[grjtucson]

All,

Robbie Attaway just posted an ECI kit in classifieds and rather than respond in that thread, I wanted to respond here and solicit input at the same time, hopefully to get a wider set of eyes seeing this post.

Robbie's kit is high on my list as you'll see. He and I met at last year's LOE and we've talked on the phone. I'm very interested in building an ECI engine and if not this kit, perhaps another in the future.

For everyone, I'd welcome your thoughts as I haven't committed to anything yet, but need to soon. Here's my thinking now:

ECI IO360 Parallel Valve, low compression, cold air sump, ECI fuel injection (I'm plumbed for returns to each tank), Hartzell BA CS prop, probably emag/pmag.
Pros: lots of speed/horsepower, well established install other than the ECI FI perhaps. If I go with Robbie I can go up to Phx from Tucson and build it with him, otherwise there is no shortage of well established vendors w/great reps.
Cons: expensive, but only because I'm going with what I want
Current Position: front-runner

IO390X Angle Valve, cold air sump, Hartzell BA CS prop, probably emag/pmag.
Pros: more than lots of speed/horsepower, plenty of nose weight, cool factor is high.
Cons: more than expensive, not as well established install, not sure if there's a way to participate in the build
Current Position: 1st choice if not for the hard time spending the extra 8-10k over the parallel valve, not sure the extra money provides the return

Chevy V6 from Belted Air Power / Jess Meyers, Prop ?
Pros: way less expensive, curiosity/cool factor, cheap parts/rebuild, high poss. of easier auto gas use in future
Cons: waaaaay less established install/support, more experimenting, lower speed/horsepower, CS prop is difficult I believe, way less info available now to make educated decision, single point of failure for availability of some parts/components
Current Position: dying to see one/hear one/fly one and hope to at Copperstate or LOE. I probably hunger for details that do not yet exist. Will even jump in Decathalon to see Jess in Vegas if needed. In the running, but 3rd.

Egg Subaru H6, MT or Quinti CS Prop
Pros: well established and from what I can tell quite easy install, support is solid w/large and enthusiastic user community, high cool factor, low vibration/smooth I'm told, high poss. of easier auto gas use in future
Cons: lower speed/horsepower, very high cost, electric CS props are spendy and slower to respond, need for somewhat more robust elec. system, single point of failure for availability of some parts/components
Current Position: still in running but cost vs. speed/horses is biggest issue, running 4th at this point but not out of race by any means


I'm building an RV7; the wings are almost done and the fuse. kit is nearly inventoried. I'm thinking 8+ months before I'll need an engine, maybe longer if I order and build the finish kit prior to hanging the engine, but I'll definitely need to make the decision long before that.

I really do want good speed and have pretty much decided on a Sam James cowl and plenum (I'm a desert rat too so cooling is an issue). I am very open to advice/suggestions/sales pitches and don't have any sacred cows that will mind skewering - bring it on! If there are other things that'll help besides cowl & plenum, or if there is an engine/prop combo I should add for consideration, I welcome those in addition to thoughts about my current menu. Specific info and experience on fuel injection choices, ignition choices, and cold air sumps is all encouraged.

I do know I can save money with a used 320 or 360, fixed pitich prop, carb, and/or mags. Cost, though, is really not as big a factor as others. Auto gas is also not a big deal as I don't care to haul it or store it and at the moment I don't really have a decent local source.

I plan to be at Copperstate at least one of the days and at LOE for the weekend, perhaps w/my Decathalon (I0320 / CS), weather permitting this year. I will gladly buy fuel for rides in planes with engines that I'm considering, and definitely won't be shy about asking for your thoughts or to discuss your install.

George

 

[Jconard]

I went through the same thing.

1. If you want the traditional James cowl, with thei intake (which is cool), you need an extended hub prop. Their stubby cowl version uses the van's intake. The traditional James intake will get you a great settup with the ECI Front intake, and streamlined servo.

2. The cheapest way to get such a hub and still have CS is the Whirlwind 151, which they will deliver with an extended hub at no additional cost.

This prop is not to be used with non-counterweighted 360's, but it should have good performance. When I looked at them I read a review which had the 150 (Fat Blade Version) as 3 mph slower than a Hartzell. However, WW claims the tapered blade 151 gets all that speed back. I have consulted with a O-320 Glasair owner who says he picked up 10+mph when he switched from the 150 to the 151...guy has a reputation for modesty on the local airfield. It is also only 29 pounds, and comes with a finished and installed spinner.

3. I went with an O-320 for the above reasons, and because I bought a first run which with new carbs, mags, Lycon flowed cylinders, custom pistons, and a professionally rebuilt lower end has only cost me $12,500. I got a lucky deal.

4. If it will work with the above prop, I would go with the IO-340. Not so much for cost, but it is lightweight with good power. You could go with Van's 320 mount which places the engine 2 inches forward, and gives plenty of room between the engine and firewall. Additionall, it gives the plane a sexier look (IMHO).

