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Oct 28, 2017, 07:42 PM
flying beam
blackmoon's Avatar
Nice!

Which prop do you use ?
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Oct 29, 2017, 04:43 AM
Registered User
RNAF's Avatar
It's a prop I still had laying around from my Ikarus Eco Piccolo. It's about 70-75mm diameter.
https://shop.ikarus.net/en/eco-picco...iccolo-v2.html
Oct 29, 2017, 05:16 PM
flying beam
blackmoon's Avatar
OK thanks

I was going to buy some Br1103 6500KV and made a mistake (never buy something when it's way past your bed time ), got a couple of 8000. So when I saw you using that one , I regained hope ([email protected] is pretty impressive)
Last edited by blackmoon; Oct 29, 2017 at 05:27 PM.
Oct 29, 2017, 06:49 PM
Registered User
RNAF's Avatar
Also have the 6500kv but have yet to try them. Was hoping to go to a 4" on those.. Not disappointed with the 8000's, even though they are not the most efficient motors.
http://www.bsdmicrorc.com/pdfs/products/Didel-7mm.pdf
Oct 30, 2017, 10:50 AM
flying beam
blackmoon's Avatar
Thanks for the link, I'm always amazed at the "inefficiency" of these small motors and gearboxes.

I always think they are in the 80ish % efficiency, but no...
Nov 02, 2017, 07:04 AM
Registered User
RNAF's Avatar

Micro StingRay Kits with Video and Plans


Flew it again today, again in some wind but less gusty. I moved CG forward but still slightly behind plan indication.
Absolutely love it, it flies very similar to my Weasel Trek on which I've logged many hours on the slope 😊
It's very agile at full throttle but it stays aloft a lower speeds well. Will measure the throws I have and see to increase them a bit to have access to that agility at half throttle. Looking at 35% expo now.
Last edited by RNAF; Nov 02, 2017 at 07:13 AM.
Sep 05, 2019, 08:45 AM
Registered User

Micro Stingray stability question


This is the Micro Stingray I build from 3mm HobbyKing foam board. I added a KFm2 section - mostly for strength, but also to improve aerodynamics. The motor and brick are from an HobbyZone UMX T-28.

My problem is that it is pretty uncontrollable and I think I know why. I set my radio to leave SAFE off but I think the AS3X is confused because the brick is mounted upside down. Ideally, I need to disable SAFE which I will do but I'm not sure how to "reset" AS3X to accept that "up is now down", etc.

If I can get that worked out, this is small/light enough to fly in my front yard and (theoretically) impress the neighborhood kids. The all up weight, even with the KFm2 section, is lower than the T28 from which the brick and motor came so it definitely has plenty of power
Sep 05, 2019, 11:05 AM
Go small or go home
ruzam's Avatar
Quote:
Originally Posted by kdc914
I set my radio to leave SAFE off but I think the AS3X is confused because the brick is mounted upside down. Ideally, I need to disable SAFE which I will do but I'm not sure how to "reset" AS3X to accept that "up is now down", etc.
Not just upside down, but one servo is meant to control rudder. So any turning motion is going to throw that servo off and mess with one side of your aileron. I'm kind of surprised it's flyable at all with AS3X enabled. That would be a handful!
Sep 05, 2019, 11:07 AM
Go small or go home
ruzam's Avatar
Or rather, one servo was intended for rudder and the other was intended for elevator. So up/down motion will affect one aileron, and side to side motion will affect the other.
Sep 05, 2019, 11:22 AM
Registered User
Quote:
Originally Posted by ruzam
Or rather, one servo was intended for rudder and the other was intended for elevator. So up/down motion will affect one aileron, and side to side motion will affect the other.
I fixed that with TX programming before I ever tried to fly it. Changed the rudder channel to be left elevon and elevator channel to be right elevon (or vice versa). Verified they worked as expected. I think my only problem is the upside down board confusing ASX3. Of course, I could still be wrong but at least I did confirm that control surfaces move as expected with the TX sticks.
Sep 05, 2019, 02:53 PM
Go small or go home
ruzam's Avatar
I get what you're saying about changing the channel setup in your transmitter. But fixing it in your transmitter, doesn't change what channels the AS3X thinks are doing what. As far as the receiver knows, it's still working a rudder and elevator and applying changes it senses in orientation accordingly. You should be able to get some sense of how the how the AS3X will react by holding the plane and tilting it to see which servo correction gets applied. I'll bet it's not "correcting" in a way that helps your flight envelope I could be wrong, but I think you might also have to be giving it a wee bit of throttle for the AS3X to kick in and do it's thing.

