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Old Nov 17, 2007, 07:21 PM
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New Bern, North Carolina, United States
Joined Oct 2004
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Mini-Review
HL SU-27 Russian Knight Maiden/MOD'S!!!!!

OK, the maiden happens tomorrow morning but this is the first part of my mini-review:

I bought the ARF kit.

The foam appears as the standard issue type, so foam safe CA is required. During the build I used Foam safe CA instead of the screws for the horz and vert stabs and it place of the provided glue on the main wings. Build takes about 25 minutes.



Things to pay attention to:

1) Hand work the elevators... ALOT.. the plastic coating on the stabs makes them very stiff, they will stress the crap out of the stock servo (actually any servo for that matter)

2) Open up the battery area going towards the tail....so you can get a real lipo in there

3) GET A REAL LIPO!!! ( the stock lipo is a 10c lipo...thats not going to cut it on duel BL motors and 64mm EDF's... use at least a 15C... the ESC is 30 amp so get a lipo that will support at least 30 amp contin.)

4) Ensure that when you mount the servo horns for the elevators that they are both on the same side of the servos (ie...1 horn should she between the servo and the duct, the other servo horn should be on the outside of the servo and the wing tip, failure to do this will result in the control surfaces going opposite directions)

5) CHANGE out the FAKE DEANS, I have had these before and they suck... fragile, a PITA to connect, a PITA to seperate...and they are just slightly different that a real DEANS wont connect without a lot of fighting.

6) Glue the rudders on... the screws are not enough to ensure they stay put... dont risk it....

Mine is ready to go so tomorrow I will have her at the field for the maiden...
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Last edited by ATIS; Dec 26, 2007 at 06:53 PM.
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Old Nov 17, 2007, 07:55 PM
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Dennis H.'s Avatar
Denton Tx.
Joined Sep 2003
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Hi ATIS, Where did you see the li-po is a 10c?
I look over my, could not find that info.

Do you know where the C/G suppose to be?
Dennis
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Last edited by Dennis H.; Nov 17, 2007 at 08:04 PM.
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Old Nov 17, 2007, 09:20 PM
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Upstate NY
Joined Jun 2007
4,782 Posts
Good luck! I had the brushed one as my first plane and that was a bad move, couldn't even get it in the air! I'm curious to see how this thing will fly. Its too big to hand launch so you really need a runway.
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Old Nov 17, 2007, 09:30 PM
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Hi metroidrc, I'm not new to r/c, but I am new to duct fan jets! My field is grass, I don't think it will get off the ground, Going to my friend house in the morning and use the street Lol... Wish I had a video camera, But I will take photo before she goes up
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Old Nov 17, 2007, 09:59 PM
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USA, GA, Savannah
Joined Nov 2005
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I look forward to a first flight as well Just recieved the su-27. As ATIS says the stabs need to be CA'd, the screws won't be enough alone. I opened up the batt tray to take EVO 25C 2170's and the CG is good. From what I read the stock lipo is not going to be good power.
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Old Nov 17, 2007, 10:09 PM
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Steve, let us know how your flight went too. I find some video at youtube, They seem to fly good, two of them, the people hand launch them, one almost didn't make it, the other, I think he upgrade the motor, Boy it was fast
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Old Nov 17, 2007, 10:23 PM
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USA, GA, Savannah
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Got a link to the youtube videos? I think the stock motors will get upgraded as well as servos, this plane is nice but stock elec is marginal imho. esc seems good though.
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Old Nov 17, 2007, 11:00 PM
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Fort Collins, CO.
Joined Sep 2002
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bryan, cant wait to see her fly, hope the wind stays low early. I will be there for sure, around 8am. good luck, scott.

of course I did not get my f-18, so I dont know whats up with that.... sucks.
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Old Nov 18, 2007, 06:40 AM
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New Bern, North Carolina, United States
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Scott... 8am!! I am on my way once I finish typing (its 6:30 now)...

Dennis read the warning onthe side of the lipo... states "do not discharge at more then 10c for any length of time".... that leads me to believe she is a 10c with aybe a 15c burst.... weak...
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Old Nov 18, 2007, 08:56 AM
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Steve, I just type in RC SU-27 and found them.

