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Old Dec 27, 2012, 04:54 PM
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United States, CA, Modesto
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Originally Posted by OldOz View Post
BThirsk -
Seems like a very useful piece of kit (if you have a spare R/C channel). Also pretty straightforward, but if I can help in any way, of course I will.
I'd say Hinnerk is the 'electronics expert' I certainly WAS one, once, back in the day: now just an old guy that remembers a few things (but a good hand with a soldering iron still!). Which brings me to:

Arrowshooter -
Realise my earlier post about the BL tail conversion was a bit involved, and too stuffed with technical acronyms. Bottom line (AFAIK) for you, and those interested generally is probably better put as -
1. The Xtreme brushed to BL cannot be used on a stock F45 RX tail output (this applies to the 'old' series of PCBs: haven't had a new one to test yet).
2. The simplest modification to make it work is (probably) to replace the tail motor driver FET with a larger unit. I have used the (now surplus) main motor driver FET successfully: and will test others later.
3. This mod should NOT be attempted by anyone without good soldering skills - there is a definite possibility that the Rx PCB could be damaged.
4. My mockup seems to be working OK, but the real test is in the air. However, TumppiT thought of this fix, and reported that it worked well. Finally,
5. I can't think of any (at least easier) other way to doing a BL tail conversion, using the standard F45 Rx PCB.

You surely have assembled a great collection of parts though - I'm really interested in seeing how they all come together .
I am chomping at the bit for the parts to arrive for sure. Right now I am working on the antirotation loop. I was ready to do some wire moving for the aileron servo until I fugured out I could just move the servos around. Looks funny with the elevation servo in the front. LOL

After I have this thing flying well, I am going to skip the brushless tail and go straight to the belt drive. Parts I will use are a walkera receiver for the UFly which has a brushless motor, tail rudder servo and Flybar. Will match with a walkera transmitter. All that will be left of the F45 will be the rotor head.
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Old Dec 27, 2012, 05:10 PM
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United States, CA, Modesto
Joined Aug 2012
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Quote:
Originally Posted by OldOz;23634582[B
Arrowshooter[/B] -
Realise my earlier post about the BL tail conversion was a bit involved, and too stuffed with technical acronyms. Bottom line (AFAIK) for you, and those interested generally is probably better put as -
1. The Xtreme brushed to BL cannot be used on a stock F45 RX tail output (this applies to the 'old' series of PCBs: haven't had a new one to test yet).
2. The simplest modification to make it work is (probably) to replace the tail motor driver FET with a larger unit. I have used the (now surplus) main motor driver FET successfully: and will test others later.
3. This mod should NOT be attempted by anyone without good soldering skills - there is a definite possibility that the Rx PCB could be damaged.
4. My mockup seems to be working OK, but the real test is in the air. However, TumppiT thought of this fix, and reported that it worked well. Finally,
5. I can't think of any (at least easier) other way to doing a BL tail conversion, using the standard F45 Rx PCB.

You surely have assembled a great collection of parts though - I'm really interested in seeing how they all come together .
Moki155 has the wires soldered direct to the board?
http://www.rcgroups.com/forums/showp...&postcount=894
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Old Dec 27, 2012, 05:12 PM
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Joined Dec 2012
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Well, it's been a calm but cold day here in Tn. Was up at first light so I could get at least one flight in before any wind might come up. As it turned out it's stayed pretty calm all day, don't think the wind reached more than 5 mph at any time. Got to fly three times with my one stock battery. Also received my double horse 9116 transmitter in the mail today to use with my v911. Just wish I didn't have to go back to work tomorrow. Have got to order two of those nano-tech batteries when I get paid again, then I can let the motors cool down while I fly my v911, and then fly again.
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Old Dec 27, 2012, 10:13 PM
John
Australia, QLD, Brisbane
Joined Aug 2012
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Well, sure as hell different in Qld from Tn. About 85deg, and humid. Plus gusting wind, annoying for test flights - so backyard only atm.
However, I now present the full brushless 450 mod.
It's certainly not the easiest MJX to fly (well, yet): but at least shows it can be done. Think I'm getting some RFI between the two ESCs: however, decoupling or toroids should cure that. Also, far from sure the 5 x 3 prop is ideal. But it works!
Some pics:
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Old Dec 27, 2012, 10:47 PM
John
Australia, QLD, Brisbane
Joined Aug 2012
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Quote:
Originally Posted by arrowshooter View Post
Moki155 has the wires soldered direct to the board?
http://www.rcgroups.com/forums/showp...&postcount=894
I tried that too: but - though you do have the heartbeat pulse there - the voltage is low, and polarity is inverted at the gate of the drive FET.
However, though I think your chosen route (a more suitable Tx/Rx) is going to be far easier, I kept going with the original Rx because of the potential usefulness of the mod to others, some weird kind of loyalty to MJX (it was my first 'real' heli): and probably sheer masochism lol.

