Balance a Micro EDF video

Thanks to Ambraske for the heads up on the Aeromodeller Magazine article.  I bought the electronic copy for $5.99 and found this link to balancing EDF's: Click Here

Very informative article and I'll re-read it several times and keep it for referral insights!

Tom

There's lots of info out there on several sites about making plans from 3-views.  With the three views there are the basic outlines.  Most guys recommend enlarging the horizontal stab about 20 percent for stability.

I'll try to find a link for y'all. 
Here's a good link for 3views:  http://www.rcgroups.com/forums/showthread.php?t=557457

Tom

Here's a particular response from Copbait73 on HPA their EDF thread that I've found most informative.
Tom/ALL-
Well here is a quick download of my experiences and preferences:
Don't like straight wing subjects, you will break the wings - sorry.
Use dihedral, flat swept wings look scale but the model will not last long.
No cracked ribs or sliced. Use stiff leading and trailing edge materal/ web your spars.
Place all the hatches on the bottom. The landings are fast and heavy, compared with rubber, make the hatches solid balsa. Double cover bottom of fus not planked.
Attach all hatches with nylon screws. Magnets are a waste of time.
Plank the nose up to the wing root.
Plank the fus at the C/G location so you can get a good grip for postive launches.
Do not build in any of the electrical components or fan unit. They will need removal from time to time.
Make a craddle mount for the EDF unit.
Consider the inlet on a subject like the Mig a flownozzle then make duct the same size as the O.D of the fan unit.
Do not be afraid to cut a cheater hole in the belly.
Do not choke down the tailpipe as R/C guys do, it kills the static Thust needed for hand launching. Make the tailpipe no less than 1MM under the I.D. of the fan.
Add down thrust and left/right thrust tabs at tailpipe. Start with 5-10 degrees down
Use brushless EDF units only, brushed motors do not make high thrust and are not reliable.
Use Hyerion LiPo batteries. Do not carry any more battery than what is needed for one 2 minute flight.
Use Castle Creation ESCs
Use K&P controllers
Charge with a K&P dual function jack, charge/on-off switch
Use Great Planes 30MM and K&P 24MM. All others are inferior
Thrust to weight should not go over 2.5gms gross weight to 1gm static thrust.
Wingloading can be high if thrust to weight matches above. Successful flight is more a matter of thrust to weight than wingloading. Both my BV212 and XB-42 models fly at 1.75gms per square inch. Very high by FF standards. Less is always better.
Know where you C/G is at all times.
Do a graphical calculation of the C/G at 30%.
Set the face of the fan unit on or near this location.
Balance the model to this on a wedge, fingers at the tips are not good enough. Begin glide testing without the fan and electical components installed. Adjust stab for proper pitch control. Glide shoud be dead straight.  You do not want a nibbling stall like rubber. Stall is to be avoided as most will not recover...its a jet.
Mark your final C/G on model and build plan.
Install systems then rebalance.
Check glide.
Set thrust at 25% or lower and 5 seconds. l
Hold model at C/G if possible, with other hand hold nose at a level pitch attitude.
When fan revs up hold for a second for power to stabilize.
Launch into the wind with authority, no wimpy rubber flip here. No wind launches may duplicate early jet carrier launches....your jet will dip a couple of feet gaining the flight speed needed for climb.
Your model will torque turn, use L/R thrust tab and a dab of weight on the high wing. Avoid aerodynamic changes to counter the turn. Jets will bank turn, do not even try a flat turn like rubber.
Slowly add thrust and time unti you climb out and make one fairly open circle. Watch the glide and make small nose or tail weight adjustments to alter it to flat and fast. usually it will glide turn counter to powered flight.
Build a jet and lets mass launch.

Tom

I found this information on the RCGroups site but the theory is the same for free flight models regarding the EDFs.
http://www.rcgroups.com/forums/showthread.php?t=742798

I am a newbie when it comes to EDFs so I'll be learning as I go and will welcome any and all input from those more experienced and those interested in this new facet of stick and tissue free flight.  I know the link above is for RC models and if there is interest in the RC versions we can start a board for those models as interest arises.

There are some posts on HPA site as well and this is a very intriguing new vane of modeling that I look forward to exploring.  Math isn't my forte but it does stretch my brain power and there is some math in the above link.  Feel free to join in with any questions and insights and any projects you have on the building board.

Several of the modelers are adapting rapier designed jets to the micro EDFs.  Lets see what you got or would like to see.

I like the early jets and the Century Series jets so here's my first draft plans for the F3H Demon by McDonnell from the late 50's. Still have some changes to make on this one.
Tom