ThomasB:

Did that plywood raise up the trailing edge of the wing and if so how did that effect it's flying.

Jack

Originally Posted by pjdog350

ThomasB:

Did that plywood raise up the trailing edge of the wing and if so how did that effect it's flying.

Jack

I can tell no difference at all in how it flies with the motor assembly installed. It actually does not get a full 1/32� raising the trailing edge. I need to get a picture, but if I recall correctly, the motor mount centers on the round plastic rods that receive the wing screws and not on the the screens themselves. I believe this allows a bit of compression of the foam wing and fuselage so that there is no significant incidence change.

In any case, it is a great flyer with this mod.

I have two of these UMX ASK-21s for sale. I have listed one of them in the classifieds. I would have listed both, but people usually just want one at a time anyway.

Link to Classified ad

Anybody still flying theirs?

I'm way late to the game but I recently picked one of these up and I've been enjoying tinkering with it. I ended up messing up the airframe of a UMX Radian so today I got a new Radian and swapped the old Radian's motor onto the ASK-21. It flies surprisingly well, more of a sustainer motor than a real motor glider but it'll slowly climb to altitude and glide around nicely. Coupled with the hi-start this'll be a fun way to extend flights and find thermals. Initially, I tried to swap the ESC brake over but the output pins on the ASK-21 brick are set up differently than the Radian and won't activate it properly. I'll need to do some further testing to see if I can wire it anywhere else on the board.

In my test flights tonight, I was able to get the prop to reliably fold by pitching up hard after taking out the power, letting the plane momentarily stall which dropped the prop blades back against the fuselage where they'd stay until I used the motor again. It sure looks great in the air! It even flies nicely at full power, just gently cruising around and maintaining altitude.

If anyone has another one for sale in good shape with the box and original accessories, I'd be interested in buying it!

@Rota - That's awesome! I have a full UMX Radian electronics waiting to do this mod. Trying to source another UMX ASK-21 as well.

Can you post up detailed photos of the motor mounting and the bits how you got it stuffed in there?

Cheers, Thompson

Originally Posted by studioRS

@Rota - That's awesome! I have a full UMX Radian electronics waiting to do this mod. Trying to source another UMX ASK-21 as well.

Can you post up detailed photos of the motor mounting and the bits how you got it stuffed in there?

Cheers, Thompson

Save yourself some waiting time with examples already are posted! Under Thread Tools tab simply use the 'show attachments for this thread' to find several examples of motors that were installed onto the Ask-21.

@CorvetteC5 Nice idea, never searched that way. I’ll even see all the photos I posted about mounting a brushless motor and Graupner folding prop in the nose. Looking specifically for any mountings of the geared Radian motor. Thank you.

Originally Posted by studioRS

@CorvetteC5 Nice idea, never searched that way. I’ll even see all the photos I posted about mounting a brushless motor and Graupner folding prop in the nose. Looking specifically for any mountings of the geared Radian motor. Thank you.

This link from 2013 may be helpful:
https://www.rcgroups.com/forums/show...2#post26231693

It shows my installation of a Nine Eagles brand 8.5mm motor and 4:1 ratio gearbox which is very similar to the E-Flite UM Radian setup. Plus I include some clear pictures!
Good Luck!

Originally Posted by CorvetteC5

This link from 2013 may be helpful:
https://www.rcgroups.com/forums/show...2#post26231693

It shows my installation of a Nine Eagles brand 8.5mm motor and 4:1 ratio gearbox which is very similar to the E-Flite UM Radian setup. Plus I include some clear pictures!
Good Luck!

This is PERFECT! Thank you for the refresher link, and detailed notes. I've already started on building a larger 1m scale wing.

@Corvette C5 - Think my plan is to build this last remaining ASK-21 fuselage spare part I snagged, somewhat similar to my last attempt way back in 2013.

Except, this time the differences will be as follows:

- Building out a 1m wing of balsa and Sitka Spruce (spare wing part is NLA). Wing will have full length ailerons. The plan Im using is actually for a https://shop.vth.de 1.42m ASK-21 mini made of Depron. I've reduced the wing size down to 1,0m and reorganized the plans so I can print out on 8.5x11 sheet.

I've built the left wing and bare balsa (not covered yet) glued up comes in at 13 grams. (for comparison, the factory UMX ASK-21 wing with two servos and some of my clear laminate scale stickers is 33 grams).

- Build out elevator, tail and rudder of balsa (spare tail/rudder/elevator part is NLA).

- Up the motor to better suit the smaller 4,7 prop � BR1811 3800kv motor, but loose the wood mount and four metal screws I used. I'll use hard foam to secure the aluminum motor mount and glue that to the fuselage.

- Use same Graupner 4,7x2,4 prop (Best Nr. 1336.12.6) and Hobby King spinner (SKU: OR025-02602).

- DSM2 6 Ch Ultra micro AS3X Receiver BL-ESC EFLU4864

- E-Flight 2.3 gram liner long throw offset servo SPMSA2030LO
One servo will be used for the ailerons (create same set-up as Nine Eagles Sky Surfer)

More photos of progress.

The wing seems to have turned out really well.

More photos of progress

Ailerons drafted in. I decided to replicate original version as close I could.

Originally Posted by studioRS

Ailerons drafted in. I decided to replicate original version as close I could.

Hi StudioRS - just came across this thread - did you ever finish your project here, and if so, how did it work out?