RE: Silver Swallow Pulldown
 

What is the purpose of raising the cylinder by that much?
Aren't you just loosing crankcase pressure when the stroke is the same?

RE: Silver Swallow Pulldown
 

Thats exactly what I said.http://www.rcuniverse.com/forum/js/f...ular_smile.gif

RE: Silver Swallow Pulldown
 

Fiery , I ran up your donor engine , its not too bad , I got sub piston induction by mistake and made about 3 pistons to get the fit and 2 goes at lapping the cyl , , It just would not seal , the plane is about 1/3 finished , The piston is very thin and the conta piston has 1mm between the combustion chamber and the tommy bar screw and its hollowed out , With this radial porting it looks like the transfer charge just goes straight out the exhaust, I might try a real steep domed piston or deflectors on the piston top ,

RE: Silver Swallow Pulldown
 

Hi!

I do recall it had a conical piston crown.

I have to say I found it most difficult to start. I believe the seal was poor.

RE: Silver Swallow Pulldown
 

It didnt come up very well after the run in its a little loose , its got a lot of taper on the cyl and too much exhast timing and also sub piston induction that I dont want , I will fly it next week in the same model as my No1 Silver Swallow and see how it goes

its out to about 1.8 cc 's with a long crank like the first one and the 11mm longer conrod made it heavier

Its got a bigger counterweight in the crank shaft

RE: Silver Swallow Pulldown
 

Radial ports do work but you may have lost most of the air-speed in the new charge, as you will really loose a lot of the crankcase pressure with the long extension beneath the cylinder.

RE: Silver Swallow Pulldown
 

I have given my Silver Swallow a flight clearance for this weekend

with a shaft timing like an OS 45 and 155 degrees of exhaust timing and an 8x6 prop it should run

I have already heated the piston to red hot and quenched it in oil 2 times , it was high tensile cast iron , I dont know what type

Its a bit loose but should start , I have to use an exhaust ring as most clubs have a muffler rule

Unless I fly down by the old steel rolling mill

The vibration is OK , its got a crank web cutaway and a 6 by 2.6 copper counterweight and a smaller piston pin than stock

I have run a 2.5 mm piston pin for a few tanks, on the ground, in a steel piston ,and it was OK but I made this one 3mm , in a cast piston

For my next cyl Im going out to 13.1 from 12.8

and in this one I have the biggest crank I can fit

I had to cut out part of the case as the rod was hitting

RE: Silver Swallow Pulldown
 

Looking inside

RE: Silver Swallow Pulldown
 

An old clubmate has a Silver Swallow in a Montgomery c/l trainer. It was a major disappointment as a diesel. so he converted it to a glow.

It was even more of a disappointment!

Here's a pic of it at the Veterans weekend at Muswellbrook a few years ago.

http://controlline.org.uk/phpBB2/fil...owglow_202.jpg

RE: Silver Swallow Pulldown
 

Thanks for the Photo Loctite,

they can be dissapointing , mine took about 45 minutes to start this morning and when it did it ran OK but not the power of my first Silver Swallow ,

its too loose and leaking and the exhaust timing is high , for a big prop


I will make another piston and move the cylinder down 1mm and remove the sub piston and recut the shaft timing to what PE says is a good sport diesel timing 130

155 is too much

,
and from what I read shaft balance is a waste of time on 1.5 diesels, that dont rev , so I can leave that off

The hard part is the gas tight fit

the rest can be rough enough, and will run

The cyl ext might come off and I will put the engine on a diet and get some weight off

RE: Silver Swallow Pulldown
 

I should have one ready by Sun

It will have a 2.5mm piston pin

and Ive hogged the bore out with the lap 0.5 mm very messy and long

and removed the cyl spacer and the new piston will drop the exh timming way down near 130

with no sub piston, induction

Im hoping to get a seal so it takes better than 45 minutes to start , that was tedious

RE: Silver Swallow Pulldown
 

Looking good for the weekend just have to make the contra piston ,it has a very steep taper and the piston is a lot taller , I think the reason for lacking something is that the transfer ports dont overlap the exh port

RE: Silver Swallow Pulldown
 

Overlap is not strictly needed and many old school model diesels ran fine without any.

