MTK

Mike,

Curious about the muffler or pipe you will use. Do you know if it was a muffler for the YS 4 strokes or is it an actual tuned pipe? If it is a muffler, I don't think you will get much boost.

The 18.1x10 apc is no real load for this engine. It's good enough to try a flight or two and it will not cause any damage or anything like that. But to get into the engine's power band, I suggest more load.

Interestingly, running a lower load doesn't mean gobs of rpm. You will get a false indication. I've tried it before so I know how it behaves.

Mike I've used from 1800 to 2200 ma batteries with the IBEC driving the CDI, and get 75 minutes comfortable flying time. A 2600 ma will buy you more flight time.

Love to hear how your early flights go. If it's like my first few, the smile was ear to ear

maustin

My Feedback: (7)

Matt, I do gave a APC 19x11 avail. Sounds like that might be a better choice pending getting the APC 20.5 x 10. The pipe is a ES Composites tuned pipe bought from Central years ago. I'll know soon after takeoff I guess LOL.

Mike

MTK

Mike, did you fly it yet? The 19x11 was my early break-in prop. Then an 18x10 3 blader from Mejlik. I expected more quietness from the 3 blader but that was not the case. Too many Rs; not enough load. After a few flights I moved straight to the 20x10.5 PN and broke the engine fully on that prop. I've used the same prop ever since and the 33 just loves it. Its a great combo.

I've played with the 20.5x10 PN also and the engine likes that prop too. Very good power and great brakes in cooler weather. It is an increased load tho and in very hot conditions performance isn't as good as with the 20x10.5 up front. I've settled on the 20x10.5 for this engine for all around performance in all conditions.

Now IF I ever get off my duff and make a mold of it, I should remove half the weight casting it in carbon.

maustin

My Feedback: (7)

On vacation this week. Will be ready as soon as we get back. I'll get the 20x10.5 prop. Haven't ordered yet.. Thanks

Mike

STEVE HOSNER

Have a great vacation Mike! Let me know when you are back in town.

Steve

flyva

Getting ready to place an order with McMaster-Carr and thought I would make some couplers. Would you be so kind to identify the exact material you use. I think it is from this page http://www.mcmaster.com/#silica-cloth/=s6dgmz

Thanks and good flying!

MTK

NO! that silica doesn't work well. Try this 88175K36. I use the 1" size; it's a braid so it moves to the size you want

maustin

My Feedback: (7)

First Flight Report: Ok got in 4 flights today and first impressions are this is an awesome motor and when fully broken in it will be a good alternative for pattern flyers to consider. Temps ranged from 90 - 100 over the flying session. The motor never seemed to run hot but I did have 2 dead sticks from probably being too rich. I kept leaning the low and top end until flight #4 flew the entire tank. Used a APC 19x11 and like mentioned in earlier posts this motor wants a load on it. I'll switch to my APC 20 x 10.5 next week, Starts were hand flip after around 5-7 choke cranks. It surprised some pattern guys that I was flying with on how quiet this setup is. Top ground RPM on flight 1 was around 6450 but on #4 I could hear the revs increasing. Now to just fly the dog meat out of it and play with the throttle curve. Happy camper so far.

Mike

MTK

Excellent!....There is a learning curve of course. Gas engines do not need the typical glow style break in. I just tune to max rpm, back off a 100 or so rpm, and just fly it in.That holds well for any given prop after break in is done. It may need slight tweeking, maybe a screwdriver blade width either way, but that's about it.

One of the better surprises will come during the off season. No maintenance required. BTW- if run rich, carbon builds up in a season inside the head. No biggie, easy to clean. If run on the sweet range, carbon build up is minimal.

After a couple gallons, take the plug off and check for mixture. If lean, the electrode will be grayish white; if rich, it will be wet and black. Just right, it is dry and brownish-amber. You will know right away when the LS needle is lean since the engine won't transition and die.Lean HS needle causes the engine to sag on verticals. And remember there is always needle interaction, the LS will affect the HS but usually not the other way around.

Good luck Mike. Oh yeah, the 19x11 will turn around 7600 on the pipe with the proper mixture. It's a good break in prop for a gallon or so, then load it down.

maustin

My Feedback: (7)

Matt, I'm learning this gas stuff. I studied up on this tuning after the weekend and yes it's diff than glow. I'll retune this weekend the correct way. Your RPM numbers indicate maybe I don't have a true tuned pipe as I'm not getting anywhere close to your numbers. I'll tach again this weekend and see what's up. Thanks for your advise and help in this project. It's been fun stepping out of the box. LOL

Mike

maustin

My Feedback: (7)

Hi again Matt, I found the model # of my old pipe I used on my YS 160. It's a ESD4c160C7. 5/8" inlet. 1.5" dia. Sounds like this might be the issue with not getting the RPM's you posted. Motor seems to not unload like I expected. Might be time for a pipe upgrade!!

