clivemc

DagTheElder

MTK,

I noticed your numbers re OS33.
A quick run thrugh of a 33ccm engine indicates this: Rev/min 8000, BMEP 10,00 bar, Piston speed 9,76m/s, ~~ = potential power 4.37 hp.
The BMEP is way into racing engines.

Regards

MTK

Clivemc,

You're welcome...

Running the Mintor 38 and OS33 side by side on the same props and gas, the OS turns the props stronger, better, at higher r's. I have about 1 gallon avgas through each engine so their break in is still ongoing. Could be that the Mintor needs lots more break in than the OS, not sure. The Mintor has its strong point too; it survived a head in crash into the ground from 300 feet with barely a few bent fins. The engine is made from machined billet afterall, and is likely to be much stronger than any casting. Heck my OS broke a backplate just sitting there it seemed.

An 8" pitch is not a match for any of these engines. My SAP 180HP, a 30cc engine, turned an Xoar 19x8 (piped set-up) at 8300 rpm. Too many r's and not enough thrust for pattern planes (Temptress). Loud also. It just wasn't very useful....I am also very cognizant of the fact that I am probably looking for something different from my set-ups than others are. My benchmark is the YS170 4 stroke's handling of something like a 19x11 or 12

The M38 may benefit from larger ports...I have discussed that before and at some point I may actually play with port opening a bit.

Pipe lengths, from plug to reflector baffle are the same for all 30cc class engines, 28". BTW the Mintor pipe is a very nice device, well engineered and lightweight and includes the header. At about 1/3 the cost of an ES carbon pipe for only a 1 ounce penalty, it is a bargain (assuming you buy the Hatori header which is quite pricy for what you get). Makes me wish that Karl Mueller was still making headers for this size engine.

MTK

We've been blessed with some pretty nice weather the past several weeks here in the Northeast. Have continued to fly the 33Gt and now have two gallons through it, some 30 flights. I think it is fully broken in finally. Still running the 19x11 and getting tremendous, quiet power out of it. A friend of mine has an 18x12 3 blader that will lend to me so we'll see how it runs on the set-up. Particularly interested in quietness and brakes

I will be installing the 33 in my new Aesthesis pattern plane this week. Really curious about how this combination will work

MTK

Aesthesis and OS 33GT are well matched.

The plane is heavier than I would like at 10# 14ozs, but the OS still flies this draggy model around at half throttle. Figured out how to put a nose ring around the sensor. Ground the sensor housing base about 1mm giving me about 2mm total clearance. That's enough to lay in the rubber ring. Forward engine movement still happens but snce much of the ring is rubber, it's not too much of an issue.

It was great to see Aesthesis take to the air with authority. The SAP180 didn't quite have enough beans and the Mintor 38 derfinitely did not.

MTK

BTW- for any one out there contemplating such a project or for any one using teflon couplers to couple their exhaust system and have not been happy with the leaks, here's an idea that might help.

You can build custom couplers as I have done. You can build in any sort of angle or diameter mismatch you may have. Here a how to:

Get a small quantity of ceramic cloth from any decent source. Mine was McMaster Carr. 6oz. glass will probably work too except go 3-4 layers. Cearamic is thick and fluffy
Get some Permatex Ultra Copper hi temp gasket maker for gasoline engines (also from McMaster, but there are many sources).
Set the header/canister/pipe pieces exactly the way you want them.
Line the attachment areas of the stems with plumber's teflon tape. The lining keeps the silicone from adhering to the aluminum
On some scrap plastic sheet rub the Permatex Ultra Copper into the ceramic cloth. You want enough cloth for two complete wraps. Wear gloves as this is a bit messy. I use a small seam roller for wallpaper
Lay the wet cloth over the header/canister stems and wrap the work with more plumbers tape making sure you pull everything tight. Let cure for a few hours or 24 for full cure
The teflon tape peels off easily leaving behind a very nice finish
Twist a bit to separate from the stems and voila!

If you want some exhaust stingers do it the same way except use so 2-3 oz glass cloth and rub the silicone into the weave as well as necessary to seal it. Wrap 2-3 layers over the size tube you want. Make sure to teflon line the tube mold first.

