HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Mar 15, 2011, 08:50 PM
Disney Martins
yensidsnitram's Avatar
Brasil, PB, Pombal
Joined Apr 2010
36 Posts
Hi guys!
I'm Brazilian and I've just set up an SU-47 Berkut by Banana Hobby. I am accompanied this post to make adjustments before the first flight.
I also had great difficulty in adjusting to cover the landing gear, especially the nose gear, but I guess I did ...
Here are some pictures:




This is my first EDF airplane!!!

Here the video of the endurance test of the landing gear. Our track is bad, just dirt!

SU-47 Berkut - Teste de resistência do trem de pouso (3 min 35 sec)


And here I found the solution to the port of landing the nose gear...

SU-47 Berkut by Banana Hobby - Ajuste da tampa da bequilha (2 min 16 sec)
yensidsnitram is offline Find More Posts by yensidsnitram
Reply With Quote
Sign up now
to remove ads between posts
Old Mar 15, 2011, 09:02 PM
Why kamikaze pilot wear helmet
mikes68charger's Avatar
United States, OH, Columbus
Joined Jul 2010
1,097 Posts
Can you show a pic of how you fixed the nose gear?

Thanks Mike
mikes68charger is offline Find More Posts by mikes68charger
Reply With Quote
Old Mar 16, 2011, 04:49 PM
Registered User
Mtn_Commando's Avatar
United States, CA, Dublin
Joined Sep 2008
1,009 Posts
Quote:
Originally Posted by yensidsnitram View Post
Hi guys!
I'm Brazilian and I've just set up an SU-47 Berkut by Banana Hobby. I am accompanied this post to make adjustments before the first flight.
I also had great difficulty in adjusting to cover the landing gear, especially the nose gear, but I guess I did ...
Here are some pictures:




This is my first EDF airplane!!!

Here the video of the endurance test of the landing gear. Our track is bad, just dirt!


And here I found the solution to the port of landing the nose gear...
Nice underside artwork.

The biggest trouble with foamies is that they are so damn fragile.

Good job with the landing gear doors. I wrestled with them forever and still couldn't get them to work properly.

Let us know how you maiden goes, perhaps post a video.

The weather is warm enough now. Time for me to dig mine out and get it back in the air.
Mtn_Commando is offline Find More Posts by Mtn_Commando
Reply With Quote
Old Mar 16, 2011, 11:00 PM
Registered User
Canada, AB, Calgary
Joined Oct 2010
333 Posts
Quote:
Originally Posted by Mtn_Commando View Post
Nice underside artwork.
The biggest trouble with foamies is that they are so damn fragile.
A man walks on the road and sees car crashed into a concrete wall. There's a bleeding driver on the ground nearby who mumbles:
- Thanks Lord that by half, thanks Lord that by half...
- Excuse me, what do you mean by "by half"?
- mv^2 by half.

I remember this each time I crash my foamie and think how it looked like if plane was 4kg instead of 2.
Sockrat is offline Find More Posts by Sockrat
Reply With Quote
Old Mar 17, 2011, 04:43 AM
Disney Martins
yensidsnitram's Avatar
Brasil, PB, Pombal
Joined Apr 2010
36 Posts
All right Mtn_Commando

I am working to reinforce the mounting location of the landing gear and put fiberglass stringers in the wings.

When making new attempts to fly, taped and video, and the report of the results.

Hugs
Disney
yensidsnitram is offline Find More Posts by yensidsnitram
Reply With Quote
Old Mar 17, 2011, 10:30 AM
Why kamikaze pilot wear helmet
mikes68charger's Avatar
United States, OH, Columbus
Joined Jul 2010
1,097 Posts
my plan for strenthing the retract pad was to eather fiberglass, or use carbonfiber rope, and make a good strong base. I was then thinking of adding a peace of very thin ply to the other side and running 2 or 3 screws throw the plastic retrac base throw the fiberglass/foam to the wood. do you think this is to much?
mikes68charger is offline Find More Posts by mikes68charger
Reply With Quote
Old Mar 17, 2011, 12:59 PM
Disney Martins
yensidsnitram's Avatar
Brasil, PB, Pombal
Joined Apr 2010
36 Posts
Quote:
Originally Posted by mikes68charger View Post
my plan for strenthing the retract pad was to eather fiberglass, or use carbonfiber rope, and make a good strong base. I was then thinking of adding a peace of very thin ply to the other side and running 2 or 3 screws throw the plastic retrac base throw the fiberglass/foam to the wood. do you think this is to much?
Would not adding too much weight?

