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Old May 27, 2007, 04:39 AM
Resistance is Futile
camship's Avatar
United States, FL, Panama City Beach
Joined Oct 2001
2,680 Posts
Krell Mothership

After many delays and more changes the Mothership is finally nearing it's need to be pushed off the building table. It of course will only make small hops until it learns to master it's new winged freedom.

I am still awaiting a shipment from VarioProp in Germany for my counter rotating prop blades. The current single motor setup is for primary testing only.

The final configuration will be twin direct drive 5.8" 3 blade speed props on the same Mega 16/15/4's running on 4S2P 4000 Polyquest lipo's. So basicly it is a giant speed wing.

So far 110 oz. less batts, motors and controllers, (EDIT: that actually INCLUDES batts, one motor and one controller) AUFW with the aluminum covering. BTW, only 5 1/2 oz. of that total weight is aluminum. The stuff is only 0.002" thick. About 10 times thinner than average aluminum foil. And has a tensile strength of 23in. lb. at that thickness. It is also a "dead-soft" aluminum so it will stretch too, (within limits).

Camship
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Last edited by camship; May 28, 2007 at 06:47 AM.
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Old May 27, 2007, 06:00 AM
Registered User
California
Joined Apr 2006
1,247 Posts
Quote:
Originally Posted by camship
So far 110 oz. less batts, motors and controllers and with the aluminum covering.

Camship
Aluminum covering?!?! Where do you plane to install your RX antenna? Doesn't a large conductive surface like aluminum covering could effect the range of the RX?

~asm
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Old May 27, 2007, 06:27 AM
Resistance is Futile
camship's Avatar
United States, FL, Panama City Beach
Joined Oct 2001
2,680 Posts
Quote:
Originally Posted by asm_
Aluminum covering?!?! Where do you plane to install your RX antenna? Doesn't a large conductive surface like aluminum covering could effect the range of the RX?

~asm
The RX antenna for the RC system is routed out of the airframe and into a protective plastic tube that stands about 1/2" off the surface and runs aft off the trailing edge of the wing into open airspace behind the AC.

Also proper placement of other TX/RX antennas relative to the aluminum skin makes a great backplane for higher frequency stuff.

Most modern AC are all metal too. Antenna placement is the key.

Camship
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Old May 27, 2007, 07:50 AM
Live FPV or Die
VRflyer's Avatar
Montreal,Canada
Joined Feb 2002
3,963 Posts
Aluminium covering will not let video signal pass through. I strongly suggested you make some test on ground with your video equipement.

On my first planes, I use monocote that look like miroir, it have metalic particules in it. I remember seen a huge difference. I remove it finally.
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Old May 27, 2007, 03:11 PM
Resistance is Futile
camship's Avatar
United States, FL, Panama City Beach
Joined Oct 2001
2,680 Posts
Quote:
Originally Posted by VRflyer
Aluminium covering will not let video signal pass through. I strongly suggested you make some test on ground with your video equipement.

On my first planes, I use monocote that look like miroir, it have metalic particules in it. I remember seen a huge difference. I remove it finally.
I am actually counting on it's blocking RF. I do recall you or someone else mentioning that about the metallized covering. It is not surprising. I have Metallized Mylar braided cable covers made from the same material, (Mylar or metallized poly-vinyl) that are mildly conductive I use for shielding on home-made cable assemblies.

Actually I am counting on the metal surface to minimize or eliminate completely any external RF influences on my system. All my antennas are external. So, hopefully no problem.

I am actually going to test placement of my data and video TX antennas by suspending the AC in the air and making measurements based on receiver RSSI being recorded by the Eagletree system. I will at the same time be running the recorder in the FMS FS8 to check for glitching while the 900MHz. and 2.4GHz. TX's are operating. All this before it even leaves the ground with anything other than normal RC gear.

I got too many expensive eggs in this basket to just toss it to fate and the winds

Have a good one.

Camship
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Old May 27, 2007, 03:33 PM
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AndrésMtnez's Avatar
Madrid, Spain
Joined Dec 2004
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Quote:
Originally Posted by camship
So far 110 oz. less batts, motors and controllers...
How are you going to do the launching? That´s a lot of weight, and with those hot motors with small props could be a problem. Do you have planned any bungee/catapult?


Andres
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Old May 27, 2007, 03:55 PM
Resistance is Futile
camship's Avatar
United States, FL, Panama City Beach
Joined Oct 2001
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Quote:
Originally Posted by AndrésMtnez
How are you going to do the launching? That´s a lot of weight, and with those hot motors with small props could be a problem. Do you have planned any bungee/catapult?


Andres
I do have a number of bungee options from a short 15' jetstart to a hi-start that has 250' of 25# bungee cord and a 900' cable. It's a long walk to set that one too! The bungee will stretch to 3x or 750'!

