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Why are there so few rear exhaust engines?

Old 08-25-2009, 04:57 PM
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Bigshark
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Default Why are there so few rear exhaust engines?

Is it just me or is a rear exhaust engine just plain sexier than anything with a side exhaust?
Old 08-25-2009, 05:05 PM
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Default RE: Why are there so few rear exhaust engines?

We can name a few:

TTR9196 - Thunder Tiger Pro 1.20 RE
PN1137 - Fuel Pump Connector for TTR9196
9263 - Fuel Pump Assembly for TTR9196
9712 - Tuned Pipe for TTR9196
9767 - Header for TTR9196

If you order all five pieces from www.infinitehobbies.com or from www.thundertiger4u.com, you're looking at about $350 with free shipping for the whole package.
Old 08-25-2009, 05:18 PM
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summerwind
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Default RE: Why are there so few rear exhaust engines?


ORIGINAL: Bigshark

Is it just me or is a rear exhaust engine just plain sexier than anything with a side exhaust?
absolutely they are SEXIER........and in the right planes, the rear exhaust with tuned pipes just plain scream............
one of my favorites was the Rossi .61.

one of the best available at this time in the 60 size is from Jett Engineering and well worth the money...............

http://www.jettengineering.com/

with so many people not building anymore and just going with ARF's, the FIRE engines are just not practical as they don't fit much that is available.
Old 08-25-2009, 06:32 PM
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Default RE: Why are there so few rear exhaust engines?

On most airframes it would be a pain if the exhaust was rear. So I guess we sacrifice performance for ease of installation.

David
Old 08-26-2009, 06:06 AM
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estradajae
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Default RE: Why are there so few rear exhaust engines?

Does it have something to do also since the 2 stroke FIRE engines were used mainly in Pattern ships and now most of they have gone to 4 stroke engines??
Old 08-26-2009, 07:07 AM
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Default RE: Why are there so few rear exhaust engines?


ORIGINAL: estradajae

Does it have something to do also since the 2 stroke FIRE engines were used mainly in Pattern ships and now most of they have gone to 4 stroke engines??
Jorge,


In the 2.00 x 2.00 m F3A field, about half have already gone to electric power, with Hacker C50 motors and the like...

So, the OS1.40RX and Mintor 1.40/1.70 rear-exhaust two-stroke engines, are two generations back; not just one...


And, BTW, MVVS engines, from 2.5 cc to 15 cc (.15-.91), can be rotated to change their configuration to RE... It takes minutes.

Old 08-26-2009, 07:16 AM
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Default RE: Why are there so few rear exhaust engines?

Most rear exhaust are pipe timed and so they maximize the benefit of the tuned pipe/ exhaust system. So not only do they look sexy, they make more power. There are very few pipe timed side exhaust engines. Some of the after market assemblies are available with pipe timing.

I have always felt that the change in displacement in pattern started the demise of the 2-stroke .60 killing the big need for rear exhaust use/ applications. There were a few 1.20 2 strokes offered in RE. Mintor, OS Thunder Tiger(1.20) and Webra still offer RE engines in the big 2 cycle market, but the 4 stroke has left so little demand that they are almost gone. I can imagine that a engine manufacturer looks at the demand for RE engines and can't get excited about investing time and money for such a small market. There have been several attempts with RE that just never took off ( K&B even designed a 1.50and the Webra based Bully). Some small gas offerings have entered the picture. Consider all the plus the advent of electric, which will shrink the market even more (IMO). I'm am afraid it looks bleak for more RE glow offerings in the future. I would love to be wrong on this one!

turbo
Old 08-26-2009, 07:16 AM
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estradajae
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Default RE: Why are there so few rear exhaust engines?

I hope it´s not going to be hard to keep our hobby (with glow eingines) in the near future =(
Old 08-26-2009, 11:08 AM
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Default RE: Why are there so few rear exhaust engines?

[link=http://www.enya-engine.com/store/index.php?main_page=product_info&products_id=460&zenid=291e1a046b9338b1439fc1cbf581b897]Enya[/link] have just released their 32 CXL TN (for RC) and CXLS (for CL) rear exhaust engine and I suspect it's just the first in a new range of RE engines. I have quite a number of RE engines (hey, I like them ) ranging from OS 40-61VF's, Irvine 40 and 61, Stalker 61, Stass's 42 and Taipan 15. Rear exhaust doesn't necessarily mean high timing though, the 40-46 VF's are very mildly timed, the VF61 and Irvine 61 have normal (SE/muffled) RC timings.