5. I would stay away from the 390 in a 7, just because I think it is overkill. On the other hand, you just can't beet the Barretts for knowledge and quality. It is big and a little heavy, and will require some fabrication to make the front mount governor, and larger oil cooler work. See http://www.io-390.com/ for one builders experience.

6. I would not install the V6 because, as in all auto conversions, it will be heavier, and will be slower/fuel because of drag and other issues. If you are willing to spend the time and effort, I am sure many of these issues can be worked out, but after how long?

7. The Egg install is not as simple as many believe. The extra wiring and systems are also not trivial. Again, personal preference, but ask to see the wiring diagram, fuel system layout, and electrical requirements, it is extensive. Weight and speed will also be an issue. check out http://brian76.mystarband.net/rv7a/RV-7Ahome.htm. Many of his issues are related to the supercharged engine, but you will also see the wiring, fuel, exhaust and other systems.

8. In case you want to add a rotary to the list, here is a website that has some real answers: http://www.rotaryaviation.com/, there are several, future pilots, and non plane owners who will boast to you about power and weight, but you will find that weight is still generally higher, and performance/fuel generally lower, or even with the lycoming on some metrics at best.

If you are an engineer, have skill, tools, and a pioneering spirit, it seems like the auto conversion would certainly be entertaining, and those who have made it work seem convinced that it works well. Check out SDS's RV-10 for a glimpse of what it takes to do it right....we still don't know if the approach there will address the weight/drag/speed/fuel issues, but if anyone can they probably will, and others have not (in decades). http://www.sdsefi.com/air46.htm

Finally, as I move along on my current project, it is becoming clear to me that I must build another one. The only way that can happen is if I can sell this one. The further you get away from proven systems, the harder it will be to sell your plane to build your next one.

Just my thoughts, but I would be particularly interested in simplicity and weight. A little self control firewall forward can lead to more room for a nice big panel, or clear the way to a simple, hence reliable, light plane.

JMHO

 

[gmcjetpilot]

How much HP do you need

I'm building an RV7; the wings are almost done and the fuse. kit is nearly inventoried. I'm thinking 8+ months before I'll need an engine, maybe longer if I order and build the finish kit prior to hanging the engine, but I'll definitely need to make the decision long before that.

I really do want good speed and have pretty much decided on a Sam James cowl and plenum (I'm a desert rat too so cooling is an issue). I am very open to advice/suggestions/sales pitches and don't have any sacred cows that will mind skewering - bring it on! If there are other things that'll help besides cowl & plenum, or if there is an engine/prop combo I should add for consideration, I welcome those in addition to thoughts about my current menu. Specific info and experience on fuel injection choices, ignition choices, and cold air sumps is all encouraged.

I do know I can save money with a used 320 or 360, fixed pitch prop, carb, and/or mags. Cost, though, is really not as big a factor as others. Auto gas is also not a big deal as I don't care to haul it or store it and at the moment I don't really have a decent local source.

Good post, sounds like you have a handle on it. I am going to say respond a Lycoming 360, 180hp and hartzell BA prop. That is the best combo. Your comment of going with a SJ cowl is fine. Cooling is NOT an issue. If you do go with an angle valve put a HUGE 12 row cooler in and a 4" scat to it. The IO360 angle valve is cooled by oil and cool oil leads to cool everything else.

I don't know Robbie except from his web site and had some email correspondence. He seems like he does real nice work. Plus he's in your neck of the woods. Considering my first comment, get a Lycoming (any model you like), the advantage of going with a big company, mattituck or aerosport is warranty. Also most big shops offer dyno break-in and checks at base cost or a slight charge. Both of those may be worth extra cost to you. That is a decision you must make. There is nothing wrong with breaking in a new engine on the plane, especially one made of new parts.

I don't like the ECI FI. Don't get me wrong, I LIKE ECI, good people and products. I am sure they will make nice FI parts but the designed is poor. Also it is not cheap, it is not a true fuel injection, it meters fuel on RPM and guesses at the right flow. This is unlike others (Silver Hawk Precision, AFP) which are mass air flow. With the ECI you will need to actively lean in climb, especially if going to high altitude or you will waste lots of fuel. This is a direct copy of an old Continental type injection and is a compromise. Some later Continental installations use altitude compensating fuel pumps to help with the altitude adjustment. From a Kit Planes article on ECI's FI, they are quoted as saying it is in between a Carb and FI. Either get a Carb or get FI, the ECI is not a great design. Now ECI as a company is great. I know they make excellent quality parts, but the basic design of their FI is just not up to snuff.

As far as you comments on spacific models, IO390, Belted Air power, Subaru, ahaa, I think your assumptions of cost may be off. Nothing is way less expensive. A IO390 will be way more than a 10k than a basic 180HP lyc and the alternative's will NOT be way cheaper than a basic 360 parallel valve; in fact in the case of the Subaru, the 180 Lyc will be cheaper I think. Bottom line you say money is not an issue. If you have a $45k or $55k engine / prop budget than it does not matter.

