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View Poll Results: Which livery do you like most?
Travel Service (blue) 9 19.57%
Travel Service (white) 4 8.70%
Czech Airlines (new c/s) 15 32.61%
Holidays Czech Airlines 11 23.91%
Czech Airlines (old c/s) 7 15.22%
Voters: 46. You may not vote on this poll

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Old Aug 07, 2014, 03:30 PM
Doushiyou12's Avatar
Joined Feb 2010
1,690 Posts
Sorry to hear the results.
You did a fantastic job on this build. Keep your head up and I hope to see another build soon.
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Old Aug 07, 2014, 03:54 PM
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Charelston SC U.S.A.
Joined Mar 2007
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I'm sorry indeed my brother. . . . It's times like this people see how hard this hobby truly is. . . I hope you build another A320.

Please build 2 planes next time.. . . . . Your a great builder! And your new A320 will rise from the tarmac!
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Old Aug 08, 2014, 02:51 PM
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Charelston SC U.S.A.
Joined Mar 2007
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One trick I have learned to keep fan blade hub on the motor shift is the use of "thread-lock". . . I had the same problem happen to me with my Big-Bunny DC-9-30. . . I had a rotor hub fly off of my very 1st takeoff attempt. . .after that I applied thread-lock and applied it to all my fan units and never had that problem again.

Only problem now is I can't get the blade hub off the shift when I need to.
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Old Aug 10, 2014, 07:27 AM
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Quote:
Originally Posted by demondriver View Post
One trick I have learned to keep fan blade hub on the motor shift is the use of "thread-lock"
Like you glue the rotor directly to the shaft, or you secure the screw thread and the "hat" with it?
On the V-15, I mean this:
http://www.e-fliterc.com/ProdInfo/EF...LDF152-250.jpg
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Old Aug 10, 2014, 10:56 PM
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Charelston SC U.S.A.
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Quote:
Originally Posted by awacsCZE View Post
Like you glue the rotor directly to the shaft, or you secure the screw thread and the "hat" with it?
On the V-15, I mean this:
http://www.e-fliterc.com/ProdInfo/EF...LDF152-250.jpg
Yes . . Thread-lock is a material that has the same thickness & consistency as milk. . . .you brush it on with a thin coat over the motor shaft then add the collet adapter.
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Old Aug 11, 2014, 04:51 PM
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Quote:
Originally Posted by demondriver View Post
Yes . . Thread-lock is a material that has the same thickness & consistency as milk. . . .you brush it on with a thin coat over the motor shaft then add the collet adapter.
And is there any issue with balancing, or is it ok? Anyway, how bad is it to pull it down after that?

Meantime, I finally got images of the aftermath Check your blades, guys, check your blades
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Old Aug 11, 2014, 05:41 PM
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Originally Posted by awacsCZE View Post
And is there any issue with balancing, or is it ok? Anyway, how bad is it to pull it down after that?

Meantime, I finally got images of the aftermath Check your blades, guys, check your blades
adding thread lock to the motor shall will not interfere with balancing because the shaft is at the very center of the edf itself.

CZE all you need to do is build another forward half of your A320's fuselage . . And do some repair work on your right wingtip.

I've repaired worse Sir.
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Old Aug 11, 2014, 05:50 PM
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Quote:
Originally Posted by demondriver View Post
adding thread lock to the motor shall will not interfere with balancing because the shaft is at the very center of the edf itself.

CZE all you need to do is build another forward half of your A320's fuselage . . And do some repair work on your right wingtip.

I've repaired worse Sir.
ok, thank you.

About repairing. I donīt know, I think to build it again and lighter and better with help of the laser would do better job. I am also affraid of some structural damage, that can be hidden inside and will show maybe at the 2nd flight, or more, slowly growing and some flight would be fatal too. It is not in clear view from the photos, but elevator seems to be broken inside under the balsa cover.

I would not have trust in that repaired thing to fly it.
Better safe than sorry again

P.S.: I think, that was the robust, heavy build, which caused to be in this condition
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Old Aug 11, 2014, 06:01 PM
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Originally Posted by awacsCZE View Post
ok, thank you.

About repairing. I donīt know, I think to build it again and lighter and better with help of the laser would do better job. I am also affraid of some structural damage, that can be hidden inside and will show maybe at the 2nd flight, or more, slowly growing and some flight would be fatal too. It is not in clear view from the photos, but elevator seems to be broken inside under the balsa cover.

I would not have trust in that repaired thing to fly it.
Better safe than sorry again

P.S.: I think, that was the robust, heavy build, which caused to be in this condition
Sir Are you saying your A320 crashed because it was too heavy? Or because a rotor hub came off?
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Old Aug 12, 2014, 01:07 AM
This is a fine fiddly business
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United States, WA, Marysville
Joined May 2009
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CZE,
You did a beautiful job on the build. I am very sorry for the loss of a lovely plane.

