The Jabiru 3300 cowl has a lower and upper cowl, split horizontally. Removal of the lower cowl is easiest as a 2-person job so one person can hold the cowl while the last retaining screws on the fuselage are removed. I've done it solo most of the time by perching the cowl on a stool or adjustable work stand, but it is balanced precariously at best! Once the cowl is removed, the stool or stand is definitely not stable enough to leave the cowl on it and I'm always looking for a safe place to temporarily store the cowl during maintenance.

It occurred to me that some sort of hydraulic lift and cradle would be the ultimate way to remove, hold, and re-install the cowl as one could very precisely position the cowl for installation and also use the jack to drop it a few inches during removal so it will clear the prop spinner backplate.

Since I already had a motorcycle, I found a Harbor Freight 1500lb motorcycle lift on sale. Using the 20% off coupon on top of that, the jack was only about $60-70 as I recall. It doesn't lift high enough for the lower cowl to sit directly on the jack's padded rails, needing about a foot of additional elevation, but I wanted a "cradle" to hold the cowl that was more padded and shaped appropriately, so I planned to either build a frame or cradle that could be attached to the top of the jack to bridge the additional 12" or so that I needed ... it would obviously also be more secure with a shaped cradle, too!

At first I had ideas of making something up from PVC or steel tubing, etc., but then it struck me that a common $8 Rubbermaid storage bin, appropriately shaped, would be ideal as the cowl is very light and the support needn't be very strong and the top rim of the bin could be shaped easily since it was plastic. I experimented and found my wood burning kit's hot knife cut through the plastic easily and used that to shape the top of the bin. I only had to trim one side of the rim in a shallow depression to hold the cowl and left the other side untouched. I padded the areas that contact the cowl with foam pipe insulation held by zip ties. 

I did have to cut-out the jack's front transverse frame so it would clear my front wheel enough to get the cowl into position. Looking at how beefy the jack is built, I really don't think it will weaken it significantly even with my 500 lb motorcycle on it, but figured I could either make a safety chain to clip across the front when using it with something heavy or perhaps a temporary crossmember with removable pins. I also had to make a cut-out in the bottom of the plastic bin so it would clear the plane's tire.

I used a long bungee to hold the bin/cradle on the jack and a short bungee on the oil cooler intake to help stabilize the cowl. It is extremely stable and works great and makes 1-person removal a snap! It's also handy that when the cowl comes off, you can just leave it on the jack during maintenance and not worry about it falling off!

Here's some pics:

I realize a 1500 lb capacity jack is waaay overkill for this purpose, but it only took me about 30 minutes to modify the plastic bin and I've got a nice jack for my motorcycle, too!

John

N750A

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