I don't know the details about the IO390, I forget, they stroked it, bored it out, did both, plus may be bumped the compression. Regardless the words "short fuse" comes to mine. No doubt it will be reliable, but it is "strung out more". The more HP you make the sooner it will wear out. Just a fact of life and a thought.

If you are a hot rod racer and have dreams of grandeur about being the fastest guy on the field, have the money, go for it, especially if on an unlimited budget. I talk to two kind of people, those with means and dreamers. I say to the folks with bucks get what they want, if it makes sense. From your logic, it sounds like you have a good grasp on it. To the dreamers I say your RV will fly fine with a mid time 150 hp lyc and fixed prop. It is better to get into the air than dream about it. Also it is fun to go fast on less. My 150 HP RV-4 out ran almost all 160 hp RV's and many a 180 HP RV.

Weight wise the RV-7 may take a IO390 from a pure CG and W&B just fine, but if you have low RV time or points of refrence, I can tell you light RV's are a delight to fly. This is subjective and must be experienced to be appreciated.

A 150/160/wood prop is a fine plane, not for you but just in general. With any angle valve you are on your way to a heavy boy. To get back some of the extra weight from the engine, you have to compromise with less, paint, interior, panel or use a light weight (expensive prop). The problem with the latter is you are giving up some significant performance by not using the Hartzell BA prop, which is of course metal and heavier than say a three blade whirlwind. I believe Hartzell now has a BA prop for the IO360 angle valve, not sure if it is approved on the IO390. (Les?)

If you are going for pure performance, dual Lightspeed III's are the way to go. E/P-mag is a good system but not a performance system. They are better than mags for performance, but if you are going for the gold, the top performance will be LS.

If you make a heavy plane because you want the big engine and not willing to compromise on the goodies, comfort and paint, next step will be raising the the max gross 1800 lbs, as recommended. Many RV's are solo acro planes because of heavy empties. If you are not into acro than that is a moot point. I am for light weight.

Last it is easier and better to go fast with less drag like a SJ style cowl, which can make up to 8-10 mph difference. That is almost like 20-25 HP, from 180 hp to 205 hp. Reduce drag verses add HP. An extra 10 HP may only be 3 mph. Just a comment, speed cost money.

For goodness sakes it is a two place small homebuilt. How much HP do you need? Good luck with you decision. I know you will be happy with a IO360 parallel Lyc with a Hartzell-BA prop. If you step up to an angle valve consider making some light weight decisions with the accessories. If you want a full IFR platform with a fancy custom paint job, I would go with the light engine for sure.

 

[frankh]

decisions, decisions

George, make sure you join my Yahoo group dedicated to the Sam James cowl...Except the company likes to be called "James Aircraft"...so you won't find "Sam" in the name.

Do a search for it on Yahoo. I set up the group cus there was very little info on how to fit one of these cowls and plenums. A lot of good info is shared there. You can save a few pannies by not using the Van's baffles and making your own...you will need 4*4' of alu sheet.

The cowl takes more time to fit without a doubt but it looks hot...You can find pics of my paint job on van's or at the yahoo group. even the slightly longer nose looks better than the standard Vans...my personal opinion.

The Ema/Pmag combo is just awesome for quick timing...Once you got the units mounted in any orrientation you can time the engine in less than 5 minutes...so easy its unreal.

I don't know why George thinks the Emag is not a performance system...it has almost completly viariable timing and you program any curve you want from your laptop.

I would avoid a mounting an Airflow performance FI on a FF sump...The AFP servo is longer and you will have a heck of a time getting it all to fit...see the yahoo group.

The Bendix is shorter so I would use a Bendix servo with AFP nozzles and purge valve...should help a lot if you decide to use Premium mogas like I do.

I hung the Hartzell Compact hub prop on a 2.25" extension...Shock horror, but I don't see it as an issue after talking to a lot of folks. The Sabre extension is $350 approx...Still the cheapest prop with the best speed I think.....Remember the F1 rocket guys are using Hartzell Extended hub props (i.e pretty much the same as an extension) and I can guarantee you they are not flown straight and level...hartzell will tell you th extended hub prop is NOT rated for aerobatics.

CG wise it works out fine, if you go with the angle valve motor this might get a bit nose heavy.

The alternative is to save yourself about 2.5 grand and go with vertical induction...and no prop extension.

The paralell valve 360 is MORE than adequate(FF sump, flowed heads probably means I have a few more ponies)...IMHO after a whole 13 hours in the cockpit.

If you are serious about alternative engines remember the resale value may or may not hold as well as a Lycoming engined airplane.

Frank

 

[gmcjetpilot]

George, make sure you join my Yahoo group dedicated to the Sam James cowl...Except the company likes to be called "James Aircraft"...so you won't find "Sam" in the name.

Thanks I belong and I am a charter member to the james aircraft yahoo group. Is there another group?