One way to make the AS3X work in your favour would be to use a mechanical mixer of some sort to mix the elevator servo with what used to be the T-28 aileron servo. But on something this small that's clearly extra weight you don't want. Off the top of my head, I'm wondering if you tilt the receiver to a 45 degree angle (ie, left side down, right side up) so that rudder/elevator gyros are on a different axis. You'd have to work through the logic of what correction is applied in what direction. It may mean switching which servo/direction goes to which aileron.

Best bet is to find a way to reprogram the brick to disable AS3X. I know some UMX boards you can, some you can't.
Sep 05, 2019, 07:58 PM
Registered User
Quote:
Originally Posted by ruzam
I get what you're saying about changing the channel setup in your transmitter. But fixing it in your transmitter, doesn't change what channels the AS3X thinks are doing what. As far as the receiver knows, it's still working a rudder and elevator and applying changes it senses in orientation accordingly. You should be able to get some sense of how the how the AS3X will react by holding the plane and tilting it to see which servo correction gets applied. I'll bet it's not "correcting" in a way that helps your flight envelope I could be wrong, but I think you might also have to be giving it a wee bit of throttle for the AS3X to kick in and do it's thing.

One way to make the AS3X work in your favour would be to use a mechanical mixer of some sort to mix the elevator servo with what used to be the T-28 aileron servo. But on something this small that's clearly extra weight you don't want. Off the top of my head, I'm wondering if you tilt the receiver to a 45 degree angle (ie, left side down, right side up) so that rudder/elevator gyros are on a different axis. You'd have to work through the logic of what correction is applied in what direction. It may mean switching which servo/direction goes to which aileron.

Best bet is to find a way to reprogram the brick to disable AS3X. I know some UMX boards you can, some you can't.
hmmm... OK, much to think about and research. Thanks.
Sep 05, 2019, 08:05 PM
Registered User
Quote:
Originally Posted by dz1sfb
well crappity crap crap. Target Hobby seems really sketchy now - no https, unregistered security certificate, and several other things that make on old IT guy pause. The old adage, "if something seems to good to be true, it probably is" applies because, in this day and age, "better safe than sorry" MOST DEFINITELY also applies. That price is SO tempting given prices for similar gear everywhere else which, to me at least, is just another red flag. This saddens me because I REALLY enjoy flying ultra micros at the park near my home rather than the 30 minute drive to the club field for anything larger.
Sep 06, 2019, 08:45 AM
Registered User
Adding a KFm2 section moved the center of lift of the wing forward so the plane would appear tail-heavy. Somehow you'll have to move the CG forward to coincide with the center of lift or the plane will be uncontrollable.
Sep 06, 2019, 04:14 PM
Registered User
Quote:
Originally Posted by steve_rc
Adding a KFm2 section moved the center of lift of the wing forward so the plane would appear tail-heavy. Somehow you'll have to move the CG forward to coincide with the center of lift or the plane will be uncontrollable.
D'OH! didn't think of that. As it is now, I couldn't get the CG far enough forward and am already BEHIND the recommended, much less farther forward to account for the KFm section. I have the battery all the way forward but I guess I'll have to turn it sideways.

Funny thing though, I did the same to my MINI Stingray (middle sized one) and the balance point was right on the plan-recommended CG. It flies great.


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