Cloning Volvo IPS Drives!

inkaboat · 16-03-2007

Taking the discussion further regarding large MTB's, I thought it might be a good idea to mount the electric motors vertically on top of my own version of a Volvo IPS drive. For those unfamiliar with the concept, Volvo has 'reversed' the stern drive and the propellor faces forwards, clear of the drive pod. Huge increases in efficiency and speed are claimed, and who can blame us model makers if we take advantage of their expensive research! I just need to machine up two alloy drive legs which rotate around sealed rings set into the hull. One servo would steer it, using an Ackermann rig a la automobile to get the inside prop on a tighter radius than the outer. It's not scale modelling, but what a lot of fun! Anyone got any thoughts? All will be gratefully received.
John

**Bunkerbarge** · 16-03-2007

Volvo do not really have the market on such equipment, forward facing pod drives have been used on full sized ships for some time now and have been quite common on large cruise ships for a number of years.

The idea of rotating a drive and thereby doing away with the rudders and aft thrusters is also becoming more and more popular however there have been a number of failures which have put off the less adventurous companies.

One of the most sophisticated arrangements is as found on the QM2 which has two fixed pods and two azimuthing pods making her very manoeuverable and relatively independant.

Diesel electric is almost compulsory for modern cruise vessels so utilising this configuration with pods is a very flexible propulsion system.

I saw an article in a mag only a few months ago where someone had fitted two pods removed from these tiny chinese toy subs to a revel model of the QM2. Unfortunately they had fitted them the wrong way around so they pushed as opposed to pulled the ship but they still worked very well.

Making a model azi-pod would present quite a few challenges, mainly as regards the seal with the hull, but you would walk away with most steering trophies and if you wanted 360 deg you would need to supply the power through sliprings.