Dave Wilshere

I do know a lad that flew at 240, but 232-235 lands like a feather

camss69

My Feedback: (46)

I’m going to pull the fuel out of the main tank and CG it and see where it’s at with UAT full and main tank empty. Where it was before which was 232ish with “landing fuel” which was 1/4 tank, was terrible.

Dave Wilshere

Balance sounds right…if that is where it was. You have the correct elevator compensation so at full Flap it’s trimmed at least level?(I like fractionally nose down )

essyou35

My Feedback: (11)

Rough day with the flash. Havent flown it for awhile. I added 1oz of lead on the elevator back by the tail cone. It seems to be a better CG but at slow flight it is very pitchy.
The first attempt I got too slow and it started stalling, the 2nd attempt was good but it is so pitchy I nearly nosed it in.
45% expo. Im going to raise it 50% and take out some down elevator. Im around 9.5" of CG.

Its like I need elevator high rates for takeoff and flight, and low rates for landing, seems backwards.

I got a bit of a flair there so I know the CG is getting better.

essyou35

My Feedback: (11)

Forgot here is the video to go with the above post!

KFX450

My Feedback: (30)

So it's been a while since I've flown a Flash. I've had this thing for over a year, and just had it finished last week. I forgot how nice these things are. Very precise. I have this cg'd at 230MM with just the UAT full. Flaps set up per the manual, I cut it back a little, no crow, and it lands really well. Inverted flight very little to no elevator. If the temps and humidity were not so insane around here, I would have stayed longer. But three flights were put on it.

Trying to attach videos here, but they are from an iPhone on my Mac. Says file not accepted, any idea how I go about this??

camss69

My Feedback: (46)

You can upload the videos to YouTube and then share the YouTube link here.

KFX450

My Feedback: (30)

Ok, Had to create a Youtube channel..Heres a link of it landing..

camss69

My Feedback: (46)

I’m replacing my loaner green stab with the new red stab. I’d like to make it so I can take the stab off and on without pulling the engine, fuel tank and pipe. Can someone give me an idea how to make the connections and heat protect the wire in that little space under the stab beside the pipe?

stormseq

Hi guys,

I have a rather strange request, just incase anyone is able to help.
I am looking for the box dimensions of the Ultra Flash Evo.

Hoping someone still has the original box around and can quickly measure for me.

many thanks,

J.Paul Saure

Hello RcUniverse!

It's been a long time without posting here.
I'm building my first jet, Ultraflash EVO with Kingtech 142 (30 years rc flying)

QUESTIONS:
1)
The tail cone piece seems a little long and the trust pipe fits a little loose inside it.
The cf cone is at the edge of the former..
Should I lay a ring of fiber glass on the inside of the cone to make the fit tight??
I already read here that I must trim the fg cone to the very edge of the stainless tube.
The distance between inner and outer tube seems correct from what I read, tube was assembled at the factory.

2)
The old manual shows two air inlet cuts on the bottom of the fuse. I read this thread and I saw some did it, but some not.
Should I just go with it?


Thanks for the help!


Saludos,
Jean Paul

acw

My Feedback: (1)

Hello Jean,

First, mount the pipe to the fuselage. Center it as much as possible in front. Then use a pen to mark the inside of the tail cone and remove material so it is flush. If it is a little loose, add some shims on top, below, left side and right side instead of adding a fiberglass ring. That way, you will have a little bit of air flowing.

As to your 2nd question. The first flashes had them, it appears to be optional on the EVO and, if I remember properly, the EVO user manual doesn't mention it. I don't have them on mine and have plenty of flights without any issue. Yet, this appears to be something CARF feels is necessary as, for example, the new Bolt has them... In my opinion, this isn't necessary when using a pipe with double tubes as the outside tube doesn't get very hot anyway.

