Dave Wilshere

It’s all down to the filling. I started using MAP traps because I could mount them flat in installations where space did not allow an angled install. The BVM bag seems to occasionally release an air bubble if it was mounted flat I guess because of the fan tail bag pick up.
Always filling a new instal I elevate the fuselage to get the tank feed fitting nipple to sit at the highest point (some MAP traps have the fitting on the top anyway), so all the air leaves the bubble trap bottle as I fill it. I also slow down the pump to slowly fill the bottle first time. I use felt clunks in main tanks throughout, so I land with practically no air in the bubble trap every time. That makes it rare I have to do anything more than rock the airframe or pulse the fuel supply to completely purge the bubble trap of air.

As said the whole point of a bubble trap is the air is around the edge, pickup in the centre.

N4S

Guys, my apologies for asking too many rudimentary questions. I have been flying PNP jets and my build skills are not that good. I am trying to figure out how to install the aileron servos. I see the wooden brackets in the parts bag, but not sure how they get assembled and installed. A picture of the installed servo would be greatly appreciated!

I'm also not sure what the bigger piece of plywood with 4 square cuts is for. That was in the UAT bag.

Dave Wilshere

Yes, cut them out, assemble and fix to plate. Plate will need rough over with 80 grit and alcohol. Look at something like a Viper manual on CARF’s site.

other plate is for CARF hopper tank…scrap wood for the box😉

N4S

Dave, you are a lifesaver! Thank you! The Viper manual has detail explanations and pictures for servo mounts. I copied a picture of the mount here, maybe it helps the next guy.

dubd

I just ordered a CARF Rebel Classic and looking for an engine. Leaning towards a Kingtech 142. Any reason to consider a 120 for this plane? Will be flying out of a small field.

Desertlakesflying

My Feedback: (28)

I used Hysol to do my servo holders. 300 flights in with no issues.

LA jetguy

I have a brand new in he box never used Jet Central lynx (130N) excellent price .. if interested PM me

David

Dave Wilshere

All of ours have JetCat 130Rx turbines (Actually over 150N thrust) these are a great combo, but anything over 120N in the small light case turbines will fly it nicely

Dave

Viper1GJ

My Feedback: (20)

N4S,
It's great you are asking questions. I'm really glad your reaching out for help and ideas on these jet forums. I've been doing RC for 56 years and turbines for 21 years and I still routinely ask for advice and answers here. Never a dumb question! Guys have caught my mistakes just from photos I posted. Any problem has usually been faced by someone before and this is a great place to get advice. Great job asking. Best wishes on your build, and keep on asking!
Gary

dubd

Thanks, Dave. That’s helpful.

jvaliensi

My Feedback: (1)

My Rebel is complete except for the radio programming and final CG check.
The empty weight is 10.5kg (23.1lbs).
How does this compare to what others get?
I believe the stock tank is 3.6l + 4oz UAT which is about 3kg of fuel. With the P130 (150N) It should be better than 1:1 thrust/weight.

Agrav8ed

Sounds about right. I have a Swiwin 140n and my auw is 23.36 pounds.
Tone

Dave Wilshere

Kg….I so hope not 😉

Dave Wilshere

Little and large out yesterday.

Agrav8ed

Lmao. Good catch Dave. I corrected the post. It should have said pounds.
Tone

jvaliensi

My Feedback: (1)

Hi,
I checked my CG with no fuel. The Xicoy indicated tail heavy and I needed 150g in the nose.
Then I filled the UAT and added about 1/8 tank fuel. Rechecked the CG and now I'm 350g nose heavy.
How much does the CG shift between full fuel and empty? Seems like a lot.
My batteries weigh 400g and are in front of the front bulkhead. If I pull them out with an empty tank the airplane sits on its tail.
What is is good CG spot to start with?
Thx

Dave Wilshere

Throw you electronic balancer in the trash. Fill the main tank 1/3rd full. Pick the assembled model up with fingers under the opening lip inline with the back of the wing spar. No weight in any of the 4 I have flown three batteries in the nose area. Go and fly…

jvaliensi

My Feedback: (1)

Simple and practical advice. Thank you
(I do enjoy using my Xicoy device though)

Dave Wilshere

I understand liking the technology, there are just too many variables with these units.

jvaliensi

My Feedback: (1)

It turns out I had one sensor unplugged and it was giving me a wrong reading.
The CG is spot on with 1/3 tank of fuel.
Always double check...

jvaliensi

My Feedback: (1)

I like to see how others install the equipment in the airplanes, so I'm sharing mine.

Dave Wilshere

When you run the turbine, ensure you release the filter from the clips at idle and ‘flick/knock’ the the filter to clear bubbles. Then again at full power. Have you checked the filter cap is still tight after assembling the filter?

Dave

jvaliensi

My Feedback: (1)

Will do!

Bob_B

My Feedback: (11)

I always let the filter float on the tubing.
I also thought Jetcat recommended a vertical orientation of the filter?

Dave Wilshere

They do, but actually that is all about filling it. I either tip my model while filling a new fuel system, both to purge the hopper tank completely of air and when I prime the fuel filter first time. If the filter is vertical all the air goes. Actually a lot of my installations have enough tube so I can unclip the filter and rotate it vertical just while I prime/fill it.
In flight the filter is every angle possible, so I never worry, the filter gets mounted at whatever angle suits the install set up, or sometimes no clips if that works out best.