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Old Jan 16, 2012, 05:30 PM
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So we are adding more battery than needed to balance. Especially if Wars Rhino 4900mAh 6S is 730g pushed way back? War, what your battery weight?

This helps. The CG has a 10mm range and its near neutral. The further out, say forward 250mm forward in the battery tray, the more the weight has an effect to counter balance. Moving it 1/2" or 13mm could mean you could use lighter batteries or stay with these batteries and not worry about heavier motors; to some degree.


Quote:
Originally Posted by v8truckin
war

yes I hear a grind, but to me its sounds more as if its locking... Quick grind then click. Haven't heard that in any of the other freewings. I haven't any problems with it though. My Su doesn't balloon up like you say, could be our setups, but our cg is the same. Where in the tray is your battery? Mines about 1/2" from the front of the tray.
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Originally Posted by Wargassm View Post
this batt its all the way back.
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Old Jan 16, 2012, 05:43 PM
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Looks like the old FW bullet motors are lighter. So I should be ok with 4000 turnigys. Hope to start assembly by the end of week.
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Old Jan 16, 2012, 05:51 PM
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Originally Posted by Maxthrottle View Post
So we are adding more battery than needed to balance. Especially if Wars Rhino 4900mAh 6S is 730g pushed way back? War, what your battery weight?

This helps. The CG has a 10mm range and its near neutral. The further out, say forward 400mm forward in the battery tray, the more the weight has an effect to counter balance. Moving it 1/2" or 13mm could mean you could use lighter batteries or stay with these batteries and not worry about heavier motors; to some degree.
Thats why i was wondering where his battery placement was. Now just waiting on his battery weight. War says his is slightly nose heavy @ 150mm, but mine is also slightly nose heavy @ 150mm. So leaves me wondering...

War can you confirm that you have the 2300kv motors Max showed in this thread earlier, rather than the cone shaped? Wondering if our motors are different.

having trouble with vid quailty, Max. Vid looks good on phone 720p, but when I download it to PC & youtube look like 240p. Cant figure it out.
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Old Jan 16, 2012, 05:53 PM
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Originally Posted by v8truckin View Post
Thats why i was wondering where his battery placement was. Now just waiting on his battery weight. War says his is slightly nose heavy @ 150mm, but mine is also slightly nose heavy @ 150mm. So leaves me wondering...

War can you confirm that you have the 2300kv motors Max showed in this thread earlier, rather than the cone shaped? Wondering if our motors are different.
both are the same shape apparently, just one is a longer can; 39 to 49.
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Old Jan 16, 2012, 06:04 PM
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Originally Posted by SU-4ever View Post
Next time I'll be going RCCastle.

I feel really upset.
The very reason I decided to go R2F is, it actually comes from inside EU so there shouldn't be charges applied, nor delays due to customs.

But they're appearing to be inneffective. They where the first to announce aircraft and the last to get it.
That's not a good business!

R2F wrote she get the merchandise at the end of this month.
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Old Jan 16, 2012, 06:07 PM
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Originally Posted by v8truckin View Post
wargasmm, what is the weight of your 5300mah lipo. I balanced @ 150mm also but with a 5000mah 1/2-2/3" from front/nose of tray .
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Originally Posted by Wargassm View Post
752g.. its short and wide, 1inch back from the tray.
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Originally Posted by Wargassm View Post
last night i balanced it and its funny, my Genace 5300ma is 1mm wider than the battery tray. so i put it on its side and @ 1inch from the back it fits perfectly and balances @ 150mm ( weight 753g ). My rhino pack 6s 4900ma is 792gram but the pack itself is long, so it goes all the way back. But my thunderpwoers, not quite as long 50+grams lighter than rhino, all the way back and the plane is balanced @ 149mm.
Seems his Rhino 4900mah is longer than the 5000mah Flightmax im using
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Old Jan 16, 2012, 06:08 PM
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Originally Posted by Maxthrottle View Post
both are the same shape apparently, just one is a longer can; 39 to 49.
you refering to the 2 motors, the one you posted & the coned can are both 2300kv.
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Old Jan 16, 2012, 06:19 PM
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it looks like this only all black says 2200KV on box http://www.ebay.com/itm/70MM-EDF-280...=item27b53ddc5
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Old Jan 16, 2012, 06:26 PM
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Originally Posted by Maxthrottle View Post
Possible cause for your ballooning;
Think of your little balsa glider kits for ages 6 and up...
Metal weight in the nose, and a stab in the tail at 15* or so. You toss it with all your might and it does this big circle over head and comes back and almost takes your eye out; big fun. Then as it bleeds off its speed, the stab pitches it up till it loses speed, the metal weight takes over, it stalls, starts to pick up speed again making the stab effective again and keeps doing this till it reaches the ground.
If you were a little inventor and tried adding a rocket motor on it, you would need the motor to pitch the nose down some or it will just do the big circles till it runs out of steam. So to counter the stab, the thrust angle is snow plowing against it to keep a straight line. So it rockets along till the motor cuts out removing the pitch down force and what happens... the stab sends it skyward.
This is the SU-34 thread all over again and I dropped out of explaining this because many focused on the cheat hole others decreased the pitch thrust line and added more down pitch in the elevator or added down input in the canard. What is a waist is having the surfaces plowing against each other.

