I'm looking at purchasing my first genuine 2m Pattern Plane. The Manufacturer suggests a 26cc Gas engine but I am not sure about one meeting the noise requirements for F3A pattern.

I am looking for suggestions on an equivalent Glow engine. I am considering a YS 160.

Any Suggestions or input? (Do you think a small gasser will be quiet enough? my smallest gasser is a DA50 and I know that isn't quiet enough with the stock mufflers).

That YS 160 is also going to need an aftermarket muffler to meet F3A noise limits, along with a soft mount and careful prop selection. F3A noise limits are so low that electrics have got hit with excessive noise downgrades in their scores.
Are you really going to compete or are you just going to fly it as a sport plane? You may not be able to make the weight limit with a gasser but that doesn't matter on a sport plane.

What a bunch of BS. Someone needs to tell those no noise freaks to go jump in a lake. Who cares if the airplane makes some noise, its an AIRPLANE. As long as its not ear shattering a little engine noise does not hurt a thing. Whoever made up noise rules like that needs to take up golf, and not be flying model airplanes. People really need to put those kind of control freaks in their place and tell them to get lost instead of bowing to their every whim.

Put a Zenoah G-26 on your plane, and dont worry about a little noise. You will be much happier and fly a lot more with a Gas engine instead of glow.

JettPilot

Oh Yes - I hear you loud and clear on that one Jett.
Unfortunately, as I will be competing with this plane I must abide by the rules.

I have 50cc - 150cc Gassers in my IMAC planes and some other sport planes so I at least I get to have my Gasser buzz that way.

I will use an aftermarket muffler. When I was in the US recently I saw the "latest" exhausts that were like a "T" shape sticking out the bottom of the fuselage - I can't remember the brand but will be chasing one of those units when I order the engine (providing I don't go electric) .

The electrics have a weight disadvantage in that they get weighed with the batteries in place whereas the IC ones ones get weighed with the tank empty. this could be the difference in fitting beefier control linkages etc.

The Ys 160 Dz motor and for that matter the Os 140rx are more power than any gas burner that i know of for the weight. if you are going to run a two blade prop try a 18.1x10.1 APC Depending on what class you are flying the noise rules may or may not need to adhered to. in the states local contests don't worry to much about the weight it does matter at the nats. FAI gets sound checked before each round. yes the ys will need a muffler and a header and the OS will need a header and a tuned pipe. But be prepared both motors will gobble up a gallon every nine flights. AS long as you keep the weight dry under eleven pounds both engines will have more than enough power to do everything with the YS being stronger to counter high winds hot humid days with some extra oomph. burns mor fuel and more expensive fuel at that though.

Dennis

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Well that's simple to overcome. Just discharge the batteries before the model is weighed.


Ed Cregger

The YS 1.60, or even the YS 1.40 Sport will be considerably more powerful than a 26cc (1.60) sized gas/petrol engine. A proper replacement (the same or more power with much less weight) would be a .90 - 1.00 two-stroke glow engine, or a 1.10 - 1.25 four-stroke glow engine.


Ed Cregger

I'm sure that a smaller 1.2 FS or .90 two stroke would be adequate for sport plane use, but if you are competing, you better use what your competition uses. There is a tendency in competition, not just F3A, to blame the equipment though. A thousand buck investment in practice time, fuel, and possibly even a good coach, will do most people a lot more good than trading in last year's equipment in for the latest and greatest.

Another question is can you keep the weight under 11lb, and will it have enough power. I have seen an MVVS 160 with a pipe make weight and perform acceptably well. It was not as good in any catagory compared to a glow powered setup, except for fuel cost. Lower lever competition usually has easier noise requirements.

Ok
Thanks for the input so far people
I can easily keep the weight below 5kg (11lbs) with a glow setup. I think that I will be heading the YS route but will now have to think about which one (Maybe I should use this as an excuse to buy one of each size - just don't tell the Wife).

This plane will be used in competition - I'm hoping it will see some FAI level (I practice flying the P07 pattern with the existing planes now but they are also used as sport fliers and have had a few repairs on them).

