Planeprint Learjet 35

[davidk]

Michael's already done a full build on his so I'm just going to post some pics as I go along.  After a few Planeprint builds there's nothing surprising here... just well fitting parts and clever design choices.  Fuselage is done, landing gear in, added the passenger windows.  I think the cockpit window will be very thinly printed red and silver.

[davidk]

The EDFs and ESCs are in.  I'm using 2 FMS 70mm 6S 3060 1900Kv with 2 Aerostar 100A 8V BEC ESCs.  According to the Planeprint manual, and what I've previously read, I've disconnected one BEC by removing the RED wire from the Throttle cable.  I'm using a Y harness to power the 2 ESCs with 1 6S battery.

I've calibrated the EDFs together, at the same time.

At low throttle one EDF has more thrust than the other.  At about half throttle I can't really tell... the output is really strong... so I'm hoping things are ok.

[msatin]

Was it necessary to disable one the BEN'S, in order not overload the Rx? Or was there another reason?

[davidk]

Was it necessary to disable one the BEN'S, in order not overload the Rx? Or was there another reason?

Yes, that's right Mark.  Without disabling one BEC the Rx is receiving power from 2 sources.  I've seen planes fly without issue when 2 BECs are in use and no issues.  On any twin retail plane I've had one of the BEC's had been disabled... or... a separate BEC was used.  In the case of a separate BEC only 1 is used so why allow 2.

To test the system I swapped the ESCs and I also reinstalled the disabled BEC.  No change... one EDF is delivering more thrust at a lower level.  I recalibrated separately and then together and no change.  I don't think this will affect flight since at higher thrust levels I can't really tell if there's a difference.

[davidk]

The solution to the mis-matched EDFs was presented by Glenn.  Glenn had a new FMS 70mm EDF which he gave to me.  I tested it in my system and found that it matched the slightly lower thrust of one of my EDFs.  Glenn let me keep the matched EDF and I returned to him the higher thrust EDF.

Thanks Glenn!