ATIS, You are right about the Li-po, My eyes are not as good as they use to be Lol...
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Old Nov 18, 2007, 12:28 PM
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New Bern, North Carolina, United States
Joined Oct 2004
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Maiden Report

Weather:
Calm (dead calm)
Sunny
Clear Blue Sky's

yeap, the perfect morning to fly

So I set her up and forgot to hook up the nose servo... didnt matter not enough power to ROG (grass) could get her to move on the grass (1 inch long) so you guessed it... hand launch time!!

So with a good friend and flying buddy doing the hand launch (he hand launches my F-15, F-16 and A-10 for me along with any other belly floppers on their maidens so he's an expert) I run her up to WOT and Tommy gives her a nice two step and hard level throw... she goes nose high and I am giving all the down elevator she has ... climbs nose high to 15 feet and stalls, starts a tail slide and then noses over.... I quickly try and level her but she is dead and the nose drops towards the deck so I chop the throttle and pull back hard trying to ge the nose to at least come up. I manage to prevent a nose in but she still hit hard, broke her in two piece (three if you count the nose cone coming off as well) ...so needless to say the maiden was 10 seconds long and less then impressive.

Under powered for hand launchs... period... I can comment on a ROG but I would recommend a CG change... someoen stated the CG is on the servo wire covers... I set mine to the center of them... move the CG to the leading edge of those covers... t may have helped prevent the nose up stall.

As any good poster here knows, you gotta have the before and after shots, so here ya go... enjoy them. I plan to make a few mods like opeing up the battery area, getting rid of the battery hatch (not too hard since its hanging off anyways) and maybe a nice motor upgrade....

FlyBye (scott) can attest, I did everything to save her...
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Old Nov 18, 2007, 12:49 PM
Targeted and... FIRING !
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United States, MI, Eastpointe
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ouch.
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Old Nov 18, 2007, 01:12 PM
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Upstate NY
Joined Jun 2007
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Atis,
I'm sorry for your woes.. I had the same thing with my Su-27. Its just too big for a hand launch. I tried it and it went straight into the ground. It needs a long runway for takeoff. In fact the brushed version I couldn't even get to take off with 150 feet of runway! I tried to even get a refund from Hobby Lobby because I was so upset about it, but they wouldn't do it for me. My friend and I both bought Su-27's and both planes ended up in the garbage. Of course, this was our first plane. Once again, I'm sorry for your loss. Are you going to try to repair? Or are you done with it?
-Josh
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Old Nov 18, 2007, 02:14 PM
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New Bern, North Carolina, United States
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repairs underway...

1) opened the battery area up to make it easier to get a real lipo in her...threw out the battery hatch...

2) nose is epoxied on... drying as I type...


Now I did a little measuring... the outlet ducts are 56mm left and 55mm on the right...not a big difference but I have to do the math... 85% of the duct area is optimized for speed and less then that is thrust, so now I have to break out the 5th grade math and see what this comes out to... this plane needs the thrust more then speed to get her moving but we will see... any thoughts on that issue??
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Old Nov 18, 2007, 02:19 PM
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New Bern, North Carolina, United States
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ok, I am smarter then a 5th grader... that works out to 85% of the duct diameter... I wonder if opening it up a few mm would help it out, top end would suffer but it may get off the deck easier/faster...

Whats the KV of the stock motors?? I just put her on the Watts Up Meter with the following results: 18.5 amps and 197 watts (total at WOT both motors) thats 9 amps and 98.5 watts each... time to upgrade the motors... my Razor 400's in my A-10 (55edf) put out more then that...100 watts per pound is the starting for mild 3d and to get real 3d you need 150 watts... EDF are not as effiecient but if you want jet performance you need to at least get to 150 watts per pound. (mine weighs 1.8 pounds) yes she is not 3d I know that but she needs at least enough power to get out of her own way... shame on you HL, thats not stock in the video...


repairs completed... ready to fly but figuring out what motors to replace the stock with... maybe a nice EFLite 400 (3700kv) inrunner with a max amp pull of 20 amps... watts will be 200 so that would be 400 watts total, double the current set up... not sure what she will pull on the fans with 6 blades....
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Last edited by ATIS; Nov 18, 2007 at 03:52 PM.
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