ORIGINAL: Roy Jimmy
OK.
Here are the way I was check the range. First only the battery pack and one servo connected in the receiver. Program this servo to a different position when entering fail safe mode. Turn on the radio and the antenna fully extended. The radio was place about 2 meters high. And free area between the TX and RX.
I was holding the Receiver, whip antenna and the servo in my hand. And was start walking (The was a lot of walking this weekend)
And I reach about 400-500 Meters (1160 feet) And still have a good signal I put the whip antenna on the ground nothing happened. I take the whip itself out of the connector, then and only then I got the fail safe. To me this look to be a good radio gear.
And so to the next test. The turbine , “ECU” and the ECU battery still in the airframe. Out side we have the receiver battery, the receiver and the wipe antenna. And the only connection is the throttle cable from the “ECU”. Make a start up, spool up the turbine got the green lamp flashing that show the full rpm. Is OK. Throttle back to idle. Take out the antenna on the TX. And start walking. The air frame are in a wood stand. After ca 180-200 meters (590-656 feet). Fail safe and the turbine shut down. Before this we was doing several testing with every thing in the airframe and every thing connected. With the turbine running I always get to the same spot 590-650 Feet and it shut down. After is shut down everything else working fine again. And this was the same thing I feel when I got this thing happened in the air, Fail safe no responding on the stick, after the shut down the control got back.
And look at the facts that I was using to different radio gear, also a different whip. I cannot see the problem are coming from here. Every battery pack is check out.
The only thing that have been the same all the way is the turbine and the “ECU”.
We also making a test with another jet with the same equipment in it. Let the turbine running on idle, take the TX and start walking the way I know very well after 1600 Feet we still not have any problem, I have to turn the TX off to get the airframe to get in fail safe. And the airframe was on the exact same spot as mine use to stand. This was a long story, but I think its been explain how we have performed this test.
Hi Roy,
I have seen some early design ECU / Pump combinations that emitted RFI all throughout all of the turbine components, actually emitting strong enough interference to shorten even the best radio's range, so it was useless. The cure was to Trap all of the RF being created by the poor ECU / Pump design with very a carefully designed RF shielding system.
Actually, a friend here in Denver produced such a devise he calls it the Rat Tarp. It works very well and was designed for the early Jet Cat turbine systems. Jet Cat has since solved its RFI problems several years ago. But I can tell you the Rat Trap is very effective.
Trapping stray RF emissions is not something the light of heart should try. Jerry found out if you don't totally shield & trap all turbine components, which includes all cables running to and from the turbine, proper grounding of all electrical wiring, batteries, valves, pump etc., etc. the RF gremlins just pop out somewhere else.
So Roy, from what you have told us your problem sounds like it is mostly centered around your turbine components, possibly one that has a slight short to your turbines battery wiring system. Find out if this is a known type of problem (SimJet), they may have a quick fix ready for you.
Note: The range check you described has some flaws, one being you shouldn't be carrying the Receiver or even be near the receiver antenna. Carry the transmitter and have a friend with a cell phone (cell phones don't seem to effect our RF links) or a good walkie-talkie for communication. Remember you can do the range check with the transmitter antenna removed the Baseline number you should achieve if you've got a good RF link is 300 feet. Anything less than 225 feet with means your transmitter / receiver link is not tuned properly.
Using the Rat Trap Jerry's and my range is slightly more than 300 feet turbine running at full power, or 1/2 mile ant. fully extended. Full power is the worst RFI condition. Actually the startup sequence is even worse in the autostart turbines, but as the startup sequence ends it then is full power or fuel pump running at high speed.
Good luck,
Lee H. DeMary
AMA 36099
See PIC of a Rat Trap installation in my BobCat the finished Blue anodized unit, and Jerry's proto-type in his Bandit.