I confirmed this and can now share how. My brother used to work as a sensor tech at a wind tunnel and while visiting him to do a tour, having discussed my new model, he asked me to bring it for them to put it on the stand. They were setting up and array so they had to do a run up anyways but they asked that I don't mention the company. As soon as the staff look at the 34 they immediately said the stab is set for an aggressive glide slop and asked if it falls flat to the ground. I also asked about the effect of cheats. They confirmed they do have this effect but it is so minor that it is easily blanked by pitch input. They added if flight dynamics worked like that you'd see intakes on the tops of everything but there isn't because the moment any pitch up is added the air fowls and chokes any intake because of the changed direction and pressure changes adding that its well documented with aircraft that have tail mounted engines on nacelles. The wing at certain AoA fowl the intake. Anyways....We set it up and it was all exciting confirming what I described above right up until it slipped off the stands and got damaged bouncing on the ground till it reached the pick up mesh. I fixed it and added full flying stabs and it flew great till I damaged it again at which time the F-35 and Euro came out so it got shelved.

They showed me a lot about flight dynamics etc which is one reason why I guess I try to relate solutions in a similar manor.
hobby models are for the masses. Anyone can get one so they are set up to go into this basic stable glide. But its not optimal to other things that it is capable of doing. So for ballooning you may just need to take a little pitch out of the stab. You do this already as you set up to land because to come down out of your glide you pitch down.

The Canard deal was discussed then too and the odd thing is the SU35 and 34 have the same characteristics but only one has a canard. So then process of elimination, would it be the canards? Just like the little glider with a fixed stab the stabilator on these are setting your wings AoA and the thrust line is set to counter increasing lift developed by your wing because that's what down thrust is for, more thrust, more speed, more speed, the greater the lift generated at the wing. But with aggressive stab settings you have an increased lift effect and thus the thrust angle is countering both the wing lift as thrust increased and the stabs pitch up effect.

Try it or do the research but just to give everyone an alternate perspective.
Nicely explained, I fully agree.

I'd pay to see my model airplanes in wind tunnels!

That had to be a unique experience.

As for the ballooning effect, there's still one more thing to add to the equation. Sukhoi has very well designed LERX. They don't contribute much at level flight with some speed but when slowing down and increasing AoA, they generate low-pressure vortices over the wings thus creating serious amount of lift. Unlike other jets without LERX, this will cause the plane to "Balloon" if pulling up without making a clever and smooth use of pitch control. At speed, very little AoA change will create big difference in lift. This airplane is designed that way.

Having this in mind and not pitching up suddenly on approach, you can use those lift vortexs to your advantage, rather than letting the plane jump up when you intend to slow it down.
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Old Jan 16, 2012, 06:28 PM
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Originally Posted by v8truckin View Post
you refering to the 2 motors, the one you posted & the coned can are both 2300kv.
They look the same. The only difference is one is longer. Not sure where the cone is coming in. One is a 2200kv 39mm long the other newer a 2300kv 49mm long. Same ends more coil and magnets added.

I'm actually wondering if this may be the cause of the delay with R2F since they tend to seek improvements. If they are unhappy with the lower thrust the initial batch is showing they may have waited for the newer motor. Who knows but it would be nice for those who get the improvement.
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Old Jan 16, 2012, 06:30 PM
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Originally Posted by SU-4ever View Post
Nicely explained, I fully agree.

I'd pay to see my model airplanes in wind tunnels!

That had to be a unique experience.
All geeks and nerds but it was a hell of fun day even though it crashed my model in the process.
Technically they are not LERXs because they are not attached to the fuse so they are still refered to as canards but yes their purpose is as you describe. However, the 35 doesn't have them as the 27 and others in the same class and the issue wasn't ballooning it was buffeting and less of a turn radius. The Canards help to clean the air flow but was heavy.
With the S and BM using lighter materials and the rudders assisting the turn improved and the slightly changed strake reduce the buffeting resulting is better performance bbecause they were swing less weight around with better control without adding more surface area and thus drag.
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Old Jan 16, 2012, 06:35 PM
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Originally Posted by Maxthrottle View Post
All geeks and nerds but it was a hell of fun day even though it crashed my model in the process.
Hey, where would we be without geeks & nerds! lol!
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Old Jan 16, 2012, 06:40 PM
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All geeks and nerds but it was a hell of fun day even though it crashed my model in the process.
Sorry for your model... what happened? did they try push past the sound barrier? Would love a video of that xDDD

Geeks rule, normality is overstated.

Ya know, I study Aeronautical Engineering and we're pretty much geek, one way or another. Its half of its charm / fun.
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Old Jan 16, 2012, 06:45 PM
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In fact, I'm seriously considering to do a stall-essay ont the eurofighter wings, sticking white threads all over its surface and filming with a little HD camera on-board. It'd be nice to know at which AoA the boundary layer detaches in our models. It'd help better understanding the flight capabilities of these aircraft.
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Old Jan 16, 2012, 07:00 PM
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Originally Posted by v8truckin View Post
Seems his Rhino 4900mah is longer than the 5000mah Flightmax im using
the 4900 is 173mm but flight max at 842g that's a 5000 40C 153mm. I thought you were flying a Nano.

The length works the opposite. Half his 173mm batt is 86.5mm which is where the battery weight is excerting force if it were at the bulk head.
Half of yours if its 153mm is 76.5mm and if you are 13mm back from the bulk head that puts you with a heavier battery 89.5mm back off the forward bulk head which is 3mm difference. But he said way back so he's also likely even further back off the bulk head with a lighter battery and CGing at 150mm.
So someone is either at the wrong CG, has different motors or something.
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