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Old Nov 05, 2012, 03:45 PM
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yorkshire UK
Joined Oct 2007
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Agreed stock motor is not very good, mine is just about surviving but only because I use it carefully ie full power for only 20 to 30 secs followed but a long glide with a good 5-10 min rest between batteries, not ideal and speed is not good on power but is achieved by diving with power off, but your motor sounds worse and I would say is needing changing.
BTY I never test my motors for more then 10 - 15 seconds on the ground as the cooling will not be working and motor will overheat much more then in the air, I recently bough a tiger moth and the instructions said to test power for 1 minute on ground and everyone who did this burned out the motor and esc and required new ones, I did not do this and have had many flights with no motor problems!
It's a shame the manufacturers don't just put in bigger motors and esc in the 1st place and charge another $5 to cover the extra cost to them and we would be much happier and not have to mess about upgrading.

I made vents both in spinner and exit holes in fuse.
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Old Nov 05, 2012, 04:01 PM
Registered User
Austria
Joined Jan 2004
7,453 Posts
Quote:
Originally Posted by nigelsheffield View Post
Agreed stock motor is not very good, mine is just about surviving but only because I use it carefully ie full power for only 20 to 30 secs followed but a long glide with a good 5-10 min rest between batteries, not ideal and speed is not good on power but is achieved by diving with power off, but your motor sounds worse and I would say is needing changing.
BTY I never test my motors for more then 10 - 15 seconds on the ground as the cooling will not be working and motor will overheat much more then in the air, I recently bough a tiger moth and the instructions said to test power for 1 minute on ground and everyone who did this burned out the motor and esc and required new ones, I did not do this and have had many flights with no motor problems!
It's a shame the manufacturers don't just put in bigger motors and esc in the 1st place and charge another $5 to cover the extra cost to them and we would be much happier and not have to mess about upgrading.

I made vents both in spinner and exit holes in fuse.
I think I will try your flying style .. few seconds of full power for climb .. and then "long" glide for cool the engine ... with current set up ... mine take ages to climbs

Now that is winter, I should be fine ... when it will be hot, I may go back to 3s power ... or just park this bird ... I have tons of birds to fly and many still to finish to build ... but this is my first 2m wing span, and first supposed real glider ...

Can you show a photo of your vents in the spinners and the hole in the fuse?

In all my test, this 20amp rated esc never got warm, not even with 4s ... so maybe is the only safe part on the power line ... clearly if I will go for the 420w power motor from HK ... I will need also a different ESC

Btw ... thanks again for valuable experience sharing on this bird ...
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Old Nov 06, 2012, 02:51 AM
Registered User
yorkshire UK
Joined Oct 2007
3,732 Posts
I have posted my mods here somewhere, if u look through my posts you will see them, or just search for cooling vents and you will find them.
My esc gets hot as well as the motor and climb outs are fairly good if not spectacular, so your motor is certainly not right, like you say it sounds like a lower kv.

Dont judge all gliders by this standard though, this does not thermal well and is really only good for sloping and airobatics. If you want a good thermal ship for cheap the 2 meter asw28 is greathttp://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=8372, flies for 20 mins easy on 2 cell 1000mah and on a good day will stay up for hours.
The minimoa is not bad either but has the same power problems as this one and is a tad heavy so does not thermal as well as the asw28!
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Old Nov 06, 2012, 04:27 AM
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Austria
Joined Jan 2004
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Quote:
Originally Posted by nigelsheffield View Post
I have posted my mods here somewhere, if u look through my posts you will see them, or just search for cooling vents and you will find them.
My esc gets hot as well as the motor and climb outs are fairly good if not spectacular, so your motor is certainly not right, like you say it sounds like a lower kv.

Dont judge all gliders by this standard though, this does not thermal well and is really only good for sloping and airobatics. If you want a good thermal ship for cheap the 2 meter asw28 is greathttp://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=8372, flies for 20 mins easy on 2 cell 1000mah and on a good day will stay up for hours.
The minimoa is not bad either but has the same power problems as this one and is a tad heavy so does not thermal as well as the asw28!
I have my own searching system ... just look at all the picture of the thread ... here there is a link that do this job ... but I did not see any photo here with holes ...

Maybe you did not attach the photo, but just past a link to a different photo holder in the net ... in the case my search system would not work

Going to search later on maybe I can have better luck ...

One question ... did anybody change the central "metal" bar, that connect the two wings ... in order to reduce Dihedral ... and have more aerobatics ?
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Old Nov 08, 2012, 01:51 PM
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yorkshire UK
Joined Oct 2007
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Just take off the spinner and drill some holes in it to allow air flow through it, and cut a little bit of foam out under canopy to let the air out again.
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Old Dec 27, 2012, 03:34 PM
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USA, FL, Safety Harbor
Joined Sep 2000
135 Posts
ASK-21 Stab Attachment failure

Quote:
Originally Posted by iflytailies View Post
Although I categorized this thead "Build Log", there is very little to do to complete this model. But let's start at the beginning:

This is a 78-3/4" wingspan ASK-21 by Art-Tech. It's made of EPO foam and available from Hobby-Lobby as a receiver ready version. I orered the RTF version, which is no longer available from Hobby-Lobby.

