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Eflite Viper too heavy

Old 02-27-2021, 09:55 AM
  #26  
solentlife
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Originally Posted by quorneng View Post
jangodog
My own guess is that none of the changes you have made would be expected to stop it flying, although each would degrade performance a bit, but all together might be different.
I would imagine the centre burner unit is heavier that the motor cowl it replaces and iit is not as aerodynamic as the motor cone. In addition its lead is directly in the fan airflow.
The twin wheel undercarriage will almost certainly be heavier and will also add a bit of drag both extended or retracted..
The added triangle cowling looks ok unless it is in the narrowest part of the duct in which case it could be restricting the fan airflow.
The extra 'decoration' on the tail pipe will have added some weight and more importantly it is right at the back so could have effected the CofG.

The Viper is described as having an 'adequate' performance rather than being a 'rocket ship' so it is possible it doesn't take that much to have a significant effect.
Just my two penníorth.
+1

Guy in our group had a Viper ... he took all wheels off it and hand launched it ... it flew well ..... he did eventually up the battery in it ... it was the original 3S / 4S Viper from some years ago.
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Old 02-27-2021, 07:03 PM
  #27  
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I get the message. Iíll start with gluing the nose back and remove one of the twin main wheels. And if this isnít enough i might get me a new Viper instead.
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Old 02-27-2021, 09:44 PM
  #28  
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You could take off all wheels .... then bungee launch it ... or if they are retracts - keep them up and bungee ...
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Old 02-28-2021, 11:20 AM
  #29  
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Yes, good tips there. Think i'll keep the wheels on for now Thank's
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Old 03-01-2021, 09:19 PM
  #30  
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It looked to me like you had adequate speed for take-off. Just not enough elevator. Check your CG. It won't rotate if you have moved the CG too far forward.
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Old 03-01-2021, 10:47 PM
  #31  
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Originally Posted by Panther View Post
It looked to me like you had adequate speed for take-off. Just not enough elevator. Check your CG. It won't rotate if you have moved the CG too far forward.
Or if the mains are too far behind the CG. I had that problem on my Vulcan.
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Old 03-02-2021, 09:45 AM
  #32  
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Originally Posted by quorneng View Post
jangodog
My own guess is that none of the changes you have made would be expected to stop it flying, although each would degrade performance a bit, but all together might be different.
I would imagine the centre burner unit is heavier that the motor cowl it replaces and iit is not as aerodynamic as the motor cone. In addition its lead is directly in the fan airflow.
The twin wheel undercarriage will almost certainly be heavier and will also add a bit of drag both extended or retracted..
The added triangle cowling looks ok unless it is in the narrowest part of the duct in which case it could be restricting the fan airflow.
The extra 'decoration' on the tail pipe will have added some weight and more importantly it is right at the back so could have effected the CofG.

The Viper is described as having an 'adequate' performance rather than being a 'rocket ship' so it is possible it doesn't take that much to have a significant effect.
Just my two penníorth.
Yes, it all adds up. Iíll keep the centerburner and bec on and strip the twin wheels to singles again. The tailpipe iíd might toss too. Thankís for your input.
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Old 03-02-2021, 10:52 AM
  #33  
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Don't know what happens with the apostroph marks in my text? Maybe some Danish keyboard layout
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Old 05-13-2021, 07:44 PM
  #34  
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I thought I was the only one who noticed it .. I have one at home but whenever Iím to take it to the field I have to call my son to help me out because it too heavy .. but trust me itís a wonderful jet ..
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Old 05-14-2021, 12:17 AM
  #35  
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Welcome to WF Fastandlow.
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Old 05-18-2021, 02:31 PM
  #36  
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Originally Posted by Fastandlow View Post
I thought I was the only one who noticed it .. I have one at home but whenever Iím to take it to the field I have to call my son to help me out because it too heavy .. but trust me itís a wonderful jet ..
Yes, you are so right had a lot of flights on this wonderful bird
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