I think you are correct about several things:

1. The immediate cause of the crash was losing one engine. You will certainly check the propeller, fan assembly as a permanent part of your pre-flight check list. DD's suggestion of the non-permanent thread lock is a good thought. Avoid the permanent thread lock.
2. Weight is your mortal enemy. Around the time of your first attempted flight, I tried to calculate your wing loading. The calculated stall speed was quite high as I recall.
I think your idea of rebuilding but much lighter is sound. Wing cubic loading formulas could give you an estimate of a weight goal.

Calculate the wing cube loading for the full size airplane and aim for the same wing cube loading for your model. One reference below.

http://www.rcgroups.com/forums/showthread.php?t=604935

In the old free flight days there were very frequent crashes. Builders would look at their crashed models and say, "Every thing that didn't break in the crash should be build lighter in the next plane." Not a bad idea.

Another idea that might help would be to incorporate fixed flaps and slats. If they were fixed you would save a lot of weight on servos wire and linkages and still have increased lift and wing area. The down side is you always have to fly in landing configuration. Jeff of the Nefwaffe channel has done that to good effect.
AA Super 80 & USAir 757 (4 min 38 sec)


Best and condolences,
Robert
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Old Aug 12, 2014, 03:44 AM
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Russian Federation, Mosk. oblast', Grigorchikovo
Joined Jul 2005
352 Posts
It is a pity to hear such news.
I hope you will build one more A320, it is better and lighter than this. Good luck and new progress.
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Old Aug 12, 2014, 03:47 AM
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Quote:
Originally Posted by demondriver View Post
Sir Are you saying your A320 crashed because it was too heavy? Or because a rotor hub came off?
I probably wrote that in bad way. I meant that many parts survived because I made it heavy and robust
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Old Aug 12, 2014, 05:40 AM
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Quote:
Originally Posted by Robert R View Post
CZE,
You did a beautiful job on the build. I am very sorry for the loss of a lovely plane.

I think you are correct about several things:

1. The immediate cause of the crash was losing one engine. You will certainly check the propeller, fan assembly as a permanent part of your pre-flight check list. DD's suggestion of the non-permanent thread lock is a good thought. Avoid the permanent thread lock.
2. Weight is your mortal enemy. Around the time of your first attempted flight, I tried to calculate your wing loading. The calculated stall speed was quite high as I recall.
I think your idea of rebuilding but much lighter is sound. Wing cubic loading formulas could give you an estimate of a weight goal.

Calculate the wing cube loading for the full size airplane and aim for the same wing cube loading for your model. One reference below.

http://www.rcgroups.com/forums/showthread.php?t=604935

In the old free flight days there were very frequent crashes. Builders would look at their crashed models and say, "Every thing that didn't break in the crash should be build lighter in the next plane." Not a bad idea.

Another idea that might help would be to incorporate fixed flaps and slats. If they were fixed you would save a lot of weight on servos wire and linkages and still have increased lift and wing area. The down side is you always have to fly in landing configuration. Jeff of the Nefwaffe channel has done that to good effect. https://www.youtube.com/watch?v=Efmk...8ffI0yDMrg4c5A

Best and condolences,
Robert
Yes, I will definitely try tu build it lighter, but I think building it much lighter wouldnīt be good idea, because of the strength of the airframe. I dontīt want to rebiuld it after every harder lading :-D

Goals for me for 2nd A320 are:

1) lighter - I think cut down 500-700g would be maybe possible. Because of the laser I will have to use balsa rubs in the fuse, but it will by light 2mm balsa, so it wont be big harm. I will keep three wing ribs which bear the engines in plywood 2mm, also light, but all other ribs will be from light balsa too (2-3mm). But the mos possible improvement will be in coating, which I will do from light or super light balsa, not from standard

2) Better wing angle - I did accidentaly smaller angle, which could cause unstability in turns, so goal is bigger angle.

3) Maybe better landing gear with some spring to deal with harder landings.

About flaps, well I followed the plan and they are not there. I donīt trust myself enough to do this. I donīt even know how to determine that Friend of mine encouraged me for moving flaps, but I donīt know, maybe, but I think it can be flown without them I tried faster flying with my T-34 and it was fine, I think if it will be right, it will fly good as the other builders report

Thank you very much for advices, I will try my best to do it better and right this time.
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Old Aug 13, 2014, 04:07 PM
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Charelston SC U.S.A.
Joined Mar 2007
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Quote:
Originally Posted by awacsCZE View Post
I probably wrote that in bad way. I meant that many parts survived because I made it heavy and robust
I'm sorry I misunderstood you Sir.
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