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C-ARF Ultra Flash build Thread + Video

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C-ARF Ultra Flash build Thread + Video

Old 09-28-2014, 01:48 AM
  #4426  
Dave Wilshere
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I have flown several with the P-100 and they do feel lighter, although I don't find an issue even with the heaviest UF I have flown. The energy retention is better with the heavier set ups. Flight times are probably longest with the P-160 turbines! You are on full gas for much less time (unless you are a nutter ;-), The smaller turbine you tend to be on full power more when the turbine is at its least efficient. I've watched Jame fly his and he has the throttle use of a helicopter pilot (means he can use the throttle stick actively) and uses the momentum to the maximum, for long flights.
I'm going to build another UF for myself soon and update the set up with a P-140Rxi which to me is the ideal set up.

Throttle response is not as critical as people think! Its all noise (giving some false relief) the draggy airframe still has to accelerate, probably not much faster than the old turbines spool up at...
Old 09-28-2014, 08:36 AM
  #4427  
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Originally Posted by mtnflyer14
I set the CG per Dave's instructions (220-225mm back from wing/fuselage root with gear up) and was able to get it within that range by just moving my batteries around in the forward pockets. I have two 6.6 LiFe batteries for receiver/servos and I think my ECU battery is a 7.4V 3400 MaH battery. I also think I had the UAT full, other tanks empty when setting the CG. In the UF update on CARF's website (that Dave wrote) it has a picture of the approximate CG location. I am not a very experienced jet guy, but the recommended CG seems to work for the kind of flying I'm doing.
Regards,
Gus
I just signed up to RC Universe because of your post. I purchased a UF 3 years ago, I own a lot of H9 & Segual crafts. This is my first jet, I told the man I ordered it from "send me everything needed except kerosene". When I received my UF the manual shows a different wing and the CG showed "360 - 370mm" from the back of the wing (a round tubular piece) forward to the CG. I attempted to make a couple calls (couldn't get response) because the wing shown certainly wasn't what I purchased. Anyway, guessing an approximate CG it ended up that empty of fuel, if I removed the canopy, a balance act starts on its main legs, falling more towards the elevator. I filled it up with fuel and air, put the canopy on and fired it up (P100), I held the brake switch, flipped it to full throttle and nervously let go of the brake switch and let it rip. What a rush. During that flight it took a few up clicks to make it feel familiar, which up clicks to me indicate nose heavy. After my 8 minute timer went off, my nerves then were requiring a respiratory therapist (haha) knowing that around $8000 was going to come down no matter what. I bounced the plane like a super ball and ended up breaking one of the 6mm gear studs. So, using 225mm from the front of the leading edge - I'm right on but as I said, the plane does a balance act when the canopy is removed and because of the front gear spring, seemingly super stiff and without damping, there is hardly any weight on the front gear (meaning, if you get the spring to compress at all - its going to look look like a porpoise) and I find it hard to land without bouncing the front end up and doing a real rookie looking landing. Although no one around here flies so I'm solo and I don't like what it looks like!!
So I am wondering if your UF has commanding weight on the nose wheel or is it feathery weight?

ps, I also have a good method of grinding flats (I read some posts of "impossible") that one day I should picture and share. Also I simply bought a box of 100, 6mm x 40mm dowel pins $45 MSCindustrial.com part 03835675. Hard as diamonds and they to break off just as good as the originals!! I bought these because I didn't know where to shop for new ones.
Old 09-28-2014, 09:47 AM
  #4428  
Dave Wilshere
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The balance of 220-225 is certainly a safe position, I balanced the new model I test flew on Friday at 225 header full and a small amount of fuel in the main fuse tank only. I'd say this felt slightly nose heavy in medium speed flight rolls. Undercarriage set up depends on the type, the original factory set we nearly all use in England has more trail than some of the other options. So the weight on the nose wheel will be much higher.
Landing wise, I can land the UF on the mains with the balance anywhere between 220 and 235mm ( a range I have flown UF models) The customer has been out with his UF today, waiting to find out how he got on with his first flights

Dave
Old 09-28-2014, 12:06 PM
  #4429  
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Shmagma

Bouncing means landing speed to high. Set up a little crow, about 4-5mm and a little bit more down offset on the elevator. This will help slow down the plane during landing because of the higher alpha like your H9 prop aircrafts do.
I know this is not Dave his style of landing but crow helps when you are used to high alpha style landing.
Old 09-28-2014, 01:21 PM
  #4430  
Dave Wilshere
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There is enough drag from the flaps, just increase the flap angle! No need to reduce wing lift!

Dw
Old 10-04-2014, 05:38 PM
  #4431  
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QUESTION ???