The correct answer is a servo on a belt tail, imo. And a 6 chan TX. BThirsk's gadget (link above) could be useful on any spares.
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Old Dec 27, 2012, 11:28 PM
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Quote:
Originally Posted by OldOz View Post
Well, sure as hell different in Qld from Tn. About 85deg, and humid. Plus gusting wind, annoying for test flights - so backyard only atm.
However, I now present the full brushless 450 mod.
It's certainly not the easiest MJX to fly (well, yet): but at least shows it can be done. Think I'm getting some RFI between the two ESCs: however, decoupling or toroids should cure that. Also, far from sure the 5 x 3 prop is ideal. But it works!
Some pics:
Nice Pics! How do you have you PCB secured? Plastic stand-offs?

Definitely plan on keeping the stock tail for a bit before I pop for the Tx/Rx to use with the belt drive. Something tells me that flybarless won't be to far behind that though since all I will have to do then is swap the all-in-one receiver.
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Old Dec 28, 2012, 12:16 AM
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Canada, BC
Joined Apr 2012
1,501 Posts
This 450 conversion stuff is crazy interesting... unfortunately I'm still too new to this to understand a lot of what you guys are doing. I can't wait to see some good video of these franken45's flying to see how they compare to the stock and modded F45's.

Over the last few days I put together a short film with the F45 as guest star next to my Armattan Quad Copter. There's also a mini super cub and a wraith 4x4 in there. It's a long video as it's all worked around 3 full batteries (2 on the quad and one on the F45). I hope you enjoy it!

Flying Over Christmas (28 min 0 sec)
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Old Dec 28, 2012, 02:44 AM
Micro Heli mods
Tumppi T's Avatar
Finland, Tuusula
Joined Mar 2012
181 Posts
Quote:
Originally Posted by OldOz View Post
Well, finally have a working (mockup) BL tail: or servo tail.
I have to say is all credit to TumppiT: how on earth he found the problem - and solved it! without my electronics workshop resources is beyond me.
The basic problem is that the stock drive to the tail motor is a PWM signal, with a (very approx) 2kHz frequency.
The Xtreme converts this to a servo/esc compatible signal, again a more precise PWM, but at a strictly controlled PRF. However, this conversion relies on a 'heartbeat' signal from the original drive frequency (however short) to function.
With the standard FET, at much over half right rudder, this signal vanishes entirely: so the converter goes back to zero output. With an alternative (or higher power) FET this signal is preserved, so the converter maintains full right Yaw.
This is NOT a function of any power requirement, just a peculiarity of the drive signal/FET combination.
The pics below show the story. That showing the very short tail drive pulse is taken at full right rudder: and is totally absent when the original FET (actually MOSFET) is used.
Again, my thanks to TumppiT for leading the way!
Thanks OldOz,

I'm blushing here

As I told you guys before i found out the solution by a mistake. I fried the original FET...replaced it with the only FET that i had (from DH9104 PCB). When I was trying it .... I was at the moment luckiest guy in the world. It functioned really good and the cut-off problem was gone.

By the way...your F45/450 is so great that I'm planning to do same project as well
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Old Dec 28, 2012, 03:26 AM
Micro Heli mods
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Finland, Tuusula
Joined Mar 2012
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I know ...this is not a F45 thing....but have to show you.

I made a christmas present to my friend.

