Oddball engines and prototypes

[Lightbulb]

Interesting reading the Eulogy of Don.
Maryborough is where there is an model plane club flying site where they race the 6.5cc RC pylon racing planes .
Obviously a place of speed and racing in Australia.
Neil

[husaberg]

[pete376403]

"Superblend"? - Are they also called barrel rollers? - guess they were a bit of a compromise, but they did work.
Had a ride on a "Combat" many years ago - impressive amount of torque!

Yes, barrel shaped rollers. more here :http://www.accessnorton.com/what-superblend-t3722.html

[guyhockley]

Plenty of modern "complete" head/barrel examples in the two stroke scene, especially in chainsaws and the like. Not great for buckets though to get the squish clearances right! but then knowing our "bucketeers" they would no doubt, get round that one with head inserts

Manufacturers of powered harnesses for hang gliders almost universally use a kart engine called the Radne Raket, which I think was originally based on a Husqvarna engine with integral head/barrel. There is an upgrade, called the Red Head which involves slicing the top off and replacing it with a detachable head.
http://wind-drifter.com/technical/redheadinstall.php

[Frits Overmars]

Commando cranks used to flex to the extent that the main bearing rollers were running on their end edges, rather than the whole width of the roller. "Superblend" rollers were used to mitigate this - the cranks still flexed, but the bearing lived (longer)

All cranks flex. In the case of the Aprilia RSW/RSA engines, crank flexing was allowed through lightly barrel-shaped inner races; the rollers were conventional cylinders.

[WilDun]

Takes me right back to my schooldays when I found two of those Bristol engines (complete radials) in the local scrapyard and I visited them each day on the way home from school - we were not really allowed to go into such places, but I managed to sneak in most days for a while to drool over them (think I might have been about 14-15 at the time).
They were off a crashed Wellington bomber (which had piled into a cliff about 10 miles away during WW2). I was hoping to buy them and take them home, but no cash unfortunately - fortunately?
I hadn't heard of sleeve valves then, but I got as much info on the engines as I could and found out about the unique valves they had - They have intrigued me ever since!

I believe the Napier Sabre aero engine also used sleeve valves (expertise in these was gained through co-operation with Bristol) it had a 24 cylinder 'H' layout, as opposed to a radial and was used in the Typhoon ground attack aircraft). Also I believe Lycoming (Continental?) in the US designed and built a sleeve valve engine which didn't actually go into production.

[Pursang]

All cranks flex. In the case of the Aprilia RSW/RSA engines, crank flexing was allowed through lightly barrel-shaped inner races; the rollers were conventional cylinders.

Some early *onda engines had roller mains in the first models & changed to ball bearings in the subsequent ones.

[Grumph]

Some early *onda engines had roller mains in the first models & changed to ball bearings in the subsequent ones.

Probably cost related - you look at early XL250's and CB450's where they ran rollers direct on the shafts then the later versions with ball mains and soft shafts...the early versions are almost built regardless of cost. While the shafts undoubtedly flex, they're better supported and bigger dia press fits than the British engines. The first 250 Motorsport in particular is almost Manx Norton in the shaft sizing.
They don't tend to do the roller bearings from flex - age eventually sees them go through the hardening on the shafts.

[Lightbulb]

Takes me right back to my schooldays when I found two of those Bristol engines (complete radials) in the local scrapyard and I visited them each day on the way home from school - we were not really allowed to go into such places, but I managed to sneak in most days for a while to drool over them (think I might have been about 14-15 at the time).
They were off a crashed Wellington bomber (which had piled into a cliff about 10 miles away during WW2). I was hoping to buy them and take them home, but no cash unfortunately - fortunately?
I hadn't heard of sleeve valves then, but I got as much info on the engines as I could and found out about the unique valves they had - They have intrigued me ever since!

I believe the Napier Sabre aero engine also used sleeve valves (expertise in these was gained through co-operation with Bristol) it had a 24 cylinder 'H' layout, as opposed to a radial and was used in the Typhoon ground attack aircraft). Also I believe Lycoming (Continental?) in the US designed and built a sleeve valve engine which didn't actually go into production.

Nitriding of the sleeves made the sleeve valve engine a reality. Without it , they seized. The thin wall sleeves work because they are thin, and transfer any heat very quickly to the outer cylinder wall.

[husaberg]

Nitriding of the sleeves made the sleeve valve engine a reality. Without it , they seized. The thin wall sleeves work because they are thin, and transfer any heat very quickly to the outer cylinder wall.

EN10 doesn't need nitriding (on a foul stroke sleeve valve anyway)

Material designation: En 10
Diagram No.: 1311
B.S. designation: En 10
Chemical composition in weight %: 0.62% C, 0.26% Si, 0.69% Mn, 0.026% S, 0.019% P, 0.45% Ni,
0.15% Cr, 0.10% Mo
Steel group: Carbon steels
Applications: No data
Comment: McQuaid Ehn grain size: 5-6 (ASTM), actual as quenched grain size: 6 (ASTM)

[WilDun]

EN10 doesn't need nitriding (on a foul stroke sleeve valve anyway)

Husa,Tell that to Bristol and Napier!

[husaberg]

Husa,Tell that to Bristol and Napier!

It came from Rob Collet who made comparativley more HP/litre and came much later, if you take away the effect of the blower as well.

this is the sleeve drive he has although his is adjustable



when he says the issues with the piston shrouding the port this is what he means
buggar can't find the pic

[WilDun]

I like the article - I had read of another guy (I think around 1950 - can't remember the name who tried racing in IOM) but he moved to Canada and just seemingly faded away. - probably got married to an unbeliever (in bikes).
LM10 Huh? - how come Bristol didn't try it? think they may have used something like nitrided 4140, but not entirely sure.

[husaberg]

I like the article - I had read of another guy (can't remember the name who tried racing on in IOM) but he moved to Canada and just seemingly faded away. - probably got married to an unbeliever (in bikes).
LM10 Huh? - how come Bristol didn't try it? think they may have used nitrided 4140, but not entirely sure.

EN10

it may not have been arround then? but i doubt it it looks like just a plain carbon steel?
or they were looking for a fast cure as it was war time and Rolls Royce were saying their engine was shit.
From what i have read the Bristol herc was improved by a combination of tighter quality, control hand lapping the sleeves, and nitrided steel.
Maybe if the first two were correct the third wasn't needed?

[Lightbulb]

The difference was for the bike engine, it was using an Alloy LM25 outer cylinder with the EN10 sleeve liner, as I read it.
The nitriding was to prevent the steel sleeve from picking up in the steel cylinder for the aero engines.
Flettner may be able to elaborate more on this . I know they tried a lot of combinations until they arrived at the final materials.
Neil