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Old Aug 06, 2010, 02:46 PM
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Originally Posted by GryphonRCU View Post
PeteB,

I hope you are not going to step down in quality and power from MEGA 16/25/2 and run an ARC 28-47-X.and spend extra money doing it.

Maybe there are misunderstandings going on here by me, you, or others.


Be 100% clear on this, the MEGA will handle more power and stay together.


The KV is different so you will just run different size prop to fly at same speed as ARC.....or increase prop size and leave the ARC in your dust.

While ARC is falling behind it will either sizzle and let out smoke or puke its guts out of the end cap coming lose or bend its shaft much easier in comparison during landing.

Want max out of your MEGA; run it on 5S


Your 100A ESC is perfect match in every way for your motor.

________________________

Also NEU bought out part of Medusa and can do service/repair for your Medusa motor in future.
Gryphon
Thanks, Gryphon! I had purchased the Mega based on the feedback I received from you and others in the Stryker thread on RCU back in in 2007 or so, but once the Stryker was totaled I didn't replace it at the time. Just received my Fly RC Mag the other day and saw the FJ Ultra and decided I'd like to get one. Glad to see the Mega is still a top contender in this area.

Thanks for the info. on Neu picking up the Medusa motors, I was not aware of that.

Now I have to decide whether I start with the Medusa or the Mega to work my way up to the speed....

Anyone know if a 5s pack is an easy fit in the FJ Ultra?
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Old Aug 06, 2010, 04:08 PM
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Quote:
Originally Posted by PeteB View Post
Anyone know if a 5s pack is an easy fit in the FJ Ultra?
No . Just dremmel a little the sides of the fuselage if you decide to put it horizontally

Please test the mega motor , we need data
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Old Aug 06, 2010, 05:54 PM
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petranf,

Not that you were wrong in asking for proof....but I didn't like it (just being honest with you).

I hope I don't have to post pics of ARC guts which have been misplaced.

Here is a video from my friend, he was smart enough to use throttle control. Since you are generating more heat than him due to your higher resistance in your motor (even though your KV is higher); I hope you are also using throttle control. After all Funjets have poor cooling airflow to motor.

Spirit models is not the place to get MEGA information. His info does not match manufacturer web site and MEGA rates the motors VERY VERY conservatively anyway.

My friends and I push the 480 motors (16/25/X) up to 2 1/2+ times the AMP rating in Strykers and they last when done correctly. I wouldn’t push that far in a Funjet but then again Funjets do not need as many Watts to fly fast/faster.


***Still trying to figure out WHY ARC motors have that groove on a 3.2mm shaft....that groove makes the weakest part of shaft under 3.2mm????? Anyone knows?


Multiplex Funjet on 5s 145-155 mph (3 min 19 sec)



When recommending motors we need to be careful that we know exactly what we are talking about and that we fully understand the question and parts already on hand.


*** I don't want to identify the props in my test below because the battery used was way too big for this motor....since it held much higher volts under load all of the props turned faster and drew more AMPs. People should test with their own battery.
In a Stryker we run up to low 90A range with 1:1 prop diameter to pitch ratio so it does not unload much at all, motor never gets hot......I would be more conservative in a Funjet due to available airflow to cool motor.

Due to this MEGA's lower KV and larger prop than ARC 1.5, the prop efficiency will also be higher, not just motor efficiency.
16mm is the diameter of rotor.
25mm is the length of the rotor.
Resistance value of 0.0075 Ohm 1 phase
Size and weight of motor is about same as ARC.
These days almost everyone is buying the 5mm COMBAT shaft at no extra cost.

Gryphon
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Old Aug 07, 2010, 02:02 AM
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Not that you were wrong in asking for proof....but I didn't like it (just being honest with you).
...MEGA rates the motors VERY VERY conservatively anyway.
My friends and I push the 480 motors (16/25/X) up to 2 1/2+ times the AMP rating in Strykers and they last when done correctly.
Gryphon,
i didnt mean disrespect...maybe i should rephraze. I didnt dought what you claim, i just asked some more info about mega performance. The fact that the manufacturer places sooo low the motor capabilities was a reason of non purchase. I am glad that it can bare a lot more.


