Skygate CARF, Viperjet
- RTF
Seller:snobird Details:
$9,600.00
| 6/6/2013
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Posts: 133
Score: 100 Joined: 3/11/2009 Last Login: 6/4/2013 From: East Yorkshire, UNITED KINGDOM Status: offline
Jeff was kind enough to let me have a flight with his T12 powered Viper last weekend, what a great airframe JL have come up with, Id managed to log a few flights on a few different airframes, with a friends Test Flight on a 1.9m Futura, my Dads Ultra Flash and my Classic Flash and I thought the Viper tracked and grooved as well as any of them and also much easier to land in the slightly turbulent breeze compared to our Ultra & Classic Flash. The T12 providing just about enough push for some biiigggg loops .....only problem being......Jeff's Aileron ATV being set to around 6% Up and 3% down .....come on mate....turn up that Roll Rate and Jeff......your more than welcome to have a go with the Flash anytime you want, feel free to ask and Il even turn down my Aileron Rate
Posts: 100
Score: 100 Joined: 7/30/2012 Last Login: 6/18/2013 From: BournmouthDorset, UNITED KINGDOM Status: offline
Having used the 2 x 950ml JL smoke tanks as fuel tanks along with a single 1350mm tank to achieve a lesser CG shift in flight meant I had to devise a new position for a smoke tank.
Not wanting to fit a tank at the front negating all the work done to achieve a stable CG throughout the flight I have used the only remaining space left right on the CG just above the intake duct.
The JL smoke pump that came with the two moulded tanks also included a length of 3mm fuel tube,3mm-3mm festo fitting and a stainless steal injector stick All this came as came as a "Viper smoke kit" and is very good value bought from Jeff at Zedjet for only £95!
First job was to clean up and reduced the flange at the front of the turbine hatch and the same with the rear of the hatch bay on the fuz, I then found a tank that would fit in the space created.
Then I made up a shelf/plate to mount the tank and pump on from 3mm lite ply and a fixing plate to the intersection of the duct to spread the weight and form a hard point to fix to for the "shelf"
The mount its self straddles the turbine and lets the tank sit right on the now std 35mm back GG, I have my CG a bit further back than that but its so close to it as to make no difference.
The pump speed is variable and works best from 4.8-6v. You can run it direct from the Rx but to run the pump from a separate power supply the lead will need to be altered.
The lead on the pump is separated onto 2 plugs, one with neg and pos the other just the signal, I simply plugged all these pins into just one of the plugs.
I then modefided a "Y" lead by clippeding the positive wire were its pluged into the Rx and cut the signal from one socket for power input, The pump then plugs into the remaining unaltered socket.
I shared the power used for my lights that in turn is from my ECU battery via a 5amp reg, the pump draws very little power but I would rather use the ECU pack than draw from the Rx.
The tank is attached to the mount as is the pump with a Velcro strap, the tank cant slip forward as the pump is in the way or move back as the turbine hatch tapers at the rear.
The tanks overflow is connected into the existing fuel vent with a "T" piece and I will cut then use a Festo connector if it all needs removing, as will the smoke feed line.
The smoke tank is filled through a "T" on the tanks feed to the pump, a tap on the smoke out tube is closed both wile filling and to stop the fluid draining when the pumps not in use.
The mount with pump and tank can all be removed easly by undoing the 2 screws at he front and 2 at the rear then unplugging to lead in less than a minuet or so when its not in use As its right on the CG it makes no differance to the Vipers trim wether its in or out of the airframe, not that it weighs that much anyway.
The JL pump and stainless injector works well, It burns the oil completely giving a good amount of smoke at all throtel settings, I have the pump mixed to the throttle giving a bit more fluid at high throttle.
I have now modified the injectors end since the last time out and will let you all know if there is any improvement over the std slotted end and if it gives more smoke for less fluid.
The tank ive used is 800ml and gives a littel over 2,1/2 minuets of continues smoke, a bigger tank could be fitted slightly more forward but still making only a small differnce to the CG
I would be nice to have a bespoke moulded tank for this position not unlike the shape of the main fuel tank in a Comp ARF Flash but just a bit smaller Such a tank would be right across the CG and have more capasaty, but its worth remembering that with snoke on were litraly burning money!
< Message edited by modelmancan -- 2/20/2013 5:07 PM >
Posts: 876
Score: 100 Joined: 12/4/2009 Last Login: 6/19/2013 From: none, USA Status: offline
I had my steering servo turned upside down so that way when the gear is depolyed the servo sticks out the bottom. Meant I could use a longer servo arm for the steering. However I decided to try it the stock way, and noticed the gear hits the the head of the bolt because it sticks out too far.
Can someone show me how their bolts look, the ones closest to the strut? The pics I was sent by GJC seem to omit what these looks like underneat next to the strut.
Posts: 876
Score: 100 Joined: 12/4/2009 Last Login: 6/19/2013 From: none, USA Status: offline
I got it figured out, I will decide which way I like better.
The retract still wants to rub on the rubber servo grommets I had shave them down a bit.
The main thing I didnt like about have it turned around is the amount the servo wire moves, however I amnot sure that will change much.
There isnt much to complain about on this jet but the front gear is definately something though. I do not like the way the servo moves with the gear, lots of stuff to get caught up on and not to mention make the gear heavier and harder to actuate for the air system.
Finally, that servo wire moving like that is not a good thing!
But I know it works fine just gotta complain about something!
