Subaru Grumblings

Lots of grumbling on the Subaru boards. Summer is here, and many H-6 guys
are experiencing cooling problems. Three radiators now on some installations, driving the weight up even higher. One guy in Spain is hacked when he found the -9 he is building is going to have a 300 lb useful load with the H-6.
Funny to watch....northern customers say there are no cooling problems, guys in the south have to make partial power climbs and no touch and goes.

Airsube guys are talking about 6 ECU failures in various installations. Apparently the RV-6 crash in Idaho last year was an ECU "limp home"
failure precipitated by a sensor failure, which caused the engine to produce about 45 hp after liftoff. Partial power limp home mode can apparently be triggered when any one of a dozen or so sensors gets bad or no data.

Egg abandoned the belt drive gearbox after his off-field landing in Florida 2 weeks ago. He will now embark on his fourth generation gearbox, which will be a 2.05 to 1 ratio instead of the old 1.82. Interestingly this might cause a resurrection of the discontinued 4 cly engine on hopes that it might make advertised power on higher rpm. Weight of the H-6 also seems to be triggering a resurging interest in the four cyl motor.

I've been seeing that too..

I'm still leaning toward the H6, but I'm on the fence as to whether to go with an Egg package or roll my own. I dread solving the cooling issues. Once you get everything crammed in there, the wiggle-room for ducting design, radiator choices, plumbing, and weight shrinks pretty fast.

In defense of the Eggenfellner package, I don't think there's a better auto conversion option out there, and I'd be hard pressed to come up with something better, although given my stubbornness, I will probably try.
He has also said that there has never been a failure of a factory ECU on one of his packages. The design has also improved by leaps and bounds. On ebay last week there was a first or second gen Eggenfellner FWF package, based on the Subaru EJ22. Looking at that and comparing it to today's offering is like night and day.

The genius of Eggenfellner's design though isn't in the cooling, it's in the engine mount. The simplicity that single large plate brings to solving the whole engine-mount/psru/radiator dilemma. My guess is that he'll eventually get around to wind-tunnel testing some rad-friendly cowl designs that will become part of the package.

I really want to see the Subaru option work. I'd also really like to see any of the aerodiesel options work for less than than the price of a Lyc and a half, but I doubt we'll see that any time soon.

RV????

What are you building?

John

Baffled by decision

I was really surprised that Jan would abandon the 4 cyl to persue the H6. I understand it was due to customers wanting more power. Seems the RV9 guys all wanted the 4, but now are left with an overweight H6, or find something else. I think the 4 has potential, though I will be interested to see if he can make the HP numbers he wants. I think the package as a whole is very well done, though I am watching very curiously the developement of the new package. My opinion would have been to continue to build the 4's while working the bugs out of the H6. I don't think it was ready to market quite as soon as they were being sold. I have a couple of friends that are very interested in his equipment, but are still a little ways from making a purchase.
If you do a roll your own, don't under estimate the complexity of such a project. It can be done, and very well, but it is not a simple task. I have done a roll your own (for the most part) rotary engine, and have enjoyed it. I am readying for first engine start soon, and I don't mind saying, I knew it was going to be alot of work, but it has been more than I expected. That said, I wouldn't do it any other way if I had it to do over again.

Still Being Improved

Hot weather ops present problems for both liquid and air cooled engines in many cases if manufacturers limits are to be observed. I was flying a Grumman Tiger out of a strip at +39C a couple years ago and had to stay throttled back and climb at 200-300 fpm to keep both oil temp and CHT just below the redlines. Meanwhile we were baking as well, vainly waiting to get into cooler air.

We don't have any set limits for the Subes but I think many people are worried whenever coolant exceeds 180F and oil exceeds 210F. With non-aqueous Evans coolant (boils at 375F) and synthetic oil like Mobil 1 (5W50 now available), safe operation well in excess of these temperatures is possible and in fact proven. Despite coolant and oil temps over 230F, No Sube has failed from these causes to my knowledge.

In fact, we really want the oil temps to go over 212F in the climb at least to boil off any condensation. There seems to have been some initial reluctance to fit cowl flaps to the Sube installations to cure perceived or real high temps. Most of the people who have done this are now happier with temps in the climb and it looks like extra outlet area and/ or cowl flaps will be standard soon along with better/ bigger heat exchangers on the Egg conversions.

Generally shooting T&Gs are not a problem in even the hottest weather as during the descent, with low power, temps drop dramatically. The engine and coolant mass is able to easily absorb the heat in the short climb phase and temps stabilize in the downwind at low power. On a typical +25C day, I'll see 60-65C on the coolant on final (12-15 inches), reach 80C at the end of the climb (35 inches), 70C at the end of downwind (22 inches).

Ross,
In 4000 hrs of light plane flying I have never pulled the power back in climb for temperature problems. Wrong thing to do anyway, because the extremely rich mixtue at WOT provides greater cooling due to rich mixture. I have lowered the nose for a shallower climb, to increase cooling.

Search the Egg group for Dave Dormeier's posts and you will see that what you are saying about the H6 is inaccurate.

I lowered the nose on the Tiger for 105 knots at WOT and the the temps still edged past the red so I pulled power back about 150 rpm (still full rich) and maintained about 95-100 knots IAS. The temps settled against the redlines. Just reporting what I saw on this aircraft. A Tiger doesn't climb well at these temps, airspeed and near gross.

I was not referring to Egg's H6 in my post but rather my Sube/ 6A which has very extensive temperature and pressure instrumentation and about 350 T&Gs on it. I'm on all the Sube lists every day and very familiar with the concerns in this area.

we are building Experimental aircraft...

