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-   -   Model setup (https://www.rcuniverse.com/forum/3d-flying-82/11669694-model-setup.html)

MHFlyer 09-16-2019 11:06 PM

Model setup
 
Hi all,

I'm new to the forum so any help would be much appreciated.

My question is how do I best set up my model for 3d? I've done lots of f3a flying over the years but no 3d.

So if I want to perform a hover and harrier for example what do I need to do with setup

The models I'm using are a T Storm 89"Slick/GP76/Falcon24x9 and an AJ Laser 73"/DLE 35/Falcon 19x8

I've seen the models hover great on YouTube just don't know how.

Many thanks

Steve

BarracudaHockey 09-17-2019 04:43 AM

Neutral CG

Lots of throw and a decent amount of expo helps. If you fly F3A you're probably used to a lot less throw and less expo for more precise control. High rates on my 3D birds are bevel to bevel with long servo arms and 40 or 45% expo.

And practice, lots and lots of practice.

Hovering and high alpha post stall flying is all about using the engine to blow air over the control surfaces versus using the airspeed of the model to create control authority.

And welcome to the forums!

speedracerntrixie 09-17-2019 06:25 AM

I would like to add that you are usually running at least a 1:1 ratio with your servo arm/control horn so select servos accordingly. For F3A we are usually a bit light on our servos because we run servo arm that give us good mechanical advantage. Not so much with 3D, I have seen many pictures of guys with a 6" double servo arm on their rudder.

MHFlyer 09-17-2019 09:14 PM

Hi guys

Thanks both for getting back to me gives me a good starting point,

Any thoughts on props? Bigger prop with less pitch?

Joseph Frost 09-17-2019 10:24 PM

https://cimg9.ibsrv.net/gimg/www.rcu...47958efa45.jpg

I love daily prax in my backyard with variety of foamies.
https://cimg8.ibsrv.net/gimg/www.rcu...51baae92aa.jpg

Playing in the breeze with light w/loader.
https://cimg2.ibsrv.net/gimg/www.rcu...892a38ff24.jpg

Prax with foamies makes it perfect for more serious ones.
At least 1.5 to 1 power to weight, lot of travel and definitely no +expo for 3/D, with expo you are defeating the purpose! You need instant correction response for all controls, not mushiness. For 3/D performance I personally prefer larger Dia. with lesser pitch props.
Naturally, lot of prax, ideal to have few smaller foamies to keep it up.

ahicks 09-18-2019 04:38 AM

Yes, prop diameter is your friend in 3D. A lot of pitch isn't necessary either. A flatter prop helps control your speed on down lines, increases vertical performance, and acts as an air brake when you need one.

I second the neutral CG, which may be quite away back from what many are used to. This is useful in a couple of scenarios, the first being for play in post stall air speeds. Snap happy planes are no fun here. You want a plane that can slow WAY down. A plane wagging it's wings from side to side is trying to tell you it's getting ready to stall. Not good! A plane the requires excessive up elevator to hold the too heavy nose up no fun either. If you get air flow separation over the elevator, because of that excessive angle it has to run at when slowed, that plane is going to be headed straight down in very short order with very little warning. The plane's tail should drop noticeably as it slows, to something like a 3 point landing attitude.

A tip for flying at these speeds. The ailerons are not very effective at all when you slow down like this. It's important to get used to picking up that low wing with the rudder, not just the ailerons.

The other thing the neutral CG gives you is a flat elevator. If you have up or down trim here, and you roll the plane over on it's side, there's little chance of it tracking straight on KE. It's going to go towards the gear if tail heavy, and towards the canopy if nose heavy. Flat elevator for starters, but you may have to add some mixing if that doesn't leave you close enough.

Oh, and last, foamies are cheap to buy and crash when flown low and slow and very close in. Many will learn their basic 3d setups and get their flying/muscle memory basics started with one of these. Some of them are excellent fliers! I can almost guarantee they can save you some really expensive mistakes when learning this stuff with a gasser.

Welcome to 3D. Best of luck!

MHFlyer 09-18-2019 09:22 PM

Joseph, ahicks

Thanks for posting, all useful stuff, I'll buy a couple a foamiesto get me going 👍🙂

Joseph Frost 09-19-2019 12:40 AM

https://cimg9.ibsrv.net/gimg/www.rcu...d641d8b680.jpg
https://cimg0.ibsrv.net/gimg/www.rcu...e5c619f638.jpg
Hi Ahick, enjoyed your read, { Quote-I second the neutral CG, which may be quite away back from what many are used to.} assuming you meant that lot of fliers fly nose heavy?
Actually I don't mind setting my 3/D models on tail heavy side as I do lot of hovering manuvers and with plenty of power I can get out quickly out of any trouble, if in need,
Interesting when you mentioned 'wing rocking side to side', last few days I have re-designed this tiny, very light "Hummer" model {550g} by enlarging the wing area to slow it down for more "slow&low" fun, but while flying it this morn in dead calm the thing was rocking the wing a lot, wanting to stall most of the time as I was trying to minimize its speed.

Joseph Frost 09-25-2019 01:23 AM

https://cimg0.ibsrv.net/gimg/www.rcu...669f79ceca.jpg

New 12x4.7 prop for "Humber" toy.
https://cimg2.ibsrv.net/gimg/www.rcu...38a64fc043.jpg

More stable with the larger prop.
https://cimg3.ibsrv.net/gimg/www.rcu...4094b44852.jpg

Slow, light wing loader.
https://cimg5.ibsrv.net/gimg/www.rcu...fee784777e.jpg

Close up fun.
Test flying it this morn with larger E-prop, (12x4.7) still nice and slow but prop wash spread over the wider control surface. Lot more fun with my own design, "JF Design" one, I have built years ago for slow flight in dead calm or indoor fun. This one spins 13x4.7 on 3S, I just love flying i, it's so graciously slow.

Uranusman 04-21-2020 04:10 AM

I want to know the same thing, I'm about to start doing it.

ahicks 04-22-2020 04:16 AM

Just starting, I would set the plane up as a good sport flyer on low rates, then start increasing the throws and expo on high rate. Take your time and get to know the plane. When right (45 degree throws either side of center with sufficient expo to handle that) you may start to forget to come down on to low rates.

CG is critical. Level flight with a flat elevator is a good start. If there's up elevator trim, you're too nose heavy. Tail should settle a little as the plane slows. You'll have to add a little power to maintain that attitude while not loosing altitude.

Last, don't believe even for a second a plane set up like this is going to 3D right off the bat. 3D is not just about plane setup, it's about a degree of control that many never achieve. That's going to require stick time. A LOT of stick time! The more you fly the better you get. It's that simple.


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