GY80 Gardan Horizon Owners/Pilots ?

[Flying John]

Are there any other GY80 owners on the LAA forum who may be able to help me.

I am trying to get some information on a modification of the brake system to incorporate Cleveland Discs and callipers. I have seen the modification on some GY80's in the past, but am trying to find some data regarding how the mod was done and approval (if any) that was required (ANN or minor mod with Regional CAA approval)

Any help appreciated

John
+++ --- still waiting for transfer to Permit --- +++

[dave mackay]

Hi John,

Sadly it seems that making the Cleveland brake conversion on the Horizon now is extremely difficult from a certification viewpoint. You can buy a conversion kit from the APAG (Gardan owner's association) in France, that gives you a pair of sleeves which fit over the existing axles and also a pair of brake mounting plates. You then have to source the brake units and wheels and then locally manufacture the required pipes and also cut back the skin from the under-wing apertures so the larger wheels fit inside.

Problem is that this is an EASA certificated aeroplane as you know and therefore any such work would be considered a major modification requiring design work from a Part 21 approved design company making it prohibitively expensive. Particularly frustrating as there are several Horizons going about as I type with the Cleveland brakes but those were all approved as minor modifications by the CAA many years ago. I have had quite good success overhauling my Gardan brakes and they now work well enough that I am no longer considering the Cleveland modification (for the moment!).

If you find out anything which helps towards certification of the mod please let me know as it may be useful for the future.

Dave
(G-ATGY)

PS, I just bought another written off airframe (G-ASZS) as a source of parts!

[rogcal]

If it's of any interest, I had the floating discs on our Horizon (G-BKNI) duplicated using stainless steel back in the early 90's.

The mild steel discs were a real pain due to the constant build up of corrosion between the kidney shaped pads and the discs which in turn led to decreased braking efficiency and rapid pad wear.

The braking efficiency of "Bikini" improved dramatically following this minor mod and remained so till the end of her flying days.

We also overcame the problem of sourcing pads by buying a large block of brake material and making our own on a band saw.

Of course it helped to have a "tame" engineer who happily signed the work off!