"Foamy Thunder"
11-26-2018, 03:23 AM
#1
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Join Date: Nov 2010
Location: Coffs Harbour NSW, AUSTRALIA
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"Foamy Thunder"
Rather interesting 90 mm powered EDF jet I got hands on in second hand junk shop. Not exactly my kind of model but after my offer was accepted I had to have it.
Never built 90 mm powered EDF running only on 4S so I decided to have a go with what ever bits I found in my spare part box.
The lightest motor I found was 3660 inrunner at some 1600kv spinning 9 blade rotor I cut down from 12 blade in Wemo shroud.
Running up to 700 watts at some 45A current it pulls up to 1.2 kg, which is the full weight of fully complete model with 4S/2650/60+C pack off 80A/ESC.
Recommended ready to fly weight on the box shows "430 grams", which makes me wonder how they came up to.
To make it more interesting I re-design it as a catapult launcher, by adding some ply skids to the belly with the shaped hook in the main skid under the nose, which was also extended by 50 mm to achieve correct CofG.
Number of other improvements were done to the frame such as installation of proper hinges to Elevon controls, re-mounting servos to the top of the wing to avoid possibility of damage during take off and landings and thrust tube was fitted to the nacelle for more efflux.
New foamy toy.
Selecting what power to fit.
Nose ext. and proper fan mount install.
Check of some figures.
Landing skids with the catapult hook plus ESC placement.
Bit of colour added.
Just about ready for some fun.
Never built 90 mm powered EDF running only on 4S so I decided to have a go with what ever bits I found in my spare part box.
The lightest motor I found was 3660 inrunner at some 1600kv spinning 9 blade rotor I cut down from 12 blade in Wemo shroud.
Running up to 700 watts at some 45A current it pulls up to 1.2 kg, which is the full weight of fully complete model with 4S/2650/60+C pack off 80A/ESC.
Recommended ready to fly weight on the box shows "430 grams", which makes me wonder how they came up to.
To make it more interesting I re-design it as a catapult launcher, by adding some ply skids to the belly with the shaped hook in the main skid under the nose, which was also extended by 50 mm to achieve correct CofG.
Number of other improvements were done to the frame such as installation of proper hinges to Elevon controls, re-mounting servos to the top of the wing to avoid possibility of damage during take off and landings and thrust tube was fitted to the nacelle for more efflux.
New foamy toy.
Selecting what power to fit.
Nose ext. and proper fan mount install.
Check of some figures.
Landing skids with the catapult hook plus ESC placement.
Bit of colour added.
Just about ready for some fun.
01-01-2019, 12:02 AM
#2
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Join Date: Nov 2010
Location: Coffs Harbour NSW, AUSTRALIA
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Maiden didn't go exactly to my plan but managed to bring it down after some sling shot fun ride!
After some serious knife surgery to remove the power unit the th/tube was reset with more up/th.
Waiting for some calmer weather to test it again, it's all trial & error.
After my first test flight it was bit of a handful, just the matter of luck I didn't wreck it. Some issue with the CG and thrust line. Extended th/tube created too much of d/thrust so I had to rip it all out including the rudder fins to shorten the tube, dramatically increase the up-thrust and for the next test flying sessions I have fitted simple landing gear to be on the safe side. Also extended the wig tips adding small winglets to make it more interesting.
Last edited by Joseph Frost; 01-01-2019 at 12:05 AM.
11-28-2020, 01:31 AM
#3
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Join Date: Nov 2010
Location: Coffs Harbour NSW, AUSTRALIA
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Never ending joy flying this fun jet after all these years, rather unique power set up after my modification of the power unit impeller, from 12 to 9 blades to reduce the current draw to push this huge 90mm set up at only 4S voltage.
The rarest EDF on RCU.
Pretty lively 90mm set up on 4S.
On the final.
The rarest EDF on RCU.
Pretty lively 90mm set up on 4S.
On the final.
