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OS 1.60FX vs OS bgx-1 3500

Old 06-13-2008, 11:56 AM
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BankYank
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Default OS 1.60FX vs OS bgx-1 3500

Ok i own both engines. 3, 1.60FX and 2 BGX's and i find that the 1.60fx spins an APC 18X6W at 9k for flight, Cool...But both the BGX-1 i own will spin the same prop at the same rpm APC 18X6W at 9K. I have also seen 1 other BGX and read about yet 1 more that does the same rpm.
I would think that the BGX being a bigger engine should turn a 20X6 at 9k but no way will it come close.
With the 1.60 i have a lighter engine,uses less fuel, same power
The BGX runs fine,starts easy,idles great, and what feels like good compression when turned by hand. So i assume the engine's are in good working condition.
IS the BGX an old outdated design or something else? At the moment i don't see any advantage to the BGX-1 at all anymore over the 1.60FX
Pat
Old 06-13-2008, 12:08 PM
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mtwister
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Default RE: OS 1.60FX vs OS bgx-1 3500

The BGX was out long before the 1.60 FX, and you're right they spin the same props about same speed but the 1.60 FX is alot lighter. The BGX's still work great in warbirds where nose weight is desired.
Old 06-13-2008, 08:47 PM
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Default RE: OS 1.60FX vs OS bgx-1 3500

I have a BGX on the front of a WM P-51. Don't recall what the rpms are but I'll tell ya , its like a flying freight train and I mean momentum, not weight.
Old 06-14-2008, 01:41 AM
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Default RE: OS 1.60FX vs OS bgx-1 3500

I also have both 1.60FX and BGX. The BGX looses torque rapidly much above 8000rpm and will equal a 160fx at 9000 rpm with the stock muffler. The stock muffler has a lot to do with this because they share the same unit. The BGX will out-rev a 160 with a better exhaust and blow it away at lower RPMs. The BGX is best turning large props around 8000rpm.
Old 06-14-2008, 09:37 AM
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BankYank
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Default RE: OS 1.60FX vs OS bgx-1 3500

Yeah mine has a bisson pitts on it also. I can sure understand using it in a warbird for nose weight. It sounds like the 1.60FX will do everything the BGX will. Except spin a bigger prop at lower rpm and the 1.60FX can more then make up for that. I know it will spin a APC18X10 at 8,500k giving good speed on my P-51. It also uses less fuel and weighs less. At this point i just don't see a need to ever buy another.
Pat
Old 06-14-2008, 12:42 PM
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Default RE: OS 1.60FX vs OS bgx-1 3500

The BGX is hampered by restrictive rotor timing and low compression. Its lower than normal compression makes it love nitro and the short inlet timing keeps it from revving. I was able to improve my BGX a lot by opening the inlet timing and increasing compression along with a large volume cannister muffler.
Old 06-15-2008, 06:54 PM
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Default RE: OS 1.60FX vs OS bgx-1 3500

Kweasel, can you give me any tips on your mods to the BGX? I have one that a friend pretty much gave up on, since it really doesn't out perform the 1.60 by much. I'd like to bump up the power a little without affecting the idle reliability too much though. What is a decent prop for this engine?
Old 06-15-2008, 10:33 PM
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Default RE: OS 1.60FX vs OS bgx-1 3500

My first mods were opening the rotor timing from 173 degrees open to 181 by grinding the window on the crank to open 2 earlier and close 6 later. This did not have any effect on idle quality and is still milder than the 160, I later did a little more cutting but dont remember where I ended up. I omitted the head gasket, which didnt make much difference but certainly didnt hurt. This configuration ran great with 15%CP and had good fuel draw at 8200rpm with the carb restrictor in place. For comparison I used an APC 16-10, my 160 could get 8900 and my stock BGX did 9000 on the same day with the same mufflers. The inlet mod was good for an additional 300rpm and with the canister exhaust made 9800rpm. Best flying performance is with 18-10,12 or 20-8,10. Whatever tachs at least 8000.
Old 06-16-2008, 12:18 AM
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Default RE: OS 1.60FX vs OS bgx-1 3500