Do a search for it on Yahoo. I set up the group cus there was very little info on how to fit one of these cowls and plenums. A lot of good info is shared there. You can save a few pennies by not using the Van's baffles and making your own...you will need 4*4' of alu sheet.

Way a head, already doing that, using Dave Anders rings and making my plenum per tracy saylor. I started my first RV in 1986, now working on my third, a RV-7. Sounds like we have like ideas.

The cowl takes more time to fit without a doubt but it looks hot...You can find pics of my paint job on van's or at the yahoo group. even the slightly longer nose looks better than the standard Vans...my personal opinion.

My RV-4 had a long cowl and extended hub hartzell, but I elected to go with the stock (short) cowl and mod it be similar to "JAMES AIRCRAFT". This way I could use the less expensive and available BA hartzell. To be fair we should call it a NASA/Mississippi State/Texas A&M/Miley/Cross/Owen Cowl. I knew about the cowl when Barnard was making them, before Sam James took it over.

The Ema/Pmag combo is just awesome for quick timing...Once you got the units mounted in any orientation you can time the engine in less than 5 minutes...so easy its unreal.

I don't know why George thinks the Emag is not a performance system...it has almost completely variable timing and you program any curve you want from your laptop.

Well I can tell you. The E/P-mag is an inductive coil ignition, aka GM, single coil. I mean you have one little coil firing all 4 jugs. The Lightspeed it a multi spark discharge CDI (capacitance discharge ignition). Nothing wrong with the former but it is not as high performance. The LS has a coil per every 2 cylinders, discharge is longer and hotter (stronger) and runs on lower voltage. Not to mention LS offers cockpit advance, map, rpm out put and cockpit variable timing. It is just a higher performance ignition system.

The E/P-mag is good for a daily flyer and if you read there literature they say so. They are not going for the racing market. My comments are in light of max performance. Unless they just changed it, they don't allow user programmable timing changes, but if you send it in they will do it for you. LS can change the "programmed" timing for you as well, but as I say you have the option to manually change it while flying. I would not recommend that unless you really know what you are doing.


I would avoid a mounting an Airflow performance FI on a FF sump...The AFP servo is longer and you will have a heck of a time getting it all to fit...see the yahoo group.

That is an advantage of the ECI's new FI system as I understand it, is its even shorter.


The Bendix is shorter so I would use a Bendix servo with AFP nozzles and purge valve...should help a lot if you decide to use Premium mogas like I do.

Not to nit pick but Bendix is dead, it is precision or really they like to be called "precision airmotive". The product is the silver hawk EX. As far as mogas, I think he said he was against it, but using it in an angle valve is way out there. The stock IO360 +200HP ang valve is 8.7:1, way to much for any current automotive octane. Remember 92 at the corner gas station is 87 octane in av gas. Even a 180HP on premium auto gas is just marginal. Yes retard timing and cool the gas with every means possible, but I think auto gas is best suited for the 7 and 7.5 to 1 engines, aka 150 hp. Also tight cowls are heck on autogas and vapor lock. The Mooney could not pass STC mustard for auto gas, with a 180HP O-360. The consensus is the faster the plane and the tighter the cowl the less suitable autogas is. If you want autogas de-rate your compression ration down to 7.5:1 to one. I think a 360 with that CR is about 168-170 HP. Forget the 160 HP O320, they are 8.5:1. There is a reason Lyc made most of its engines 8.5:1 or less.


I hung the Hartzell Compact hub prop on a 2.25" extension...Shock horror, but I don't see it as an issue after talking to a lot of folks. The Sabre extension is $350 approx...Still the cheapest prop with the best speed I think.....Remember the F1 rocket guys are using Hartzell Extended hub props (i.e pretty much the same as an extension) and I can guarantee you they are not flown straight and level...hartzell will tell you th extended hub prop is NOT rated for aerobatics.

CG wise it works out fine, if you go with the angle valve motor this might get a bit nose heavy.

You got into a place where you needed an extend length hub but none where made for the angle valve. I would not do what you did. Now "James Aircraft" makes a short cowl. The only issue is as you point out making room for the fwd servo.


The alternative is to save yourself about 2.5 grand and go with vertical induction...and no prop extension.


That is a great idea and suggestion. You can even use a elbow on the bottom of the sump and turn the servo forward like this gent did. http://www.lazy8.net/intakesystem.htm. You can purchase that elbow.


The parallel valve 360 is MORE than adequate(FF sump, flowed heads probably means I have a few more ponies)...IMHO after a whole 13 hours in the cockpit.

If you are serious about alternative engines remember the resale value may or may not hold as well as a Lycoming engined airplane.

FrankI agree 100%, good points

Cheers George

 

[Allen Barrett]

High Strung?

