I said above
It's like a big powerful but lumbering truck - tons of grunt, fast in a straight line but without sprint accelleration, fairly unmanoevrable.
Far faster than a solo on the flat, for a given amount of effort, goes like stink downhill, pretty quick up long shallow drags.
Just a bit of an effort on steeper stuff, but that does get a lot better with practice, as you learn to work together in time rather than fight one another - first time you try to honk up a steep hill you'll spend more effort on balancing the thing than climbing, but it gets better.
I fear that may be it - you're probably right to ask what is the technique.
It is balance and timing, working together rather than against each other, and it only comes with practice.
Your friend may be fit, but you say an inexperienced cyclist ?
- and perhaps, other than with Tom, you're a not that experienced a tandem captain ?
Mrs wrx is far less keen a cyclist than I am, which is the reason we got the tandem - we could go out together and actually ride together, rather than me being off in the distance and frustrated about going so slowly, her being frustrated and demotivated by flogging herself silly but not keeping up.
Out on the tandem, I'm pretty aware of her on the back - she's fit enough, she runs a marathon every April, but isn't 100% balanced and fluid on the bike. She 'pedals squares', stamping down in-turn with each leg rather than smoothly spinning the pedals. And she fidgets around, wobbles the bike a bit as she shifts her weight.
None of this really matters, because I'm a few stone heavier and I can smooth it out...
For climbing, she's got excellent stamina but I can pump out a lot more short period watts.
So if it's one of those little brows you take a run at and power over, I pile it on and pull us over it, then I can ease off a little and recover as she keeps our speed up.
If it's a long drag, we work together and get in a rhythm, and this is what we generally do on really steep stuff too - we let the speed drop off, drop down into a low gear and spin up it : we've tried powering up it, honking out of the saddle, but it is difficult.
(I admit at this point that we live in Cheshire and I tend to avoid finding really steep stuff on the tandem - we are supposed to be out enjoying ourselves together and I'm afraid of making it 'not fun' if it gets too hard...
I'm sure if we ventured across to the Peak District or North Wales and found ourselves some steeper stuff, we'd be forced to get better at getting up it !)
However, I've also been out with a male friend who's a couple of stone heavier than me on the back and that really was entertaining - the bike was twisting around with him bouncing around on the back, shoving the power on and off, etc.
We were going pretty quickly but I really was having to work for it - but it felt like more effort was going into balancing and controlling, trying to smooth out him on the back, rather than leg-powering the pedals round myself.
We didn't try any steeper hills but I suspect that might not have been fun at all !
So I think it is just technique - smoothness and balance, working together in-time rather than against one another, and it comes with practice.
'Less is more', perhaps - put less effort in, but keep it smooth, and it goes quicker.
What I'd really like to do is try a track tandem at the velodrome.
Smooth boards and banked bends, find that smoothness and efficiency with a partner and I bet you can get some quite extreme speeds, but all flowing beautifully.
