Scale Soaring UK

I'm building a new big lift tug and considering my engine options. There's the usual array of 2 stroke petrols, but I'm wondering if anybody runs a four stroke petrol in a tug of that size? I like the 4 stroke sound but they do appear to be quite limited in capacity and grunt. Should I stick to 2 stroke?

Rob

" I like the 4 stroke sound but they do appear to be quite limited in capacity and grunt".

I think you have been locking at the wrong web sites! How deep are your pockets, have a look at https://www.toni-clark.com/index_en.htm and look at the Kolm and Valach 4 stroke engines .
Also depends on how much towing you are planing to do .

Thanks for the response but those engines are way too heavy and oversized for a big lift.

The ‘Big Lift’ is only 88” span, so not so big by tug standards - people seem to fit 35cc petrol 2 strokes. I guess a 50cc 4-stroke might be fine, e.g the Kolm: http://www.kolmengines.com/portfolio-item/ez50v4/ , or this 38cc 4 stroke: http://www.justengines.co.uk/acatalog/N ... ngine.html

Simon

Thanks for the response. The NGH is what led me to ask the original question, it looks like a reasonable option but I fear it would end up having the same power as a 26cc two stroke and hence be underpowered for towing. I already have an ageing big lift with a DLA56cc 2 stroke which has worked really well but I think the engine has a big end fault and spares seem to be unavailable. The problem with the kolm is that it's much heavier than the DLA and would need lead at the rear to balance the model.

It depends also on the size of gliders you want to tow. The 88" Greenley glider tug I have is powered by a Zenoah 62, will happily run all day and tow upto 6mtr gliders.

A four stroke will always have less power, size for size compared to a 2 stroke as it has 2 extra strokes per power stroke...

I've bought a saito 4 stroke petrol radial for my latest tug project, it won't have as much grunt as the DLE I've used previously but it will sound and lok magnificent... Also significantly more expensive.

If you're doing a lot of tugging, get a DLE and fit and forget, a 55cc will see you for most towing duties.

I've just adapted a Yak aerobat which has a 55cc DLE to tow, it works really well, I'm chuffed to bits.

Ell.

I think I'll probably have to give up on 4 stroke and go for the DLE55 like you suggest Elliot, although I'll probably regret it when I hear your new engine.

I'd already seen your Yak modification post and my own Yak will be modified in a similar way shortly! It's only a 26cc but it'll still be useful for towing smaller gliders as well as aerobatics.

Rob

I think that's probably the best decision, unless you're going radial... They're hard to resist

Best of luck with the Yak, I think you'll be pleased, if you put your tow hook something like where mine is, the attitude isn't altered on tow, it's a hand off job nearly!

cheers, Ell.

We Fly a hangar ( Pawnee with a DA 120 up front plenty of power for pretty much any thing on behind!