|Apr 14, 2014, 05:23 AM|
I am looking for advice, ideas or comments on this project
I have designed a MIG 15 and would like to put a std out-runner motor with a 6" (maximum) prop in its guts
Has anyone seen this done or have any advice, or suggestions on motor etc
I an thinking (to keep it reasonably scale looking) the wing span would have to be 1200 mm and the fuselage is about 7 inch outside diameter at the widest part
I was thinking
Motor: D2826-6 2200kv Outrunner Motor (or similar) http://www.hobbyking.com/hobbyking/s...dproduct=12919
ESC: TURNIGY Plush 40amp Speed Controller (or similar)
Prop: 6x4E or 5 x 5 propeller
Will these be powerful enough ??
I have designed a prototype and had the plans printed and, I will commence building soon, I am hoping for a slide on grass takeoff
Look forward to your comments and ideas
|Apr 14, 2014, 07:30 AM|
That Sparks fellow did something similar. He is the one that has all those great toon planes. I know he did an F86 saber. Not sure on the Mig
|Apr 14, 2014, 08:10 AM|
Wow Tony !
I was thinking about an F-86 a couple of yrs back.
I thought about doing a Square Sabre like in the pix but never quite
put it into action.
I like the idea of the Prop inside.
I use that motor on my smaller Slide On Ground series of Fighters.
F-15, F-22 and Mig29 zooom zoom !
I was going to try a ROLLED TUBE of MPF inside with an EDF.
My 1st attempt at rolling did not inspire confidence in the project. :-(
I'll be watching this one fer sure.
|Apr 14, 2014, 08:37 AM|
My 2 Cents
Have used this exact motor and ESC combo, plenty of power but needs big well to draw from, think 3S 2200 mah 25C, in order to maintain peak output....
Used it on WMPF Mako, with an AUW of 24 oz so thrust to weight should be ok..
In essence your thinking of creating a "whole fuse EDF" right?
Need some input from some guys with more prop science than I, but was thinking that you might want a "modded" prop, something that will take advantage of the ducted enviorment, maybe something like a 12 X 6 cut down to match as closely as possible the I.D. of the thrust chamber???
Ok so maybe more than 2 cents, but just some thoughts, like I said I have this exact motor and ESC if you would like some bench tests done just let me know, prob have most props from 6" to 12"...
|Apr 14, 2014, 09:02 AM|
WOW, thanks for the input guys
I too have used this motor, prop ESC combo in a lot of my models and I think is is more powerful than a 64 /70 EDF ... Slam, I am not really a fan (excuse the pun) of edf's
Mark, thats an interesting suggestion to use a cut down larger prop, wonder if the motor would handle it? ... Please if you have some time, do a few bench tests and let me know what you come up with
This is why I threw it open to you guys, I know there are a lot of clever guys out there ... a lot cleverer than me when it comes to the electrics side of things
I have little doubt that the Mig will fly, it all a mater of how much power it will need.
It looks like taking about one and a half sheets of Depron and about 1 sheet (Depron size 1000 x 700) of MPF (MPF is easier to roll)
I have the preliminary plans printed and ready to cut out the parts, I haven't gone to lots of trouble with the plans until I see what works and what doesn't
Look forward to any more ideas or comments
|Apr 14, 2014, 09:17 AM|
That motor won't handle 4s and if you plan to run 2 or 3s then the kv is not high enough for the size you are planning, realistically you are planning on building a 90mm or bigger EDF equivalent, I was going to surgest this one on 4s with a 6x4 speed prop http://www.hobbyking.com/hobbyking/s...er_2350kv.html but maybe the 3200kv of the same maybe better, but for me it does start to get harder to guess and remember the noise factor where you fly.
Just to add I am using the 2350kv above in a Sky Fun Jet on 3s which does get along at a nice pace and on 4s it will go over 160kph, but AUW is less than 1kg.
|Apr 14, 2014, 12:52 PM|
You definately got my attention now! Love the Mig-15...
A few things i learned with my slot-jet Mig..
