Aerodynamic balance on Rudder for Skyranger Microlight

[kuldeepchana]

Hello to everyone,

I need some help...I am currently studying my final year at university and the dissertation project that I have chosen is 'The optimisation of cockpit controls and control surfaces of the Skyranger Microlight'.

I have been looking into optimisaing/altering the rudder which is used on the skyranger.
I was thinking of optimising the rudder by using a aerodynamic balance tab.
I have done some research and have an understanding that aerodynamic balances tabs (horns) are used to reduce the stick forces required by making the size of the hinge moment smaller.
Recently I have found this NACA paper which states that angles of yaw upto 20 (degrees) had no appreciable effect on the reduction of hinge moments due to tabs.
(http://aerade.cranfield.ac.uk/ara/1936/naca-report-528.pdf)

If you look at similar aircraft such as the C152 and the PA28, they use Aerodynamic balance tabs.
But if the case from the NACA paper is true then why bother using the tabs?
Before I can put this problem forward to my professor, I wanted some advice on this.

I have probably forgotten a lot of information, i will add it as i remember:)

Any advice would be highly appreciated.

[Tinstaafl]

Those tabs also house weights, used to move the movable surface's CG closer to the pivot line to reduce flutter tendencies.

[patowalker]

Have you spoken to Paul Dewhurst at Flylight Airsports Ltd.? He knows all there is to know about the SkyRanger and is very helpful.

[kuldeepchana]

Hi,
Thanks for the advice i will try and get in contact with him.

[Pilot DAR]

Though I have no knowledge of the Skyranger, I have some on C150/152. You can look back into the history of the 150M, which has the same tail as the 152. The 150M has a rudder and balance which is 6 higher than the previous models of the 150. This was said to have been done to improve the effectiveness for the rudder. It is worthy of note that when Cessna extended the rudder on the "M", they increased the area of the aerodynamic balance as well, rather than just moving the same balance higher. I'm sure that if you enquire of an operator of a mixed fleet of 150's there will be more insight and observation. Genghis might have some thoughts on this.

Good luck on your dissertation...

[Genghis the Engineer]

Not a lot to add I'm afraid - it's a few years since I had much to do with the type and I'd ask Paul Dewhurst as well.

G

[kuldeepchana]

First of all, thank you very much for the post replies.

Pilot DAR you mention "The 150M has a rudder and balance which is 6 higher than the previous models of the 150."
What do you mean by the '6'. Is it 6 inches higher or longer? and the balance is it correct for me to assume you mean balance horn?

Sorry if im asing silly questions.

[Pilot DAR]

Sorry, my typo, yes, six inches higher rudder and aerodynamic balance on the 150M than earlier 150's. Not a silly question, if I caused confusion!

[Genghis the Engineer]

Kuldeep,

If you are at a university beginning with B and ending with L, and the aeroplane is located near the base of tower C, try contacting a chap called Michael Bromfield within your school - he has done a lot of research into the C150/152 family and should be able to give you something with absolute chapter and verse on the changes between all the models.

(And if you chaps actually finish building the thing this year, it'll be me coming along to flight test the SKR next summer).

G