RC Slope Soaring in Hong Kong

Dear All,

I got a plane named AKRO STAR. With study building instructions and finding the plane features a free-floating spar joiner system. I cannot catch its meaming , any one has any idea

Many Thanks
Kailas[/list]

Hi Kailas,

I have an AkroStar.

Conventional spar system has the spar tightly fit in the fuselage as well as the wings. The floating spar simply means the spar does not touch the fuse. In theory the spar carries the load and the fuse has nothing to do with it. So with the alignment pins to fix the wings it is in fact a redundance for the spar to fix on the fuse.

Another famous model that uses the floating spar is the Elitar.


May I ask where did you buy the Akrostar? My friend in Taiwan want to buy one but this model is out of the market for very long time.

Hi Kailas,

From my understanding (Multiplex AKRO STAR)

- The wing is mount to body mainly by the front/rear pin (not by the wing join)
- The wing join do not attached to body directly but join the two wing segment together during air born

Below please find some reference pictures:




Cheers,

(景)

Dear All

King , much thank your photo, it is great!

CM , yes, the plane is out of market. I got it from second hand market and it is not assembly at all

The system is beyond my knowledge. Would you mind to tell me more about this system . What is its advantage.

Kailas

Hi Kailas,

It is a nice plane. You are so lucky to find an unbuilt one

As I know full scale sailplanes use floating system, but most of the models are still using the old spar system. I think the floating system may have its merit, but not so significant to make all the others change to it.

I think the advantage of the floating system are

1, The wings and the spar carry the load. The force acting on the fuselage by the wing is actually not as large as one might think. The fixing pins are enough to hold the wings on the fuselage. There is no need to fix the spar on the fuselage.

2, Fixing the spar makes alignment job difficult because we must make sure all the 3 parts (front and rear pins, and the spar) are well aligned.

3, Save the work in fitting the spar on the fuselage.

Anyone can suggest other advantage ?


In theory it makes sense to use the floating spar system: The pins set the wing incidence and the spar carry the load. It is easy to set up (for full size) and there is no redundance in functions. But I think these are not so important in our toy aeroplanes than in the full size. On the other hand, a fixed spar on the fuselage can also secure the wings by friction, while floating spar need something extra to lock the wings. In King's photos, the little device in front of the spar is the wing lock. (Your kit does not have this wing lock. It is not a standard item in Akrostar)

This wing lock is factory design made by Multiplex as same as my Euromaster, it will be fit tight between the wing & the fuselage, even you don't put the tape on for fly. I think you can find it at Tak Cheong.