Which Engine???

October 29, 2006

Hi ! I'm a new player, having finally bit the bullet and ordered a Zenith CH-701. (Ya, I know, not the most beautiful thing..but it appeals to me!)

I'd just about decided on a Jabiru 2200 for quite a few reasons including...a freind of mine has a 3300 in his Europa, and it's been great !..I'm not that keen on an engine humming along at 5000 rpm all the time (wear, noise, etc)... and..I think that Rotax is a bit pricey in comparison to most others.

But, I just read a 701 review in Recreational Flyer (Canada May-June 2005) that says...

"Choose an engine that will develop 80 hp and can turn a 68-72" prop, and weighs less than 200lb"

...and......

"Right now the only engine that will make the 701 perform is the Rotax 912 or 912s"

This is a bit confusing to me 'cos the 2200 spec calls for 62-64" prop.

I thought this was all about torque...and the 912 (76 lbft @ 4800) and the 912s (94 lbft @ 5100) produce substantially less than the Jabiru (158 lbft @ 2500) !

Any advice would be most welcome...I sure don't wanna buy the wrong engine first time out!

Thanks,

Steve

October 29, 2006

you might do well to visit a local chapter of the SAAA they are the kit building specialists, and many members have heaps of experiance, though as with any advise come of it will probably be contradictory.

the question to ask is why they feel that way, so you can work out what will best suit your circumstances.

Regards,

AusDarren

Ultralights · October 29, 2006

dont forget the rotax produces less torque at the crankshaft, but it has the advantage in torque amplification through its gearbox!

Student Pilot · October 29, 2006

I would have thought the bigger draggier fuse on the 701 wouldn'd have suited the smaller diameter Jab prop. Thought about the 582 or have you decided on a fourstroke? They aregood lightperformers with 582's.

pylon500 · October 30, 2006

Although the Jabiru 2.2 is supposed to put out 80hp like the 912, it will only do it to a small prop, which is not as efficient as a larger prop.

Another point to consider is the flying speed of the 701, will you get enough cooling at full power at climbing speed?

Some of us still don't mind two strokes for their power to weight ratio.;)

Then there's the other assorted geared (belted?) automotive engines.

Arthur.

October 31, 2006

Ya see..that's the bit I don't understand !the geared 912 even with torque amplification of a gearbox STILL doesn't put out as much torque as the Jab 2.2 ! So why the smaller prop size?

The 582 apparently is too small for the 701 (aside from the 2 stroke noise!

What about the geared vw (RGTT 2000)... apparently produces over 200ftlbs !

AeroVee (ungeared vw) Sonex states that it will have the same performance as the JAB 2200

EcoFly and Masschi also produce some interesting stuff, if you own a goldmine !

I guess what I need to do is get some info from 701 owners with different engines re: performance.

October 31, 2006

Hi guys

I have built and seen in action R582 equipped 701. This little 2 stroke engine when it comes on song takes some beating. Seems to perform much better than it's 65 hp seems to indicate. The slats on the 701 keep down speed anyway, so there's not much to be gained pumping in the power. Anyway, it's lighter, and without the added weight from the wing tanks doesn't seem to make that much of a difference. (compared to a subaru ea82, 100hp, Amax redrivethat I assisted with at one time) The primary structure was extensively modified/changed for this.

One point to note, you may only be able to register under the earlier 450kg. If such is the case every kg counts, that's why I selected the R582 in the first place. The structure doesn't eaxactly inspire confidence for heavier engines, so beware.

If you must have a 4 stroke, the 912 would be hard to go past, esp as an engine foward kit is specifically made for either R582 or R912 (Jab, I don't know)

There is higher power 2 stroke,although few seem to show much interest in them, hirth. Amost whatever power output you like. I find it interesting why they haven't caught on.

As for jab, it's at a bit of a disadvantage without gear reduction. It compensates for this by using a smaller diameter propeller (tip speed) in an attempt to get engine revs inside a reasonable rpm band, but even so it's still a bit low (rpm) for a 4 stroke.

My 2 cents worth, Micgrace

Student Pilot · October 31, 2006

The reason the Jab has a small prop is to keep down tip speed. I think the 701 was originally designed with the 2 stroke in mind, there are some nice 701's around with the 582. I have seen a 701 with an 0-200 Continental, it was way too heavy, I don't think it even flew.

November 1, 2006

Thanks Guys! Information is extremely useful !!!!

..Can anyone give me comparative 701 performance details with 582 vs 912?

I actually ordered the wing tanks option..you think don't use them with 582 if I go that way?

Hirth engines are now readily available in Australia (AATI Pty Ltd) and appear well priced..but there are so many horror stories on the netabout their lack of reliability/service that it's a bit scary.

Does anyone know of a 701 with a 582 currently active in Australia that I might get some feedback from??

Thanks again,

Steve

November 1, 2006

Hi

If you ordered the wing tanks use them, good extra. I'd go for the 912 if you can afford it.

