!
https://www.ebay.com/itm/SOLAR-T62-2A1-MOSQUITO-EXPERIMENTAL-HELICPTER-GAS-TURBINE-JET-ENGINE-95HP/224172854944?ssPageName=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649
Honken thank you for the great tip on the guy's numbers. I ran them on true caller and the one says Dave Maree and the other Hennie Roets. So ill definitely get in contact with them. I found two SOLAR-T62-2A1 Engines in the states but will have to save up and hustle to get one of them in lol!
https://www.ebay.com/itm/SOLAR-T62-2A1-MOSQUITO-EXPERIMENTAL-HELICPTER-GAS-TURBINE-JET-ENGINE-95HP/224172854944?ssPageName=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649
Honken thank you for the great tip on the guy's numbers. I ran them on true caller and the one says Dave Maree and the other Hennie Roets. So ill definitely get in contact with them. I found two SOLAR-T62-2A1 Engines in the states but will have to save up and hustle to get one of them in lol!
https://www.ebay.com/itm/SOLAR-T62-2A1-MOSQUITO-EXPERIMENTAL-HELICPTER-GAS-TURBINE-JET-ENGINE-95HP/224172854944?ssPageName=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649
Honken thank you for the great tip on the guy's numbers. I ran them on true caller and the one says Dave Maree and the other Hennie Roets. So ill definitely get in contact with them. I found two SOLAR-T62-2A1 Engines in the states but will have to save up and hustle to get one of them in lol!
https://www.ebay.com/itm/SOLAR-T62-2A1-MOSQUITO-EXPERIMENTAL-HELICPTER-GAS-TURBINE-JET-ENGINE-95HP/224172854944?ssPageName=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649
i found some old, still valid, info from 1995 regarding use of apu's - that could be of interrest.
 

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Honken

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i found some more info reg M5's in SA. it looks like a guy Anthony J. Martin in Linkhills, 3652, Natal. #2731773967, was a dealer, he bought maybe 5 kits. There could also be some mixup between the registers. Propably there can be around seven M5's in SA according to these registers from around 2001.

#0018 ZU-ATO A. J. Martin
#0072 no reg A. J. Martin
#0223 ZU-BRA David Maree
#0226 ZU-BRA David Maree
#0263 ZU-BCL A. j. Martin
#0264 ZU-BHC (ZU-AXO) Hennie Roets
#0265 ZU-BGN A. J. Martin
#0319 no reg A. J. Martin
 

Murdock

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i found some more info reg M5's in SA. it looks like a guy Anthony J. Martin in Linkhills, 3652, Natal. #2731773967, was a dealer, he bought maybe 5 kits. There could also be some mixup between the registers. Propably there can be around seven M5's in SA according to these registers from around 2001.

#0018 ZU-ATO A. J. Martin
#0072 no reg A. J. Martin
#0223 ZU-BRA David Maree
#0226 ZU-BRA David Maree
#0263 ZU-BCL A. j. Martin
#0264 ZU-BHC (ZU-AXO) Hennie Roets
#0265 ZU-BGN A. J. Martin
#0319 no reg A. J. Martin
I'll try and find his contact details. I found a T62 Unit complete here in SA. The guy who originally installed the T62 into the M5 has a spare. He bought 2 engines and fixed the one up and installed it into the M5.
 

Junglepilot

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I have a mini 500 turbine here in the USA for sale if anyone is interested. The reason for the vibrations in the mini 500 were not from any of the fixes like mast support or any of that it is due to the main blades the way they were formed they actually have a banana shape to them this was found out much later and only a few models have the fix to fly smoothly. My turbine mini 500 does have this upgrade.With the fix they can be tuned to perfection no vibration with no mast support ect basically they were not in alignment with each other this caused massive vibrations through the entire aircraft
 

DennisFetters

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I have a mini 500 turbine here in the USA for sale if anyone is interested. The reason for the vibrations in the mini 500 were not from any of the fixes like mast support or any of that it is due to the main blades the way they were formed they actually have a banana shape to them this was found out much later and only a few models have the fix to fly smoothly. My turbine mini 500 does have this upgrade.With the fix they can be tuned to perfection no vibration with no mast support ect basically they were not in alignment with each other this caused massive vibrations through the entire aircraft

Is that right? Well, I wish we would have known that to be the problem! ;-)

For those that would like to really know, here is are two Kitplane Magazine articles attached from Kin Armstrong, a very qualified helicopter pilot that flew the Mini-500 with all the mast Support updates and PEP system.

It seems to contradict everything you said. But, hey, not everyone was privy to the facts at the time and can only rely on rumors of what they may have heard.
 

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Junglepilot

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I am not knocking any of your upgrades. Or the pilots opinion. Just a fact on this machine does not have mast support and when blades are in perfect alignment to each other no vibrations smooth flying
 

DennisFetters

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I am not knocking any of your upgrades. Or the pilots opinion. Just a fact on this machine does not have mast support and when blades are in perfect alignment to each other no vibrations smooth flying
I have to agree with you..... on the modified Mini-500APU you have.

I looked at your pictures on the other thread for Mini-500 parts. I could immediately see what was done differently.

