scale only 4 me

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I have a Fox 5.8 on a 33% Extra,, What should it turn? I'm getting 5,600-5,700 static with a 26-10,, should I expect more??

pe reivers

It depends on what make and type of prop, and what make / type of exhaust system you are using.
The shortest questions often are the hardest to answer.
For a 100cc engine you seem to be low on power. Somehow the engine is stangled and is not allowed to breathe.

STUKA BARRY

Like what was said before, dont know wghat prop or exhaust, but if you swing a 24X10/24X12 Xoar, it'll come alive.

MetallicaJunkie

i hit mid sixes with my 70cc 3w twin on a 24" 3w props not sure it they were 8 or 10" pitch,,,, would it be safe to estimate the fox will hit mid 7s on a 24" prop?

scale only 4 me

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xoar 26-10, slimeline wrap around pitts,

I tried a Vess 26C also, but found out that's larger than the range posted on the fox site. I've tried a 22-8 top flight prop too, but no RPM increase,

I've tried adjusting the timing too, seam what ever I do it maxes out around 56-57, just wondering what I should be shooting for,, This is my first 95-100cc class motor and I don't want to go around buying props if it's not necessary

Thanks Guys

wesaysoracing

a prop?

MetallicaJunkie

so from a 22x8 to a 26x10 you saw no rpm increase[X(]? yikes thats strange

pe reivers

Did you tune the carb for best rpm with each prop? No change in rpm is very strange indeed. A 22x8 prop would suit a 45cc engine well! On most 100cc engines, a 26" prop is too small, so something seems out of whack here.

scale only 4 me

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I meant a 26-8,, not 22-8

pe reivers

will have to see how topflite equates to others.

edit:
checked it out: The TF has the same engine load as a Xoar for the same size, so the 26x8 should spin some 300 rpm faster if the carb is tuned well.

scale only 4 me

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300 more RPM than what? What should a Fox/Brison/Sachs 5.8 be able to turn?? around 56-5700 or more like 6500??

pe reivers

Don't
ask Fox!

Tired Old Man

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Single hole 5.8, well tuned, good prop, maybe 6k on a good day. Not having that second cylinder holds things back a bit.
So how well does it pull what it's attached to? That bears a lot more importance than some mythical baseline RPM value.

scale only 4 me

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It starts out ok, but soon acts like it's getting warm and does not have the power to do the job if I do to much vertical maneuvering,, sadly it doesn't seem up to the job,,, or why would I be here asking,,LOL

6k huh?? ok, it's close to that I guess

Thanks

Tired Old Man

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If it warms up too fast you need to look at the cooling side of the equation. They all drop power rapidly after a certain point.

scale only 4 me

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Should this handle a 30lbs plane?

The head extends outside the bottom of cowl almost completely, with plenty of exit behind the muffler, I don't think it's a trapped airflow problem at all

MetallicaJunkie

yes it an handle a 30# plane...based on Pe's calulator, a 26x10 spinning 5700rpm will give you about 35 pounds of static thrust... i believe your engine woud fly a 50# plane in a scale manner.... just look back at the glow days when planes were heavy and built like tanks and we;d slap a 40 or 61 and away theyd go

jedijody

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A 30#, 33% Extra? It's not going to perform anything close to what most modern 3D set ups will, it'll be a good sport aerobat though.

scale only 4 me

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Thanks for the insights guys,
It's an older very modified Lanier Kit, so it's heavier than a modern 33%, I'm not asking for miracles just wanted to know what I should expect from this size/type motor

Tired Old Man

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One of my early gas giants was a 33% Extra 230 with a 4.2 Precision Eagle. Weighed in a little over 28 lbs. It flew fine aerobatics but 3d was a non starter. Didn't have the surface areas for that anyway.

scale only 4 me

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The control surfaces have been enlarged on this one, but I do fear I'd need a lot more thrust to do anything 3D-ish

Truckracer

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I flew the heck out of one of those big Lanier Extras for many years. It started out with a Quadra 75 which was very adequate power though certainly not 3D like at all. But then that plane was never designed for 3D anyway. Later on a DA-100 was installed for a major increase in performance. I believe that plane weighed just under 30 pounds but can't remember for sure. It was and still is one of my all time favorite planes and one of the best snapping planes I have every flown. It is currently being rebuilt and put on a diet and will fly again soon with the DA in the nose.

I can't speak for the 5.8 but the big Quadra 75 would never pull much over a 24-10 or it was out of its power band. I wonder if you are over propping the 5.8 with 100 sized props? I know my smaller 3.2 and 4.2 Sachs based engines like to turn up for best performance ... maybe the 5.8 is similar in that regard. Are you sure the 5.8 is in good health? Good compression?

scale only 4 me

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I took the plane out again today and believe I've solved the issues, It's still *****g out around 5700 but it pulling fine in the air and not getting hot, loosing power or dead sticking etc. Actually had the first flight I felt comfortable pushing the plane and not worrying about the motor quiting.

I figured out why it wasn't responding to needle adjustments. Ends up the carb was clogged with something, I don't know what,, Kinds looks like varnish, It's hard and brittle when it dried out but it doesn't dissolve in the gas. I had previously cleaned the screen and blown out the ports, but I found gunk in the fuel tank that clogged things up again. Cleaned the tank, Took the carb completely apart again, reset the needles and it sounds and responds to throttle input much better now. I don' t know what this stuff was or how it got in the fuel tank,, I run filters, but there it was.

I think I'm going to the clear fugi bottle tanks for now on,, I may have spotted the gunk sooner

Thanks for the help guys

pe reivers

gas gum!

stevenmax50

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I have a 33% Lanier Giles 202 under construction.  I forget what the weight is supposed to come in at but I think it is near the 30# range.  I was just looking at the Fox website.  It seems That the 6.4 twin would be the correct Fox engine for this plane.  But it is around 400 bucks more expensive than a DLE or DA.  I would love to buy American.  Is this the correct Fox engine and is it worth the price???