Lifting completed Bearhawk to change undercarriage bolts

[Battson]

I am looking for *tried and tested* ideas for lifting one leg of a four-place Bearhawk.

I need to change my gear bolts and I want to avoid lifting by the wing if possible, which is what my IA is recommending. This need to be a method tired and tests on a four place with wings and engine installed (finished plane ideally).

I have used an engine hoist before, lifting off the engine mount. I wasn't entirely happy with this method, but at least the gear legs were still attached in case things went wrong. I do have access to an engine hoist and a small overhead crane, both strong enough to lift about 300kg but not much more.

I wouldn't like to be under the plane hauling on the landing gear with one leg entirely removed, that said - I guess I can change the bolts without fully removing the leg if I am careful, one bolt at a time. But I digress!

Tried and tested lifting methods gratefully received. Thanks all!

[bearhawk2015]

I’ve done the same as you with the engine hoist several times with out incident. When I do the swap to and from floats I use an overhead chain hoist that is connected to 2 straps, each strap goes around one side of the engine mount and up to the hook on the hoist. I then tie a rope to each strut where it attaches to the wing and then tie the other end of the rope to something heavy on the ground. This is just to keep the plane level when I’m lifting it because one side is always heavier due to one tank having more fuel in it. Hope this helps.

[bearhawk2015]

Also when doing this make sure the tail wheel is somehow secured so that it can’t pivot or roll.

[Battson]

I’ve done the same as you with the engine hoist several times with out incident. When I do the swap to and from floats I use an overhead chain hoist that is connected to 2 straps, each strap goes around one side of the engine mount and up to the hook on the hoist. I then tie a rope to each strut where it attaches to the wing and then tie the other end of the rope to something heavy on the ground. This is just to keep the plane level when I’m lifting it because one side is always heavier due to one tank having more fuel in it. Hope this helps.

Thanks for your feedback.

The only challenge with the engine hoist technique is one of the hoist legs wants to sit right where the bush-wheel goes, no matter which way I face the hoist. It's a minor annoyance at worst.
Did you find the same?

[bearhawk2015]

I do remember shimmying the lift around to find just the right spot so that it cleared the wheel. I still thought it was safer than lifting a wing, which I have also done with almost disastrous results.

[zkelley2]

I do remember shimmying the lift around to find just the right spot so that it cleared the wheel. I still thought it was safer than lifting a wing, which I have also done with almost disastrous results.

Almost like this?

Battson, most people up here run lift rings all the time. Makes gear swaps easy and in the case of an oops, but not complete destruction, the helicopter ride doesn't total the aircraft. In leui of that maybe check out Bogert Aviation. They have some interesting ideas.

[jaredyates]

If you don't want to lift at the wing, how do you feel about resting on the wing? Could you jack it up, install a prop under the wing, then lower it back down?

[JimParker256]

Or lift it with the hoist, then place a padded saw horse under the fuselage? This is what the Grumman gurus do at annual for the 2400 lb GW Tiger so they can pull both wheels at the same time, and still have someone working inside the airplane. I did an owner-assisted annual, and the airplane sat that way from the start of the annual until just before the final walk-around inspection (for panels, etc.).

The saw horse is specially made using 2x6 with two fairly large trapezoid-shaped plywood panels, each attached to the top and side legs of the saw horse, and two rectangular panels across the front and back. Glue and lots of screws holding it all together. That plywood panels go from the top maybe 2/3 the way to the ground, so the sawhorse legs are super sturdy. Make it as tall as you need to fit where it needs to go, and pad the top accordingly.

[Battson]

Almost like this?

Battson, most people up here run lift rings all the time. Makes gear swaps easy and in the case of an oops, but not complete destruction, the helicopter ride doesn't total the aircraft. In lieu of that maybe check out Bogert Aviation. They have some interesting ideas.

Yes I am keen on the idea of lifting rings for easy recovery. I often think I should get some made up and installed. That said, when we crashed we ended up upside down, and it was easier to lift it upside down!

One lifting strop on each wing strut tie-down point (with a backup wrap around the strut) and one strop onto the tailwheel. We lifted it out using a B3 Squirrel into a grassy field and then set it down (still upside down), then freed the wings and lifted the whole aircraft using the tailwheel line onto the helicopter. We flipped the plane back onto the main wheels, doing a nose stand in the process, with people holding the wingtips to keep it balanced on the nose while the heli flipped it over. He left it balancing on the nose and the main gear. It works great provided you have an expert helicopter pilot. Then we just pulled the tail down by hand, it bounced hard but the tail spring soaked it all up without any fuss.
We did practically no bonus damage during the recovery, which is the perfect outcome from such a bad situation.

[Mark Moyle]

These are permanently mounted on my Pacer and are attached to the wing root at front wing spar. Use an overhead hoist and spreader bar... I also installed two handles on the lower longerons right at the cluster for the jack screw.

[Glenn Patterson]

We used an engine hoist in February to help switch from wheels to skis. We had to change the gear leg bolts to longer bolts to hold the ski bungee attachments. It was a little tense doing it on snow but it worked with careful manoeuvring to get around the 26" Tundra tires. We use a short industrial sling around the top engine mount that is a Continental Bed mount so there is a good corner in the tubes to keep the sling from moving. We had to reset it a couple times as the sling stretched out to shorten the set up. We keep the hoist fairly close to the mount so there is less ability to swing. We blocked the wheels so it could not move and lifted it just enough to take pressure off the leg. An old shop bolt was used to drive the gear leg bolt out and hold everything together. The new longer bolt was tapped back through the opposite direction to push out the temporary bolt . That gave us the longer bolts for the ski bungee attachments. It went fairly easy and was not the fight that we had expected.

We also made a spreader bar that we use to bridge the gear legs so we can put a motorcycle jack under the the spreader to lift one side or the other to get a wheel off the ground. The spreader with the jack makes it easier to lift the airplane to swap out tires for skis. We don't have pictures of the spreader bar in action but I will take pictures on change over. The spreader makes tire work easier.

[davzLSA]

hi Guys, Has anyone built in hard points for jacking during the build process? This is something I have been thinking about doing with my LSA, I know it is a little extra weught but it may be worth it when needed?

[svyolo]

How about a modified tie down ring that is secured in position. Then use a shop crane to push up, instead of pull up. It would push up from below.

You wouldn't want it to slip.

[SimonNicholson]

As you know Jono, I am fitting my Bearhawk out for floats. I am making some lifting eyes out of s/steel like they use on the cubs and have them permanently fitted to the spar bolts.

[Oriwha]

Hi Battson, all you need is to come visit my build and we will do the change while you are here. Lifting device is a 12 ton digger, using 5 ton strop on engine mount. Real easy.
Dave Devine.