I'm pasting a wooden lite ply base on it will stick the landing gear which will then be secured with four screws.

I'm shooting and then post the pictures here ...
yensidsnitram is offline Find More Posts by yensidsnitram
Reply With Quote
Old Mar 17, 2011, 01:22 PM
Why kamikaze pilot wear helmet
mikes68charger's Avatar
United States, OH, Columbus
Joined Jul 2010
1,097 Posts
Quote:
Originally Posted by yensidsnitram View Post
Would not adding too much weight?

I'm pasting a wooden lite ply base on it will stick the landing gear which will then be secured with four screws.

I'm shooting and then post the pictures here ...
So your saying your makeing a lite ply base that will fill the bottom of the hole, then glueing and screwing the retract to the wooden base?

That sounds good, that way there is a wider foot print for the retract.

I have not flown this bird yet so any real world results are greatly appreceated.

Iron Mike
mikes68charger is offline Find More Posts by mikes68charger
Reply With Quote
Old Mar 17, 2011, 03:14 PM
Registered User
hklagges's Avatar
Munich
Joined Dec 2008
1,158 Posts
Quote:
Originally Posted by yensidsnitram View Post
I'm pasting a wooden lite ply base on it will stick the landing gear which will then be secured with four screws.
If I may give a bit of unsolicited advice: Don't do that. The Su-47 is really fast. Avoid to make it heavier if you can - really really. And if the landing gear came out on a tough landing that was because some ahem worker at the factory did not use enough glue or was instructed to economize on glue. If you properly epoxy in the landing gear, you will not need wood or anything.

A lot of force can be transmitted over the gear surface as it is. If you strenghten that so that it won't break, it will break next to the rim of your strengthening pad.

Just my opinion, ofc :-).

Cheers,
Henrik
hklagges is offline Find More Posts by hklagges
Reply With Quote
Old Mar 17, 2011, 10:55 PM
Why kamikaze pilot wear helmet
mikes68charger's Avatar
United States, OH, Columbus
Joined Jul 2010
1,097 Posts
So I can judge my progress what is your total weight? Thanks for the advice
mikes68charger is offline Find More Posts by mikes68charger
Reply With Quote
Old Mar 18, 2011, 12:33 AM
A Global Force For Good
jmpdgs's Avatar
USA, OH, Cincinnati
Joined Jun 2009
730 Posts
I respectfully disagree with Henrik on this issue. This and almost all of the LX models require extensive gear housing rework. Even the stock AC is easily able to handle an additional 60 grams of weight distributed over the three gear bases. I see no value in flying fast if when you touch down you rip the gear out of the housing.

Two hour of work during the initial build saves many hours of tedious repair when the eventual failure happens, and it absolutely will happen, if not today, all too soon.

Save the weight where and when you can on non-essential systems but NEVER skimp on the important stuff.

Cheers and happy flying.
Joe
jmpdgs is offline Find More Posts by jmpdgs
Reply With Quote
Old Mar 18, 2011, 04:22 PM
Registered User
Canada, AB, Calgary
Joined Oct 2010
333 Posts
My view on the LX landing gear is it can handle very strong vertical impacts, strong front impacts and barely any side hits. This is especially bad for dual-wheel front gear which can hit a stone with just 1 wheel. If you steer sharp at high speed or land at crosswinds there's a good chance to strip gear off like on the video above. How epoxy binds to flexible plastic surfaces we all know... Therefore adding some side support rods or plywood on the back side might be essential.

I badly crashed my 1m AMX jet twice due to landing gear detaching seconds before takeoff - it's unrecoverable when your plane takes off and spins.
Sockrat is offline Find More Posts by Sockrat
Reply With Quote
Old Mar 22, 2011, 05:06 AM
Disney Martins
yensidsnitram's Avatar
Brasil, PB, Pombal
Joined Apr 2010
36 Posts
Berkut = 12 sec flying!!!

Good morning fellow model airplane! (06:04 AM)
I need your help. I was flying my Berkut this weekend but the result was not very good. I'm putting the video for you to analyze and to tell me what is wrong.
The CG is at 30mm.