<T>

<TR>

<TD =#ffff00>SPECIFICATIONS</TD>

<TR>

<TR>

<TR>

<TD>LENGTH</TD>

<TR>

<TD>HEIGHT (rudder tip)</TD>

<TR>

<TD>EMPTY WEIGHT*</TD>

<TR>

<TD>GROSS WEIGHT</TD>

<TR>

<TD>USEFUL LOAD</TD>

<TR>

<TD>WING LOADING</TD>

<TR>

<TD>POWER LOADING</TD>

<TR>

<TD>DESIGN LOAD FACTOR (ultimate)</TD>

<TR>

<TD>CABIN WIDTH (shoulders)</TD>

<TD align=middle>40 INCHES</TD>

<TR>

<TD>CABIN WIDTH (optional bubble doors)</TD>

<TD align=middle>44 INCHES</TD>

<TR>

<TD>FUEL CAPACITY (std., dual wing tanks)</TD>

<TD align=middle>20 US Gallons

(2 x 10 gal.)</TD>

<TD align=middle>76 liters

(2 x 38 liters)</TD></TR></T></TABLE>

Click here for a full-size view | Click here for additional detailed views of the STOL CH 701

<T>

<TR>

<TD width="40%" =#ffff00>STOL CH 701 PERFORMANCE</TD>

<TD align=middle width="30%" =#ffff00 colSpan=2>ROTAX 912 (80 HP)</TD>

<TD align=middle width="30%" =#ffff00 colSpan=2>ROTAX 912S (100 HP)</TD></TR>

<TR>

<TD align=middle width="15%">SINGLE</TD>

<TD align=middle width="15%">SINGLE</TD>

<TR>

<TD width="40%">TOP SPEED (MPH)</TD>

<TR>

<TD width="40%">CRUISE (MPH)</TD>

<TR>

<TR>

<TD width="40%">STALL (MPH)</TD>

<TR>

<TD width="40%">RATE OF CLIMB (FPM)</TD>

<TR>

<TR>

<TD width="40%">LANDING ROLL (FEET)</TD>

<TR>

<TD width="40%">SERVICE CEILING (FEET)</TD>

<TR>

<TD width="40%">STD. RANGE (MILES)</TD>

<TR>

<TD width="40%">ENDURANCE</TD>

Range and endurance figures are quoted with no fuel reserve. Figures are based on factory prototype results, and are subject to change or revision without notice.

Engine Limitations: 50 - 100 hp, up to 185 lbs. installed. Alternative engines will affect performance, specifications and flight characteristics of the aircraft. Also, the weight and balance of the aircraft may be adversely affected by alternative engines, and the original fuel system may not be adequate or suitable for some engines. Most alternative engines will require a custom engine mount and engine cowl. Zenith Aircraft Company does not manufacture or directly support engines.

<T>

<TR>

<TD align=middle>STOL CH 701

True short take-off and landing capability for the serious sport pilot.

Flying the STOL CH 701:

"You're already where you want to be!"</TD></TR>

<TR>

</TD></TR></T></TABLE>

Micgrace micgrace

Ultralights · November 1, 2006

why cant all speeds be in Kts....

November 1, 2006

in the USair speed indicators are in MPH, European is KPH and mtrs for the alti. and vsi. And of course kts for us. Whats a knot? it's part of a log!

November 2, 2006

Hey, this is great! If I keep this up I may actually KNOW something when I'm finished! lol

Seriously, good information abounds! 701 was actually designed for 2 stroke twin...and proponents are probably correct re weight vs low speed performance!

As such now seriously looking at Simonini Victor 2, 92hp, water cooled 2 stroke/very light, excellent reports from contacts all around the world (well...5 anyway!), and it is significantly cheaper than competition (about $9000 Aud), 2.67/1 gd (among others) swings 68-72" 3 blade!

Response from NZ states "900-1100 fpm climb@5000 rpm...exceeds Vne level flight @ 6000rpm"

Response from US states "Totally satisfactory performance (exceed ZAC specs!140hrs without any problems"

Comments?

pylon500 · November 15, 2006

With the lighter all up weight of using a two stroke, it would be better to include your wing tanks to keep up with the fuel consumption rate.

Two strokes are a bit like Rotarys, you don't get that much horse power from such a small engine for free, it cost fuel!

Still, you have to do a lot of flying to really notice the difference.

Just as a side note, the Jabiru initially flew with a two stroke. :ah_oh:

Arthur.

Yenn · November 16, 2006

Concerning 2 Strokes as against 4 stokes Arthur has come up with the real difference.

I have found that there is a great difference between 2 and 4 stroke fuel consumption, practically 50% greater for 2 strokes so you have to carry the weight saved as extra fuel

Another problem is the need for 2 stroke oil at about 400ml per 20 litres of fuel. On a long journey you will need to carry more fuel plus the oil for it and measuring equipment for when you buy fresh fuel.

