RIGDESIGNER

Hi Jon, i'm just finishing my build and your sketch is exactly how mine went together and i also had a spare port which i just put a short loop line on

gsmarino2000

My Feedback: (2)

Javier,

There is something major wrong, either with your setup or your turbine. I would strongly suggest setting up the turbine and fuel system on a test bench and getting it right there before putting it back in the plane. Are you talking with Kingtech? I haven't seen anything on the support forum.

Greg

Jgwright

Greg/Javier

Unlikely there is anything major wrong with the engine, more likely that you are trying to start the engine with a 2 cell Lipo. You should use a 3 cell A123 Life battery 2300 mAh for best results with kero start. I agree set it up on a test bench and make sure it starts reliably and you are used to handling it before trying in a plane.

John

essyou35

My Feedback: (11)

Did you buy the turbine new? If not it may of been setup for diesel. Reset the ECU by setting the stock all the stock parameters in the ECU. don't skip one.

javier161

Thank you all, I bought turbine new, Yesterday I started it in a stand and same problem,never reached idle and long yellow flames. then I changed ecu from a good running k100 and same problem, then I went into the menu and tested both valves, and then it worked very well, short starts and running good.

Is there a way that by mistake I left a valve open or closed a few days ago when I tested the valves at home before the incident?

Jgwright

Javier

I recently was asked to look at a new K100 that was having problems starting, the engine would start sometimes and not others. I found after a lot of checking that the kero fuel valve lead was not making proper contact with the ecu pins. What was happening was the female connector was not locked in place with the little plastic tab. As the lead was pushed in the connector was pushed back into the plastic holder and only made intermittent contact. If one wanted to be critical the Kingtech leads are a bit stiff making it more difficult to make small plugs like these make proper contact. Hope you can understand this and check yours. After I made sure the plastic tab properly secured the connector the engine started fine. It could just be that you did not have the lead fully inserted into the pins.

John

javier161

Thank you John I will check that too.

Jon Mead

I've drawn up the ViperJet graphic, with the intention of getting some vinyl cuts done for the wings of my Viper. If anyone is interested, I'd be more than happy to send anyone a copy of the file as an .eps or other format by e-mail. Please PM me with your e-mail address, and I'll send it to you. Below is the jpeg.

Jim Cattanach

Flew the maiden flight of my Viper this morning. All went very smoothly. Fly's as if on rails.

Jgwright

Jim

Well done, seems like you enjoyed the Viperjet like everyone that has them. Did you go with the Vt80? If so you must have a very long flight time with stock tanks! You should loan us some of your weather, great day for a maiden.

John

Jim Cattanach

Thanks John. Yes, I went with the VT80. I think it is perfect for this model. I did not completely fill the tanks. I set the timer for six minutes for the three flights I had & the fuel level dropped by just over an inch, with mixed flying. I think I could easily get over twelve minutes using more power.
I really like this jet. It is very relaxing to fly & no vices, as far as I can see.
It was a beautiful day, virtually no wind. A little chilly at 20c (hence the sweat shirt). Our flying site is inland from the coast & in July/August temps exceed 40c, with high humidity.

mike3841

Hi to all,
I am pleased to say that my good friend Jason F has finished the install on my
Viperjet, he did let me paint the inside of the fuselage grey though.
As can be seen from the pictures I will be using a 14ch Futaba rx (14 sg Tx)
with an igyro 3e. Wing tip lighting by Braincube, this will help landings in poor
viz. This is switched with landing flaps. Fuel system is as devised by Mark V
and consists of two smoke tanks feeding a single 1.5L main. A UAT is just in
front of the engine witch is a Jets Munt 100XBL.
Flight servos are Savox, 20k for elevator and flaps and 11k for the rest.
The kit has been great, the wing fit was a bit tight but I eased the sockets in
the wings with wet and dry wrapped round some dowel, and put a very slight
taper on the Alum pins. Don't expect to fly it until I get back from our holiday
down under, by then I hope the weather will be better!

All the best Mike.