Most current RE engines though are designed for CL stunt and either aren't easily available (you can't just go to your LHS and get one) or are quite expensive. They can be used either with a pipe or muffled. Jett sells a muffler hidden inside the header pipe for their RE engines. Regardless of the hype, I have my sincere doubts that electrics will take over any time soon.
Old 08-26-2009, 11:25 AM
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Default RE: Why are there so few rear exhaust engines?


ORIGINAL: downunder

[link=http://www.enya-engine.com/store/index.php?main_page=product_info&products_id=460&zenid=291e1a046b9338b1439fc1cbf581b897]Enya[/link] have just released their 32 CXL TN (for RC) and CXLS (for CL) rear exhaust engine and I suspect it's just the first in a new range of RE engines. I have quite a number of RE engines (hey, I like them ) ranging from OS 40-61VF's, Irvine 40 and 61, Stalker 61, Stass's 42 and Taipan 15. Rear exhaust doesn't necessarily mean high timing though, the 40-46 VF's are very mildly timed, the VF61 and Irvine 61 have normal (SE/muffled) RC timings.

Most current RE engines though are designed for CL stunt and either aren't easily available (you can't just go to your LHS and get one) or are quite expensive. They can be used either with a pipe or muffled. Jett sells a muffler hidden inside the header pipe for their RE engines. Regardless of the hype, I have my sincere doubts that electrics will take over any time soon.

Last year I bought a Rossi .61 AXE rear exhaust engine from rossieusa on "The Bay". The price was high at $299.99, but whatcha gonna do? If you want to play, you're gonna pay. I have a Bridi XLT kit which was just begging for a RE engine. Now it has one. The engine is unran, but beautiful. We're talking BPA here, or a great sport flyer. I couldn't get my hands on Rossi engines back when I was flying pattern (trying anyway). My timing was off. When I had the money for a Rossi, they were always out of stock. Now I have six or seven Rossi engines. It's funny how things work out. I love four-strokes, but they don't interest me for classic pattern. It's true that the electrics are taking over, but not for me. I like electric powered models for sport flying, but no way in a classic pattern model. I would even forbid four-strokes. Two-strokes only in classic pattern. I just woke up. Where's my coffee?


Ed Cregger
Old 08-26-2009, 01:24 PM
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Default RE: Why are there so few rear exhaust engines?

I knew about Rossi and Jett but had no idea TT, MVVS, and Enya had rear exhaust engines. I'm glad to know there are more than just a couple out there.

On another note, It can't be that hard to mount a rear exhaust inverted on quite a few arfs or kits. Someday I'm just going to have to build that Bridi Kit that ducts the exhaust directly through the canopy.

I've done electric and I'm NEVER going back except for my electric sailplanes. If it doesn't scream, I'm not interested......
Old 08-26-2009, 02:26 PM
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Default RE: Why are there so few rear exhaust engines?

I think they mentioned many of the reasons. We just do not have a lot of plane designs nowadays that use a rear exhaust engine.
I used to fly pattern when .60 engines were it, and the pattern planes were designed to allow for a rear exhaust engine and tuned pipe to fit into the fuse nicely. But since then everyone started going giant scale and 3D instead so the market for rear exhaust engines has become very limited.

I use Fox engines and the current Eagle 60's can be easily converted to rear exhaust by rotating the outer cylinder casting and realigning the piston ring ends to not catch on the ports.

Now Nitroplanes.com has a ARF pattern plane designed for the YS 110 that would work good with a .60 rear exhaust and tuned pipe in it.
That seems about it for modern planes that use rear exhaust.
So then you get into the pylon racers and they still have some rear exhaust engine plane designs. A rear exhaust engine design in a pylon racer helps as it is a lot more streamlined cutting down on aerodynamic drag of course.

Old 08-26-2009, 04:38 PM
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Default RE: Why are there so few rear exhaust engines?

FOX had a decent idea on the.74 engine making the head turnable to a rear exaust, i dont know why nobody else picked up on it.
if your mounting an engine upside down , its really better to have the exaust in back of the engine, especially if the cowl is
cramped.
Old 08-26-2009, 06:27 PM
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Default RE: Why are there so few rear exhaust engines?

OPS is now selling a .90 and a 1.20 rear exhaust engines. with both turning over 24,000 rpms they aren't for beginners. here is a photo of the marine version (shipped incorrectly) i received recently. the air version looks even better. i'll try to find a photo.

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Old 08-26-2009, 10:44 PM
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Default RE: Why are there so few rear exhaust engines?

Gee, even after 35 years or so, this rear exhaust Taipan 2.5cc still makes me swoon. Yep, sex sells! [8D]
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Old 08-27-2009, 07:59 AM
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Default RE: Why are there so few rear exhaust engines?

