Funjet Fun !!!

[WingTips24]

Ordered my FJ today or at least put in my order, we will see when it gets here. Now for the oh so fun task of thinking how to outfit this baby. Makes for hours of FunJet thought.

Tips

[DetroitHawk]

I think i am going to with;

Himax 2825-2700
ThunderPower 11.1v 2100mah
and swing a 6 x 5.5 prop

seems like a good set up to start with.

[Schlepp]

Hawk, setup sounds hard on the battery. The prop size was wrong on your previous post on the Himaxx motor, try calculating with the 6x5.5 prop.
Should be a speedy setup if the battery is up to it.

[Moonwalker]

I have been told that "a good motor, like a Mega, will use roughly 150 mAH less juice and have the same output. Himaxx will take that extra juice and due to low efficiency, it will turn it into heat and try to self distruct over time."

Really, I can't speak for Himax since I have never owned one but I would invite anybody familiar with both to speak to whether the Megas are superior from an efficiency and "taking abuse" point of view.

[DetroitHawk]

I am sorry i put the wrong prop size. i intend on using a 5x5.5 not a 6x5.5.

Do you really think that the mega is that much better of a choice? I haven't bought the motor yet but that is what i was looking at getting. Look at these numbers and tell me if they sit any better with the different prop.



I didn't see a mega motor with a 2650kv. Which one were u looking at?

BTW moonwalker i made u a custom avitar:



lol

[Schlepp]

Looks like a good choice.

[Moonwalker]

Thanks for the Avitar!

The Mega is the speed 480 size motor which is a little heavier than the speed 400 sizes (16/15/x). It is MEGA 16/25/2 (2650KV). Been told this thing can take a royal beating and put out almost 1600 watts. It cost 10 bucks more than the speed 400 size.

[DetroitHawk]

Ok from what i can find out that mega 16/25/2 is about 1.3 oz heavier. But my calculator doesn't have that motor in there for me to run any numbers.


np on the avitar i made it for fun, i'll make one for anyone else who wants one, just ask.

[coz]

DH, What program is that?

[Moonwalker]

I found the following info on the motor. http://www.megamotorusa.com/Brushles...5-2.htm?id=406

Based on this info the following rough guess can be made:

3S with 5X5 prop will hit 116mph and draw 30 amps
4S with 4.7X4.2 will hit 139.2mph and draw 35 amps

[Crash Test Dummy]

DH,

I own 5 Himax motors and have been very happy with them, However I purchased a Mega 16-25-3 1700 KV and it is a rocket!!! It pushed my 30+ oz. V- Diamond to 97 MPH in level flight with a 6X5.5 prop on a Hyperion 2100 Mah 4S pack. It preforms very well also on 3S [sorry, I didn't get any radar data on the 3S set up but its fast] with a 7X5 and the thrust is awsome, unlimited verticle. That might be the sweet motor in the Fun Jet for those who want WARP speed. Just think how much faster the FJ will be compaired to a 30 oz. V-Diamond [with LG hanging down in the air streem] with that Mega, Hummmmm. Who cares if you need to add a little weight to the nose to hit the CG!!! I'm told you can run that Mega at 600 watts and more just by adding a simple heat sink, which I have added to mine. No hot motor upon landing and a cooler motor is a happy motor. I'm going to try my 2815-3000 Himax [with heat sink] in mine 1st but I know I'll end up with the Mega in there. I don't want to rob the V-D of its motor, but I might have to...........

CTD

[DetroitHawk]

Originally Posted by coz

DH, What program is that?

no program just a free link;

http://brantuas.com/ezcalc/dma1.asp


CTD:

Do you think that the 3 turn is a better choice then the 4 turn? (16/15/3 or 16/15/4)

What do you think of the 16/25/2 that moonwalker was talking about?

[Phoenex]

DetroitHawk

I see in your calculations that you are using a very high pitch prop which provides very little in-flight thrust. One of the problems you are going to run into is that at higher speeds the resistance to go faster increases. You may need to use a prop with at least a 1 size larger diameter than pitch in order to overcome that resistance and give you more vertical. Finding a setup to give you 100mph pitch speed this way uses a lot more power as you will see, but it may be required to get to that point.

[Moonwalker]

Hawk:

This one looks good too - seems VERY efficient but also costs $$$$$

Ran the numbers on 400-23 with 5X5.5 and it looks good over 100 mph pitch speed with low amp draw. (2300kv)
400-28 (2800kv) will give you another 14 mph at the expense of another 10 amps. Both weigh same as others you are considering. I may go for this motor for the Funjet as it seems I can just use my CC 25 and now have to go bigger on the ESC for 3 cells.

