Fokker wheel bearings

[Dogtail2]

I believe the Fokker DVII and Triplane had plain bronze bearings in the wheels. I think most reproductions/replicas have this arrangement too.
Could someone tell me what is the experience with operating with this arrangement. Has it given any trouble re: binding. Has any provision been made to grease the bearings in situ ie grease nipples or does the wheel need to come off. If so, how often? I know of 2 Triplanes that have grease nipples fitted. What about all the other Tripes/DVII's ?

[Makhpiyaluta]

We have the grease nipples on our D VII hubs but once the wheels are coverd you can't reach them anymore. So I take the wheel off regulairy to grease the hubs and axle. We do have the bronze bushings and made spirals in them so the grease is pushed to the centre and won't leak out the sides.
Besides it's much faster to take the wheel of then to try finding the grease nipple through the small hole in the cover.

Willem

[Maxim08]

Dogtail2,
The GWFM has bronze bearings on about 1/2 of the aircraft ie 4 or 5 (others use automotive style wheel bearings and axles). Generally the bearings are only scheduled to be lubed during the annual inspection. Several have grease fittings with long extensions, others have no inside wheel cover which gets by the access problem. If using a grease fitting, as mentioned in the previous post, you need to machine channels in the bearing to distribute the grease along the length of the axle. Make sure that the grease fitting terminates inside the groove! I have seen wheels made with 'top hat' style press fit bearing sections and no groove. Usually there is a small gap between the sections that ends up full of grease with virtually no grease between the axle and bearing surface. I like the off-the-shelf- top hat parts as the flange provides a nice thrust surface and it saves all that machining.
FWIW, the aircraft average about 30 hrs a year so the annual 'pull the wheel and grease' approach appears to be fine.
Regards,
John

[Jim Bruton]

Pete,

My bronze sleeve/bearing seems to be oil-impregnated. I am not sure what else needs to be done at this time or what the oil-schedule is.

Hope all is well.

Jim

[Dogtail2]

Willem, John and Jim,

Thanks for the replies.
I decided to put a grease nipple in the hub. My bearings dont have a spiral inside and are not 'oilite' like Jim's so I'll have to keep an eye on things when the machine becomes operational. (when! ).

There are no axle/bearing tolerances given on the drawings, so Ive set it up by feel. I am aware that 2 Triplanes here have had wheel binding issues prior to the fitting of grease nipples.