I'm not too worried about fuel cost - Between myself and the two teenagers, we go through over a gallon of fuel per week now just in our sport fliers (one of the benefits of having an RC strip at home). Maybe I will be able to get bulk purchasing discounts for the additional fuel usage that this plane will give. (If we like flying it I will probably end up getting three of them over the next year - one for each of us).

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I haven't seen a 26cc gas engine that can keep up with a strong glow .90 two-stroke or 1.10 - 1.25 four-stroke. Of course, I haven't experienced that little 3W engine that folks rave about. Maybe that one could keep up.

I'm with you on the practice being by far more important than the equipment, as long as the equipment functions reliably.

A good coach can be very difficult to find. I had two terrific coaches when starting out in pattern - but not much money and not much time when working as a Draftsman in the day time and a musician during the evenings. Plus, while I can build a flyable sport or fun fly plane, I do not build well enough to produce truly competitive pattern aircraft. Hey, you can't do everything well...<G>


Ed Cregger

Ed,


Calculating from the specific energy and the stoichiometric ratio of gasoline vs. methanol, the glow variant of an identical engine, will make 20% more power than the gas variant of the same.

There are only few engines that offer glow and gas variants and MVVS 26 and 35 cc are among them.


This power difference is partially counteracted by the fact that the gas version will need to carry 60% less fuel for the same flight duration. The RPM difference on the same prop will be that the glow version will spin it 7.7% faster than the gas version.

Just discharge the batteries before it's weighed. Without a doubt that will be the funniest thing i hear all day. Thanks for brightening up my day

Dennis

In real world numbers my MVVS 26cc gasser turns Menz S 18-6 at 8600 rpm and my new ASP 180 fs turns the same prop at 8350 rpm. Not many 91 twostrokes or 100-125 fourstrokes will follow that MVVS gasser. Weight is another matter though

Actually, I was going to use LiPo's but even after charging them for a long time - they still look like they're "Flat"

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I am an MVVS 26cc/Evolution 26 GT fan too. I've owned several MVVS 26 engines and I presently own the Evolution 26 GT engine.

As we all know, how fast the prop spins is only 1/2 the equation. Weight is another. In terms of thrust versus weight, I doubt if there is much difference in the end result between a strong .90 - 1.00 two-stroke glow engine. One thing for certain, the glow engine will turn inside of the gas/petrol engine's radius every time, due to lighter OAW.

All of us know this, so I'm wasting the skin of my fingertips typing it. <G>

All of you should know too that I like to use a gas engine whenever possible. Getting a gas powered anything to come in at under 11 lbs. is going to be tough.


Ed Cregger

I don't have any experience with gassers under 50cc so I am in unfamiliar territory when we talk about 26cc ones.

I've decided to definitely go to the Glow 4stroke route but having listened to all of your good input regarding the size, i now need to think about which one.

Remebering that this is for a pattern plane that will be used in competition

My choices are
Saito - 1.25 or 1.50
YS - 1.10, 1.40, 1.60

I'm leaning toward YS 1.40

Ed, my goal is to get in at about 10 lbs, maybe 11. I have on hand the Edge540 26cc from Peak. It is supposed to weigh 4 kilos with the SPE 26 and my MVVS is about 400 grams more because of the tuned pipe. I think I will stay just under 5 kilos and have about 8-9 kilos of pull. That should be fun! I will not maiden it until next spring because winter is bad around here

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That sounds like a nice combination.

The one thing that gasoline fueled engines can give us (not all do) is more running consistency than glow engines generally provide.

I am a Saito engine fan, but not for anything competition/pattern. For that purpose, to me, the only glow engine worth consideration is a YS or some of the made for pattern OS engines. Yep, there is a new Italian engine line that some folks are raving about and that I cannot remember its name. Is this a flash in the pan or something that will be around for a while? Only time will tell.

I would love to have been (won't happen in this lifetime) the first FAI competitor that placed well with a gasoline fueled engine. That would have been a kick.


Ed Cregger

My Zenoah G-26 puts out more power than my Saito 150 ever did...... Switched them on the same airplane, the Zenoah performed much better

JettPilot