George, I'm not quite sure what you mean by strung out more. The IO-390 uses 8.9:1 compression, .2 more than the angle head 200 HP 360 (stock compression in the bigger displacement cylinders.) The engine was not stroked, only bored. Don't read into this that we took IO-360 angle head cylinders and took material out. We didn't. Except for the barrels, pistons & rings, and piston pins, oh and stamped rocker covers, the engine uses the same parts as the 200 HP angle head. Same rods, cylinder heads, valves, crankshaft, and except for the engine being offered with roller cam and followers, the same cases. Furthermore, the engine has a rated TBO of 2000 hours. The weight difference is 8lbs over the angle head.

Just clearing the air,

Allen

 

[frankh]

E/Pmag features

I don't know why George thinks the Emag is not a performance system...it has almost completely variable timing and you program any curve you want from your laptop.

Well I can tell you. The E/P-mag is an inductive coil ignition, aka GM, single coil. I mean you have one little coil firing all 4 jugs. The Lightspeed it a multi spark discharge CDI (capacitance discharge ignition). Nothing wrong with the former but it is not as high performance. The LS has a coil per every 2 cylinders, discharge is longer and hotter (stronger) and runs on lower voltage. Not to mention LS offers cockpit advance, map, rpm out put and cockpit variable timing. It is just a higher performance ignition system.

The E/P-mag is good for a daily flyer and if you read there literature they say so. They are not going for the racing market. My comments are in light of max performance. Unless they just changed it, they don't allow user programmable timing changes, but if you send it in they will do it for you. LS can change the "programmed" timing for you as well, but as I say you have the option to manually change it while flying. I would not recommend that unless you really know what you are doing.


Actually things have moved on in Emag world You can alter the max advance via a laptop connection and their software download. They are soon to have a cockpit controller...not sure if that is just a monitor or if you can make changes on the fly with it or not.

What really stands out for me is setting the timing...You bolt the emags in place and rotate the prop to TDC then blow hard into the map tubes twice and the timing is automatically zeroed.

No back and forth numerous times to get it right.

Slick eh?

Frank

 

[grjtucson]

Some Answers and More Questions

Thanks to all for the responses, I am inching my way forward in understanding. Here are some answers to questions that have come up:

1. I just joined the James Cowl group, thank you (assuming the invite was for me, not George M. who is a long time member I believe).

2. I do want positive g aerobatics. It sounds as though a prop extension makes that either bad, or at least not recommended. Should I then use the stubby James cowl?

3. I suspect I will only paint my plane when I'm ready to sell it, but who knows. I am very much a function over form guy. I'm looking for light weight, minimal interior, but IFR panel.

4. I'm not ready for rotary, more from a weight perspective than anything. V6 and Egg are bottom of list for weight as it is.

5. I have a limited pioneering spirit - I really want a fairly simple and light plane. I am intrigued by the conversions, but they are at the bottom of the list for the complication factor as well as the weight.

6. Speed is my top concern, I already have a 120mph plane, I want a "go fast" plane that my wife won't complain about having to stare at the back of my head in. Speed from efficiency and drag reduction is better to my way of thinking than from HP and burning more fuel, but I still want as close to 200mph cruise as possible. I don't need to be faster than anyone, no racing, just want 200mph cruise if possible.

7. I really am interested in learning by building or participating in a build.

8. I'm probably going to put off the ignition decision as long as possible as it has less bearing on airframe building now. That said, more info is better.

Now for some questions that have come up:

1. Are all forward facing sumps also cold air sumps?

2. If not, how much value is there to FF over updraft if neither is cold air? Is is worth the expense in your opinion?

3. How valuable is a cold air sump? Worth it?

4. Value of ram air?

5. Your opinion, Carb vs. AFP vs. Precision Airmotive Silver Hawk vs. ECI?

6. Counterweighted vs. non-counterweighted parallel valve 360?

7. Roller tappets or not?

I really appreciate the expertise here, and also definitely sense that others are stepping their way through these decisions as well, so hopefully the discussion is benefitting all.

George

 

[Jconard]

The only question that I have an opinion on is the acro work and extended prop.

There is of course more load caused with a heavy prop and extended hub. This is why I went with the 151...29lbs which makes it lighter than a Sensenich.

I don't know, but suspect that you loose some speed with the stubby cowl. I am told that even though it is a three blade, the 151 is as fast as the hartzell. Perhaps by the time you are ready, I will have flown and can get you some numbers.

I also value the idea of simplicity and that is why I went with the carbed, mag engine. I can tell you that installation is a real joy, all the Van's brackets work, though their cable lengths were too short....the mount is longer on a 320. If you go that route, I can provide you with the cable lengths. But it is super simple, two wires, one hose, and three cables. Other wires for engine monitoring, but in general a clean FWF installation.

I personally do not think that Fuel injection is really worth it in terms of weight, complexity, and starting. I owned a fuel injected plane before, and it was fine, but it was also a plane with inverted systems. Since I too only do positive G acro, I installed a carb. There is a good discussion under the FWF information links on this site.

Just my thoughts..

