omaryafi

So my GPS reading is right, I clocked 610 km/hr, Evojet 180 inside.

paulhat

Was that at full throttle?

omaryafi

Yes at full throttle for a minute and a dive from almost 800m.

hotspot 01

190sv full throttle into a pass level flight 447 Kph.

setxws6

Be careful at reaching speeds of upper 200s and 300 mph. Lost my first UF this past summer due to right aileron flutter making a full throttle pass from a 1000ft. Right aileron de-laminated and the right wind folded at the fuselage and departed...I fly with a Rhino 36lb thrust. I was very fortunate not to loose everything inside and mostly lost just the airframe.

omaryafi

Structural failure? How many kgs servos you were using?

SECRET AGENT

My Feedback: (18)

Just curious, what difference can a servo make when delamimation begins? I would think once the structure delamimates nothing will stop the impending destruction.

omaryafi

the delamination definitely is caused by flutter at high speed, henceforth servo couldn't hold the load, so to know the capability of the servo can benefit all UF users.

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SECRET AGENT

My Feedback: (18)

How do you know that for sure?? You are making an assumption. The delamimation could have happened first and then caused the flutter. In that case (and it's impossile to know one way or the other) then no servo could have stopped the destruction.

Dave Wilshere

If it was de lamination it was before it left the ground or from flutter. Flutter will destroy any structure, in micro seconds.
If the wing/tail is stored incorrectly and the control horn is pushed on (or gear collapse or transport) the foam will tear, the hinge material is very wide, but the lifting will give control slop.
A diving full power UF can pick up speed really quickly, not a good idea, gyros don't always cope with a big speed differential either.

SECRET AGENT

My Feedback: (18)

I've seen leading edges delaminate in flight and the wing blow up. Quite spectacularly as well, Ha!

hotspot 01

It's a very rare pass at full throttle it's nearly 200 flights old all my leading edges are taped and fly at those speeds very gently. Most of my flying is taking advantage of the acceleration afforded by the bigger engine.

setxws6

What caused the flutter on my UF was the HD Dubro servo arms that were used. The flutter was bad enough to start striping the plastic teeth which caused even more flutter until failure. But this all happened in about 2 seconds or less. The servo was a JR 8411 which was actually still in working order and fine after the flutter and crash. I have new HD Dubro arms on my current UF that replaced the crashed one but don't push this UF as hard. I absolutely deliberately pushed it HARD on the pass that cause the crash. I thought it could go 300+ after watching the youtube vid were the guys went 300+ with a kingtech 210 on their UF. I have some nice SWB metal arms to replace the Dubro arms one day though.

Dave Wilshere

For some reason the JR dubro arms are a loose fit on the splines, they push on with almost no resistance. I won’t use them on high demand installations. The model was designed for the JR superservo HD arm and these stand up fine.

LA jetguy

Slightly tail,heavy... using a pair of 4400 mah in the pockets. Full by-pass, MKS HBL599 with aluminum arms and aluminum Clevis...

I have seen delamination occur only at the flap hinges... that was caused by a high speed full flap deployment. Now full flaps will not deploy above 100mph... Gyro gain is adjusted by speed to avoid oscillation... If built right and properly planned, this jet can be flown over 300 mph easily...

Now the challenge is to time how long I can keep the throttle pegged all the way...😀

David

hotspot 01

It always comes up with the goods surprising as it was never designed to have more then a 140.

wblombard

I was there to see the flight, Omar really pushes his UF. Insane actually. He pushes his models to some serious limits. Its very entertaining to watch. Mabrook my boy.

You should upload your UL video :-)

MaJ. Woody

My Feedback: (28)

I will never use the Dubro servo arms again. I lost my SM Hawk when the Dubro arm jumped splines on the servo and locked full over. My aggressor flash is using JR 8411 with the JR HD plastic horns. I really like those. My Fly Navy has Futaba 9156 with metal Futaba arms (actually so does the rudder on the aggressor).

essyou35

My Feedback: (11)

Anyone here ever flown or can compare to a JetLegend (now BVM) Viper Jet? The 1.9m version.
I've been flying one for like 6 years now first with a k100 and then a k140.
I fly from a 400 foot paved runway with death looming on all sides if you run off.
I never push it full throttle except in climbs and its not all that fast at 3/4 throttle. Probably 150 or so.

Im curious what I could expect to be different with a UF and why. My AUW is about 29 lbs.
First things I am wonder are the intakes are much smaller on the UF as is the canopy.

Considering getting the black and white UF as Im tired of the viper, which just happens after 1000 flights.

why_fly_high

My Feedback: (19)

I would like to credit my buddy Andy Arena for some cool pics of my Ultra Flash.

Dan Bierly

737Driver

That pic of it over the moon is awesome! "the Flash jumped over the moon..."

why_fly_high

My Feedback: (19)

Yes, we had fun playing with the moon. Lining up and timing with the 40% Decathlon was much easier.

Dave Wilshere

The main difference you have spotted, the natural drag of the UF is a lot less, so speed management is harder. You can't just shut the throttle and expect it to slow quickly, unless there is a head wind. Also the Viper tends to be heavy on the nose, so landings rarely bounce. The UF has perfect wheel positioning, so its light on the nose wheel and needs landing two wheel mains first.
Handling wise the UF is smooth and groovy, but the elevator is powerful with less stabiliser to cancel heavy handed inputs.

If you have 1000 flights and you have not broken it, my guess is your thumbs work fine ;-)

Dave Wilshere

So way back in 2015 this model arrived for me, too many other projects and life got in the way, but a miserable day here forced me to find all the parts spread around the warehouse. The fuselage is covered in dust and dead bugs!
It will be a stock build, Behotec C-36-2 gear, with Jet A1 legs and Intairco wheels, plus JR 8411 and 8421 servos. I'll use a spare P-120SX or 160SX I have.

Will see how free time goes around other projects, but should not take me long!

Dave Wilshere

Think I have found everything! It's amazing how things get spread around...one elevator servo cover took some serious searching!