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Jett engine, yes : which one ?

Old 12-16-2004, 06:09 PM
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Strykaas
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Default Jett engine, yes : which one ?

Hi,

I plan buying a Jett .50 engine.

There are several types :
- Sport
- FIRE
- BSE

What are the real differences ?
Are the price differences really justified ?
Old 12-16-2004, 06:16 PM
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daven
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Default RE: Jett engine, yes : which one ?

I like the standard Sport Jett .50 myself.

the Fire is (Front Intake, Rear Exhaust) and really set up for a tuned pipe.

The BSE is a Bar Stock Engine, very nice looking, but minimal performance gain over the sport jett (don't hammer me too bad for that Bob, and correct me if I'm wrong).

Dave
Old 12-17-2004, 12:10 AM
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Cyclic Hardover
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Default RE: Jett engine, yes : which one ?

Yeh, what he said.

I have the .50 and 90 sports.

ORIGINAL: daven

I like the standard Sport Jett .50 myself.

the Fire is (Front Intake, Rear Exhaust) and really set up for a tuned pipe.

The BSE is a Bar Stock Engine, very nice looking, but minimal performance gain over the sport jett (don't hammer me too bad for that Bob, and correct me if I'm wrong).

Dave
Old 12-17-2004, 05:02 AM
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Strykaas
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Default RE: Jett engine, yes : which one ?

That's good advice ! Thank u guys [sm=thumbup.gif] !
Old 12-17-2004, 10:01 AM
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Default RE: Jett engine, yes : which one ?

ORIGINAL: daven

I like the standard Sport Jett .50 myself.

the Fire is (Front Intake, Rear Exhaust) and really set up for a tuned pipe.

The BSE is a Bar Stock Engine, very nice looking, but minimal performance gain over the sport jett (don't hammer me too bad for that Bob, and correct me if I'm wrong).

Dave

Yep, thats about right Internally, the engines are about the same.

The bar stock engines do have a very slight performance improvement... but most people do not notice it.

The BSE engines are just real works of art. Cost a little more to produce, and the resulting engine price is about $50 more.

The FIRE engines can be more powerful, in that they are more custom tuned for the application when the pipe is setup.

What is your application Strykaas ?? That can help with selection.

Also...... take a moment, [link=http://www.jettengineering.com/hanger/hanger.html]go here [/link] ... sometimes a few treasures to be had

Bob
Old 12-18-2004, 05:11 AM
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Strykaas
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Default RE: Jett engine, yes : which one ?

Hello Bob,

Actually I plan using a Jett .50 in my Shrike .40 and GP Patriot.
I still don't know if I can choose a FIRE setup fore my patriot .
Application is speed [sm=biggrin.gif].
Any more suggestion ?
thx
Old 12-18-2004, 08:16 AM
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der_steuermann
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Default RE: Jett engine, yes : which one ?

Original Strykaas: ... Application is speed .
Hi Strykaas,

your motto is "Faster !!!!!!!", isn't it?

So if you are in need of "TRUE speed" instead of what could be called "sport speed" associated to Shrikes, Patriots, DD and Whips you may consider to build a "true extreme" speed plane in combination with the FIRE engine configuration. Mr. combatpigg currently builds such a true speed plane designed for maximum speeds above 230 mph depending on the engine/pipe setup.

His thread: HEY! LET'S BUILD A SPEED PLANE!!! can be found here:

http://www.rcuniverse.com/forum/HEY%...2303195/tm.htm

These "zero drag" planes are in fact quite simple constructions and easy to fly - they behave very neutrally. A confirmation to the superior aerodynamics incorporated here [8D]

Any more suggestion ?
You also might want to join the coming German Speed Cup to be held in 2006 (maybe already in 05). The more participants from abroad (also overseas) the better

http://www.rcuniverse.com/forum/Pics...2257303/tm.htm

Old 12-18-2004, 01:54 PM
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Mike Connor
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Default RE: Jett engine, yes : which one ?

