we have tachs that plug right in to the new ignitions. I will have to check what the signal is.

Matt,

I tried the 17x12 on mine and it was just a teensy bit too much. Interested to see how yours performs today.

Close to 90 degF and humid today (as you no doubt know!!) and didn't touch the needles. Excellent performance with the 15.5x12W - identical to when I tuned it with the temp in the low 50's, again in the mid 70's and now today. Good pace with the plane, still unlimited vertical and not a hint of overheating. The buttonhead screws on the header were the last piece of the header/coupler/pipe puzzle. Rock solid.

Finally, a bulletproof set-up! This puppy is dialed![sm=thumbup.gif][sm=thumbup.gif]

Today's flying was much more than just a couple quick flights. I was to meet Ed at Jim Martin's field this afternoon but I had early trouble with my elevator pull-pull cables...I must have jammed the elevator putting it into the van and the down side came loose. By the time I got that fixed and got on my way, Ed called saying he was on his way back home. Not a good way to start the afternoon.

When I got there, Jim was packing up, so I asked if I could have a tankful of his 100LL Avgas. Changing nothing in my settings, I started the engine and took a quick hop. The mid range was extremely rich but the top end was pretty good so I made several passes. After a couple minutes the engine died for no apparent reason. Investigating, I found that my check valve that I've used forever on the vent line, simply stopped working. OKAY THEN!!

Restarted with leaner low end and very slightly richer top end and took a whole flight. Very interesting results. Engine was back to its normal self on the 18.1x10. Extended vertical was ever so slightly worse than when running the 87 Octane regular gas but no sagging noted.

Decided then to try the 17x12 apc which is a standard we all understand in pattern. Took a very quick hop because the low end went fat again. Landed and leaned it out a small amount plus richened the HS needle some more. Much better but still not quite there using the 100LL. Talking with Jim (who has flown CDI stuff for many many years) we realized that the 100LL retards ignition just a little too much. If we had a CDI unit that automatically advanced ignition a couple degrees, we would be able to run a fatter midrange and drive more power in the midrange. Ed, there's an opportunity there buddy!!

Learned a lot: 100LL Avgas smells great and has more than enough pop. Requires different set-up than 87 Octane regular gas. 100 LL retards ignition too much as is....I think a mix of 87 and 100 could be just the ticket, unless there is a 90 Octane Avgas altrenative. The 17x12 was turned superbly, just like on glow. 100LL Avgas runs cooler in the engine, but Jim thought that the flame could be propagating into the pipe more and to keep an eye on that.

See, high Octane burns slower than low Octane does so the indications of retarded ignition is on par. Since it burns slower, it is reasonable to assume the burn could be proceeding out into the exhaust a little. However, the engine was pretty cool when checked after landing, even in 90 degree conditions. There's an awful lot going on in there.

If anyone gets a chance to try 93 Octane in a piped set-up before I do, please report your findings

Bob,

Great stuff!!

The 17x12 was tried on 100LL Avgas with DelRey 50:1 synthetic. Once the needles were reasonably close, I took one whole flight and did do one extended vertical just to see. Engine is not fully run in by any measure but it held well for probably 600-700 yards straight up...practically no sagging to speak of. I also did some higher G stuff on shorter verticals, like multiple snaps. Nothing out of the ordinary noted. Behaved like a well tuned glow set-up

I think that the fuel and set-up need just a bit more tweeking.... we are nearly there. I also think that we may have found a way to get more pop in mid range...., we might be able to run a fatter midrange and get the pop we want with higher Octane gas. I'll tell ya I having a ball with this ignition stuff

...yes...Matt exactly. The only time we recommend running a higher octane is if you have a marginal cooling situation or you are in extremely hot weather.

One of the reasons they use 100 LL is for detonation and pre-ignition prevention. Most modern car engines use 87 octane fairly easily...even in hot environments as they have fairly sophisticated knock sensors and fuel metering and ignition timing control.

Using 100 LL virtually guarantees you wont have any problems like that in full scale aircraft. Weighing out a bit more power and cheaper gasoline vs engine longevity and possible detonation....the 100 LL is worth it in full scale as one can imagine. Your life is worth money...and also full scale aircraft engines are very expensive to overhaul/repair.

One other thing I learned today is that Avgas stays fresh for very long time in the can. It is designed to do that. Cargas on the other hand is only fresh for maybe two months. I also love the lack of smell...The down side according to Jim Martin is cleaning the plug every 20 hours of operation due to lead deposits. After all it is Low Lead, and not No Lead....But NO Lead has been mandated by the FAA and is coming. The designation is UL like 100UL

I don't like running the low end so lean just to make the engine run. Down to 1 turn open on LS needle. To get power you gotta have fuel, not to belabour the obvious.

The blended fuel experiment needs to be made simply to add to the knowledge base, but isn't practical for everyone.