 

[gmcjetpilot]

Imprecise words

George, I'm not quite sure what you mean by strung out more. The IO-390 uses 8.9:1 compression, .2 more than the angle head 200 HP 360 (stock compression in the bigger displacement cylinders.) The engine was not stroked, only bored. Don't read into this that we took IO-360 angle head cylinders and took material out. We didn't. Except for the barrels, pistons & rings, and piston pins, oh and stamped rocker covers, the engine uses the same parts as the 200 HP angle head. Same rods, cylinder heads, valves, crankshaft, and except for the engine being offered with roller cam and followers, the same cases. Furthermore, the engine has a rated TBO of 2000 hours. The weight difference is 8lbs over the angle head.

Just clearing the air,

Allen

Poor imprecise words on my part, that really explain nothing. Thanks for keeping me honest. I read the Kit plane article and forgot where the extra 30 cu-in displacement came from.

I don't have any stress analysis on the crank and rods and so on, but my "logic" is, if you basically take the same engine and get MORE HP out of it, strain will increase proportionally. Not very scientific on my part, but what do I mean by strain?

I said it should be reliable, right. However it will run a littler hotter, with a little higher internal combustion pressures (more rod, bearing and ring loads) and therefore, more "strung out". Nothing wrong with making more HP, but it will burn more gas and possibly (who knows until it is tested in service) not last quite as long? The "No Free Lunch" rule. Nothing scientific just conjecture on my part based on some logic, faulty may be? I could be wrong, but it is experimental and NEW. I don't think anyone could predict a TBO. It may in fact have beneficial affects on engine life, however my experience with engines is the more you get out of them, the shorter they live. This life issue may be insignificant and even more so for those looking for more power, i.e. a trade off or compromise, TBO for power.

Thanks and I do think it will be a heck of and engine. The roller cam should have been done long ago.

 

[gmcjetpilot]

More good questions

QUOTE=grjtucson Thanks to all for the responses, I am inching my way forward in understanding. Here are some answers to questions that have come up:

2. I do want positive g aerobatics. It sounds as though a prop extension makes that either bad, or at least not recommended. Should I then use the stubby James cowl?

Yes you should use the stubby cowl than, but it is only a diff of less then 2". This is a must for a "NORMAL" prop. The issue is with the Forward facing induction (FI servo) I try to explain below, but there is no BIG advantage with FF induction IMHO. It's hard enough to stuff an air-filter in there with the longer cowl and FF induction. The approx 2" less makes it even more difficult. There are just no off the shelf components.

If you where building a RV-8, "Show Planes" has a James style aftermarket cowl for the RV-8, BUT it lets you use vans Horz FAB (filtered air box). That may be worth a look. http://www.showplanes.com/index_1024.htm

I don't think anyone has tried Van's Horz FAB with a James cowl. I know you would have to make your own internal plenum for sure. I talk about the "harmony" of parts below. They have to work in concert. If you make miss-match choices you will make a mess, increasing the amount of work you make for yourself. Some love being a Lone Ranger, something different. You have expressed you desire to work smart and make it simple and easy by using existing combs. Good idea! However you may not get everything you want. You have to make trade offs to make it work as a WHOLE, not a bunch of individual parts.


6. Speed is my top concern, I already have a 120mph plane, I want a "go fast" plane that my wife won't complain about having to stare at the back of my head in. Speed from efficiency and drag reduction is better to my way of thinking than from HP and burning more fuel, but I still want as close to 200mph cruise as possible. I don't need to be faster than anyone, no racing, just want 200mph cruise if possible.

My 150 HP RV-4 did over 200 mph and cruise a tad over 190 mph. Look at vans specs, they are pretty darn close. If you build and average plane, with the big parts lined up with the wind reasonably well, your engine is not a dog (low on power), you will make spec speeds or better, over 200 mph on a stock, 160HP engine, REALLY!! Carb/FI/Vert/Horz induction does not matter, 160 HP is good enough. However I would recommend the 180 HP, because it does not cost more and is heavier. In the case of the RV-7, it can be tail heavy. Van has always had an issue of fwd CG on RV-4's and 6's with bigger engines and metal props, so he compensated with his newer designs. In the case of the RV-7 he compromised to the point a 160HP/wood prop is not a good for CG/W&B. However Van is a smart guy, he knows the trend of builders is to make it heavier and add more power not less. Besides he has the RV-9 for the 160HP efficient, non-hot rodd'ers.

7. I really am interested in learning by building or participating in a build.

Absolutly, that is the reason to build an airplane. I assume we are talking about the engine still. I had an A&P fields help me rebuild the used engine I bought. It was fun and fairly easy. It is like subcontracting a house. All the technical stuff is sent out for cleaning, inspection and referb. With the new ECI kits, all new parts, it would be easy and fun to just build the engine your self. In the process you will save a couple of grand. I think engine shops do offer value, with workmanship warranty and test stand break-in, in some cases.


