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Simonini mini 2 plus


learner_driver
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Hello

a few questions to other pilots of this motor.

first off I was told by Geoff from Paramotors uk that other pilots get 3litres / hour out of their simonini's which I thought was a bit low on the consumption side. I did not buy it from him

with a 9 litre tank I was thinking even if wrong I will get 2.5 hours.

1 hour 45 minutes later I was standing in some ladies garden, who I offered to photograph her ........... house as a guesture of good will. :mrgreen:

I will know that she likes me, if she appears naked outside. :acro: anyhow moving on.

I fitted a Tiny tach. and on cruise it shows 5010 with the 130 prop and I can just about go full trimmers out.

however full power is only 5600. I have a feeling it should be more like 7000 rpm.

So at 5000 rpm I killed the motor last time and the plug was a lovely light brown.

I am confused,

the fact that I can't rev above 5600 surely means its running too rich ? the consumption of 5.3 litres / hour would support that

the fact that its light brown on the plug surely means its running correct ?

its a walbro 32 carb - I think

I also think that the low is possible slightly too lean as it bogs slightly when you gas it. ( but this could be due to the heavier 130 prop)

could it be too lean on the low to rich on the top

any ideas other experiences

cheers Simon

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I recon you need a bigger wing mate.

:lol:

Just about every time I have landed out, I have met someone nice who waqnts to help.

It can be a great way to find new sites.

SW :D

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The Mini2 claims consumption of 2.2 lph @ 5k rpm, but this is likely an UNLOADED measurement.

Redrive makes as much difference as prop choice, but they both affect the engine loading in similar measure.

For example, my stock mini2 engine came with one of the redrives list on:

http://www.simonini-flying.com/mini2plus_eng.htm

But when I computed my max rpm, I was only getting 16HP out of it. Insufficient but great on fuel.

See:

[youtubevideo]

[/youtubevideo] for the video example.

With this setup anything over half throttle was just extra fuel that cooled versus burnt.

The Mini2 can make 200lbs of thrust properly matched up with a 3.1:1 redrive a helix triblade and 7500 rpm.

Some folks say OMFG that's too much power, but I say they're simply mass challenged and welcome all the jam I can squeeze out of my motor.

I fly a 14L tank and see 3+ hrs, although not regularly because I like using the Jam versus boating around.

Tune can drastically affect consumption in a 2 stroke - I recently adjusted the bing jet needle one clip richer and then burnt 5 litres in under an hour as it was four cycling (nice cool EGT tho) in midrange. That's an undo setting worth trying once.

I would hazard a guess that a wing on slow trim burning fuel only (vs thermal) could expect 4lph consumption with a mini2 assuming wing loading not too far outside upper placard. So many variables tho that is really just wild speculation. Start squeezing the fun lever and out the window goes your consumption curve, but then you knew that from practice.... ;-)

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thanks for the info Mr Andrews

small update

if this is my carb and it looks identical matched with the engine

http://www.poweredparaglidingontario.com/improvements/carb_adjustment.htm

then I can report that the low is exactly as factory default and the high is slightly richer

it the article it says default (always rich) 3/4 turn from the seat for the high screw. mine is another 1/8 turn richer. Perhaps this could account for the low max rpm?

come home Pete

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All membrane carbs require preflight adjustment for optimum power.

Someone may look for exception to that, but humidity, temp, air pressure all affect air density and therefor fuel mix.

Procedure is full throttle adjustment to peak rpm, then dial it back in rpm to ensure sufficient richness for engine longevity.

That is easier said then done, and I bet many (most?) folks do not touch that High screw to tweak it.

I know some pilots that are afraid to because it "came that way" and fly only after a protracted running period if at all when a small adjustment would give them all the gumption they've been missing.

To each their own.

I fly a bing carb on mine, so don't adjust much nor often.

Your max rpm could be limited by prop, redrive/prop, carburetion or any combination thereof.

In my video above the LARGEST factor was redrive/prop since they can't be considered separate in my example.

With installation of a 3.1:1 (factory WJ) I saw 7400+ rpm on the same prop because the HP curve matched better.

It's a balancing act.

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Blocked exhaust - good point.

I too saw at least 300rpm less after break-in oil plugged my silencer packing.

I added a "bypass hole" down the middle when I repacked it and it winds up as it used to.

300 rpm doesn't read like much, but it's at the top of the "butter zone" for takeoff.

You sorely miss it when you know what it should be like.

Not easy tracking down a problem that ever so slowly compounds itself with no large clues.

So yes, pull your silencer if in doubt and try it. One can live with the noise for a test.

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Good idea thanks Lads.

I will try tuning the top screw 1st. I just need someone else to help me hold it. as I have technically lost 1400 rpm from what the machine is capable of 7200rpm.

I have fitted a larger prop I can understand that it may drop by say 4-500 rpm but I have still 1000rpm missing.

thanks

Simon

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I do believe you could get down to a burn of 3 litres an hour with the mini 2 plus if you were about 13 stone in weight. I'm 16 stone and have achieved 3-3 litres an hour regularly. Using an overloaded Atis 2 wing (Sky paraglider) and a redrive of 3-1/1. The wing's rated to a max of 110 kgs for freeflight and I'm AUW of 150 kgs ppg. It manages it well with easy tkeoffs and landings and I even have trimmers for more speed at altitude which dont make a huge difference to the economy (up to just over 4 litres / hour) and speed to match a correctly loaded Revo. And fun to chuck around, if you're that way inclined.

The mixture settings. The fast running jet is tuned for max revs and then opened anticlockwise about an eighth to a quarter turn on mine. The slow running jet is screwed in until pretty lean. To the point were the engine has to be warmish before it will pick up off tickover without bogging or hesitating too much. Then I readjust the main jet again and the low jet again because the influence from both overlap at midrange. I also found that, if midrange is a bit croaky, going in on the slow jet will smooth it out.

This is also using the walbro 37 carb, not the 32. If using my method please check it out with Pete or someone to make sure it's running good, but I did hear the 37 gives better economy and that's the only difference between mine and my cousins set up, apart from my 130 prop against his 125 and his redrive gearing (ok. That's too many variables!)

Good luck

Dave

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