Skunkwrks

I have one in my Pro, you will have to grind the former inside the fuselage as the tank is larger in diameter than the stock.
These adjustments have to be done, and by aligning the upper support to the former, I had to redrill holes for blind nuts as the original were now too close to the new diameter of the former.
Go slow as it takes time and i had to trim the fibreglass where the canopy sits to allow the tank access to the fuse.
It's a great tank
When you glue the back brace onto the tank, you will never be able to remove the tank as there isn't enough room on the former to clear it

Skunkwrks

Okay, then if you were too fast the you could have gone around you had a lot of fuel. it does land more slowly that an Ultraflash Evo or even a F18.
Maybe your CG was off, or did you use a Gyro, would have helped on that landing..............

essyou35

My Feedback: (11)

a gyro would have had no effect. It's oK I banged it up you feel superior whatever. I'm not a fan of this jet it happens.
20mph winds is going to be like landing a 3d plane. It's a challenge in a different way.

essyou35

My Feedback: (11)

So got my 2nd flight in today and chocked up more damage. This time 0 wind. I was trying out the slow flying characteristics and doing a bunch of diving. Four minutes in I got a flameout. I was barely moving so I did a 180 and landed in the grass gear up. Darn this slid on its belling 100 yards I was shocked. Ended up in the cut corn field and I had a little leading edge damage. Amazingly it was very little.

I noticed about 4 inch bubble of air in the fuel line and about 10% air in the UAT.

So here is an issue I am curious about, I put my pump in prime mode and ran it up pretty high. I took the jet and rotated it about, and I noticed a couple things. When the jet is nose down, fuel will poor out of the vent since the vent is on the front of the tank and all the fuel rushes there. Also the clunk is unable to get fuel with the tank half full in a dive. So when the jet is diving, it fuel really just pouring out of it? Also how to resolve the clunk issue?

I assume this would be an issue with other jets but maybe because this one dives so slow its a bigger issue? Any advice, seems once the tank gets to 50% time to stop diving?

Good news is I need to paint the leading edges AND the nose now, so I can just black and it will all match. This jets scheme needs a few more details anyways.

paulhat

I'm guessing that the only solution would be to use a air trap that is tolerant to a good amount of air gap.
10% isn't that much air. You should have got away with that. Maybe there is an issue somewhere else ?

jvaliensi

My Feedback: (1)

When the pump is operating air is drawn in thru the vent, so fuel cannot come out of the vent line.
Perhaps your clunk is coming out of the fuel in long dives. Tank baffles would help.
How about using a larger header tank?

essyou35

My Feedback: (11)

I'm using a 175ml intairco. I'm going to let the motor run it dry to prove it works. I read the paper gaskets aren't good. I'm kinda wondering if I need a 2nd vent and got cavitation? I was at 3/4 throttle for like 60 seconds while testing flaps.

essyou35

My Feedback: (11)

Here is where my uat starts sucking air when upright. I thought as long as it was touching fuel it doesn't suck air?

chevronflyer

My Feedback: (9)

that’s way more than 10%. Looks like 50%!air to me.

if your getting that much air in your trap you have a plumbing problem somewhere.

I have stopped using these fancy traps and have gone back to the bvm sock filter trap. After seeing bvm’s video that proves it can be 3/4 full of air and still provide fuel to the turbine

essyou35

My Feedback: (11)

Lol thats not from my flight, that is from my test to ensure the UAT is working ok. It flamed out at 50% air. The actual flight I should have taken a pic but it wasnt enough air to concern me. But it had a solid bubble going across the top of the UAT Id say 1/2" at most deep. May have been 1/4" It wasnt enough that I would could say that was the issue. Ill have to do my test with nose down. Im going to try another vent and replumb every thing. Hate fuel problems! This is my first flameout ever in 12-13 years. I test my sytems thouroughly!

BTW when I tests, I put the pump PW where it would be at WOT and put the nose down, it still spilled fuel out the vent.

Dansy

My Feedback: (53)

I used only Intairco iTrap and I have never seen the fuel level going that low, while doing high maneuver with lots of down time……you have a photo of the front…..?

I know they sell the glass that can be replaced….was that the case or purchased new?

Skunkwrks

A firm believer in having the Map tank at 45 degrees to allow air from being sucked into the inlet.
Those horizontal Jewelry looking tanks are more prone to more air allowing the pump to cavitate and flame out.
Not saying that a 45-degree map cant get some air into them they still do .

essyou35

My Feedback: (11)

So another thing I am thinking. I am using the CMJJets tank and as we know there are no baffles. However, they put a brass tube between the clunk and the outlet. I understand this is done so the long clunk line wont tangle, but its usually done so the clunk cant flip to the front of the tank and get stuck. And that is what it keeps the clunk from doing....

Given this tank is a big cylinder, Im wonder if I only need an inch or so of brass tube instead of the 6 inches they got there. This will allow the clunk to fall into the forward portion of the tank in a dive and say in the fuel.

