Thread Tools
Dec 07, 2010, 08:27 AM
Jets fly goooood!
felix72's Avatar
Thread OP
Discussion

E-Ducted Fan Outrunner Concept


Hi all,

I was surfing the net and came across this site:
http://www.lange-aviation.com/htm/en...tml#engine_xxl

The picture of the motor with the propeller's blade attached on the outside of the rotating case, make me think on how to explain the way I would like to see an outrunner applied to a ducted fan!
Yes I know, its strange...but I couldn't stop the crazy engineer inside of me!

If the rotor blades attachment system of a fan like the Dynamax could be modified to be used the same way, I believe some benefit will arise.

I actually wonder why all the manufacturers, like Sapac or XPS just to name a couple, that blame to use outrunner motor in their E-Fan interpretation due to higher torque, didn't go with a more radical way like this! Most of them went the easy way but at the end they still needed lot of modifications for their products to be good.

The new Sapac system for example is gonna use the new Scorpion 5035-xx motor. I am not knocking Sapac's product, I actually like their system because I think its introducing some improvement, but being a new system one could expect something more.
Again, not because their system is bad, far from me to say that, but its probably just a better re-interpretation of an old concept, actually the same concept that many used to mod the Dynamax.

I don't have enough pictures to sustain my thoughts about it, but for what they claim the motor is mounted closed to the rotor (not hanging that far back like others outrunner modification) and this is a good thing but of course implies some work on the central hub to make it shorter.
Moreover Sapac offer cut-down rotors of the Dynamax in their 100 mm version and that implies other work to be done.

Yes the diameter of the 5035-xx is larger then the Dynamax rotor central hub, so in this particular application its not suited, but I believe that nowadays isn't that difficult to ask company like Scorpion to customize an outrunner to match the dimension needed!

On the other hand some other manufacturer like Dyn-E-Max engineered and produce beautiful and expensive CNC aluminum parts to modify the Dynamax to make it become an excellent product...when available!!!

So it looks to me that manufacturers are more and more taking the route to heavily modifying the original Dynamax fan, either by adding expensive CNC parts, by producing cut-down rotors, by engineering modified hub to allow a better motor/bearings position, but the beef is still the same and is what everybody use...the original rotor-stator combination!

But why no one just make the engineering a step further and develop a whole more interact system? Look all the work they have already done to make their modified Dynamax products!

The Dynamax has already proved how good it is in performance since many are using it in their E-conversions, but now what I feel is needed is a more efficient and better-overall thought interpretation.
In my point of view this could be the breakthrough in E-Dynamax interpretation and it could be lighter, more compact, more efficient.

Anyone wants to call me crazy is welcome

Gianluca
Last edited by felix72; Dec 07, 2010 at 09:05 AM.
Sign up now
to remove ads between posts
Dec 07, 2010, 09:13 AM
EDF all the way!
bruff's Avatar
Hoffman motors already did it in their fan.
Bob
Dec 07, 2010, 09:17 AM
James L
TANGOSIERRAROM's Avatar
WHy not go the whole hog and put the windings in the duct casing and magnets on the rotor tips and voila a motor with a fan in the middle.
Dec 07, 2010, 09:18 AM
Jets fly goooood!
felix72's Avatar
Thread OP
Quote:
Originally Posted by bruff
Hoffman motors already did it in their fan.
Bob
Hi Bob,

do you have links for that?
What fan's size? Not on Dynamax size right?

Gianluca
Dec 07, 2010, 09:23 AM
Registered User
kimhey's Avatar
Quote:
Originally Posted by TANGOSIERRAROM
WHy not go the whole hog and put the windings in the duct casing and magnets on the rotor tips and voila a motor with a fan in the middle.
Not a problem cooling the motor that way
Dec 07, 2010, 11:09 AM
EDF all the way!
bruff's Avatar
Quote:
Originally Posted by felix72
Hi Bob,

do you have links for that?
What fan's size? Not on Dynamax size right?

Gianluca
No 70mm I think.
Bob
Dec 07, 2010, 11:44 AM
James L
TANGOSIERRAROM's Avatar
You could take a standard outrunner and bolt the rotor to the rear of the casing and mount the other end
Dec 07, 2010, 05:13 PM
Jets fly goooood!
felix72's Avatar
Thread OP
Ok,

I got the point Bruff was telling me.
I have seen that even most of the Computer CPU's fan are made like that, so...

Why nobody is using this method on bigger fan like the Dynamax?

