1:2.5 Scale KA8 Upgrade

[John Mcnamara]

Hi all,
I know that much has been said about these far eastern models over the years. I am just getting back to mine to finish it off.
The work that has been done so far is to build a proper double spar system into the inner wing panels with full lenth hardwood caps at maximum depth and also in front of the TE positions. Each are infilled with vertical grain balsa. These will not fail easily, but I remain concerned regarding the wing joiner tubes in particular. Whilst I have added reinforcement to the tubes that carry the aluminium tube joiner, the tubes out towards the outer end of the panel look particularly vunerable. I have not acted yet as I do not wish to added weight outboard, but I wonder what the experiences others have had? Need I worry about these outer wing tube positions pulling out of the wing?
John

[Barry_Cole]

John,
Geoff Crew has done this mod with great success. I am sure he will answer this. I will give him a prod.

[John Mcnamara]

Thanks Barry,
I plan to change the nasty poor quality carbon tubes for the wing tips for some better ones too. The fuselage has had a number of mods included sheet the front fuselage in 6mm ply, rebuilding the wheel box, adding strip hardwood to the edges of all the formers etc. The fuselage and the main wing panels needed many of the joints regluing but the wingtips didn't. I have not paid attention to the empenage yet.

John

[geoff_crew]

Hi John,
I've not had to reinforce the outer carbon tubes on either of my K8's (one with electric motor and one without) and have not (touch wood) experienced any problem with the outer wings. However, it may well be worth making an additional end plate at the retaining tube ends in the main wing as i have had one of the outer wing tubes push through one of the end stops. From recollection i did make additional rib tube end supports in the main wings along with adding additional 12x6mm spruce spars capping them off with lite ply web plates. Both of the fuselages were starved of glue and were reinforced with 1/32" ply on the formers from the nose through to the rear of the canopy. I also strengthened the bottom keel/spine from the rear of the fuselage up to the wheel box area. I believe i also raised the front of the tail plane tail plane approx 4mm in order to reduce the incidence from 6 to about 2 degrees.
Hope this helps,

Regards
Geoff

[John Mcnamara]

Hi Geoff,
Yes, my fuselage and main wing panels were also starved of glue. Strangely the tips were much better built. I think I will add some reinforcement to the tube bearing ribs in the outboard end of the main panels and the tips. just for peace of mind.. I have heard about the decalage and I will make a wedge when I get to sorting the tailplane.
Thanks for the input Geoff.
John

[Euan Galloway]

John ,
I have modified six sets of the inner panels and had no failures so far ? never did any work to the joiner tubes or tip panels .
Apart from glassing the front canopy area and adding liberal amounts of glue the fuselages again have had no issues
Mine have flown with electric and turbine power and have been given a good thrashing off the slope including bunts .
Still think they are excellent value if you accept the issues and are prepared to do a bit of balsa bashing .
I have spent several times more on European moulded scale gliders that also present build and quality issues .

[John Vella]

Euan, "turbine power and thrashing and bunting " a K8 boggles one's mind !

[Cliff Evans]

It simply is not a glider anymore!

[Euan Galloway]

So not every ones style of flying then ? , still not got the hang of flying the tug and my glider at the same time so I do lots of slope flying and yes i enjoy a bit of aerobatics with most of my models and certainly proved the wing spar upgrades work .
Turbines have been fitted to many different full size gliders for self launch and i don't see the problem with doing it .

[Cliff Evans]

Each to their own, I flew jets for four years, thoroughly enjoyed it. Now I fly nothing but gliders and get more enjoyment from them than any other discipline I have flown. I started the hobby with Gliders and will probably go out flying them. Much the same as nappies really!!