First, our problem ended up being a combination of design mistakes, each amplifying the other. I knew what to do to correct what was happening, but financially my hands were tied. The Airframes were one of the most expensive and time-consuming items to build, yet that was the main part of the problem, and to redesign it correctly, build all 400 (at that time) customers a new one, even if I sold it to them at my cost, would have put us out of business, and that was not in the best interest of the customer as well. No, I needed a solution that would forever solve the problem, yet would retrofit on what we had and cost as little as possible to produce. That was a butt-load of thinking, designing, and doing, but we did it.

1. For the normal Mini-500, we have an engine that vibrates, so it has to be isolated from the rest of the aircraft. For you, the vibration is not an issue, so you can have solid mounting and drive belts which will eliminate some "soft-spots" we had to have in the classic Mini-500.

2. The way I designed the frame where the Main transmission mounted was wrong in one place. It would allow the 1" horizontal tubes to bend, rather than to put that load into corners. You were able to place more bracing in the area to distribute that load since you didn’t need the idler pully and its mount.

3. The real problem came from the flexibility in that horizontal tube the transmission attached. If you take your fingers and squeezed the main drive belt together in the center, you would observe the rotorhead moving forward and aft, and that was not good.

4. With any semi-ridged two-blade rotor system, it is important that the teeter height of the system will intersect the Center of Mass of the blades during coning. In the beginning, we experimented with the height until we found the smoothest height. However, it was WRONG, and due to the frame allowing that slight flexibility, the misalignment between the teeter height and rotorblades Center of Mass (C of M) alignment during coning, would cause the mast to rock back and forth, radiating down into the frame and causing it to brake.

Now, if the frame would have been more ridge, that would have allowed for the proper teeter height to align with the rotorblades C of M during coning, and that vibration and mast rocking would be eliminated. That is what the mast support corrected, and that is why the mast support includes new teeter blocks at a shorter height so that they will align properly with the C of M of the main rotor system.

With your extra bracing, ridged belts, and more solid engine mounting, and putting blades on that matched the rotor systems C of M, effectively also solved the issue. With what you have, you could have still used the Mini-500 blades and changed the teeter height, and still fly very nice, without vibration.

As for the warp in the Mini-500 blades, this is due to holding the blades straight in the molds while in the oven curing at 250F, and once removed, the aluminum spar will shrink slightly more than the composites, and providing the blades with that slight bow. In reality, this positive load on the blades makes them more ridged.

Also, I did try making a set of blades with the molds warped in the oven, so when the blades came out, they were perfectly straight. Upon flight testing, I found that it took much more spring action to counteract the downward pull of the collective, yet there were no other benefits found from the flight testing. In action, the slight warp of the blades helped to reduce collective pressures.

A different manufactured blade force may react differently, but, this is what we had in the field and this is what we had to make work.

I respect anyone that can make a helicopter fly if it’s their own design, or 98% someone else’s design and they were able to toy around and make some improvements. The one thing I ask of them is to remember that it’s easy for them to come up with even radical modifications that make improvements, “one time”, while I was a manufacturer that already has 500 of the units in the field all over the world have my hand-tied in many ways, and my solutions are much more difficult to design and implement when needing to stay in a budget for yourself and the customer.

You have a beautiful Mini-500APU, one of the nicest I’ve seen.
 

Honken

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I think one should read the winter 1999 issue of "Reaching The Customer" to get a detailed explanation of 1& 2-per rev vibration. suppose that info is still valid.
 

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DennisFetters

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I think one should read the winter 1999 issue of "Reaching The Customer" to get a detailed explanation of 1& 2-per rev vibration. suppose that info is still valid.

Old information. This was before the Mast Support updates.

Attached is a copy out of the Mast Support Update manual;
 

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Honken

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okay. i thought it was othervise a great description of how you manage to track down the problem together with Norman Serrano.
 

DennisFetters

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okay. i thought it was othervise a great description of how you manage to track down the problem together with Norman Serrano.

Yes, it was. When Norm came to help us come up with a way for customers to manage rotor vibrations it was a great step forward, even for the kit-built rotorcraft industry as RHCI was the first factory to do so.

But, he helped us prier to the Mast Support updates. He was able to greatly improve the vibration levels, but since the mast was not stable, the vibration levels would fluctuate during flight.

After the Mast Support updates, by then I also was able to learn and understand the concepts of rotor vibration control. Because Norm deals with many different helicopters, he has to have a solution that fits many different helicopters. His solution was to fix vibration with counter-vibration, which is an excepted practice.

Over time I found up that was not the ideal solution, and elimination of the vibration is better and even easier for the customer to learn and practice.

For instance, Norn will use tracking to counter a heavy blade, which is like taking two hammers and banging them together. Yes, you no longer feel the vibration, but the destructive forces are still there. I always keep perfect tracking and balance the blade so the forces are now gone.

In hover balancing, I treat the rotor system like the tire on your car, by tracking the tire to run true and balanced.

Once in forward-flight, you will feel vibrations again, but this is no longer a balance issue, but a tracking issue, which is then corrected only by trim-tabs. The trim-tabs will not affect the hovering track, because they are too far inboard on the rotor system.
 
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