How about some input on engine choice

[JohnR]

I've been trying to decide what engine to use. All along I have thought I would use an IO-360 but wasn't sure which one. I spoke with BPE at Osh and was really impressed with what they offer. Today I spoke with Allen Barrett again and got a quote for an IO-360 M1B. Nice engine and good power while being fairly light at 275 pounds.

The problem is we then talked about the I0-390. It puts out about 30 HP more and is only another $3,000. Yeah, I know it is a fair amount but in the overall picture not that much. The problem is another 33 pounds and on the nose at that. I plan on using a James cowl and will have the prop sticking out there a little farther than the standard Van's cowl already. I'm a little worried about the extra weight if I were to go that way.

Then my thought was that I could just use a Whirlwind 151 3 blade which only weighs 28 pounds. After all it is only another $1,500 over the Hartzell from Van's.

Someone quick hit me over the head and bring me back to my senses. I kind of feel like a snowball that is headed downhill on this. Most of the RV's I've flown in are running the O-360 I believe and they all perform excellent. Does a person really need more than the 180 HP? Absolutely not. But this is one are I have always had a problem with. I like the power. I just don't want to lose the RV handling that I have seen and felt in the RV's I've been in.

Can you offer any suggestions or advice that will help me settle this? (I'm pretty sure CJ won't be much help in bringing me back to reality as he has the same problem I have. I've read his comments on the 390 already.)

Sorry to be so long on this but it is driving me nuts.

I am building with my main mission being cross country travel at this point.

Also, what engine vendors are all of you planning on using?

[svanarts]

I'm planning on the Superior XP-360 with a Hartzell Blended Airfoil prop.

Can't give you much direction on engine choice because I'm fairly clueless when it comes to power plants. You put in oil, you put in gas, it goes. That's my knowledge on engines.

[Spike]

Superior O-320 with 151 prop for me, well, hopefully anyway. Keep the power in perspective I would say. I have a good friend that is flying an 8A on 160HP and he gets great numbers. He's doing close to 150kts on 6.5GPH .

Power to need ration is always relative!

[N200PF]

Hey John what is Allen telling you you'll see in terms performance difference for that 33 lbs and the $3k? He should have a general idea of what 215 hp will do over 180 hp with the additional weight.

Also, did you look at the Hartzell ASC II prop? I havn't seen a price on it yet but they're saying it should come in significantly less than the other composite props out there today based on some new manufacturing technology. (If anyone could afford to invest in that part of the process it's Hartzell) They also claim a 30% lower weight than metal blades with all the performance of the blended foil props they produce today.

My plan is to put the biggest engine I can under the Sam James cowl with a light weight prop. I can make up that 33 lbs in other ways even though it sits out front. There are lots of ways to keep a plane light! (...guess I'll dump the in-flight DirecTV system!)

- Peter

[cjensen]

I thought about jumping on the big displacement wagon when they came out. What keeps bringing me back, is the fact that I've flown a bunch of times now in a ~185hp -7, and the performance is simply amazing! I'm not sure what the BIG advantange is truly going to be with the -390 and -400 engines. CJ, pipe in here anytime...

They are heavier. If you want to build light, build with a lighter engine. Light RV's perform and handle WAY better than heavy ones...I don't have personal experience to back that up, just what I've heard and read.

I'm planning an O-360 (that I may build up myself, well, with the help of our shop) with a three blade Catto. I'm looking for a good 360 core to put new ECi or Superior cylinders on it. I'll send the cylinders out to Lycon to have them ported and polished, and that should yield me a 7 to 10hp gain while still running standard 8.5:1 pistons.

I just about ordered a Catto prop yesterday, but decided to wait until after I get started on the fuselage...that'll give me time to WV about it for a couple of months... Brit is on board for the Catto purchase!

[RV7Factory]

John,

I am right there with you, thosa are the same issues I am looking at. Remember, along with you and Chad, we are the three-stooges.

I am not quick to jump on the displacement bandwagon. Sure the 390 is a nice engine, and I am considering it, but as you pointed out it does come with a weight penalty.

I too talked with Allen and Rhonda, also Sue at Aerosport and Mahlon with Mattituck, and all of them came up with what I think is a good alternative. An IO-360 (parrallel valve) with Fuel Injection, Electronic Ignition, Ported & Flowed, Lightweight Sump, with a 4-into-1 exhaust and maybe 9:1 compression. All agreed that this would be a very nice engine and produce around 195HP, possibly more. Of course you could do all this to the 390 and get 225HP.

Now mate that engine with a lightweight prop, and how many pounds are you saving over the 390 with the hartzell?

Honestly, I don't know which direction I will take, but the more this topic comes up at the EAA Saturday breakfasts, the more I get talked into buying/building a lightweight but well built/tuned engine.

I think we builders tend to jump on the bigger is better bandwagon (myself included), but I am skeptical. I am not yet convinced that a big (displacement) engine is the way to go (see Chad's comments).