Dave has one of the earliest H6's and hasn't made the cowl changes others have done to get better cooling. He hasn't found it worth the hassle (yet anyway). Look at Tom Moore's posts and you'll see that with a little work, the cooling can be managed. It's a constantly changing environment, and every installation is different right now, so it's not surprising that there are a variety of experiences reported.
If you're willing to experiment a bit, he's the best game in town. If not, stick with a Lycoming. Everyone gets to make the choice.
Subaru's don't pour in extra fuel at WOT, so you can't always use the same procedures to operate them as you do for a Lycoming.
Jan Eggenfeller is constantly working to improve his engine packages, and everyone of course has opinions on what he should do. Not every idea will pan out, and he doesn't please everyone all the time. But overall, his engines work well and are gettng better with every generation. Quite a few folks flying Jan's engines are very happy with them - you just don't hear as much from them (probably because they're too busy flying).
I've got an H6 on order for delivery in August...

Subaru Growing Pains

Dennis,

Since Egg is selling FWF installations, I would think they would cool a little better than they do. Seems like a little warm weather testing would be in order before selling a new engine package.

The problem I have with Egg (I was almost a customer) is that his developement process is not transparent. Up until the day he discontinued the 4 cylinder engine he insisted there was no performance problem with it.
Now that it isn't being sold anymore, he alludes to performance shortfalls, and is now talking about the new gearbox (no, the new, new gearbox) curing the low power and torque issues with the 2.5L. (This is the only engine I know of that can't spin a fixed pitch prop, oh yea, and the H6).

The same goes for the cooling issues. Jan and his legion of followers steadfastly denied cooling problems on the H-6 right up to the day that photos of the 3 radiator configuration appeared on the website.
Up until recently, any hint of technical problems have been sterilized from the website, preventing anyone considering his motor from knowing about the cooling and weight problems. He is permitting more information flow lately, but he also threatened to shut the website down completely last week, presumably because of the abuse he has been taking about power, weight and cooling issues as of late.

I hope your H6 works out to your satisfaction. I'm sure more cooling work will continue to lower temperatures, but cooling drag will continue to make them less efficient than Lycoming installations. The new gearbox (2.05) might even allow for the use of a fixed pitch prop.

Speaking of new gearboxes and transparency, supposedly the belt drive gearbox plane (Tom Moore's) was brought down by a piece of metal accidentally left in the cowl. With no further explaination, the gearbox was abandonded a week after the engine failure, with no mention as of why.
If I was one of those 15 guys waiting for a RV-10 installation, I would be pissed.

And lets not forget weight. It's a crying shame that H6's are being installed on RV-9's and thus rendering them single seat arcraft, if flown to Van's certification weights. One of these days, Van and/or the FAA is going to put a stop to the senseless powerplant latitude afforded homebuilders. Van is a masterful engineer and kit developer, so I don't understand why people are trying so hard to invalidate his good work. If Van thoght his aircraft could or should be flown at 2000 pounds, I'm sure he would have spec'd them out at a higher weight.

Sorry Dennis that this got so long, but I feel real strongly about these issues.

Decide intelligently

When you are evaluating everything regarding your engine choice, do it intelligently. When you carefully evaluate the pros and cons of alternative engines the disadvantages will far outweigh the advantages. Even with careful evaluation people will let their emotions get the best of them and they get the alternative engine anyway.

Please understand, I was a former victim of a Subaru engine company. I was mislead, lied to and lead down a path. This resulted a financial loss and probably a year and a half of delay in flying the project. That is all I'm going to say on the subject of this company, so don't ask.

The alternative engine packages have cooling issues. This is always glossed over. You will be told there is no problem. There are at least two people in AZ that will be changing out their Subarus for a "real" engine when they can afford it. Two that I am personally aware, of are having significant cooling issues and not getting anywhere close to the performance expected.

Bottomline, if you enjoy working on engines, R&D work and tinkering buy the alternative engine. If you enjoy flying buy a Lycoming or one of the many fine clones that are out there. I personally went with an ECI IO360 built by Robbie Attaway (www.attawayair.com). I now have 85 hours on the plane and fly as much as I want to. The performance has been fabulous with no problems at all. Keep in mind I live in AZ with probably the most challenging heat issues in the US. I can climb out mid day (105 degrees) and have my #4 cylinder reach 420 for a short time at 600 ft per minute. If I back off to 400 ft per minute it will be around 400. I seriously doubt you could fly a Subaru powered plane in this heat after 8 in the morning here.

For those of you contemplating an alternative engine look at the weight issues and the number of incidents per hour flown. Now ask yourself if you are willing to put a family member behind that engine. Your answer should be no.

There is intense loyalty to the one major company. That loyalty, I believe and has been demonstrated, to create excuses and less than factual accounts of "what really happened," when an incident occurs.

Hate to rain on the alternative parade but I enjoy flying too much spend time messing around with something that is simply doesn't have the hours behind it to prove dependability.

Senseless latitude?

Yukon said:

... One of these days, Van and/or the FAA is going to put a stop to the senseless powerplant latitude afforded homebuilders.

Click to expand...

John, I'm happy that the FAA does not agree with you on this point. "Senseless powerplant latitude"? If you want a certified aircraft, there are a lot on the market. Some people like to experiment. More power to them, and I'd say everyone benefits. If you want to build it exactly as Van's suggests, there is nothing keeping you from doing it, and no one will criticize you. I'm not sure why you are so concerned about others using non-lycoming engines.

