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Another Skymaster Viper

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Old 01-13-2010, 03:29 AM
  #701  
NightSwan
 
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Default RE: Another Skymaster Viper

@Alessandro,

don't use those shims. Keep the turbine in parallel with the mounting rails, and align it with the pipe only.
I've talked with a lot of people about this, some with lots of viper experience

The intake seems to be off-center, thrustline with the rails and pipe in one line is ok and inline.

Hans
Old 01-13-2010, 04:00 AM
  #702  
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Default RE: Another Skymaster Viper


ORIGINAL: DelGatoGrande


ORIGINAL: Matt Chapman

....
Will an incidence + or - have an effect on the pitch of the plane based on power in flight? ...
Hey Matt
Yes it can have an effect!
like in prop planes we must fine tune the up down thrust of the engine.. same think in jets.
its like you having a vector thrust set up whrong...
start seting a degree lazer meter to zero on the wing ...then check engines mounts and pipe..

..but if Matt Chapman enjoy fly this toy untill now..then it needs no corection

forgive my poor english

Besides the problem of the thrust line another problem could be the heating of the tube. With the incidence of my mounting rails of the turbine the bottom of the tube will be much more hot the top and we are speaking about many degrees... am I becoming paranoid? [&:]

Alessandro
Old 01-13-2010, 04:06 AM
  #703  
Ali
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Default RE: Another Skymaster Viper

Mount the turbine to the rails as they are supplied. Then line the tube up to the turbine ( Straight ) All is fine. The heat is distributed evenly down the pipe ( Dont worry this is no fry eagle pipe ) There is no pitch change with power. I know it looks strange but all of the Vipers are like this and all work perfectly.
Regards Al
Old 01-13-2010, 04:19 AM
  #704  
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Default RE: Another Skymaster Viper

The Man spoke,the issue end
time to fly[8D]
Old 01-13-2010, 04:38 AM
  #705  
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Default RE: Another Skymaster Viper


ORIGINAL: NightSwan

@Alessandro,

don't use those shims. Keep the turbine in parallel with the mounting rails, and align it with the pipe only.
I've talked with a lot of people about this, some with lots of viper experience

The intake seems to be off-center, thrustline with the rails and pipe in one line is ok and inline.

Hans
Hans is impossible for me align it with the pipe.
I've done a scheme... terrible!

A

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Old 01-13-2010, 04:44 AM
  #706  
OttoKranz
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Default RE: Another Skymaster Viper


ORIGINAL: DelGatoGrande

The Man spoke,the issue end
time to fly[8D]
Ah ah ah
You are right!

Thanks you all.
Old 01-13-2010, 06:12 AM
  #707  
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Default RE: Another Skymaster Viper


ORIGINAL: f106jax


ORIGINAL: DENTO


ORIGINAL: kimba

HI All and John
I have finally finished the Viper no maiden as yet Temp here for the next week is going to be 39 to 41 C so there are fire bans in place
have done quite a few mods some from this forum and some of my own which I have posted. It has been a big help reading what you guys have done thanks for all of the posts I will post a few pics that may be of help to others
Cheers Bronte
VERY VERY NICE
Sorry about the fire ban as you know ours has been lifted, Talking to Chris Venter larst night and he is close to finishing his, So I shall leave my maiden untill we can do both at the same time in maryborough maybe early feb,Could be as many as 6 VIPERS at wangeratta, Talk to you soon bronte shall add some shots of my craddle .
REGARDS
JOHN
John,

Would you be good enough to post the dimensions of your carrier and templates of the front and rear fuselage cradles? Looks great!

Thanks,

HI GUYS
Shall post some shots of the craddle and try and explain
BOTTOM PLANK 2.4 MTS LONG X290 MM WIDE
BOTH FRONT AND BACK SUPPORTS 290MM WIDE 190MM H
MIDDLE SUPPORT 1800 X 90 LONG
I hope the shot will help you will have to allow for what ever tube you use apart from cutting templets and posting them by post this is the best I can do
REGARDS
JOHN
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Old 01-13-2010, 07:31 AM
  #708  
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Default RE: Another Skymaster Viper

Just a heads up chaps, if you do make a craddle don't leave your presious airframe on it for a long period of time, the paint will fade from UV exposure, but not under the straps, even under the bottom supports there will eventually be a colour difference, just thought I would mention it.

