Two seat helicopter build.

Once I get the cross members welded in, I will need to go ahead and fabricate the landing gear and skids and get sitting on its own legs. I have this set up so the engine gets rolled underneath the frame (between the skids) and hoisted up into position with a transmission jack. Once I find myself in that situation, The engine will have it's own carriage that mates to mounting points on the frame. Once all of that gets done, it's on to the sprag pulley / clutch and the main rotor transmission.
 
Where's the spinny thing on top? :grin:
 
Glad to see you back at this. I have been wondering. What is that frame made of? Will there be any heat treating?
Robert
 
The frame is 6061 square tube. There is no heat treating on it.
 
Got what amounts to the beginnings of the airframe welded up. I parked it over the engine to simulate where that would go.

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Before I can make plans for the engine, I need to get the frame on it's own legs. Today I went to Harbor Freight and bought this hydraulic tube bender to try and bend my 4130 tubing into the shape of the landing gear legs. That silly tube bender just kinked the 4130... It looks like I just clamped the tube in a vice and bent it with a cheater pipe. So, tomorrow I get to return that abomination and go with my plan B.

Plan B is machining out a set of elbows and slipping 4130 tubing inside them to make the shape of the gear legs.

Regardless of how they are formed, I will also machine out mounting brackets and weld them to the frame. With that setup, I can use a set of AN bolts with castle nuts and cotter pins to secure the gear legs to the frame. this will allow the gear legs to flex and have some spring without putting moment torque on the mount points.
 
Awesome project.....I Hope to see it flying one day.

When bending tubing, regardless of it being square or round, I found the best way to get the radius I need is to pack the tube with water or sand and then seal the ends before trying to bend. If you use sand it is usually enough to simply stuff/jam a rag into the ends and then tape over them with some duct tape to secure it in place but if you use water you will need to make the openings water tight somehow, usually welding is involved. Either way will get you a much better more Controllable bend without the kinks.
 
Awesome project.....I Hope to see it flying one day.

When bending tubing, regardless of it being square or round, I found the best way to get the radius I need is to pack the tube with water or sand and then seal the ends before trying to bend. If you use sand it is usually enough to simply stuff/jam a rag into the ends and then tape over them with some duct tape to secure it in place but if you use water you will need to make the openings water tight somehow, usually welding is involved. Either way will get you a much better more Controllable bend without the kinks.

I have been doing some more thinking on the gear and I came to the idea of machining out some 135 deg elbows so the tubes could be simply cut to length and clamped inside the elbows. I know there is going to be a lot of strain on the elbows, so they will need to be made pretty stout. The helicopter is supposed to have a max gross of 1500 lbs. I also have to account for a less than optimal landing in which the helicopter may bounce a little. So, it's completely possible for the gear to need to hold more like 2500 lbs before reaching yield strength.
 
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