My F3J project - takes flight - Page 5 - RC Groups
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Jan 16, 2010, 12:45 AM
In F3J size does matter!
roydor's Avatar

I actually have a wiper on all rudders, even the one in the picture, it's clear so hard to see. It's basicly just clear tape.
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Jan 16, 2010, 01:02 AM
Detail Freak
target's Avatar
I see it now....
Jan 16, 2010, 02:09 AM
Registered User
Avaldes's Avatar

Fantastic thread! You have captured the techniques of molding an airplane perfectly! If you need a job at IAI, please let me know!

Jan 16, 2010, 11:04 AM
In F3J size does matter!
roydor's Avatar
Thanks Aaron,

I work in the UAV industry already so I'm good...
Jan 17, 2010, 03:18 AM
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Tuomo's Avatar
Originally Posted by roydor
djklein21, Iím thinking of several possibilities for a Eurotur, Bulgaria sounds interesting and should be fairly cheap, Italy and Holland sound nice too and of course if there is an open competition before the worlds in France that should be a very interesting competition (even though it wonít be a Eurotour one), Turkey is also a great competition (one of the best) but having been to Turkey several times before I wanted to take the opportunity to check other venues this year.
Last week we organized our entry to Bulgaria. But think again about France. Jura Cup seems to become the largest F3J event this far. Right now there are 213 entries... It would be nice to see Gremlin over there
Mar 10, 2010, 02:06 AM
In F3J size does matter!
roydor's Avatar
I thought I would give a little update,

Weather, flu and family and I have went flying the Gremlin just twice before last weekend when we had the first competition of the season here in Israel. I was still dialing in some of the mixes during the final round of the competition but the Gremlin performed very well. The conditions were tricky, light to no wind and very light air moving sporadically across the sky.
You had to constantly keep adjusting your position in the thermal. On one round I had to change the air I was flying in three times, even though I thought I was set for the round in some comfortable air about 5 minutes in, it just disappeared on me and I had to go looking for something new, found something better and again thought I was set but at 3 minutes to go it turned into sink and I went looking again for that little something to complete the round.
The Gremlin is unbelievably stiff, and the zooms are very impressive, I was flying off a 1.6mm line since I finished all my good lines last season and haven’t ordered new ones yet, and even with the completely unsuitable line for the conditions (1.2 or 1.3 would have been fine) I was launching one of the highest. The model still needs some fine tuning in the launch but it’s pretty much there.
The Gremlin signals air very well, probably due to the light tail and the handling is excellent.
The Gremlin is also a landing machine, the flaps are very efficient and having had no landing practice on the model I ended up having a 97, 98 and a 100 with good times on my best flights. Ended up in third place just 4 points behind the winner and one point from second place and I’m happy with the score.

I’ve also finished molding my second Gremlin, an all carbon wing with a reinforced fuse. It will take me some time to finish trimming the wings, mold the wipers in the wing and install the radio system (I even need to order servos and an RX) and I have a long business trip coming up so the model should fly in a no less than a month. It should come out around 2.2 kilos and has a 90 gram carbon skin and an even stronger spar. I took some pictures on a friends camera of the build and will put them up as soon as I have them.

Mar 13, 2010, 02:04 AM
In F3J size does matter!
roydor's Avatar
As promised, some pics from the carbon wing build.

I'm still thinking of a Eurotour compatition, I'm afraid the Jura cup was a little to far away to commite to (calender wise) and now its full. "Holland glide" is an option and I like the sound fo Bulgaria. I think that start of April I will decide on Bulgaria and if for some reason I can't go, I'll commite to "Holland glide"
Mar 15, 2010, 08:59 AM
Registered User
Roy, I assume the peel ply hinge is on the bias and well sheared. How does it compare to Kevlar in resisting tears along the hinge line.
Thanks for thr Pics - very professional.
Mar 15, 2010, 05:18 PM
In F3J size does matter!
roydor's Avatar
The peel ply is 0-90 orientation, it’s this way because that’s how it comes in the tape. I add additional material at the servo horn location and both ends of the moving surface to ensure that if it starts to tear it will hold at those locations and I could add tape to close the gap. It’s easier to work with then Kevlar and in my opinion has better tear resistance. Kevlar tends to "fuzz" at the hinge and eventually tear. Notice on any of the euro ships there is no Kevlar at the hinge. the only reason to make a Kevlar hinge is if you have a Kevlar skin.
I built a DLG rudder a few days ago and used peel ply and it's also much better looking than a brownish-yellow strike in the middle of a lovely flying surface.
Mar 15, 2010, 07:49 PM
Registered User
Thanks Roy. Good luck in your contests.
Cheers John
Apr 19, 2010, 05:12 AM
In F3J size does matter!
roydor's Avatar
I have finished the carbon Gremlin and test flew it this weekend. Basically copied the settings of the kevlar Gremlin and after a hand toss to find the correct elevator incidence I launched a first gentle launch and the model flew straight and true.
After a more accurate elevator trim was achieved I landed, moved the hook back to the more aggressive position that worked well on the kevlar Gremlin and relaunched, what a zoom!
A few flights later and the setup was good and I could start to test the performance, made some launching optimization an got familiar with the model.
The model is slightly heavier then I expected, about 2250 gram, much more robust (extra material in the pod and boom, thicker carbon pushrods, carbon 90 skin in the wing, wider spar, stronger joiner, more robust covering on the elevator), feels slightly different in roll and yaw due to the higher inertia of the wingtips (was expected) but still has excellent handling. The weather was not optimal for a test flight as the wind was ranging from about 4 m/sec when I started and up to 7 m/sec when I finished, the air was very turbulent and thermals were light, but the model flew well and I didn’t really feel a need to ballast. Launches were spectacular and I broke a 1.6 mm line on my winch (twice), it wasn’t a new line but still…

I am happy with the result and plan on using the model in the Bulgarian Eurotour in two weeks time, should be great fun.

I also flew the electric fuse with the Kevlar wings a short time ago, weight is 2.3 kg, climbs about 11-12 m/sec, handles well and the inertia is about the inertia of the carbon Gremlin, about 7 climbs on a single charge to 150+ meters so great fun and excellent for practice on those days you don’t feel like setting up a winch.

I will get some pics when I get the time.

Apr 19, 2010, 06:51 AM
Registered User
Thx for the repot , seems you are doing just fine with gremlin . Wouldnt say no to some pics also . GL
Apr 19, 2010, 08:01 AM
Detail Freak
target's Avatar
Congrats on success of #2.

Apr 19, 2010, 10:20 AM
Registered User
Congratulations you now have almost a full fleet - enjoy your reports, thanks .

Apr 22, 2010, 10:40 AM
In F3J size does matter!
roydor's Avatar
I'll get some pics of the two Gremlins this weekend.
In the meanwhile, pictures of the self holding my fuses at my workshop, itís a culmination of four years in the planning and making, two Gremlin F3J fuses, one electrified, one modified Perfect fuse and one electrified.
They're not much but bring me great satisfaction knowing the models behind them.

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