Van is a masterful engineer and kit developer, so I don't understand why people are trying so hard to invalidate his good work.

Click to expand...

Van is an outstanding engineer and businessman. He has the utmost respect in this industry, and I personally can't say enough good things about him. It has been an honor for me to meet and talk to him.

Installing a non-lycoming engine in one of his kits does not invalidate his good work in any way. Neither does the fine work that John Harmon or Mark Frederick have done modifying his designs to create the two flavors of Rocket. This is what progress is all about, standing on the shoulders of giants.

I shudder to think what experimental aviation would be like if the government were to restrict our "senseless latitude".

Let's all try to be constructive in our critisim. I'm sure we can find grumbling in just about every aspect of experimental aircraft. Without experimentation, EAA and homebuilding would be nonexistent. One (wo)man's pleasure is another (wo)man's poison. Because we are so diverse in our ideas is what makes this forum so rich with ideas.

Roberta

Sensible Engines

Mickey,

How bad would it be if builders were required to comply with the limitations designers intended for the kits they were selling? I'm not saying that alternatives be excluded......I'm saying that installations that are so heavy as to put the aircraft out of it's intended weight limitations be restricted.

Your RV-8 can handle the extra weight of the H6, but do you think that it is a sensible engine for the RV-9? How about the fellow here in Phoenix that installed a Corvette V8, with air conditioning, in an RV-6? Is that sensible? It is also a single seat airplane now, one capable of level flight speeds in excess of red line. Is that a sensible or responsible use of Van's design? Sure this is "expermental" aviation, but why should experimentation be foolhardy. An experiment should lead to a useful outcome, not single-seaters.

Nose struts on all Van's airplanes have shown themselves to be barely adequate if not somewhat marginal. What's a heavy engine going to do to this problem. Does Egg include a titanium nose strut to support that H6?

I'm not exactly making this stuff up, Mickey. Didn't you see Van's article about heavy weight kit mods in the last Rviator? These are Van's opinions, not just mine.

Mickey, if you want to shudder, I mean really shudder, think of the possibility of RV's being uninsurable. It is a very real possibility if these things keep stacking in 3-5 per week around the country. Can any successful individual afford this risky hobby without a liability umbrella????

I'm not sure about the FAA, but how exactly would Van stop people from putting alternative motors on their planes? I mean, under existing regs I'm pretty sure I can scratch build an airplane using bamboo and bailing wire as long as I can get a DAR to sign the papers. I could use Van's ideas/parts mixed with my own and power the thing with a giant twisted rubber band if that's what I want to do. This is exactly as it should be. If some guy thinks he needs a flying Corvette why should I care?

Keep in mind that the RV1 was somebody else's design that Van modified in the biggest way of all: a completely different wing. I'll bet a lot of Playboy fans thought this was blasphemy at the time, but it all worked out just fine.

P.S.

Doug,
I just found out that the automatic dirty word catcher doesn't like the name of the designer of the above-mentioned plane, but allows the type name in spite of the fact that it has the same name as a nudie mag. Oh, the irony.

Big engines

Yukon said:

How bad would it be if builders were required to comply with the limitations designers intended for the kits they were selling? I'm not saying that alternatives be excluded......I'm saying that installations that are so heavy as to put the aircraft out of it's intended weight limitations be restricted.

Click to expand...

I think this would be terrible, and would stifle innovation.

Yukon said:

Your RV-8 can handle the extra weight of the H6, but do you think that it is a sensible engine for the RV-9? How about the fellow here in Phoenix that installed a Corvette V8, with air conditioning, in an RV-6? Is that sensible? It is also a single seat airplane now, one capable of level flight speeds in excess of red line. Is that a sensible or responsible use of Van's design? Sure this is "expermental" aviation, but why should experimentation be foolhardy. An experiment should lead to a useful outcome, not single-seaters.

Click to expand...

I don't want anyone enforcing their idea of "sensible" on me, and I certainly wouldn't try to enforce my idea of "sensible" on them.

Yukon said:

Nose struts on all Van's airplanes have shown themselves to be barely adequate if not somewhat marginal. What's a heavy engine going to do to this problem. Does Egg include a titanium nose strut to support that H6?

Click to expand...

This is one of the many things the builder needs to take into consideration when installing any equipment that is not specified by the designer. It's the same when someone adds an autopilot, or long range fuel tanks, or soundproofing in the cabin, or an EFIS in the panel. This is all part of experimentation.

Yukon said:

I'm not exactly making this stuff up, Mickey. Didn't you see Van's article about heavy weight kit mods in the last Rviator? These are Van's opinions, not just mine.

Click to expand...

Yes, I read the article, and I agree with Van's points. If someone wants to add an engine that is 100 or 200 lbs heavier than the one Van's recommends, who am I to say that they can't do this? The builders know that they have 100lbs less useful load if they want to stay within Van's MTOW, and they know that they have less structural safety margin if they decide to exceed the recommended MTOW.

Yukon said:

Mickey, if you want to shudder, I mean really shudder, think of the possibility of RV's being uninsurable. It is a very real possibility if these things keep stacking in 3-5 per week around the country. Can any successful individual afford this risky hobby without a liability umbrella????

Click to expand...

Wow - there's a lot to address in those comments!

Insurance is a private contract, and many builders don't get insurance even though it is available. Many activities in life are not insurable at a "reasonable" price. I don't believe the government should step in and regulate those activities to reduce their risk enough to be insurable.

