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Old May 23, 2012, 03:55 PM
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SoCal
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I'm getting ready to maiden this Mig, I've been going over all the mixes to make sure that they are correct and double checking the rates and expos. My question is regarding the negative expos on FM3. Is -60 expo on elevator and -30 expo on rudder really needed? What are you guys running for expo on FM3?

Also, I only have 6 mixes on the DX8 so I did not do the KE mix, I don't see myself doing KE right away anyway.
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Old May 23, 2012, 04:07 PM
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On spektrum radios, isn't the expo +ve??
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Old May 23, 2012, 05:01 PM
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Originally Posted by jfetter View Post
Sorry for the delay guys, I've been running around getting the Migs built and my other planes ready and packed for E-jets, we're on the way now and I am posting from in front of BVM's factory where we're having a flat tire serviced.

First let me address the previous rip on this plane, it was harsh for certain. I understand where the guy is coming from though because this plane can be frustrating, let me try and explain.

First off, this plane is NOT for beginners or anyone that doesn't have patience and some radio programming ability and understanding of what they are programming. Let's start with that, 7 mixes, yes 7 but each does a very specific thing and all but one are required and even that one is recommended. Getting the vectoring to work with the rudders (full time) and elevators and ailerons (only in flight mode 1 and 2) requires 5 of the mixes. The sixth is for the gyro and seventh for opposite aileron-to-rudder/exhaust.

Next, the batttery! This plane doesn't draw 100 amps as someone previously suggested, it draws a whopping 119 amps on a 4400 mAh Thunder Power 65C!. Point is, always measure your WOT amps and calculate the shortest flight time, no excuse for anyone running out of juice with electric planes, you have to know your setup! Now, on to the servos. I found these to be exactly as Jason explained, they are quality, they are powerful and exactly what the plane needs. No jitter, no wandering center, they seem very well suited (name brand or not) to this application.

Flight! I understand why this guy was unhappy but you have to look at the mixes and understand what they do. If the plane is climbing and you use down trim, you are moving both the elevator AND the exhaust nozzles down, so this may work for power flight but not gliding (or vice-versa). The trick is to use the sub trim! We had the same issue, what appeared to be elevators and nozzles set to sero had the plane climbing on glide and diving on power. We simply used sub trim on elevator (down) and sub trim on vector 1 and vector 2 (nozzle elevation servos, up) until we got level flight on glide AND on power, with no wicked dive when throttling up. Of course this was done on the ground, not while flying!

The material seems perfectly fine except for the nose (you get 2, we quickly found out why) which is hollow and glues on. We dented one and broke another on landing, maybe these need to be plastic or foam with magents, not glue holding them on. Finally, power! This thing is awesome, it has power to spare! When used with Seba's pitch curve you can climb out on takeoff with authority at half power! On the 65C packs (which IMO you need to control heat, which is an issue @ 119 amps), this thing is a rocket and a real performer, hovering and pulling out of any issue with total authority. Does it need this much, 50 or 60 less Kv would make the amp draw likely well under 100 and performance would still be good but maybe no one flew it on 65C packs!

Mixes? You end up with 7 mixes and 3 flight modes. Mode 0 has normal control throws and vectored rudder only. Mode 1 adds full 3D throws and full 3-control vectoring and mode 2 adds the ability to select heading hold gyro by flipping the gear switch. we found taking off an landing in mode 1 a must for control (you really need the vectoring). I will add that you should be careful of the default negative expo on the ailerons and rudder in mode 2, they are ultra sensative and we ended up setting it back to linear as 60% negative expo is crazy!

Gyro? Cheap, yes and it does twitch on heading hold, we are not sure if this is a gain issue or just something it can't handle, we will play more in the next day and get video as well. I will say this, the planes are beautiful, the finish is great, the pin hinges and overall fit and finish is superb and while it has issues, it is a 3D twin, vectored thrust jet, wickedly manuverable and very powerful at the cost of flight time. You can get 4+ minutes if you fly it like a regular jet and do high alpha stuff sporadically on a 4400 mAh pack.

More to come later...

Jack
I found this post in the search. I think I too will start with linear expo for Aileron and Rudder in FM3 (actually FM2 on the DX8) and go from there. I agree with Jfetter, -60 expo seems like it would be crazy sensitive.

Thanks jfetter, good info on the Mig!
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Old May 23, 2012, 11:32 PM
Wats the worst that can happen
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Canada, BC, Surrey
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Quote:
Originally Posted by SMorrisRC View Post
On spektrum radios, isn't the expo +ve??
yes
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Old May 31, 2012, 02:33 PM
FLY IY, BREAK IT, FIX IT,
Hampshire, United Kingdom
Joined Jun 2005
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Hi all

I have just ordered the kit/servo/fan version (V1, but has had fans stripped and replacements provided) so need advice on motors/ESC's

I have had a search and see the 2W20's have been used, but were not as good as stock - are there any other good motors to put in the stock fans?