However I do not think they will be needed. Motocalc is quite generuous with 90oz. of thrust at 24,950 RPM with 3.5 pitch. That is just at the max RPM limit of the props I am using.

I have lots of other options but am trying to eleminate complexity so no gearboxes. I know I can go with the direct outrunners later.

Have a good one...

Camship


Camship
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Old May 31, 2007, 04:33 PM
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Swansea, South Wales, UK
Joined Jul 2003
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My contribution, My Magister with a 2820/12 axl motor 3300 11.1 lipo. Just starting out on the rocky fpv road.

Im using a 10mw tx with dsc[dual switching cameras] http://www.allendale-hosting.co.uk/rc-cam/DCS.htm. I only have one camera fitted but hope to have two, want to get used to the single cam setup first. I will be using the patch antenna from rc-cam as soon as the pcb sma plug arrives.

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Last edited by D_Deridex; May 31, 2007 at 04:41 PM. Reason: Left stuff out :-}
Old May 31, 2007, 04:36 PM
FPV Pilot
Crash9's Avatar
United States, MT, Missoula
Joined Mar 2006
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TREX 450XL FPV Helicopter

This is my latest FPV project I resently finished. I will post a build thread when I get a chance . I started with the 450 even though I have a TREX 600 still waiting to be built and the larger heli would be easier to fly but since I already have the 450 built along with a lot of spare parts I figured I would do my FPV heli training with it. I've been practicing with G3 Flight sim in the cockpit view for quite sometime and have done 3 FPV flights with the 450 around the yard hovering and I can't wait to get out in the open. I've been flying RC helis for a couple of years and this has been one of my goals.
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Old Jun 01, 2007, 04:40 AM
Live FPV or Die
VRflyer's Avatar
Montreal,Canada
Joined Feb 2002
3,963 Posts
Deridex: if you intend to put the 8dbi patch antenna of mr.rc-cam onboard the planes, it will not work well when the planes will be low, but is you install it on the receiver, it's perfect.

Crash9: You made your school, the best to learn FPV is to start from a simulator, especially with a chopper. Good luck! Also don't use foam to dampen vibration, mount the cam tight on the frame or on the servo.
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Old Jun 01, 2007, 12:09 PM
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Swansea, South Wales, UK
Joined Jul 2003
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Quote:
Originally Posted by VRflyer
Deridex: if you intend to put the 8dbi patch antenna of mr.rc-cam onboard the planes, it will not work well when the planes will be low, but is you install it on the receiver, it's perfect.
Thanks anyway but yea I figured that

Ive seen your videos on Youtube, amazing!!

The Racing Track one!!
How long have you been FPVing!
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Old Jun 01, 2007, 02:33 PM
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Madrid, Spain
Joined Dec 2004
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Quote:
Originally Posted by Crash9
This is my latest FPV project I resently finished. I will post a build thread when I get a chance . I started with the 450 even though I have a TREX 600 still waiting to be built and the larger heli would be easier to fly but since I already have the 450 built along with a lot of spare parts I figured I would do my FPV heli training with it. I've been practicing with G3 Flight sim in the cockpit view for quite sometime and have done 3 FPV flights with the 450 around the yard hovering and I can't wait to get out in the open. I've been flying RC helis for a couple of years and this has been one of my goals.



Oh my god, now I have no excuse to don´t give a try to my T-Rex with the camera! lol

Very nice, I´ve thought about it sometime but never did it, now I´m more motivated

What´s your AUW?
Have you modify anything to fly fpv, like blades?


Andrés
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Old Jun 01, 2007, 04:24 PM
FPV Pilot
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United States, MT, Missoula
Joined Mar 2006
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Quote:
Originally Posted by AndrésMtnez

What´s your AUW?
Have you modify anything to fly fpv, like blades?


Andrés
I have a RTF (wet) weight of 30oz (850grams). I swaped the blades to the 325 from the 315. I'm surprized that the TREX barely notices the added weight . vrflyers is right also you want the camera mounted tight. I also use the main battery for video power and was very happy with how clear the test video came out . My flight times are 7-8 minutes with the gear and are 10-12 minutes without.
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Old Jun 03, 2007, 10:19 AM
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AndrésMtnez's Avatar
Madrid, Spain
Joined Dec 2004
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Thanks

Mine is 700g without video and I fly around 10min too in idle2. Will try it in the future

Is there any posibility to see a video of your FPV T-rex?


Andres
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Old Jun 03, 2007, 02:19 PM
FPV Pilot
Crash9's Avatar
United States, MT, Missoula
Joined Mar 2006
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Hers'e the video I posted on www.FPVvideo.com of testing the gear. not much but some hovering. I went today to get it in the wide open only to have a servo fail on the CCPM . I'm now replacing it and will go again.

http://youtube.com/watch?v=Vsa978SmdgQ
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Last edited by Crash9; Jun 13, 2007 at 03:38 PM.
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