It won't lack anything if the volume transferred is enough.

RE: Silver Swallow Pulldown
 

I am amused and somewhat gobsmacked that such a lowly engine as the 2.5 Silver Swallow has received so much attention! 4 pages no less!
Good grief, they are the epitome of poor engineering!
I've got 5 or 6 out in the shed that I stupidly said I'd sort for a friend.
They are unadulterated rubbish of the first order. [:@]
I won't say they are all like the ones Howard asked me to sort. The very early ones with the more rounded heads and non anodised cylinder jackets had reasonable fits. These were the ones that came in the very thick cardboard box of pastel green and white.
Even when this batch surfaced they sold here in Oz for about $30, very cheap! Even the first ones, the 2.5's had shaft problems.
The 1.5 cc engines on the other hand were good value and weren't at all bad.
The more modern anodised versions are horrors though. Poor fits from the start, but the cases have not been machined to the correct heights to ensure the correct exhaust and transfer timings. On pulling them apart I've found that the transfers on some barely open at bottom dead center so even if they feel good, there simply isn't enough transfer timing to get enough fuel into the combustion chamber to sustain running.
They'll run off a prime of course, but any attempt to get them to run from a tank won't achieve anything!
As I say, there must be some that are happy with them, I'd say they'd have to be the lucky ones ;)
Life's too short to waste time on these things, well unless you're a masochist :D

RE: Silver Swallow Pulldown
 

Yin-Yan's / Silver Swallow's are the epitome of class engineering compared to some Aurora diesels I was silly enough to buy some years ago.

Perhaps 123Cat is part of the People's Republic's top secret "Yin-Yan Down Under Development and Test Programme'? :D

RE: Silver Swallow Pulldown
 

Yes Mr Ragla , I like pain , and there is plenty of it here

its the 1.5cc , Im doing by the way


the ones Fiery sent me

With a new crank ,rod, and piston and contra this one might run , its got 140 exh timing and 25 degree cone on the piston top , stock is 21and no sub piston induction the fit is loose half way up compression and then its good the rest , it burps in the garage so I think its a goer

Its got a tiny 2.5 mm piston pin that might break , but Im hoping ,

Im running it tomorrow<br type="_moz" />

RE: Silver Swallow Pulldown
 

Chinese Power


The Silver Swallow Emblem

RE: Silver Swallow Pulldown
 

I always preferred the 1.5 to the 2.5's
I must like pain too, with 6 or 7 of the damn things in the shed![:'(]

RE: Silver Swallow Pulldown
 

Sir Ragla


They look like they are modeled on the Webra record , they seem pretty powerful when their right , my No1 Silver Swallow 1.75cc , ( its a big block ) pulls my 14Oz plane straight up out of my hand mildly ,

so its good

Have you had any luck with your Silver Swallows in flight ??????

Ive had good luck with a Uniflow with a little exhaust pressure, from an exhaust ring and 1.5 % Amsoil Cetane, and an 8x6 , I dont rev it , I want it to torque down

RE: Silver Swallow Pulldown
 

Hope the test run brings you joy.

Make sure you post your findings.

I must be mad ... placed a bid on these things on eejit-bay.

RE: Silver Swallow Pulldown
 

Amazing , It was quite tight over the top and no seal above the exh for about 3mm but it runs OK and with 7 flights its still tight , It had to be heated to start , no cold start
Tunes well doesnt sag or get hot , and this one start at full comp I dont have to back it off like my first one

RE: Silver Swallow Pulldown
 

Well done, I love it when persistance is rewarded. My clapped out Yin-Yan lives!

RE: Silver Swallow Pulldown
 

I will put up a Photo, of your motor,Fiery , Its in a 36 , inch span 13.4 Oz AUW Flitestreak

The whole wing on this plane is 2.3 Oz painted, and finished , its light

RE: Silver Swallow Pulldown
 

Amazing,,, ?? he was also the Commander of the British forces in North Africa

RE: Silver Swallow Pulldown
 

Who will build a Rommel Trainer? :D

A favourite of the Afrika Korps ;)