I am beginning construction on the Great Planes Lear Jet 40 (.40-.45 glow) and am considering building it with twin EDF's.

Here are the specs (from Great Planes):
Wing span 55.5 in
Wing area 554 sq-in.
Weight 6.5-7.5 lbs
Wing loading 29 oz/sq-ft

I am looking for some shared expertise:

1) What size and RPM for the two EDF's would be required to fly this model? (Suggestions for EDF, RPM, ESC and LiPo?)

2) How will the weight vary between the glow engine/fuel tank versus the EDF/ESC/LiPo setup?

3) Will I need separate LiPo's for each EDF or will both run off one battery? (I know that separate ESC's and probably separate channels will be needed.)

4) I am consideringadding retracts and may also work in flaps. Any comments or suggestions?

5) Any building considerations and suggestions?

6) Would Ibe better off to scrape this idea and get a Wow foam Lear Jet?

Thank you very much for any and all responses. (I am just returning to R/C after a long absenceand am new to electric and to ducted fans.)</p>

This is very doable and sounds like a cool project! You need to ask this over in RCGgroups alot more electric people over there with alot more experience. You wouldnt need a very big set up. How big are the nacels? Inlet and outlet.

with any brushless setup you need an ESC for each motor, depending on size you can run them both on one large li-po like most of the smaller foamies with twin fans in them. I am guessing nacel size will dictate the size of fans you'll be using, I doubt it will weigh more then the glow setup but you might be around the same weight, also you will need to figure out the battery location while building it to get it to balance, it was designed for a glow engine and fuel tang to be up front, now the fans will be pretty far back, hopefully the battery will balance it, retracts would be cool, plus less drag and higher wing loading equals a faster plane which is always good in my book


here check this out for ideas, similar size/design, slightly larger so I guess either twin 101mm or twin 90mm, w/e the biggest that fits I'd say...[link=http://www.nitroplanes.com/new-edf-rc-jet.html]http://www.nitroplanes.com/new-edf-rc-jet.html[/link]

Here are some shots of the last build at the club. He built an old kit and glassed and painted. Wish he would have gone with fans!

At the weight you've mentioned, I would think a pair of 90mm fans are in order. 29 oz/sq.ft. wing loading is where the big dogs play. I'm partial to twin EDF's but I'm still mucking around with 68mm fans so I can't be much help.

gunradd is correct. Head over to RCG's EDF forum. The very best of the EDF-ers hang out there and will point you in the right direction.

Thank you very much for the feedback so far.

I will have to check the size of the nacelles, but I was expecting to have to create new ones to house the EDF's.

I will certainly check out the electric DF group at RCG.

Thanks again and I will post progress reports once I get the assembly going.

Also being someone that has done a ton of work on the full scale learjets the one in the kit looks like it was copied from a Lear25 wich had turdojet engines and small nacels. The lear35s used TPE731 turbofan engines with larger engine nacels so if you go EDF you could just say you have a lear 35 lol. It would still be very scale. You would also have a plane that you dont see everyday.