Good point! I forgot... Ed is using this model as his test bed/break-in for his SAP 180.

Better hurry! Alas, NE Aerodynamics is going out of business, and it looks as if they're taking remaining inventory to the WRAMS show.

BTW, Who's going to WRAMS?? I plan to make it there Saturday, also for the NSRCA meeting.

GHoffmann, this plane is definitely worth the (short) drive for you. As I recall they are located in Hollis.

John is a nice guy. I am sad to see suppliers like him going out of business. He had some very nice sport flyer kits, and really put a lot of effort into the Aquila specifically to cater to us pattern pilots.

I would also suggest the Focus II as it really is an excellent plane.

I don't know how much work would be required to "make weight" with either of these planes on the gas setup. It should be possible as the Syssa weighs only slightly more than a YS 4-stroke, but the actual flying weight should be lower based on the smaller fuel load when using a gasoline engine.

I called them this morning, left a message. I was planning on just driving over and seeing what he has left.

Nice piece of work.

May I ask what size of the rubber tube you guys purchased? I am considering build one for my ZDZ40.

thanks.

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I found that a 6"x6"x15" tube fit the disks perfectly. Just like cmoulder my disk were just under 4".</p>

If I get the chance this weekend, I'll bench run the Syssa on my mount. I'd like to run it to get the needles set and make the initial set up in the Focus a bit easier. I went ahead and bored through from the front of the mount so that the firewall screws could be installed from the front. A smart man pointed out that I would have basicaly no space behind the box mount and firewall. I hadn't thought that far ahead. Impossible to mount from behind unless you cut through the main firewall. This wasn't really a reasonable option. So now I have blind nuts in the mount box that allows mounting from the front. It will install very slick now. I installed the ball link on the throttle arm to the inside of the motor. This allows the throttle push rod to pass just to the inside of the mount so it will operate with zero binding and little effect from the engine rotating. (Not that it will rotate much.)</p>

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FlyEng, I think you will be very happy with the way your mount works. Your craftsmanship looks superb, and I am particularly interested to hear about the movement (or lack thereof!) in the spinner area. I think there will be very little if any, and I'm hoping that we won't need nose rings at all with these mounts.

Just remember, if you plan to run it with the pipe the needles need to be richened up a bit because fuel consumption goes up with the pipe. The factory settings are for the Pitts muffler, which are lean for the pipe. I had a bit of trouble with the first couple of starts until I richened it up. I don't remember how much (because I was kind of flailing around and didn't write anything down) but I'd guess about 1/3 turn for High and 1/4 turn Low and then work from there.

Guys,

The high speed should be around 2 turns open and the low around 1 1/2. This is a good place to start.

I am turning larger props than the typical pattern fare in mine so my needles are very slightly richer than these settings. Adjust once you get a feel of how the beastie runs with these needles

Matt

FWIW, I just checked mine (at last!) and they are H 2-1/4 turns and L 1-5/8 turns, and it is running and idling well with the 18x10PN, 87 octane w/Pennzoil 40:1.

Maybe a little rich, but not much. Can oil type/ratio affect this?

It potentially can but shouldn't be much. The oil content we use is from about 1% to 2 1/2%. Not a whole lot of difference there to make much of a difference. That;s my guess anyway. Ed has much much more experience with gas than me and he may have a little different take on it

Matt

Another factor I forgot to mention... I first tuned it with ambient air temperature of 10-12 degF, which means relatively dense air. Next time I flew it, it was about 35 degF.

I haven't flown or run the engine again since then... still holding at about 2/3 gallon of fuel through it thus far.

Come on, spring!

Matt,

Something else I did - which concerns the issue of erratic running/sagging when doing an outside loop - is to put a "static line" (if that is the right term) on the little ambient pressue plate (if THAT is the right term) to counter the pressure changes in the cowl that I suspect cause the erratic running. This worked before when similar issues were encountered with aerobatic models.

Depending on conditions tomorrow, if it isn't too windy and one of the fields where I fly is clear of snow, I will try to get in some more flights. At the very least I'll run the engine some more.

My soldering isn't the best (use one of those little butane torches from Radio Shack) but it is solid and clean.

Also I noticed that the header bolts were loosening up, so I drilled through the bolt heads and made a little "clip" from 5/64" piano. Don't know if this will work either, but it's winter and I am trying to do this since I'm not flying much!

Testing. My first response went no where

OKAY THEN!!! That time it worked

Bob,

I've read the static line help before from Don Lowe if I recall. It apparently helped one of his set-ups. If I remember correctly, it settles down the reference pressure that the pump "sees". It allows for steadier pumping I think, but I am not certain and I am not an expert in gasoline engine function. It shouldn't hurt anything and I may do this some time too.

In the limited flying runs I've made, i haven't noticed erratic running on outsides in the test bed but that may be due to lack of flights.

I know my field is still snowed in but possibly with temps in the 40's today, we can get most of that to disappear. I am sure the CA and FLA crowd is laughing at our snowed in woes. I know I did when I lived in FLA (BG). Tables have turned.

Anyway, planning to do some bench running today on the 18x12. Here're a couple photos

And one more; this one shows the stock wood tip and the modified, carbon covered tip. Having that much area at the tips loads the engine down unnecessarily. Much of the work is lost to tip vortex (drag) and noise

DAMN! That is a nice looking prop Matt!