ORIGINAL: Strykaas

Any more suggestion ?
thx
If you get the SJ rather then the FIRE you might want to consider getting the SS tuned muffler rather then the standard one. It is a little shorter and turns up a bit more rpm. Mine turned 18,000+ rpm with a APC 9x8 and even faster with the 8.75" pylon props. There is the even shorter black Q-500 muffler that will really turn up the pylon props but may not work too well with sport props.

There are a couple of short videos of my Shrike with a Jett 50 on my site.
Old 12-18-2004, 03:25 PM
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Strykaas
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Default RE: Jett engine, yes : which one ?

Thank you der Steuerman.

Actually, I guess I don't have the skills yet to get my hands on such fast aircraft. I'm still learning, and I don't want to go too fast .
However, your advice is interesting, especially the speed event in Germany. May perhaps pop out there, but not as a competitor maybe, I would be beat to death [sm=drowning.gif] ... Do you think a Jett .50 DD would be ridiculous ? Too much induced drag ?

Mike,

Thanks for your contribution, that was exactly the kind of information I was looking for ! Watched your videos and saw your daughter (or wife ?) breathing fresh methanol exhaust gases [:'(] ! Like the smell of castor oil in the evening, after a nice flying day [sm=RAINFRO.gif] !!! If I got it right, the supersport option is merely a shortened muffler ? Why isn't it stock ? I mean this option is a "must have" if it allows even a small RPM gain... What is the drawback ? A more touchy engine ?
Old 12-18-2004, 06:52 PM
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Mike Connor
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Default RE: Jett engine, yes : which one ?

ORIGINAL: Strykaas

Thank you der Steuerman.

Do you think a Jett .50 DD would be ridiculous ? Too much induced drag ?

Mike,

If I got it right, the supersport option is merely a shortened muffler ? Why isn't it stock ? I mean this option is a "must have" if it allows even a small RPM gain... What is the drawback ? A more touchy engine ?
I think the SS muffler should be stock as it seems to work well with a 10x6 thru 8.75 and 8.8 pylon props. At some point a larger prop/load would take the rpm out of the optimum SS rpm range and the standard muffler would be better. The engine is not any more touchy with the SS muffler. With the engine as far back as possible on the Shrike for CG reasons the standard muffler touched the wing but the SS was just right. Maybe Bob will chime in with his expert advise.

Did you not watch the DD/Jett 50 videos? I have never flown an airplane that was more fun or had more WOW factor. AT 2 lbs 12 oz with that kind of power it was like it launches out of a sling shot.
Old 12-19-2004, 01:14 AM
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Default RE: Jett engine, yes : which one ?

Noone really recommends the SJ40 anymore.. I had one these engines and absolutely loved it.. Would run a 8.5 x 7.5 on it, and always get over 19 grand on the ground.. Even got lucky and turned a 1:15 with it racing it against Nelsons one weekend in Rockford..

All them Jett engines have impressed me.. Whatever you buy from Dubb will be a great find... Goodluck..
Old 12-19-2004, 05:42 AM
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Strykaas
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Default RE: Jett engine, yes : which one ?

Did you not watch the DD/Jett 50 videos? I have never flown an airplane that was more fun or had more WOW factor. AT 2 lbs 12 oz with that kind of power it was like it launches out of a sling shot.
Yes I did [sm=eek.gif]. "Unlimited vertical is redefined", yes indeed [X(][X(][X(] !!!! You were on an APC 9x8 too, right ? Or pylon prop ?

Strega,

Yes, still have to see bad comments about these engines... I still hesitate between a SJ and the FIRE .

thx
Old 12-19-2004, 02:17 PM
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Mike Connor
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Default RE: Jett engine, yes : which one ?

ORIGINAL: Strykaas

You were on an APC 9x8 too, right ? Or pylon prop ?
I believe I was using a 9x8 in most of my videos. I tried many props but the APC 9x8 was my overall favorite on the DD and Shrike. The pylon props may have been a bit faster but had less thrust for launch.
Old 12-19-2004, 08:52 PM
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Default RE: Jett engine, yes : which one ?

