C-ARF Ultra Flash build Thread + Video
#4301
Join Date: Jun 2008
Location: Hong Kong, HONG KONG
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Gents,
Have you ever felt the need to upgrade the fuel plumbing to larger diameters compared to the stock plumbing?
Secondly, for those using the Futaba 6014 rx with JR digital servos, do you run the RX in normal or highspeed mode?
Thanks.
L
Have you ever felt the need to upgrade the fuel plumbing to larger diameters compared to the stock plumbing?
Secondly, for those using the Futaba 6014 rx with JR digital servos, do you run the RX in normal or highspeed mode?
Thanks.
L
#4302
My Feedback: (3)
Time to add some of my experiences with my new Ultra Flash. Unfortunately it wasn't all pretty but it has a happy ending!
First day out having a great time but landing from the third flight my new Cheetah got hung up at a high idle - 60,000rpm. I am too new at turbines to recognize this! All I knew is it wouldn't slow down! I tried brakes but it swung sideways, all the while disappearing down a very long runway. I tried to hold it down with elevator and the brakes again but it bounced on the rough (abandoned airfield) runway. When it came down the pin in the right main snapped and it spun sideways off the tarmac. Hitting the crumbling edge sideways the nose gear pin snapped too! Dear Lord!
Well took her home and patched the wingtip. CARF touch up paints and some elbow grease got it looking new again. FYI "Superfil" from Aircraft Spruce And Specialties is the bomb! It says "Bondo For Airplanes" on the package and it is. My USA Carf Rep Andy Kane turned me on to that wonderful stuff. Key point: I also redid the flap linkage servo arm geometry to get 100mm of flaps. Before I only had about 75mm. This is a lot more drag. I am not using crow.
Second day out we all realized the Cheetah was getting stuck at 60'000 rpm in idle. Not all the time mind you but on the second flight of the day it did. Advice given was to kill it prior to landing but I wanted to know what was happening. So I got her down and stopped with some effort and we saw the high rpm. Normal would be 35,000. I called my Jet Central Rep and was advised to redo the setup, I redid it with some different Tx values and the third flight went great!
Well, starting up for a fourth flight I noticed my right elevator half was waving to me! After shutdown I saw that the elevator halves were not moving together. Something wrong with the servo? Back to the workshop! Not again!
Turns out the servo lead was smashed between the outer cool thrust tube and the top of the stab, it was shorting out against the tube... My fault I guess, I had simply run it across the top of the stab, taped in place with aluminum tape. So I rerouted a new servo lead internally. I dunno why I did it the way I did it first time around but beware! On my UF the cool tube presses hard enough against the stab that it dented it, and of course the servo lead got pinched there!
Well, the third day out was the charm. My UF flies well and I got to play with smoke for the first time in my modeling career. Did 6 flights total and couldn't be happier. Contractors Form Oil and, Powerbox pump, and a Tamjets tube put out a pretty awesome thick trail for this fast ship! Luck I still have it Now for a couple hundred uneventful flights, please, I have earned them!
First day out having a great time but landing from the third flight my new Cheetah got hung up at a high idle - 60,000rpm. I am too new at turbines to recognize this! All I knew is it wouldn't slow down! I tried brakes but it swung sideways, all the while disappearing down a very long runway. I tried to hold it down with elevator and the brakes again but it bounced on the rough (abandoned airfield) runway. When it came down the pin in the right main snapped and it spun sideways off the tarmac. Hitting the crumbling edge sideways the nose gear pin snapped too! Dear Lord!
Well took her home and patched the wingtip. CARF touch up paints and some elbow grease got it looking new again. FYI "Superfil" from Aircraft Spruce And Specialties is the bomb! It says "Bondo For Airplanes" on the package and it is. My USA Carf Rep Andy Kane turned me on to that wonderful stuff. Key point: I also redid the flap linkage servo arm geometry to get 100mm of flaps. Before I only had about 75mm. This is a lot more drag. I am not using crow.
Second day out we all realized the Cheetah was getting stuck at 60'000 rpm in idle. Not all the time mind you but on the second flight of the day it did. Advice given was to kill it prior to landing but I wanted to know what was happening. So I got her down and stopped with some effort and we saw the high rpm. Normal would be 35,000. I called my Jet Central Rep and was advised to redo the setup, I redid it with some different Tx values and the third flight went great!
