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        Discussion All balsa F3P take two, geodetic airfoiled wing

#1 dylan roberts Jun 29, 2012 03:00 AM

All balsa F3P take two, geodetic airfoiled wing
7 Attachment(s)
Hi everyone,

inspired by my previous balsa F3P ship that was 92g flying with a 240 2s lipo, i decided its time to push it as far as i can:

DT RX40 is less than a gram for 7 channels
5gram blade mcpx 11000KV motor geared to drive my 10.5x3 balsa composite prop.

i am aiming for 75grams flying weight.

so far the prop, its hub, bearing carrier, pulley and shaft weigh in at 3.9 grams, this is less than my std carbon props.

airframe is +- 900 long +- 850 span
concep so far.

#2 ChrisBowker Jun 29, 2012 08:21 AM

Beautiful work on the prop! thanks for sharing the pics, please keep them coming.


#3 Andycap Jun 30, 2012 08:52 AM

Prop is a proper work of art Dylan. F3P bling!

#4 steve gerrard Jun 30, 2012 04:06 PM

wow real nice work on that prop cant wait to see the plane, watching with intrest

#5 Not Free Jul 05, 2012 08:54 PM

wow!! that prop is wicked (in a good way:D)

Keep us posted on the plane please:):)!!

#6 dylan roberts Jul 06, 2012 02:23 AM

Thanks for the comments guys, should be getting the wing ribs Laser cut this weekend, not sure if the motor from HK will be here on time so might end up with my Microdan.

will upload more pics next week

#7 dylan roberts Jul 08, 2012 11:38 PM

8 Attachment(s)
some updates, the fuse is 11grams, its almost a meter long.

just pieced bit of the one wing together last night

#8 seuchato Jul 10, 2012 01:18 PM

Great and very inspiring work, keep it comiing please!



#9 sps3172 Jul 10, 2012 10:32 PM

Looks great!! Hope to see more pics as you progress....

I'm curious to see how you hinge the ailerons.

#10 dylan roberts Jul 11, 2012 12:07 AM

8 Attachment(s)
thanks guys,

i have overshot my goal weight on the wings and my lightweight equipment has not arrived yet, so it will me a more coventional 2cell setup. i guestimate 100 odd grams.

aileron root is driven directly by the servo and the tip hinges on a pin, rest just floats.

wings were 4.5 grams each without sheeting, sheeting added 4.5 :eek:

next time i wont sheet them, this structure is plenty strong enough without it.

1 wing and its aileron are at 14g so far.

#11 Ron Williams Jul 11, 2012 07:41 AM

This is going to be a hangar rash nightmare.

#12 dylan roberts Jul 11, 2012 07:51 AM

Ron, thats what happened to my previous one :D

but the mylar makes a pretty decent trash bag to keep all the broken balsa in ;)

im already planning the next build. i REALLY want to get the 75gram flying weight. our comp is this saturday so im rushing this

#13 Ron Williams Jul 11, 2012 11:32 AM

Good luck!

#14 midrian Jul 15, 2012 12:50 PM

I saw it fly yesterday at Hatfield Church and must say impressive :)

what did you cover it with?

you should post some pics of it completed while it hasn't been damaged yet


Great building btw

#15 dylan roberts Jul 16, 2012 12:05 AM

6 Attachment(s)
Well, after a full friday marathon build up to 5am on Saturday morning (thanks for the help Dad) i had it ready to fly.

i missed my design goal of a super lightweight builtup, but i learnt quite a bit in the process.

Model size:
980 long x 860 span
20% NACA airfoil section

120grams flying weight including battery.

i did not end up running the balsa prop, none of my single cell equipment arrived yet. aerie ended up way to heavy for that anyway.

flying wise i am super happy with the airfoil, amazing low speed characteristics and no tip stalling on sharp pullouts. Microdan 1700 KV swung the 10.5 inch prop no problems. rolls were VERY lazy and i think it will need some changes to the airfoil to sort this out.

all in all, pleased with the outcome, and inspired to push my skills yet again, i want that 75grams :D

Midrian, i ended up using 1micron mylar bonded with 3M 77 spray contact. the glue is a heavy solution, i will look at alternatives next time or perhaps tissue covering instead.

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