Dustflyer

My Feedback: (13)

Did some more runs on my Jett BSE 60L FIRE and is now turning 16,000 with an APC 10X8 on Magnum 15% using a KB1L plug and MACS quiet tuned pipe.

Has anyone done better with any other 60?

ewspears

My Feedback: (12)

What does it do with an 11 X 7?
I have a couple of YS 60 FR's that I've raised the exh port .030" that both will turn an 11 X 7 at 16,000 RPM on 15% Fuel.

Dustflyer

My Feedback: (13)

Esten,

I don't know I haven't tried it. I didn't bother trying the APC 11X7 because it is substantially wider than the 10" prop and the pitch is just too low to get any kind of speed unless you are really turning some serious rpm.

If I am not mistaken the YS 60 airplane engine isn't made any more, is it? I wouldn't be surpised if blows away the Jett with a 10X8. Is there any chance you might be able to check it with one?

Also, how much rpm did you gain by raising the timing?

The main reason I was so interested in the Jett 60L was the weight, it is only around 13 oz I believe. Most 60's are quite a bit heavier, usually well over 20 oz. How much does your YS weigh?

If I decide to go with a heavier motor I can go all the way to a Jett 90 which only weighs 24 oz or so.

Frankly, it wouldn't surprise me if the YS out turns even the Jett 90 as I have heard the YS is a bad you know what.

I realize I've hit you with a lot of questions but you really have my interest with that YS.

Thanks,

Gene

ewspears

My Feedback: (12)

Gene,
Since I'm powering 65" WS 8# 80's era pattern ships, anything less than 11" dia wouldn't be enough thrust. Besides my hand eye coordination isn't really fast enough for those 80's era ballistic pattern ships, much less something faster. I've got a couple of Scat Cats I built and competed with 20 years ago that I wouldn't even attempt to fly!

I do still like to modify and test engines and the next time I am testing I will put a 10 X 8 on one of my YS 60 FR's and let you know what happens. I would guess about 16,250 RPM. Raising the exhaust port .030" and eyebrowing it does the following:
1. Engine needs to be run with tuned pipe & tuning more critical.
2. Adds about 400 RPM with 11 X 7

The YS 60 hasn't been made for 10 years or more but there are lots of them out there that a clean up and new set of bearings will put in good shape. ( Probably the most bulletproof ABC piston/liner I know of)

I haven't weighed one but They're not light! If you're looking for maximum power to weight in something larger than Nelson 40 & Jett 50, I would suggest you look at a Ducted Fan engine based on a 60 sized case. Maybe something like a Rossi 81 DF. If money is no object a Jett BSE 90 FIRE.

Dustflyer

My Feedback: (13)

Esten,

Thanks for that info.

Sounds like I'm getting pretty decent numbers out of my 60. The big feature of the BSE 60L is low weight, I believe it is only about 13 oz. To be turning roughly the same rpm with the bigger and heavier high-performance 60 sized engines is pretty good.

It would be cool to get another 400 rpm bump out of a timing change. I'll have to talk to Dubb about that one.

No question the Jett 90 is the ultimate for a Patriot. Once I get done fooling around with the 60L I might just go for it.

ewspears

My Feedback: (12)

Gene,
I just traded for a like new Jett BSE 65L. The guy that bought it new from Dub a month ago wanted to use it for 3D so he bought the small black "detune" muffler for it. He ran a couple of tanks of fuel through it and decided it was TOO LOUD, TOO POWERFUL, & TOO PIPEY for his use on a 3D Airplane. So I traded him a 90 4-stroke for it.
I've not run it yet but his description sounds right up my alley. I'll let you know what it'll do once I run it. First I need to get a header pipe for it. Do you know whether any of the Macs or Hatori Headers will fit or do you have to get it from Dub?

ewspears

My Feedback: (12)

GENE,
I just got through running the first tank of 15% Omega in my NEW Rossi 81. Turned an uncut APC 10X8 at 17400 RPM with Rossi straight tuned pipe at 17.0" (glo plug to end of converging cone) I haven't done any pipe tuning yet and it pulls onto pipe early without a struggle so I suspect optimum pipe length for this fuel & prop will be shorter and another 2-300 RPM can be had on the test stand. It may turn a 10X8 20K in the air.

It's built up on the Rossi 61 case and is certainly a lot heavier than a Jett 60 or 65L but it's also a LOT STRONGER!!!!

Dustflyer

My Feedback: (13)

Esten,

The 81 sounds like a monster, that's some serious rpm with that prop.

Thanks for checking it out with the 10X8.

maxtenet

Just curious!

I'm getting 16700 out of my Jett .46 with a 10/6 APC. With a .61 shouldn't you be getting a lot more?

Max

Dustflyer

My Feedback: (13)

Try putting an APC 10X8 on it and see what happens. It's a lot more prop. I doubt if you would turn over 15K with it.

Don't forget the 60 is not that much more displacement than a 46.

DarZeelon

The horsepower needed to turn a prop at a given RPM, grows as a cubic ratio of that RPM.

