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Old Sep 14, 2011, 11:05 AM
HAL... Open the damn doors!
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Originally Posted by sanman55 View Post
I would love to hear the fans if you could do that..it would show where the power is and what it takes to fly this bird...Both did an excellent job on the video..Great pilot and very nice video...good job..
Does it glide nicely now.??..after you did your trim settings...
Thanks for your insightful info...
sanford.
Glides like a butterfly! I'll re-render the video with no music and camera audio @ 100% instead of 85%...

Jack
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Old Sep 14, 2011, 12:29 PM
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By the way...

By the way, I'd rather be writing flight and crash reports instead of bitching around about the ESCs . It's just that I don't have the replacement ESCs yet and thus can only watch the MiG sitting on the shelf.

What I also did was organize me 2 Wemotecs with HET2W20, which are really nice at 4s. Maybe in a couple of weeks I can swap them in and we get some comparison numbers, e.g. on power consumption.

Cheers,
Henrik
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Old Sep 14, 2011, 12:42 PM
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Originally Posted by hklagges View Post
What I also did was organize me 2 Wemotecs with HET2W20, which are really nice at 4s. Maybe in a couple of weeks I can swap them in and we get some comparison numbers, e.g. on power consumption.

Cheers,
Henrik
I am curious if non-counter rotating fans will alter the 3d capabilities a noticeable amount
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Old Sep 14, 2011, 01:03 PM
HAL... Open the damn doors!
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Miramar, Florida
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Originally Posted by sanman55 View Post
I would love to hear the fans if you could do that..it would show where the power is and what it takes to fly this bird...
Ask and you shall receive...

Sebart Mig 29 (no music), Windows Media, High Definition, 124MB

Jack
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Old Sep 14, 2011, 01:24 PM
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Originally Posted by bsbauman View Post
I am curious if non-counter rotating fans will alter the 3d capabilities a noticeable amount
Me 2. But I don't think so, except for hovering. I mean, did you ever see much torque effect on the edfs you flew so far? I didn't...

One of the LX MiG builders, Brandonmoon, also ordered the new lander twin fans, which are a set of 2 counterrotating 70mm fans. So we should get some data on this, too. I considered them but they are rather heavy for a small plane.

Cheers,
Henrik
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Old Sep 14, 2011, 01:35 PM
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FANTASTIC... thanks so much for that.. its exactly what I wanted to hear.. Those slow flybys were Amazing.....IT was amazing how little throttle it took for her just flying around..and I see how it flew with no throttle on...Now if I could only fly one like that...
Seems to me that with the proper set up and pilot skills it does EXACTLY what it suppose to do...very few planes do what they advertise it can...This looks like it will be the most documented plane yet...Love it....

Thanks again....
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Old Sep 14, 2011, 01:38 PM
HAL... Open the damn doors!
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Originally Posted by sanman55 View Post
FANTASTIC... thanks so much for that.. its exactly what I wanted to hear.. Those slow flybys were Amazing.....IT was amazing how little throttle it took for her just flying around...Now if I could only fly one like that...

Thanks again....
BTW, the hand launch was not full power, more like 2/3...

Jack
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Old Sep 14, 2011, 01:47 PM
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Wow Was the gyro on during the hovers?? Can you give me a time stamp when it was a full power?? That way I can compair the sounds and know throttle positions.. Sorry for all the questions..I could watch the vid all day long
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Old Sep 14, 2011, 03:07 PM
HAL... Open the damn doors!
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Originally Posted by sanman55 View Post
Wow Was the gyro on during the hovers?? Can you give me a time stamp when it was a full power?? That way I can compair the sounds and know throttle positions.. Sorry for all the questions..I could watch the vid all day long
No gyro in the "Swifts" scheme we ordered, only the "Red Star" scheme so no gyro used at any point. Sounds like 1:44 is full throttle along with 2:22 and 2:39 into the flat spin. He might be near full for a few seconds after launch but he pulls back quickly. Quite a lot of that video was 1/2 or less, we put back 3,450 mAh (77%) in the 4,400 mAh pack we used. The flight time from the raw video was 4:06 from launch-to-hitting the runway...

Jack
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Old Sep 14, 2011, 03:39 PM
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Jack,
your vid makes me really getting excited for my weekend! Hope mine flies equally well (despite I definitely have less flying skills ) Great stuff!

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Originally Posted by hklagges View Post

I am a bit surprised about your conclusion. You have a plane that is specified with 2x45A ESCs = max 90A current. You already measured 103 to 112 A and expect even slightly higher currents. So you measured and now know that you are operating the plane outside the design envelope of its electronics. How can you conclude from your data that you don't have an issue? Your data strongly suggest that you will have an electronics failure in the near future, that should make you afraid. You have to ignore your data in order to come to your conclusion.

Cheers,
Henrik
Hi Henrik,
actually the 10+amps over the 45A/ESC spec in peak loads do not concern me. My static tests at Full power so far resulted not in critical overheating.
In flight, except maybe when hovering, I expect even lower currents. Detailed neasurements will follow.

