stol1

As previously posted, I think your expectations for an EA81 are too high, both in weight reduction and power output. I personally prefer a bit more weight and a bit less power for the sake of reliability. This formula has worked well for the 12 years and 750+ hours I have been flying behind my EA81. (This is my conversion, not a commercial

Can you send me some pictures of your installation? What did you do to your engine. I plan on doing my conversion, any suggestions would be appreciated. Thanks

Gooday Steve,After much headscratching, I chose to use a Foxcon redrive, as used on the Terrier 200. E-mail Foxcon direct for current price, as it has probably changed since I bought mine. I also used their prop hub and spinner, with blades from Bolly. Now has 68 hours flying on it and has been trouble-free (and incredibly smooooth!). The weight of my EA81, including redrive, starter, alternator, engine mount brackets, manifold, carby and oil (As weighed to calculate Weight and Balance for engine truss design) is 92 Kilos.

To this must be added the muffler (My own home-brew one weighs 2.5 Kg) and the radiator, coolant and hoses. I guess about 100 Kg all up

 

Hope this helps

 

John B

I am building a zenith 701, and have (4) ea-81 motors at my disposal, one with a rfi belt re-drive, and a fresh build on the motor. If I run this engine, it will have a spg re-drive, 24 lbs, less starter, a custom flywheel, 8 lbs or less, a carbon fiber intake, with a aeroinjector, maybe a aluminum oil pan, and aluminum pulleys, and a 20 amp permanent magnet generator.3 lbs . I will also be using aeromomentum's radiator, and am undecided about the prop. I have looked at exhaust but am also unsure there. A cam re-grind, and head work, hopefully will put me at 100 horses. If I go this route, I hope to see weights in the 170 pounds even if I have to cut off unneeded bosses on the motor. What are your ideas/ suggestions?

 

 

Interesting information but I will continue on my build till I am just about finished, then make the decision. If I had to decide now, I would lighten the ea81 with custom built parts, an swing a 70-72 inch prop with spg3 re drive, ratio being 2.34/ 1. I think I can get the weight down in the 170 pound range. After a cam re-grind, and head work, it should be around 100 horses. Just extra build time.

 

 

Does anyone know how to take the weight off the ea-81? I recently had someone say that one guy had it down to 165lbs with the 40 lb re-drive on it. That would be in the rotax range.

 

 

Although the OP is 12 years ago I'll add to the discussionMy 701 was built in 2003 and the engine I wanted to try was Diamond AE110R (ex Midwest Rotary ex Norton design) This engine never made it to production so I chose the Jabiru 2200. Other posibilities were Hirth 3701,, Konig MZ301i, Simonini Victor2, Rotax 618 or 582 or 912. Note that for my build of the 701 modifications are required to the rudder / tail attachments to use the 912S)

There has been a 701 in NZ built with HKS, changed to Corvair, changed to J2200. I wrote the owner who said the Corvair was great power but too heavy and thirsty rendering it a 1 seater for any distance

 

Another started with BMW, then Rotax 532, then EA81. I rode in the 532 version and it performed well. The 701 design started with 503

 

One has an EA81 with weights in the tail and reportedly didnt handle that well according to newsgroup questions from the owner

 

Another has a geared VW which overheated but believed to be still flying on the rebuild

 

One had a Simonini which didnt stay on long, believed to be 912 now, as are the rest of the 20 or so fleet.

 

All the 2 strokes have a poor reputation in NZ the 582 being the best prospect with a 300hr TBO - most do well over 600 without trouble.

 

Today we have some other choices

 

I have considered the 3rd,.or.4th generation 2200's, and may still choose.it. What would be your recommendations?

 

 

I have the same problem with choosing an engine. Here in the states, there is a company called aeromomentum that offeres a suzuki based auto conversion. I have developed a criteria for what I want. A lot depends on if you are able/ willing to do work yourself for the fwf components. The ea-81 can be made to produce the h.p., and enough weight removed to make it suitable for the 701, which I am also building. If I go that route, I can expect at least 6 more months of fabrication time. I would use a airtrikes spg redrive, custom made flywheel, oil pan, intake, with a cam regrind, and ported heads, with aeroinjector fuel delivery. All this requires extra work on one's part. If you are looking at a plug and play setup, be prepared to spend the money for someone's design,and problem solving. Support is critical if you aren't mechanically savvy. Parts availability, reliability, fuel consumption, tbo, and performance are also important. Oh yes, and cost. Many of are in the affordable category of flying. I look at the D motor, love the simple design, and basic direct drive, like the jabiru, but what are the weak points of this engine that time usually reveals? What are the parts availability, and support? Who's flying behind it? If I have to buy a plug and play, I would find a slightly used 2200, and make it work. There are some out there, and parts up-grades are available, and the engine, latest generation, has been refined. At 141 pounds, you will find the cg's suitable for most of the battery, and other necessities, can be mounted under the cowling, which comes in the fwf kit. The aeromomentum looks like a good conversion, and many parts are available at your local parts store. Their engine comes with a fwf kit for the 701. I do not have any specs on that engine for the 701, but there is one about to fly. For me, I have a mechanical background, I want a 4 stroke, at least 1500 hour tbo, 80-100 hp, easy access to parts, reliable, smooth, affordable, and have at least three people flying behind it to use as references for when you have questions. Another factor may be support. A few years ago, subaru conversions were all over the place, now not too many companies support them, so you will be on your own, but there are many people flying behind them to give you advice. On a budget, with a little help, and work on one's part it still makes a nice conversion for planes. Harmonics, and vibration are almost non-exsistent, you can swing a 70-72 in prop, and be considerably thousands less than those others. I have heard of those motors, with a 40 pound belt redrive, weighing 165 pounds, but it requires work. Hope this helps. Fellow 701 builder

 

 

Good folks, know their stuff, and will be a great builder support. Waiting on their first 701 rollout. Thanks

 

 

Just Landed! Am located stateside. Building a zenith 701. I am a better than half way. Looking for engine options, I have some subaru Ea-81's, and 82's. Have looked at Jabiru. Only looking at 4 stroke, close to 100 h.p., decent rate of climb, dependable, and reliable, easy to get parts, all at an affordable price in the U.S. Sound crazy? Ideas?