Arnaud

Dave Wilshere

Non fully ducted that don’t have to have them.
They are on the Bolt to reduce fuselage temperature and for the same reason you can add them in the Evo

camss69

My Feedback: (46)

So yesterday we had 3 flashes at the field, 2 with 140’s with the full bypass and mine with the a 170 EVO no bypass. The full bypass planes were very noticeably faster than the EVO even with the bigger engine. We had a radar gun and not sure how accurate it is, but comparatively one of the full bypass 140’s was almost 50 mph faster than mine.

Dave Wilshere

There is 100% not that sort of difference between ducted and un ducted.
I have a friend with original ducted UF with a JetCat P-130 Rx (over 150N) that I’ve done a lot of formation flying with including competitions. We have had a few races with my JC P-130 Rx Evo and we can fly and turn together, we think maximum difference is less than 10 mph.

camss69

My Feedback: (46)

lol, well Dave, I don’t know what to tell you because both the radar gun and the eye test say different.

J.Paul Saure

Thanks, I will open the cooling holes.

I added 2 rings of fiberglass on the inside of the cone last night,
Now I fixed the pipe and trimmed the tail cone flush with the SS pipe, but I still have some play and gap.
The manual states the pipe should fit "snug" in the cone.

Video of the "play":
https://1drv.ms/v/s!AoQ1ND0zHb6Kg-dn...517Og?e=9jrtDO

Should I....
Leave it as is? How critical is the gap?
Add some more FG ring??
Shim with something else???

Thanks for your help!!



Saludos!!
Jean Paul

Dave Wilshere

Maybe its telling you something about your 170…

J.Paul Saure

Any thiughts about it?
Thanks!

wojtek

My Feedback: (73)

that is not really too much of a problem. you can stuff and glue a plywood shim on one side just to squeeze the pipe down a little more. there really is not much or any sideways load back there as the pipe is held into the aircraft at the front tabs .... and technically , a properly placed turbine, leaves the pipe without even that much thrust load on it either ..

stormseq

Hi,

Just wondering which gear set is preferred between the Electron or JP for the Evo?

I have a Rebel Hot with Electron, i find them trusty and they just work everytime and the breaks are awesome.

How are the JP gears? Anyone here used both JP and Electrons?
Are the JP gears lighter than Electrons?

acw

My Feedback: (1)

I have used several JPs and several Electron and now always buy Electron with a GS-200 controller moving forward. The Electron gear, in my opinion, are the best available. They are incredibly strong and well built. Maybe slightly heavier than JP but not by much. The only thing that is annoying with them is that they need loctite and some flat spots on the internal pins. Unfortunate that the factory doesn't do this for us. JP gears are OK too but I had my share of burned actuator and the gear controller (orange box) is a total piece of garbage. They will burn eventually and need to be replaced with a Xicoy gear controller.

Dave Wilshere

I use both, I have a Hot with over 300 flights, I had to free a nose drive thread after flying on wet grass for a weekend and then storing for a month. Lube and free and it’s back working, they have been flawless. **
My Evo thread starter has not had a single issue in operation, the retraction has been perfect **

My Electron gear have also been 100% reliable, but wheels can seize in wet weather use, fixed as in my RCJi article earlier this year.
Both JP and Electron have leg compression issues. JP on the larger sets main legs, they need 3/32” Tygon inside the spring as a bump stop to keep them open.
Electron need this on the nose leg, the Medium size nose leg is way too soft, a length of Tygon cures that too. ( Classic Rebel and Diablo need it too)

The difference is ** JP brakes are inconsistent, where Electron brakes are probably the best brakes overall made…ever

stormseq

Dave,
Thanks for such detailed reply, really appreciate this info.

thanks,
N

stormseq

Tank question.

About to lock on UF Evo, maybe with a fluorescent yellow/Orange Cayman scheme (Massive confusion)

I'll be opting for a K160.. What tank size is everyone using?
Is the stock Tank size of 3.5L enough for a 160 engine? If not then are the saddle tanks/wing tank absolute must for a 160N engine?

I won't be flying the entire flight full throttle.

Thanks again for all replies here