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Which is better OS .91 or Jett .90 and for that?

Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

Which is better OS .91 or Jett .90 and for that?

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Old 09-21-2006, 11:25 PM
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aaviles
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Default Which is better OS .91 or Jett .90 and for that?

I am a little confused as for that motor is better to use in a jet since I was looking at the specifications of the OS .91 RPM 2K to 16K
and the specification of Jett .90 are 15k wit LX muffler.


somebody can take me out of doubts
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Old 09-21-2006, 11:31 PM
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Default RE: Which is better OS .91 or Jett .90 and for that?

I'm pretty confident that the mighty Jett 90 would dust the OS .91

Now if that was an OS 91 Ducted Fan engine......well that would be interesting.... [&:]
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Old 09-22-2006, 01:03 AM
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Default RE: Which is better OS .91 or Jett .90 and for that?

well the OS is a good sport engine the Dub Jett is an excellent Performance engine.

while OS claims theirs does 16K ( but with what prop and fuel?)

Dubb Jett states what HIS engine DOES!

I have several Jetts , too many to list again, but the last one is a 50 BSE. I broke it in per instructions and then set the needle for flying (just a tad on the rich side). I did not have to touch the low speed needle it was dead on!

If you want to fly around the patch and save some $$ by the OS.

If you want to kick some serious butt by the Jett.

just my .02

Bob

SIG Kobra Jett SS.40
Magnum Jett sport .50
ACM Whiplash Jett FIRE .50
Great planes F-4 Jett 1.20
nitro planes Bobcat Jett .50 BSE

Waiting for an airframe Jett 60LX FIRE , Jett .30 BSE FIRE, Jett .76
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Old 09-22-2006, 01:07 AM
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Default RE: Which is better OS .91 or Jett .90 and for that?

from the Jett web page:

BSE .50 R/C with muffler AAC 17,000 10x6

I got 17,500 with a 10x7 APC pusher prop 15% fuel

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Old 09-22-2006, 06:55 AM
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Default RE: Which is better OS .91 or Jett .90 and for that?

Well it happened,after at least 175 flights my jett 90 had a dead stick landing,But I should have known the tank was out of fuel.Doo!No problem with the plane.Nice landing.Man I love my Jetts 90`s.
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Old 09-22-2006, 09:59 AM
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Default RE: Which is better OS .91 or Jett .90 and for that?

Lets see here, a OS 91fx, G90, sand most other 90's along with a Jett 90 all have the same thing in common, they are all the same size but they all do not have the same power. Rpm ratings mean nothing. Jett will out perform all of them.
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Old 09-22-2006, 10:11 AM
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Default RE: Which is better OS .91 or Jett .90 and for that?

The OS .91FX only turns around 12,500 RPM, and is not a very powerful
engine. The jett .90 in real life has about 50% more power than the OS.

THe OS is just a bored out .60. []

FBD.
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Old 09-22-2006, 10:35 AM
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Default RE: Which is better OS .91 or Jett .90 and for that?

Just to be fair, the OS91FX can perform pretty well, when propped correctly, and it really needs a tuned exhaust.

Configured like shown here, it runs pretty well.
http://www.rcuniverse.com/forum/fb.asp?m=4564450
and it can produce some good power.
This one here has a jett-stream muffler, a good fuel system, and an APC 12x8 on the shaft. Look for between 12,000 and 12,500 rpm on the ground, and it will unload nicely onto the pipe in the air.

Most guys over-prop the heck out of the OS. Dave nailed it - it is just a "big" .60. For most sport/speed use, a 12x7, 12x8, or 11x10 is the most you would want on it. Drag it down much below 11K rpm and it is dogmeat (without some help from a pipe or something)

The Jett 90L is pretty well documented here. Generally prefers a bit less pitch, 12x6 typically, but runs about 1500-2000 rpm higher on the ground and unloads a ton in the air.
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Old 09-22-2006, 11:04 AM
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Default RE: Which is better OS .91 or Jett .90 and for that?