New RVs are being completed at the rate of about 3-5 per week, but I believe accidents are much less frequent. Perhaps there are some accidents that do not show up in the FAA/NTSB databases. Even still, how many of these accidents involve an aircraft with systems that Van's doesn't recommend? How many of those that do, had that system as a cause of the accident? Very few, based on my readings of the NTSB reports.

If Van's begins to feel that alternative engines are causing a blemish on his reputation, he can require the purchase of an engine with his kit. Some other kit sellers do this. I think it is a bad idea, but that option is available to him. If insurance companies feel that alternative engines are too risky to ensure, then they will stop offering insurance for them, or increase the price. This is their right as independent business people. What I strongly oppose is to have the government step in to try to tell us what is sensible or not.

Read It Again Mickey

Mickey,

You are not making any sense at all. If Van's is unhappy with the current trend in overweight airplanes, why do you keep trying to rationalize the practice. You can't say how much you respect Van one minute, then disregard his judgement the next. I suggest you read Van's article again,
because you obviously missed his intent.

Aren't you in the UK? Aren't their certification standards even stiffer than US?

Buyer Beware

Also, Mickey, even if the Feds or Van's choose to make no changes in the system, the marketplace will ultimately strangle a marginal product. A heavy
and hot motor will be soon be rejected by the buying public. Look at the websites and you will see that this process has already begun.

Marketplace

Yukon said:

Also, Mickey, even if the Feds or Van's choose to make no changes in the system, the marketplace will ultimately strangle a marginal product. A heavy and hot motor will be soon be rejected by the buying public. Look at the websites and you will see that this process has already begun.

Click to expand...

And this is the way it should be. If the product works, people will buy it. If it doesn't, the company has to change the product or it will go out of business. This is capitalism at its finest. Seems to be working well for most of the world.

Rationalization

Yukon said:

You are not making any sense at all. If Van's is unhappy with the current trend in overweight airplanes, why do you keep trying to rationalize the practice. You can't say how much you respect Van one minute, then disregard his judgement the next. I suggest you read Van's article again,
because you obviously missed his intent.

Click to expand...

Sorry my posts are not clear. Perhaps my passion for the topic is clouding my writing. I'm not trying to rationalize anything, except the builder's freedom to chose what they do with their experimental airplane. There are many things I personally don't condone, but do not feel I have the right to restrict others from doing. I would never burn the US flag, but I would give my life in combat so that others have the right to do so.

Yukon said:

Aren't you in the UK? Aren't their certification standards even stiffer than US?

Click to expand...

The UK has much more restrictive rules for building kit aircraft. They don't have an experimental category. I'm in Switzerland, where they do have an experimental category, but the rules are more restrictive. However, I don't want the rules in the US to be like they are in most other places in the world, since when I get back I want to still have the freedom to put a cummings diesel in an RV-12 if I feel like it!

I don?t think Vans were criticising so called overweight engines but rather were talking about builders declaring an increased gross weight.

How the gross weight is made up I would suggest is the prerogative of the builder.

So if you choose to have extra paint, more instruments or a heavier engine it?s up to you. If the heavier engine require a lump of lead in the tail ? up to you! If the work you do results in a plane that can only take one person and be under the gross weight declared by the designer that is up to you too. Maybe the builder wants lots of toys, a full upholstered interior, extra fuel and is willing to accept the limitations that this will bring ? fine ? their choice.

What?s the big deal? As Mickey suggests where is the evidence that it is the non standard installations that are causing accidents. Is it only heavier engined planes that have suffered nose gear failure, or is it planes built to the designers? standards and recommendations.

And if the ?Feds or Vans? change the rules and it impacts the market ? like for example all the non TSO?d avionics suppliers as well as the other suppliers to the experimental market, or if a product is ultimately no good for the application then yes it will fall by the wayside. Yes absolutely buyer beware!

I tend to agree with Mickey?s position, and I can absolutely see how you can on one hand respect someone, or a company, and on the other disagree with if not disregard the judgement of the same. For example how many people on this board have openly criticised the nose gear on the 7A, when Vans have time and time again backed their design.

Back to the original subject of the post, the Egg FWF packages. Certainly successful for some but frankly I think with Egg you are joining a development program. Nothing wrong with that but go in with your eyes wide open.

Peter

Van's has never been happy about people building his designs heavy but has changed his designs to suit the new market because most people were hanging a 360/ C/S Hartzell on every design anyway. They came out with the 7A with a gross 150 lbs. higher than the 6A to allow a reasonable useful load for all the bells and whistles the vast majority were installing. The structure is very similar between the two. How many a/c are built with an O-320 and wooden prop and come out at 985 lbs. these days like Van's prototype 6A?

The growing trend even on the -9 is to fit a 360/ C/S and cram the panel. It is clear that many builders don't share the same philosophy as the factory and that the factory has had to change along with the market to some degree. At least with the RV10, they just hung the 540 on to begin with although it wasn't long before people were asking if a 300 hp version or a turbo version could be used. Maybe Van's should create an O-720 version.

There is no doubt that lighter aircraft perform better in every way and I think all builders should understand that. If you want to do aerobatics with 2 on board, you better build it light to be legal and safe. If you are flying essentially straight and level like most RV pilots, a 1800 lb. RV is not going to come apart if you fly it by the numbers and avoid doing 5G carrier landings.
I don't think there have been any structural failures on 6s-10s when all the parts are there, assembled correctly and flown by Van's published numbers so there is little evidence to support that this is "dangerous"."