That T-tail is BIG and heavy.. Flat wing did not work for me as expected in this case.. KFm2 improved matters a good deal. I used scale size horisontal stab which wasnt a good plan.. ended up enlarging a good deal after 1st few flights to make it work...
Mine was a profile, so maybe none of the above will be valid for yours
Cant wait to see your new plane go..
|Apr 14, 2014, 02:22 PM|
Let's be clear that using a prop inside the fuselage is not an alternative to EDF, it IS EDF, but with two blade fan. Generally EDFs use a multi-blade fan to absorb more power from the motor, given the restriction on diameter. (Remember that Italian full size DF with regular engine and two blade prop inside that flew about 1939. It had a huge tubular fuselage to allow the necessary volume of air to be moved at relatively low speed http://en.wikipedia.org/wiki/Stipa-Caproni )
Normal size EDFs need to move air through at higher speed and are inherently less efficient when it come to generating thrust at moderate air speed, typically requiring 50% or more power to fly a given model, especially when you consider the increase in weight due to the bigger motor and battery needed.
By the way, to maximize efficiency, it's important to have minimal clearance between the blade tips (which should be square) and the walls of the duct. This pretty much requires that there be a rigid metal, plywood or plastic ring with struts supporting the motor. In other words, you really need to think in terms of an EDF unit, whether purchased or home made.
To give a concrete example, the AquaCat is Polaris sized, uses the same motor as mentioned above and an 1800-2200 3s 20C battery. It flies for 6-8 minutes with lots of reserve. It weighs about 22 oz ready to fly and pulls about 20A for takeoff.
The AquaJet is essentially the same model with a Lander EDF unit instead of the motor and prop. It needs a 2800-3000 3s 30C battery and ready to fly weighs about 32-34oz. At takeoff it uses about 40A and throttled back it flies for about 4 minutes. What I like about it most is the sound, which always draws attention. What I like least are the short flights, but that's typical of EDF.
In short, it's entirely feasible to do a fairly light EDF MIG 15, but not with the same motor and prop as you'd use for an out-in-the-open setup. What you need is a regular EDF unit. The alternative, of course, is to stick the motor on the tail end with a normal prop pushing.
|Apr 14, 2014, 08:43 PM|
Joined Nov 2000
An... amazing to me, pattern of trying previously 'successful/proven' models with 'less'
Search.. IS our friend
Read this perhaps ?
|Apr 14, 2014, 11:14 PM|
Would you believe
Turnigy D2826/6 2200 Kv Brushless
Max I = 34A
Max Thrust (Theoretical) 960 g
Max Power = 342 Watts
As posted in various places on RCG....
Turnigy Plush 40A Esc
Venom 2100 mah 20C 3S Lipo
Watts Up Watt/Volt Meter
All props set for pusher config, thrust measured via electronic scale with tare set just before power up...
Base Line APC 6X4E
Initial volt 12.49 (Watts Up)
24.01 Amps Peak, 273 Watts, 26 oz / 735 gr thrust
Initial Volt 12.43
Greater than 32 Amps before "shutdown", test config failure, must have been a whole lot of power.... would have exceeded "safe" operation limits
Cox LH 5X3.5X3
(Change rotation on motor)
Initial Volt 12.34
24 Amps Peak, 260 Watts, 24 oz / 679 gr thrust
(Not as good as base line 6X4E)
But look what happens next....
Cox LH (5X3.5X3)X2
(Peak Charge Batt)
Initial Volt 12.43
Amps Peak 31.4, 344 Watts, 29 oz / 820 gr Thrust
|Apr 15, 2014, 01:05 AM|
Thanks for the comments guys and I have been right through the link you gave me on the cartoon Mig and Sabre … although I haven’t read every post in the thread, I have got a general idea of what he set out to do and what he accomplished … very well done Sparks, I can see you are a very talented guy.
Thank you Nigel, as usual my friend your comment have given me food for thought
Hey Shaun, thanks for the suggested motor mate, I will look at that too
|Apr 15, 2014, 02:14 AM|
A Regualar Propeller does not have those Stators.
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