Official Freewing B-2 Spirit Bomber 86" Twin 70mm EDF Jet

[RudyD54]

Hugh Wiedman

All this power talk got me curious. I just hooked mine up to a freshly charged SMC 5300 and my meter peaked at 121 and settled in around 116 amps at full throttle. We shall see on Monday if that’s enough to get off the grass.

[Radar-Guy]

…
I'll get a power draw reading on Monday of the stock B2 fans with an SMC 5300 and let you know what we're getting as we're about to find out if it will get off our grass runway.

Thanks, Hugh! Looking forward to it. Perhaps my charger gives different results than your measuring device. I‘ve got quite some Lipos here and these are well maintained, but I don‘t recall any of these showing values you mentioned. Bad cells usually show a value of > 8. But that should be discussed in depth somewhere else.

What do you think about this excerpt from the manual?

[Radar-Guy]

Radar-Guy I saw you are using 50mm for the front, what retract and wheel size are you using for the mains?

https://www.hobbysquawk.com/forum/rc-airplanes/rc-military-jets/341524-official-freewing-b-2-spirit-bomber-86-twin-70mm-edf-jet?p=342958#post342958

[Hugh Wiedman]

Thanks guys! The IR values were measured with a Junsi 4010 charger and my Lipos with such or lower value are powering my planes just fine. The outside temperature was considered as well, we had 20 deg C.
About the voltage: Who is using onboard telemetry or logging? You will NEVER get 4,2 V/cell under "standard EDF loads". It also of not much value to marvel at peak power, which was available for a few seconds. Have a look at performance charts published by serious EDF manufacturers like Wemotec or Ejets/Jetfan, where "stabilised" voltages during their testing was around 3,7V/cell. This is also the reason for the fantastic thrust values for fans from China. Power a fan unit with a steady 25,2V power supply and WOW!!!

I didn't fit a logger yesterday, just a real-time module. I will add one next time. Here is an example of a logged flight. Single FMS 70mm EDF, 6s, 3060-1900 kV, RT Lipo.
Red graph shows current, blue one Voltage

@ Hugh: Since you were involved in battery testing, could you show me one of your in-flight recordings? I'd love to replace my rubber bands!

I hear you, good point, although I will say that I won't use a battery with individual cell IR over 3. The SMC's are all in the 1.5-1.8 range and my "worst batteries" the HRB's/Roaring Tops/Admirals are in the 2-3 range (never use them anymore). I've not left the GT power meter hooked up in flight and yes, as the voltage drops, so does the Ah/Watts, as I've also tested them on the bench at 50% charge, but with a decent battery, it is not dropping down in the 90 Ah range. I'm no expert on EDF's, but I can tell you the the twin 70mm E-Flight fans EF2860-1850 Kv inrunners that came stock in the SU-30 were horrible fans and 1/2 the time I could not get it off grass. A fully charged 6000 still produced 120Ah and about 2800Watts, and at 50% charge it was 107 Ah 2400 Watts. I know the FW fans in the B2 are much better than those and top end your at 100 Ah and probably 2500 watts. The 70mm FMS fans together in the SU-30, 151 Ah/3700 watts, and at 50% charge 138 Ah/3100 watts. If you're only pulling 100Ah on a fully charged battery with those fans, somethings not right. Bench testing is one thing, only a place to start at. Since I fly off grass, the only real indicator is ground speed on take-off and there the bench testing has confirmed actual in-flight results.

I'll get a power draw reading on Monday of the stock B2 fans with an SMC 5300 and let you know what we're getting as we're about to find out if it will get off our grass runway.

[SanExup]

Radar-Guy I saw you are using 50mm for the front, what retract and wheel size are you using for the mains?

[Gilatrout]

Photo op at the field today.

[xviper]

Ready to fly. I think the only thing that could have been done or upgraded is the rudder rods. I had some issues and it took me a a while to set it up correctly. To solve this I would replace the rods with tie rod style rods and end. Just one end has to be reverse threaded and one end is reverse thread. Simply twist and off you go. The factory way is not bad but it gave of us some problems. Tested it on the road and it goes nice and straight during testing. Fast and slow. Looks like Sunday will be my day to test it.

I see what you're getting at ........................... "Turnbuckle" style. Good idea.

[MeyerVW]

Ready to fly. I think the only thing that could have been done or upgraded is the rudder rods. I had some issues and it took me a a while to set it up correctly. To solve this I would replace the rods with tie rod style rods and end. Just one end has to be reverse threaded and one end is reverse thread. Simply twist and off you go. The factory way is not bad but it gave of us some problems. Tested it on the road and it goes nice and straight during testing. Fast and slow. Looks like Sunday will be my day to test it.

[jasmith41]

On second thought, that doesn't seem right, or it's very low. Watts=Amps X Volts. So 2,520 Watts (that's both fans together, not each fan) = 100 Amps X 25.2 Volts (a single 6S Cell). 2,520 watts for 2 70mm fans is anemic. The 70mm FMS Fans I put in an SU-30 draw (together) 150.9 Ah and 3,750 watts using an SMC 6200. Using and Admiral or other battery more like 135 Ah and 3400 watts. At 90Ah, you're down to 2250 watts (for both fans together). I have rubber bands that work better!