8. I'm probably going to put off the ignition decision as long as possible as it has less bearing on airframe building now. That said, more info is better.

You can't go wrong. Even Magnetos work fine. E/P-mag is a fine product, compact and self contained. I prefer having the electronics and connections away from the heat and vibrations as in the Lightspeed, but it cost a lot more, especially if you go with the LSIII. Just research each companies materal. LS has been around for a long time. E/P-mag seems like they have customer service in mind. A victim of there own success, they got behind in order filling. I also know they have improved there product. Lightspeed has done the same as well, but they are a little a head, thus the Mark II & III models Klaus now sells.

Now for some questions that have come up:

1. Are all forward facing sumps also cold air sumps?

Call mattituck, power sport. If you are NOT worried about winning races you may want a warm sump and vertical induction with vans air box. The good news is vans FAB works with the James cowl. There is nothing wrong with a "hot sump". You will pay more for a cold air sump. The above suggestion will save you time and effort. It is just easier to build.


2. If not, how much value is there to FF over updraft if neither is cold air? Is is worth the expense in your opinion?

Forward facing induction does NOT make more HP by it self. (more about ram air below.) Much of this FF induction came from light twins. The makers of these twins (e.g., twin Comanche, seminole) wanted to reduce the height of their nacelle. Since it was on a thin wing it made sense. So Lyc came up with FF induction the airplane makers wanted. Why are there 100's of Lyc models, because of all the custom little bs they where willing to make to make them happy.

We on the other had have plenty cowl hight for a vert induction. You still have a exit (reverse) scoop sticking out below the firewall, so an induction scoop is not that much drag. The real advantage is in the example of Vans scoop-less cowl and internal Horz FAB air box. That is a little less drag. It may make a 1 mph diff. The real draw is looks. The Horz FAB air box also works surprisingly well from a pressure recovery stand point. We are splitting hair's. The Vert or Horz air box both work well.

The down side is Van's Horz FAB does not work with James Aircraft cowl, short or long. You could go with the stock cowl and highly modify it to suite you needs. That is like what I am doing, but I am making also making lots of extra work for myself.

Look at it this way, at some point the air has to make a 90 degree turn from the outside airstream and into the cylinder intake ports. So performance difference, Vert to Horz, is small, internal to the engine.


3. How valuable is a cold air sump? Worth it?

I hear up to 4-7 hp more? That is what they claim. The COLD part makes sense because you add a little more air density and gain some HP, but at expense of exhaust, airbox and maybe cowls that will not quite work together anymore, like a conventional sump? I have heard things but you need to call the sump maker and ask. Hey they may not know, they don't build airplane but they may know of the gotcha's. If you have denser air, you can make more power, you will need more fuel. Do you need an extra few HP? Look at this RV-7 cruise with a 180 HP engine is 210MPH. With a 200 HP engine it is 217 MPH. 7 MPH for 20 more HP. So 7 mph will give you may be 3 more MPH? Don't forget you need to burn more gas for that 3 mph, no free lunch. Day to day flying no big deal. Cross country race, yea sure. Those cold sumps are expensive i think. You decide. If going with a carb, the choice is made, vertical warm sump.

continued

 

[gmcjetpilot]

more more good questions

Continued


4. Value of ram air?

This topic is full of folk lore and exaggeration. Bottom line Vans FAB are pretty good and hard to improve on. There is only so much room and pressure to recover. At 175 mph you only have a tad bit more than 1 inch of mercury (Hg). If you could recover half of that, say 0.5 in-Hg you would be superman. Now there are losses inside the engine, from the throat of the crab or FI servo to the cylinder, subtract another 0.3 or 0.4 in-Hg, wild guess. So you are very happy to get 0.1 in-hg of RAM rise over ambient, may be 0.2 inch on a good day.

Most cessnas are running at over MINUS 1 in-Hg (from ambient), basically they are terriable. That is why cessna engines put into RV's run lean sometimes, we can pump more air thru them and need more fuel. Add the fact we have better exhaust, it makes it even better. It does not mean we make MORE than the rated power necessarily, only that we make rated power. A Cessna 172 with a 160 HP engine may really be getting only 140 HP to the prop. May I say Experimentals RULE.

There are no secreat formulas, and anyone saying they are getting 2" of rise is miss informed. I have heard of 0.3 or even more, like on Rockets going 240 mph. Dynamic pressure goes up exponentially with speed. So at 240 mph (indicated!) you have 2 in-hg to play with. It's the speed not the airbox however, not to discount airbox design, it is KEY. Vans has done their home work.

The other popular style airbox, especially on FF induction is the bullet design. A cone shaped K&N filter in a tube. It works very well, but there are faults stories. That cone filter does have more area, OK, so some say it is WAY BETTER. Not true. First K&N filters, cone, flat or round have SUPER low restriction at their rated flow. I mean the loss is tiny. In fact straighting the flow out has some benefits, where a filter is better than no filter.

