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Old Apr 25, 2010, 03:17 PM
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Munich
Joined Dec 2008
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Flight Report

Hello there,

here some more data from a test flight. The setup I tried was:
  • Center of gravity 10mm further to the rear than given by the factory
  • Default trim of all control surfaces neutral
  • Default horizontal trim of the vector nozzles slightly "up", i.e., like up-elevator, by a few degrees
This was with a heavy plane configuration (AUW = 2,69kg). I had a new lipo battery, an SLS EP 4000mAh 6S1P. I bought it a) because it fits the battery compartment very well, being 45mm wide and b) because of quality. Out of my three brand-new Turnigys, the first went bad during the test run in my living room and the second during its first usage in flight. So I am sick of HobbyKiller batteries for a while. In addition to the 634 grams of the main lipo I had a 77 gram receiver battery. I put this receiver battery into the lower part of the fuselage head (you have to clean out the foam "ribs" a bit), otherwise, the CoG would have been terrible.

The results where:
  • The plane appeared slightly tail-heavy. It was unclear whether this was from the CoG or from the slight "up"-angle of the tv nozzles.
  • Gliding with low-engine rpm seemed acceptable.
  • Man, this is fast. I am wondering whether to deploy the brake parachute.
  • The front gear ripped out completely, even though it was epoxied in. We could use larger wheels, but they don't fit the gear compartment well.

So the next flight will be with a slightly reduced "up" angle of the tv nozzles, maybe even neutral angle. I am reluctant to go all towards neutral because in the Su-34, 2 of up angle seemed to do well, and also I don't want to return to the state where the default trim will be with significant canard up trim.

One important tip: The servo connection rods / clamps seem bad quality. The pin in one of the clamps simply broke off. This means that we might have to redo all rods & clamps with higher quality gear - a lot of work.

Cheers,
Henrik
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Last edited by hklagges; Apr 25, 2010 at 04:45 PM. Reason: Typo fix, AUW.
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Old Apr 25, 2010, 03:53 PM
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San Diego
Joined Jul 2002
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Quote:
Originally Posted by Mtn_Commando View Post
good job. too bad you're selling it. i would suggest advertising on rcgroups, rcuniverse, and craigslist (I'm assuming it will be local pickup only?). how much are you going to list it for?
Thank you Mtn Commando. Yes, local pick up. It already sold. I listed for $350 and sold it for $325. I have a kind of sellers remorse as it was ready to fly and the twin motors sounded really cool. But now I can move onto my Dauntless and have some money for servos. Good luck to all SU47 flyers! They are great looking planes. I hope someone makes a composite version someday.
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Old Apr 25, 2010, 04:45 PM
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Duduca's Avatar
Brazil, MG, Ipatinga
Joined Jan 2010
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Did any of you fly the eurofighter 90mm ?
What are my options as far as batteries for this model. Do any of you think the blue lipo will work with this jet ?
Does it have to fly on 30c or a 20c,25, or even 40c would do it ?
i have not done any modification to the jet yet. The only thing is that i bought the DX7 and a spectrun receiver for this model.
I would like to fly this model on a battery that my blue lipo charger would charge.
any recommendations ? Thanks in advance.
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Old Apr 25, 2010, 07:01 PM
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Munich
Joined Dec 2008
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Hello Duduca,

the EF's ESC is rated at 85A. Suppose you have 3,6AH battery. That means 20 won't work, 25 will be very optimistic. I guess 30c is minimum. And if you look at what the retailers package with the Eurofighter, e.g. ready2fly packages 35C packs, you might consider those, too.

With the EF I would make sure that you get the upgraded units, not one of the first batch that had all the servo, wire and gear faults.

Cheers,
Henrik
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Old Apr 25, 2010, 07:12 PM
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United States, CA, Dublin
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Quote:
Originally Posted by hklagges View Post
This was with a heavy plane configuration (AUW = 2,69kg)
This is great to know that she can take so much weight, thanks. I'll be somewhere in that region too.
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Old Apr 25, 2010, 08:05 PM
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I installed the new MB1's and Castle 100A ice. They really screams with the 5s 5800mah Zippy lipo. I have no way of telling how many Amps I can go upto because my Turnigy wattmeter is only rated upto 130A. Maybe I'll purchase another one and hook them up in parallel.

Got the wings on and glued the fuselage halves together. She's finally starting to look like a plane rather than pieces of foam.

Now to work on the cockpit and gyros.
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Old Apr 26, 2010, 12:44 PM
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Munich
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Quote:
Originally Posted by Mtn_Commando View Post
This is great to know that she can take so much weight, thanks.
With the carbon fibre in the wings and good fans she flies well with that weight, but man, the approach velocity during landing is frightening ahem exciting :-)!

Cheers,
Henrik
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Old Apr 26, 2010, 12:47 PM
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Munich
Joined Dec 2008
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Does anyone get 2kgs AUW?

Hello,

just out of curiosity: Does anyone get an AUW of 2kgs as given e.g. on the Banana Hobby and ready2fly websites? I guess that is impossible, by a wide margin.

Cheers,
Henrik
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Old May 01, 2010, 07:38 PM
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Belgium
Joined Nov 2009
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Got to go flying tavarich


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Old May 02, 2010, 12:26 PM
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Munich
Joined Dec 2008
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Haha! Great pictures ! How did you treat the surface so that it became so shiny? And why did you not build the TV nozzles?

Cheers,
Henrik
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Old May 02, 2010, 10:00 PM
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good question. How ?
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Old May 03, 2010, 05:07 AM
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Belgium
Joined Nov 2009
42 Posts
For the shine, it s just some waterbase polyurethane floor lacquer that I got in my local surplus store. I t does not add soo much weight and it makes the surface more resistant to small dents and scratches.

I didnt wanted the TV cuz they looked soo flimzy and with a lot of play. also, I separated ailerons from the rest to get a more normal setup.

See ya all
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Old May 03, 2010, 05:32 AM
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Guys, for here in the US that would be Minwax Polycrylic. You can get it in a can or spray. Comes in Satin, semi gloss & glossy. If you want to stick with a flat finish then you can get Valspar Crystal Flat. It's a water based enamel. Comes only in a spray can & can be found at Michaels.
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Old May 03, 2010, 08:08 AM
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United States, CT, Danbury
Joined Jul 2008
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anyone had their maidens yet???
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Old May 06, 2010, 10:27 AM
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United States, CT, Danbury
Joined Jul 2008
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Ok, here goes., Another flight report.

After fixing all the crashes, the resaon was found out., The TV nozzles had so much play and moved in a weird spiral way at full throttle which caused the 2nd crash i did take them out after the crash.

Yesterday after reinforcing with CF and looking ugly from all the crashes, fixing it as far as possible, removing retracts, TV nozzles, chute, doors shut permanently and using metal gear servo's on the elevator. Hand launch is a breeze,. I am using a little lighter 3300mah lipo getting a decent 4 min flight. The intakes on the bottom of the plane are not at all needed, but is a good place to hand launch. It flops on landing like a trainer, good gliding abilities. i cut off the throttle around 100ft before the grass runway and landed right in front of me. High alpha is easy with the crazy canard-ali-elev mixing that i got from factory. I am going to get another su-47 later after this crash-test is done. However didnt plan to make it a crash-test dummy but ended up like that.

The elevator is quite sensitive on the plane, i took the linkage out and reinstalled it back in the 2nd hole from the bottom. The wings still flex like crazy, but i guess after all these crashes, this is how it's going to be.

Fair skies to all.
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