Jgwright

After some ribbing from Sean amongst others I fitted a Trudo 140 (Simjet 3000) to my Viperjet instead of the old 1700 I had installed for the flights up to date. I thought that it would be interesting to compare the same plane with the 2 engines. As usual Dave Wilde flew for me. Takeoff was noticeably shorter and vertical performance was better (very good). Level flight was very little difference as the airframe is very slippery and if you make smooth turns the airspeed does not bleed away very much. Flying was mostly done between 1/3 and 1/2 throttle with full throttle being only used in vertical manoeuvres and in takeoff. The plane used 1.5 litres in 8 minutes, much the same as with the old 1700. Dave found the residual thrust higher with the 3000 and made landing a little more difficult. he overshot the landing for the second flight (during a cross wind) and did a go around for a second attempt. In conclusion I would say there is very little to choose between engines unless you are flying off grass, but landings may be a little harder with the more powerful engine.

John

Jim Cattanach

Video of my Jet legend Viper jet flying last Saturday. Must grease the brakes some more to stop them grabbing.
This is about the fourth flight. Power is a Merlin VT80.
Thanks to Costa for taking the video.

https://www.youtube.com/watch?v=Y1BM7MwSbmY

mikedenilin

My Feedback: (67)

John, how much flaps do you carry at landing? I have a 140N engine with higher residual thrust, but I use about 75 degrees flap setting and crawl setting and it lands slow and controllable. Mike

gsmarino2000

My Feedback: (2)

Thanks for posting, Jim. I love the way this scheme looks in the air!

Greg

Jgwright

Mike

I set the flaps as far down as I could get them, about 75 degrees. As I mentioned there was a cross wind and that will not have helped.

John

gsmarino2000

My Feedback: (2)

Just got mine yesterday. Generally excellent workmanship as others have described. Paint is really impressive. Wing tube and wing mounting pins will need a bit of work so that it goes together smoothly. Can't wait to get it in the air!

Greg

extra300s

Hi essyou35

Just a few questions to you. Would a 32oz duro tank (950ml) tank be sufficient upfront intead of the 1500ml JL one if I use the two smoke tanks as fuel tanks? I will also run a UAT upfront. Want to keep the weight of this jet down to ensure a lighter wingloading. But don’t want to end up on the tail heavy side either. Going to install a 10kg Kingtech. Or sould I use a 1200ml 40oz tank instead?

Secondly the nice mod you do to the tank with the two barbed nipples installed. How do you ensure it is installed airtight? Do you use a seal or some sort of compound? Or just the nipple with a nut on inside of tank with locktite?

On my first viper which I unfortunately had to sell, I found with the tanks at stck location and no smoke tanks the plane was very nose heavy. Required way to much up elevator with inverted flight. Hence me wanting to go the same roete as you utilizing the saddle tanks. Also it provides more space on the tank tray this way.

Thanks
Karl

javier161

Hey guys, what gyro would be the best option for the viperjet?

Thanks

Jason R.

No Gyro needed, just a good left and right thumb is all that is needed..

Jason

mikedenilin

My Feedback: (67)

Hi Javier,

Most of us use Cortex Gyro. We think it's the best for this Viper.

http://www.globaljetclub.com/index.p...roduct_id=2605

Mike

gsmarino2000

My Feedback: (2)

Guys,

My VJ came with the Spark UAT, which I was planning to use. Upon examination, this is just a small tank with a felt clunk. I'm used to the BVM or Hansen approach with a kuss filter sock. Is anyone using the Spark UAT? Any feedback/comments? I assume it must work; Jet Legend / Spark has been in the business a while and seems to sell quite a few turnkey jets.

Thanks,
Greg

mikedenilin

My Feedback: (67)

Hi Greg, Just use the stock Spark UAT. It works as good as any UAT. Mike

RIGDESIGNER

Hi all, this is my first jet build and the progress so far. Had a successful first static engine run last weekend. need to balance and program a few mixes in
and should be ready for a maiden flight pretty soon. Power is Wren 80i Kero & setup is JR Xbus through convertors with Hitec 7955TG`s all round. I have the new JR Axis Xbus gyro waiting
to go in eventually but wanted to get to know the Viperjet without it first. Thanks to Jeff at Zedjet for unlimited advice.


Cheers


Howard