....now, here's a decent OS .90....[sm=thumbup.gif]
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Old 09-22-2006, 11:09 AM
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Default RE: Which is better OS .91 or Jett .90 and for that?

The OS 91 and the Jett 90 shouldn't even be mentioned in the same sentence. THERE is NO comparison.

The reason I have my Jett 90 is because I HAD the OS 91.

I tried everything to get that OS to run. Save a little extra moola and get the Jett 90, you won't be sorry.

Gary
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Old 09-22-2006, 11:15 AM
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Default RE: Which is better OS .91 or Jett .90 and for that?

....these are good as well....if you like RPM's.
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Old 09-22-2006, 12:04 PM
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Default RE: Which is better OS .91 or Jett .90 and for that?

ORIGINAL: aaviles

I am a little confused as for that motor is better to use in a jet since I was looking at the specifications of the OS .91 RPM 2K to 16K
and the specification of Jett .90 are 15k wit LX muffler.
Those are not specifications per se, simply an operating RPM range. The numbers mean absolutely bugger all, zero, zip, nada because there is no mention of the load the engine is turning at that rpm. If you looked at a .15 with a rating of 2k to 16k, would you think it had the same power output as the .90's? Point made I think.

This is why numbers like that are listed - to obfuscate the issue for consumers who may not realize there is no standard load being applied to the motor, and who then might make a decision based on the numbers they read.

That is why Jett's ratings are, in opposition to standard practice, meaningful. They list rpm with a specific load, and that allows you to make an objective comparison if you have the same data for another engine. Or to compare between the various Jett models.

They are a top drawer motor, strong as blazes, beautifully made and robust, top notch carburetion, lessee, what else? Well, you get what you pay for is the basic truth. So if it doesn't kill you too much to plunk down the dough for one, it is highly unlikely you will be disappointed, and highly likely you will be as happy with your choice as the others who have chimed in with their support. Plus, you have the honor of NOT having a run of the mill engine at the flying field, so you ge to answer all those "what's that?" questions.
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Old 09-22-2006, 12:12 PM
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Default RE: Which is better OS .91 or Jett .90 and for that?

Is this the thread where we can sign up to be in Flyboy Dave's will? I mean, with him being SO OLD AND TREACHEROUS- sitting on a stockpile of engines, it would only make sense to make me the "trustee" of his RC estate, so I can disburse his assets amongst the Revvers, should something happen to him.... heaven forbid!

Just wondering [X(]

FBD- Are we going for pink slips this time or what? And yes I am serious...
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Old 09-22-2006, 01:26 PM
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Default RE: Which is better OS .91 or Jett .90 and for that?

The Jett .90 is my favorite of the 3 that I own (.35, .50, .90)

I've run it a few times this summer and it just runs great in my Corsair. Screams across the field and scares the children, I love it!

My O.S. .91FX powered Kyosho Geebee rarely gets flown because I've never had that motor running right.
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Old 09-22-2006, 11:10 PM
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Default RE: Which is better OS .91 or Jett .90 and for that?

Thanks to all I am already convinced[sm=biggrin.gif] Jett .90
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Old 09-23-2006, 12:50 AM
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Default RE: Which is better OS .91 or Jett .90 and for that?

Why don't you two each bring out 3-4 nice R/C items that you cannot live without but could if you had too and the winner gets choice.

Something like a nice NIB engine that has been sitting onthe shelf for 5 years waiting on a project your never going to do.
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Old 09-23-2006, 08:39 PM
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Default RE: Which is better OS .91 or Jett .90 and for that?

Just got back from a club race. My Jett 50 in a Matney Models Zoomer went in at about 160mph from about 500 ft. from total control loss. Dug out my old (4th year) Jett 35, cranked her up and won all three heats, lapping most. Darn thing just keeps getting better each year of love and care. Same for the 50 and especially true of the 90. They are all getting better with age, love each and every one of the things. A OS run the same way and hours will be lucky to make it through the first year, period!!!!!!!!!!!!!!!!!!!!!!!!! Just my opinion.
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