arobatx

I'm looking for feedback from those that have tried getting the very most out of this engine, balancing power and load, with a prop that takes advantage of it at the appropriate RPM. I'm hoping someone has tested with something other than the typical aftermarket in cowl exhaust, perhaps a two-into-one header, with single cannister...or similar. I'm curious how much thrust can be made with such a setup, on say a Mejzlik 24x10. Seems with a very good exhaust, the torque is going to drop off in the mid 7's...but I'd like to hear from those who have gotten all they can out of this engine with good prop and exhaust choices.

Toni Clark is a good source, and I've inquired with them as well for additional data they can share from things they've tried. Racing would not be my goal here at all...though I am very interested in anything Ralph has to share on this, as he's surely got some good experience to share as well.

buck1856

My Feedback: (49)

I would be interested as well.I purchased a used GT80 a while back and removed the stock ign,with the spring start.I have a ch im going to install along with a set of bud bolle mufflers.I bought a set of headers off of a 3W engine i believe and only have to modify the exhaust flange holes a little.Im going to call Ralph and see what prop he recomends for this unless he jumps in here.Or somone else does.Its going in a 31% Lanier Staudacher,9WS.Plane weighs 12 lbs right now,all framed up,with cowl and landing gear,wing tube[aluminum],and canopy.Im not worried about 3D at this point as this is my first Giant scale plane[roughly].Im going to start out in basic IMAC.

arobatx

If you aren't racing....run a very good wood, or carbon 24x10. If your exhaust system is tuned, and very good, i hear you could run a carbon 24x12 pending the design, but I am waiting on a report from Gerhard at toni clark for more info on that.

arobatx

Well, the only response I've gotten is from Gerhard Reinsch, they've got a two-into-one header, into a nice KS cannister, setup on a scale biplane, spinning a 26x8 Menz S at 6400rpm, which is fantastic on the 29lb biplane they are flying with it. They've got another one setup with the same header and cannister on a 2.5m Extra, spinning an Engel Super Silence carbon 24x12 at 6900rpm...certainly respectable!!! I've never heard of these props on this side of the pond, but I would be interested in hearing how they compare to a Mejzlik Thin in respect to load and efficiency. I've inquired about a static thrust reading from Gerhard for that prop/rpm and will post it here...

arobatx

Hey Buck, since you spoke up, have you completed the conversion to EI yet with CH parts? I'm curious how much weight you took off with the old ignition components, and what the weight is with all EI components now. I'll throw in a few ounces for ignition battery....

pe reivers

The Engel props are toothpics with very narrow blades. They impose buit little load on the engine, and are very quiet, which is important if your club has noise limits. (most clubs in Europe have!). Like the APC-N type, their thrust is a bit disappointing, but with noise rules, rather fly, than not fly at all.
All in all, The Mejzlik and 3W carbon props give better overall performance. On 80cc, a mejzlik 24x10x3 would rev up nicely. Zenoah has a high rpm hotspot and likes to spin up though, so this prop may be a bit too large.
Maybe someone with experience with the engine can chime in. I may be wrong about the best rpm for the 80. With these size props, rpm should be kept below 6500.

arobatx

Thanks Pe, Gerhard did say they were very thin props...

buck1856

My Feedback: (49)

As of right now,with just the stock engine,no exhaust,with the ch ign,and with the stock flywheel.This is the stock flywheel with the 3 magnets.Ralph said i could do it this way and not use a new hub.One of the magnets will fire the ign.I think all i need is the adaptor that bolts on to the 2 lugs on the intake manifold from ch.Actually,i have one for a G-62 that i could copy or ill see if ralph can make me one or ill make one myself.So,it weighs 6 lbs right now.
As for what i took off,the ign parts including the spring and torrington bearing weigh 1lb-2-3ozs.
The stock mufflers weigh1lb-4-0zs.
The headers and bud bottle mufflers weigh140zs but that doesnt include the silicone connectors.Im going to call Ralph and see what he thinks.
He did say when i use the stock flywheel instead of a new aluminum one with a magnet in it it wouldnt save enough weight to bother with it.

arobatx

For me, this is just one of those cases where by the time I modify the engine, and get the exhaust on it that WILL make it do what I want, I will have added enough weight and money back into the mix, that going with more displacement will make more sense....something just makes me return to the 80, wanting to make it work. Someday the right project will come up!

Also, I need to clarify a mistake I made in my comments regarding the feedback I got from Gerhard at toni clark. I misunderstood and thought our conversation was about the 80 with their Y-header and cannister, when really the feedback was with their in cowl cannister for the 80, which as I understand it, produces about 20% less power than the Y-header and cannister will. An error on the low side of power is nice for a change, and boasts the capabilities of the 80 even moreso.

Thanks to all who replied, and Gerhard, if you happen to be reading, I am always really impressed with how helpful you are whenever I have contacted you folks with questions. I really appreciate it!

pe reivers

did Gerhard tell you anything about thrust yet?

arobatx

I inquired, but he didn't have anything to offer in regards to thrust.

buck1856

My Feedback: (49)

I talked to ralpf and he said anything in the 24x8 range to let the engine run up.He said it likes high rpms.He said an MSC would load it down a little much but the CF,zoars,props shaped like the BMEs,3Ws,DA,ect should be fine.I guess he also means the Menz,mezlek,ect that he likes.
These props are for Imac,sport flying,ect...