When was the LAST time there was a rule change for WS or weight of the aircraft??

Kochj,

When the largest engines allowed were 2C 60, they were run on alcohol. Figure out the cost of the average 60 2C airplane (then or now).

When 120 4C was allowed in pattern, they were run on alcohol. Figure out the cost of the average 120 4C airplane (then or now...it is more than the 60 2C).

When unlimited engines were allowed in pattern, they were (and still are) run on alcohol. And the average cost increased again.

IF you allowed 80-86" planes in pattern, some would use gasoline engines to save fuel costs. The best performance would be from 50cc engines running on alcohol (not unlike TOC competitors in the early days of the TOC). The alcohol powered 50 cc 80-86" pattern plane would cost a LOT more than the current 2M pattern planes or current day 50cc gasoline aerobats. Both the current day 2M planes and current day 80-86" aerobats would be at a severe performance disadvantage compared to an 80-86" purpose build pattern plane (running on alcohol).

Regards,

Dave

Thank you for the info about the internals, I wouldn't go with a DL anyway..but wanted to know if there
was any performance difference...

How did you fair with the lightened zdz40cc??

5kg or 11lb has been in place for a very long time....was never a consideration until the engine displacement rules increased.

I want to say the 2M limit went into place in late 1980s (when the 120 4C was allowed), but maybe it wasn't until the early 1990s.

Regards,

Dave

Larger engines certainly contributed to the increased price of the engines, and perhaps Japanes wage increases contributed as well. No matter, the larger planes, servos, etc still cost more money in addition to the more costly engines.

Regards,

Dave

deleted...double post

Wooa there guy....I think that YS makes exactly that. The engine has many positive attributes for pattern and everything else except maybe racing. It also has several nagatives, as is true with practically everything. Most people involved deeply in Pattern know these pros and cons and the ones that go the route of the YS are willing to accept the cons

The point Ed and I are driving to is not that the Syssa 180 will compete with the YS170...it can't at it's current state of development. The point is that for many applications (and you could argue that for as many as 80% probably) the Syssa is a pretty good alternative to glow 2 strokes and all other 4 strokes, and probably electric (much less costly).

Of all of these alternatives available, electric is perhaps the most versatile...the trade off is cost which is coming down a bit as batteries improve. Again, the point really is it's a good alternative

As far flying lightly, most pattern people don't know what a 50 cc class IMAC plane flies like and don't care. Ed and I do. Ed still flies large IMAC planes since he came from IMAC. If you ever flew a 2 meter thoroughbred, you wouldn't be making such comments

MattK

I have the engine and like it. It's heavier than I wanted for my experiments. Sure my model will make weight with the ZDZ40 but nobody else's will. That 12-14 oz penalty is too much for most to overcome.

I decided to use the Syssa in the new design. Model will weigh around 10 lbs...very sporty

MattK

Matt, as I've said before this is very interesting, and having campaigned with the MVVS 160 this far and away a better more powerful setup. the MVVS would be lucky to turn a 17x10N at 9000 and not blow bottom end bearings every 40 flights.


I do have a question though. do you think there's provision for extending the prop shaft away from the cylinder some more (thrust washer extension or somesuch). The one thing that I've found hard to do in most circles is hide the biggger head and spark plug cap into a nice cowl. If I could move the engine aft I'm sure it'd open up a few more possibilities in the "sleek" department.

I am betting for Mintor 37cc and their extreme light pipes if I am going to change my MVVS to another gasser. Mintor have so much more punch than Syssa or MVVS.

Well I haven't had any bearing problems with MVVS and I am using 16x12 APC.

I'm not going by manufacturers claims but by rpm levels with the same Vess 18X6 prop. The Dle 30 (new engine) spins one at 9000 and the Syssa is reported to spin one between 8100 w/inserts http://www.rcuniverse.com/forum/m_88...48/key_/tm.htm (Post #1184), http://www.rcuniverse.com/forum/m_88...40/key_/tm.htm (post #978) and 8400 http://www.rcuniverse.com/forum/m_88...39/key_/tm.htm without inserts (Post #964).

I was being kind saying the DLE is only 1/2hp stronger.

On post 37 here, the Syssa is turning an 18X6 Vess at 9300, which to me would indicate the Syssa is stronger. I can't believe a pipe would make a 1200 RPM difference.

Arch

rcpattern,

Ya, and I can't believe it's not butter

Depending on the porting and the length of the tuned system, even greater rpm gains could be achieved. Some engines respond dramatically to a pipe and some don't do to the porting.

I am posting the finding of engine owners, not speculating.

In Todd's engine manual with the engine running without exhaust restrictors the max rpm is rated @ 8750 rpm with the Vess 18X6. No one running the Syssa has acheived that rpm with the stock exhaust, yet.

As previously noted in this thread.....how fast an 18x6 will spin is pretty meaningless for pattern applications....not enough pitch to be useful. Static RPM of 9300 is also pretty meaningless for pattern since the noise is going to be pretty loud - certainly over 96 db (AMA) or 94 db (FAI).