BTW- the DA flex header I used on my DLE55 eventually burned through the teflon tape that lined the flex area, after around 70 flights or so. Started to sound like a kazoo. The flex area was repaired the same way with one wrap ceramic cloth and Ultra Copper. Still going almost a year later.

choihjin

My Feedback: (1)

Dear MattK
It is very useful. I am going to tell my friend who is struggling to tight his E40 tube to Hatori header. Onece he tried to fit those with a silicone tube. The tube was not durable enough to withstand the hot and high pressure exhaust gas. Thanks for your sharing a great knowledge.
Also congratulate you on your successful F3A flight with OS GT33. Mine with GT 33 is also very powerful to pull a heavy airplane weighing slight more than 12 lbs. My custom-made composite plane is tail-heavy. I have no idea how to reduce my plane. But it is still powerful to pull straight up without any hesitation. Regards

MTK

Thank you....I will post a couple photos tonight as time permits. This technique is so simple and useful, I'm surprised no body has thought of it before. It is particularly well suited for our toy planes since we often has mismatched parts to fit together....

The OS 33GT has most of what we need for pattern. Terrific power at all throttle settings, ability to turn large props, and so on....
One thing that I've noticed now that I am no longer worried about the engine's abilities and I am paying more attention to the quality of the runs, is a very fine line at half throttle between rich running of the low end and clean running of the high end. It seems two or three clicks either way, going up or coming down on throttle, and the engine will go slightly fat or clean up. Spoke with a friend about that last night again and we think it is strictly the Walbro....

It isn't that much of a problem and is easily flown around. But we pattern people are always looking for the cleanest throttle curve we can find. It is precisely what drove the development of in-flight fuel mixture carbs for glow engines. An in-flight fuel mixture for the Walbro would probably eliminate that minor issue

MTK

Here are a few photos of the assembly. Teflon tape is slick and leaves a nice, clean finish on the silicone.

Note the thickness of the stinger tube......it is basically 3 layers of 2 oz cloth filled with Ultra Copper silicone seal, about .008" thick, weighs 2 1/2 grams. The key was wrapping the final assembly with teflon (thread tape) tightly enough to squeeze any excess out

MTK

The soft mount is extra thick and soft. The engine shake is considerable since this is a higher compression, stroked engine. Not quite the shake of a YS tho. . Still, the plane moves around at idle.

The last photo is of Aesthesis with the SAP180HP up front. Having a rear exhaust was definitely more convenient. Although the side exhaust return to center still fit inside the cavernous fuse

David Bathe

Matt, I think what been up to is very inspiring and wish you only success, just one question... that nose ring/assembly. Is it up to it?
What would it take to move the sensor/pick up to a different place?

MTK

Thank you David.

Moving the sensor is not a big deal. I've moved the sensor of the DLE55 so moving it for the OS is the same work. The broach is the same, 3mm. Just need to cut a new slot in the aluminum prop driver, and I may do that sometime in the future. For now, I intend to fly Aesthesis as much as practical, to learn it's character and figure out how to write good stuff with it.

The nose ring is pretty strong yet flexible. It is made of 1/32" aircraft ply laminated with glass cloth. The rubber ring that does the actual isolating is 1mm thick sheet stock from a motorcycle inner tube. Simply cleaned well and superglued to the lam-ply.

Here's what I do to laminate rubber and wood. First I clean the rubber of any anti-block coating with soap and water and then isopropyl alcohol. Then I use a Dremmel sanding drum to remove the sheen off the rubber and expose fresh rubber. Then thin ca is wicked into the assebly. Such bonds are very strong, rubber tearing

MTK

I consider the subject closed...The experiment has been successful. Time for other things

TimBle

should make this a sticky entitled, suitable gasoline engine for pattern

MTK

Hmmm! Don't know how to do that;

You may be right tho, especially for parts of the world other than US. In the US, EVERYBODY and his dawg have gone E-Power. I am the sole gasoline user here and only one of maybe 25 who still use wet power of any kind. E-Power has a couple benefits (and certain inconveniences) over anything available using wet fuels. Each fuel has its strong and weak points

The biggest benefit of gasoline in particular is the fact that cost per pattern schedule is miniscule. I have trully enjoyed the challenge of making such a set-up viable for pattern. It's been like being a kid on Christmas morning. I think there more to come too as I try to improve mid range response....

Freddy

My Feedback: (3)

Sorry Matt I know you are trying to close this thread but I finally scanned through the whole thing focusing on all your comments. Great job and kudos to you working through all the kinks with this new product! Your early frustrations (with OS support) showed but I am impressed by your persistance and knowledge and making it work. Your Aesthesis looks very nice.

