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Official Freewing JAS 39 Gripen 80mm EDF Jet
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Thank you very much!
I'll soon be posting more vids... first a compilation of mishaps (three crashes) that I finally found the root cause for, and then the first flights after the last repairs ^^
BTW, that was a cool vid, how did you make all that telemetry screen overlay? Cool stuff! :D
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Yep, it's been debated earlier. Using only the canards for pitch isn't a really bright idea.
Canards should be used in pitch only, but not the other way round (Canards only in pitch, that is), lol
Well, the plane survived so you can correct that mistake. Canards are there mainly for flow control indeed. And they also make a wonderful job at stabilizing pitch through a gyro on high gain without producing oscillations, so there's that too. ^^
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Originally posted by JetFun View PostI flew with pitch on canards only. They are "pretty ineffective".
The canards are close to the CG so any pitching moment they exert will be small. On the full size plane the canards are primarily for airflow control, not the primary pitch control.
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I flew with pitch on canards only. They are "pretty ineffective". Really needed to speed up a number of times to actually get them to to what I wanted them to do. Deflection was all up to about 4,5 cm. Long way to start..... So I would not bother using them for roll anyway if you have trouble programming them. Use them for added pitch and you will be just fine. Look at the huge deflections on the MIG-29 or F-22 and Gripen canards are in comparison just tiny. If you try flying with canards only - to see how effective they are - make sure you have a safe setup on another phase.
If you wonder about using roll and pitch on the canards - most transmitters need extensive workarounds as one direction is always wrong. Even when switching servo position on the receiver or reversing the direction. Simply because up and down works the other way around on the canards compared to a normal delta tail. If you have fun programming go for it - otherwise don't bother.
What works fine is a 4-5mm up deflection on the ailerons during landing with no compensation from the canards. Results in a nice high landing alpha and slows down nicely. I flip the switch about 5 -10 meters above ground.
I fly 50 - 60% expo. Always did that on 3d aerobatic aeroplanes.
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Personally, I tried to get all the deflection I could mechanically on the canards. On the elevons I think I put the linkage one hole more inwards than recommended to gain some extra throws. I then smoothed it all out with expo. I have the servos set to deflect to their maximum. Once I do that, I may slightly limit the throws to avoid asymmetries in throws or to prevent control surfaces binding at the limits.
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Originally posted by JetFun View PostHow many mm are your deflections for the elevator functon in the rear (ailerons) and the canards? Not sure how many mm I should use on the elevators for the pitch function.
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How many mm are your deflections for the elevator functon in the rear (ailerons) and the canards? Not sure how many mm I should use on the elevators for the pitch function.
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Originally posted by WarbirdFan66 View PostIf one of you guys need a few unnecessary but cool looking 3d printed extra parts for your Gripen , like for storing or on Display at the field, here a few intake and exhaust covers for your GRIPEN (but keep in mind you need a bit of a 4mm softrubber cord to complete them )...you can find them on thingiverse under JAS39, blue skys
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If one of you guys need a few unnecessary but cool looking 3d printed extra parts for your Gripen , like for storing or on Display at the field, here a few intake and exhaust covers for your GRIPEN (but keep in mind you need a bit of a 4mm softrubber cord to complete them )...you can find them on thingiverse under JAS39, blue skys
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Haven't visited in a while but another thread got me going so I gotta share. I absolutely love my Gripen now. I'm flying it with an XFLY 80mm 12 blade 2200 Kv fan, 6s 4000 mAh 60c batteries, and Eagle A3-L gyro. I have the canards working pitch only. It is sooo light and the power is good. Nothing I own is better for super tight maneuvering and it just will not stall. With the power I can always blast away from any "situation" without sinking. But yeah, those main gear doors! I take off into a vertical, reduce power and raise the gear while doing a hammerhead stall, works like a charm :)
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Originally posted by jasmith41 View Post
That's because you're a crazy man... 🤣🤣🤣👍
Originally posted by Radar-Guy View PostNot working with a decent 8s fan, she accelerates vertically
That said, my addition of a mosquito net on the cheater to protect the EDF limits my fan performance and also, despite my attempts at protecting it, the rotor is getting chipped already.
Anyway, I crashed again the Gripen and in the repairs I'm getting rid of the wing spar and spar sleeve so that should improve substantially my thrust output. Weight savings are about 30g.
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