A helicopter landing plate:



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Old Dec 28, 2012, 03:29 AM
John
Australia, QLD, Brisbane
Joined Aug 2012
542 Posts
TumppiT -
However you solved the problem, you solved it - again, kudos .
Of course I'm biased. But I do think the 45/450 is superior in most ways to the 'standard' stock F45/EH200 mod. It's much more powerful, has greater wind authority, greater visibility, and will run up to 10min on a 2200 Turnigy: more if you go to 2650/3000 (and there's room and lift capacity).
However, it's NOT really an indoors heli anymore!
Good luck with your project. I followed pretty precisely MJX geometry: was a bit of a PITA to arrange an antirotation bracket and shaft adaptor, but the rest pretty straightforward.. Or you could follow Arrowshooters lead, who is really heading into more uncharted territory: but may well finish up with the 'ultimate' FP heli.
Or your own variant! - the very best of luck.


PS - TumppiT, that is one amazing landing plate!


Rexless -
Despite the foregoing, it'll be a cold day in hell before I've any AP to compete with yours! - got that crummy stock cam, plus I've still got a slight bobbing problem, which is next on my 'to do' list.
And your country scenery is so much more interesting than Brisbane suburbia!
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Old Dec 28, 2012, 04:10 AM
Brent 黑雁
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Canada, AB, Ponoka
Joined Jan 2012
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Quote:
Originally Posted by arrowshooter View Post
Nice Pics! How do you have you PCB secured? Plastic stand-offs?

Definitely plan on keeping the stock tail for a bit before I pop for the Tx/Rx to use with the belt drive. Something tells me that flybarless won't be to far behind that though since all I will have to do then is swap the all-in-one receiver.
I'm really interested in how flybarless would work with your combination.
I have 2 small helis for indoor flying as it is far too cold here to do anything outside as the gyros go crazy in the extreme cold weather.
One is a Walkera SuperFP ans the other is a MiniCP. They share most of the same parts except one is fixed pitch and the other is collective pitch.
I expected the FP to react similar or other FP flybar helis. Not so. It flys almost the same as the MiniCP. It does not self stabalize like a flybar Heli. Whatever orientation you set the Heli in with the AIL/ELV stick is where it stays similar to the CP. The only real difference is with the Fixed pitch, I have the dual rates set at 110% and the Collective pitch I have set at 70%. Now they fly almost the same. I need to move the CP up to about 85% and they will be almost clones in normal flight mode.
That's why I am curious on the difference in a larger Heli like what you guys are making.
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Old Dec 28, 2012, 06:01 AM
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Iím not a very active member here on RCG, but from time to time I will glance through the threads checking to see if thereís anything new or interesting. Admittingly Iíve only read a few post on the MJX-F45, so my knowledge of this helicopter is limit. When I was learning how to fly, the only cheap trainer helicopter out there at the time was the Esky Honey Bee FP. Like the F45 is now, the Bee in its day was a tinker/modders paradise. Sadly by the time the F45 came out I had already move past 300 size fixed pitch helicopters.

Anyway, to the point of my post. I for one think itís super cool that a few of you guys are turning your F45 in to 450 size beasts. Not all of us march to the same drum. I and a few others went down this road a while ago and had a lot of fun building a fixed pitch 450 size helicopter. Iím not much into FP helicopters these days, but wanted to post links to my two FP450 build threads in the hopes the builds might help out other Tinker/Modders.

Fixed Pitch 450
http://www.helifreak.com/showthread.php?t=262663
Flybarless Fixed Pitch 450
http://www.helifreak.com/showthread.php?t=332723
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Old Dec 28, 2012, 06:31 AM
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United States, VT, Windsor
Joined Apr 2012
354 Posts
This is the prop I use OldOz It's called a 5030 3 blade Gemfan got them from Hobbycool,com. I tried 2 blade and didn't like it. They are pretty inexpensive and if you look around they come in different colors. Your project looks good.

Ray
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Old Dec 28, 2012, 07:07 AM
Eugene
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Australia, VIC, Delacombe
Joined Oct 2006
918 Posts
Quote:
Originally Posted by Tumppi T View Post
I know ...this is not a F45 thing....but have to show you.

I made a christmas present to my friend.

A helicopter landing plate:
I want one Please!!
That is amazing and cool for night flying.
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Old Dec 28, 2012, 07:10 AM
Eugene
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Australia, VIC, Delacombe
Joined Oct 2006
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OldOz your conversion to the 450 parts looks fantastic I will be doing the same 10+
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