Diesels

Having decided to build some (British style) combat wings because of their crash survivablity I purchased a new MVVS 2.5 diesel and a secondhand Russian Oliver Tiger replica.

I intend following the running in procedures given on the British Nostalgia Combat site for the MVVS.

The guy who sold me the Ollie told me that it has a new piston/liner by one of the UK engine tuners (and british bearings) and that it's 'been flown twice' - how should I treat this engine - if I follow the '4 minutes rich and undercompressed then 1 minute normal compressed and lean' rule and if the residue is clear then can I take it the motor is run in?

What fuel should I use for running in - I have available from Model Technics

Ether/Kerosene/Castor/Nitrate mixes of (d1000) 35/35/28/2, (d2000) 30/43.75/24/2.25 and (d3000) 30/47.5/20/2.5.

The d3000 should do for normal use but which should I use for running in?

Because the engine has been run, you don't know where you are. I'd get some of the D1000 fuel and fire it up, warm it up and then lean/decompress/compress untill it was running as fast as it would go, then see if it would hold that setting without starting to overcompress, i.e. exhaust starting to darken. If it started to overcompress--heat up, then I would go to a break-in proceedure. If not, it's ready to fly, set maybe a hair rich on the needle. When it gets where it starts and runs without having to adjust anything, then it is broken in.

I would trust Jim T's advise on diesels, but I reached the same conclusion, from looking at both the oil and ether contents. The increased ether in the D1000 mix will make it run cooler, but I would never proclaim an engine as completely run-in until it would hold a good setting on the normal mix, D3000. After a few of those indestructable British Combat designs, try a Netzeband designed Splinter. It is a high aspect ratio design, and you will be amazed at how much better it flies. Steve

Hi Tony,

I'd use the DS1000 as it has a higher castor content and it is the recommended fuel for running in. The DS3000 will be fine for top performance. There's nothing wrong with using DS2000 for sport flying.

If you are not to good with the dizziness caused by circulating at high speed you can slow you lap speeds by using the 1000, or 2000.

George Aldrich used to run in his diesels doing lazy eights as they do not put an undue strain on the engines.

If you want to calm down the combat wing you can move the C of G forwards by packing som lead in the engine pod behind the engine.

My first combat wings were the FARTs from AMI. It was designed specifically as a trainer by Ian Peacock. I built mine using rather heavy balsa and was satisfied with their perfromance until I built a Vernon Hunt Warlord. It was educational discovering the low density balsa used in the kit. I did not think that it would survive the first unplanned landing but it has done surprisingly well. A crushed wing tip only.

It is far twitchier than the FARTs but has superior line tension in the overheads and a lot more fun to fly.

Are you going to build one from plans or a Hallam Kit?

You never know, you might get round to building a Mercury Picador or Toreador (a really lovely flyer).

Good luck with your endeavours.

For my sins I am going to build a Russian style mylar coverered PAW 1.0 CC powered combat wing from Hallam Models. Bob Meager reckons it is the most funthat you can have with your trousers on!

I'm going for Hallam kits they seem good value and I saw quite a few flying at the Nats.

Tony

As you might recall I don't drive and live in a flat in a built up area - running in motors is difficult!

What are your suggestions for a portable, lightweight test stand - I was thinking of a cheap camera tripod with a ply plate on top and a commercial engine test stand and tank mounted on that!

I could peg the stand to the ground or brace it to my flight box!

Any other suggestions?

You might think about making an individual engine mount out of heavy enough plywood or hardwood and either just holding it or using a a C-clamp or two to clamp it to a table or fence or whatever is available at your field.