Further, the rated flow for the filter sizes we use is more than enough. So with the filter sized properly, which Vans are w/ margin to spare, the filter is producing negligible loss. By doubling the size of the filter you may lower the loss a little, BUT HALF OF NOTHING IS NOTHING.

The air box needs volume and length or room to slow the air down, that is KEY. There is no quantum leap in scoop or airbox design, just good basics. However a FF air box is hard to do for lack of room. You have less room to slow the fast moving air and there are other compromises, they either not filtered or have no alternate air, due to room constraints.

The issue with any plane is there is no room to develop a truly high recovery scoop, may be 60% or a little higher. Theoretically 90% is possible, but not in the space we have in a light plane. Also an engine does not breath continuously. It has pulses, starts and stops!!! So you need a big airbox that has volume to act as a reservoir. The bullet design is lacking volumn, how ever it makes up some by being SPLAT on the face of the cowl. Air is going in one way or another, may be not with lots of gain but not a lot of loss either.

The prop is a bit of a problem for air flow, and people have played with making scoops angled into the realtive air flow, 1/8" from the blades for some gains, but that is odd looking. Also some gain may be lost with external drag.

Last thing, put your intake scoop far from the spinner. Right under or next to the spinner, air flow is a mess. It is like blocking the free air stream, ie the dynamic pressure. That is why the scoop on the lower part of the cowl, where Van puts it, works, its in a higher dynamic pressure area from the prop. Props make more wind further out there blade, about 2/3rds span is peachy. Near the hub, bad things happen.

This is a pet peeve of mine. I mentioned that Van's Horz FAB works pretty well. On paper it should not work as well as it does, but you can expect at least NET pressure, meaning the manifold pressure is equal to ambient in cruise. Van wrote articles and tested it thoroughly, as he always does. It is well engineered, but it is moot since it is not going on a James cowl.

That leaves the cowl chin intake cowl scoop, if designed well should be efficient and low drag. Again Van's scoop / vert FAB is a very good combo. I have one w/ some mods. I use a flex tube / duct clamped to the inside of the scoop and airbox, verses vans soft seals (that leaks). It requires a small access panel to attach the hose after the cowl is mounted. A small sacrifice for a leak free connection. However its hard to improve on Vans box overall. All the pressure recovery happens in the air BOX. It does not matter, Vert or Horz intake.





5. Your opinion, Carb vs. AFP vs. Precision Airmotive Silver Hawk vs. ECI?

I went with a Carb because the core I bought had it and switching outright would have cost me about $3000 more. FI does not mean more speed but more efficiency. Today that is a good thing and FI if purchased new may only be an extra $600-$1000 more total. So I would go FI today if buying a new engine. Call, write and read all about AFP and Precision. I made my comments about ECI's system. Even Continental, who ECI "borrowed their design from" has gone away from it and went to Bendix. Unless the ECI setup was $1000 cheaper I see no reason to go with a mechanical RPM based system. As I said, the mass air flow systems are some what altitude compensating. With the ECI, it will get real rich or rich faster as you climb, so if you are lazy and not leaning in the climb, you will waste lots of fuel.


6. Counterweighted vs. non-counterweighted parallel valve 360?

CW crank more weight, better for the prop (less or no rpm restriction) and costs more. I think only Superior offers this. There are certified parallel valve Lyc 360's (A1F6, A1G6, A1H6...) with a counterweighted cranks, but that is not what they sell new (M1B). One down side of counterweights is you can de-tune them with rapid throttle movement. Basically the weight gets slammed around and damaged. I know when flying formation, doing overhead breaks, you have to use rapid throttle movements. In formation flying you may need to Jockey the throttle a lot as well. A minor consideration but I would be less comfortable abusing a counter-weighted crank engine like that. I don't even like doing that to my non-CW 360.

7. Roller tappets or not?

email lycoming, they'll give you a scoop. It is a win-win technology wise. If buying new, it is only 500 bucks on a parallel valve w/ aerosports prices. That sounds like $500 well spent. Also looking at AeroSports prices for the IO360 (200HP) and IO390(210HP), they only show roller tappet prices for these two engines. The IO390 is cheaper by $3.6-grand? Must be Lycoming v. ECI parts. Call them. It sounds like a no brainier but I have not researched it. I know if overhauling a used engine, the case may not be suitable for a roller cam. Also I think Lyc has a corner on the market, so you have to go to them or dealers that offer Lyc parts? (Not sure about that, but I think Lyc has the exclusive on roller cam technology at this point.)
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You are welcome George, this goes into the knowledge database for the other +4000 members and countless other lurkers.

Go vertical induction (warm), short cowl and prop, life will be easy. As far as the James cowl option, its worth it IMHO. Cost a little bit more, a little more work to install but 8 mph faster. Its 8 mph faster that does not cost more gas, weight or complexity, which is even better. There are trade offs, like you can't see the top of the engine with the cowl off; you need to remove the plenum to service the top plugs. Trade offs again