Unfortunately many people don't fly by the numbers and do foolish things and there is little that anyone can do about that except more education possibly. If you are yanking and banking over the recommended weights and speeds, it may well kill you some day. Van's knows what they are talking about, they designed the aircraft and had the unfortunate and sad lesson driven home in the loss of their RV-8 in 1998. Please learn from these tragedies.

When it comes to alternate engines, all of the ones that have flown to date have weighed more than the equivalent Lycoming. Depending on the redrive and propeller used and the distribution of masses firewall forward, the empty C of G may be more or less forward than a 360/ C/S combo. Correction of this within recommended limits by the movement of the battery or radiators or sometimes ballast is not rocket science. Just so that people are clear, installing any of the currently popular Subaru or Wankel engines into RV6-RV9 airframes WILL result in a heavier aircraft. Mickey was kind enough to direct us to a database on RV weights on another forum which supports this fact.
http://www.rvproject.com/wab/

We have no stats to know what the accident rate per flight hour is like on alternative vs. Lyco powered RVs. The only way to improve alternative engine installations is to fly them and share the information and experiences. I'm glad that experimental aviation still gives us that lattitude.

rv6ejguy said:

Van's has never been happy about people building his designs heavy but has changed his designs to suit the new market because most people were hanging a 360/ C/S Hartzell on every design anyway. They came out with the 7A with a gross 150 lbs. higher than the 6A to allow a reasonable useful load for all the bells and whistles the vast majority were installing. The structure is very similar between the two. How many a/c are built with an O-320 and wooden prop and come out at 985 lbs. these days like Van's prototype 6A?

Click to expand...

rv6ejguy said:

Ross, do you really think Van determines aircraft specifications of new designs based on the non-compliance of his builders? The RV-7 has 2 more feet of wing and 10 percent more wing area. In other words, it is a BIGGER
airplane and hence, a gross weight increase, with a corresponding increased wing root and centersection strength.

Van does appear to be wising up with the RV-12. With the help of LSA rules, I believe he is making the Rotax the only engine that can be used.
Good thing, too, because LSA is going to bring out lots of low buck'ers, many anxious to test their lawn tractor's engine in their new airplane to save a little coin. The Rotax is reliable, but quite expensive, but will be mandated
under the more stringent LSA rules.

Time will tell, Ross, if the WankenSubes prevail. Lots of defunct auto converters go ahead of them. Their chances of survival will be much better though, if they allow the builder to comply with design specs.

Click to expand...

Yukon said:

Ross, do you really think Van determines aircraft specifications of new designs based on the non-compliance of his builders?

Click to expand...

sometimes

http://www.vansairforce.com/community/showpost.php?p=48738&postcount=48

LSA is much different....there are very strict rules, and you have to bring the plane in under a certain weight, etc etc etc. The rules governing the form and function of an LSA forces you to make design compromises. Things become much easier when you design around a specific engine...you know all the loads, fuel flows, structures get lighter, etc.

I'm certain the intent wasn't to "lock" anyone into to using one particular engine althought like anything, the path of least resistance is to just go with all the manufacturers recommendations.

Ross, do you really think Van determines aircraft specifications of new designs based on the non-compliance of his builders? The RV-7 has 2 more feet of wing and 10 percent more wing area. In other words, it is a BIGGER
airplane and hence, a gross weight increase, with a corresponding increased wing root and centersection strength.

Click to expand...

John...

Here is a quote from Sport Aviation...April 2001...page 39 & 40. This is the introductory article on the RV-7(A). The person being quoted is Dick VanGrunsven:

" 'We're trying to develop an airplane that has a designed and tested (italics their's) gross weight more in line with what they [builders] are going to do anyway.' "

"The same goes for powerplants. 'People always want bigger engines, and a number of people were putting bigger engines on the -6 despite our recommendations,' Van said, noting that the -6 is designed and tested for 150 - 180-hp engines. 'Knowing people wanted this, we designed the airplane for a bigger engine (up to 200 hp), not just a hot rod airplane.....' "

Bottom line...Van designed the -7 parameters partly in response to builder's powerplant choices.

Dan

LSA

No, John , LSA recognizes the value of an aircraft designer specifying how the plane is designed and built. Engine selection is part and parcel of the design process, making alternative engines unusable in an LSA certification.
The Rotax will be the one and only engine permitted in the RV-12 because the government recognizes the value of professional design guidance, and mandates it.

Designed and Tested

djvdb63 said:

John...

Here is a quote from Sport Aviation...April 2001...page 39 & 40. This is the introductory article on the RV-7(A). The person being quoted is Dick VanGrunsven:

' "We're trying to develop an airplane that has a designed and tested (italics their's) gross weight more in line with what they [builders] are going to do anyway." '

'The same goes for powerplants. "People always want bigger engines, and a number of people were putting bigger engines on the -6 despiter our recommendations," Van said, noting that the -6 is designed and tested for 150 - 180-hp engines. "Knowing people wanted this, we designed the airplane for a bigger engine (up to 200 hp), not just a hot rod airplane....." '

Bottom line...Van designed the -7 parameters partly in response to builder's powerplant choices.

Dan

Click to expand...

Dan,

The key issue here is the RV-7 was designed and tested for larger engines and heavier weights. Stronger airplane, bigger engine, higher weights. It bears no resemblance to an RV-6 with a V-8, or a 9 with an H6.

Yukon said:

No, John , LSA recognizes the value of an aircraft designer specifying how the plane is designed and built. Engine selection is part and parcel of the design process, making alternative engines unusable in an LSA certification.
The Rotax will be the one and only engine permitted in the RV-12 because the government recognizes the value of professional design guidance, and mandates it.

Click to expand...