Personally I prefer 2 strokes although I have had more engine problems with 4 strokes. I have had carby ice in a 2 stroke, but it is more common in 4 strokes. I have had a burnt valve in a 4 stroke which cannot occur in a 2 stroke , but that one was LAME maintained and GA registered. If you treat a 2 stroke according to the manufacturers recommendations it will be very reliable, but old blokes like me have long memories of unreliable 2 strokes from the days of poorer oils and fuels.

Jethro Belle · July 26, 2018

As such now seriously looking at Simonini Victor 2, 92hp, water cooled 2 stroke/very light, excellent reports from contacts all around the world (well...5 anyway!), and it is significantly cheaper than competition (about $9000 Aud), 2.67/1 gd (among others) swings 68-72" 3 blade!

Did you ever go ahead with the Simonini Victor 2 Motor ? Their website now gives the standard 764cc engine output at 102 and the 800cc 110hp. That is more than the Jab2200 and into Rotax914 teritory! They also claim - No carbon residues- consumption lower than 4 stroke engines- 450hrs with no maintenance! Fuel consumption looks very good. How are they doing it with Bing carburetors?

Simonini has been officially active in the USA since 2005, so they must be doing something right. It appears they have had some engine failures, but I haven't found any statistics. Has anyone?

GGenghis the Engineer throws doubt on the claimed horsepower figures. Anyone know if the he is right?

Is anyone running the bigger Simonini two strokes? I believe the smaller engines are commonly used on paragliders and the Victor 2 on the X-Air ultralight.

microman · July 26, 2018

I had a Skyranger with the Simonini Victor 2 (rated at 92 hp). Based on my experience with the engine I would not buy one again, Yes - the claimed hp figures are dubious at best, the claimed fuel consumption figures are a joke ( I normally used 15-17 l/hr at slow cruise). the gearbox had several faults which we discovered before any real damage was done, the heads had not been properly torqued, causing a blown head, vibration was a major issue ( somewhat improved by fitting a 3-blade prop), noise was also an issue - even with an ANR headset. Oh, and because it had to be installed upside-down, you had to clean the plugs virtually every time you flew before it would start.

Apart from all that it wasnt a bad engine. Its still operating after 350 hours and needs little maintenance. In summary, if you can put up with the vibration and noise its probably quite good value for money.

Thruster88 · July 26, 2018

Fuel consumption claimed for the Simonini Victor 2 is bullshit, it's a basic carbureter two stroke. A direct injected (E-tec) two stroke can get close to four stroke fuel consumption Rotax have them in snow mobiles.

facthunter · July 26, 2018

Draggy planes need bigger area props. to get THRUST. ( Move a bigger mass of air) Have a look at the Sopwith CAMEL prop size. really large. They did 1200 RPM and about 110 horsepower Rotary engine with lots of torque. You can gear other engines to get similar effect. Jabs are light and cheap and they don't rev very high. Perhaps they could run a bigger dia prop. They don't like being lugged though, ( over propped) so you might need something a bit more efficient than the wood one and less pitch. Nev

Kenlsa · July 27, 2018

One of our members ran a jab 2200 in his 701 and with a 42" pitch prop suffered from temp problems. He talked to Jabiru and got a 38" pitch prop that cured the temp problems and still gave him 75 kts cruise.

Ken

derekliston · July 27, 2018

One of our members ran a jab 2200 in his 701 and with a 42" pitch prop suffered from temp problems. He talked to Jabiru and got a 38" pitch prop that cured the temp problems and still gave him 75 kts cruise.Ken

Same pitch as my Jab 2200 in my CH701. 75kts cruise is good but ground speed Warwick to Pittsworth today was 55kts. Return though was 85kts ground speed!

stol1 · July 27, 2018

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

jetboy · July 27, 2018

Although the OP is 12 years ago I'll add to the discussion

My 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

My solid lifter 2200 has done 550 hrs now with new rings (a known issue with pre - 2006 builds) its doing OK if it gets to 1000 I should be happy.

If not I have put a label on it DNR (ask a paramedic) as if anything major breaks there are not worth rebuild and they are onto Gen4 production now.

I would not consider a used 2200. There is not enough track record on the new ones. D-Motor is my favourite prospect although there has been 1 failure around the head sealing. I dont do high hours so a 582 is still a good option. Heavy airplane is not happy airplane. The 701 doesnt need more power. Get a 750 or 801 for that role.

facthunter · July 28, 2018

Maybe there were other factors as well as the diameter change. It's always been the case of more drag needs thrust to counteract it. Less drag like a Corby Starlet with a Jab works well.. The Rotax 2 strokes are all geared and are quite versatile over a wide range of planes. So are the 4 strokes of the same make. You lose a little bit (friction) in the gearing but the torque is multiplied enabling a larger diameter prop be involved with more air mass and letting the engine develop more HP by doing more revs. Gear drives weigh a bit. and cost a bit.. Nev.

stol1 · July 28, 2018

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?

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