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C-ARF Ultra Flash build Thread + Video

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Old 06-15-2017, 11:18 AM
  #5801
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Fixed my antenna!

anyone have a jet dashboard or instruments they want to part with? Working on the cockpit
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Old 06-17-2017, 03:39 AM
  #5802
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Quote:
Originally Posted by setxws6 View Post
BTW I'm a new owner of a 1 owner used UF in Navy scheme. I've got 8 flights on it already and it's a dream to fly! Mines powered by a Jet Central Rhino KS so it's FAST. I've GPS it around 260 without trying hard at all!!! It's like its actually on rails, and landings are so easy. A+ CARF!
I like that scheme and am considering it if I buy a second flash. I would ask if they would do the fuse in yellow. I hope they would do a color swap. What combination of fuel tanks are you running and what is your flight time with the Rhino? I will be test flying my Cheetah SE powered UF next week and the fuel system is haunting me. I am worrying about flight time and how much unusable fuel will be in the main tank. I am running the saddles, main, 11 oz hopper and 4 oz UAT. I am prepared to add the wing tank if need be was hoping to avoid that.
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Old 06-17-2017, 10:41 PM
  #5803
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Quote:
Originally Posted by MaJ. Woody View Post
I like that scheme and am considering it if I buy a second flash. I would ask if they would do the fuse in yellow. I hope they would do a color swap. What combination of fuel tanks are you running and what is your flight time with the Rhino? I will be test flying my Cheetah SE powered UF next week and the fuel system is haunting me. I am worrying about flight time and how much unusable fuel will be in the main tank. I am running the saddles, main, 11 oz hopper and 4 oz UAT. I am prepared to add the wing tank if need be was hoping to avoid that.
My UF is running with the main tank, wing tank and 4oz UAT. No saddle tanks here. I have my timer set on 4:20 secs and come down with about 1 inch in the main tank. So I could/may push it to 5 minutes but I really like having the reserve available. Previous owner claimed 6:30 minutes but I believe he was just about running it dry. The Rhino KS is a very thirsty turbine, but in exchange I get a UF that's ridiculously powerful and fast. So I'm hauling the mail those 4:30 minutes I'm flying typically. I'm not sure how the Cheetah compares being a slightly smaller can with more rpm to deliver same thrust. I've seen people use 80-100N turbines but they struggle to get in the 200's it seems.
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Old 06-18-2017, 02:23 AM
  #5804
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I've got a Atj 190sv in my ultraflash using all tanks 5.2L got my timer set at 6:30 normally land with a full wing tank.
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Old 06-18-2017, 05:02 AM
  #5805
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Thanks for the data guys! The Cheetah SE burns 22 oz per min at full throttle.I think the Rhino KS is burning about 18 oz per min (a figure I saw on the net). Although I have 140 ounces of fuel on board I am calculating that I only have 114ounces usable. The 4 ounces in the UAT and the rest of the unusable fuel being in the main tank. At 22 oz per min, I am empty in 5 min. Two things I am hoping for: First that I can actually draw more fuel from the main tank than I did with my test on the ground. Hoping that the fuel will be pushed back in flight allowing me to draw more than on the bench. Second I am hoping that I can discipline myself to not fly at full throttle all the time. That's a big challenge given my flying style. In the end I may have to get the wing tank. Worrying about fuel or having to restrict my flying style or time is not fun. Especially at a busy Jet Rally. I will know the answers to these questions next week. I think I'll set the timer on the maiden to 4 min. and keep the power back.
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Old 06-18-2017, 05:56 AM
  #5806
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Jettech main and saddle tanks in mine - 116oz total, not including the 4oz air trap. Merlin 140 powered and I have my timer set on 9 minutes and I land with around 40oz remaining, which is about half of the main tank, or about 1 inch of fuel in the tank. I used to get 9 mins with my 17lb Wren SuperSport at full throttle continuously with the same reserves. The Wren couldn't top 200mph though.

High power (but not full continuously with the Merlin 140) for over half of the flight then easing up for the remainder. I actually fly to fuel quantity, not a timer, with Bingo at 60oz and landing around 40-45oz, but it is very consistent on time also.