Here is what the box looks from the outside

http://www.iflytailies.com/
I'm not sure where to post this as there is no official "notes, warnings, and cautions" section in our Forums.
Today I pulled out my ASK to fly. Last flight was 12 months ago after competing against 30 other flyers. After 5 minutes of climbing/thermalling and diving I noticed about a 5 degree stab tilt and "lateral play". I landed and found that the bolt to metal nut was very tight but the stab was not secure to the foam fin. I removed the bolt and stab and screwed the bolt back in. Gave the bolt a tug and the bolt and plastic fin piece completely separated from the foam fin. The factory glue failed after about 50 flights and the remaining glue was just enough to keep the stab from departing the stab/fin socket.
You can glue the stab "permanently" onto the fin but the plastic to foam bond will still be weak because of the factory glue. I plan on removing the factory plastic glue and replacing it with a stronger plastic to foam glue. Additionally I will be adding straps that will make the plastic to fin bond much stronger.
Recommend all flyers pre-flight their stab and check "lateral play" before launching. You will be able to catch and prevent your ASK stab from separating and causing an injury to persons, places, or things.
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Old Dec 28, 2012, 03:59 AM
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United Kingdom, England, Malpas
Joined Mar 2011
43 Posts
I have not been getting email notifications for a while for this thread so I have had a long read to "catch up".

@ Vic T and all = Yes I too had the tailplane come loose. I fixed it by drilling 2 long deep holes down the fin and epoxying wood dowel into these holes. I then drilled thin holes into the dowel and fastened the tailplane to the dowels with some very long very thin screws. It is now very firmly mounted with the bonus that the fin is now more rigid.

I posted a few pages back about the mods I did to the main wing mounting arrangement. Mine has been no problem since doing it.

I still have the stock motor, esc etc, but I have a bigger LiPo now. I have had no problems with power or heat, but I do not use the motor on high power for any long time. Just for climb out mostly and the occasional burst for parts of aerobatic flight, like the first part of a loop for instance.

Many many flights in now and still loving it



I did post a while back re "mixing" the ailerons as "spolierons" to reduce the VERY long final approach and despite some folks saying "yes give it a try" I never did (yet !) But I note "easy flyer" above has tried this. Hey, can you tell us exactly what "mix" you did and is it very successful ?
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Old Jan 05, 2013, 02:27 PM
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Austria
Joined Jan 2004
7,453 Posts
Just try today with 4s on stock PNF set up ...

And so far so good ... I did set a 3:30 timer on my tx (only with power over 50%) ... but at 3:00 of this timer I did feel it got weaker, and I landed ... battery was 3.82v on every cell, motor was cool ... so maybe was a wrong feeling ...

Outside temperature was only 6deg ... so I was counting on no motor temp issue

Anyhow, nut much improve on top speed, but climb rate is much better now ... so much more enjoyable now

Few seconds of power ... and then nice gliding

This was also my first fly for the year

Tchuss

E_lm_70
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Old Jan 13, 2013, 06:36 AM
I have Imajinary Airplanes
7 Miles from Turkey Hill Slope, PA.
Joined Mar 2003
656 Posts
A couple months ago the "Stock" motor "crapped" out and I have been looking for a replacement. I did not necessarily want to use the "Stock" prop and Spinner (can't seem to find in my messy shop anyways). I do have a spinner and that should work but I was limited to a motor with a 4 mm shaft. I would find a 28 mm motor that would fit nicely but the shaft was not 4 mm. To shorten a long story .... I have a Radian and thought perhaps the motor from that might fit....the shaft is 4 mm, so my spinner and prop will work . So I removed it from the Radian to find it was a little larger in diameter. Not discouraged though. I took a Dremmel with a sanding drum on it and removed the inner plastic in the noes area. the motor fits just right and we will see how it performs. the Prop for now will be an Aeronaut 9 X 5 because that's what I have, if this setup works, I can go to something that will give a little more thrust. I have a CC Thunderbird 36 ESC, so as long as motor can take it.... Here are some pics of the modification. Not sure when I will get a chance to test it out, it's winter here in Pennsylvania
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Old Jan 13, 2013, 08:36 AM
I have Imajinary Airplanes
7 Miles from Turkey Hill Slope, PA.
Joined Mar 2003
656 Posts
Well, this AM I had a chance to finish up. I tested in shop with 9X5 prop and felt it was too little thrust, only drawing 9 amps. Found a set of 10X7 blades and that draws 20 amps with of course more thrust. Only added 1/2 oz of lead to tail. A bit foggy right now but will test out in a little bit.

