Hi Gang
    I think ive finally given up on Rapier planes for a while, no L2s ..unreliable L3s, and damp squib L1s have all conspired against me, so until the problems get sorted , im givng up.  
 
Having said that , seeing Martys, EDF BV212 zipping around the skies in Geneseo, has inspired me somewhat , so im going to give it a go.  
 
For plane im using an EB Supermarine Swift, with a KP brushless fan , ill be using the KP timer, with a Feigao brushless ESC, and either 2 atomic Lipo cells or a 2 cell common sense lipo.  
 
The fuslegage is already half built and ill be mounting the fan this weekend ., ill be putting in a hatch for battery forward , and have the motor accessible with magnets holding the rear of the fuselage on.  
 
Ive also found a neat website    
 
www.bsdmicrorc.com
 
This guy does lots of electric stuff and fans and motors if you are interested. if anyone else is going to have a go at this genre ..maybe we can swap notes , im an old dog and this is a very new trick ..
 
All the best  
 
Paul

Quote from McDog on Jul 24^th 2009, 5:07am:

 
When we talked I explained the use of a GWS 31MM fan unit with Bob Selman brushless EDF motor.  
 
I like Derek's controller, it's the brain of my brushless system however I have no experience with his new 32MM brushless fan assembly and Losi (I think)motor. From the unit Campbell showed I have concern it's too large and worse very heavy.  
 
If you proceed with the K&P 32MM you are stepping into uncharted waters.  
 
Please email and I will explain the complete set of hardware again.  
 
Marty

Paul:
 
I only want you to be successful. EDF is not magic but like all propulsion systems needs to be right sized for their thrust and installed weight. If you like I’ll test that fan unit and find a LiPo combination to support it. My immediate impression is it needs an airframe the size of my 150% Flitzer.  
 
Regarding the Hunter and K&P44 brushed fan unit. I conducted similar testing and reported it here: http://www.jetex.org/scripts/yabb2/nph-YaBB.pl?num=1172943580/15, thread #25. The Zombie is too small but the Smoothie is adequate. One important modification to the kit is to engineer for fan removal.  

Ok here we go some clarification:
 
K&P44 is a brushed motor, needs a larger than Zombie controller, Smoothie brushed motor controller works.  
 
GWS31MM and K&P32 are brushless and use the K&P controller PLUS an ESC. I use the smaller YGE4-BL (4AMP) ESC but its rare now and I suspect the slightly larger, much cheaper Fiageo (6AMP) will work fine.  
 
Again I’ve not tested the K&P32 against my criteria for FF use so do not know what size LiPos it needs.  
 

Guys,
I dont own one of the KP 32mm fans but I have a had a close look at one. The motor appears to be a Feigeo 5800kv: http://www.espritmodel.com/index.asp?PageAction=VIEWPROD&ProdID=5130
 
The motor on it's own is 17g, I guess the complete unit less intake tube will be about 25g or so.. This is quite heavy for our purposes but I'm sure it's still doable.  
 
The motor is speced at 5.5A but with only a small fan to spin it probably wont see full current draw. The RC boys run these motors on 3 Lipo cells but the motor is only officially rated for 2 cells. I have one of these motors fitted to a GWS EDF 40 and it really screems on three cells (about 150g thrust).. but rather heavy for free flight use due to the size off battery required.
 
To achieve the 5.5A current rating you would need batteries of about 300mAh and 20C discharge rate.. (or perhaps 250mAh and 25C if you can find them).
 
Steve

Quote from copbait73 on Jul 26^th 2009, 3:36am:

Marty,
Yes, sorry for dragging my heels on sending the fan unit to you. I'll get it shipped when I get back home later this week.
 
Steve

Quote:

 
Paul,
 
When I read this question it made me realise just how stupid I can be sometimes!
I have had the same question in mind but have not had the presence of mind to ask it ... even though I talked to Derek Knight last Sunday!
Not quite so stupid I suppose as I have seen Derek make many successful EDF flights this year with what I have assumed to be this power unit in the models ... but I should have confirmed it by now.
The unit can be made to produce up to 130g of thrust so it obviously will be best suited to 'larger than rapier' models.
Here are some of Derek's EDF models - they are all 'significantly larger' than rapier L2 models, but of similar size to Mike Stuart's L3 powered 'big' Tunnan.
His MIG has been flying for some time now but seems to perform very reliably lately ... perhaps upgraded to the new unit?

His Nats winning Baroudeur - I'm sure that this is the size of model the unit is intended for.

These are my own photos from events at Barkston Heath in the UK

I too spoke with Derek on Sunday, where his Swift was going well - pity about the trees - but neglected to ask him about his new EDF unit, which I saw demonstrated at Impington Indoor Meet in March.
 
I should have asked him whether it would be suitable for the old vintage Veron FD2 I wrote about in  
 
http://www.jetex.org/archive/smoky/200604.shtml
 
I get questions from colleagues in the Society of Antique Modelers about this one, and Peter Coombe has an actual (and Vintage) example that he wishes to convert to EDF with micro RC:
 

 
Peter says he is rather struggling with all the possible combinations of motors/batteries/controlllers, so any advice would be most welcome.
 
Does anyone have a contact no for Derek?
 
Like Russ I have seen his MiG 15 flying for a number of years, but not recently.  
 
I find that at the flying field I'm so focussed my mind for other things goes blank!
 
I am planning a long article about Phil Smith's Veron ducted fan models, so any advice about a modern power train that I can include in a final paragraph to encourage their restoration or replication would be very welcome.

Steve:
 
Thanks for the link. When Derek and I communicated and worked up my special controller it was too early to know these details.
 
65gms thrust on 2 250 cells is very encouraging and suggests reengineering the Aerographic Hunter for this unit will not only give it good thrust to weight but bring the ducting down closer to scale diameter. Doesn't state the discharge rate ("c" rating) however this cell size is very popular and a search may show it's available in new very high discharge configuration for the heli guys.  
 
Here in the states, duration with small scale EDF  is challenging because carrying an R/C sized battery doesn't work for FF. Unlike an electric prop of most any size, small EDF have very inefficient thrust development. The way around this is to test. There needs to be launch and climb out thrust for at least 30 seconds then acceptable thrust to maintain with the stabilized voltage remaining. The smallest pack to accomplish this with 6.4 volts still showing is what you need for FF. You can't simply set the timer for 120 seconds, launch, motor around then pick up your jet.    
 
One more tip for you new would be brushless motor EDF modelers, get ready for high torque reaction. Thrust development is inefficient therefore the motor has to develop very high power and it shows in a strong torque turn that can screw your model right into the ground.  
 
Guess I'll contact Derek and order up one, this old 150% Rapier Flitzer needs a retrofit. All my stuff is too small.