I'm sure it depends on the particular model, but how much flight time can you get from a .91 powered ducted fan model? How much fuel can it carry and where are the fuel tanks located?

Flight time
Hi! Jim, the question is are you using full throttle for the hold flight, how much fuel can it carry depend on how big is the model, the JMP T-33 is a large model, so it's fuel tank is bigger then the Y/A F-16, the location for the main fuel tank usually located in the C of G, bigger fuel tank mains longer flight time, bigger model mains it will fly slower, make your decision.

Raymond Ng

I'm planning a scratch built Skyburner and am trying to modify it to carry more fuel, just not sure how much fuel it needs. 10 min of flight with reserve fuel to cover a couple of go-arounds would be nice. This will require using more than one tank and a pump. What is a good way to connect several small tanks together so that the total fuel capacity can be used reliably?

Fuel tank manger

Hi! Jim, first the fuel go into the hopper tank, when it is full, it goes through a T-join and go into the main tanks, ( that's mains two fuel tanks that located close near the C of G point) and than when this two main tanks get full of glow fuel, it goes from this two fuel tanks to another two fuel tanks that is located may be about the C of G, because when you start the engine, you will using this two fuel tanks glow fuel first, a little bit nose heavy is acceptable when you takeoff, after a few minutes, when this two fuel tanks are empty, you will have the corrected C of G.

You don't have to worry the supply of the fuel, just put your back pressure from the pipe and fit it to the last two fuel tanks use the T-join, you will have enough fuel for the engine.

Jim,

I had a Skyburner XD-91 (the kit from Oldtimer Aircraft) that I flew this past summer (until it hit the runway at full speed.)

As designed, the Skyburner does not have enough width in the fuselage to fit saddle tanks. I ended up putting a 24 oz. Sullivan tank in the bottom of the nose section, just forward of the rearmost nose section former (where the inlets starts.) I carved away some of the large triangle pieces at the bottom to allow the tank to sit lower. I also velcro'd a 2 oz. hopper tank to the top of the main tank, situated to one side of the center line. You need the hopper tank with this setup, without it, after a couple of minutes of flight, any diving maneouver will allow the main tank clunk to pick up air. About five or so seconds later, the air reaches the carburator. Not good.

The fuel line ran from the pitot on the fan to the main tank vent,
from the main tank clunk to the hopper vent, from the hopper clunk to the remote needle valve, and from the remote needle valve to the engine carb. (Didn't need to mess around with tee's with that setup.) I also had a third fuel line in the hopper tank to fill and empty the system, the brass tubing for the fill line curved around to the bottom front of the hopper tank.

With that setup, I could get seven to eight minute flights with a good reserve for go arounds.

Yes, it does make for nose heavy take offs, but if you set up the landing gear so that the wings have a two to three degrees of positive angle of attack relative to the runway, it takes off quite nicely. You must balance the jet empty.

Something else you may want to consider. Separate flaps. I set my Skyburner up with them, and it sure slowed the landings down.

Have fun!
...jim