Dave
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Old Jan 13, 2013, 09:45 AM
I have Imajinary Airplanes
7 Miles from Turkey Hill Slope, PA.
Joined Mar 2003
656 Posts
So, the Fog just is not lifting, so I ventured out to give it a go. (see pic of fog). The decision to increase prop size was a good one as the climb is authoratative but not straight up! I only had 150 feet of ceiling(at most) and maybe less. The bottom line is that this seems to be a "doable" replacement for this plane. If it turns out differently I will post.
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Old Jan 21, 2013, 06:28 AM
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yorkshire UK
Joined Oct 2007
3,732 Posts
I have a parkzone 960kv sitting in my spares box, so if mine goes up I know what to do then!
Looks a tight fit though! But I bet it does not get hot like original! I got a set of 10 * 8 blades too!
Need to check tail too as never found a problem iwth mine apart from not being level with wings, mind you the wings are warped a bit anyway! Still flies nice though.
I wil fly this more soon when weather is better and ground is not muddy, for now I am loving my blaster dlg as that cleans up easy and can be caught by hand so often does not even get muddy!
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Old Jan 21, 2013, 06:48 AM
I have Imajinary Airplanes
7 Miles from Turkey Hill Slope, PA.
Joined Mar 2003
656 Posts
I was able to get out one more time since the first Sunday test. The ceiling was still a bit low but the climb is pretty nice compared to stock. The replacement motor for Radian should arrive tomorrow.

Dave
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Old Feb 01, 2013, 05:11 AM
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Australia, NSW, Sydney
Joined Aug 2006
6,905 Posts
Hi Guys. A friend and I bought one each to fly at an event we go to each year.
Thought I would post the mods I had to do over the week in here.

First up, the motor mount grub screws had not been tightened at the factory and the motor pulled out a couple of minutes into the first flight killing it.

I swapped it out for a motor from an ST Models blaze (had to modify the mount because it has a non reversible shaft and i had to fit it the other way. It climbs vertically now

I added a 3x1 carbon spar to the tail to stiffen it a little. it did the job. A balsa elevator would be better.

I chopped out some foam and fitted a balsa plate to the bottom of the tail where it mounts to the h-stab. I pulled out the plastic at the top of the h-stab )it was sloppy from the factory) and glued it in properly with epoxy. It's fairly solid now.

The encapsulated nuts for the wing mounts were both loose and needed to be re-glued.

I swapped the elevator servo for an mg-14 from Hobbyking. works a treat.
The wing servos strip easily. I'll be swapping them out too when they strip again.

I'm thinking about replacing the ailerons with balsa which would improve the roll authority a lot.

We put some fibre tape on the leading edges and under the fuse at the front to protect on landings.

All said and done, this plane is one of the best $150 I've ever spent. it's great. We flew them more than any other plane on the trip in all sorts of conditions from nil wind to over 25kn on the slope. They thermal well and fly great as long as you keep them moving. They are fast for a foamie and look pretty good in the air for what they are.

Cheers,
Mick
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Old Feb 04, 2013, 02:34 AM
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yorkshire UK
Joined Oct 2007
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Quote:
Originally Posted by me_wantee View Post
Hi Guys. A friend and I bought one each to fly at an event we go to each year.
Thought I would post the mods I had to do over the week in here.

First up, the motor mount grub screws had not been tightened at the factory and the motor pulled out a couple of minutes into the first flight killing it.

I swapped it out for a motor from an ST Models blaze (had to modify the mount because it has a non reversible shaft and i had to fit it the other way. It climbs vertically now

I added a 3x1 carbon spar to the tail to stiffen it a little. it did the job. A balsa elevator would be better.

I chopped out some foam and fitted a balsa plate to the bottom of the tail where it mounts to the h-stab. I pulled out the plastic at the top of the h-stab )it was sloppy from the factory) and glued it in properly with epoxy. It's fairly solid now.

The encapsulated nuts for the wing mounts were both loose and needed to be re-glued.

I swapped the elevator servo for an mg-14 from Hobbyking. works a treat.
The wing servos strip easily. I'll be swapping them out too when they strip again.

I'm thinking about replacing the ailerons with balsa which would improve the roll authority a lot.

We put some fibre tape on the leading edges and under the fuse at the front to protect on landings.

All said and done, this plane is one of the best $150 I've ever spent. it's great. We flew them more than any other plane on the trip in all sorts of conditions from nil wind to over 25kn on the slope. They thermal well and fly great as long as you keep them moving. They are fast for a foamie and look pretty good in the air for what they are.

Cheers,
Mick
Sounds like you covered all the problems right there in that one post lol. She does look very nice and flies well at speed, I only ever had a handful of thermal flights though, the longest being about 10 mins(total 26 min flight) but I tent to just do tricks with this bird as I have others which thermal much better, ie the st asw28 and the hk minimoa and in a league of it's own the dlg blaster which will thermal on a sheeps fart, but for impressive speed and looks this one wins hands down.
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