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Old Oct 20, 2012, 11:40 PM
CarreraGTSCS is offline
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Lori, hey, you're home early
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Originally Posted by v8truckin View Post
I would but I don't have the stock mains any longer, im using the euro struts.

Dro5,

Congrats!
Thanks. Maybe someone else can chime in.

Mike
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Old Oct 21, 2012, 03:37 AM
Odysis is offline
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Life begins at transition
Another one gets it's wings!

Managed to get up for a few laps in fairly blustery conditions today. All up, I think this jet's a winner

Did the usual 'landing gear too far aft' pop off the runway. I lined up with 250' of runway (tarmac), held about 1/2 backstick and opened the taps. With 50' to run, and no nose wheel liftoff, I pulled more, and immediately got to 45 nose up!

Good point: Heaps of power to maintain 45 nose up

I used the Su34 as a warm up, and there are some similarities in handling qualities, but the 35 certainly feels more grown up (bigger, heavier, more predictable)

Landing was a doddle, and roll out was only around 200'.

Me likey
Old Oct 21, 2012, 04:36 AM
dro56595@bigpo is offline
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Originally Posted by Odysis View Post
Another one gets it's wings!

Managed to get up for a few laps in fairly blustery conditions today. All up, I think this jet's a winner

Did the usual 'landing gear too far aft' pop off the runway. I lined up with 250' of runway (tarmac), held about 1/2 backstick and opened the taps. With 50' to run, and no nose wheel liftoff, I pulled more, and immediately got to 45 nose up!

Good point: Heaps of power to maintain 45 nose up

I used the Su34 as a warm up, and there are some similarities in handling qualities, but the 35 certainly feels more grown up (bigger, heavier, more predictable)

Landing was a doddle, and roll out was only around 200'.

Me likey
Great stuff.

Wow, that's a lot of run. TV came in handy, eh?
Old Oct 21, 2012, 04:48 AM
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Life begins at transition
Nope, TV off for the maiden.

I knew it'd probably stick to the runway, but was hoping for the best.

I'd love to move the mains forward a bit, but that defeats the purpose of "just fly it"!
Old Oct 21, 2012, 04:54 AM
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Originally Posted by Odysis View Post
Nope, TV off for the maiden.

I knew it'd probably stick to the runway, but was hoping for the best.

I'd love to move the mains forward a bit, but that defeats the purpose of "just fly it"!
Roger. I had mine on. Even though it's a beautiful grass strip, it's still hard on the nose gear and I wanted the weight off ASAP. I was a little worried that the TV would be too effective and I'd over control close to the ground, but it was sweet.
Old Oct 21, 2012, 05:17 AM
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Life begins at transition
Cool - that's what I was worried about, but having a 500' tarmac strip, I thought I'd be fine.

Of course, I decided to start the takeoff roll in front of the pilot box. That extra distance could have made things go just a little sweeter!

Now I know what 'flying speed' looks like, I'm sure I can get it up a bit smoother.
Last edited by Odysis; Oct 21, 2012 at 06:37 AM. Reason: Add glory shot!
Old Oct 21, 2012, 05:20 PM
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You are a "go" for reentry
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Odysis; you mention wanting to move the mains forward. This was posted early.


They are fairly close to scale and CG so unless you have yours nose heavy, you risk getting it too close it falling back on its tail with a little bouce.

Convention has the mains 10-15* aft of CG.
Old Oct 21, 2012, 06:59 PM
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Life begins at transition
Good point re scale, but we also have our CoG's further forward than the real one.

I will try moving it around, moving the mains is too hard! Makes takeoff nicer, but landing tougher. Everything's a trade-off...
Old Oct 21, 2012, 10:01 PM
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You are a "go" for reentry
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Odysis, not that I'm arguing but what would change the CG for the model from scale? The provided symmetrical foil still maxes around 35% to the full scales 40% and the wing area and sweep are the same. So little change to reposition MAC or CG. The CG doesn't really reach neutral unstable till you pass 165mm-167mm.

Not sure if it being a fighter changes minds that fighters are only tail heavy. Fighters go tail heavy by a load shift after takeoff during engagement. If they were tail heavy static they would flop back on their tails! Even while being loaded with ordnance, they don't fall back on the tail.

The flip side is its important not to make it too nose heavy to exacerbate the problem.
Old Oct 22, 2012, 12:06 AM
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Maybe try adjusting the gear (raising the nose, lowering the mains) to add some positive alpha on the ground.
Old Oct 22, 2012, 06:29 AM
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After my first two flights yesterday, I put her on the bench to have a better look at the ESC cooling setup.

What initially looks like a fancy grilled scoop to direct air over the stock ESCs with their cooling fins, I noticed that there was nowhere for that scooped air to flow to (except a couple of small slots where some servo leads come down into the cable run).

That scooped air would pretty much stagnate and provide very little cooling mass flow.

An easy fix would be to remove the rear portion of the cable run cover to provide some flow through, but that will only work when there's forward airspeed. The fancy TV moves are usually high power but low forward speed.

I thought about relocating the ESCs into the intake ducts, but that would have required major surgery and I'm a lazy modeller. So I drilled some new ducts from the main exhaust ducts back into the cable run cavity - the theory being that the efflux will create a venturi effect that will suck air through the cable run and past the ESCs, especially during high power phases.

Might be a waste of time. Will report if it makes any difference when I fly next.

Cheers,

Dan.
Old Oct 22, 2012, 06:56 AM
Odysis is offline
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Life begins at transition
The Su35 is fly by wire, therefore I assume statically unstable.

So I'd like to move the mains back a bit, the nose back a fair bit. Keep the 15deg CoG-main wheel contact point relationship, and 10:1 main:nose wheel weight.

As for jets re-arranging their CoG inflight - not any I've seen! I know a 747 can do it, but an F111 was the only jet I'm familiar with that had anything even remotely like trim tanks. A hornet for example, the fin tanks are mostly as vents...

either way - I'm sure once I figure out my personal CoG preference, and what a decent amount of elevator is, I'll be able to get a much nicer takeoff.
Old Oct 22, 2012, 08:03 AM
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What's true for the real plane does not necessarily hold for the RC version. Design compromises are made for materials (foam vs metal) and stability.

Shifts in real plane CG usually happen because of fuel consumption. One solution has been to sip fuel from different tanks over time.
Old Oct 22, 2012, 09:07 AM
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Should've, Would've, Could've
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Dro5,

You should look into Max's mod for air movement through the esc vent and channel via the fans drawing air through holes cut into the side wall of the intake walls. Its a great lil mod that utilizes the fans draw to create flow and movement over the escs and exit.
Old Oct 22, 2012, 09:57 AM
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I agree with V8. Max's mod is by far the best method with the least butchering. I fly at high altitude and heat in the high desert and have not had any overheating problems at all. Regards CG... I started with mine set in the middle of factory suggestion. I have moved my 5000 battery pack further back in increments of 1/4" until I'm now about 1 1/12" to the rear and the aircraft flies perfect for the entire flight envelope.


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