Posts: 908
Score: 100 Joined: 2/17/2005 Last Login: 6/20/2013 From: Central Coast, AUSTRALIA Status: offline
Don't use the rubber grommets,I didn't and here is how you can run your servo lead. I've set up plenty of jets like this with no issues. This is as far as I could get my camera in
Posts: 908
Score: 100 Joined: 2/17/2005 Last Login: 6/20/2013 From: Central Coast, AUSTRALIA Status: offline
Run the servo lead through the former (sorry iPhone puts the photos upside down)
So in a nutshell, loose the rubber grommets on the steering servo if you are using them, zap in a cable tie holder to the bottom of the servo, run through the hole to the right and under the battery tray. This works and has been fine for me since I have been flying it.
Posts: 876
Score: 100 Joined: 12/4/2009 Last Login: 6/19/2013 From: none, USA Status: offline
Oh thing your tangs are bent up into the metal? Thats a lot of stress on them... You have the same servo there is a 2-3mm gap between the tanks and the mount...
Received my Viper this week and i have a couple of questions:
My elevator is really hard to move, even after a couple of move, no way a 150 oz servo will move it...
Then, both of my fuel cap were popped out, they have be shimmed with tape at factory, really poor idea, any idea with what replacing it?? They are loose fit in plastic....
And the last question, i tried to put my Rabbit in it...Really small engine compared to the space availlable in the bay, is it too small of an engine to fly this airplane, i have the 19lbs version...
Thanks for any input, Alex
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Jetcentral Superbee, Rabbit, Cheetah Wren 44 in my Bergen Magnum44
Posts: 876
Score: 100 Joined: 12/4/2009 Last Login: 6/19/2013 From: none, USA Status: offline
Strange on the elevator, but I would not use a 150 oz servo, use 300-400 oz. My elevator moved very easy... I assume you mean the fuel tanks, mine were too tight I had to dremel mine out. Even if you tighten them down with the tubes IN it is still too lose? Only way I know to fix it is to use bigger tubes through them. But if they are too loose there is no way.
Here we go again, I will just say the rabbit is a small turbine you will have to mod the turbine mounts to make it fit, a very common thing for the rabbit. Also, even for my k100 I had to make the modify the rails to make it fit. Do this WELL, if not you risk turbine breaking free, this mean a very quick fire. I do not know if 19lb of thrust will fly it, I havent flown mine yet. It does have a draggy airfoil, so I would not expect to have unlimited speed and vert.
Posts: 2011
Score: 123 Joined: 5/29/2003 Last Login: 6/20/2013 From: Moreno Valley,
CA, USA Status: offline
quote:
ORIGINAL: leopaul
Received my Viper this week and i have a couple of questions:
My elevator is really hard to move, even after a couple of move, no way a 150 oz servo will move it...
Then, both of my fuel cap were popped out, they have be shimmed with tape at factory, really poor idea, any idea with what replacing it?? They are loose fit in plastic....
And the last question, i tried to put my Rabbit in it...Really small engine compared to the space availlable in the bay, is it too small of an engine to fly this airplane, i have the 19lbs version...
Thanks for any input, Alex
I am flying one with 24 lbs of thrust. It can fly close to the speed of bandit or faster. I normally fly at 50-60% throttle. Even though it has more profit than the F16, but it's more laminar airfoil and does not bleed off speed in turns.
In our local airfield, we have people flying this Viper with
T-12, MVT-80, and M-100. They are all flying fine. The one with VT-80 flies great, but not a rocket. However it's fast. When I saw it flies, it was doing at about 160-180 in a small Hemet field that takes 3-4 seconds to turn constantly in a lap. I will talk to the VT-80 pilot and see what his settings are.
Scott is flying it with a M-100 and he can tell us how he flies.
My is T-12. Same as William (in China) viper's engine. It's a big engine and fly it like a rocket. The plane is too clean and I need to max out the flaps so I can slow it down. Anyway I think this Viper flies best with 80-100 size turbine. Rabbit will give it an extra kick but won't be too massive. Of course anyone wants a rocket, then a p120 will be over the top.
This is a quote from mike lin in post 406 in this forum
Posts: 54
Score: 100 Joined: 5/6/2002 Last Login: 6/17/2013 From: Navarre,
FL, USA Status: offline
Hey guys, I have a rabbit in my Viper, and it is a great turbine for the Viper, I like seeing my airplane and the go stick is around 1/2, and if I need more I have it, I also have a friend that has the same set up (RABBIT) again it is one of those things, if you want to go fast spend the $, I love the set up...yes I did have to make mounts to make it fit but I had to do the same on my Elan...........if anyone has a Rabbit and they don't like it, list it and I have a friend that will buy it.....again if speed is what your looking for spend the $$$$ and you can be the top dog at your field....so far the Viper with the Rabbit has turned out to be the only bird I'm flying, hands off 9 min flights with 1/3 tank of go juice after each flight in the tanks..
Posts: 94
Score: 100 Joined: 7/20/2011 Last Login: 6/16/2013 From: zhanjiang, CHINA Status: offline
Hi guys, What about your little viper jet?Are you still flight it? My viper jet had more than 150+ flights.Share my recent maintenance and flight video. This time install 3-axes gyro(include Futaba gya431*2+gya430*1);install light system, The light system made by JetLegend;replace the aging oil pipeline etc.
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All Forums >> RC Airplanes >> RC Jets >> RE: JET LEGEND VIPER BUILD THREAD 
RE: JET LEGEND VIPER BUILD THREAD - 
.....only problem being......Jeff's Aileron ATV being set to around 6% Up and 3% down 
and Jeff......your more than welcome to have a go with the Flash anytime you want, feel free to ask and Il even turn down my Aileron Rate 