Ok! Thanks for the info. I will take a close look at the intake rotor. I plan on using this engine on a Skyshark Christen Eagle, unless someone here can talk me out of doing it. I think the plane needs the nose weight to balance, and I am hoping the power will be sufficient.
Old 06-16-2008, 07:01 AM
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Default RE: OS 1.60FX vs OS bgx-1 3500

I would refrain from modifying the BGX. Unlike the 1.60 the BGX is made for low rpm applications. A 16x10 is definitely on the low side for the BGX. Try using a 18x10, 18x12 or a 20x10 propeller with the BGX. You will get loads of thrust at a rather low RPM.
Old 06-16-2008, 05:54 PM
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Default RE: OS 1.60FX vs OS bgx-1 3500

Looks like I will have to get the old fish scale out and test some props. If it will pull a 20X10 without getting hot, that wouldn't be bad at all. I plan on getting the Bisson pitts muffler first and test it the way it will be on the plane.
Old 06-16-2008, 06:22 PM
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mtwister
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Default RE: OS 1.60FX vs OS bgx-1 3500

If you're going to run a Bisson, then you're pretty much guarunteed to require a pump.
Old 06-16-2008, 07:28 PM
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Default RE: OS 1.60FX vs OS bgx-1 3500

You can't run a pump with the BGX. It will make the midrange WAY to rich. With the bisson muffler i have not seen one have fuel problems at all. My engines will pull a 20X10 at 7,900 with out getting hot,,But from about 3/4 throttle up to wot nothing changes. The most pull i have managed to get from a BGX is with a APC 18X6W at 9k. The OS1.60FX spins the same prop at the same rpm for less fuel and weight.
Im working from memory
APC 18X6W 9K 17.13 lbs pull
MSC 20X6 8,100 16.3lbs pull
APC 20X10 7,900 15.9lbs pull

Please post your readings. Im sure others would love to see them
Pat
Old 06-16-2008, 10:34 PM
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Default RE: OS 1.60FX vs OS bgx-1 3500

The induction side of the BGX is the only area that is far outside normal design parameters. OS gave us restrictive rotor valve timing and an oversize carburetor, the result is less power and poor fuel draw. For comparison, a Moki has much longer rotor timing along with a smaller carb. Bringing this engine up to standards makes it noticably better. Perry pumps are not that great with these engines because they are not responsive enough, they run too rich at part throttle and tend to flood when the throttle is opened quickly.
Old 06-17-2008, 10:23 AM
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Default RE: OS 1.60FX vs OS bgx-1 3500


ORIGINAL: BankYank

You can't run a pump with the BGX. It will make the midrange WAY to rich. With the bisson muffler i have not seen one have fuel problems at all. My engines will pull a 20X10 at 7,900 with out getting hot,,But from about 3/4 throttle up to wot nothing changes. The most pull i have managed to get from a BGX is with a APC 18X6W at 9k. The OS1.60FX spins the same prop at the same rpm for less fuel and weight.
Im working from memory
APC 18X6W 9K 17.13 lbs pull
MSC 20X6 8,100 16.3lbs pull
APC 20X10 7,900 15.9lbs pull

Please post your readings. Im sure others would love to see them
Pat

Funny, on mine it wouldn't run with the Bisson muffler, and guess what fixed it? Gee, a pump. Now it runs like a champ. I just had to lean out the ls quite a bit.
Old 06-18-2008, 07:44 PM
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Default RE: OS 1.60FX vs OS bgx-1 3500


ORIGINAL: mtwister


ORIGINAL: BankYank

You can't run a pump with the BGX. It will make the midrange WAY to rich. With the bisson muffler i have not seen one have fuel problems at all. My engines will pull a 20X10 at 7,900 with out getting hot,,But from about 3/4 throttle up to wot nothing changes. The most pull i have managed to get from a BGX is with a APC 18X6W at 9k. The OS1.60FX spins the same prop at the same rpm for less fuel and weight.
Im working from memory
APC 18X6W 9K 17.13 lbs pull
MSC 20X6 8,100 16.3lbs pull
APC 20X10 7,900 15.9lbs pull

