Model Diesel Engines - Page 166 - RC Groups
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Jul 11, 2011, 07:09 AM
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earlwb's Avatar
NX-687, the engines tend to wear pretty well. But like anything used for competition, the engines eventually drop off from their peak performance. Then the engine becomes a sport or practice engine. Some brands are easier to get parts for, so you can freshen them up with a new cylinder/piston combo.

here is a nice article about the Parra engine and its performance. The Australian Control Line Journal Issue #156.
They got the engine to peak out at 26,500 rpms. But running the engine around 21,000 to 23,000 seemed to be the sweet spot. No complaints about vibration either.

The modern competition diesel engines use ABC or AAC cylinder/piston combos, and they balance the crankshaft much better too. So they don't have the problems like the old diesel engines did with steel cylinders/iron pistons and unbalanced crankshafts.
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Jul 11, 2011, 09:06 PM
Time for me to Fly...
Mr. Wiz's Avatar
OK guys, I've decided to sell off a good share of my existing collection. Why? because I want to free up some funds to collect some different engines. I want to allow my friends here that first opportunity. Take a look at my blog and if you see something you are interested in, PM me and I'll let you know how much. I'll save you some trouble. Don't ask about any of the 4-cycles, the K6 or the Drone.
Jul 12, 2011, 03:33 AM
Registered User

Thanks Mr Wiz

Good of you

Nice collection

You have to run and fly a Diesel, you have not actually been a boy unless you have fooled around with one and have had bleeding , oily , and bruised fingers , and cuts from propeller nicks adjusting compression and needle ,and ether and kero smell in your car and a model dripping black oil , Ive been out and have a blood finger , its great
Jul 12, 2011, 07:08 PM
Registered User
Mr.Wiz, nice collection of engines.
The photos are really very good and show each engine off very well.
I'd really suggest you keep these engines, especially since they all look mint/nib.
They won't be that easy to replace.
Jul 13, 2011, 08:15 AM
Registered User
earlwb's Avatar
MR Wiz that is a nice collection. I would just keep it and wait until you get more funds later.
Last edited by earlwb; Jul 13, 2011 at 08:36 AM.
Jul 13, 2011, 08:40 AM
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earlwb's Avatar
While it is not exactly vintage, it is a cool model engine, in that it can turn a prop at over 26,000 rpms which is what the current high performance diesels can do. Diesels do not have to run slow and turn big props, they can run fast and turn small props too.

This is a Parra 2.5cc AAC RC model diesel engine. I really like the little stubby micro-pipe that you can get for the engine.

Jul 13, 2011, 12:09 PM
Time for me to Fly...
Mr. Wiz's Avatar
That really is a cool little diesel you got there, Earl. I like it a lot..... 26000 rpm! Can you imagine how much air velocity at the carb!
Jul 13, 2011, 02:28 PM
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earlwb's Avatar
Here is a nice writeup article about the Parra 2.5cc diesel engine in the Australian Control Line Modellers newsletter:
They got 16,300 RPMs with a APC 8x4 prop.
And a APC 7x6 prop yeilded 17,200 rpms
The special trimmed 7x3 prop gave 26,500 rpms.
it might do better with a good 6.5x6.5 or 6.5x7 prop too.
As a modern diesel competition engine it outperforms my old Quarter Midget racing glow engines by a considerable margin.
Last edited by earlwb; Jul 13, 2011 at 02:35 PM.
Jul 13, 2011, 04:11 PM
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Gluehand's Avatar

A hard hit of nostalgia....

I finally found it.......a Webra Record of the particular '1954-59'-version...and it's 'NIB', unrun...

For your info, this is the engine that my dad brought home, I think 1958....
Not my first engine though, but my first 'real' certainly has a special place in my heart...I have so many memories with this one.....
I have to confess that just re-seeing the box again, slightly raised my heartbeat...

I know this engine isn't among the rarest ones, although strangely, I haven't been able to find one since my 'engine collecting' started...

Yeah, indeed I feel happy with this purchase....full circle...?...time to stop collecting now..?...well.....

Jul 13, 2011, 04:30 PM
Electrif(r)ied nitroman
danny.act's Avatar
Congrats with Your find Gluehand !
Nice story connected with Your Webra find.
Jul 13, 2011, 05:11 PM
Registered User
earlwb's Avatar
Congratulations GlueHand. Nice find. sometimes something can be hard to find and other days, the things are just everywhere, until you want one.
Jul 13, 2011, 05:14 PM
Registered User
Gluehand, that's a beautiful little diesel. And of course all the good old memories.
In 1959 I wanted the Cox .15 Olympic. I didn't have the $12.95.
Still wanted it 20 years later, found a nib, bought it, still have it and like it.
Jul 13, 2011, 05:20 PM
Registered User
Earlwb, have you run your Parra yet. I wouldn't go pushing it over 20K unless you have a spare rod. I got the first ones with the steel liner. I'm happy to keep the revs down with large props. Mine came with an Enya muffler and an MVVS RC carb.

newer gold head Parra
Last edited by JohnAV8R; Jul 13, 2011 at 05:24 PM. Reason: Parra link
Jul 13, 2011, 05:37 PM
Registered User
Gluehand's Avatar
Thanks guys......I can assure you this one will be will be a pleasure to give it a gentle run-in for a start, and, no C/L though ...rather something more slow, friendly and dignified....

Originally Posted by earlwb
sometimes something can be hard to find and other days, the things are just everywhere, until you want one.
Absolutely true......remember I just recently found another, used example (the one with a problematic contra piston)....suddenly they just turn up from nowhere....
Jul 13, 2011, 05:46 PM
Registered User
I love those Records.
Very nice to see one in the box after all those years, and without the radial mount chopped out so it could be bearer mounted.

I fired one of mine up a couple of days ago as if the weathers fine enough I'll take it for a fly.......the model I'm not sure about.......I've found it hard to keep on trim from session to session.

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