FB 1/7th F15 scale build
11-15-2015, 06:47 PM
#127
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Low rpm is a dead giveaway for no fuel. I'm still betting air bubble. Seen my share . Especially on a maiden. I ha two in a row on an L-39. Yeah diesel will smoke on shutdown but not enough to see in the air. My most recent looked like I had the smoke on. Was an rpm sensor that gave up. If the ecu commanded shut down,; no vapor trail. Flame out due to air bubble, fire goes out, pump still goes for a couple seconds until ecu sees rpm drop. Fuel in hot motor make vapor trail.
11-15-2015, 08:35 PM
#129
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Matt,
I think Kris is reacting to the high PW of 1000. That is extremely high and "usually" indicates a restriction of some kind, but since he says he didn't find anything in the fuel system, who knows...But something caused the PW to be abnormal.
I think Kris is reacting to the high PW of 1000. That is extremely high and "usually" indicates a restriction of some kind, but since he says he didn't find anything in the fuel system, who knows...But something caused the PW to be abnormal.
Last edited by George; 11-15-2015 at 09:09 PM. Reason: Fixed sentence
11-16-2015, 04:47 AM
#132
Matt pretty much like George said I am addressing the high PW. Eventually I plan on putting the K300 in this plane and I will need high flow anyway so might as well eliminate that part. I doubt my install caused the high PW but almost all flame outs that I have seen are caused by airframe fuel problems not the engine. When I help people trouble shoot flameouts they get pissed at me when I say its in the fuel system but more times then not I end up being right. So I need to at least follow my own advise lol.
When I do figure it out I will post what it was. Will be doing extensive ground testing before the next flight. I am thinking about 2 or 3 weeks from now.
11-16-2015, 07:01 AM
#134
Just wanted to post the takeoff video my son did with the F15 full of fuel and how it rotated. Some have said this plane wont rotate with the stock tanks and full fuel well this is proof. Also after draining the tanks I still had fuel center tank and half full saddle tanks. Probably looking at about a 15 min flight time on this plane with a 210 lol. Keeping this way because the K300 will need it.
https://www.youtube.com/watch?v=mJyH...ature=youtu.be
https://www.youtube.com/watch?v=mJyH...ature=youtu.be
11-16-2015, 12:24 PM
#137
Not to belabor it but I am still missing something. I get the high PW. I assume that means an unusually high pump voltage at full power.
Did the turbine quit at high throttle or did it quit when decelerating and the RPM undershot?
Or was it a typical white smoke, "air bubble in the fuel line" flame out?
Did the turbine quit at high throttle or did it quit when decelerating and the RPM undershot?
Or was it a typical white smoke, "air bubble in the fuel line" flame out?
11-16-2015, 01:04 PM
#138
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Just wanted to post the takeoff video my son did with the F15 full of fuel and how it rotated. Some have said this plane wont rotate with the stock tanks and full fuel well this is proof. Also after draining the tanks I still had fuel center tank and half full saddle tanks. Probably looking at about a 15 min flight time on this plane with a 210 lol. Keeping this way because the K300 will need it.
https://www.youtube.com/watch?v=mJyH...ature=youtu.be
https://www.youtube.com/watch?v=mJyH...ature=youtu.be
11-16-2015, 02:10 PM
#142
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I have seen several flame outs that were the result of collapsed UAT's or fuel lines because the draw was that hard on the line. That will create high PW and match symptoms you are saying. I am flying the exact plane and engine. I used hard 6 mm tubing and Tom Cooks aluminum UAT with big fittings. It is running perfectly
Glad you are making repairs. Best of luck with the remaiden
Glad you are making repairs. Best of luck with the remaiden
11-16-2015, 07:06 PM
#143
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11-17-2015, 04:03 AM
#146
Not to belabor it but I am still missing something. I get the high PW. I assume that means an unusually high pump voltage at full power.
Did the turbine quit at high throttle or did it quit when decelerating and the RPM undershot?
Or was it a typical white smoke, "air bubble in the fuel line" flame out?
Did the turbine quit at high throttle or did it quit when decelerating and the RPM undershot?
Or was it a typical white smoke, "air bubble in the fuel line" flame out?
Causes for low RPM are air bubbles fuel restriction or bad RPM sensor.
I was doing a low slow pass then at the end of the runway slammed full throttle and got the white smoke. Dont know what caused it yet. Will do further testing when I have it all back together hopefully later this week or next week. Late next week I plan on flying it again as long as it goes back together ok.
LowRP
Last edited by gunradd; 11-17-2015 at 04:07 AM.
11-17-2015, 11:02 AM
#147
Making progress. One of the hard to repair areas was going to be the nose bulkhead where it mounts to fuselage because the bolts pulled through and delaminated the plywood. So cut out the bad sections and made new ones. Then added a bigger piece behind the new pieces that the bolt will go through. Also been sanding and sanding soooo much fun.