Fact is, under the regs, you can put anything you want to in the RV-12, as long as it meets the required weight/speed parameters. I can put a Harley Davidson 2 cylinder in my RV-12 as long as I comply with the speed/weight, and Van's can't do a darned thing about it.

PJ

Van's Website

PJSeipel said:

Fact is, under the regs, you can put anything you want to in the RV-12, as long as it meets the required weight/speed parameters. I can put a Harley Davidson 2 cylinder in my RV-12 as long as I comply with the speed/weight, and Van's can't do a darned thing about it.

PJ

Click to expand...

That's not what the Van's website says.

There are likely hundreds of 6As out there flying thousands of hours per year at weights over 1650 lbs. pulling 2-3 Gs without crashing and burning. This is no more dangerous than a 6A at legal aerobatic weight pulling 4-5Gs.

It's clear that within total structural loading and speeds, RVs are very safe and robust.

As far as performance and feel goes, every airplane I've flown handles and performs better with just me and light fuel on board- no surprise there. The 6A with its low aspect ratio wing fairs worse than many other designs but even flying mine at 1750 lbs., it outperforms most other production designs handily.

RV12s will be fitted with other engines besides the Rotax, you can count on that just as every other Vans design has been to date.

Historically, RV6-8s haven't broken at the center section, they have failed outboard of the flap or at the stab. The 6 with shorter span, many more fasteners spreading out the loads and butted spars may in fact be stronger than the later designs.

I doubt if rotary engines or Subes will prevail over Lycos even 10 years from now. The only trend is that more alternatives are being fitted than ever before. I think most people going into alternatives know that the aircraft will be heavier and may have less useful load. Certainly not a big deal for many who fly mostly solo and or short trips with light baggage. For many, other advantages outweigh the weigh issue. Reading the latest Kitplanes with the owner of the Egg powered Glastar sums it up well. Burns NO oil, leaks NO oil, 500 hours between plug changes, smooth, economical. Best engine he has ever flown and he's built 7 planes and owned 22. Cost him $14,500.

Yukon stated:

The Rotax will be the one and only engine permitted in the RV-12 because the government recognizes the value of professional design guidance, and mandates it.

Click to expand...

This is not necessarily true. There are three possible scenarios wherein the RV-12 could be marketed. Vans website poses these possibilities per the quote below:

Depending on what we learn from this airplane, we may decide to proceed with a kit airplane. The most probable first step would be a kit similar to our current "49%" kits. Finished airplanes would be registered in the current Experimental category. (If the airplane meets the performance standards for an LSA airplane, it can be flown by anyone holding a Light Sport pilot?s license, no matter what category it is registered in.)

After that, we may consider a Special LSA kit. This category allows kits to be completed to far more than 49%, which sounds attractive. But the flip side is that no modifications or variations from the plans are permitted. Every example must be built to the manufacturer?s compliance standard.

The possibility of a fly-away airplane (permitted by the standards of the category) is so remote that we can?t even discuss it at this time.

Click to expand...

So, if we build an 49% RV-12 kit and certificate it as an experimental (almost certainly the way the plane will first be offered) then we have the legal option of installing any engine we want (personally, I would follow Vans's advice and use the 912). The plane could then be flown by a pilot operating under Light Sport rules as long as it meets weight/speed regulations. Whether or not a non-912 powered RV-12 will be insurable is another question.....

Only if the RV-12 is offered as a Special LSA kit will the builder be obligated to install the 912 if the plane is to be certificated as an LSA craft (hmmmmm.....can a Special LSA kit be certificated as experimental, powered by a non-912 and flown by a pilot with higher than Sport Pilot priviledges??? I suspect some will even though it won't meet the letter of the law due to the +51% kit thing...). And if Vans offers the plane as a turn-key SLSA aircraft, it no doubt will be powered by the 912.

I suspect Vans is going to have a run-away-best seller regardless of which way the RV-12 is marketed (especially as an experimental kit).

John(Yukon), somehow in the posting/editing of my reply to your post, your signature appeared under my reply, then when I tried to edit the post, your original message disappeared! Don't know how it happened, but sorry for the confusion. Your original message appears in the quote box, no censorship intended.

Sam Buchanan

====================

The last RVator article and website update generated more discussion of the RV-12 on the web and sure enough, several people chimed in, wondering about alternative engines. Why not a BMW engine, a Suzuki engine, an older Subaru engine? Amusing. We finally choose an engine other than a Lycoming or a Continental and immediately people start speculating about using something else.

Sam,
This is the quote from Van's RV-12 website that leads me to believe the Rotax will eventally be the required engine. If it is offered as an experimental certification, there will be the opportunity to over-engine it, although the weight and stall speed standards still apply.

Click to expand...

As stated in my earlier post, the 912 can only be the "required" engine if the RV-12 is offed as a Special LSA kit or a flying SLSA aircraft. If the RV-12 is offered as an experimental kit (extremely likely) then the FARS (but not necessarily insurers) will allow the builder to use any engine he/she wishes.

You stated that this will create an "opportunity to over-engine it". I prefer to be more optimistic and offer that it will also offer an opportunity for a builder to use an alternative engine of the proper weight and power.

The only way Van can offer the RV-12 as a "Light-Sport kit" is to first certify it as an "S-LSA" (factory built). I really don't think he intends to do this. Other than that, the only other option is to offer a 51% amateur-built kit that if built to plans will meet Light-Sport parameters and can be flown by Sport Pilots. This aircraft would be subject to exactly the same rules as any other amateur-built aircraft.
I was one of the first DARs authorized for LSA and have certified over 30 such aircraft, both E-LSA and S-LSA.