FUEL:
I am still using wet fuel for pattern power and will only stop if there is no more fuel on the planet. I am environmentally very conscious though not to the minute scale that RC represents in the grand scheme of things. I have flown all the 4 strokes up to the YS160DZ so far and will be breaking in a brand new YS170DZ this spring.

Bpar4

My Feedback: (1)

MTK, Thank you for this wonderful thread. Your setup info with the problems encountered/solutions for both the plane and the OS motor has provided a pattern beginner with a nice guide for a high level pattern performance plane. Don't go away, "we" need more of this stuff. Bob

aerobear

My Feedback: (4)

Wait! What happened to the lightened 55? If you had a pattern plane optimized for the 33 and one optimized for the 55 which do you think would have the advantage? Could the 55 make weight? Have you decided that the 55 is not worth pursuing now that you have the 33 working well? Thanks.

MTK

Heavens, NO! Not going away, just that the OS experiment has reached a natural resting point. If I come up with anything new on that powerplant I will post.

BTW- I've just completed a 20x10 hybrid prop for the OS that should work well. I'll post photos soon. Yes I could just buy an APC. But the weight of 20x10 apc is over 5 1/2 ozs and that just leaves me shuddering. Also the weight of the 20x12 WPN is 7 ozs and 20x12 PN 6 1/2. My MDK Hybrid 20x10 weighs a scant 2.5 ozs. I am also looking at a 20x12 hybrid that should weigh less than 3 ozs.

In mean time, I have new plane design in the works and will start to concentrate more on that build. My Delta will be powered with the lightened DLE55 on pipe. You may follow along in the Derivative thread. I am in middle of developing a new way of glassing stabs and wings. I will be outlining that process there.

MTK

Still in the works....Not only worth pursuing, it will be an absolute electric killer. At the risk for jiving up hype, that set-up is the most impressive thing I've come up with yet, much more so than the OS33GT. Will it make weight? It will be very close. The plane is very large for a pattern plane....1180 square inches of wing area, 265 square inches of stab. It has all the advantage. I do not subscribe to the tinsey winsey wings many are doing in pattern nowawdays.....A pattern plane needs to fly on its wing as much as on its thrust

TimBle

agreed. Hence like planes like the Adrenaline or zaphira. The freeystyle type flying demands more wing area for all those slow manoeuvres.

MTK

Today was the first truly warm day we have had. Temps in mid to upper 70's. Still not summer but not cold either. The barrowed 19x11 went back to its owner and I flew with the 18x10 Mezjlik 3 blade. Needles actually needed a bit of leaning...a combination of warmer weather and lower load.

Anyway, on the third run it got a little stubborn so I used the damned meat grinder on it. The cone slipped causing the front end to shake violently, damaging the nose ring set-up. Aggravating since it ruined a perfectly good flying day. Damage was minimal and has been repaired...............

My Aesthesis is absolutely a dream to fly now. It has the right amount and kind of power to make for some outstanding flying. I can't wait until the next time I get to fly. Feel like a kid again......

NJRCFLYER2

My Feedback: (42)

I got a chance to fly Matt's Aesthesis yesterday, and itflies very well. I think I may have briefly flown it last year, before it had the OS 33GT in it, and before Matt had worked out the trim requirements. No comparison to how it is now! I went straight into the Master sequence and it was very comfortable, no issues, no limits.

Everything claimed about the power of the pipedOS 33GT is true. It has plenty of power for any 2M ship I can think of.The pipe setup wasn't peaky, actually fairly nice, and the sound level was very low with the 3 blade Mezjlik. Very nice combo!

cmoulder

Sounds as if Matt is close to finding his Holy Grail!

WOW, mega kudos, MTK![sm=thumbs_up.gif][sm=thumbs_up.gif]

MTK

Thanks guys!!

Tried the 20x10 MDK hybrid today. The hybrid is basically a 20x10 XOAR electric woodie laminated with carbon. Wood is recarved to fit my desired design parameters and and then laminated....

The engine hauled this prop around just as well as it had the 19x11 apc and loading the OS to about the same level or just a hair more. The wind was up, very bumpy and in my face this afternoon, the kind of wind which is most uncomfortable to fly in. Had to use a bit more throttle but still mostly at half throttle....Engine is continuing to impress