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Old Jul 17, 2011, 11:11 PM
efflux RC's Avatar
United States, CA, Santa Clarita
Joined Aug 2009
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Quote:
Originally Posted by JimDrew View Post
Now, if we could just get the AMA to allow these rotors...
Yes, I'm still waiting Jim.

Conversely, We've been shipping the 70mm units to Canada, Australia, Europe, other places world wide........as well as "cornfield" USA.
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Old Jul 17, 2011, 11:23 PM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
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AMA needs to clear these ...i think there safer than plastic blades....i mean your FOD vid clearly shows these are well made.
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Old Jul 17, 2011, 11:44 PM
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LuvEvolution7's Avatar
St.Catharines, Ontario
Joined Jan 2009
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deffinitely. we know that MAAC up here in Canada has no issues with these fans, so not sure why the AMA wouldn't/couldn't follow suit. the only thing MAAC has an issue with, is unshrouded metal blades, which totally clears these fans for use up here. I hope this gets settled quickly, with a positive result, because as we know, the safety factor is superior to a plastic blade, no matter what material it's mixed with.
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Old Jul 18, 2011, 12:28 AM
efflux RC's Avatar
United States, CA, Santa Clarita
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This is the actual rule from the AMA Aircraft Safety Code (1/1/2011) that folks are concerned with. Note that there is a provisional allowance for metal bladed, large (20+ lbs) model helicopters.


2. Model aircraft pilots will:


"2. (G)
Not operate aircraft with metal-blade propellers or with gaseous boosts except for helicopters operated under the provisions of AMA Document #555."
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Old Jul 18, 2011, 12:31 AM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
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well then ...these are'nt propellers
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Old Jul 18, 2011, 12:41 AM
efflux RC's Avatar
United States, CA, Santa Clarita
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Yes, but look At the Heli document, allowing metal rotor blades there is no mention of manufacuring, personal safety or quality criterea.

The only provision is that you maintain a flight log, and inspect the rotor blades.

Inspect it with what? Your bare eyes?....... Flourescent inspection dye?

The helis all weigh over 20lbs as well. Hmm how close to use do we usually fly our helis.
................................


Anyway this is futile because the issue is not with the quality of our product. It is with how to regulate infereior manufactured copies/clones, or other similar EDFs by other mfgrs.
The AMA figured out how to deal with the metal heli rotors. They should be able to make some provisions for us as well.
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Old Jul 18, 2011, 01:13 AM
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Tamjets's Avatar
San Jose, CA
Joined Jun 2006
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Quote:
Originally Posted by AIR SALLY View Post
AMA needs to clear these ...i think there safer than plastic blades....i mean your FOD vid clearly shows these are well made.
You guys miss the most important of fan failure.
Motor bearing can fail, motor rotor can fail. One of the two failure will lock up the motor.
The rotor will fly off from the shaft and been metal rotor. The engergy of impact something and will continue bounce off and kept going until it stop. That does a lot of damage and could posible kill some one near it.
Plastic rotor or carbon rotor all more safe in this situtation. When it come of from the motor shaft. The first impact and it will destroy itself.
That reduce the engergy and likely not goes far out with light weight small pieces.
That why AMA not allow metal prop.
They had doing alot of safety homworks for insurance coverage. and
thinking of safety outside the envelope.

Just my .02 cent
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Old Jul 18, 2011, 01:49 AM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
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where do all the plastic parts fly off too? ...just as dangerous ,how many motors you seen lock up ...i had a glow motor back in the day do that ,i never had a bering faliure yet with EDF just my .02 $ im sure the AMA will work on this ....after all turbines have metal rotors .....worst case we get a EDF wavier.
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Old Jul 18, 2011, 02:06 AM
Xtreme Power Systems
Lake Havasu, AZ
Joined Jun 2005
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Tam is right. When I chatted with the AMA about this subject, it was the fact that the rotor can come off and exit out through the inlet ducting - potentially killing someone. The plastic parts just blow up (lots of experience with that myself!)