Can you get the stock motors in the UK?

I saw some early comments about crap servos, did this bare out as true?

thanks in advance.
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Old May 31, 2012, 04:46 PM
Wats the worst that can happen
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Canada, BC, Surrey
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Quote:
Originally Posted by Impailer View Post
Hi all

I have just ordered the kit/servo/fan version (V1, but has had fans stripped and replacements provided) so need advice on motors/ESC's

I have had a search and see the 2W20's have been used, but were not as good as stock - are there any other good motors to put in the stock fans?

Can you get the stock motors in the UK?

I saw some early comments about crap servos, did this bare out as true?

thanks in advance.
I think it was petervrc who tried this first. he experimented with the same (or similar) motor as you say. He resigned himself that the stock motors are better.

I tried the 2800kv turnigy motor from HK, which didnt work out so well. i think you can search for my previous posts. i bought 1 stock motor to compare (which I am finally going to get around to tonight to measure thrust & power demand).
Before finally throwing in the towel and going with stock, i have another 3300kv motor that looks promising. i wont know for a few weeks until i get the proper shaft adapter to fit the stock housing.

the quick answer is no...noone appears to have found a more suitable motor over the stock one....yet
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Old May 31, 2012, 05:04 PM
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Correct. I recently asked Hacker Motors who are also distributing the Seb Mig if they can recommend one of their own motors over the stock ones and their answer was a clear "no".
Best Stephan
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Old May 31, 2012, 06:30 PM
Wats the worst that can happen
TheCure's Avatar
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Originally Posted by schiwo1 View Post
Correct. I recently asked Hacker Motors who are also distributing the Seb Mig if they can recommend one of their own motors over the stock ones and their answer was a clear "no".
Best Stephan
Same here. Also asked Sebart too - same answer to use the stock motors.
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Old Jun 01, 2012, 01:46 AM
FLY IY, BREAK IT, FIX IT,
Hampshire, United Kingdom
Joined Jun 2005
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thanks gents - where can you get the stock motors from? I've looked, but am struggling.....
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Old Jun 01, 2012, 02:15 AM
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USA, MD, Frederick
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Have you tried contacting the manufacturer, Freewing? Another possible source is RC-Castle. They have a link to show Freewing parts: http://rc-castle.com/shop/index.php?manufacturers_id=50
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Old Jun 01, 2012, 03:27 AM
FLY IY, BREAK IT, FIX IT,
Hampshire, United Kingdom
Joined Jun 2005
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Originally Posted by fredmdbud View Post
Have you tried contacting the manufacturer, Freewing? Another possible source is RC-Castle. They have a link to show Freewing parts: http://rc-castle.com/shop/index.php?manufacturers_id=50
Thanks - I have emailed Freewing - has anyone actually confirmed they manufacture this plane?

Nowt on RC Castle, but will also email them.

Appreciate the pointers - how frustrating that there is so little information provided by Sebart!
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Old Jun 01, 2012, 03:56 PM
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Munich
Joined Dec 2008
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Quote:
Originally Posted by juice555 View Post
I think it was petervrc who tried this first. he experimented with the same (or similar) motor as you say. He resigned himself that the stock motors are better.
I think it was me !

And the difference between stock and 2W20 was big. Much much more headroom with the stock motors.

Cheers,
Henrik
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Old Jun 01, 2012, 10:02 PM
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Quote:
Originally Posted by Impailer View Post
Thanks - I have emailed Freewing - has anyone actually confirmed they manufacture this plane?

Nowt on RC Castle, but will also email them.

Appreciate the pointers - how frustrating that there is so little information provided by Sebart!
Pretty much. Check your vectored thrust nozzles, see if you can see the Freewing logo molded on the ball ...
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Old Jun 02, 2012, 05:01 PM
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Wiltshire England
Joined Aug 2010
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Guys.... Just picked 1 of these up and have a few questions.

1. Has anyone used a bigger battery for longer flight times?? I see its 3-4 mins

2. Are the manual settings [JR] any good?? I'm on Futaba

Thats it for now, cheers..
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Old Jun 02, 2012, 06:46 PM
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Wiltshire England
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Found something else whilst putting it together. Coming from the gyro I have a split lead joined to rudder and then gyro sense single white lead which then goes into servo extension plug marked as gyro sense! So far this all makes sense coming from helis.

However I also have a 2nd servo extension lead (loose) marked as gyro sense? I can't see what this is for as the existing one reaches the rx

Any ideas? Or just a spare put in by mistake?
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