As Todd says and recommends, 87 Octane regular gas is the best all around solution.

FWIW, I am having excellent results with 89 octane pump gas.

The thing I like about my current set-up is that it would be super easy for anyone to replicate... everything off-the-shelf, straight up, no special handling.

Something to be said for K-I-S-S!

.

Bob is exactly right....It may be time to summarize the findings:

We have developed a pretty good cookbook recipe for success with this engine:

Pipe:
ES 30G or 40G; set the baffle at least 27" from the plug center, straight line

Header:
Macs 2 1/4" rise for the OS 140; holes drilled out to 5mm and the clearance holes cut to 8 mm

Fuel:
Regular gasoline with Amsoil Saber pro, or other reputable synthetic, 50:1 to 100:1 mix ratio

Props:
18.1x10 apc; the latest finding is Bob's 15.5x12W; the venerable 17x12 works well also

Ignition:
One may use a separate battery and switch harness but most of us are using Ed Alt's Ignition Battery Eliminator and plug it into a switchable channel on the RX. One turns the ignition on or off using the TX when using the IBEC

It's that simple.

I intend to continue experimenting to try to find the outside edges of the running envelope. But in meantime, anyone who wants to have immediate success with the SAP 180, use the recipe above

Matt,
With the 100 octane fuel you could probably increase the compression slightly. I don't remember what the C/R of Todd's engine is - I'm sure he can tell you. Higher compression is generally good as long as you have the fuel to support it. It sounds like you do. A higher compression ratio generally increases efficiency. The only GOOD reason to run a lower compression ratio is to allow you to use lower cost (low-octane) fuel. Simply running high-octane fuel without making any other tuning adjustments (besides mixture) will NOT increase power output. To get more power while using high octane fuel (compared to running lower octane fuel) you would need to increase the compression ratio or increase the ignition timing (as you've already suggested).

A good ignition with an adjustable / programmable timing curve would be nice Ed.

John Pavlick
Team Black Magic

Hi jrpav1

You are right, with 100 octane fuel the compression ratio should be around 10:1

Regards

With the 100 LL you can also bump the time up a couple of dgrees which will give you a little more top end .
You can do that by moving the pickup from 28 degrees to 30 with out a detonation problum due to the lead and octain rating.

Gordon

Hi Gordon,

Ther are a lot of things one can do generally speaking. Increasing compression ratio by reducing trapped volume and re-shape cylinder top may give you a beast to tame. This activity is for people with special knowledge. Timing will also play a major role in this, low timing gives a torky engine, high timimig gives you a reving engine. But we are now at a certain distance from a friendly everybody's engine.
By increasing compression you may also get an engine that need redesign externally because of excessive heat. Total heat= compression heat + combustion heat.

I think MTK et al are doing the right ting by reporting a set-up that are for everybody that want a gasser.

Best regards

Yes exactly!!

Anyone who wishes to play with gasoline is best served to use the recipe we have developed.

Playing with machining of the head for more compression and so forth, may not for the everyday modeller. As far as I am concerned you would be on your own and please, if you break the engine doing special mods, don't cry to Todd about it. I can appreciate changing sensor positioning a little if you know whch direction to change it, but that might be all an average fellow may want to try

Reading back on some of the findings I have made and reported herein, a couple things might be considered a little over the top and not for the average modeller. I am going to stop posting such types on this thread. My apologies to the group in advance

Having flown the engine a bunch of times now in pretty warm to almost hot and humid weather I can say with certainty that the engine is extremely strong in all weather conditions. I'd say the output is ever so slightly lower under the 90F temperatures this past weekend, but not enough of difference to see a difference in the flying. It is at least on par with glow engines of similar displacement in the amount of power drop in hot weather. It is also extremely user friendly in hot weather just as it is in colder.

I am more convinced than ever this was an extremely worthwhile experiment and time very well spent. I am pleased that I made the transition from glow

Matt,

No need to apologize!

You've been a fountain of information and a great help to all of us, always there and ready to assist! I for one want to continue to hear about the more esoteric advances you seasoned guys are able to come up with. I may not be able to take advantage of them right away, but they are things we may need for the future.

At this point, I am quite satisfied with the result as is. (Well, I've still got to try that 16x12 prop...) I have been looking forward to having an economical 2-meter pattern plane since 2007 when several of you were trying to get a good result with the ZDZ 40 F3A. I was more than a bit disappointed when that didn't pan out, and there was much excitement when Todd Syssa's little gem appeared on the scene, just in the nick of time to spare me from going electric, as I was about to do.

Up until now, "pattern" and "economical" have been pretty much mutually exclusive terms, but now I have a very decent flying model that cost just a bit over $2k, along with a bit of experimentation and elbow grease. When one surveys current top-line offerings, $2k is indeed economical for a RTF model, and the low fuel and maintenance costs and engine reliability are some very nice icing on the cake.

