MF480 16/15/2 Exhaust Size???

amy

Been searching around to find out what kind of reductions you guys are using while running the 16/15/2 in a MF480. But the only think I could find was on the speed 480. MY application will NOT be inside a fuselage. And I plan to use the stock intake lip. Basically in a stand alone design.
What kind of gains are there from running with a smaller exhaust diameter? And does it increase amps at all?
Motocalc is reporting that I will be hitting close to 50 amps static with a 3S lipo.
Thanks for the help.

Alright, second question. I was just playing around with the intake and exhaust dia in Motocalc. And I put in exactly what is off the fan. And the thrust figures went up 10oz. Now it reads 48.2 amps/47.8 oz of thrust static.
Do these figures sound realistic? Too high, low?
If they are actually higher than what I orginally calculated, then I can get away with running a 2S lipo. That would make thing much much easier.

Motocalc leaves a little to be desired for dealing with EDF's. While amps will rise a little there are great benefits to using a reduced outlet, among them are some acceleration of efflux. While using a constant diameter tube will cause a loss of thrust, I have seen outlets as low as 50mm being used but I think that is a bit tight, try 60mm as that IIRC is the diameter is 4.5in2 and the FSA is also 4.5in2 and from my tests with the little GWS fans it is not much more load as with no outlet at all.
Eric B.

Alright, second question. The model I am designing will be use static or close to part of the time, the other part it will be inflight. And motocalc is computing a flight speed of 143mph on 3S and  98mph on 2S. Which is totally fine with me.
The question is that since I am using it partly for static, would a straight through duct be better because of the higher static thrust? I am not really worried about what the eflux will be.
How close is motocalc to real world Amperage and thrust figures? Some of the measurements I am trying to get out of it are very important to final design.

Ok the 16/15/2 will give you a top end speed of near 100 on 3s, the 2s will be sadly disapointing. 3s will cause a draw of 45-46 amps.
Eric B.

This will be on a triple ducted fan unit with a projected all up weight around 40 to 45 oz's.

Good luck as the batteries needed for the 3 16/15/2 will weigh out at least 30oz.
Eric B.

give it a go anyway.
As for moto calc when it comes to DF its NOT accurate. that is my experiance any way. somtimes up to 18 amps off. THAT far to much.


Originally Posted by AirX
Good luck as the batteries needed for the 3 16/15/2 will weigh out at least 30oz.
Eric B.
What cells are you using for that calculation.
I am figuring at 15.4oz for 3 packs.
Also, I didn't double check my notes. But the all up weight is being project at 52 oz.

I used Irate 2200 at 3s 2p, 10.8oz per pack. The other direction will be a single pack of 3s 6p at 32.62oz to make the total watt requirements for 3 16/15/2 and required minifans.
Did you figure all the needs of the electrical side and figure the weight of the total system. You will be surprised at what you will need.
Eric B.

You mean like this.
Yes I have been doing my homework on this project for well over 6 months. As well as working on some custom electronics I will need for control purposes.

nem3
I hope you don't mind my input. You will probably need more battery to handle the 45 Amps your motor will pull.  If your 2P lipo is a 10C discharge battery that only gives you 42Amps.  Close I know but I have cooked lipos by pushing the discharge rate.
Definitely stick with 3S unless the quot;staticquot; meant Static Display   Let us know what plane you are outfitting.  Mabey a picture or two.
Your budget looks good.  (Couldn't help but notice that your Body cost is $0.00; I'll take two!
LOL,
Devoree

I think ive spotted your quot;deliberatequot; mistake.
The TP 3s2p 2100ma pack, is actually only 1p at 2100ma. The 1p pack will weigh 145g and cost you $75. Its rated at 10c discharge and will give you 21A.
What you need and i assume this is where the error has crept in, is the TP 3s2p pack which will be 4200ma and cost $150 each and weigh 282g
Youll see the pack as the second one down on the link below
products.asp?cat=10


Originally Posted by d bang
nem3
I hope you don't mind my input. You will probably need more battery to handle the 45 Amps your motor will pull.  If your 2P lipo is a 10C discharge battery that only gives you 42Amps.  Close I know but I have cooked lipos by pushing the discharge rate.
LOL,
Devoree

The gen 2 Thunder Powers, especially the new ones, will handle this with ease. Many folks are running these in the new Sniper jets and others w/ the 16/15/2 with great results. A friend has the combo, and even with no airflow over the batteries they are lukewarm after flight.
Bill Davenport
AMA 28141

What? the 2100ma rated at 10c has been ran in a sniper with a 16/15/2, running at 20c!! can you confirm which pack it is you mean?
And how long it lasted for?