Mike
Old 01-13-2010, 03:19 PM
  #709  
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Default RE: Another Skymaster Viper

Be carefull with thrust angle and thrust line height. Can be confused . A boomerang has the thrust line very close to the (vertical)Cg , changing its angle a little don´t change its height a lot with respect to the Cg ,that´s what really counts.
Ask a harpoonII owner how easy is to get into problems with thrust trim .... I have seen it flip on take off.
Some cheap ducts can suffer from heat but normally thre is no problem,a lot of fresh air is bypassed into the duct.
Old 01-14-2010, 03:50 AM
  #710  
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Default RE: Another Skymaster Viper

When I had the second flight on my Viperjet, the canopy was destroyed in flight (pictures a few pages back).
I got a new piece of plastic from Skymaster (quick delivery!), and installed it, no problem.

However, today when cleaning the workshop, I looked at the old plastic, to see if a few pieces could be saved for other purposes, and I noticed that the plastic is VERY brittle at the edge where it was glued onto the canopy frame, just the slightest touch/twist, and it cracks! I cut a piece of it out, and tried on that, holds very well.
So the glue Skymaster uses for fixing the glass to the canopy frame makes the plastic brittle, and I wonder how long the canopies out there will hold ??
Any of you seen similar stuff ?
Old 01-15-2010, 06:20 AM
  #711  
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Default RE: Another Skymaster Viper


ORIGINAL: Ali

Mount the turbine to the rails as they are supplied. Then line the tube up to the turbine ( Straight ) All is fine. The heat is distributed evenly down the pipe ( Dont worry this is no fry eagle pipe ) There is no pitch change with power. I know it looks strange but all of the Vipers are like this and all work perfectly.
Regards Al
Ali,
with a friend of mine that is building another Viper we measured the difference of degree between wing and engine mount... 4 degrees!!!
Of course I swear I believe you (!!) about the strange absense of pitch change with power but what about the total power? Don't you think we can lose some of it?

Alessandro
Old 01-15-2010, 10:11 AM
  #712  
Duncan
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Default RE: Another Skymaster Viper

Alessandro

mine also looked strange when i put a straight line on the rails, as it does hit the bottom of the rear of the fuz. However i checked Ali's model which has the same angle of the rails, but the turbine lines up perfectly when bolted in place. I bolted mine onto the rails with the bypass and it also works out fine. Weird i know, i wasn't sure if it was an optical illusion to start with lol

Duncan
Old 01-15-2010, 12:27 PM
  #713  
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Default RE: Another Skymaster Viper


ORIGINAL: Duncan

Alessandro

mine also looked strange when i put a straight line on the rails, as it does hit the bottom of the rear of the fuz. However i checked Ali's model which has the same angle of the rails, but the turbine lines up perfectly when bolted in place. I bolted mine onto the rails with the bypass and it also works out fine. Weird i know, i wasn't sure if it was an optical illusion to start with lol

Duncan
Duncan

you are right, it seems in line, but you will agree with me that cannot...
I think we will find an answer here http://www.youtube.com/watch?v=NzlG28B-R8Y


Alessandro


Old 01-15-2010, 12:37 PM
  #714  
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Default RE: Another Skymaster Viper


ORIGINAL: cgroen

When I had the second flight on my Viperjet, the canopy was destroyed in flight (pictures a few pages back).
I got a new piece of plastic from Skymaster (quick delivery!), and installed it, no problem.

However, today when cleaning the workshop, I looked at the old plastic, to see if a few pieces could be saved for other purposes, and I noticed that the plastic is VERY brittle at the edge where it was glued onto the canopy frame, just the slightest touch/twist, and it cracks! I cut a piece of it out, and tried on that, holds very well.
So the glue Skymaster uses for fixing the glass to the canopy frame makes the plastic brittle, and I wonder how long the canopies out there will hold ??
Any of you seen similar stuff ?
I couldn't tell you. I have been waiting on a canopy for 2 months....
Old 01-15-2010, 02:04 PM
  #715  
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Default RE: Another Skymaster Viper

Sorry to hear about that !
I ordered one middle of december, and received it approx 1 week after !
Old 01-15-2010, 02:38 PM
  #716  
Duncan
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Default RE: Another Skymaster Viper

Yep it doesn't make sense, but Ali would notice if there was an issue with the thrust angle, if he can't notice any, there's no chance my dumb thumbs will lol
Old 01-15-2010, 10:20 PM
  #717  
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Default RE: Another Skymaster Viper


ORIGINAL: dubd


ORIGINAL: cgroen

When I had the second flight on my Viperjet, the canopy was destroyed in flight (pictures a few pages back).
I got a new piece of plastic from Skymaster (quick delivery!), and installed it, no problem.

