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Old Feb 04, 2013, 08:13 AM
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What would you like to see in a Twin Star III ?

The Twin Star II is one hell of a great airframe but it was designed for an era where brushless power systems and lithium batteries were presumed to be out of reach by the typical foamy RC plane buyer. Because of this, we have a plane with a very thick airfoil and a lot of wing area and not much accommodation for high speed handling (since Speed 400s just won't get you there). It's hilarious to think that the same power system was supposed to propell a sleek jet shape like the Sonic Liner when it's just adequate for a plane like the Twin Star II. Ah, the early 2000s... We have come a LONG way, foks!!

I have built two of them now, my current one has ~1000W on 4s and flies like a dream but WOT results in flutter, despite extensive carbon reinforcement...and it wastes an alarming number of Watts. It could lose 1/3 of the wing and still be a floater! Still, I enjoy flying on 3s and just floating around with it but it feels like a much more entertaining plane is lurking behind the inherent weakness of the old design.

What do you think a TS3 should be like? What do you want to see?

My thoughts:
-The basic shape and look (with "passenger plane" aesthetics) should be kept but some modernizing would be great.
-strong carbon (or fiberglass) wing reinforcements that extend farther into the wing
-slightly thinner airfoil
-a thinner, more stylish horizontal stab
-a less "Nerf inspired" nose with better aerodynamnics
-mid wing configuration would alleviate the odd nose-down aoa issue when flying a TS2 at high speeds
-more universal motor mounts
-accommodations for landing gear
-accommodations for wing-mounted ESCs (since BL planes need two)
-denser more modern Elapor

Thoughts?
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Old Feb 04, 2013, 08:33 AM
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I just built my first Twin Star.

Accommodations for brushless motors would be a good upgrade to make to the kit.
Maybe a balsa insert into the nacelles that in include a firewall for mounting the motor and holding the ESC's underneath.

I used HobbyZone Super Cub landing gear on mine and think a similar system would be great to have. The gear simply clips in if you want them or are easily in clipped out if you don't.


Here's mine:
http://www.rcgroups.com/forums/showthread.php?t=1824172
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Old Feb 04, 2013, 09:05 AM
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TSlll, hmmm.... Interesting idea. However, I like my current ESll and it's scale-like flying so much, that I wouldn't like to see the concept transformed into a high speed projectile

Sorry, but I actually like it to fly slow, and I like the payload capability of it. And when flying it, I don't sense any 3D-pylon-racer-monster-twin lurking anywhere
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Old Feb 04, 2013, 10:01 AM
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TSlll, hmmm.... Interesting idea. However, I like my current ESll and it's scale-like flying so much, that I wouldn't like to see the concept transformed into a high speed projectile

Sorry, but I actually like it to fly slow, and I like the payload capability of it. And when flying it, I don't sense any 3D-pylon-racer-monster-twin lurking anywhere
I mostly agree here....There is definitely a place for slow flyers and I certainly don't think a hypothetical TSIII should be transformed into a "Twin Star Ultra" where the general handling is compromised...but the TSII has so much extra wing that it wastes precious amp hours, even when flying in the intermediate speeds for which it's designed.

With ~120W and heavy nickel batteries, the TSII was a good compromise and needed every mm of that airfoil...I don't think that's necessary anymore.

My hunch is that slightly a more sporty profile could greatly broadened the performance envelope and keep the plane from growing tiresome so quickly.

Not every plane needs to fly like a trainer.
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Old Feb 04, 2013, 10:05 AM
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Landing gear and just a simple ply plate in the nacelle for "X" mount motor attachment. Then a nice cowl and cockpit too.

That will do.
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Old Feb 04, 2013, 01:17 PM
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Originally Posted by MRGTX View Post
...
My hunch is that slightly a more sporty profile could greatly broadened the performance envelope and keep the plane from growing tiresome so quickly.

Not every plane needs to fly like a trainer.
The Twin Star II really hasn't got a thick wing section. The width at the wing root is 225mm and the max thinkness is approx. 28mm, giving it a thickness ratio of approx. 12.5%, which is perfectly normal for an electric powered motor model.

In order to significantly reduce the drag, you would need to change the aspect ratio of the wing (to reduce induced drag), reduce the cross section of the (fat) fuselage, smoothen the rough surface and making the trailing edges thinner. But then, it would not be the docile trainer anymore it was designed for.

Not every plane needs to fly a trainer. True, but a trainer should fly like a trainer.

Jürgen
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Old Feb 04, 2013, 02:10 PM
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Originally Posted by Jurgen Heilig View Post
The Twin Star II really hasn't got a thick wing section. The width at the wing root is 225mm and the max thinkness is approx. 28mm, giving it a thickness ratio of approx. 12.5%, which is perfectly normal for an electric powered motor model.

In order to significantly reduce the drag, you would need to change the aspect ratio of the wing (to reduce induced drag), reduce the cross section of the (fat) fuselage, smoothen the rough surface and making the trailing edges thinner. But then, it would not be the docile trainer anymore it was designed for.

Not every plane needs to fly a trainer. True, but a trainer should fly like a trainer.

