CARF Ultra Flash Evo build thread +

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01-24-2024 | 10:38 PM
  #751  
You can buy RCJI each issue like everyone else and read the results. They are as close as possible because all results are adjusted to for common atmospheric conditions, tested on the same thrust rig, same fuel type etc.

Looking through the table there are a lot that don’t make the thrust figures stated on the manufacturers web sites, fuel consumption is one thing I completely ignore from everyone, I guarantee even through a batch of turbines the fuel use varies. Those manufacturers that ensure the turbine make at least the stated thrust have to adjust mechanics and sometimes electronic parameters to reach a figure they are already struggling to make, so more fuel will be used by these units.
Anyone who has built turbines will know 10 identical sets of parts produce turbines that do not run the same. Smaller the engine, more fussy they are.

JetCat like to have some margin, so when you operate their engines away from sea level perfect conditions you still get something like the stated thrust, I guarantee some manufacturers engines are way below once it gets hot and high.
End of the day you want a reliable turbine, that is number 1, everything else is secondary

JetCat fanboy…are you new to this rodeo? Yes, I’ve been involved since 1996…before they started full production 25 years ago this year.
Reply 1
02-01-2024 | 09:24 PM
  #752  
What servos are everyone using? Apart from the old usual JR and Futaba mentioned on the threads here.

I know that flash comes with 20mm wide servo slots, will 15mm wide servos do the job? i guess ill have to add spacers?
Can someone share servo install photos of the wing or tail.

Came across these KST HV servos that look like great options.
KST 115 2212 - 40.5mm*15mm*34mm / 25kg torque at 8.4 v / 53g
A20-3813 - 40.5mm*20mm*38mm / 48kg at 8.4v (Overkill?) / 72g




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02-01-2024 | 10:16 PM
  #753  
Tailplane you could use 15mm servos if you redrill the mounting angle brackets. Rudder needs full size.
Wing you would need to remake the mounts, but it could be done. Remember it’s not just servo torque, the 15mm servo has smaller gear teeth, so they are weaker.
In the U.K., MacGregor servos are the popular choice.



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02-01-2024 | 10:24 PM
  #754  
Thanks dave,
Will probably look for 20mm wide servos to avoid complications.

i hope 25kg torque is enough?
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02-02-2024 | 01:40 AM
  #755  
More than. It was designed around the JR 8411…11kg.we have been near 300mph with those servos.

Dave
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02-02-2024 | 09:59 AM
  #756  
Quote: You can buy RCJI each issue like everyone else and read the results. They are as close as possible because all results are adjusted to for common atmospheric conditions, tested on the same thrust rig, same fuel type etc.
So maybe in the great British Commonwealth, you can download a copy, but it's not available here in Canada.
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02-02-2024 | 11:46 AM
  #757  
Quote: So maybe in the great British Commonwealth, you can download a copy, but it's not available here in Canada.
Really! Makes no sense, let me talk to the editors
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02-03-2024 | 03:35 PM
  #758  
Had it confirmed you can down load and subscribe in Canada.
They say Google Pocketmags RCJI
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02-06-2024 | 02:55 PM
  #759  
bump
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02-15-2024 | 09:49 PM
  #760  

Are the Ultra flash evo stock tank fittings are being updated to such o ring style with push in connector? This is a Rebel classic tank of a friend that came in with new style fittings, i am aware Flash cannot have a vent line on the top, so should i expect old style fittings with the rubber thing where main tank line and the vent go in together and the copper tube has to be bent upwards for vent ?
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02-15-2024 | 10:03 PM
  #761  
Yes, they come with the new style. The vent insert is in the bottom of the tank with a long tube going to the top of the tank…clever people at CARF.
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02-16-2024 | 01:36 AM
  #762  
Quote: Yes, they come with the new style. The vent insert is in the bottom of the tank with a long tube going to the top of the tank…clever people at CARF.
Thanks Dave, this is awesome.

I have also requested the same via email on my order.
Hope i get the new fitting.

cheers
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02-16-2024 | 02:37 AM
  #763  
Quote: Thanks Dave, this is awesome.

I have also requested the same via email on my order.
Hope i get the new fitting.

cheers
Cmjets has been doing a low vent with a tube for the Ultra flash for a long time, I have used that tank…I’m sure CARF saw them and knew it was required for the UF….
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02-16-2024 | 12:55 PM
  #764  
….
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04-17-2024 | 08:20 AM
  #765  
Hi,
i have collected info on servo arm lengths from the Evo manual.
Although this is not a huge topic of discussion but just want to get everything right on this build.Flaps 16mm
Aileron 19-20mm
Tail 19-20MM
Rudder 20 - 25mm

Are these the total length of the servo arms from tip to tip?
Or the length from the servo centre hub till the outter hole where the push rod will be linked?


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04-18-2024 | 01:58 PM
  #766  
Servo centre screw to actuation hole
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04-18-2024 | 10:18 PM
  #767  
Could someone provide the length of servo extensions needed for the elevator and rudder servos? I have an UF on the way and these are the last things on my list to get.

Thanks!
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04-19-2024 | 12:04 PM
  #768  
Will depend on the routes you take! 95% of people now crimp their own leads to exact lengths.
60” will do the elevators. Rudder needs around 50”
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04-19-2024 | 12:11 PM
  #769  
what are some good options for retracts. electric preferred

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04-19-2024 | 07:27 PM
  #770  
Quote: what are some good options for retracts. electric preferred
Only 2 options, Electrons are overall best and JP hobby/
If you scroll up couple of posts you will find lots of info about retracts from my questions
answered here
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04-19-2024 | 09:42 PM
  #771  
thanks for the response,
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04-20-2024 | 10:53 AM
  #772  
Quote: thanks for the response,
stay away from JP, Electrons are only about 100 bucks more but much stronger, more reliable and offer adequate braking power
Reply 1
04-21-2024 | 07:37 AM
  #773  
Very nice! Are these the AMP 20 pin connectors from Aeropanda?


Quote: this is how I just did mine. When the wing sits up there it holds the wires pretty snug. After plugging it in, I feed the wires back into the canopy area while seating the wing.


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04-21-2024 | 07:46 PM
  #774  
Yes these are AMP connectors. You can get these from Aeropanda, or with a little legwork, you can source them yourself from other places like Digikey. That is where I got them when I rewired Andrew's Flash after purchasing it.


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04-21-2024 | 07:50 PM
  #775  
Quote: Yes these are AMP connectors. You can get these from Aeropanda, or with a little legwork, you can source them yourself from other places like Digikey. That is where I got them when I rewired Andrew's Flash after purchasing it.



Thanks for the info.
Does the connector lock in really nice after connecting both the ends?
I do see the locks on the end of the pins, hoping it locks in real tight.

I am going to use the powerbox standard premium cables (not the maxi) i see they are quite thin and i will have to add a heatshrink to make the wire diameter bigger to be able to crimp on the pins.
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