Mike

MTK

Mike,

Your assessment seems right. ES makes the 35G for the 30c-40cc class engines. It's pricy but worth the money in weight savings alone (about 3 1/2 ounces). The inlet to the baffle distance is about 17" so judge accordingly.

Nevertheless, the muffler performance wasn't too bad. Seems to be on par with the regular muffler OS provides. The pipe gives you both rpm and torque boost BTW.

Actually it would be an interesting comparison after you use the pipe. I have never used the muffler so I'm missing that piece of info. Please keep me posted

MTK

Just this past weekend I had the opportunity to witness a fellow club member fly his OS GT33 powered EF 78" Extra on muffler. His was turning an 18x10 wood prop (didn't get the make) at about 6600 rpm. It was a new set-up and wasn't fully tuned but I seriously doubt he would get more than another 100-200 rpm out of the muffled engine.

The OS33 will turn the same prop at +1000 rpm if it were piped.

maustin

My Feedback: (7)

Matt, Took the motor out of the plane and back to the test stand for some tuning. Moved the pipe in 2" and whala the motor came alive. APC 19-11 was turning pretty consistent 7K. Smooth transition and great idle. Still not broke in but now I think we're getting up where needed on RPM. It's 10:30am and right at 100 degrees so I'm done for the day LOL.

Mike

tele1974

Quiet in here...something replace the GT33?

MTK

Heavens NO! It is still the best power plant for this sort of thing. The quiet has been me being unable to do much the past summer. Health issues. I assume Mike Austin has goTTEn A pipe on his and is having fun...
Have had an opportunity to see the DA35 in action and I was not terribly impressed. It should do better on a ESC pipe tho.

OS has done a great job stroking this engine. It s exactly what was needed to haul the big lumber. But frankly, the engine came out too late. Had it come out when the 140RX did, it probably would have dominated pattern for many years...

dingo9882

Quick question guys. Are you making the sound requirments with these gas engines? If you are how are you doing this because this would be amazing for me to get back into pattern with by putting in a gas engine.

MTK

Take a look at this Utube video. https://www.youtube.com/watch?v=iAd8dRxtNbQ. It's my Aesthesis/OS33GT/ESComposites pipe combination. The soft mount is my own design but Merle Hyde will make these also. The header is Hatori 2301 for the DLE30, OS33 etc. The prop in the video is the apc 20x10.5, which is readily available.

My best prop to date is a 20.25 x 12 wood-carbon hybrid of my own design...similar pull to the apc at slightly quieter footprint. It represents just about the limit on load.

We measured noise at 10 feet and got about 91 dB on the 20x10.5. In the air, well, you can judge for yourself....quiter than some electric geared motors.

maustin

My Feedback: (7)

Haven't been flying too much lately due to the heat and busy weekends helping my wife due to a broken foot. Same basic setup as Matt's but haven't sprang for the ES Composites pipe yet. I think our setups are more quiet than a YS especially in the air. Like Matt said almost as quiet as some electrics at full power. Most club flyers think it's a glow setup and are surprised when I tell them it's a gasser on pipe, Soft mount is the only way to go !!

Mike

drac1

My Feedback: (4)

YS's are quieter than some electrics.

MTK

We will have some interesting stuff to discuss soon in regard to powerplants (non electric). Looking forward to new developments and comparisons.

Champ-RCU

My Feedback: (132)

deleted

MTK

Well, Spring is just about here but the powerplant I was supposed to test against has not materialized.

That's OK, we have a new approach we will be trying soon. OS has released the G5 glow plug intended for gasoline use in their GG15 (90 sized) engine.

There is some work being done already on the GT33 with this new glow plug, converting it to a GG33 I suppose. I have decided to buy a couple glow plugs for trials so I'll see for myself how this new plug works in a piped set-up hauling the large props I'm using on the 33.

The weight savings is about 5 ounces since the CDI, spark plug and IBEC will not be used. I never did use an ignition battery and switch so I can't claim any of that potential weight savings (which can be 5 ounces or more). The new glow plug appears to be sized the same as any other from OS and is lit the same as old times. I Have come full circle.

flywilly

My Feedback: (121)

I'm really interested in the results of the 'new' gas glow-plug. If the ignition system can be eliminated then I'll be convinced to give gas a try. Without an ignition system there will be no 'kill' switch. Given the carburetion of a gas engine will low idle kill the engine?

MTK

Will,
In my set-ups the GT33 with CDI will die on the lowest idle setting so that should be ok. Just set it up so it will. If you ever get into gasoline, I sell a terrific gas line and nylon fittings to make your own custom tanks. Stays flexible for years unlike the yellow tygon. Inexpensive, about 1/5th the cost of viton with virtually no practical difference in performance.

I admit that Ed's IBEC was such a pleasure to deal with arming and disarming the CDI from a distance. The safety aspects are great.

I have the GG15 coming soon. They are still not in the US. Will go into my grandson's T-Clips. I 'll get first hand experience with the glow gasoline arrangement very soon