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

What engine do I need for maximum speed?

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Old 09-24-2008, 01:37 PM
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krkenned
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Default What engine do I need for maximum speed?

I just recently bought a Weston Magnum (.46 size airframe) and am looking for different suggestions on what engine to put in it. I am interested in the fastest speed possible but don't want any engine that is a hassle to tune or maintain. The only engines that I have been able to find are the Jett and Nelson engines. Are there any other comparable speed engines available?
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Old 09-24-2008, 02:02 PM
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evan-RCU
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Default RE: What engine do I need for maximum speed?

The Nelsons typically are pure breed racing engines and most do not have a true carb and are more difficult to tune. The Jetts are almost as fast and can be bought with a true carb making them easier to tune. I have a Weston .50 on mine and it is what was sold with the Magnum as a combo, with a tuned pipe. The Weston .50 is a reworked Webra Speed .50 and a wonderful motor.
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Old 09-24-2008, 02:10 PM
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Default RE: What engine do I need for maximum speed?

The Jett engines are easy to use ... very user friendly ... plus you get good performance No real tuning or set up... just break it in as per instructions, bolt it in the plane, set the mixture about 800 rpm down off of peak rpm ...... and you are good to go.

If you want an econo-speed setup ......

TT46 pro (my preference for econo-speed)
Webra 55
Evolution 46, 50

Bolt on a jett-stream muffler to any of those, use a 9x7 prop - and the Magnum will keep you happy all day

OS 46AX works too ... just us a 9x8 or 9x9 (it is set up to run at lower rpm).
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Old 09-24-2008, 03:48 PM
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SpeedBoy
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Default RE: What engine do I need for maximum speed?

Besides the jett , what about a Rossi .53 .

If you can wait until middle of octuber they will be available on SG MODEL ENGINES and they will come with the large Rossi 10mm
venturi carburetor for max power .

As I got a good results with the Italian ( even with the short carb. ) I dare to recommend you this one just like another option .


Regards .
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Old 09-24-2008, 03:50 PM
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krkenned
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Default RE: What engine do I need for maximum speed?

Bob,

I have been looking into the Jett 60LX. I would like to get the FIRE engine however, I don't think it will work with the Magnum fuse. Are there any differences in performance in the FIRE and normal side exhaust engines?
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Old 09-24-2008, 04:59 PM
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Default RE: What engine do I need for maximum speed?

I had the jett 60 Lx on the magnum. No need for the fire.
It is a little yellow rocket!!!!!!!!!!!!!!!!!!!!!
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Old 09-24-2008, 05:26 PM
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Default RE: What engine do I need for maximum speed?

you could try the engine the plane was designed for a weston 50 v1 and genesis tuned pipe.

Mind you i would love to try a rossi and a jett oh and nelson bla bla in it too!!!!
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Old 09-24-2008, 06:41 PM
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Default RE: What engine do I need for maximum speed?

Jett 60 BSE LX in rear exhaust and full pipe with mid rise header.
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Old 09-24-2008, 07:34 PM
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Default RE: What engine do I need for maximum speed?

The Jett 60 LX is my favorite speed engine of all time, there is no substitute. Can start it up on the stand, set needle, sit it down and taxi out and takeoff and land like a sport engine!!! The Weston Magnum is a decent engine with decent rpm but way short of the Jett LX. One engine that i have experience with that is close to the Jett is the Webra 55 Speed. Strap on a Jettstreem tuned pipe and a 10 X 10 apc after correctly breaking the thing in and you have a real beast on your hands. I beat the nephue with the identical airframe with this engine., he is 60 LX powered. Yes, am a much older (73) experienced tretcherous old man, but could not spank him without a near equal engine. Would never try to run a 10 X 10 on the Jett as its just too much prop, how the Webra does it is beyond me. The Jett 60 LX is still my weapon of choice, but for a reasonably cheep scooter, the Webra 55 is very good. Do not confuse the 50 and the 55, they are nowheere near equal. I will run the 55 until the gang is able to beat me (very soon) and then strap on the 60LX for a few more months or years as it may be. ENJOY
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Old 09-24-2008, 08:42 PM
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Default RE: What engine do I need for maximum speed?

I have a well seasoned Sport Jett .50 on mine and hit 159 at our speed rally this summer.
My buddy has a .46FX with a Nelson pipe on his and is not too much slower.

Either one will impress the park flyers.[>:]
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Old 09-24-2008, 08:42 PM
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Default RE: What engine do I need for maximum speed?