Paul
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Old 06-18-2017, 03:30 PM
  #5807
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Thanks Paul.
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Old 06-18-2017, 04:41 PM
  #5808
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Quote:
Originally Posted by MaJ. Woody View Post
Thanks for the data guys! The Cheetah SE burns 22 oz per min at full throttle.I think the Rhino KS is burning about 18 oz per min (a figure I saw on the net). Although I have 140 ounces of fuel on board I am calculating that I only have 114ounces usable. The 4 ounces in the UAT and the rest of the unusable fuel being in the main tank. At 22 oz per min, I am empty in 5 min. Two things I am hoping for: First that I can actually draw more fuel from the main tank than I did with my test on the ground. Hoping that the fuel will be pushed back in flight allowing me to draw more than on the bench. Second I am hoping that I can discipline myself to not fly at full throttle all the time. That's a big challenge given my flying style. In the end I may have to get the wing tank. Worrying about fuel or having to restrict my flying style or time is not fun. Especially at a busy Jet Rally. I will know the answers to these questions next week. I think I'll set the timer on the maiden to 4 min. and keep the power back.
22oz/min?! Wow, that seems like a lot. My P120SX is older technology and sucks about 12oz/min. I have my timer set at 8:45 and run the main tank+wing tank. Used to have a 160 in there, but the flight times sucked and it didn't seem to go any faster than my other 120 powered flash so I opted for the 120SX
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Old 06-18-2017, 05:13 PM
  #5809
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I was shocked at the 22oz per minute also but I verified it with Jet Central in the Jet Central Forum. It really Sucks pun intended!
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Old 06-24-2017, 06:52 PM
  #5810
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So what's the consensus on aileron differential? I am getting wobbly vertical rolls. Depending on who I talk to or what I read on RCU, some believe you need more up than down while others say you need more down than up. The manual says more down than up and I seem to buy into the idea that since the surface area of a lived hinged surfaces gets smaller going down you need more travel. My Flash is flying incredible (more on that later) but the vertical rolls are horrible.
thanks!
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Old 06-24-2017, 09:34 PM
  #5811
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As the manual, more down than up as you say. From memory at the tip about 1/16" more down
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Old 06-24-2017, 10:33 PM
  #5812
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Yea couple mm extra on down side. I basically got it right the first time and haven't had to touch it. Rolls great
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Old 06-25-2017, 01:30 AM
  #5813
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Thank you both!!
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Old 06-25-2017, 04:40 PM
  #5814
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Ok my Flash came in at 23.7 lbs dry. Balanced at 232mm. Forgot to put fuel in the UAT when I did and she needs 5.7oz in the tail. Looks like no cockpit kit and pilot!! (That would be another 5.9oz with the tubs and pilot in the nose!!)Kingtech 9.9 3800 ecu pack and twin Jeti 5200 packs for Rx and electric gear in the nose. She was nose heavy for sure!

If I put the tubs and pilot that would be 11.6oz in the tail to get the CG at 232mm!!!

thoughts!!??
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Old 06-25-2017, 05:58 PM
  #5815
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Two 5200 mah batteries?!?! That's too much. Ive got two 2500 mah on my receiver and barely use much mah at all after 3-4 flights
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Old 06-25-2017, 07:32 PM
  #5816
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I was following some builds with the electric retracts and ordered these. They are 8oz each with trays. The 2900 packs come in at 4.5oz each. I was just conservative with the electric gear and redundancy for the rx. If the 2900's will work, I am all in! Already posted the 5200 packs for sale! LOL
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Old Yesterday, 02:50 AM
  #5817
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Better to remove weight if you can than add weight to get the cg right. But yea I've got two 2500mah A123 LiFe on my receiver and a 3s 1300mah lipo for retracts/brakes and it's more than enough for 3-4 flights. Now if you were flying 10-12 flights every time you went to the field then yea you'd want some monster batteries but 3-4 flights is usually the most I can manage to get at my field depending on conditions.
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Old Yesterday, 02:56 AM
  #5818
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Really!? I use a Powerbox Sensor switch in all my Flash models and on 2 x 2200 2s Li-Po packs, I get 12-13 flights per charge.
Each pack is giving out 120-130mAh per flight.

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Old Yesterday, 03:29 AM
  #5819
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Yea 120-130mah per flight sound about right. So yea you could fly quite a bit on a 2200-2500 mah battery!
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