Perhaps if we have some sort of "X" made from high tensil strength wire on the front side of the fan assembly to prevent the rotor from being able to fly away, we might get this passed.
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Old Jul 18, 2011, 02:27 AM
efflux RC's Avatar
United States, CA, Santa Clarita
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Quote:
Originally Posted by JimDrew View Post
Tam is right. When I chatted with the AMA about this subject, it was the fact that the rotor can come off and exit out through the inlet ducting - potentially killing someone. The plastic parts just blow up (lots of experience with that myself!)

Perhaps if we have some sort of "X" made from high tensil strength wire on the front side of the fan assembly to prevent the rotor from being able to fly away, we might get this passed.
Who did you speak with Jim?
No one at the AMA conveyed this concern to me whatsoever.

I'll keep the "X" in mind.
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Old Jul 18, 2011, 02:38 AM
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San Jose, CA
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Quote:
Originally Posted by AIR SALLY View Post
where do all the plastic parts fly off too? ...just as dangerous ,how many motors you seen lock up ...i had a glow motor back in the day do that ,i never had a bering faliure yet with EDF just my .02 $ im sure the AMA will work on this ....after all turbines have metal rotors .....worst case we get a EDF wavier.

Turbine is really safe. When bladed shed off and it all contain in the can reduce it energy before spit out the tail.


How many motor I had see fail? Average service 4-6 bearing failure or rotor failure a year. I goes through enough fan sale and do see this happen on regular basic. Another parts of rotor flew off from the shaft can also be user not proper install. There is a lot peoples out there messing around with fan and had no skills of mechanical at all.Rmember I had one fail during bench testing couple yearsback.
The energy of the rotor flew off cut 1/8 through the safety glass before it shed to pieces.
Just imagine that is metal rotor.
The rotor bounce off and travel good distance before come to the stop.

Carbon and plastic rotor is dangerous as anythings else when failure happen.
But at least doesn't bounce off on impact and that alone can reduce a lot of risk.
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Old Jul 18, 2011, 08:31 AM
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St.Catharines, Ontario
Joined Jan 2009
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perhaps the answer to the problem IS self containment. lots of turbofans get passed with only axial containment and we're talking about a hell of a lot more people than would be around an EDF or turbine, but I digress............

perhaps it would be in Mach's best interest (and yours Gary) to look into TOTAL self containment in the event of a catastrophic failure of the rotating assembly. what is in my mind, is something similar to the WM400 arrangement. it wouldn't be very difficult for Mach to machine a piece that attaches to the front, that has three vanes (or however many), that attach to the outer annular shroud. this would contain any forward failure of the rotor and limit it to shrapnel, which would dissipate energy faster anyway. the rear is already protected by the stator assembly, so no worries there. with a front piece, the stators and the alloy shroud, you are talking about total containment. of course, you could also wrap the outer shroud with a single layer of Kevlar and there's no way a blade would go further than penetration of the composite sandwich. just my .02
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Old Jul 18, 2011, 09:33 AM
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United States, TX, Grand Prairie
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Quote:
Originally Posted by AIR SALLY View Post
where do all the plastic parts fly off too? ...just as dangerous...
I would position that the plastic rotors are MORE dangerous, I've seen some grenade from pieces of paper in miliseconds as well as the blades go through the shrouds.

I haven't seen this fans FOD experiment but I'd waver that it wouldn't grenade from pieces of paper at high speeds...

13pds from a 90mm fan...

I've got a couple of foamies that need a little bit more speed (jus a lil bit)
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Old Jul 18, 2011, 09:48 AM
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St.Catharines, Ontario
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there's footage of them throwing pretty much everything but the kitchen sink through the 70mm and it merely slows down for a split second. I would say that constitutes as LESS dangerous. LOL.
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Old Jul 18, 2011, 10:38 AM
turbonut's Avatar
upland CA
Joined Dec 2004
7,162 Posts
...never mind...dont want to get into this one
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