Engine choices revisited

Sorry guys/gals,
But I would like to discuss RV-10 engine options. I've read all the old posts, but as a newbie I would like to get a better handle on the issues. I'll list the issues that interest me and hope somebody will comment on any or all.

? The Van's folks worked out that the machine needs 210 to 260HP. One plane has the Lyc. IO540-D4A5 for 260HP and the other has the Cont. IO360-ES for 210 HP. From what I can glean out of the old posts, the Continental engine is 100 pounds lighter but costs virtually the same. From what I've read the Continental gives similar performance numbers as the Lyc. The Lycoming seems to have a great reputation, and the "ES" Continental seems to have overcome a bad reputation. Vans now says that they will not support a firewall fwd option for the Continental because of a lack of buyers.

? I know about the Mattituck clones, etc., but all that talk is about mods of the same engine. We really have only one engine choice that fits the Vans mounts, right?

? I'm not looking for that last 5 knots, I want to save 100 pounds.

? Are the Lyc four-bangers even an option?

I've got a thick skin and newbies are always allowed stupid questions, right? Fire away.

John Goodman

Not stupid........

Mornin' John,
It's not a stupid question, rather one that makes me ask, "Why?" Van has what must be the very best value or "Bang-for-the-buck" and already someone wants to re-engineer the motor mounts for a four-banger! Build a 7 or an 8 if you want to do a 4-banger.

In our case, we wanted to fly more than build, plus we figured that Van's engineers/marketing folks know a lot more than we do and that it would be wise to listen to them. So we built a QB 6A with a 180 Lyc and were flying with no problems 22 months later (Nov 2006) and already have 98 Hrs on it. Then again, if you want to join the Eggenfellner/Rotary/V-8 Corvette/V-6/ Turbine engineering guys, that's what EAA is all about.

Your desire for a four-banger or Conti just to save a 100 pounds is gonna cost you a lot in terms of rearranging the CG, fabrication and a host of other unforeseen problems. If that's what floats your boat, go for it. Let us know how it goes,
Sincerely,

Well,

I really was surprised that Van did not go with at least an enginbe mount for the continental, seems more in line with his build philosophy than exclusively having the big Lyc.

I also wonder about the IO-390...lighter still, and a good value on the engine market. Perhaps an engine mount will be available for that, there are alot of four seaters out there which fly just fine on 4 cylinders.

Go with the flow

The wisdom I might impart and bottom line is, the path of least resistance is a Lycoming O540. As far as I know that is the only engine supported by Van's aircraft, engine mount wise. You don't have to push the throttle wide open.

As far as the Continental I have a good amount of time flying them in Mooney's and Seneca II's. I was not a owner and flew them as CFII and Freight Pilot. I never had a big problem but than again I was not paying the maintenance bill. In general they do have a bit of a reputation for turbo issues. There have been improvements in the design and systems (turbo) in later versions and thru aftermarket STC's. Look ANY turbo plane is going to be more expensive. Also to take advantage of the turbo you might need to fly in the low teens, which necessitates the use of O2, another hassle and expense.

As far as power, you are flying a 4 place plane. There may be a day when you need it. High, Hot and heavy. It's easier to make HP with 540 cubic inches than 360 cubic inches. When solo you can dial the RPM back to 2500 rpm for take-off if you want, call it de-rating the take off. This is what all the big jets do. They are rated for gross weight high altitude takeoffs and the ability to take-off single engine and climb, so they are over powered in general with both engines working. With less than gross Wt., cooler temps, long runways and no climb obstacle, the jet engine thrust can be lowered safely for takeoff saving gas and wear on the engine.

I would not look at it from a top speed standpoint.

Weight is important, but W&B is critical. The IO-390 can make 210 HP or more, but you are looking at a new engine mount. Why do that? You can get a O540 for the same price or less. Besides the W&B of the plane is designed for the 540. I have not crunched the numbers but you may end up tail heavy with a light engine. I can give you a RV-7 example. With a 320/wood prop the dash 7 is very restricted due to aft CG issue, since it was designed for a IO360 angle valve (200HP) and Hartzell C/S prop, about as heavy a combo as you can get. I am all for light but light in the wrong spot can cause some W&B issues.

George,

What do you think of the normally aspirated continental? I understand that the one Van's uses is normally aspirated, similar to the Cirus SR-20.

I suppose it is typical, but as my 7 is coming to a close, I am thinking of another build...well, fantasizing really, and I just wonder about a lighter 10.

Oh, and as to W&B, I got the impression from Vans that with lightweight 540, the 10 is at the foreward limit, even with a rear battery, just a thought.

Conformist

Jconard said:

George, What do you think of the normally aspirated continental?

Click to expand...

Well I think TCM's are fine, but have to admit I am a bit of a Lycoming man. It's being a Chevy or Ford man or gal. However in my old age I'm becoming a bit of a conformist. Atmo or Turbo engine, the same applies, it doesn't fit (as easy) as the 540 Lyc. The Lyc 540 is just a 360 with two more Jugs. We know that you can get cheap parts (relative term I know) from Lyc, ECI and Superior. So I said forget the Continental (as smooth and pretty of an engine they might be) for the Lyc.

I don't know TCM's as well as Textron. I do know when I flew between the C-182 (large TCM) and the C-182RG (Lyc) the TCM was smoother. As far as maintenance, I don't know. Again I was not paying to fly them or maintain them. I guess market and volume play a part in maintenance. I'm going to guess the Lycoming would be cheaper to maintain since parts are cheaper?

If YOU MUST have the Continental you can do it, but than again why? You are giving up about 40 HP, not cheaper to buy and install and longer build time is likely. It gets down to opinion and prefrence. I guess the BIG Continental does not fit in the RV-10? Too Bad, but therefore by default, the Lyc 540 is what I would use.

As far as W&B, nose heavy is a little better situation in a plane with aft passengers and baggage. The Seneca II was the same. A case or two of oil in the trunk made it fly better. Call it "flexibility". Aft CG is not great, since more cargo makes it get worse. My RV-4 with a constant speed prop was the same. Solo it was a little nose heavy, mostly noticed on approach, requiring full nose up trim, but with passenger and all the bags I could stuff in the trunk I was fine.

A Few Comments on the TCM IO-360

The TCM IO-360 was originally developed for use in the Cessna Skymaster. TCM later modified the engine for use in several models of the Seneca. The engine runs smooth, but it tends to be a high maintenance engine. Cores are not readily available for o'h due to its limited use in the certified market, and it has lots and lots of parts so it's expensive to o'h (much less buy one new.) It is a bed mount (which most TCM engines are except for the 520/550 C models.) The engine has a tendency to run hot, which can be dealt with for an experimental, but we feel the TCM 360 isn't a very good option. We have recently quoted an IO-390 for a -10, so others are thinking about it as an option. Not sure how he plans on handling the mount issue.

Rhonda Barrett-Bewley
Barrett Precision Engines, Inc.
Tulsa, OK