Parra 2.5
03-04-2015, 01:09 PM
#1
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Parra 2.5
Here is the third run of the engine - starts easily and a real screamer.
Annette
https://m.youtube.com/watch?v=qqmwe1uLAoU
Annette
https://m.youtube.com/watch?v=qqmwe1uLAoU
Last edited by telmore; 03-06-2015 at 01:06 PM.
03-07-2015, 07:35 AM
#3
I have one of the Parra AAC diesel RC engines. They are great runners. Parra checks each engine out carefully before selling them to ensure the quality is up to their standards. They offer the engines as a steel sleeve lapped piston, ABC or AAC and glow as well.
For RC usage it might be tricky as the engine cools off fairly fast at low speed, thus it tends to be sluggish coming back up to full throttle as it has to heat up again.
I like the cute little mini-pipe that I got with the engine. It does offer a some performance improvement over just running no muffler too.
Since the engines were primarily intended for control line combat, the threaded crankshaft end is short and that can be a problem if you want to use a spinner on the engine.
For RC usage it might be tricky as the engine cools off fairly fast at low speed, thus it tends to be sluggish coming back up to full throttle as it has to heat up again.
I like the cute little mini-pipe that I got with the engine. It does offer a some performance improvement over just running no muffler too.
Since the engines were primarily intended for control line combat, the threaded crankshaft end is short and that can be a problem if you want to use a spinner on the engine.
03-07-2015, 07:43 AM
#4
Now I have a video I posted on YouTube that shows my engine running with a 8x4 Master Airscrew propeller. I was using Davis Diesel Development diesel fuel in it.
I was able to get a little over 16,000 RPMs with the engine and that propeller. But since the engine is new I didn't want to push it too hard. Many glow 2.5cc engines do not do that well with a 8x4 prop either.
https://www.youtube.com/watch?v=tl4OF2WOIak
I was able to get a little over 16,000 RPMs with the engine and that propeller. But since the engine is new I didn't want to push it too hard. Many glow 2.5cc engines do not do that well with a 8x4 prop either.
https://www.youtube.com/watch?v=tl4OF2WOIak
Last edited by earlwb; 03-07-2015 at 07:46 AM. Reason: typo correction
03-14-2015, 02:26 PM
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Now I have a video I posted on YouTube that shows my engine running with a 8x4 Master Airscrew propeller. I was using Davis Diesel Development diesel fuel in it.
I was able to get a little over 16,000 RPMs with the engine and that propeller. But since the engine is new I didn't want to push it too hard. Many glow 2.5cc engines do not do that well with a 8x4 prop either.
I was able to get a little over 16,000 RPMs with the engine and that propeller. But since the engine is new I didn't want to push it too hard. Many glow 2.5cc engines do not do that well with a 8x4 prop either.
Boo
03-16-2015, 03:06 PM
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My Cox Conquest .15 spins an 8x4 at 18k on the ground, 25% nitro.
I have a Parra that has a Nelson type plug, which is claimed to be the best, but is not my choice.
I have a Parra that has a Nelson type plug, which is claimed to be the best, but is not my choice.
03-16-2015, 03:47 PM
#8
My Feedback: (1)
Some of the early Parra's in the club suffered from very "wet nosed" front bearings. Thankfully this seems to have been fixed in the latest versions.
Alberto Parra actually sells a non-leaking replacement crankcase for worse case ( :-) ) engines.
The same problem may occur with a minority of the Fora Juniors diesels. Some of these leak quite badly.
They also go very well as a glow on lots of nitro.
Last edited by qazimoto; 03-16-2015 at 03:59 PM.
03-18-2015, 07:13 AM
#9
I would expect that the nitromethane in the glow fuel would allow the glow engine to outperform a diesel engine that doesn't use it.
But those Cox Conquest .15 engines are still pretty awesome today though. You have to go with some of the more exotic glow engines to outperform it.
I didn't notice if my engine leaked too much out of the front bearing. But yes I was thinking that the AAC cylinder setup might not be as good as a ABC cylinder setup. But I tend to prefer the messier engines that do ooze oil out of the front end. It lets me know it is getting oil and being flushed out regularly like that. The bearings don't have covers on them to seal them up. But I know that nowadays many people like clean engines that have little to no oil residue coming out of them.
But those Cox Conquest .15 engines are still pretty awesome today though. You have to go with some of the more exotic glow engines to outperform it.
I didn't notice if my engine leaked too much out of the front bearing. But yes I was thinking that the AAC cylinder setup might not be as good as a ABC cylinder setup. But I tend to prefer the messier engines that do ooze oil out of the front end. It lets me know it is getting oil and being flushed out regularly like that. The bearings don't have covers on them to seal them up. But I know that nowadays many people like clean engines that have little to no oil residue coming out of them.
03-20-2015, 01:19 AM
#10
My Feedback: (1)
I would expect that the nitromethane in the glow fuel would allow the glow engine to outperform a diesel engine that doesn't use it.
But those Cox Conquest .15 engines are still pretty awesome today though. You have to go with some of the more exotic glow engines to outperform it.
I didn't notice if my engine leaked too much out of the front bearing. But yes I was thinking that the AAC cylinder setup might not be as good as a ABC cylinder setup. But I tend to prefer the messier engines that do ooze oil out of the front end. It lets me know it is getting oil and being flushed out regularly like that. The bearings don't have covers on them to seal them up. But I know that nowadays many people like clean engines that have little to no oil residue coming out of them.
But those Cox Conquest .15 engines are still pretty awesome today though. You have to go with some of the more exotic glow engines to outperform it.
I didn't notice if my engine leaked too much out of the front bearing. But yes I was thinking that the AAC cylinder setup might not be as good as a ABC cylinder setup. But I tend to prefer the messier engines that do ooze oil out of the front end. It lets me know it is getting oil and being flushed out regularly like that. The bearings don't have covers on them to seal them up. But I know that nowadays many people like clean engines that have little to no oil residue coming out of them.
03-31-2015, 07:25 PM
#11
I don't know if I can agree with that completely. In the past I used and ran a lot of engines that were quite messy and oozed a lot of oil out of the front of the engines. They started and ran just fine like that. I think it depends on the design a lot. The old plain bearing bushed crankshaft engines were very messy in that respect. The older open front bearing engines were also quite messy too. Now then a older engine that has been run a lot and has a lot of time on it may start to have problems with excessive wear. Thus they would behave like you stated and become harder to start like that.
