Hi Gordon

Nice idea, but I'm pretty sure that's NOT how the Egyptians did it, for several reasons:

1. Wood of a reasonable size was a scarce commodity in Egypt and had to be imported from the Lebanon. Even royal sarcophagi are often made from the most bizarre collection of odd-shaped scraps of wood (often recycled) and dowelled together to form the overall shape. The final smart appearance was created by applying layers of gesso, paint and gold.

2. The distance from the quarries to the pyramids is such that with your 1 in 15 slope a total lift in the region of 100 feet would be needed. Whilst I realise that this would be done as a series of smaller lifts, the overall work would probably exceed than of just dragging the stones (see item 7 below), and that's just to do the easy bit of moving the stones horizontally.

3. Archaeologists have found evidence of earth ramps leading up out of the quarries and on the approach to the pyramids, which is why they favour a dragging-up-ramps interpretation.

4. The slope of the Great Pyramid (for example) is just under 52 degrees. With course heights averaging around 4 feet. That doesn't leave much space on each ledge for a stable wooden structure AND a stone that is roughly the same width as the ledge it has to stand on. Admittedly, it would be possible to leave alternate rows of stones out to form a staircase with double-sized steps, but then the lift per course would increase from 4 feet to 8 feet.

5. Nile mud when wetted forms a nice slippery surface over which a stone can be dragged fairly easily even without a sledge. Foamhenge clearly showed that a stone could be dragged successfully even up a ramp if the friction can be minimized. The mud can be wetted just in front of the stone so that the pullers are walking on dry ground and the hot Egyptian sun dries it rapidly afterwards ready for the next one.

6. The average delivery rate for core blocks (the rough internal ones that comprise the bulk of the mass) had to be at least one every 2 minutes during daylight hours for the pyramid to have been built in the 20 years that the archaeologists estimate. That would require an awful lot of timber trackways.

7. As a general rule of thumb the frictional force involved when two surfaces slide across each other can be calculated as weight multiplied by the coefficient of friction of the contact surfaces (which is a constant for a particular combination of materials). Contact area does not enter into the calculation at all, and therefore (contrary to popular misconception) reducing contact area does not result in reduced friction. In fact, reducing contact area increases the contact pressure in direct proportion and at some point deformation of the contact surfaces will be sufficient to increase the friction. Deformation often builds up when the weight stops moving, which is why it's often difficult to get a heavy object started in the first place. So gravity has to overcome essentially the same amount of friction as dragging and since you have created that exact same quantity of gravitational energy by the work you have put into lifting, you haven't really gained anything.

8. Applying the principle of Ockham's Razor: "entia non sunt multiplicanda praeter necessitatem" - entities should not be multiplied beyond necessity (I know how fond you are of Latin quotes). In other words, the more complex you need to make something, the less likely it is to be the correct solution. Your solution strikes me as too "engineered" to be really likely.

It's a nice bit of lateral thinking and a lovely piece of carpentry, but I don't think you'll convince any archaeologists.