With a tuned pipe or a red Jett muffler a Webra 55 will turn An APC 9X10 at just over 16K on 10% MAXIMUM nitro content and that combo is what I run on a Viper and one of my Diamond Dusts. A bit less RPM on 0%. Running more nitro will blow plugs until it looses compression due to a hurt piston or the connecting rod ends are elongated enough to reduce the stroke, not good! 15% nitro also may have contributed to the breakage of two cranks that I know of. Probable detonation.

The Webra 55 is a very powerful, light and reliable engine if broken in correctly, light load prop at a rich two stroke at WOT.

I'd reserve the APC 10X10 for a Jett 90 LX at 16 K or the OS 55 AX and red Jett muffler at about 13.800, in both cases that prop would only unload in a real clean plane.
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Old 09-24-2008, 08:48 PM
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Default RE: What engine do I need for maximum speed?


ORIGINAL: krkenned

Bob,

I have been looking into the Jett 60LX. I would like to get the FIRE engine however, I don't think it will work with the Magnum fuse. Are there any differences in performance in the FIRE and normal side exhaust engines?
It won't stock, but the Magnum begs to have the canopy ripped off and a new one molded with a pipe tunnel and engine cowl. I have a second Magnum for just that purpose but I still haven't started that project.

Beef up the elevator hardware, which can be as simple as replacing it with better quality but equivalent stuff. There are known cases of Magnums losing the elevator (that's a bad thing) with stock elevator pushrod assemblies. Not a rampant problem, but worth knowing about at least.

And run the CG at the rear of the recommend limits. The recommended limits go from very nose heavy at the front, to less nose heavy at the rear. Mine's at 145mm I think, but I'd have to go check.

Oh, and this is a personal thing, but that stock color scheme sucks for visibility and orientation compared to a few other color choices. The checkerboard looks fuzzy grey at distance. If your eyes are decent and you don't have orientation problems, it'll be fine. Plus, the trim peels off too easily. It's fine until a corner lifts.

All in all it's a good airplane. You ought to consider a bubble-free tank. A Jett 8oz slim tank fits nicely, with a wee kiss of the Dremel on the former at the wing LE root.

MJD
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Old 09-25-2008, 11:34 AM
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Default RE: What engine do I need for maximum speed?


ORIGINAL: krkenned

Bob,

I have been looking into the Jett 60LX. I would like to get the FIRE engine however, I don't think it will work with the Magnum fuse. Are there any differences in performance in the FIRE and normal side exhaust engines?
The FIRE only performs a bit better because it uses the full-size tuned pipe. But the performance difference is not that extreme. Going through the weight/hassle to install FIRE in the Magnum will not buy you a great deal of performance. And as some have noted, the side exhaust SJ-50 or SJ-60LX will keep you on your toes as it is.

If you were building the airframe from scratch or a kit ..... then yeah, incorporate a pipe tunnel and have at it.

One Magnum someone showed me with a YS 45 RE on it showed some ingenuity - he rotated the engine installation about 45 deg, riser header, ran the pipe down the side of the fuselage. That is one approach that some folks reading this thread might consider. (no, I do not have a photo of it).
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Old 09-25-2008, 12:26 PM
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Default RE: What engine do I need for maximum speed?


ORIGINAL: bob27s
Going through the weight/hassle to install FIRE in the Magnum will not buy you a great deal of performance. And as some have noted, the side exhaust SJ-50 or SJ-60LX will keep you on your toes as it is.

If you were building the airframe from scratch or a kit ..... then yeah, incorporate a pipe tunnel and have at it.
You're quite right, making the tunnel would really just be a fun little project. If one isn't doing it for the amusement value as much as for a the possibility of a small performance gain, then it truly might be a waste of time. In such a case, start with a better airframe from the get-go - Matney Zoomer, whatever..

Myself, I figured on doing it just because it is a nod towards what the aircraft really could have been. It goes like snot with a side exhaust engine, and if it is the first aircraft a guy ever flies at these sorts of speeds, it is plenty enough as is! It is not slow, while at the same time it is NOT a 200mph airplane as Weston implies. Except perhaps wound right out in a dive. But 150 and a bit more, yessir.

krkenned: the nice thing about a Jett FISE is that if you crack up the Magnum, you still own a very powerful, durable, and versatile engine that throttles wonderfully and that is well suited to many other projects. The West .50 handles really well and is a bear for power too, but is slightly more limited in prop selection and application - I guess you could say it is a bit more high-strung than the Jett. Can't speak about the Rossi, don't own one.

MJD
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Old 09-25-2008, 10:55 PM
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Default RE: What engine do I need for maximum speed?