Well, starting up for a fourth flight I noticed my right elevator half was waving to me! After shutdown I saw that the elevator halves were not moving together. Something wrong with the servo? Back to the workshop! Not again!
Turns out the servo lead was smashed between the outer cool thrust tube and the top of the stab, it was shorting out against the tube... My fault I guess, I had simply run it across the top of the stab, taped in place with aluminum tape. So I rerouted a new servo lead internally. I dunno why I did it the way I did it first time around but beware! On my UF the cool tube presses hard enough against the stab that it dented it, and of course the servo lead got pinched there!
Well, the third day out was the charm. My UF flies well and I got to play with smoke for the first time in my modeling career. Did 6 flights total and couldn't be happier. Contractors Form Oil and, Powerbox pump, and a Tamjets tube put out a pretty awesome thick trail for this fast ship! Luck I still have it Now for a couple hundred uneventful flights, please, I have earned them!
#4304
Thread Starter
L
No, the stock plumbing is fine-maybe the fuel clunk actually, latest kits have small hole felt inners either drill out to 2.7mm or change to one of our high flow units.
other than that we are running 180's with it
D
No, the stock plumbing is fine-maybe the fuel clunk actually, latest kits have small hole felt inners either drill out to 2.7mm or change to one of our high flow units.
other than that we are running 180's with it
D
#4305
My Feedback: (2)
Dave answered the first question. I'll answer the second. I have used the 6014 Rx with all JR digitalis and did not feel the need to run at high speed. Normal mode was very fast. This was on my classic flash. I'm building an UF which will have a Jeti Rx with JR 8411s all around.
#4307
Hi guy's, another flash hit the air for a maiden on Sunday.
Flew as expected , straight as an arrow
I think you'll be hard to find an easier building and better flying jet anywhere.
Thanking everyone and Dave W for there input in this thread which made the build and setup very easy.
Hardest part was getting through 170 pages just to make sure I had everything covered.
Here's some pic's
Cheers
Pete
Just one question, What's the best glue for the rudder linkage cover?
Flew as expected , straight as an arrow
I think you'll be hard to find an easier building and better flying jet anywhere.
Thanking everyone and Dave W for there input in this thread which made the build and setup very easy.
Hardest part was getting through 170 pages just to make sure I had everything covered.
Here's some pic's
Cheers
Pete
Just one question, What's the best glue for the rudder linkage cover?
#4310
Join Date: Jun 2008
Location: Hong Kong, HONG KONG
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Dave answered the first question. I'll answer the second. I have used the 6014 Rx with all JR digitalis and did not feel the need to run at high speed. Normal mode was very fast. This was on my classic flash. I'm building an UF which will have a Jeti Rx with JR 8411s all around.
#4312
Thread Starter
#4313
Join Date: Nov 2006
Location: Hamilton, ON, CANADA
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Dave
I know you always say the Ultra does not need crow but is there any adverse effects to having crow?
I have crow on my Ultra and I notice that when I slow it down with full flap and crow, it tends to really drop the nose in the turns. It then takes a lot of elevator to correct it. Straight and level it is fine.
I did not notice this on my classic flash. With the classic I could drag it around the sky nice and slow with full flap and crow.
I know you always say the Ultra does not need crow but is there any adverse effects to having crow?
I have crow on my Ultra and I notice that when I slow it down with full flap and crow, it tends to really drop the nose in the turns. It then takes a lot of elevator to correct it. Straight and level it is fine.
I did not notice this on my classic flash. With the classic I could drag it around the sky nice and slow with full flap and crow.
#4314
What you guys using to hold your batteries down and tight? I got commercial Velcro on the batteries and the side walls of the fuse but it's not secured to my taste just yet.
Just wanted to to know what everyone else is doing
Just wanted to to know what everyone else is doing
#4315
Thread Starter
Dave
I know you always say the Ultra does not need crow but is there any adverse effects to having crow?
I have crow on my Ultra and I notice that when I slow it down with full flap and crow, it tends to really drop the nose in the turns. It then takes a lot of elevator to correct it. Straight and level it is fine.
I did not notice this on my classic flash. With the classic I could drag it around the sky nice and slow with full flap and crow.
I know you always say the Ultra does not need crow but is there any adverse effects to having crow?
I have crow on my Ultra and I notice that when I slow it down with full flap and crow, it tends to really drop the nose in the turns. It then takes a lot of elevator to correct it. Straight and level it is fine.