MVVS 20 with the cylinder rotated to rear exhaust set up. I just loved being the fastest kid on the block in a combat bout!
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Old 08-27-2009, 09:28 AM
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Default RE: Why are there so few rear exhaust engines?


ORIGINAL: dhal22

OPS is now selling a .90 and a 1.20 rear exhaust engines. with both turning over 24,000 rpms they aren't for beginners. here is a photo of the marine version (shipped incorrectly) i received recently. the air version looks even better. i'll try to find a photo.


That picture looks like something that belongs in a nuclear reactor. Nice. Who the heck is OPS?
Old 08-27-2009, 10:12 AM
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Default RE: Why are there so few rear exhaust engines?


ORIGINAL: Bigshark

That picture looks like something that belongs in a nuclear reactor. Nice. Who the heck is OPS?
Here is an old review of an OPS engine: http://findarticles.com/p/articles/m...6/ai_n8790779/
Old 08-27-2009, 10:43 AM
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Default RE: Why are there so few rear exhaust engines?

ORIGINAL: Bone
Gee, even after 35 years or so, this rear exhaust Taipan 2.5cc still makes me swoon. Yep, sex sells! [8D]
And guess what? That's one of the fairly rare Mk1 Taipans and I only found out about them around a week ago which made me go look at one of mine. Yep, mine's a Mk1 as well and it's the one I've thrashed around in a combat plane before letting my son use it to (over)power a glider. The difference is a bit hard to spot but the first ones used a narrow rear bearing so the crankcase casting is slightly different to the later metal backplate engines (might as well call them Mk2's). I've also got one of the last in the line with the plastic backplate (I think the crankshaft is different too) but that one's new. Apparently they were good for over .5HP at around 22,000 using 40% nitro.
Old 08-27-2009, 11:18 AM
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Default RE: Why are there so few rear exhaust engines?


ORIGINAL: blw


ORIGINAL: Bigshark

That picture looks like something that belongs in a nuclear reactor. Nice. Who the heck is OPS?
Here is an old review of an OPS engine: http://findarticles.com/p/articles/m...6/ai_n8790779/

Thanks,

..learn something new everyday.....
Old 08-27-2009, 10:05 PM
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Default RE: Why are there so few rear exhaust engines?


ORIGINAL: downunder

ORIGINAL: Bone
Gee, even after 35 years or so, this rear exhaust Taipan 2.5cc still makes me swoon. Yep, sex sells! [8D]
And guess what? That's one of the fairly rare Mk1 Taipans and I only found out about them around a week ago which made me go look at one of mine. Yep, mine's a Mk1 as well and it's the one I've thrashed around in a combat plane before letting my son use it to (over)power a glider. The difference is a bit hard to spot but the first ones used a narrow rear bearing so the crankcase casting is slightly different to the later metal backplate engines (might as well call them Mk2's). I've also got one of the last in the line with the plastic backplate (I think the crankshaft is different too) but that one's new. Apparently they were good for over .5HP at around 22,000 using 40% nitro.
Brian, thanks for that very interesting snippet of information.

I've been blessed with good fortune to come across 6 of those Taipans - 2 metal backplate & 4 plastic backplate versions. Will suss out the other metal backplate one to determine whether it's a Mark I or II Sadly, I only have 4 of those damn sexy mufflers

I do understand the reasons why they used 40% nitro back in the '70. But now for me, I'm happy to feed it 10% nitro, lots of Castrol M of course, a 7x4 prop & listen to it hum along @ 16,600 RPM. What a glorious sight & sound it is !

By the way, I'm building a hand launched model - no undercarriage, tapered wing, roughly based upon a "Honker" design from the '70's - should be just the thing for the rear exhaust Taipan [8D]
Old 09-03-2009, 11:00 AM
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Default RE: Why are there so few rear exhaust engines?


ORIGINAL: Bigshark

ORIGINAL: dhal22

OPS is now selling a .90 and a 1.20 rear exhaust engines. with both turning over 24,000 rpms they aren't for beginners. here is a photo of the marine version (shipped incorrectly) i received recently. the air version looks even better. i'll try to find a photo.
That picture looks like something that belongs in a nuclear reactor. Nice. Who the heck is OPS?
Here you'll find a lot of info:
[link=http://www.rcgroups.com/forums/showthread.php?t=970617]The OPS engine thread[/link]

We're talking about true ABC constructions, high-timed to set FAI speed records for example...




Another source for high-performance rear exhaust ABC engines is Novarossi:

[link=http://www.rcgroups.com/forums/showthread.php?t=1073318]The NOVAROSSI / REX aero engines thread[/link]

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