Primeiro Vôo do Berkut SU-47 (0 min 45 sec)


I'm working to recover the aircraft.
Disney
yensidsnitram is offline Find More Posts by yensidsnitram
Reply With Quote
Old Mar 22, 2011, 10:15 AM
Registered User
hklagges's Avatar
Munich
Joined Dec 2008
1,158 Posts
Hello Disney,
Quote:
Originally Posted by yensidsnitram View Post
I'm putting the video for you to analyze and to tell me what is wrong.
thanks for sharing the video so that we can analyze it. My take (as a person who has built and flown this aircraft and who is still scared by it) is:
  • Your start is pretty good. Not much veering left or right while on the ground.
  • After takeoff, you give or sustain a bit much up-elevator. With so many control surfaces and the tv all giving elevator effect, it is very easy to do so on this model!
  • You have much up-elevator, but it is not really bad. Interesting is your reaction. At about 17 seconds into the video, you give a bit of down elevator to correct the fast rise, which is ok (you could have left it going on rising at that angle, too). But you also reduce the throttle by a lot, which is not good. This airplane has to be flown fast or it won't fly!
  • At about 0:18, you pitch up A LOT. Why? Was that a control input by you? That is overcontrolling.
  • To recover from the pitching up, you reduce throttle at 0:19 - not good again. The plane stops rising and falls over the wing side.
  • You are rather lucky that the plane doesn't fall a lot, but settles into its "my happy ass" mode. That is when it drops the tail and crouches along with a way too high angle of attack.
  • At 0:23 you do the right thing to recover from this uncomfortable situation: You power it up! Good.
  • The plane seems to pick up some speed, lower the angle of attack and recover a bit (0:25). It looks as if you are well on your way to exit from the drop-my-tail situation.
  • But at about 0:27, you cut power again - why? The plane was way too slow. It needed power. And it was in a reasonably level flight situation. All you had to do was keep the power going.
  • You seem to realize this and reapply power while the plane already loses altitude fast and is in a steep right turn. The situation is critical, because the plane is so close to the ground.
  • Then, either you did not try to correct against the right turn or it stalls over the right wing.

So the biggest news is: Power the beast UP. Don't fly it at 50% throttle. Fly it at 75%, or maybe a bit less when it is already fast and flying level.

And the next news is: This plane is easily overcontrolled. So dial in expo or change the mechanical links to the elevators and canards to a position where the control surfaces deflect less for a given servo input.

Cheers,
Henrik

PS: I don't think the CG was particularly bad. With power, it should have flown, with the occasional time spent in drop-my-tail-mode.
hklagges is offline Find More Posts by hklagges
Last edited by hklagges; Mar 22, 2011 at 01:04 PM.
Reply With Quote
Old Mar 22, 2011, 10:49 AM
Registered User
Mtn_Commando's Avatar
United States, CA, Dublin
Joined Sep 2008
1,009 Posts
Quote:
Originally Posted by yensidsnitram View Post
Good morning fellow model airplane! (06:04 AM)
I need your help. I was flying my Berkut this weekend but the result was not very good. I'm putting the video for you to analyze and to tell me what is wrong.
The CG is at 30mm.


I'm working to recover the aircraft.
Disney
Did you reduce the throttle, or was there a problem with the power system? You CANNOT slow this plane down. It needs lots of speed, at all times. Remember that and you will be fine. And reduce throws a little. So i concur with Henrik's advice.

CG looks ok. Damage doesn't look bad. Good luck with the next flight.
Mtn_Commando is offline Find More Posts by Mtn_Commando
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
New Product FreeWing 70mm F-35 w/ Thrust Vectoring bhatch21 Foamy EDFs 1424 Oct 12, 2014 08:45 AM
Discussion F-22 Raptor thrust vectoring scratch built twin ducted fan jet MikeysRC Foamies (Scratchbuilt) 2 Aug 05, 2009 12:29 PM
Discussion SU-35 or any twin EDF with thrust vectoring dash8pilot Electric Ducted Fan Jet Talk 11 Jul 21, 2008 08:32 AM
Discussion Wicked thrust vectoring twin turbine mig-29 video lavochkin Foamy EDFs 5 Jun 12, 2008 01:07 PM
Build Log Mig-35 Twin EDF w/ Thrust Vectoring tailslide5_0 Foamy EDFs 23 Aug 27, 2007 10:20 PM