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Old Jan 20, 2013, 08:14 PM
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Originally Posted by Xenon_RU View Post
Awaiting for your results!
I like Mercury a lot!!! but the price is pissing me off, its about price of the plane itself and 5-6 times more than 12CS unit. would really keen to read your feedback - is it worth of every peny?)
The motor is a very very nice design, very well finished. Being all metal, hopefully we wont see the fan hub flexing and allow the blades to touch the shroud like on plastic EDFs.

I've ordered the ESC and servos - so when the ESC comes in (wednesday I think) I'll be able to see how the motor goes under power. Still dont have a set of 5kg scales though.. I need to get on ebay!

The jet is waiting at the post office for me, it's too big for them to deliver LOL. I'll have to go down there one morning this week - thankfully it's at the business centre which opens at 6am so I can actually get in.
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Old Jan 21, 2013, 03:12 PM
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All my wings and stabs being covered by bubbles...(( I guess it can be caused by Stockholm's humidity or so. A long ironing hours to come..
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Old Jan 21, 2013, 04:17 PM
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I think that is happening to everyone. btw Stockholm is dry this time of the year, is it not?
What did you mean by AUW/Thrust ratio Xenon?
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Old Jan 22, 2013, 12:53 AM
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Originally Posted by Downwind3Zero View Post
I think that is happening to everyone. btw Stockholm is dry this time of the year, is it not?
What did you mean by AUW/Thrust ratio Xenon?
Well, its always humid here)

I mean weight-to-thrust ratio.. Should be at least 1:1?, or how much is required to keep flying horizontally without high G turns?
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Old Jan 22, 2013, 07:39 AM
It's like an addiction!
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For horizontal flight alone you don't need 1:1, you need 1:1 if you want to climb unlimited.
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Old Jan 22, 2013, 12:25 PM
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For horizontal flight alone you don't need 1:1, you need 1:1 if you want to climb unlimited.
Thats exactly my point - so, given weight of 3,2 kg - how much of thrust do I need for stady flight without aerobatics?
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Old Jan 22, 2013, 12:36 PM
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2kg of thrust would be the lowest I would want to go, that is about .6to1 ratio. the airframe has something to say about this also higher drag airframes will need more thrust to fly
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Old Jan 22, 2013, 12:59 PM
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2kg of thrust would be the lowest I would want to go, that is about .6to1 ratio. the airframe has something to say about this also higher drag airframes will need more thrust to fly
Thanks for your input!
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Old Jan 23, 2013, 11:36 AM
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Received my 12CS today. Prior to balancing decided to check thrust "out of the box"..
Guys! 3,2 (!) kilos on 80% of thrust on 6S!! Did not follow amps and watts, and totally refuse to do it until I balance the fan - because this "shouting box" FREAKING SCARES ME!!!
Good news anyway - meaning that I will land close to 0.9 or even 1:1 ratio - better than expected ))
I was thinking - is there any way to attach the intake ring somehow inside? It gives additional 30-50% of static thust, or there is no need for that because whole physics changes in a flight?
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Old Jan 23, 2013, 11:44 AM
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your intake ducting in the model becomes your lip so if your model come with intake ducts then you dont use it, mainly the lip is for bench testing to simulate a proper duct. also in models without intake ducting or open ducts then you would use the lip to avoid the losses of having no intake ducting....make sense
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Old Jan 23, 2013, 12:53 PM
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I also read in some theory article that lip helps to root a twisted airflow inside edf unit, acting like a wing or helicopter blade, with only difference that it is static, while air is moving. In that case the vortex is properly formed giving exra efficiency
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Old Jan 23, 2013, 02:06 PM
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the lip just allows air to enter the edf unit in a smooth, non-turbulant manner. turbulent airflow causes losses
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Old Jan 24, 2013, 05:47 AM
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An EDF on the bench pulls through air in a giant mushroom shape area from the front of the fan. If you don't have the lip on the intake air ill "catch" on front edges which causes turbulance inside, and all all the incoming air smashes into it. It means it takes more energy to get the same volume of air into the fan. Now, on an a plane like the ViperJet which has ducts, this air is fed in via the ducts, so any turbulent are will general smooth itself out before it gets to the fan unit, and the ducting is covering the edges of the fan anyway.
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Old Jan 24, 2013, 07:26 AM
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Issus, have you decided where to place FPV transmitter and antenna? which frequesncy are you planning to go for?

I am considering the following:
- Put video transmitter in the nose right next to ventilation holes for cooling, and turn antenna 90 degrees downwards (it will be safely covered even for hard belly landing), apply some ferrite on video cable
- Install ESC as far as possible to the tail, with radiator mounted inside duct tube
- Put Receiver, OSD, sensors and GPS directly under cabin canopy

This should help to awoid noice from ESC in video signal. What are your thoughts?
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Old Jan 24, 2013, 09:10 AM
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Originally Posted by Xenon_RU View Post
Issus, have you decided where to place FPV transmitter and antenna? which frequesncy are you planning to go for?

I am considering the following:
- Put video transmitter in the nose right next to ventilation holes for cooling, and turn antenna 90 degrees downwards (it will be safely covered even for hard belly landing), apply some ferrite on video cable
- Install ESC as far as possible to the tail, with radiator mounted inside duct tube
- Put Receiver, OSD, sensors and GPS directly under cabin canopy

This should help to awoid noice from ESC in video signal. What are your thoughts?
I'm going to pick up the aircraft tomorrow, So i haven't got it yet.

I have the ultra detail (lol) scale cockpit to play with here. I'm probably going to convert the rear seat of that into an FPV system. I'll be using 5.8ghz with a Circular Wireless (accept no substitutes) SPW. I'm hoping I can fit it all under the canopy.

I'm leaning towards using the ArduPilot Mega 2.5 in this plane, so that will be mounted inside probably on a plywood plate somewhere... need to look at the aircraft first to see where it will go. I'll connect the MinimOSD I bought one ebay for $15 to the APM via the MPX connector which has power and servo signals on it going to the canopy.

I'm planning on putting the ESC with the heatsink sticking into the duct, as someone else did earlier in this thread (sorry, it was a few weeks ago when I read it - so I don't remember who to credit.)

My GPS will either be way in the nose, or way in the tail. Possibly inside a wing... we'll see where it will go nicely. I'm hoping I can get the DragonLink antenna kept inside the fuselage as well, I want as little drag outside the fuselage as possible.

I'm not too fussed about the ESC, but i'll be keeping the dragonlink receiver on the other side of the airframe to the ESC, and away from the APM but thats about it. I don't think with the amp draw of a jet i'll get very far away, so RF layout doesn't really bother me, it's pretty hard to make a DragonLink not work for less than 1.5km range.

I've never seen any noise in video from an ESC. Everything will be in the pod using shielded wires anyway, so runs should be short and unlikely to pickup any noise.
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