All things ASK-21 UMX!!! - RC Groups
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Jan 15, 2013, 05:16 AM
Member #1
Teamsherman's Avatar

All things ASK-21 UMX!!!

Hey folks,

There is starting to get a little bit of a cult following with this little beauty glider, so i thought id start a thread for all things ASK-21.

Maybe some posts like longest flight off the stock bungee and flying tips ect.

Last weekend a few of the Hammo guys had there little ASK's out for a bit of fun and as there were 2 carbon cubs there too, it didnt take long for the tow's to get going! Without much luck, i came up with the idea of using my Multiplex FunCub to tow them up!! But, being such a larger plane than the glider, it was just too much pull for the glider to handle.

Bing!! on went the idea light in my head once again, so i have a fully controllable RC freefall skydiver that is dropped out of a drop box on the bottom of the FunCub, the FC being piloted by usually Mr.K and the freefall skydiver controlled by whoever wants a jump at the time. The freefaller is fully controllable from pulling the chute, to flaring on landing!! But thats another story, if you want more information on the skydiver just PM me and i can start a thread for Punxatawny Phil the freefaller.

So i decided to mount the drop box on top of the wing, over the CG of the FunCub cause its literally just velcroed onto the plane (HK's blue velcro, its strong as nails) and voila! Instant piggy back!!

The first few flights were a little hairy as the speed of the cub and the drag on the gliders wings was a little too much for the proud owners of their little bubs, so we decided the only way up is quick, and vertical!! The FC is way overpowered and is often seen being 3D'd by Mr.K after a para drop!!

Once we had a few successful flights piggy backing we were going up one after the other, it turned out to be an awesome way to get them to altitude where they could get longer glides, and the guys were nice enough to let me have a little flight down and i ended being the longest up there!! lol

Crashmatt and myself have both spent the last 2 nights dreaming then making up a few little power pods to get the gliders to altitude with power, then eject the pod to see it parachute safely to the ground for the next flight!! Both our pods are very different in design, but both are powered by the internal electrics found on most of the UMX range like the GeeBee and BeastX ect.

To have control over the throttle, we bind the 2 receivers at the same time so when climbing the glider pretty much becomes a powered glider, when at the chosen height we want to glide back from, we use the gear switch that disconnects the tow hook thats attached to the front of the pod and nose down and throttle up till we see a deffinate separation, at that stage we hit throttle cut or throttle down and the pod should be falling back with a nice slow descent rate. Well, all that is theory so far as we havent maidened the pods yet, but will do tomorrow morning and report back on how they went.

For now, here is the pic of the FunCub with the ASK-21 on its back ready for a piggy back!

Here is one of the pod im building very early on in its build stage and the electrics i'll be using thanks to Matt!!!

Essentially, the pod is a centre piece from an old Zagi 400 wing i have spares of. The 2 sides are corflute where the wings will be saddled in, and at the nose you can just make out the small metal wire where the tow release mechanism locks in. The motor esc/rx with be fixed to the bottom of the pod and the parachute will be packed in under the belly of the glider. Its all slightly snug, enough that the chute wont pull out on power but not too tight that the pod wont pull away from the glider.

We got the pod idea from this video:
E-Flite UMX ASK-21 Glider Power Pod Upgrade in HD By: rcinformer (8 min 50 sec)

But unlike in the video, we wont be using a kill switch. We did buy the switches and plan on using them, but though it easier to just utilise the throttle and throttle cut off.

Enjoy the thread, i look forward to some more pilots checking in!!!
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Jan 15, 2013, 06:12 AM
MclF1's Avatar
very nice thread to start TS
im also after the ask-21

thats such a great idea now why didnt E-flite think of that
Last edited by MclF1; Jan 15, 2013 at 06:20 AM.
Jan 15, 2013, 06:34 AM
Tassie Electric, Heli, Glider
ChrisJ800's Avatar
The k21 is a nice little sloper too. Here is a vid of me sloping it in Taz. Sorry its from an iPhone and the slope had the lift a long way out so its not great quality. It slopes with AS3X either on or of nice and spins loops and fles inverted ok. Rolls not so good yet.

Slope soaring UMX ASK 21 (0 min 51 sec)
Jan 15, 2013, 07:49 PM
Member #1
Teamsherman's Avatar
We tried one of the pods today (Matt's bling one) and it was slightly under powered but flew well. Only real problem had was that the wing cradles were slightly too tight not releasing off the glider so I think he's at home fixing that as I type.

I've got all the necessary parts now so I'll get mine done this afternoon hopefully and give it a try soon. I'll get a pic up of the finished product too.

On another note, I tried the supplied bungee and that was quite disappointing to say the least! I think the pods and FunCub piggy back are going to be the best ways to get this thing to thermal hunting height.
Jan 15, 2013, 09:50 PM
Registered User
ChuckTseeker's Avatar
was in winter so no thermals but this little glider is a beauty, here is a couple of my bungee launches.
Also a couple of posts with power options

cheers chuck

E-Flite UMX ASK-21 Glider Bungee Launch Maiden (7 min 51 sec)
Jan 16, 2013, 12:50 AM
Member #1
Teamsherman's Avatar
Edit. Vid coming.
Jan 16, 2013, 01:59 AM
MclF1's Avatar
could you make a bungee to say 30m long would that work?
Jan 16, 2013, 01:18 PM
Registered User
Crashmatt72's Avatar
Ask-21 Power Pod Mod Maiden (2 min 0 sec)

Short clip of the first power pod maiden, mods needed. But has potential!!
Jan 17, 2013, 01:26 AM
This thing runs real nice...
Nam Lemmi's Avatar
This a short vid of my ASK-21 slope soaring. Flies inverted very well I thought!

E-Flite ASK-21 slope soaring (2 min 34 sec)
Jan 17, 2013, 03:53 AM
3 Strykers,your out !
junglegym's Avatar
Last edited by junglegym; Jan 17, 2013 at 04:11 AM.
Jan 17, 2013, 05:12 AM
Registered User
Crashmatt72's Avatar
Originally Posted by Nam Lemmi
This a short vid of my ASK-21 slope soaring. Flies inverted very well I thought!
Nice flight, it slopes great!!
The bungee and tow are a waste of time.
Keep up the nice flying
Jan 17, 2013, 05:18 AM
Member #1
Teamsherman's Avatar
Ive finally finished my power pod this evening!!

I'll give it a go tomorrow morning or afternoon, depending on if i decide to sleep in or not, i think i might sleep in actually!!! lol Plus, if it gets as hot as they say, i might want to fly in the heat of the day to get thermals, that said, its only if the pod works!! I powered it up with a load this arvo and held it vertical, and it wanted to climb out of my hand so it should do, but the main concern i have is if the glider will release from the pod or not, just like Matt's didnt want to release.

If that dont work, im buying a helium tank, a big arse balloon and a beach rod with about 200m fishing line to float the sucker up, then wind the balloon back in for another flight, but im guessing it wont work too well once the wind comes up!! LOL
Jan 17, 2013, 05:25 AM
Tassie Electric, Heli, Glider
ChrisJ800's Avatar
Here are a couple of vids launching the K21 using a Quad, originally posted on the main ASK21 thread:

Quadcopter Tows Glider (0 min 52 sec)

Quadcopter - ASK-21 Glider launch (1 min 42 sec)
Jan 17, 2013, 05:27 AM
Registered User
Crashmatt72's Avatar
Awesome work with the mods Junglegym!
Jan 17, 2013, 09:01 PM
Member #1
Teamsherman's Avatar
UMX ASK-21 Power pod mod (0 min 45 sec)

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