Jürgen
I agree about the aspect ratio...I'll take your word for it on the "normality" of the airfoil...I never measured it. The point is, the plane is unnecessarily draggy. It has lift to spare.

What I will disagree with you with your implication that the Twinstar II a trainer. At least here in the US, it's sold as a model for intermediate pilots...it's not marketed to beginners.

Let me just remind anyone who cares to participate- this is a discussion about what YOU WANT IN A TWINSTAR 3... not a debate on what it should be based on what it has been in the past.

Jurgen, please don't troll this thread.
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Old Feb 04, 2013, 07:11 PM
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I would like to see it as a seaplane .
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Old Feb 04, 2013, 07:58 PM
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They make a add on for that. Not multiplex but someone else.
Has a belly piece that kinda gives it a wider bow and then wing pontoons.
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Old Feb 04, 2013, 08:29 PM
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They make a add on for that. Not multiplex but someone else.
Has a belly piece that kinda gives it a wider bow and then wing pontoons.
Keith at Parkflyer Plastics has the kit. There is a thread here too.

Mike
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Old Feb 04, 2013, 09:24 PM
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MRGTX,
Twinstars sold in Oz (so I assume elsewhere) come with a brushless kit system. I've actually been flying mine with brushless motors for a couple of years and these from HobbyCity were matched up to Castle Creations 25amp ESCs and 8 X 4 clockwise and counter clockwise Zinger props.

The undercarriage system was self designed but the nosewheel leg adapted from a HobbyCity sprung loaded unit.

Even prior to my use of brushless I always used 3S Lipos on the 400s. These were run in underwater and then used 7 X 4 props. On two Twinstars these gave over 100 flights without problem.

Incidentally the brushless units I fitted use the standard brushed mounts with minimal alteration. In both forms however all of my Twinstars have been capable of full aeros or at least all the ones I can do!!!
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Old Feb 05, 2013, 01:24 AM
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Originally Posted by MRGTX View Post
I agree about the aspect ratio...I'll take your word for it on the "normality" of the airfoil...I never measured it. The point is, the plane is unnecessarily draggy. It has lift to spare.

What I will disagree with you with your implication that the Twinstar II a trainer. At least here in the US, it's sold as a model for intermediate pilots...it's not marketed to beginners.

Let me just remind anyone who cares to participate- this is a discussion about what YOU WANT IN A TWINSTAR 3... not a debate on what it should be based on what it has been in the past.

Jurgen, please don't troll this thread.
I am merely correcting some of your statements. The Twin-Star II has not got a thick profile. It has a big fuselage (= draggy), which is integral part of the character and appearance of the model.

I never wrote, that the Twin Star II is a beginners model (like the EasyStar for example). It makes a great ailerons trainer however.

You obviously don't seem to want a TwinStar III, but a completely different type of model.

Jürgen
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Old Feb 05, 2013, 07:33 AM
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Originally Posted by David Hipperson View Post
Twinstars sold in Oz (so I assume elsewhere) come with a brushless kit system.
I ordered mine (Kit form) from Germany, and it came with the Speed 400 motors and props.

BTW: Great picture of a nice TS!

EDIT: Looking at David's nice TS, I could perhaps wish for a 160cm, semi-retract wheels, DC-3 tail-dragger like model with a lot of that nice TS DNA in it. Now that power has become so cheap and available, larger models are easier to power
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Old Feb 05, 2013, 09:42 AM
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Originally Posted by Jurgen Heilig View Post
I am merely correcting some of your statements. The Twin-Star II has not got a thick profile. It has a big fuselage (= draggy), which is integral part of the character and appearance of the model.

I never wrote, that the Twin Star II is a beginners model (like the EasyStar for example). It makes a great ailerons trainer however.

You obviously don't seem to want a TwinStar III, but a completely different type of model.

Jürgen
I'm not going to argue with you again.

If you'd like to share your wishes for a hypothetical TSIII, please do so. Otherwise, please make a graceful exit.
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Old Feb 05, 2013, 09:45 AM
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Originally Posted by David Hipperson View Post
MRGTX,
Twinstars sold in Oz (so I assume elsewhere) come with a brushless kit system. I've actually been flying mine with brushless motors for a couple of years and these from HobbyCity were matched up to Castle Creations 25amp ESCs and 8 X 4 clockwise and counter clockwise Zinger props.

The undercarriage system was self designed but the nosewheel leg adapted from a HobbyCity sprung loaded unit.

Even prior to my use of brushless I always used 3S Lipos on the 400s. These were run in underwater and then used 7 X 4 props. On two Twinstars these gave over 100 flights without problem.

Incidentally the brushless units I fitted use the standard brushed mounts with minimal alteration. In both forms however all of my Twinstars have been capable of full aeros or at least all the ones I can do!!!
David- nice picture!!
Your plane sounds great...

What are the specs on the BL motors? Are they 28mm inrunners? That was the easiest swap that I could find to the stock mounts. Unfortunately, inrunners are less popular these days and they tend to be spendy because of that fact.

Many folks have done landing gear installations (yours looks to be well done)...but some factory plates allowing for easy installation/removal would be a nice change.

What else would you like to have changed/updated?
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