New to turbines

[Figure9]

Well, after many years I've got myself a turbine.Wren44 heli, latest and greatest kero start. Glad I joined this forum as many of my questions are answered reading other post. I will be converting a Trex 800 with a Revolution kit. One thing regarding hopper tank, if I never plan to flip, roll or even stall turn my model, is the UAT absolutely necessary? Just asking because the Revo conversion kit leaves very little room for anything to be mounted.
Thanks, T

[Skiddz]

*Any* tiny air bubble in the line could interrupt the flow of fuel to the engine and extinguish the fireball inside causing a flameout. IMO, it's cheap insurance and probably best to figure out a way to get an air trap into the airframe.

I have the BVM unit in my Bergen and it'll suck the tanks dry and leave about 3/8" of fuel in the air trap before it flames out. I've never had a flameout in the air and I do fly aerobatics.

[cbergen]

Have you considered the gearing needed to swing the 800mm blades?

[Figure9]

No sir, I was going to use the stock 8:1 ratio to start. They are 780mm blades. What would you suggest?

[cbergen]

What RPM do you want to spin those blades at? 1450-1650?

[Figure9]

maybe 1500,1600,1700 for the high? I had these blades on a electric and spent most of the time at 1600.

[cbergen]

Well, doing the math, I like the 8.1 ratio for those RPM's.

At 1600 rpm, the gearbox will be at 12960, right at the peak power according to Wren's graph in the manual. Should work great!!

My reason for asking wasn't to be nosy, many use the stock ratio's for RPMs that don't allow the engine to produce the power and torque that it's capable of. For instance, running 700 sized blades at 2000 rpm puts the gearbox at 16200, which is way past the peak power. Better to change the ratio to 6.43 or 6.92 to bring the gearbox rpm down, saving wear on the gearbox AND, in my experience, saving fuel.

[Figure9]

Question, I'm using HV servos with a 2s lipo plugged directly into my receiver. Is this ok for the ECU? Just asking....

[Kiba]

Originally Posted by Figure9

Question, I'm using HV servos with a 2s lipo plugged directly into my receiver. Is this ok for the ECU? Just asking....

No problems supplying 8.4V to the FADEC through the RX/throttle cable when the RX lipo is fully charged, Gaspar has said the V10 FADEC will support up to 10V on the throttle port.

[Figure9]

Thank you

[Figure9]

Anyone using the PC cable for the XICOY ECU with success? Can't get a good connection, just all kinds of data and symbols flashing. Windows 8??

[Kiba]

It's kind of a picky setup IMO.

The most reliable way I've found is as follows:

1. connect the USB cable to your PC and the data port on the FADEC
2. check the "power from USB" box in the FADEC software
3. connect the RX battery but do NOT connect the FADEC battery.

If I don't do things in this order or try it another way I usually only see all the oddball symbols in the software.

[GLimo]

Do all this in this order and wait too for the Parameter download to complete. (The small progress prompt next to the "power from USB" Check Box).

DG

[Kiba]

Originally Posted by GLimo

Do all this in this order and wait too for the Parameter download to complete. (The small progress prompt next to the "power from USB" Check Box).

DG

Yep, forgot to mention waiting for the status bar to get to complete at 100% before hitting one of the two download buttons. It takes 30 seconds or so after applying power.

[Figure9]

I had done some searching on all the forums and found someone said that same order. It works every time if I do it in that order.