[DetroitHawk]

This is a motor that i have that isn't in use. What do you think of these numbers?

Also does anyone know what the funjet weighs without the motor and battery?

[DetroitHawk]

7x9 prop i found on the tower hobby site is interesting too. The amps are low for the high output.

http://www2.towerhobbies.com/cgi-bin...?&I=LX1512&P=7

[Moonwalker]

Hawk:

Using what you have on hand as a start seems like a good idea. I have decided to go with the Mega long can 480 size motor. It is about the same weight as the Himax but can take much more abuse from what I have read so far.

From a raw efficiency perspective, keeping it light with 3S is probably the way to go but I want to set one up with crazy power just for the challenge of stuffing as much stuff into it that I can and seeing if I can fly it well.

[Crash Test Dummy]

Originally Posted by DetroitHawk

no program just a free link;

http://brantuas.com/ezcalc/dma1.asp


CTD:

Do you think that the 3 turn is a better choice then the 4 turn? (16/15/3 or 16/15/4)

What do you think of the 16/25/2 that moonwalker was talking about?

I'm not sure which motor would be the best. I'll have to see the airframe in the flesh. I would lean towards the 16-15-3 or the 16-15-4 I havn't seen too many people running that 2 wind Mega. The 16-15-4 would be a natural cause you can run larger props for more thrust on both 3S and 4S packs. 6X5.5 is great on 3S, tons of thrust and good speed.

CTD

[Schlepp]

CTD is right, if I had to pick just one it would be the 4wind. 3s is light and still capable of unlimited vertical and 4s is quite a bit faster. 6x4 or 6x5.5 prop and a 1800-2600mah battery allows quite alot of flexibility.
I would like to try the long can 480 style mega though just for fun.
HET has the 2w-20 700 watt motor, might make a nice choice too.

[Moonwalker]

Hawk:

I would guess it depends what you want to accomplish with this bird. My little 13 ounce Microjet was dopplered at 134km per hour (83mph) this week on that little Parkzone 1880kv motor with a 4.75X4.75 APC(e). It has a little 3 ounce 1320mah and is really a fun little thing to run around the local park with, go straight up in a crazy barrel roll and just cruise around. If that is the goal, then those Mega 400 sizes would be fine as I find my 16/15/4 comparable with the 1880kv motor (a little quicker).

BUT, if you want to run that Funjet to crazy screaming mental case speeds of 120mph plus, then I have been told to stay away from 400 size brushless motors, because, as the amps go higher and higher they become more and more inefficient and therefore waste more and more energy into heat. They are more suited for max aerobatics and low stall speeds, but they save you only a few dollars.

For reference, there is a group of guys over on RC universe that are using long can Megas with 800-1200 watts to push Strykers up to 120mph. http://www.rcuniverse.com/forum/m_37...tm.htm#5015873 My goal will be to use a similar power system to see how far it will push the Funjet. The two set-ups of choice appear to be:

Mega 16/25/3 (1700kv) with 5 or 6 cells
or
Mega 16/25/2 (2650kv) with 3 or 4 cells

For a video of the former with 5 cells check out Dialed Chuck's video of his Ritewing Demon at a whopping 50 ounces at post 422: http://www.wattflyer.com/forums/show...t=8302&page=17

[termite]

Got the shipping confirmation from my distributor today; FunJets are on the way

I'm gonna go with the Mega 16/25/3 on 4S with a Graupner 6.5x6.5 speed prop. 37 amps and around 500 watts

I think you guys will find that the 16/25/2 on 4S will have a lot higher amp draw than your calc. program is comming up with (hope I'm wrong but would like to see the results.

I'll knock a couple bucks off on a 16/25/2 to the first guy who wants to try one! (send me a PM)

Randy
Dynamo Electrics

[Moonwalker]

I bought the Mega 15/25/3 as well. I plan on testing all types of prop combos on it on 4S, 5S and 6S with my new meter and will report back the results here when it comes in.

Randy, what is your best guess as to terminal MPH straight and level on the Funjet with that motor, the 6.5X6.5 speed prop and 4S?

[termite]

I haven't had one in my hands yet so hard to tell!

I had the same set up on a Twin Jet and it did 137 flat out.
What was cool about it was the climb rate, didn't seem to slow down much even while going straight up

Randy

[Crash Test Dummy]

Originally Posted by termite

I haven't had one in my hands yet so hard to tell!

I had the same set up on a Twin Jet and it did 137 flat out.
What was cool about it was the climb rate, didn't seem to slow down much even while going straight up

Randy

Didn't you run 7X7 props on that Twin Jet?

CTD

[Joe 1320]

All this talk of the Funjet make sme want one. Thanks guys.



I'll have to build it light, 3s lipo and brushless power.