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HeliProz . ZoomsHobbies . HeliHobby

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Scale Model RC Helicopters > Vario Dauphin
 
 
heli_headcase
Key Veteran
Location: Hovering around Atlanta

I third that...

If you want the all-around nicest scale heli, especially one replicating a turbine model, go electric. You'll be glad you did!


HHC

So many heli's - too little time...
10-08-2008 08:40 PM
 
 
hoveroops
Senior Heliman
Location: Traralgon, Australia.

Hey Patty , listen to these guys , electric is the only way to fly . lol .
I'm not biased much .

So what is a good electric combo for this size heli guys ?
What is the requirements for motor wattage , headspeed vs gearing , battery capacity and I guess you just need a esc that meets the requirements .

I'm trying to talk Patty into going the electric route with the Ec 135 but more electric the better I say .

cheers

Jason.
10-14-2008 02:54 AM
 
 
patty48
Heliman
Location: Gippsland , Australia.

Hey Jase
After out chat last night looks like I’ll take the plunge and go electric on the Ec 135, I guess it’s the closest sound and performance to a turbine and no mess we’ll just see what our on friends here say eh.
Cheers Patty
10-14-2008 04:01 AM
 
 
heli_headcase
Key Veteran
Location: Hovering around Atlanta

Zzzzaaaappppp!

Pat,

We may have to Skype again. Converting the Extreme is pretty easy and by going with a 12S pack will give you the performance required. Let me know if you want to schedule a talking session.


HHC

So many heli's - too little time...
10-14-2008 04:20 AM
 
 
hoveroops
Senior Heliman
Location: Traralgon, Australia.

I've got a Scorpion 4035-560 kv motor here , it's rated to 4.2 Kw .
Is that any good for this application ?

Nice photo gallery HHC .
Lots of nice machine work pics .

Jason.
10-14-2008 07:37 AM
 
 
heli_headcase
Key Veteran
Location: Hovering around Atlanta

Hi hoveroops,

That Scorpion would do fine as long as the correct reduction ratio is calculated. A custom motor mounting plate needs to be machined and installed in the forward section of the Extreme frames and a belt selected that couples all the parts together. The desired head speed needs to be decided first, number of cells for the pack and the rest is easy. 12S can give a high number of watt/minutes (12S, 5000mAH for example) and the head speed, in the case of the Dauphin, is chosen to allow strong fenestron performance.

If Pat isn't shy of doing a little extra work here, maybe he should do some preliminary test flying with the nitro setup to see what is needed for good fenestron authority, record the flight RPM of the head and then use that number to complete the calculations.

Or, he can wait until I have hands-on experience with an almost identical heli setup close to me. May take a couple weeks before that can happen but valuable data will be gathered from the testing.

Thanks for the compliments on the gallery Now go watch my videos of my Bell 412 e-conversion and listen to the sound.... flying isn't anything to rave about as I was in a hurry and there was WAY too much collective range available.
http://runryder.com/helicopter/t462850p1/


HHC

So many heli's - too little time...
10-14-2008 07:52 AM
 
 
patty48
Heliman
Location: Gippsland , Australia.

Hey Guys
Ok you’ve talked me into it plus sound like a good idea when it comes to all the mess you get with a nitro set up. I’ll most probably get all the parts I need to change it to electric now and put it aside till I finish the Dauphin.
Steve I already have the electric motor mount for the Extreme mechanics’ it came with the EC135 when I purchased it.


Cheers Patty
10-14-2008 10:34 AM
 
 
hoveroops
Senior Heliman
Location: Traralgon, Australia.

Cool Pat very cool .
I have a motor and an esc in mind for it .
Just need to know what sort of battery requirements such a large e heli would need milli amp hour wise and sort out a gear ratio .

Anyway , sorry for sort of getting off topic of ya build thread but it's sort of related , lol .
Just getting as bit ahead of the current project , hehhehhe .
It's all good though .


Jason .
10-14-2008 10:45 AM
 
 
heli_headcase
Key Veteran
Location: Hovering around Atlanta

I already suggested...

Quote 
Just need to know what sort of battery requirements such a large e heli would need milli amp hour wise and sort out a gear ratio .

My power source recommendation was 12S (~44V), 5000mAH. Should give 6-7min safely but I'm giving a rough guess here.

The Scorpion motor mentioned has a kV of 560. Times .85 gives about 475 rpm/V. Times 44V = 20,944 motor rpm. Want to guess at a head speed? I like as slow as possible for best efficiency and realism but the fenestron has the last word here. So say the main rotor needs 1600 rpm to spin the fenny fast enough. Divide 20,944 by 1600 to give the total motor-to-main rotor gear ratio of 13.09 to 1.0

I don't know the reduction between the secondary shaft and main rotor but for example we'll say it's 5.0 to 1.0. So what's the ratio from the motor to the secondary shaft? 13.09 / 5 = 2.618.

What size pulley is needed on the motor shaft? Guessing that there's a 70T pulley on the secondary shaft, 70 / 2.618 gives 26.737 teeth for the motor pinion

I'm really guessing with these tooth numbers and ratios as present in the Extreme mechanics so start counting gear and pulley teeth and substitute them for my numbers. That's basically how it's done. But head speed needs to be settled on before ANYTHING can be carved in stone. Also look for an Extreme clutch assembly with the pulley tooth count close to what's needed if you want a scale, turbine-like startup sequence.