I hope you are also using throttle control. After all Funjets have poor cooling airflow to motor.
Yes ofcourse. I fly like your buddy. Also i opened extra air ducts and heatsink at the motor.

***Still trying to figure out WHY ARC motors have that groove on a 3.2mm shaft....that groove makes the weakest part of shaft under 3.2mm????? Anyone knows?
I dont get what you mean. Both motors have same shaft.I feel that the shaft should be larger, but havent had an issue with this motor. What is scary for me is the bigger motors like 28-57-x with a 3.2 mm diameter shaft.
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Old Aug 07, 2010, 03:51 AM
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petranf,

Both motors have 3.2mm shaft. You are right. but look at the picture.


See that groove?

If shaft is 3.2mm, and then you have a part of it with a groove in it, then that part is no longer 3.2mm....RIGHT?

Since part of a shaft is smaller than 3.2mm, then that would be a weak point/failure point.

Depending on people's budget and requirements I have recommended many ARC motors (and still do) but things like that is just seriously bad engineering.
I really hope they redo that area and get rid of that groove.....since it is still a money maker at 50% replacement warranty; the chances of that redesign happening is low.

I don't look inside motors but multiple sources who do that kind of stuff are amazed to see that and have sent me pics.


Use brake and look to see position of stopped prop and bump it if needed before landing with prop in horizontal position (as long as non vertical) since you are at risk. At very least your props will last longer besides not bending a shaft.
(The two motors do not have the same shaft hardness).


Since you are reporting 135 MPH, I now you are being 100% fair in everyone's book.


Good luck with your flights,


Gryphon
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Old Aug 07, 2010, 04:19 AM
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ahhaaa. deam this is stupid. Thank god i put prop horizontaly before landing
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Old Aug 09, 2010, 03:54 PM
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Some like it hot ...

Still easy to handlauch and capable of speeds well over 150mph:
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Old Aug 09, 2010, 03:59 PM
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Originally Posted by Jurgen Heilig View Post
Still easy to handlauch and capable of speeds well over 150mph:

THAT looks nuts !!!.....
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Old Aug 09, 2010, 04:31 PM
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Jurgen,
that is an interesting project.Looking forward for video.
What is the total weight and the motor brand?

Is there any mini smoke sytem to install? It could be very useful since the plane is so small.

I suggest that you installed hinges and check the turbine mounting.

Good luck for maiden
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Old Aug 09, 2010, 06:05 PM
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It looks similar to the Kolibri turbine, http://www.lambert-modellturbinen.de/html/english.html
Not cheap, but nice!
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Old Aug 09, 2010, 06:50 PM
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Quote:
Originally Posted by Jurgen Heilig View Post
Still easy to hand lauch and capable of speeds well over 150mph:


Awesome post/pic Jurgen.

It looks like it is going MACH 1 while just sitting there.


Thanks,


Gryphon
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Old Aug 09, 2010, 11:37 PM
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Got mine to go 173km clock on eagletree airspeed indicator.
My setup is
HET 2W25 2700kv
4S 2500 lipo
4.5x4.1 @50amps ~700watts

My initial flight on this motor was on 5.5x4.5 that got me 75amps ~ 1kw which is much faster although I did not fit the airspeed indicator then.

My question to MPX is why in the world they made the ultra grey color? Against an overcast sky and it eating up the sky so fast I loose orientation real quick.
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Old Aug 10, 2010, 07:49 AM
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Chiadennis, i have an idea regarding the coloring. Epp is not easy to paint so i thought i could spray it with a gun with one layer of 24hours resin thinned with alcohol. This will be the base of the final paint or resin can be mixed with a coloring substance. I am a lazy this period of time cause it is summer but soon i will give it a try.
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Old Aug 10, 2010, 08:51 AM
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I can't wait till this thing is out in the USA.
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Old Aug 16, 2010, 04:25 AM
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Is it still not available at other continents ? Deam these guys dont want to sell? Maybe they are waiting until the chinese will copy the material properties

I am curious ... how much is the post charge from EU to USA for example?
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