Please post your readings. Im sure others would love to see them
Pat

Funny, on mine it wouldn't run with the Bisson muffler, and guess what fixed it? Gee, a pump. Now it runs like a champ. I just had to lean out the ls quite a bit.
My BGX runs with the Bisson pitts, Without a pump, with large fuel line, klunk and tubing to the needle valve and standard tubing from nv to carb. Oh yeah, a little patience and tuning. So far pretty reliable.
Old 06-18-2008, 08:23 PM
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Default RE: OS 1.60FX vs OS bgx-1 3500

PMaxx, that is the configuration I was hoping to run mine in. What prop do you use on yours?
Old 06-19-2008, 06:53 PM
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Default RE: OS 1.60FX vs OS bgx-1 3500

So far I've used only an 18x6w apc. I only have about a dozen or so flights on it so I can't really make a reliability claim just yet. I can say however that when I changed from med. size tubing to large she ran a whole lot better. I have not tached it yet but I would guess a little over 8000 rpm.
Old 06-21-2008, 11:03 PM
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Default RE: OS 1.60FX vs OS bgx-1 3500

One of the biggest problems with glow engines approaching, or exceeding, 2 cubic inches of displacement is fuel delivery and the fuel itself. Carb configuration,intake venturi diameter, and exhaust diameters are critical to achieve appropriate backpressure and atomization/fuel delivery of fuel at the carb. The stock muffler is engineered to deliver the correct amount of backpressure while the aftermarket mufflers stray from the manufacturer's engineered design. Look at your aftermarket muffler and compare and calculate the muffler exhaust opening area to the stock muffler. If there is a difference, try to match the exhaust area as close to the stock muffler as possible. Another problem with big bore glow engines is that they do not like nitro, nor do they need it. 12-14% lube is more than adequate. I mix my own fuel that consists of straight methanol and 12% Klotz KL-100. I run a McCoy #55 plug. No problems. Your carb intake venturi diameter should not exceed 13mm and no less than 11mm. Do not use RPM readings as a guideline for power. There is no need to exceed 8,000 rpm on any large bore engine. I run a 19 x 8 3W at 8000 rpm on no nitro. Cut down on the lube and throw out the nitro and you will have a better running engine with smoother transition, better midrange, and easier to get a consistent needle setting. The most accurate way to get the most out of any engine, since they are all different, is to go to the field with your model, put on a prop and let it ripp. Running your engine static is a good starting point but getting a good engine to run good requires a lot of "static" AND "in flight" trial and error. One last comment. Remember this one. Your fuel delivery system can only deliver what can be pushed through the fuel inlet nipple on the carb! Hope I have been of some help. SG
Old 08-14-2008, 06:38 PM
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Default RE: OS 1.60FX vs OS bgx-1 3500

I have a bgx in a sundowner.
I originally flew this bird with a bolly carbon tuned pipe & she went good, sadly this fell off in flight, never to be found. Disgruntled I went to the stock muffler & the same 16x14 apc pattern , it was a little disappointing to say the least. Next I was offered a genuine os tuned pipe, the seller told me to expect up to 40% power increase, 'yea right' I thought, but the stock muffler was so sad that I had to try. She turned up in the post and sure enough the instructions included from OS clearly stated "40%" I now turn a 16x15 at 8200 static.which gives 140mph straight and level(via on board GPS) I fly at sea level without nitro. So I feel that maybe some of you are being a little hard on the bgx ? I just cannot imagine the 160 turning a 16x15 at 8200. I do stand to be corrected and Would be interested in your opinions.?

regarding props, landing gear swapped, so I now have enough room to swing an 18 incher, what would be an equivalent to the 16x15 ?

John
Old 08-14-2008, 06:42 PM
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Default RE: OS 1.60FX vs OS bgx-1 3500

for those of you who did not know what a sundowner looks like
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