90mm VIPER JET from HOBBYKING - Page 200 - RC Groups
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Jan 24, 2013, 10:42 AM
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Ascended's Avatar
I wouldnt recommend an antenna hanging out the bottom of an aircraft that could crush it or in any way allow it to have an unplanned interface with the ground. SPW's have a rather large frontal area due to their design.. Take Issus' idea and see if you can put the antenna inside the fuselage some where.
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Jan 24, 2013, 11:57 AM
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I understand your point) the proposal came into my mind due to very high frequncy (5,8ghz). Its penetration abilities are slightly above normal light moreover, taking metallized paint into consideration, I would be extremely careful - if you loose videolink it is almost impossible to takeoff googles, find plane in the sky and land it, while it is traveling 100+ kmh. If you put antenna on top, than most of the time your transmitter is in the shadow of the fuselage. Are you sure that signal will not loose some strengh if antenna is inside?
Jan 24, 2013, 12:32 PM
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Quote:
Originally Posted by Issus
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.
The problem I faced with circular polarisation - yes, it gives perfect pictue without any snow or disturbences UNLESS you have straight visual contact between Tx and Rx. Once I flew behind some trees and was almost blinded! Checked several times - same result! Meaning that even tiny bush (or metallized paint of fuselage?) can significantly impact received signal - because claverleaves do not "see" reflected signals at all, that concerns me the most..
Jan 24, 2013, 08:31 PM
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Issus's Avatar
The paint in the fuselage will do almost nothing to the signal. Things like a battery will create a RF shadow, or solid CFRP sections.. but paint might only attenuate the signal the tiniest bit. Even a 50% attenuation would only drop 30% of the max range, which still gives me several kilometres to play with.

Cloverleaf antennas have no purpose. Their radiation pattern is horrible. Use a SPW from CircularWireless, don't accept any antenna that has been hand made. Reflected signals will never give you a full picture, they give a fraction of a second delay which just smears crap on the received signal
Jan 24, 2013, 09:58 PM
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Issus's Avatar
So I have the viperjet now - tail is damage at the top of the rudder but fixable. Packaging is a dismal failure, consisting of the parts in a plastic bag and tissue paper. No foam or bubblewrap in sight.

The canopy is well and truly big enough to fit a Gopro 3, however unfortunately its just not clear enough. The vacuuform was either done extremely fast or on a mould with tooling marks still on it. This leaves stress marks/distortions in the plastic.

I might grab some 0.2mm PET or 0.3mm PET from HKing and try my hand at making my own canopy. I haven't had much luck with photocopier transparencies (for old projectors) in the past, perhaps this film will do better.

Failing that, I guess I could cut a section out, as bad as this would be for drag
Jan 25, 2013, 01:13 AM
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Yeah, I guess all Viperjet v2 are being received with broken tail end - so was mine
I will either put camera on the nose in front of canopy, or will cut out first section - not sure what will bring less drag..
Are you going to use tracker mount for SPW?
Last edited by Xenon_RU; Jan 25, 2013 at 02:16 AM.
Jan 25, 2013, 04:31 AM
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Issus's Avatar
Tracker mount?
Jan 25, 2013, 09:26 AM
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Quote:
Originally Posted by Issus
Tracker mount?
Ground pan/tilt platform with antenna tracker - it is always directed to the plane. Something like that (see pic). I will not use it because it does not help clavers
Jan 25, 2013, 09:33 AM
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Issus's Avatar
I don't see how this fan unit is going to fit in the jet without some serious modifications. Anyone got some ideas?

I was in the studio taking some pictures of some other stuff today, so I took one of the viperjet and the motor issue
Jan 25, 2013, 09:34 AM
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Issus's Avatar
Quote:
Originally Posted by Xenon_RU
Ground pan/tilt platform with antenna tracker - it is always directed to the plane. Something like that (see pic). I will not use it because it does not help clavers
Ah, Antenna tracker. No, i typically won't bother. If i'm flying far away i'll fly in the beamwidth of my helical, if i'm flying all over the place i'll use a SPW on the RX.
Jan 25, 2013, 12:41 PM
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Cool pix! )
I am afraid you will have to make some surgery anyway - also this unit is heavier than stock one, need to reinforce mounting. Anyway, couple of days, some epoxy, some balsa.. Isnt our hobby about it?
Be careful with this unit - if you press it too hard, it will not came back to round shape, as plastic one!

Today was balancing EDF using -Sergey's- method (vibration via phone), everything was fine until I manage to drop fan on the floor and it went to pieces To start all over again tomorrow
Last edited by Xenon_RU; Jan 26, 2013 at 06:18 PM.
Jan 27, 2013, 07:35 PM
It's like an addiction!
Downwind3Zero's Avatar
Both wings done.
Jan 27, 2013, 07:47 PM
Keith Thomas
keithtsr's Avatar
Looking good. What retracts and struts did you use?
Jan 27, 2013, 07:56 PM
3DHOG
jcdfrd's Avatar
looks like eflight 15-25's with Tamstruts fitted to them, very nice setup......the perfect setup
Jan 27, 2013, 08:10 PM
It's like an addiction!
Downwind3Zero's Avatar
Hi Keith, they are TamJet struts and the eflight retracts - put the same on your Habu too!
jcdfrd - you got that exactly right Overkill but it wont let go in flight.
Chris


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