Scaffolding poles + old VW bits + Rotary engine....

[PhillipM]

And just in case you hadn't had enough of half finished wing pictures yet....another rear element skeleton built up awaiting foam + skinning:



Also decided to draw 'em up properly in CAD rather than just a skin - means I can work out where best to put the slot gap spacers then. Hoping to get away with a single centre one just to keep things where they should be:

Edited by PhillipM on Monday 11th July 21:26

[PhillipM]

Miles away from an accurate model (or loading scenario, need to model endplates and the skins first, never mind the bonds, fillets and foam), but just a quick check on the skeleton (which is much less stiff than the built up wing) shows the overall deformation is acceptable as is. So probably loose the slot gap seperators and just have a few elements on the pressure side to stop spanwise flow instead. Should be enough by themselves to stiffen the thin trailing edge.

[threadlock]

PhillipM said:

TL:DR - New P/S pump. Works better than old pump. Is shinier.

[PhillipM]

I could have had a much shorter thread doing that....

[PhillipM]

Hmm, I need to find someone with some spare carbon.....this is too shiny and tempting...

[Huff]

... even if you did, the first thing you'd do would be chop a hole through the most essential structural spar, strut around it, and install something bigger/shiner/new-'essential' in the middle of it with a TIG welder and some bolts...


Please don't stop updating this thread. Love it!

[PhillipM]

Well, it'd need some slots so we can run the exhaust through the spars and blow the wing...where's my grinder gone...

Edited by PhillipM on Thursday 14th July 21:26

[PhillipM]

Huff said:

... even if you did, the first thing you'd do would be chop a hole through the most essential structural spar, strut around it, and install something bigger/shiner/new-'essential' in the middle of it with a TIG welder and some bolts...


Please don't stop updating this thread. Love it!

I was only intending on stopping the thread updates as I was expecting to end up caring full time for my parents for a while, unfortunately that option got taken away from me, so I'll be posting rubbish here for a while yet - anyway, back in the vain of your first paragraph...

1. Dry sump pump has the endfloat way out of spec now it's bedded in, so that's off and will be stripped and shimmed to suit shortly.

2. Wasn't very happy with the dry sump drive belt as it had a tendancy to wander back and forth over the pulleys - some of it is probably the end float but it looks like one of the pulleys isn't quite round either.
So in our usual style, instead of leaving alone something that's working fine, or tweaking it, the whole lot has been removed and some fancy new herringbone-cut gears are going on next week that give a nice self centring effect, as well as quieter drive with less vibration into the pump (as there's smoother engagement from the helical teeth), just need to make the drive flanges and mountings on the lathe.

[PhillipM]

Just in case you weren't fed up of seeing wing pictures yet....endplates and gurney, etc:




There's a bit more refinement to come on the endplates yet, trying to get them as effective as I can but I'm limited both by space and by the mountings so I can't have them as deep and as far back as I'd like. Think some gurney tabs on the rear edge might help so plenty to try out once it actually goes on the car.

[PhillipM]

I think a stiffer endplate may be required....



Also. Wing may not be effective at speeds over 250mph. Must remember to back off a little in 5th....

[leglessAlex]

How accurate do you expect these simulations to be? Do you adhere to them exactly or do you use them to get an idea of the minimum strength you need and then overbuild it slighty?

[PhillipM]

No, just a guideline, I never assume anything is accurate when it comes to sims

However, my wings in reality are stiffer than the model anyway, as all the joints are filleted and the skins are supported by polyurethane foam.
They're more than strong enough, it was more the stiffness I was wondering about - I just needed to make sure the deflections were low enough and fairly well matched between the elements (as they're not the same size or loading).

The other thing is it lets me shove endplates sideways, etc, to simulation an impact with a tree or similar and make sure everything stays elastic (or at least that the endplate bends around the mounts first).
There's some gurneys to go on the rear of the endplate that should help out there.

New PAS pump is finished and in, old relegated Peugeot pump sulking in the background...



Mounting bracket - think Ed got a set of holesaws for Christmas...

Edited by PhillipM on Sunday 24th July 20:31

[PhillipM]

And probably as far as the endplates will get refined - at this point they're still easy to make, rapidly into diminishing returns in the case of time vs benefit otherwise:

Edited by PhillipM on Tuesday 26th July 01:12

[PhillipM]

One for old Citroen fans - the new drive system, soon to meet the lathe for some serious weight reduction and some aluminium centres - shouldn't have any issues with any mud/stones that get through the seals either with these!
They also run a lot quieter with less vibration/stress as an extra bonus.



And of course, can't go without more wings.....now they're red. Red cars are fastest, well known fact. You knew it was going to happen:





And no, your eyes aren't going, it really is fuzzy - it's the weave from the cloth.

Edited by PhillipM on Monday 8th August 21:49

Edited by PhillipM on Tuesday 9th August 17:00

[PhillipM]

And an ode to our lovely member Huff, who knows me too well.....can't be leaving those pulleys like that can we? Where's the lathe gone...

[Huff]

haha! Can't leave well enough alone, eh.

I might be of short memory but I'm trying to work out what those gears are now for (even before they need a reason to be altered )

[PhillipM]

It's even worse, those gears are a replacement for the other ones we already have that have only been used for a couple of hours to bed the engine in/mapping. And that's before they get altered again

That's 3 revisions in a total distance travelled of about 6 feet...

[Huff]

Really interesting though: double-helical gears- the ideal low-noise with zero-net-thrust format - yet the teeth are offset, doing-away with un soupcon of the raison-d'etre.

Only a Frenchman could come up with that! What are the donor gears from/designed-for?

[PhillipM]

The offset teeth reduce the belt noise/vibration further, although you'd imagine it must introduce some slight torsional vibration instead - mind give the leverage and the teeth in mesh at the time it'd be tiny.

They're from an extruder that runs from a tractor PTO, albeit we're running shorter belt, but they're fairly common on belt drive EV's, etc.

[Huff]

Interesting - and thanks

Actually, I'd be interested to know how such things are formed in the first place - obviously these gears can't be simply hobbed, given the overlapping tooth ends; are they sintered/powder metallurgy ..?