Im thinking this could be ok mainly because this tank while a cylinder, is basically a big cube of equal dimensions. Thoughts?

essyou35

My Feedback: (11)

Wanted to add this here as well, I got a dent/crack on my leading edge of my wing. To fix it I cut a small access hatch on the bottom of the wing. I literally used a not new exacto knife and it cut it like butter. I had to do this on my other jets too and I always needed a dremel cutoff wheel. The exacto is nice as there is no material loss, but this jet is literally a big foamy. And its kicking my butt. I think it hates me.

khedge

My Feedback: (11)

essyou35,

sorry to hear about your fuel issues. For your tank i would highly recommend removing the brass tubing you have in your tank. My good friend Wayne Matthews has jet blog which i will link below. In my 2m rebel i use viton tubing and digitech ultimate fuel clunk that is heavy. My clunk can bend all the way to the front of my 4l tank in my rebel. This will alow the clunk to remain in fuel even in dives. This setup has been working flawlessly in my rebel for over a 100 flights. For your vent line i would do spool of fuel tubing circled around the tank so the fuel can not leak out of the vent as the position of the jet changes during flight.

here is the link to Waynes blog below:
https://www.sewbusy.com/jet-aerobatics-blog.html

v/r

Karl

sewbusy

I hope to answer some of your queries regarding your fuel situation. I refrained from answering, initially, because on a previous answer in a different thread, I was "taken to task." However, I DO think it is important to look at various ways to solve your issue. The "age old" method of using the brass tube in the pick-up line is to prevent the clunk from being trapped in a forward position. That will work for tanks that have that disposition.

However, the tank that you (and I) have, gives you a much less chance of the clunk being trapped forward, being a rounded one (tank), hence, I would suggest you looking into using viton fuel tube on your clunk from McMaster Carr and not using a brass tube at all. It also depends on the type of clunk that you use. I use the digitech clunk of which I will place photos below.

I fly F3S Jet Aerobatics and in our sequences, we have many up and down lines with pull or push out to horizontal flight from vertical flight. So it is important for me to be fully confident that I won't be "sucking air" with a trapped clunk. I know I will have input from some jet pilots regarding my suggestions, BUT, how many actually fly competition, is what should be the important question?

Now, on your fuel leaking out through the vent line..... Some say that because the fuel pump is sucking fuel, there won't be fuel leakage through the vent. That may be so, on a horizontal flight path whit the throttle up....however, on a down line, the turbine is at idle (or supposed to be) and there will be seepage when you pull out from the down line to horizontal. I judged at the 2018 Red Flag Jet Competition event and saw many jets doing just that, and I decided that I would bring over my 29 years experience of competing in a different discipline (Scale Aerobatics) and use some of what I learned. It is a simple fix and was also used by Andrew Jesky in his Leonardo. Most jet pilots run the vent line straight down the the outlet on the floor of the fuselage. I coil the vent (8mm). tubing) twice on top of the tank and that will solve your issue. I hope some will at LEAST try it before pooh Hooing it. You may be surprised!
Wayne

sewbusy

This will give you an idea of how F3S jet pilots fly..... This is in a heavy crosswind.

Skunkwrks

Wayne great advice from a pilot who flew a lot of Imac .
If we take out the brass line in the middle to allow the tubing to bend forward and back plus use a felt pickup or Digitech pick this will help eliminate a lot of air in the trap.
I have also encountered similar issues with more air in the trap when using the CMjet's six-litre tank.
I will switch out the heavy pickup and use an 8mm felt pickup to resolve the issue with mine.

sewbusy

Those changes will definitely make a difference. These two photos are actual before/after an 8 minute F3S practice flight with the equipment as mentioned in my previous post. Nothing has been "doctored" to portray a better result...this is just what I experience. I also land with approximately 1/4 tank left on the Leonardo.....AND, the Leonardo's tank was not round like the Rebel Pro tank, so I expect it to be just as good on the Rebel.
I would definitely like to know your results.
Wayne

BEFORE

AFTER the same 8 minute flight

BarracudaHockey

My Feedback: (11)

Great advice Wayne! Not every technique works for every installation and application, people need to keep an open mind.

Skunkwrks

With my six-litre CMjet tank with the heavy pickup and brass tubing in the middle, my trap tank had about twice as much air as your UAP tank.
I using the largest filter Carlos has, 22 mm felt pickup filter, plus I will remove the tubing.
When Carlos built my tank I asked him to use Viton tubing so these improvements it will certainly reduce the amount of air in my Map tank.
I can fly for 9.5 minutes and still have 1/4 to a1/3 tank of fuel left after landing amazing how when flying sequences and using the throttle you can save on fuel consumption.

Skunkwrks

khedge

My Feedback: (11)

I really like that cayman scheme on your rebel pro. Oh yes you can save a lot of fuel with throttle management. I am able to fly well over 10min (1/2 to 1/3 tank left (4L tank)) with my Rebel classic with the X180 i have in it. I stay around half throttle most of the flight and only go to about 3/4 for some of the upline maneuvers in F3S sequence. I use the same setup as Wayne with a smaller 100ml digitech UAT.

sewbusy

Very nice! I will check you when I'm ready regarding the throws you presently have on all the surfaces, including flaps. Most of the times, a manufacturer's recommendation is not what we normally end up flying with and since you have the Pro version, I will need your input when the time comes.
Wayne

Skunkwrks

Thanks, Mike McConville, a CARF rep here for North America showed me a photo of a Rebel Pro in this scheme, and I loved it.
I'm flying at 2/3 throttle most of the time with lots of power available for the uplines. My Map is four oz or 113ml and does the trick with high-flow fittings.
Next year I'm going to guess my flight will be ten minutes are i which out my pickup for a felt one.