If a certain engine makes X horsepower and spins a given prop, at 10,000 RPM, then to spin the same prop at 20,000 RPM you need 8X horsepower.

Let me assume the Jett .60 makes 30% more horsepower than the Jett .46. In theory, it should be powerful enough to spin a prop, with 30% more load, at the same RPM as does the .46.

Alternatively, it should be able to spin the SAME prop at higher RPM, to the cubic root of 1.30, or 9.1% faster.
If a Jett .46 spins a 10x6 at 16,700 RPM, the .60 will theoretically spin the 10x6 at 18,220 RPM.

This is purely theoretical, because the Jett .60 does not make its maximum power at a corresponding RPM range.

Dustflyer

My Feedback: (13)

That sounds about right. An inch of pitch is about 500-1000 rpm. That's why I would think the 46 would have a hard time turning the 10X8 at more than 15K.

The 60L is an amazing engine. Only a big and heavy Rossi is a match for it, and only by a few hundred rpm.

The BSE 60L is incredibly small and light, the same weight as an OS 46FX and yet is nearly as powerful as a big Rossi or YS. That is pretty amazing considering it is so user friendly and ready to go right out of the box.

This is not to slight the Rossi or YS, they are fantastic pieces of machinery, but if you have the few extra bucks to shell out for the Jett you will truly get not only your money's worth but maximum power for the ounce.

maxtenet

Having owned a number of engines, I can agree. If you have the money,get a Jett. My .46 performs flawlessly and has for four years . At $225.00 it wasn't cheap but it starts immediately, no need to readjust and just flat out screams. I own around 70 .40-.46 engines. This is the best of all of them without a doubt. If you treat this hobby as the investment that it is, it's worth spending the extra bucks for the pleasure of truly enjoying trouble free high performance flying.

Max

DarZeelon

The Jett .61 is quoted on the Jett Engineering web site as spinning a 12x6 at 13,500 RPM.

The calculated output is 1.98 HP.

The Jett .60L is quoted on the Jett Engineering web site as spinning a 11x5 at 15,800 RPM.

The calculated output is 1.87 HP.

The Jett .50 is quoted on the Jett Engineering web site as spinning a 10x6 at 17,000 RPM.

The calculated output is 1.91 HP.

Would this mean the Jett .50 is more powerful than the jett .60L and only .07 HP weaker than the Jett .61?

It could't be, because Dustflyer tached the .60L at 16,000 RPM, with a 10x8, which calculates to 2.12 HP. Or could someone here be missing the point. After all 15.8K and 16K are very close and the output difference looks exaggerated.

Dub Jett, could it be that the RPM ratings you are showing in your own web site, are putting your own larger engines to shame?

bdtsr

My Feedback: (5)

I had a YS .45FR, on an open header (no pipe and very loud) it turned an APC 10X8 at 14500. With a properly tuned pipe setup, it probably would have turned about 15000. Fuel used was Omega 15%. You might want to play with header length to find the peak for the engine. Just keep in mind that all out rpm is great for racing, but not for sport or pattern. A broader, flatter torque curve will work much better. Just depends on want you want to do with the motor and plane.

Dustflyer

My Feedback: (13)

The 60L is not that much bigger of an engine than the 50. It is a long stroke motor designed more for torque than rpm.

The advantage of the 60 in my opinion was a little more torque to turn more diameter. It is not really an rpm machine. Larger diameter props are its forte. It won't turn a 9X10 much faster than the 50.

Where the motor really shines is with more diameter. A 60L turning a 10X8 prop at 16K generates boat loads more thrust than a Jett 50 turning a 9X10 at the same rpm. A 10X8 at 16K might not make for the fastest Whiplash in the world but I guarantee you it is the easiest to hand launch.

Assuming you are not trying to move a lot of weight a Jett 50 turning a 9X8 at 18,000 is obviously a better choice for speed.

The other prop I really liked with the 60L was the 9.5X8.5 APC pylon, it would turn it around 17.5. I didn't try it but I would guess the 50 can't turn as much with that prop.

For whatever reason I found my Jett's would turn at least 400-500 rpm more on Magnum 15% sport fuel and a KB 1L plug. If you are using different fuel and plugs you may not get the same results. I also used a MACS quiet pipe that I tuned in 1/4" increments so I had things dialed in pretty exact.

ewspears

My Feedback: (12)

I just finished setting up my Jett BSE 90 FIRE. Running it static with Macs #1190 Tuned Pipe on my PSP Test Stand (Great test stand ) Engine has been modded lightly. Fuel used 20% Omega.
Ambient 88 degrees, 90% Humidity at 70ft elev.

APC 10X8 = 18210 RPM, Pipe at 17.0"
RevUp 11X7 = 17310 RPM, Pipe at 17.25

These are stock uncut props. I expect to be able to bump those numbers by about 250 RPM with 30% Nitro! Pipe dimensions are from glow plug to end of converging cone.

I plan to mount engine upright in Patriot and run pipe in a fuse channel. Won't win any scale madel contests; BUT IT SURE SHOULD BE FAST!!!!

By the way, This is the very same engine that MGlavin thinks would be outrun by YS 110