I did not notice this on my classic flash. With the classic I could drag it around the sky nice and slow with full flap and crow.
There are two affects, changing the relative angle of attack between the root and tip and drag/lift reduction.
The Ultra Flash has much more flap than the Classic Flash, so I don't see the need for drag from crow and the affect I don't like that I have experience on all the UF models I have flown with crow is the sudden loss of lift if you hold it off.
Because we don't fly in them and have accurate instruments giving us speeds that test pilots have said are the magic numbers to do each important stage at it comes down to how the pilot controls the aeroplane and its landing phase. Ali gets on fine with crow and other pilots too, my group all don't use crow and again get on fine without it.
Dropping the nose in turns sounds more like nose heavy, unless you are flying it really slowly with lots of flap and crow...dragging it around. Most crow set ups use a lot less flap, so its still producing some lift. What flap angle do you have and what crow.
Hope that helps
Dave
#4316
Thread Starter
Dave
#4317
My Feedback: (7)
The use of crow has advantages and disadvantages IMO. I know DW doesn't agree but I can say without a doubt that it tamed my UF considerably with regard to low speed wing drop. This is not in question in the case of my UF - it is a plane fact. Because of this I will NOT fly my UF without crow. However, I don't like what it does to the flare phase of landing. Without crow I could grease my UF on pretty much every time. Now with crow for some reason I just can't get that perfect flare. As DW says, it tends to want to drop out on me and I wind up making landings more solid that I'd like.
#4318
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Join Date: Jul 2012
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Another UF to go up this Friday wish me luck a month turnaround since my classic broke up mid flight
thanks to some great friends and carf they got me up and flying in a month so here are some pics for you to rejoice on
thanks to some great friends and carf they got me up and flying in a month so here are some pics for you to rejoice on
#4322
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My first landing was horrible fractured the stab
after the main gear leg snapped and flew back then It slid down the runway on the wingtip
I fixed all the above and have about 20 great flights while I was practicing for my waiver got my waiver and flew the crap out of the flash
loved it and still do. At a rally I was doing a smoke pass went vertical to get it as light as possible for landing meaning running the saddle tanks dry as they are used for smoke
I then did a full speed pass from high alttitude and the plane dipped I pulled up and the left wing flew off and it went into a wild spin ending up with it on the ground in 3 big peices... Nothing was broken thank god just 2 stripped servos and the pilot having some brown in his pants lol sent the turbine back and servos to be checked all back and I'm ready for this Friday to maiden my amazing new Flash making it just 4 weeks from splash to blast
kurt
after the main gear leg snapped and flew back then It slid down the runway on the wingtip
I fixed all the above and have about 20 great flights while I was practicing for my waiver got my waiver and flew the crap out of the flash
loved it and still do. At a rally I was doing a smoke pass went vertical to get it as light as possible for landing meaning running the saddle tanks dry as they are used for smoke
I then did a full speed pass from high alttitude and the plane dipped I pulled up and the left wing flew off and it went into a wild spin ending up with it on the ground in 3 big peices... Nothing was broken thank god just 2 stripped servos and the pilot having some brown in his pants lol sent the turbine back and servos to be checked all back and I'm ready for this Friday to maiden my amazing new Flash making it just 4 weeks from splash to blast
kurt
#4325
My Feedback: (3)
Gotta admit I haven't used Crow yet in my jets. But in my gliders (slope racing and hotliners) it is the only way to get them down! One thing I know is I do not like the way my gliders handle with a lot of up aileron crow, it is for landing, I need the drag, period. In the jet community I see Crow is very popular but I am surprised by the great difference in the amounts used by different modelers. For some 5mm of Crow is about it, to me that sounds reasonable, the crow will modify the airfoil camber, act as washout, and force the outer wing to stall last, allowing the pilot positive aileron control at a slightly higher angle of attack to touchdown. Large amounts of Crow would appear to me to act more like spoilers. Like in my gliders. Now you are really killing the lift on the outboard wing and will be reducing aileron effectiveness. This is opposite of washout. So I do not know where the line is and probably won't do the testing to find out. But if I were to use some crow it would be to enhance aileron effectiveness and overall wing airfoil "forgiveness" and not purely for gobs of drag, I would use a small amount of crow, not "spoilers".
Last edited by husafreak; 08-08-2014 at 05:33 PM.