I hope you described how you did that somewhere

Thanks Chad,

I am preparing an article for MA on how I do it. Of course it isn't the only way to do the carbon cladding but it's the way that works for me the best. I don't have the verbiage written fully yet but do have the photos. PM me if interested

MattK

Georgeous craftsmanship!

My first one isn't going to look like that, I'm sure.

Thank you Bob,

Guys,

The 18x12 prop was run this afternoon and all I can say is wow!! This will be the prop I want to use on the SAP 180...need to get some flying time on it.

I couldn't get rpm but maybe, if Ed is up to it after the WRAMS, we can get some numbers. The engine was very happy running this one probably around 7.8-8K (by ear) on the bench. I did notice a little jump at about 1/3 throttle.

Hey Bob, BTW, I used the technique you had suggested with the Tee in the line...works great. No more problem with fuel draw. On the bench it's easy to see how the rocking motion between TDC and BDC works to draw fuel. It definitely works better than bringing the prop through, Todd was right

I cut the 18 5/8X13 down to 17 3/4 x13, by trimming the tips only. The engine turned this prop much better than before. 13" pitch is possibly a bit much but after full break in, it just might work great too. I'd place the rpm at around mid 7s but it still had some uncertainty and a little fluctuation probably getting a bit hot. Not quite ready for prime time.

Fruitful afternoon overall.

Matt

Sounds like you're really zoning in on the sweet spot, Matt!

Once I get mine a bit more broken in I will start swapping out that 18x10PN, maybe compare some numbers with the APC 18.1x12PN and your hybrid, after I concentrate on getting properly leaned out. Still a bit rich, and no reason to leave it that way with a gas engine.

I got a box of the 1.5-oz packets Amsoil Saber for the 85:1 mix.

Bob,

Neither did my first one. The prop in the photo has an epoxy paint clear coat on it. A little polishing (Finnesse It) and that's the end result. Final weight is 52.5 grams

Matt

PS- this photo shows how thin the tips really are and the fact that the hybrid's tips have been de-pitched

Whoa!!

Can't wait to hear what you Masters-level guys learn from actually flying it!

the hybrid's tips have been de-pitched


DULY NOTED. Another important refinement in the overall re-working.

My afternoon was fruitful yesterday, although I got zero prop data.

What I did learn is that a tuned pipe "reacts" very strongly to being 3/8" shorter on the baffle distance!

RPM figures were waaaaayyy down and the needles were not happy. I thought it was caused by my static line modification, so I took the line off and it made no difference. Thought maybe the H needle was perhaps moving around on its own. Nope. Only later did I notice that my Velcro pipe strap had slipped off the back of the silicone insulator on the back of the pipe, then I put 2 and 2 together and realized the coupler distance was incorrect. Gotta re-do that to the magic number: 27-1/4" plug to baffle.

Good news is, the coupler held tight and didn't leak one molecule, and the header held firm and was not bumping anything in the forward pipe tunnel. Ran very quietly, but then the RPM with the 18.1x12 was ony 6300 because of the pipe issue.

Bob,

Are you saying that somehow your pipe was shortened 3/8", plug to baffle?

When the load is too large for the engine, what you describe is how the engine will react, all else being equal. When I was playing around with the 19x13 stock prop, I could only get around 6K, but the 18,1x10 would turn its normal rpm of around 7800 to 8000 on the ground. The 18.1 x 12 may be too much load. Blade shape has a lot to do with how the engine reacts

You are right, we don't want to run shorter than 27 1/8" plug to baffle. Longer is okay (don't know yet how much longer is tolerable).

I need to figure out what the slight jumpiness at 1/3 throttle is and how to modify it, to smoothen it out. I suspect that running the pipe a little longer will eliminate that, but will probably drop the high end rpm slightly also. A slight drop, say 100 rpm or so, is not a problem. Ed Skorepa may also shed some light on this.

Matt, yes, when I re-taped it I made the coupler too short. I measured it at home and it was about 26-7/8". It doesn't like 26-7/8" at all.

In that case, I may try 27-1/4".

Out of town for work this week. Won't be able to get back to it again until next Monday, if then. Having some remodeling done in the house after that as well, so it will have to take a back burner for a while.

I ran some more bench tests using the 18x12, trying to remove the slight jumpiness at 1/3 throttle. Also managed to take rpm readings.

Determined that the low needle was slightly rich. Leaned it about 1/16 turn and now the LOW needle is just under 1 1/2 turns open. The HI needle was not touched and still is at 2 1/8-2 3/16 open. Stretched the pipe by 3/8" and that, combined with leaner low end, eliminated the jumpiness at 1/3 throttle.

Making the pipe length measurement more convenient for myself, the distance from the plug CL to the end of the pipe (not including the stinger) is 33 1/2" straight line. That's approximately 27 1/2" plug to baffle.

Top end rpm is higher than my ear perceived originally...I tached it at 8200 after the changes. Pretty terrific!! Throttle response is now about as linear as anything I've played with before and with the amount of output available from this powerplant, the 10 pound Aesthesis will fly in style.

Can't hardly wait for spring....back to shoveling snow...sigh!!

Matt