This is one of the best things to happen to pattern in a long time because it may well re-invigorate pattern and bring in a lot of new faces. And after a lot more seasoned pattern guys see yours and Ed's and other Syssa-powered models fly in contests, a lot of them may change their minds about gasoline-powered pattern flying.

Thanks Bob,

The ZDZ40F3A isn't dead by any means. It will go into the EF Extra. The plane needs the extra nose weight. But that's a project for the fall. I have returned to my first plane on the drawing board and will try to finish it over the next few weeks.

Ed gave me an broken up Integral shell and I will try to piece that back together and make a mold from it. Always working on something lately...it's all good

Where can I find Ed Alts (IBE)?

Todd Syssa is selling the SAP IBECs. Ed doesn't have it posted in his website but I think Todd does on his. You can purchase one directly from Todd Syssa.

To Matt

I would like to say your ideas are great and everybody's that has contributed to this thread. But anybody that dissembles Todd's engine or any engine for that matter owen both halves and like I said earlier if some body wants to change the timing they should consult Todd first especially if you want him to help you when or if you have a problem This engine is one of the finest engines in the rc world today power to weight and reliability.

Gordon

PS. I have 2 of Todd's IBEC on 2 planes and thy work great.

I have been following this thread with great interest and appreciate all of the good work you guys have put into fine tuning the setup for this engine in a pattern plane. I have been flying an Oxalys 50 with a YS63 and would like to upgrade to a modern full size pattern plane with the SAP 180. What ARF is a good performer and would accept this engine and pipe?

Hmmmm!! There are a bunch of ARFs that you may use. Starting with the Focus that Bob Moulder, Dan (Gungadin), FlyEng, and some others are outfitting, this is a relatively inexpensive, great flying model. It will require some small changes to the tunnel to make the pipe fit but other than that, it should be straight forward. It requires some level of experience to fit a soft mount into the cowling too but Bob Moulder has a bunch of photos earlier in this thread showing exactly how he did it

There are much more expensive planes you could go with also such as the Prestige by WistModel, CARF Integral or Valiant, and pretty much any of the OXAI models (very expensive) can be used. There are also the CA Models Passport and ONAS and Visa. It really depends on your wallet size

I strongly recommend that you either have a soft mount made or build one yourself. I have written a tutorial on how to make these somewhere in these threads.

Glasairdriver, I don't think you will be disappointed with the choice of the Focus II as your first 2-meter pattern ship, both from the perspective of flying qualities (which are excellent!), and the "conventional" firewall/cowl configuration which give you a lot more working room when installing your first soft mounted gasser.

Matt, I just ordered my second SAP-180 to start assembling a back-up (or primary) plane. Don't know yet what it will be, but hoping that EF or 3DHS will get something to market in our lifetimes, or possibly pick up something second hand for a retrofit. I could happily repeat the Focus II exercise - and a lot quicker this time! - but I just want to try it with a widebody plane with a fully enclosed pipe and a chin cowl.

Bob
Now that you have a couple gallons of flying on the mount, how is it holding up? Make a really good inspection of the glue joints...push on the rubber to make sure it isn't coming off.

Great on the new engine...I'll tellya, I'm sold on it too. Now that we have some real time on it, it definitely has more pop than OS140 and Webra 145. I think it will fly about any 2 meter pattern plane we have on the market today and do any maneuver we want

Matt,

I was able to do a thorough check of the soft mount the other day when I was installing the nitrile tube (thanks![sm=thumbup.gif]) in the nose ring, and it was totally fine as far as I could tell.

I have no reservations at all about using the SAP-180 as the powerplant in my next pattern plane.

The extra 15.5x12W props arrived today from GravesRC, as well as an APC 16x12 pattern prop from Tower, and the Macs header for the next project.

I actually got out and played this morning since this weekend will probably be weathered out. I tried the mixed fuel experiment and all I can say is WOW!!! Very smooth running, and extremely cool (Temp wise). The cowling on Temptress is close fitting, closer than any of the fat fuses in vogue today, but still, after a run using the mixed fuel, the cylinder was barely warm to the touch.

It was a 60:40 mix of 87 NL Autogas and 100LL Avgas. Oil content is about 60:1 mix.

Turned the 17x12 only today. Never went to full throttle except on the ground to check it. In the air it's just too much speed and in windy weather it is probably useful. Today was maybe 5 to 10.

A bit quieter than the 18.1x10 as one would expect. You know, with this engine-pipe combination, it is hard to hear anything lower than 1/4 throttle in the air. Carb is pretty much set...my intent going forward is to use the mixed fuel. I really liked the table manners even more than usual and fuel smell (lack of) is hard to beat. Oh BTW- we fly at Solberg airport and wouldn't you know it, they are the lowest priced Avgas retailer around.....4.39$/gal