Ultra Stupid Funjet!!!

[akent]

Ok. Here goes!

I'm going to try to hit 150mph with a stock Funjet!

Here's what I will run:
1. Turnigy Typhoon 1800kv motor (37mm x 50mm hotrod Trex 500 motor)
2. Turnigy 100 amp ESC
3. 7x5 and 7x6 Pylon racer prop to begin with.
4. 5s 40-50C batteries (1800 and 2200ma)

I am waiting on the motor, props and batteries that are on order now!!! I also have another speedo on the way... I have the airframe here.

I decided not to run the 500L Align motor as it runs really hot in the air. Inside a fuselage it would probably melt the airframe.

I decided to try a more powerful combo than RC Foam Fighters used to hit almost 150mph. As far as I can tell, their Funjet is stock other than fiberglassing the inside of the fuselage by the motor. I don't know yet if that's necessary.

I know I said elsewhere that I wasn't ready to do this, but man, it's a sickness! But hey, it's sure FUN!!!!!! I find myself daydreaming about what it might be like to fly this thing!

It should be nuts!
Kent

[Gabe]

Dude, you're definitely a darksider!

[19000rpm]

Very sick man. ;D

[elkmaster01]

Update kent???

[akent]

Jul 28, 2010 16:27:59 GMT -6 @elkmaster01 said:

Update kent???

Howdy Elk! Good to hear from you!

Yes, I have all the parts except for a proper ESC here. The 100 amp one I ordered from HC will not fit in the airframe. I have another one that should fit on order, but it's rated at 90a with a 100a burst. We'll see how it holds up. I'm running a separate BEC now, anyway.

I removed the bottom plate on the Typhoon motor so it will be able to breath a little better. The fan part is built into the motor. With that plate on there, it did not pull much air through it when I ran it up.

Here is a picture of the airframe so far, with an 80a ESC. I am using that to fit everything and run the motor some.

I hope the ESC will be here next week.

I can't wait!
Kent

Attachments:

[akent]

One of the motors in this picture is the one going 110mph consistently in my current Funjet!
Oh, and a hint...It's not the bigger one!

Attachments:

[akent]

Over 2.1 Kilowatts with a 7x5 prop!
I'll be working on that, as I can't find a 150-200 amp ESC that will fit in the fuselage...

[19000rpm]

That's some crazy watts and amps. Sorry, can't help with a recommendation for a 100-130A ESC. That's about 4X's as big as I use.

Seriously though, isn't that set up going to put out a tremendous amount of heat...Like foam melting, fire starting heat?

[Gabe]

Time to turn to the Phoenix ESC's. I'm running the ICE 100A lite in the Stryker. With an 8x6 prop and 6S batteries, I'm only pulling 74amps and still pushing about 1950 watts.

The ICE 150amp is $270, but it has data logging. They're kick a$$ ESC's but they're on the pricey side.

You could try a lower KV motor with higher cells in the battery to lower the amps and save money on the ESC. Just a thought.

[akent]

19k, there is not a lot of heat. But it is there! The wires get warm.

Gabe, what kv is the motor you are running?

I am looking at those ESC's. They are certainly nice.
I am going to try some smaller props on 6s now, too, to see if I can get the current down.
I just need to get in a tapered reamer for the props. The prop shaft is 5/16".

All of this experimenting needs some other input. I think I'll build a thrust tester. I can build one with a dolly connected to a load cell. I already have a board that I designed that can read the load cell and send the data to a computer. That and a tach reading along with the Wattsup info will provide good data.

Kent

[19000rpm]

Testing sounds like the smart thing to do.

[Gabe]

Kent,

The custom Mega 16/40/1.5 combat was tested at 1332kv.

I can run a 4S battery and an 8x6 prop at 74amps. The 6S battery with the same prop puts me around 90amps if I remember correctly.

Remember, you have to pump more volts through a lower Kv motor to achieve the same RPM as the higher Kv motor. However, you will have more torque no matter what.

[Gabe]

Kent,

Please disregard the previous data. I bench tested it today and came up with 83amps with my 4S on the 8x6 prop and waaaaaay more on the 6S battery. I can only run a 7x8 prop per the initial motor test data on a 6S (from the darkside guys). I have to bench test with my current setup to confirm.

Sorry for the confusion.

[Gabe]

Just ordered mine today! Went with the MicroDan 2550 motor from gobrushless. ChippedProp from the darkside helped design the motor specifically for FunJets. Ordering HiTec HS 85MG servos and the Phoenix ICE75amp with data logging. Looks like I can use my 3S or my 4S Zippy 2200's for this. Just gotta change props.

It's supposed to make over 500 watts with thus setup at only 38amps.

[akent]

Aug 2, 2010 8:29:11 GMT -6 Gabe said:

Just ordered mine today! Went with the MicroDan 2550 motor from gobrushless. ChippedProp from the darkside helped design the motor specifically for FunJets. Ordering HiTec HS 85MG servos and the Phoenix ICE75amp with data logging. Looks like I can use my 3S or my 4S Zippy 2200's for this. Just gotta change props.

It's supposed to make over 500 watts with thus setup at only 38amps.

Nice! I think you will really like flying the Funjet! These things are a BLAST to fly! This is my favorite of anything to fly.
I just bought a third airframe!
I have my old faithful 110mph one, then my BEAST with the Typhoon motor that I hope to fly in the next few weeks, and a third one for a backup. I will always have at least one of these!

Is the MicroDan motor 2550kv? If so that is about perfect for 4s, if it can handle the power.
I can't wait until you fly it! These have massive room in side, compared to a Stryker and they launch so much easier.

These support 35mm motors with no mods, and have an adjustable motor mount for the attack angle!
Those Germans really did a bang up job designing these!
Kent