Landing Gear Choices

7/2/2009

My seat pans are now trimmed and the edges polished. I will fit them once paint is on the tubes. I have a feeling getting the aluminum bent over the tubes and riveted down is going to be a real pain...

I have also been busy making and welding on bits here and there, such as cable bulkhead brackets and throttle/mixture cable attach tabs. I also decided to go back to the rear pilot seat with aluminum sheet instead of fabric. This will give me much better post-access for maintenance. So I made new fuseIage formers from 3/8 tube using a large gas bottle as a forming tool. To achieve the correct shape, I temporarily sat the turtledeck in situ, then traced the contour down the side of the fuselage with a strip of 1/16 ply. Formers are now welded in.

Fuselage Rotisserie

Next I made up a fuselage rotisserie. Those who have built with and without one know the easier route :0). I purchased a sacrificial engine mount from Harbor Freight for around $35. I needed to raise the mount so it's center point matched the center point running through the fuselage and alter the mount angle to 90 degrees (they come angled, slightly). So I chopped the upright in half and hammered in some 2x4 lumber on each end, then bolted on a pair of 1/8 steel angled plates to bring it back to vertical. The tail stand is from 2x4s studs, I will need to put up a couple of pics rather than try to explain how I made the tail end.

The rotisserie is now ready, but I cannot use it yet since I have the fuselage inverted and clamped solid to a wood frame complete with concrete bags as ballast, while I mess around with a jig for the potential idea of using RV/Wittman style round spring steel landing gear.

RV Style Landing gear

I am looking at the possibility of using spring steel landing gear (Wittman Tailwind and RV's) as opposed to the traditional bungee gear, or the Groves aluminium gear. My reasons for this deviation is i) sleek modern look (which is the look I desire) ii) less under-wing turbulence iii) less drag. However, the penalty is more weight compared to bungee gear. So, one has to compare the trade-off between looks/heavy/but streamlined versus traditional/lighter/bulky.

I initially had a spare RV7 leg that someone loaned me for mocking-up. I was kind of hoping this leg would be darn close to my geometry, but as half expected, that was too good to be true, but it did get me close regarding visualization. I then discovered two significant leads... i) the EAA website has a design spreadsheet dedicated to this type of gear design and ii) I discovered the contact# for the company that make the spring gear for RV's - and they do custom sizes.

According to the spreadsheet, the proposed spring gear will be heavier and slightly thicker than the RV7 leg, and will have 1.5" axle dia. Currently, it seems the RV gear is very close in weight to the alum' groves type gear when comparing apples'. However, I suspect the RV style gear will top out 2 or 3 pounds heavier than groves when all is done. I will eventually publish the weight breakdowns.

More to come on this saga.