Yukon,as far as I know the crash in Idaho was caused by using the wrong prop pitch for take off.I understand this because I am the only other person with that sme engine in an RV .the pilot did not do a full power run up to check prop pitch and get full power for take of.I now have 250 hrs on that same engine in one yr at oat from +98 deg to-30 not a single skip.Sorry but an absolutly incredable engine pac.

Oh yea, and I had 3 engine failures and ......

rv6ejguy said:

Reading the latest Kitplanes with the owner of the Egg powered Glastar sums it up well. Burns NO oil, leaks NO oil, 500 hours between plug changes, smooth, economical. Best engine he has ever flown and he's built 7 planes and owned 22. Cost him $14,500.

Click to expand...

Reading the same article, I got something different out of it. The article you refrence featured several Gentleman's alternative engine experience, besides the happy Glastar owners comments. I was a little shocked at how many there where of the group that had engine failures; one Guy had multiple engine failures! He wrote "After the second failure I decided to install a different alternative engine" or something like that.

I did like the article. For a 75HP engine the old overhead valve Subaru 1.8L and even better the VW are interesting, but this is not new. Revmaster and Great Planes have been improving the VW engine for aircraft use for decades. Also there are little homebuilt's designed around the VW: KR-2, Quickie , Dragonflys, Hummel Bird (1/2 of a VW)

This begs the question, why are there not 1000's of VW powered KR-2's or Quickies flying around? There are many 1000's of RV's with Lycoming's flying. I am just saying, you can't argue with success. The point is build and fly the engine designed for the airframe or at least one which is a good match. The latter criterion, "good match", is subject to debate (you think ).

I don't want a 75 HP plane; I want a 180 HP RV.

In the 115-300 HP range, especially 150-200 HP engine category, the Lycoming just keeps being the epitome or standard that all others are judged. That's not a slight towards the Japanese engines, but it's a tribute to Yankee ingenuity, even if it's +50 years old. I know some what to make it about oil use or leaks or something, but my Lycoming uses a little over a Qt. between 25 hour changes and leaks no appreciable oil. It may be a valid point for the Subaru but a small one, and it does not apply to the Rotary which burns oil by design. As far as moving a mixture control knob once, twice may be three times during a flight, ho hummmm.

I can tell that it's a bitter pill to swallow for some technophile's. I also love technology, ECU's and all, but sometimes 20th century Farm Tractor technology works best. Listen to this, Nuf said:
http://www.alexisparkinn.com/photogallery/Videos/Radial.wav ( a lycoming of sorts)
or
http://www.alexisparkinn.com/photogallery/Videos/R4360Starting.wav

Yukon said:

Also, Mickey, even if the Feds or Van's choose to make no changes in the system, the marketplace will ultimately strangle a marginal product. A heavy
and hot motor will be soon be rejected by the buying public. Look at the websites and you will see that this process has already begun.

Click to expand...

John, doesn't this statement fly in the face of your belief that "One of these days, Van and/or the FAA is going to put a stop to the senseless powerplant latitude afforded homebuilders"? Your statement about the marketplace implies that you believe a heavy hot motor will be rejected by the buying public. If that is so, then why would you ever want the FAA to get involved in the decision. This is capitalism at its perfect form. If the product is no good the public will reject it. If you believe this is what is to come of these type of engine installations then why do you sound so angry that people are "experimenting" with their experimental airplanes? If the market will eventually weed out the chafe from the wheat why are you so bent out of shape about all of this? Why in the world would you or anyone else ever think that MORE government involvment in our lives is a good thing?

Yukon said:

No, John , LSA recognizes the value of an aircraft designer specifying how the plane is designed and built. Engine selection is part and parcel of the design process, making alternative engines unusable in an LSA certification.
The Rotax will be the one and only engine permitted in the RV-12 because the government recognizes the value of professional design guidance, and mandates it.

Click to expand...

The RV-12 LSA, if built with the LSA designation and sold as a ready to fly LSA will have a specific engine because it is spelled out to be so in the LSA rules. An LSA airplane will be a certificated airplane and the LSA rules require specific requirements in this regard. If Vans sells an ELSA (Experimental Light Sport Aircraft) version of the RV-12 the builder of the airplane will have the same latitude to choose as he currently does in choosing what engine to place in the airplane. As long as the airplane meets the strict requirements of weight, speed, stall, etc for the LSA then the builder's choice of engine is irrelevant to the process of certifying the ELSA.

John, I wonder why you have such strong feelings about others building airplanes differently than you think they should be doing. You have made statements about others not "respecting" Vans if they do not follow his designs to the letter when building. I am getting a feeling that you are having a hard time "respecting" other builders who do not believe in the same manner you do. I truly hope that is not the case. You sound like a man of intelligence and knowledge that all of us can learn from but if learning from you is at the expense of curtailing my inquisitive nature and desire for experimental freedom I am not sure I could learn very well from your wisdom. I would welcome the opportunity to be proven wrong in my thoughts on this.

Responsible mods

Yes Steve, I think you are right, ELSA will give some engine latitude to the builder. However, I think the maximum gross weight number is going to prohibit builders from "experimenting" with inappropriately heavy engines.

I think experimenting is great Steve, when it is thoughtful, creative and productive. I respect anyone so engaged. Doing otherwise jepardizes the
safety and long term viability of our sport.

Yukon said:

I think the maximum gross weight number is going to prohibit builders from "experimenting" with inappropriately heavy engines.

Click to expand...