Too much math...😆😎

[jasmith41]

I thought about that diagram myself but there's one potential anomaly ..................................... Notice how the gain (G) pin on the gyro is fed by the black (dark) wire of the 3 wire lead? Then it goes (single wire) to the "master gain" port at the RX. (The HE and E-52 gyro uses a 3-wire lead than ends in 3 separate single wires with their own plugs. A private individual would use a standard 3-wire to 3-wire female/female extension.) Those who have "polarity" on the brain will then plug that end with the single black wire to "ground", in which case, it WON'T work. That black lead must go to the "signal" pin on the RX port. Plus, on the B-2, if a person used a 3-wire lead, it may be necessary to either pull out the other two ends in the plug or clip the other two wires to prevent any signal interference because the RX will send power through the middle wire and the remaining wire is grounded.

They said there'd be no math...

[jasmith41]

I swear to God, if you guys keep posting all this sh*t about how great that plane is, I'll f*ck up again and go buy one without prior approval from the war department (wife)...😂😂😂

Just keep it up...

[jasmith41]

Yah, I think this one is a complete disaster and would be more than happy to relieve you of it for say a 50% discount, which is obviously well more than it is worth. Seriously, you haven't even unboxed it and you're listening to a few crazies instead of the designers and those that have been flying it for over a year and are raving about it? Finish it out, set it up as the those real experts tell you to and just have a blast with it and stop whining!

🤣🤣🤣🤣🤣😆😆😆😎 "and stop whining..."

Save the whining for the maiden if you don't set it up right...

[crxmanpat]

"Spirit of the Weeds"

[Radar-Guy]

Single wheel main gear conversion finished, the nose gear wheels were also exchanged (50mm). Reverting to stock main struts can be done in less than 10 minutes, no foam had to be cut at this point. Positive AoA is retained.

[Radar-Guy]

I would love if you posted those

Files are available here:

https://cults3d.com/de/modell-3d/verschiedene/freewing-b-2-control-surface-setup-tools

Note: the rudder setup tool is currently symmetrical in regard to up/down deflection. 22,5 mm per direction. During my setup, the "closed' position - the "TE" of both rudder surfaces - was 2-3 mm below the wing tip's TE. I've corrected this by adjusting both rudder surfaces by equal amounts to get both TEs level.

[xviper]

You only need to change one bit in a device ID to make them incompatible. So even if functionally equivalent the E52 may have been deliberately made incompatible. I don't know anything about the effect of power cycling.

For first flights I would not recommend messing with the gyro anyway.

That is true and indisputable.
See my post #574 for updated and corrected information.
I agree that the first flights should be with gyro as is, however, doesn't hurt to hook up the master gain and leave it at 100% to allow the set gains to do their thing. At least that way, if oscillation occurs, it can be reduced or turned off. I see no sense in increasing travel on the rotary to above 100% until the set gains can be altered.

[Radar-Guy]

Thanks guys! The IR values were measured with a Junsi 4010 charger and my Lipos with such or lower value are powering my planes just fine. The outside temperature was considered as well, we had 20 deg C.
About the voltage: Who is using onboard telemetry or logging? You will NEVER get 4,2 V/cell under "standard EDF loads". It also of not much value to marvel at peak power, which was available for a few seconds. Have a look at performance charts published by serious EDF manufacturers like Wemotec or Ejets/Jetfan, where "stabilised" voltages during their testing was around 3,7V/cell. This is also the reason for the fantastic thrust values for fans from China. Power a fan unit with a steady 25,2V power supply and WOW!!!

I didn't fit a logger yesterday, just a real-time module. I will add one next time. Here is an example of a logged flight. Single FMS 70mm EDF, 6s, 3060-1900 kV, RT Lipo.
Red graph shows current, blue one Voltage

@ Hugh: Since you were involved in battery testing, could you show me one of your in-flight recordings? I'd love to replace my rubber bands!

[kallend]

I supposed I should have used a different term, perhaps "average" or "inexperienced in gyro set up". We've already seen this on RC Guppy where a couple of people have hooked up the master gain and it didn't work and they spoke of "standard polarity".




The next thing coming down the pike is the use of the HE programmer on this E-52. Several have indicated that it did not work, however, one person made it work by unplugging the power and plugging the battery back in again. Now I'm beginning to wonder if updating the HE programmer would make it work every time. It would seem that the HE programmer needs an update to work well with the new A3S4.

You only need to change one bit in a device ID to make them incompatible. So even if functionally equivalent the E52 may have been deliberately made incompatible. I don't know anything about the effect of power cycling.

For first flights I would not recommend messing with the gyro anyway.

[xviper]

I'm a "private individual" and I had no problem connecting it up correctly, based on the diagram.

I supposed I should have used a different term, perhaps "average" or "inexperienced in gyro set up". We've already seen this on RC Guppy where a couple of people have hooked up the master gain and it didn't work and they spoke of "standard polarity".




The next thing coming down the pike is the use of the HE programmer on this E-52. Several have indicated that it did not work, however, one person made it work by unplugging the power and plugging the battery back in again. Now I'm beginning to wonder if updating the HE programmer would make it work every time. It would seem that the HE programmer needs an update to work well with the new A3S4.

[Hugh Wiedman]

Onboard telemetry (real time display on TX) showed peak value of slightly above 100 A.The Amp draw stabilised at around 90 A, no unusual sag of Voltage. That‘s close to 500W

On second thought, that doesn't seem right, or it's very low. Watts=Amps X Volts. So 2,520 Watts (that's both fans together, not each fan) = 100 Amps X 25.2 Volts (a single 6S Cell). 2,520 watts for 2 70mm fans is anemic. The 70mm FMS Fans I put in an SU-30 draw (together) 150.9 Ah and 3,750 watts using an SMC 6200. Using and Admiral or other battery more like 135 Ah and 3400 watts. At 90Ah, you're down to 2250 watts (for both fans together). I have rubber bands that work better!