I am currently building my UF, I have had quite a time trying to get the saddle tanks (Kevlar upgraded ones from Jet-Tech) to work with the inlet duct/bypass setup, It is super tight in there what a pain.
When I put my wing on, the front pins go in great, but it does not lay flat against the fuselage rails, it sits up just a little, maybe about 3/16 inch. If I push down on the rear of the wing it will go down like it is supposed to, I don't have to push super hard, but I do have to push. If I let go it will pop back up. If I installed the bolts, it would definitely pull the wing tight against the fuse, and hold it, like it is supposed to be. So I started pulling stuff out to see what was causing the interference, I removed the turbine, then the bypass, and still had the issue, I then removed the inlet duct that connects the inlets to the bypass,, That is what is causing the interference,,
SO my question is this,, Do you believe this is a problem?? If so then my only action is to not run the inlet duct with the bypass, it is not bowed up, and sits flat agains the inlets like it is supposed to.
I was told it would be best to use the bypass system, because it helps keep the turbine cooler, and gives more performance,, I am still fairly new to this side of the hobby, My new ultra flash is my second jet, and I want it to be right, so I am asking for advice on this,,, as always Thanks
Ronnie
Old 10-04-2014, 07:21 PM
  #4432  
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Hi Ronnie,
I had a similar problem trying to get the inlet duct in and thought it wasn't worth the muckaround.
I'm not sure if you get that much benefit out of the bypass when the wing and saddle tanks give it a good shape anyway.

But I may try fitting the bypass later down the track to see if it will be a bit quicker.
Cheers
Pete
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Old 10-05-2014, 12:33 AM
  #4433  
Dave Wilshere
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Ronnie

even with the std duct this can happen, run the motor a few times and the heat changes all of the epoxy moulding shapes and then it settles. I have seen them with 3/8" at the back and its no problem.

Nothing to worry about

Dave
Old 10-05-2014, 01:49 AM
  #4434  
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Originally Posted by cbooth1979
Funny you should ask that I was going to post the same thing. Ive been flying mine with an early P-120 for about 20 flights and have been very happy with the plane overall. I just didnt like the slow throttle response of the older engines. I had a Kingtech 100G sitting around so im going to swap motors and try it out with a smaller engine. Going to fly it Sunday so will see!

Really looking forward to hear how it worked out!

That's exact the engine i got on order for my new UF.
Old 10-05-2014, 03:09 AM
  #4435  
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Guys how badly does this plane react if it's nose heavy. My cof g is 215 . I'd prefer not to add more weight to tail and I have no room to shove stuff in around the saddles.. I maybe able to use lighter batteries once I see the usuage of the tech inside on flights. I have some lighter batteries and they bring me to 220. But are only 1800 ma each and I have hv brushless servos throughout. My current batteries are 2650 lipo 2s.. Turbine is 3800 life 3s. I could lower the turbine bty size ... It's a p140rx

if I major refit I could change it but I'm over the build for now and want to fly....

ive flown nose heavy planes before but they only detract from a nice slow landing. I'm not sure how the jet will react.

thoughts?
Old 10-05-2014, 04:24 AM
  #4436  
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Mine was way nose heavy on first flights, no problem at all,No stress just fly it and see if you want change it afterwards if you want to.
Old 10-05-2014, 06:15 AM
  #4437  
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Originally Posted by SR117
Guys how badly does this plane react if it's nose heavy. My cof g is 215 . I'd prefer not to add more weight to tail and I have no room to shove stuff in around the saddles.. I maybe able to use lighter batteries once I see the usuage of the tech inside on flights. I have some lighter batteries and they bring me to 220. But are only 1800 ma each and I have hv brushless servos throughout. My current batteries are 2650 lipo 2s.. Turbine is 3800 life 3s. I could lower the turbine bty size ... It's a p140rx

if I major refit I could change it but I'm over the build for now and want to fly....

ive flown nose heavy planes before but they only detract from a nice slow landing. I'm not sure how the jet will react.

thoughts?
I think you are better off getting the cg further back, especially if you like to do a lot of 4 point or slow rolls. I think a forward cg will increase your rotation/landing speed & reduce elevator effectiveness. Probably a silly question, but do you have a batt far forward in the nose that can be dropped into one of the batt pockets? Maybe someone else who has tried that cg will chime in, but I'd take the extra weight in the tail to get cg correct & reduce inflight aerodynamic forces over a few ounces less overall weight.
my 2 cents
Old 10-05-2014, 01:27 PM
  #4438  
Dave Wilshere
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Originally Posted by SR117
Guys how badly does this plane react if it's nose heavy. My cof g is 215 . I'd prefer not to add more weight to tail and I have no room to shove stuff in around the saddles.. I maybe able to use lighter batteries once I see the usuage of the tech inside on flights. I have some lighter batteries and they bring me to 220. But are only 1800 ma each and I have hv brushless servos throughout. My current batteries are 2650 lipo 2s.. Turbine is 3800 life 3s. I could lower the turbine bty size ... It's a p140rx

if I major refit I could change it but I'm over the build for now and want to fly....

ive flown nose heavy planes before but they only detract from a nice slow landing. I'm not sure how the jet will react.

thoughts?
The aeroplane will fly fine with a huge balance point range, but even I would move it back from the off and I generally fly more nose heavy than most. The manual 220mm point was a safe forward position. Elevator power is not a issue like it can be on Bandits, rotation and flare will be fine.

i use 2x 2200 li-po packs and it's good for 12-15 flights. The 1800 will be fine, also the stock 2100 3s li-fe does 3-4 flights with the P-140 Rxi.