I come from F5B flying, where 300-400A bursts on 200A factory-rated ESCs are not unusual.

Typically, there are 3 root causes for ESC failures (under the assumption the ESC is configured correctly for the motor, eg. frequency, timing, etc)
1. overheating due to high loads and bad cooling
2. partial throttle operation close to the max current limit over a longer period of time (time can be anything between <5sec in F5B or >1 min in an undersized F3A ESC)
3. too long cables between the battery and the ESC (the most underestimated issue)

Also Electronic components not within the defined manufacturing tolerances can be a problem, here obviously only the warranty helps.

1. can be addressed by placing the ESC in the airflow and to add cooling plates. This is well done in the Mig.
2. and 3. can be mitigated by adding additional LowRes capacitors. Thats what I did as precaution. As Jack's vid shows, this may have been an unnecessary action.

So if all this has been considered, it is usually no problem to exceed the spec.
Thats why I came to my conclusion and I look forward to flying it
Best
Stephan
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Old Sep 14, 2011, 05:17 PM
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Originally Posted by e_lm_70 View Post
EDF don't decrease much the AMPs on the air compared on static.

Actually some can even increase AMPs, since on the air at speed get more "air" in the EDF, so it can get even more work. Like a propeller with high pitch on air at speed increase the AMPs
I cant confirm this theory. My Spark EDF pulls ~120A static @11s during takeoff compared to < 80A in full speed horizontal flight (~160mph). When I dive at full throttle its even less.
In F5B models, where we fly props with up to 23" pitch, (what I would consider as "high pitch") current goes down significantly with the increase in speed - eg. 350A static @5s at launch down to ~160A at speeds around 150-170mph after 3-4 sec of acceleration.

Best Stephan
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Old Sep 14, 2011, 05:37 PM
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Proof would be in telemetry
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Old Sep 14, 2011, 06:47 PM
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Originally Posted by jfetter View Post
Glides like a butterfly! I'll re-render the video with no music and camera audio @ 100% instead of 85%...

Jack
Stinks,my windows will not play the vid,do you plan on putting on You-Tube ? and how in the heck did you got this jet to glide ? I went out today with about 15Deg down elev,the batt moved to the point it was way nose heavy,and the darn thing still just goes stright up when the throttle is pulled back.After watching the vid with Seba flying,he lands the plane under power-i fully understand why now...There is going to be a few people that distroy this plane on landing when that nose up hits them,and they are not ready for it.
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Old Sep 14, 2011, 06:51 PM
HAL... Open the damn doors!
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Miramar, Florida
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Originally Posted by VooDoo Child View Post
Stinks,my windows will not play the vid,do you plan on putting on You-Tube ? and how in the heck did you got this jet to glide ? I went out today with about 15Deg down elev,the batt moved to the point it was way nose heavy,and the darn thing still just goes stright up when the throttle is pulled back.After watching the vid with Seba flying,he lands the plane under power-i fully understand why now...There is going to be a few people that distroy this plane on landing when that nose up hits them,and they are not ready for it.
First, what does your Windows machine do, give me the message?

Second, you must not have read my tips did you? The plane needs to be trimmed properly, what looks like zero elevator is actually UP so when you glide and cut off power, it goes up. You can fix this by adjusting the sub trim on elevator (NOT the trim as this will change BOTH elevator AND vector nozzles!). Then when you power up and it likely dives, adjust the sub trim on Vector 1 and Vector 2 (aux 1 and Aux 2) UP to correct that diving under power (again, NOT the trim!)...

Jack
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Old Sep 14, 2011, 08:35 PM
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Originally Posted by jfetter View Post
First, what does your Windows machine do, give me the message?

Second, you must not have read my tips did you? The plane needs to be trimmed properly, what looks like zero elevator is actually UP so when you glide and cut off power, it goes up. You can fix this by adjusting the sub trim on elevator (NOT the trim as this will change BOTH elevator AND vector nozzles!). Then when you power up and it likely dives, adjust the sub trim on Vector 1 and Vector 2 (aux 1 and Aux 2) UP to correct that diving under power (again, NOT the trim!)...

Jack
I have never had a pitch down issue,only pitch up under power a bit,and very bad pitch up when the plane has no power (glide).I have adjusted the nossels for straight and level flight since.Yesterday it pitched up under glide and throttle application,so for my couple flights today i went out with the nossels down,elev down more (about 15 deg negative),and batt moved forward so the plane was nose heavy.It flew great under power,but as soon as i pulled off the power,it shot straight up (like another poster on this thread has talked about) I have to land under power,or i will get in big trouble.I will add more down elev for tomorrows flights,but that will be alot.Thanks a bunch for your time Jack,i appreciate your input.......I am just kind off banging my head against the wall at this time.All my other EDF,s got trimmed out perfect in a couple flights,i have 6 on this one,and am not even close in my eyes.
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