The rossi .53 is limited on power/RPM. I had one on a viper, and it would not get on the jett SS pipe. I called Dub Jett about the pipe and prop combo I was running. . I tried smaller props on the Jett SS pipe, and it would not get over 16.5k on the ground, and it would not get on the pipe in the air. The Rossi .53 does not like RPM over 16k. Ended up using the regular Jett red pipe and an 8.8x 9.25 prop to load it. It liked the load, and it would stay just under the 16k mark where it could breath.
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Old 09-26-2008, 10:03 AM
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krkenned
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Default RE: What engine do I need for maximum speed?

Thanks for all the recomendations and help. It is much appreciated.

Does anyone have any experience with the Magnum XLS-52? The specs on that engine show up to 18,000 RPM, though I know the specs can be exagerated a lot of times. I am probably going to start out with a lower price engine and then move into the Jett 60 LX after I get the feel of the plane. I currently have a few engines laying around collecting dust (46FX, 46AX, 55AX, Tower 46) and was going to start with one of these but just came across the Magnum 52 and for 89.99 I may give it a try.
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Old 09-26-2008, 10:50 AM
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Default RE: What engine do I need for maximum speed?

You would be better off just running the OS46FX that you have. Save the money.

You can even use the muffler from your Tower .46 on the OS .... bolt on a 9x7 prop so it turns up. Might impress you. Adds about 600-800 rpm.

Or invest it in the full blown tuned muffler or a pipe. Ads 1500 rpm.
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Old 09-26-2008, 07:13 PM
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Default RE: What engine do I need for maximum speed?

....yep. I agree with Bob....save your money for right now. Put the tuned muffler from the Tower
on the OSFX, and let 'er rip.

FBD.

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Old 09-26-2008, 07:50 PM
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Default RE: What engine do I need for maximum speed?

I have a Weston Magnum with hundreds of flights on it. I run a OS 46 AX and a Mac 8.5cc tuned pipe. I run the APC 8x9, 9X8, 9X9, 8.75X9.0W PYLON. 30 % nitro. With the 8X9 I can get over 18,000 RPM static. Of course it really unloads in the air at least another 3-5 K. (Especially in full throttle dives!) This motor pipe setup is so reliable I never really have to touch the needle or worry about a flame out. It takes about a minute for this motor to warm up and then it runs exactly like an electric motor. The only thing this motor occasionally needs is new glowplug. UNLIMITED VERTICAL and great top speed. The photo is old, my header and pipe are both shortened to the max now.

EDIT;
Actually, I flew it yesterday and threw the tach on to see what it was turning for the purpose of this thread. I saw just over 19,000 rpm for a moment with a 9X8 APC. Didnt touch the needle.
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Old 09-27-2008, 04:41 PM
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Default RE: What engine do I need for maximum speed?

Turbo442 - Nice Glock............

Maybe we should have a speed planes and guns thread.....
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Old 09-28-2008, 03:47 AM
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Default RE: What engine do I need for maximum speed?


It won't stock, but the Magnum begs to have the canopy ripped off and a new one molded with a pipe tunnel and engine cowl. I have a second Magnum for just that purpose but I still haven't started that project.
MJD
I was thinking the same thing. I have a k&B 7.5 fan engine front carb/rear exhaust that would work nicely. It has the perry pump and carb.
Some times I wish my magnum had retracts. It would be a nice challenging plane to do touch and goes with.

Maybe I will build a 3/4 scale magnum out of depron, make it electric, build in a set of retracts into it and paint it yellow.

Matt
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Old 09-28-2008, 09:26 AM
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Default RE: What engine do I need for maximum speed?

Hey 573,

Must be something wrong inside your 53 , 16000 rpm sad !!!!

I turn a 8.8x8.75 at 19200 rpm on the ground, my viper is good for 150+ mph.

You got to lift the exhaust timing - open the exhaust all the way- then stick a Jett pylon/racing short pipe with adapter, you may want to consider smoothing the exhaust transition in the adapter as I did on mine.

Next thing is get a 45 head and swap out the 53 , the 45 head has higher compresion, ( I have many rossi parts to mix and match )

Now get a carby off Jett with the largest ventury possible , I think mine was a 12 mm from memory, this will let the air in and still give you a good idle.

Plug is a siggp002 tuned pipe , sigg products and they are $6 bucks or so,

Fuel is 5% coolpower,

All this will wake your rossi up , I've been playing with these things for years and are a powerhouse engine if worked over.

My viper is for fun only , gave up racing due to the politics - that takes all the fun out of things.

Have fun .

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Old 09-28-2008, 02:16 PM
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Default RE: What engine do I need for maximum speed?

I saw this picture of someones elses magnum you might like.



My magnum however has over 153 on it now with weston50v1/tuned pipe


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