The Ghost

watt_the!, I am using 12cells 5000mah packs, at full power drawing 69.5amps and running at 3200watts. At half power using 25-30amps and getting 12lbs thrust.

Cheers

watt_the!

wow. 3.2kW for 17lb thrust.

is that in your F16?

does your rpm match up to the published byron data?

i.e. rpm v thrust?

can you tell me the kv of the motor you are using?

The Ghost

Got no idea of the RPM. The motor is the Hacker A50-12L-8pole Electric Turbine, and yes it is in my F-16, with all the options that have been sent my way there should be a lot of the old DF stuff back in the air, even though a lot of people want kero burners. The regulations in this country is why I got rid of mine(all the stuff required for a quick flight) and looked at something different. With electric, just throw a set of batteries at the model and fly, and no cleanup required, no tuning or the problems of engine runs that plaged them. With the improvement in motors and batteries, and the costs coming down it would be silly not to go this way.

Cheers

watt_the!

this is what i found on that motor....i admit ive never seen it before and it looks like an absolute beast.



Kv (rpm/V) 640
Max Power (W) 3000W
Max Amp (15sec) 90A
Max Efficiency 89%
Io (No load A) 2.5A
Rm (Resistance) 0.0245Ohm
Shaft Diameter 6mm
Gearbox N/A
Motor Diameter 55mm
Motor Length 79mm
Motor Weight 465g
Built in Fan Yes
Max Rpm 35,000
Poles 8
Case Smooth
ESC Timing 8-15deg
ESC Switching Freq. 8KHz

on 12s, no load should be around 27000 rpm with fresh packs and i'd guess 23-24k under load. (assuming 3.3v per cell at 70A)

i dont see why you were told that it wouldnt work as even though the power in is a little over its rating, the amperage is in the zone..maybe its running at 80% instead of 89%..

The thing with so called high quality motors is that they are very much under rated.. thats ensures their life and gives the impression they are superior...so it's probably good for 4kw even.

i cant find any thrust v rpm data for the byron fan...do you know where it is available?- it'd be nice to see what they show for thrust at the 23-24k level..it "should" be what you are getting.

I'm interested in what the AUW for the power system is...fan unit (?), motor, esc, cells...

and overall weight of the entire build.

then compare to turbine...i think itd be an interesting comparison.

BTW that F16 is beautiful- much nicer than bill hamilton's...

tim


**edit: i do see why you were told it wont work- its because a load of people think they know about DFs and really they dont. but they truly believe they do and will defend to the death even if it means getting abusive.
looks to me like that setup is pretty darn good.

The Ghost

Tim, I think it is more to do with the overall dia of the motor as it is larger than the center of the stator in the byron fan. With a few mods to the motor it fits quite well. Can't give a weight for the power unit but an AUW is around 11-12 Lbs, with retracts, which means that it should fly quite well. The motor is a monster amd works quite well, may be underated, but better than what others are using.

Cheers

watt_the!

wow. 11-12lb AUW...and 17lb thrust.

i see the diameter issue now. others are fitting extended shafts to their large diam motors to allow external mounting of the motor.

could you have mounted it in front perhaps?

i think if i search enough i can get a few datapoints to plot rpm v thrust..based on the IC reports...but i wont..lol..

mate how about total cost- power system only?

you'd have to get 500 cycles out of those packs as you're running them at 8c for most of the flights...i reckon you have it about spot on.

f16man

The byron fan seems to be still the most powerfull after all these years[must have had some good enginers with lots of DATA] we could never put up thrust like that in the 70's because no ic could turn those rpm's . Not bad for a 100 dollar fan unit with electric power, that f16 will have plenty of performance and I can't wait to see some video.........

The Ghost

Motor around $269 from Perth, Speed controller US$100, Batteries Zippy US$80 (X2) for 20C(both from Hong Kong), after approx 30 full run tests NO problems have been found with either speedcontroller or batteries. As I am not running the batteries at max rate the batteries don't even get warm, so they should last quite a while. I had fitted a longer shaft to the motor and then run a bearing in the stator housing but had a failour after a while (10 runs) so I sat down and had another look at the hole setup and came up with what I have now.

Cheers

watt_the!

so all up cost around $560US?

you got 12s 5000mah for $160US?!!!!...is that right?

that is amazing and is definitely taking the turbine market away.

i havent bought electrics for about 2 years- not been out much...i did notice prices coming down BUT....maybe im overusing the word "wow"..?

