Recent content by EdBundy

Hi Terry Thanks for the info. We are indeed making the gearbox casing from aluminium, for mass and heat transfer purposes. We have sized the bearings to give appropriate life and unfortunately, for splash lubrication to even be possible, the oil level will completely cover the lower rolling...

Good day to all I'm busy designing a small 12kW reduction gearbox and due to space constraints will have to rely on splash lubrication. Are there an rules of thumb to adhere to regarding splash lubrication which you wise folks would mind sharing? The gearbox is a 4:1 reduction box...

Thanks for the insights, but the question remains - to what do I qualify it? Usually we qualify our designs to FAR29, but this is beyond the scope of FAR29 so I'm looking for some other supporting standard, i.e. something our CAA would accept. Myself, the electrical designer and one of the...

Hi Heli vibration is a bid of mixed basket to sort out thanks to the nature of the beast. Perhaps you can share a bit more info on the problem, i.e. the mass of the equipment, are the connections to the skid rigid, what kind/size/layout the equipment is, etc. In my experience shock mounts are...

Tienne, Do you output an .f06 file as well? This is the manual way I usually look for problems. Open the f06 file (it may be huge, something like LTFviewer comes in handy) and search for the string "fatal". It should tell you why fatal errors (which cause the analysis to stop) occur and can...

Hi all Thanks for the insights - gives me some food for thought. That being said, there is such a miriad of design standards and testing procedures out there that one would think at least one of them deals with allowable QD forces. Having the connector break on the seat is not feasible since...

Hi all Does anyone on the forum have any experience or information regarding quick release (quick-disconnect, or QD) connectors? We're integrating a helmet system into a helicopter and for emergency egress purposes fitted the helmet loom with a QD connector. The problem is that we cannot find...

Good day all Thanks for the valuable input. To clarify somewhat, the lug is for the launcher which is attached to a carrier, and not to the EMRU directly (14" btw). RB1957, we've used non-metallic washers in the lightly-loaded out-of-plane direction, however in-plane the loads are such that...

Hi Kenat, tbuelna The literature I have covers fretting, it's causes, mechanisms, and how to design to avoid it, however due to legacy and external design constraints these cannot be avoided. The lug is on the launcher and not on the store itself, so every "launching" event will put a severe...

Hi rb1957 That seems the first prize :-) But alas, the structure is to be mounted on a helicopter, which will definitely induce some vibration at the interface, irrespective of load direction... Thanks, Ed

Good day I've got a question regarding a reference for fretting corrosion factors used in fatigue analysis. We're analysing a launcher structure, and thus far we've been using an old Aerospaciale reference for the factors (based on bush/no bush, hole and pin tolerance, finishing, etc.)...