Added • Support for KSP 1.2.2 to ``1.3 , removed ICE Wheels, now add a module to make any stock wheels use the ICE vehicle engines as required - see changelog/KSP forum for ICE for further instructions.
Added 1.0.5 • Support for KSP 1.0.5, changed some engine output variables to conform with KSPs re-worked drag/lift code.
Added 1.0.3 • Support for KSP 1.0.3, fixed bug - no thrust on air-cooled engines.
Added 0.90 • Support for KSP 0.90.
Added 0.25 • Support for KSP 0.25, minor re-balance for heat-up rates.
Added 0.24.2 • Naval Landing Gears with grapple code. (not perfected yet but it's in!)
Added for 0.23.5 • Vehicle Engine • Vehicle Transmission • Vehicle Wheels : AT and Performance • New Liquid Cooling Radiator • Liquid Cooled DB605k
Newly added for .23! • tweaks in the hangar! • basic per-engine throttle • other optimizations.
The Basics:
1) add the engine to your favorite plane. (it needs air intakes and fuel just like a stock engine).
2) on the runway a) apply brake b) throttle up about 20% c) right click engine and click auto-start
3) if you're lucky it starts and runs! keep idle steady till the temperature reads over 60c
4) prop pitch can be changed between: forward (1) reverse (-1) and neutral (0) - yes I realize it's a fixed pitch prop on the model, but this is for user convenience!
5) take off and fly as normal!
6) if the engine highlights red you are over-revving it! Back off on the throttle or risk damaging the oil, damaged oil is bad news, the engine could last 2 hours, or 10 minutes. see more below on Over-Revving.
The not so Basics:
Wear and Tear! - before every new flight with the same aircraft, have an intelligent Kerbal inspect the engine for issues. If something seems damaged he can perform a job to fix it. The longer the engine runs - the more worn out it will become, and as it does it produces less power.
note: some jobs require the Oil station, or the Repair station.
Over-Revving! - If the engine turns red while operating, it's over-revving. Back off on the throttle a bit. This usually happens while diving. Prolonged over-revving will likely result in oil failure, then excessive oil pressure and then finally a broken engine! treat her like a lady! 
The WW1 engines are a perfect match-up for Snjo's WW1 bi-plane parts:
WW1 bentley BR1 - 9cyl radial engine - tune it in the hangar!
WW1 engine now added for the German plane! this is a 9cyl rotary, but the model has it as a radial for now I will change it!
Release 1.2 Engines:
WW2 based DB605 k variant (k for Kerbal you know!) this is a two-stage supercharged high power liquid cooled engine, fly like the wind!
4Cyl Vehicle engine - really just the beginnings - you need an engine, a liquid cooling radiator, transmission and wheels to use this on your vehicle, slap it all on something and tune it up however you like.
Generator - use this as a generator to power anything within 30m! or simply put it on a small vehicle to re-charge battery driven vehicles.