ORIGINAL: Strykaas

If I got it right, the supersport option is merely a shortened muffler ? Why isn't it stock ? I mean this option is a "must have" if it allows even a small RPM gain... What is the drawback ? A more touchy engine ?
The Jett mufflers are not just empty cans like other common mufflers, they are in fact "mini pipes"... They are part of the excellent Jett reputation when it comes to power. They funtion as a tuned pipe and are therefor tuned for a specific rpm band.
The stock .50 Jettstream muffler starts to kick in at about 16500 rpm, so you must prop the engine to run at 16500+ rpm.
With the shorter SS muffler the ideal rpm band shifts to 18000+ I believe.
The Quickie 500 muffler requires you to run the engine at at least 19000 rpm.
Propping the engine below the rpm band of the tuned muffler may result in slight overheating symptoms and more difficult needling behaviour.

So the SS muffler does not increase rpm on a big prop, but it allows you to use high rpm small props more effectively.
It all depends on what you intend to do with the engine, but remember that an SS equipped engine is not an ideal setup for pulling those bigger props. For that you will want the stock Jettstream muffler.

For a Diamond Dust I recommend you get a FIRE engine... it makes for a much cleaner setup.
With the experience I gained from my Webra .32 equipped Dust, I say that the Dust probably will work very well on APC 8.75" pylon props.

A rear exhaust on a Patriot will probably require quite a rebuild to get that tuned pipe mounted. A side exhaust SJ 50 will probably be the easiest "go fast" package you can buy.

On a Shrike, like on a DD, it is easier to incorporate a rear exhaust engine.
Old 12-20-2004, 02:24 AM
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Default RE: Jett engine, yes : which one ?

I was going to run my new Jett .50 on the test stand today, but it looks like I received the wrong muffler [:@]: the screws are 6-32 and fit just right through the exhaust "shim", but the muffler is tapped for 4-40.
I gues I need to call Dub tomorrow ???
Old 12-20-2004, 08:54 AM
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bob27s
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Default RE: Jett engine, yes : which one ?

Thanks for providing that information folks.

Island...... send Dub and Email....... he may have gotten an order mixed up and send the 4-40 muffler by mistake.
[email protected]
The muffler is the same... some are built with 4-40 holes for use on TT, OS and Webra engines.

The info provided above is correct. The SS muffler is tuned for a bit higher RPM band, typically 17-19K rpm, where as the standard Jett-stream muffler kicks in somewhere around 15K, and runs best between 16-18K rpm. Jett SJ46 and SJ50 engines respond best with this turning ground rpm over 16K rpm. As noted, prop selection is important with the Jett mufflers. The SS muffler works best on quick airframes where the engine can easily unload, and where using smaller 8.5-9" diameter props is practicle.

Dub sells a "Sport Q-500" combination that is a SJ-50 with the q-500 muffler. Works well for most of these speed ships.

Strykaas, your engine selection depends a great deal on the aircraft you select. If you choose an aircraft suitable for the FIRE configuration, providing that information when ordering the engine is very useful. Dub can provide a tuned pipe system (pre-tuned) and test run the entire setup before you receive it. He will also tell you the RPM the pipe is tuned for, and recommend a few props that will work best in that RPM band.

You can use the FIRE configuration on a Patriot if you wish. Run the pipe down the fuselage side. I noted a few nice photos of a King Kobra with a YS RE on here.... same sort of layout. I would not suggest the high timed engine noted above...you need more prop on the patriot. But in general, the performance gain you get with the FIRE over a standard side exhaust engine is minimal, and I would recommend the SJ-50 for the Patriot 40.

For true speed with whiplash/DD and other RE configurations, Dub can provide a high-timed FIRE 50 that will simply amaze you. Its a bit less user friendly (takes a run or two to learn the needle proceedures). But thats just a bit of practice.

Of note, Dub generally does not generally sell the SJ-40 any longer. The .40 engines are only available in racing versions since they are required that size by rule. Main reason, is the SJ-46 cost the same as (less than?) the 40, it turns a 10x6 better, and is better suited for sport flying applications. That said, and of the Q-500 .40 engines can be ordered with the sport 2-needle carb if desired.

Bob

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