More later.

Good night all...


HHC

So many heli's - too little time...
10-14-2008 11:09 AM
 
 
heli_headcase
Key Veteran
Location: Hovering around Atlanta

Little "Oops"...

I'm sorry to have to make a small change in the calculation values from my previous post. I stated that the voltage to use in calculating the gearing, etc, should be around 44V for a 12S LiPo pack. That's assuming a nominal cell voltage of 3.7V per. I should have used 3.5V per cell or 42V as the number to plug into the start of the calculations.

At least I remembered and caught the error

Okay, back to your regularly scheduled programming...


HHC

So many heli's - too little time...
10-14-2008 06:18 PM
 
 
hoveroops
Senior Heliman
Location: Traralgon, Australia.

Cool . Only needing 5000mah pack is good .
We'll have to see what Pat has as far as E conversion gearing with his Ec135 . I know he has the mount but don't know what there is as far as gearing goes ?

What else come with the EC 135 Patty ? The Clutch set-up for a turbine spool up is the go for sure 110% .
I watched that video of spool up and Wow . Very nice .


Jason.
10-14-2008 09:38 PM
 
 
patty48
Heliman
Location: Gippsland , Australia.

Hey Jase
Yep the clutch came with EC135 so it’ll sound like Steve’s Bell 412 plus a huge box of other scale stuff.
I had to shut the box it cam in I didn’t wanted to be temped to start building it before the Dauphin is at least up and flying, it’d be great to prime them both at the same time though
Cheers patty
10-14-2008 11:39 PM
 
 
heli_headcase
Key Veteran
Location: Hovering around Atlanta

Now we're talking! I have a phone call to make and some data to gather. If any of the information collected in the call has value at this time, I'll share it with you.


HHC

So many heli's - too little time...
10-15-2008 12:30 AM
 
 
heli_headcase
Key Veteran
Location: Hovering around Atlanta

Update:

Made the call, asked some questions and got no new info other than the planned head speed for this 'other' Vario Dauphin is 1450. In one week I'll have hands-on experience with it and can tell more.

Oh, the motor currently installed is an Actro 32-4.

Later!


HHC

So many heli's - too little time...
10-15-2008 02:56 AM
 
 
patty48
Heliman
Location: Gippsland , Australia.

Hey Guys
The Dauphin build continues the modification to the pitch slider on the Fenestron tail is all done big thanks Darrens & Tris Heli for there help with the tail mod & Dale C for turning up the fiddley brass boss with an m6 x 0.5mm thread on the end you can hardly see it let alone turn it up on a lathe good job Dale!!
The back plate of the Vario tail gear box had to be changed to a carbon fibre plate / mount, the MA pitch slider arm I used a M3 counter sunk cap bolt from the inside out to hold the pitch arm on then, made a carbon plate to stop it from it moving sideways that wont go anywhere it works a treat Tris !!
The build is just about spool up time maybe a week or so !!
The gear box with no blades is of the EC135 I have still in kit form, just figured I’d make two up while I was at it
Cheers Patty






10-20-2008 05:05 AM
 
 
heli_headcase
Key Veteran
Location: Hovering around Atlanta

Nice!

The tail slider system looks very nice but completely unnecessary. FYI, I flew my friend's e-powered Dauphin yesterday and will again today, I think.

Head speed was 1200 and 1390RPM but 1200 worked best. Gear ratio from the main rotor to fennestron is 1-7.5 so with a 1200 RPM main rotor speed you get 9000 RPM back on the fenny. Tail authority was plentiful in calm conditions and OK with a light breeze too. At the 1390 speed the tail worked good too but current draw went up considerably as well as motor and pack temperatures.

I quick guess/calculated a current draw in hover of 34A and was measured at 34.9A I also guessed at a power/weight of 75W/LB with a weight estimation of 18lbs. Cranking the speed up to 1390 recorded over 66A peak but don't know if that was due to the governed ESC quickly accelerating the head or if it was drag from the fennestron. A correct data-logged flight will reveal the answer to this question.

Battery pack setup is 12S, 4900mAH and a 10min flight at the lower head speed isn't out of the question.

Video of the 1st test flight was shot and I may post it somewhere. It's boring and uneventful but shows how easy a test flight can be when all the major details are addressed before adding collective

Oh, CSM SL720 gyros stabilizing a 4-blade rotor system. Yup, many things that could cause one to scratch their head if something goes wrong...


HHC

So many heli's - too little time...
10-21-2008 02:50 PM
 
 
patty48
Heliman
Location: Gippsland , Australia.

Hey Guys
Well she hovers just a couple of bugs nothing that can’t be tuned up and sorted out,the OS 70 seems to be doing the job so far,but i'm not going to hold my breath !! I still have an enormous amount of work to do on it like cockpit detail winch & nav lights, my main aim was to get it going hovering & test fly, I need to get inspected by a VMAA heavy inspector before I fly it at out club field, as it is now it weights 7 Kg’s more weight to come!! But apart from that I’m pretty happy how it’s turned out so far.
Big thanks to Heli Headcase for helping me set up the CSM 720's on the helitronix mixer,just a bit more fine tuning and it'll be sweet

Cheers Patty




11-12-2008 12:36 PM
 
 
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