Props and CofG
My prop is due for a Notice 75, so I've been having lots of propeller chats to various folk about 75's and overhauls and generally thinking about propellers quite a lot over the past week.
So, my gardener watched me struggle across to the workshop with my c/s Hartzell in my arms on Saturday. He remarked that it did look quite heavy!
I explained that it was off to the propeller hospital for a check-out at a cost approaching two grand, once I'd made up a crate for it. He appeared interested, so I then explained to him that the blades move and that it is quite a complex thing compared to a fixed pitch wooden prop.
He asked what would happen if a blade came off and I said well the imbalance would probably tear the engine out of the mount - and if that happened the aeroplane would develop the gliding characteristics of a house brick and that he'd not be paid ever again by me!
So.... yesterday, I'm back in the hangar and I need to move the aeroplane to position the engine under the hoist as I am about to remove it to perform various maintenance chores and install my new hi-comp pistons. The tailwheel was supported on a modified trestle and I attempted to lift it off. I can normally do this with one hand and with a bit of effort, hold it up whilst I pull the trestle out with my other hand. Well, I huffed and I puffed but yesterday I could barely move it - I eventually managed with two hands and kicked the trestle over so that I could place the now incredibly heavy tail back on the deck.
I took the engine out and the engine mount which needs painting and as I plan to renew the bungee cord on the main gear, I manually lifted the front of the aircraft to gauge the weight (with a view to supporting the a/c from a rope block and tackle as the 25T hoist was still supporting the engine, albeit that the engine was resting on a couple of trestles, whilst I get around to welding a stand for it or locating the one that I made 9 years ago!).
Without too much effort I had the main gear wheels off the deck so I feel quite comfortable using the lighter block to support the fuselage.......
So this started me thinking, without wishing to do any major CofG calcs, IF I lost the prop, the Cof G would be so far fwd that I don't think that she'd fly, BUT if I lost the prop and the engine the CofG would move rearwards and quite possibly be a safer scenario!
This obviously is hypothetical and I intend to renew both the engine mount bolts and the engine bolts, too!!
Your thoughts?
(I am aware that I do have a very vivid imagination and I ought to get out more!! )
Stik