I agree with you on this. Which has more to do with why I think more builders will go with Van's ideas of placing the 912 in it more so than any other reason. The truth of the matter is that there are very few options that allow for the performance at the weight the 912 has to offer. I am sure builders will try, but unless something new comes out on the market with comparable performance to compete with Rotax, the 912 may be the best choice if not the only choice.

Steve,

LSA is the first complete airworthiness reg written by the Fed's in a long time.
I don't know exactly, but I think our regs were written when all engines were marginal, and there weren't lawyers and politicans on every street corner.

If they are trying to restrict weight and engine choices in LSA, I'll bet they carry that thinking into experimental if guy's in our sport continue to show questionable judgement.

I suspect Vans selected the Rotax for several reasons- it is available and proven although expensive, it provides good power to weight, and probably most importantly, its power is limited which makes increasing cruise speeds above the 140 limit difficult.

FWIW, from the data Ive seen, the best "value" motor for the RV12 just might be the Suzuki supercharged (metro?) engine- one of the very few automotive engines designed to run continually at high engine speeds.

Hey Yukon, what's with the P&W R2800 in your sig? Radial RV in your future? That'd be one heck of an "alternative"!

Just curious...

John,

"However, I think the maximum gross weight number is going to prohibit builders from "experimenting" with inappropriately heavy engines."

I love your engine in your signature block------------now that will make a -9 sit up and take notice

Cowling it might be a bit tough------------------

Mike

If they are trying to restrict weight and engine choices in LSA, I'll bet they carry that thinking into experimental if guy's in our sport continue to show questionable judgement.

Click to expand...

The restriction on weight and speed in LSA is not due to concern about questionable judgment on the part of light sport pilots, but rather to limit the size and performance of the aircraft. The real world has proved that it is impossible to legislate away people's capacity to exercise questionable judgment, otherwise we would never see pilots flying VFR into IMC.

Who knows what the FAA and other powers that be will attempt via regulations in the future, but I suspect if the brakes are applied to "experimentation", it will be at the hands of insurance carriers.

Questionable judgement

Yukon said:

If they are trying to restrict weight and engine choices in LSA, I'll bet they carry that thinking into experimental if guy's in our sport continue to show questionable judgement.

Click to expand...

John, do you have any examples of judgement you believe to be questionable? As I mentioned earlier, I'm not able to find any information that shows that experimental aircraft are experiencing more accidents or incidents with increased MTOW or engine choices. Perhaps you have other sources of information.

FWIW, from the data Ive seen, the best "value" motor for the RV12 just might be the Suzuki supercharged (metro?) engine- one of the very few automotive engines designed to run continually at high engine speeds.

Well, three cylinder, turbo charged weighs 159 LBS without radiator or coolant, and only provides 80 HP.

http://www.raven-rotor.com/html/redrive.html

Compared to the rotax which provides 100HP with no turbocharger at weighs 140.6 HP installed, with rads and coolant.

http://www.kodiakbs.com/engines/4sw.htm

Prices seem to vary but without coolant systems seem to be in the $7K range. So, plus a few quality rads, plus mount and other fabrication, and the new cowl necessitated by packaging of the geo engine, I am not sure where the value is.

It appears the only way to get into the 100hp level is to go with a four cylinder model which makes sence because 100 HP per liter is a pretty high specific output, and may not be the best idea in an aircraft.

Ask Van

Mickey,

I think you should ask Van that question. I'm sure he had his reasons for writing that article. The only numbers I'm familiar with is that experimentals have 300-400% higher accident rate than certificated aircraft.

Jconard,
Thanks for the update- last I heard (~a year ago) the supercharged Suzuki output was listed a bit higher, in the 130 hp range, which made it competetive with the turbocharged 914.

Search the Egg group for Dave Dormeier's posts and you will see that what you are saying about the H6 is inaccurate.[/QUOTE]

John,
Perhaps a word or two from the horses mouth would clarify this matter.

First off, I am with the H6 because it has a chain timing drive and a metal cover over it. The extra power is nice for take off, but the prime reason for the switch for me is the timing drive difference.

My original H4 had the super charger belt jump its pulley, penetrate the plastic cover over the belt timing drive and shut the engine down in about 2 seconds. The off field landing resulted in a flip and about 6 months of work to repair the airplane. The original H4 with a Quinti prop performed very well with the RV-7A.

There are heat issues with the H6 primarily because my early engine is running with the same radiators as the H4. But it is not an impossible issue. I have flown in very warm temps and never not flown because of those uncomfortable circumstances. To illistrate, the day I checked out John Goodman prior to his first RV-9A H6 flight, the surface temp was 93 and we got an hour of flight time in with 3 take offs and landings before the engine heat soaked and needed an hour of down time to cool off. As we speak, I am installing the Gary Newsted radiator box to cowl panels. They will help for sure.

This certainly is no worse than my experience with Lycoming. I've had a LEZ with an 0235 and a Cozy with an 0360. Both would have required special technique to keep the oil temp below the red line on warm days I fly the H6.

Another item, for those sitting on the fence, is fuel. I burn 97 octane, 93 octane, 87 octane or if need be, 100LL. The Subby doesn't seem to care, but of course its fuel of choice is mogas. Vapor pressure must be checked with mogas and the flight flown according to the limits of the fuel.

dd
RV-7A H6
N707DD

Thanks

David,

Thanks for the input. I too built a Long-eze, and I had heating problems too.
One of the many reasons I sold it.

Hey John,

Did you miss my last post in this thread about your R2800??? I'm curious as to what that's about...