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Sep 16, 2013, 03:00 PM
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I'm afraid I will not maiden it this weekend. I was making the final tests today with the retracts and my front retract stopped working. I have disassembled it and it seems an electronic problem as the motor only works in one direction. Let's see how long it takes to have it repaired.

JoanC
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Sep 17, 2013, 07:42 PM
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1.7m Viper Building instructions


I have been give a 1.7m Jet Tang Viper to build for a friend. I have figured most things that need to be done, but I still have a few questions.
1 Tailpipe, I assume the roll of Mylar is for the tailpipe, Am I correct. I have a StuMax 120mm fan and it fits the intake adaptor OK, I was just wondering about the tailpipe. I was going to use aluminium tape to hold it together and to the fan.

2 Tail Servos, I can see how they are mounted. Can I assume that the internal blocks for the horns are in the correct position in the elevators?.
I was going to use Hitec 5245MG servos, Any comments

3 Tail mounting. Do I just have some small screws into the tail spar to hold the tailplane halves on to the spar. If they were glued on you could never replace the servos. Ok, I know that is a dumb question. Same for the wings? .

Is there a build instruction anywhere on line?

Thanks

Tom Watson

Sydney Australia
Sep 19, 2013, 07:15 AM
Registered User
icicles's Avatar
Quote:
Originally Posted by tommywatson View Post
I have been give a 1.7m Jet Tang Viper to build for a friend. I have figured most things that need to be done, but I still have a few questions.
1 Tailpipe, I assume the roll of Mylar is for the tailpipe, Am I correct. I have a StuMax 120mm fan and it fits the intake adaptor OK, I was just wondering about the tailpipe. I was going to use aluminium tape to hold it together and to the fan.

2 Tail Servos, I can see how they are mounted. Can I assume that the internal blocks for the horns are in the correct position in the elevators?.
I was going to use Hitec 5245MG servos, Any comments

3 Tail mounting. Do I just have some small screws into the tail spar to hold the tailplane halves on to the spar. If they were glued on you could never replace the servos. Ok, I know that is a dumb question. Same for the wings? .

Is there a build instruction anywhere on line?

Thanks

Tom Watson

Sydney Australia

Hi Tom,
I just use normal cello tape inside and out on my thrust tube. Aluminium tape on the tube to the fan is okay. I also use clear cello tape from inside the tube to the outside of the fuse. As an extra safety.
Yes the wooden blocks are inside.. Sorry i don't use Hitech. I am using Futaba bls153 7kg torque.

I'd bolt the stabs on with the hardware included. Especially if you want to get a servo out. Do the wing differently, put a threaded stud in the wing t nut. Then use a large nut in the fuse.

Dig up the baby Jet T eng 90mm thread, it is basically the same build just bigger. Also you will find a manual there which is good enough for the big Viperjet. I'd go off Billy D information regarding c of g etc. He's definitely done plenty of flying with his turbine one. He's the man.

Hope this helps. Sorry for this, done it all through my phone

Chris
Sep 19, 2013, 11:00 AM
Registered User
Hi Chris,

Thanks, I have started to look through the 90mm build thread and it is all starting to make sense. I will start soon on the build and I am sure I will have more questions. I have built a few composite model in the past and I just wanted to make sure I don't make too many mistakes.
Regards

Tom Watson
Sydney Australia
Sep 19, 2013, 08:53 PM
Not a Drone pilot
lashmett75's Avatar
FYI...Tam is working on new ducting for the Viper. Mine is the ginnie pig. But with the updated ducting this will allow a much large fuel tank to be place between the 2 ducts.
He also has completed the same turbine conversion ducting on the Triple XXX.

I will try and get some pics next week when I swing by the shop.

James
Sep 23, 2013, 07:42 PM
DS JUNKY
What's everyone using for a rudder/elevator servos? All using JR DS3421?
Sep 23, 2013, 08:34 PM
Registered User
icicles's Avatar
Futaba brushless bls153 for me

Chris
Sep 24, 2013, 12:51 PM
Registered User
Hitec HS-7245MH for me

JoanC
Sep 24, 2013, 01:12 PM
DS JUNKY
Quote:
Originally Posted by JoanC View Post
Hitec HS-7245MH for me

JoanC
Did those fit okay? 16.8mm seems wider or as wide as the stabilizer?
Sep 24, 2013, 03:50 PM
Registered User
there is one big MINUS on this jet.. and the customers who are building it as turbine have this concern.. there is no hatch to see the turbine when it starts.. RARE but not impossible to happen is when a fire may start by the turbine and you need use your fire extinguisher
what happens then .. how do you have access to the turbine?
JTM needs to modify this part
Sep 24, 2013, 04:07 PM
DS JUNKY
You can see some over the top of the intake ducts with the canopy hatch off. You could also modify the bottom hatch with spring loaded pins or some other quick access retainer so you can start it with the bottom hatch open and keep a mirror under there if you wanted to see it further. Also let's not forget that this is an EDF model...
Sep 24, 2013, 04:15 PM
Registered User
Quote:
Originally Posted by Z06kal View Post
You can see some over the top of the intake ducts with the canopy hatch off. You could also modify the bottom hatch with spring loaded pins so you can start it with the bottom hatch open and keep a mirror under there if you wanted to see it further. Also let's not forget that this is an EDF model...
I agree.. but due to the fact that most are building it as turbine it should have a second version with a hatch.. The XXX does have.
I asked JTM if they could do a v2 with a hatch..
I'm currently in the talks to start a webshop with them. no intention to bash in BillyD thread bytheway. nothing is official yet and I'mi nthe other side of the Globe in Cyprus.
Billy is a great guy and been listening and answering questions from me and everyone else. to give you an idea how far away I am from my idea Im still not sure what servos I should use on flaps and ailerons
I'm building one of my own Paf Sting Evo and I'm using JTM retracts. got some good reviews on the latest versions.
Sep 24, 2013, 04:27 PM
DS JUNKY
Quote:
Originally Posted by pavlis View Post
I agree.. but due to the fact that most are building it as turbine it should have a second version with a hatch.. The XXX does have.
I asked JTM if they could do a v2 with a hatch..
I'm currently in the talks to start a webshop with them. no intention to bash in BillyD thread bytheway. nothing is official yet and I'mi nthe other side of the Globe in Cyprus.
Billy is a great guy and been listening and answering questions from me and everyone else. to give you an idea how far away I am from my idea Im still not sure what servos I should use on flaps and ailerons
I'm building one of my own Paf Sting Evo and I'm using JTM retracts. got some good reviews on the latest versions.
The nice thing is that there is plenty of room in the wing for any standard size servo so the sky is the limit. You could put a 480 oz/inch servo in there if you wanted.
Sep 24, 2013, 04:44 PM
Registered User
Quote:
Originally Posted by Z06kal View Post
The nice thing is that there is plenty of room in the wing for any standard size servo so the sky is the limit. You could put a 480 oz/inch servo in there if you wanted.
the ailerons don't need that much power.. so any size servo above 4-5kgs would be more than adequate. the elvators and rudder are getting stressed a lot and the flaps also ..
so that's good to know. standard size servos you got tons of options.
thanks for the answer.
Sep 24, 2013, 06:38 PM
Registered User
icicles's Avatar
I went with an 11kg servo for the flaps, it's a very tight squeeze. Set it up for 70 degrees, but can just about get 90 degrees lol. That should be like chucking a brick out the back.
It's a shame there doesn't appear to be more EDF's of this model. It's a very nice kit. And there are a huge amount of combinations available

Chris


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