However, today when cleaning the workshop, I looked at the old plastic, to see if a few pieces could be saved for other purposes, and I noticed that the plastic is VERY brittle at the edge where it was glued onto the canopy frame, just the slightest touch/twist, and it cracks! I cut a piece of it out, and tried on that, holds very well.
So the glue Skymaster uses for fixing the glass to the canopy frame makes the plastic brittle, and I wonder how long the canopies out there will hold ??
Any of you seen similar stuff ?
I couldn't tell you. I have been waiting on a canopy for 2 months....
Hi, dubd

please send your address with telephone number to this e-mail addres , [email protected]

we will send the canopy to you directly as soon,

Best regards

Anton
Old 01-16-2010, 01:39 AM
  #718  
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Default RE: Another Skymaster Viper

I measured also the thrust line and i have got also the same problem as before. ( I think it is alessandro )

I think i will change the front ( of the mounting rail ) so the thrust line will stay almost the same as Ali says. ( with no pitch difference )

and after the turbine and thrustpipe are straight.



Question to Anton,

mine clear canopy is also broken. ( it is really very brittle )

can you tell me how much i have to pay for a new clear canopy?

best regards,,

Peterjan

Old 01-16-2010, 10:19 AM
  #719  
OttoKranz
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Default RE: Another Skymaster Viper


ORIGINAL: Duncan

Yep it doesn't make sense, but Ali would notice if there was an issue with the thrust angle, if he can't notice any, there's no chance my dumb thumbs will lol
I agree with you Duncan, also I do not have the thumbs of Ali so is just to understand what's happening with this issue.[&:]

Ali, the friend of mine is Marco Loreti that sends you a greeting! He works with Luca Friggeri that spoke to me about you.

Alessandro
Old 01-16-2010, 10:43 AM
  #720  
Ali
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Default RE: Another Skymaster Viper

Hi Alessandro, Hi to all my Italian friends!
I dont think it makes a difference with the thumbs. My Viper also has the turbine looking like the turbine is angled up at the front. We measured the same with Duncan's model. No trim or pitch change. The Intake to the turbine angle is not straight but the turbine to tailpipe is level.
I am sure there is no problem to angle it either with Shims, but non of my Vipers have ever had a shim.
Good luck.
Regards Al
Old 01-20-2010, 03:16 PM
  #721  
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Default RE: Another Skymaster Viper


ORIGINAL: Ali

Hi Alessandro, Hi to all my Italian friends!
I dont think it makes a difference with the thumbs. My Viper also has the turbine looking like the turbine is angled up at the front. We measured the same with Duncan's model. No trim or pitch change. The Intake to the turbine angle is not straight but the turbine to tailpipe is level.
I am sure there is no problem to angle it either with Shims, but non of my Vipers have ever had a shim.
Good luck.
Regards Al
I will tell them! Thanks for the advice, I have to hurry up if I want to fly!!!
Ciao
Alessandro
Old 01-22-2010, 04:25 PM
  #722  
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Default RE: Another Skymaster Viper

SM Viperjets experts!

Guys I am about to start working on the fuse as I already finished all moving surfaces.

To my surprise the main large Kevlar tank doesn't fit at the bottom of the fuselage..... at the time I try to push the tank back to be under the intake bypass…. doesn’t fit….. it hits the intake.... it needs shim about 3 mm to able to fit. I am about to cut the tank in half at the seam…. remove the 3 mm and re glue the 2 pieces…. I know I can do a good job but what a pain.

Question? have any of you guys had that same problem…. or I am the only un lucky?

I am also considering moving that main tank on top of the bypass…… but I am concerned with having so much weight on top….. due to fuel.

By the way I measured the capacity of both Kevlar tanks and they are huge…. Bottom=92 onz and Upper 56onz…. total of 148 onz!

Any recommendations would be quite appreciated,

Gonzalo
Northern California
Old 01-22-2010, 05:00 PM
  #723  
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Default RE: Another Skymaster Viper

Gonzalo,

in my viper SM glued some mounts for the air-tubes at the back of the fuse-bottom - my tank would not slide all the way back. Could this be your problem as well? I removed the airlines and re-located them - tank fits perfectly now..

Good luck!
Hans
Old 01-22-2010, 05:49 PM
  #724  
PaulD
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Default RE: Another Skymaster Viper

I know of a builder who found his intakes were not glued in straight so had to do the same thing and put his tank on top of the intakes instead of under.

To make the best of this he just located his smoke tanks under the intake instead.

Check the picture, you can just see the front of the smoke tanks.

PaulD
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Old 01-22-2010, 07:34 PM
  #725  
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Default RE: Another Skymaster Viper

Thanks Hans and Paul for the info!

I am not planning so far to put smoke.... so I'm still on the side to cut the tank and redo the work.... is very little what I need to remove.... I am a little hesitant to have all that weight hi in the fuse...... unless I do most of my flight inverted
I still curious how many had that issue.

Regards,

Gonzalo


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