Dave
Old 10-05-2014, 03:16 PM
  #4439  
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Thanks guys. Btys are at the pockets. I'm carrying extra gear which is the issue. Gyro PB. Display.turbine disp. etc. I'm also running futaba bls157 servos and powerbox powerbus..SMK pump...4 tanks. Very much overkill on gear....I'll try the 1800s and get a smaller turbine bty. Changing btys is easy and I usually do every 3 flights. I'm also carrying a 400ma bty for electric brakes. I only have the gear air tank and the GPS sensor in nose but the powerbox is fairly forward..... I'll try Dave's idea with btys. I have 4 x1800ma 2s btys I can use. Should put me on 220 by my test the other day... In a hurry to fly as we are heading to the hot season here when they won't let us fly turbines for fear of grass fires etc...hence my anxious nature here..otherwise it waits to next year or one of our rare Tarmac open days. Thanks again.
Old 10-05-2014, 03:41 PM
  #4440  
Ruizmilton
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A friend used the 220mm CG and crashed on landing everytime he flew (yes, had several repairs on his UF) on every flight the right wing would drop when he tried to flare, once he moved the CG towards 230mm, the problems stopped, I have flown mine at 235mm since the maiden, have never had an issue on landing, all landings almost perfect, and I'm really bad at landing...
Old 10-05-2014, 03:48 PM
  #4441  
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oucch!!!. maybe I add some tail weight... never use weight but there is always a first time. sorry to hear of your bad experience.....just ordered 2100 btys for turbine ...
Old 10-07-2014, 01:44 AM
  #4442  
Dave Wilshere
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I've flown lots of UF at 220mm and its never been a problem, maybe the air is thin there?

Another BA UF being collected today, this one P-140Rxi again. Popular scheme now!

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Old 10-07-2014, 02:53 AM
  #4443  
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Dave. In the manual it suggests a flap to elevator mix for takeoff and landing. "The Ultra Flash requires down elevator with flap. Take off 1.5mm and Landing 4.5-5mm measured at the elevator trailing edge tip. Exact figures will be affected by balance position."

Is is this the case? I had missed this but it makes sense of course. Just doing double checks before maiden in two weeks
Old 10-07-2014, 08:16 AM
  #4444  
Dave Wilshere
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Oh yes! Really needs it.
Looks a lot, but losing the drag brake blade from the top of the flap as on the Classic Flash changed the whole set up

Dave
Old 10-11-2014, 12:43 PM
  #4445  
scoeroo
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Originally Posted by Dave Wilshere
Oh yes! Really needs it.
Looks a lot, but losing the drag brake blade from the top of the flap as on the Classic Flash changed the whole set up

Dave
Dave W

What did you find the best CG for the classic flash ?
Old 10-11-2014, 02:12 PM
  #4446  
Dave Wilshere
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The 365mm is my figure and the instruction manual aeroplane is still flying at that, 8 years later!

Dave
Old 10-11-2014, 03:04 PM
  #4447  
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My UF had 140 flights on it when I bought it. Today I put my 110th flight on it and it's still as solid as it ever was. When you consider the performance this aircraft has and the sheer abuse it's had to take as my first turbine aircraft flying off a rough grass field, you realize what a truly amazing aircraft it is. Amazing!

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Old 10-15-2014, 06:14 AM
  #4448  
raron455
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I have upgraded my tanks to the Kevlar units,, SO
IF anyone needs a factory fuselage tank, I have one, I am not going to use it, I will give it to the first person who wants it,, All you gotta do is pay the actual shipping,, sorry fellas but I don't want to send it out of the US,, it is a real hassle..
Pm me, or email me if you want it,, My email is [email protected]
Old 10-15-2014, 06:59 AM
  #4449  
izzy
 
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I'll take it if still have it
shipping to Albany nY
tha ks
izzy
"I have upgraded my tanks to the Kevlar units,, SO
IF anyone needs a factory fuselage tank, I have one, I am not going to use it, I will give it to the first person who wants it,, All you gotta do is pay the actual shipping,, sorry fellas but I don't want to send it out of the US,, it is a real hassle..
Pm me, or email me if you want it,, My email is [email protected]"
Old 10-15-2014, 08:56 AM
  #4450  
raron455
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IZZY , you were first,, PM or email me the exact shipping address, then Give me a day or two, Ill get it boxed up, and ship it to you and I will let you know what they charged me

Originally Posted by izzy
I'll take it if still have it
shipping to Albany nY
tha ks
izzy
"I have upgraded my tanks to the Kevlar units,, SO
IF anyone needs a factory fuselage tank, I have one, I am not going to use it, I will give it to the first person who wants it,, All you gotta do is pay the actual shipping,, sorry fellas but I don't want to send it out of the US,, it is a real hassle..
Pm me, or email me if you want it,, My email is [email protected]"

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