Gianluca
Dec 07, 2010, 05:18 PM
EDF all the way!
bruff's Avatar
Damage a fan blade need a new assembly. No replacement parts.
Bob
Dec 07, 2010, 05:40 PM
Jets fly goooood!
felix72's Avatar
Thread OP
Well...

it depends on how the fan's blade assembly is engineered with the motor!
I have a couple of idea in which the rotor will remain almost the same, with the same clamp style of the rotor's blades, but the motor is part of the central hub even remaining independent.

I would agree with you if the rotor-motor assembly was one only piece, in this case its not practical at all, every time you need to replace a blade you need a new central assembly!!!

Gianluca
Dec 07, 2010, 05:49 PM
EDF all the way!
bruff's Avatar
I think Stu(Stumax)was looking at this this type of design for his fans. He went conventional design route. Forgot what the issues were.
Bob
Dec 07, 2010, 11:11 PM
Flying!!! Got to love it
raido56's Avatar
airborne-models.com has a 70mm fan that the rotor is mounted right to the motor can and works real nice. It has a lip on the back of the can and 3 bolts to hold it in place.

Keep em flying
raido56/ Herb
Dec 08, 2010, 03:13 AM
Closed Account

Let set the record stright


First of all SAPAC did not development the Dynamax EDF. I did the development work for Mike almost from the beginning. The 100 mm fan I did the orginal development of cutting down the rotors back in the late 80's when the fan came out. It was powered with an OS 46VFDF. Anybody can cut down a rotor. It can be done with a drill press and a file if your stupid enough to go tha way. To my knowledge, I been the only one that has
modified the Dynamax blade to cut down the number of blades on the hub. I have also gone the other way and made a rotor with 20 blades. It kinda irk's me to see someone on here say something that is distorted, because they don't really know what there talking about. If you don't believe me just do a search on here and enlighten yourself. By the way, the concept your talking about has been kicked around. The problem is the investment required is greater than the return.

My 2 cents worth

Larry Epifanio ( Yea I'm Itallian too, actually Sicillian)
SouthEast Model Products
Dec 08, 2010, 04:04 AM
Jets fly goooood!
felix72's Avatar
Thread OP
Hi Larry,

nice to get in contact with you italian on here!
I feel a little bit of anger in your words and in the way you speak, I ask you forgiveness if something that I said make you react like that.
You might be right when you say I am ignoring what the past was, in someway that's why I am here...to ask and understand!

If I am giving credit to Mike for the Sapac branded Dynamax conversion, its not my fault, its just what I read in his website.
As a possible customer I look around and see what the market propose, its the one how sell the stuff that has to advertise them properly and declare how the things really are, how developed what and so on...if there was a kind of agreement between you and Mike about that!

Nothing better then to declare in his site who actually made the modification to provide the finished product, if this is the case, but I don't see how this can be a reason to blame people on this thread, to me it looks like something more regarding you and Mike directly!

Larry...from my point of view you are very welcome to talk and describe whatever your work on the modified Dynamax was, if you are allowed to...
sometimes copyright apply!
The reason I say this is because the information about the Sapac Dynamax are a little bit unclear. I already asked more information and more pictures to see and demonstrate what the advantage they claim about the version of Dynamax, but nothing came out yet!

And you can't imagine how curious I am regarding your direct experience and knowledge for what you did.

That said, I hope you can post pictures regarding your modification and your experience, whatever is interesting to see, you can post them here if you like to do so! Or send the picture to my email or PM me to clarify.

Maybe I think things easier then what they actually are, but I also believe that the investment ALREADY made behind the available Sapac or whatever E-Dynamax conversion you want to name, has been considerable!
My only curiosity is, if this concept I showed has already been around for some times applied to smaller fan, why it has not been used for the latest E-Dynamax interpretation?

Gianluca


Quick Reply
Message:

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
For Sale 70mm Shulman Aviation Aluminum Electric Ducted Fan Package Fan/Motor viperjody Aircraft - Electric - Jets (FS/W) 6 Dec 12, 2010 05:42 PM
Sold E-Flight BL 15 Ducted Fan Motor, 3600kv And E-Flight Delta-V 15 Ducted Fan, 69mm RCFlyingForLife Aircraft - Electric - Power Systems (FS/W) 12 Nov 09, 2010 10:08 PM
Wanted WANTED A starter wand for a Byron Ducted Fan F-16 with the Dynamax fan, mechengineer03 Aircraft - Fuel - Jets (FS/W) 1 Oct 12, 2010 01:41 PM
Sold Concept X Super Performance Brushless Ducted Fan RC Jet RTF pulsery2k1 Aircraft - Electric - Jets (FS/W) 3 Oct 07, 2010 09:19 PM
For Sale Two BL420 Ducted Fan Outrunner, 3800Kv by E-flite $70 Shipped Todd Long Aircraft - Electric - Jets (FS/W) 0 Feb 18, 2009 02:23 PM