And as most people learned who ran piped 2C setups in pattern, comparing ground RPM is of little use. Far more important is how well the engine "behaves" - how it transitions on/off the pipe, and how much power it makes it the air when the pipe is set for smooth throttle response. Best example of this was/is the Webra 160 MC, which when setup "best" for pattern often turned fewer RPM on the ground than a Webra 145.

Matt and Ed both have plenty of experience with piped 2Cs....so I am sure the setups they settle on will be flyable for pattern, and not just static numbers.

Regards,

Dave

Archie,

Todd Syssa was visibly excited over the boost he saw. He explained that his "normal" engine would turn the Vess 18x6 at around 8300-8400 on standard muffler without the stinger muffling inserts.

The engine was obviously very happy turning the 9400 on the pipe. Keep in mind that his exhaust timing is very long therefore the engine will tend to take advantage of light loads and spool up. Timing of our more typical glow 2 strokes in much more conservative, designed to allow more load at lower rpm.

An 18x6 is of little use to us in Pattern as Ed and Dave have mentioned several times.

To me, the proof came when we ran the 18.1x10 on my test bed. This model was around 11# 11 ozs as flown and is larger than most pattern models we fly today carrying over 1150 square inches of wing. Ed did a vertical rolling check to over 1000 feet and it still had plenty of beans.... we can't fly over this height at our field so it was cut short. This is a new engine afterall so that's why we have been excited about the prospect. After full break in, we expect better output

Matt

What is possible to make a two-stroker to do?
A two stroke racing engine 125cc may develop 85-90 hp @ 11500rpm. If we can translate this pr cc to an aero engine of 30cc there should be more than useful power available. Of course such an engie will not be everybodys favorit. The engine will be re-ported, re-designed cyl top and matching tuned pipe to send a plugging pulse back to the sylinder for max trapping of fuel and air. Such engine will probably have a BMEP of 11bar.
To increase a standard engine BMEP from about 4-6 bar to about 8 bar an increase in hp may be expected to around 0,8 hp and more from 4 bar. This increase will probably make such engine more difficult to use and may not be everybodys favorit, all depending on porting, pipe design and cyl top design.

AND

Such engine will be hellish noisy. I would not be surprised that one will be well over 100+dbA or more.

Regards

Matt,

The reason I posted the 18X6 numbers is because that was the info I had for both engines. Putting the DLE on the same pipe with the same pattern props would be a fair test. A wrap around header will make for a shorter tunnel length and the side mounted carb might be ok on the wide body planes.

I had recommended and hoped Todd would have set up the timing on his engine closer to that of the OS160FX, which is very conservative. One reason it's so easy on fuel in relation to the power output.

So run a DLE then!

My YS160 used to turn the 17x12 at 8200RPM the same RPM the OS160 was making on a friend of mine airplane, but the OS even dough had the same top RPM it had probably 40%less power from idle to about 80% power, of course he bought my engine and dumped the OS, so this is about torque not just top RPM.

Pattern planes flying with OS and engines alike are usually handled like an on/off switch it will not pull a solid vertical unless they are at full power.

So the Syssa might have more torque, and making comparisons at top RPM with other engines are not fair, I think this engine will be better than the currently available gassers as it's being modified with pattern flying in mind.

Kema, I was told by Pe Revier, that the problem I was experiencing was due to an overloaded crank, putting undue pressure on the bottom end needle roller, which in turn would distort the cage and then at a given moment, catch on the backplate when the cage split.

I have done a LOT of flying with MVVS, and now know what to look for. I was told that after 20 hours of use, the roller has a 10% chance of failure, I just made it worse with a bigger prop. After I did this a few times, I swapped to a 16x12, popped a head shim in and the problem seems to have abated.

I should point out that MVVS are aware of the problem and the subsequent version II motor has a bigger crankcase to allow for a bigger needle roller.

IF you have a version 2 motor (slant plug) then you're laughing, if you have the V1 motor (top plug) then just for your own peace of mind, pop the backplate off and take a look, if you see a distorted or belled out cage (get out the magnifying glass and check for cracks, it's time to replace the conrod.

I have both on order. I will run both and see for myself which one is the overall winner for me.

It will be interesting to see how many hours the Syssa can run under Pattern conditions without overhaul compared to another engine with similar output.

The Syssa is timed for higher rpm not low rpm torque. Field use will tell how good the engine is for pattern. It may be excellent.

.

Have no present intention of modifying my engine. If we decide to make changes later, I will probably discuss it here.

It occurred to me that one of the best 2 stroke engines for all around handling ease was the older style YS60 so called short stroke (the 61 long stroke came a couple years after and never ran as sweet for me). We simply stretched the pipe and ran big loads

The Syssa 180 is reminiscent of that experience...but enough hyperbole. I need to generate numbers

MattK

More flights soon with the Enigma?

If the Vanquish will be delayed (and EF isn't giving any hints as to how long!), do you have any suggestions for another wood airframe suitable for this engine? I realize that is probably bass-ackwards reasoning, but it is a gasser after all.