SmartDart xs-f

[Grasshopper]

Anyone built and successfully flown a SmartDart xs-f ?

 

 

Here is my one.

 

This is a Flight Line Plans design in Depron and the plan is available from Micron. I faithfully followed the plan using all the correct materials but the resulting 'plane is a complete nightmare. With some effort it is possible to carry out (indoor) circuits but any change in the controls results in heart stopping dives, stalls, prop hangs etc. I have turned down the rates and piled on the expo but to no avail.

 

After 2 testing sessions at the Club hall I have now virtually given up on the thing and removed the receiver,servos etc. for use in another 'plane.

 

Anyone else got any experience - good or bad to pass on ?

Edited By Grasshopper on 08/01/2010 16:18:58

[birdy]

Is the CoG in the right place?

[Grasshopper]

Hi Birdy,

 

yes this was my (and 10 other folks!) first thought. Initially is was spot on according to the plan but after a couple of bad flights I moved the LiPO back 1 cm and then forward gradually until it was 1 cm in front of the original position. This was moving the CofG lots and although it changed the flight characteristics it did not make it in any way stable.

 

In fact with the CofG forward of the indicated position the thing did little but prop hang which seems odd. Normally forward CofG gives unwanted stability - but not on this one.

[Mark Millward]

I have built a few versions of this and all need a good bit of dihedral

[Grasshopper]

Cheers Mark - assume if you built more than one that you have had no handling problems?

 

Mine has what I believe to be the correct dihedral - wing tip to wing tip is 54.1 cm. Any chance you could do a quick measure on one of yours?

[Myron Beaumont]

You know what "they" say ? If it looks right it is & if it doesn't ----

[Dave Bran]

The ex-AMA now RC Dart family is one of the CLASSIC Indoor designs, dating from Free Flight days, with a massive following, so the overall plane design has proven itself hundreds of thousands of times over. Myron, you could not be more wrong re: looks and action in this case!!!

 

The Flight Lines Plan is a minor adaption of a massive worldwide phenomenon.

 

I have entered international postal competitions with my Darts! (Which included against the clock loops, bunts, inverted flight, limbos, prop-hang and rolls!!)

 

As to yours, you do not say enough, nor are the pictures good enough to tell exactly, but:-

 

1. It's NOT Dihedral. I have had them with much more and less than yours, to little major effect

 

2. I could and did many times in demo trim mine "off", put the Tx on the ground and let it fly itself in big circles (indoors and out!!), Stability is NOT an issue normally. Despite this it'll roll tightly, fly inverted, do bunts, I can even prop hang mine slightly inverted!!!

 

Two examples..................

 

http://www.atomic-album.com/showPic.php/22727/Two_Darts_Front_Web.jpg

 

http://www.atomic-album.com/showPic.php/22727/Two_Darts_Rear_Web.jpg

I have seen the FL Plan and I know it flies well, even built fairly poorly. Have flown three built by others, they all worked very well.

 

You therefore have something very wrong.  (And I DO mean drastically wrong!!)

 

Please provide all up weight, and pics/dimensions showing motor alignment, tailplane incidence (important), and we might be able to help.........................

[Dave Bran]

Have just blown your pic up as much as possible, and while difficult to tell, the motor down thrust does not look right.

 

And please tell me the lines across the wing are not Aileron hinges, this is a T/R/E plane.

[Grasshopper]

Hi Dave,

 

OK, you can stop the head banging on the desk, I know from experience it doesn't help!

 

And yes there is something drastically wrong here but my experience of 20 years or so has not shown me what. I currently fly Easy Glider, Easy Star on motor and slope, a 2.5 metre balsa R/E sloper,  and several others like Foamie Dave's EPP Moth but this one, well wow, got me beaten.

 

Not able to supply a pic. just now -  but have some answers for you.

 

All up weight - 131 g.

 

No, not ailerons, after first flights I cross braced the wing/dihedral and also the wing to 'body' with carbon as I thought that when turning off the straight and narrow, the wings were flexing relative to the tail feathers.

 

Motor mount, well on the last flight the motor was snapped off the mount so we cannot tell now. I did however follow the plan extremely carefully so I can only assume that it was correct.

 

CofG was altered by 1 cm either side of the given position and while this greatly changed the handling it did not make it truly stable. It would fly in a nice oval round the hall and seem to be OK but then when you tried to do a slow 360 it would prop hang or dive into the parquet.

 

I will try to take some pics. tomorrow to show the tail incidence.

 

 

 

 

 

 

 

 

[Grasshopper]

Dave,

 

couple of pictures of the tail of my SmartDart if you want to try and work out the tailplane incidence.

 

 

 

What do you think? Any answers here?

 

Edited By Grasshopper on 18/01/2010 13:06:19