The Ghost

Check out [link=http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=6353&Product_Name=ZIPPY-H_5000mAh_6S1P_20-30C_Lipoly_Pack]Here[/link]. They have gone up (US$133) since last lot that I bought. The motor was in AUD bought from PerthRC, but you can see the cost to convert is only about what we used to pay for fan motors anyway.
Or if you don't need the high power then there are [link=http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7639&Product_Name=ZIPPY_5000mAh_6S1P_15C_]These[/link]
Cheers

watt_the!

well that is amazing...i heard alot of good things about the rhino packs too!

where do you find 12S 70A+ ESCs for $100US?

same place?

The Ghost

Same place under Speed Controllers. Just look [link=http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=4691&Product_Name=TURNIGY_Sentilon100A_HV_2-12S_Speed_Controller]Here[/link]
It's been a while since I ordered my batteries but have been ordering other stuff through them, mostly for prop planes, electric using only one of the 6cell batteries.
I ordered all my high dollar stuff back in Feb when the dollar was good, now that it's in the crapper look locally first for speed controllers as the conversion they cost more. You won't get the batteries any where near those prices in this country, cheapest I have seen 6cell 5000mAh batteries are AU$400, but you are looking at around AU$200 for the Zippy batteries. Half price, can't beat that.

Cheers

watt_the!

well it does make things very affordable now doesnt it?

i remember back in the day when 3s 2000mah 6c lipo were $130Au. a 25A ESC was $110Au and a motor was $90Au. ($330Au)

now i can get a similar setup for under $100Au!!!

edit: im going to start a fresh thread comparing turbines to electrics...starting with the wren.

can you join me?

The Ghost

No problem.

Cheers

Thomas B

My Feedback: (4)

Modern electric development has indeed brought mmany of the older EDF units back to life...just not the Kress ones...

watt_the!

oh and i can see that perhaps the form factor isnt quite there yet...the wren for instance still delivers a mighty punch at 75mm dia.

so yes i can see your point wrt retrofitting the older ICDFs and even the larger dia. turbines...and not just a replacement for any old turbine.

Tim

byrocat

I'm going to see if there's any real interest in bringing this thread back to life.

Two possible slants:
1) reworking old plans and kits to take compatible EDF units. (I've got a Verson FD-2 original kit built as wellas the plans)
2) re-engineering the old large fan units and kits to EDF.

The Ghost

May be a good idea. The batteries and speed controllers are getting cheaper, there are more motor manufactures that are starting to listen to the modlers and there are some more motors out there for large EDF.

Cheers

AllThumbs

Subarubrat....you ever get that Midwest He - 162 flying?

CoosBayLumber

My Feedback: (1)

The 162 by Kress Jets was near to same thing as by Midwest, as was taken off old Zirolli plans, then rescaled a bit. Was rescaled to fit newest DF unit by Kress.

Robert the original Kress was dead by this time.

Wm.

AllThumbs

I'm not familiar with a He-162 by Kress Jets...although I had heard the Ziroli He-162 plan set was redone with a smaller wingspan for electric DF.
Several guys have started building these old Midwest He - 162 kits for glo DF engines, but I haven't seen any flying reports...

Thomas B

My Feedback: (4)

The Kress He-162 is a much smaller model than the one kitted by Midwest. As I recall, Nick Ziroli also designed the small one and Kress kitted it for either the RK-049 or the RK-09.

RickP

My Feedback: (2)

Hello All,
Sorry to kind of hijack this thread, but it appears to have been idle for a while. I've just started a similar thread:

http://www.rcuniverse.com/forum/m_10872728/tm.htm

And there appears to be a lot of expertise here in an obsolete topic. I would be most appreciative if you guys could take a look and add a comment if appropriate,
Kind regards,
Rick

byrocat

Not realy hi-jacking but a valid quesiton, considering you're working with one of Dick Sarpolus's old designs. BTW, Dick designed the Axiflo and RK series of ducted fans. You might want to call them "generation 1", with the Dynamax being "generation 2", and the current generation being the incorporation of brushless motors and lipo batteries of high-capacity and C-rating, plus lighter building techniques.

The older/vintage designs can be reworked to make use of modern systems and techniques. However, I agree with the other posters in your thread the problems in the fan units to fully utilize the power of the IC Engines and the limited power of the older engine desings (COX and the ilk) will tend to limit what you can obtain.

The thirty years since the original designs has seen significant changes in the background engineering. Doing vintage stuff is a greatg exercise but if you're expecting modern levels of performance, yhou'll be disappointed.

One of my curent mini-projects is doing a MIG-25 based on the KOTA design but will utilize foam construction and modern ducting plus using an EDF systems.

RickP

My Feedback: (2)

Hello,
No, this is a nostalgia trip all the way. I could have easily purchased a modern EDF for what I have already spent just fooling with this project. I will be happy as long as it flies reasonably. I just don't want to be fighting to just keep it in the air. From the looks of it I'll build my own version of the RK-709 and if I can get any type of thrust out of it I'll be happy to proceed.
Rick