[RV7Factory]

John,

One more data point...

I talked to a builder at OSH who is running the angle valve 360 (roughly the same weight as the 390). He said he likes it, but in certain weight/flight configurations he occasionally runs out of trim.

Now, I have no knowledge of how his plane is set-up, but I do know he was not using the SJ cowl, which, as you pointed out, would obviously have additional effects on CG.

He gave me his name and number and told me to call him at any time if I had questions. If you want more info, I would be glad to pass his info onto you.

[captain_john]

The flame that burns twice as bright only burns half as long.

There are several reasons why I am considering (yes, I do have a plan B!) the 390.

One, I have always been power hungry. The hot 360 could be cantankerous and tempermental. It COULD be prone to pre-ignition, high temps, low TBO's and tough to start when hot. I say COULD because these are all relative and if addressed properly, possibly non issues. I just think that the 390 would mitigate most of these items.

Two, The -7 likes a heavy engine. Take a look at Dan's W&B section. The heavy engines do not go out of CG and are actually better suited for carrying stuff in the baggage area! Without baggage, you are even farther forward! Brad, I wonder if that guy who runs out of trim is either rigged wrong or carrying too much stuff?

Three, With GOBS of power, throttling back to a nice low cruise RPM and a lower MP could produce good cruise speeds with good economy! I understand that the standard 390 is supposed to use 11 plus GPH, but at reduced MP's and RPM's with a CS prop (like there is any other way with a 390!) the potential for economy and speed exists. Of course, this is all hypothetical and thi is why we do experiments with airplanes!

My $0.02...

CJ

[cjensen]

I could possibly agree with one and for sure two...however, three hangs me up. They do have more power. But GOBS more??? If by GOBS, you mean 10 more, ok. But there's only 7mph difference in cruise at 75% between the 180 and 200 horse engines (same airframes). If we extrapolate the numbers to compare 200 to 210, you're only going to be 3, maybe 4 mph faster...that's an EXPENSIVE 3 or 4 mph, and burn more gas.

I'd be willing to bet a good balanced, ported, and polished carb'd 360 with a max cruise pitched Catto would be as fast with SLIGHTLY less fuel burned...

[RV7Factory]

The hot 360 could be cantankerous and tempermental. It COULD be prone to pre-ignition, high temps, low TBO's and tough to start when hot. I say COULD because these are all relative and if addressed properly, possibly non issues. I just think that the 390 would mitigate most of these items.

The 390 is stock with FI, so it COULD also be hit with hot start issues, which as you point out are easy enough to deal with today. On the other issues, I suppose it could be prone to them, but if built right (a well tuned engine not pumped up) the chances should be relatively small (as you said). Of course, I could regret saying that.

You want to talk about HOT / Pumped-up engines... I saw a sale flyer at the airport the other day for a 260HP RV-8. At first I though it must have a stock 540 in it, but no, he had a Lycon IO-360 in it. IIRC, 11:1 and all the goodies. Lycon just being Lycon.

[captain_john]

I could possibly agree with one and for sure two...however, three hangs me up. They do have more power. But GOBS more??? If by GOBS, you mean 10 more, ok. But there's only 7mph difference in cruise at 75% between the 180 and 200 horse engines (same airframes). If we extrapolate the numbers to compare 200 to 210, you're only going to be 3, maybe 4 mph faster...that's an EXPENSIVE 3 or 4 mph, and burn more gas.

I'd be willing to bet a good balanced, ported, and polished carb'd 360 with a max cruise pitched Catto would be as fast with SLIGHTLY less fuel burned...

Never ONCE did I cite speed.

I am talking torque here. Bringing the RPM's down and operating the airplane within the speed envelope of an engine with less power SHOULD yield the same results.

No doubt, it does cost more money.

I am not building an airplane to save money.

CJ

[captain_john]

The hot 360 could be cantankerous and tempermental. It COULD be prone to pre-ignition, high temps, low TBO's and tough to start when hot. I say COULD because these are all relative and if addressed properly, possibly non issues. I just think that the 390 would mitigate most of these items.

The 390 is stock with FI, so it COULD also be hit with hot start issues, which as you point out are easy enough to deal with today. On the other issues, I suppose it could be prone to them, but if built right (a well tuned engine not pumped up) the chances should be relatively small (as you said). Of course, I could regret saying that.

You want to talk about HOT / Pumped-up engines... I saw a sale flyer at the airport the other day for a 260HP RV-8. At first I though it must have a stock 540 in it, but no, he had a Lycon IO-360 in it. IIRC, 11:1 and all the goodies. Lycon just being Lycon.

...and this was the reason Dick Martin went with the IO-390. He was eating up 360's and making too much metal, too often.

Now, I am willing to bet that he has heated up the 390 a good amount too!

I am saying this because that -8 just MOVES, pure and simple!

CJ

[cjensen]

I am talking torque here. Bringing the RPM's down and operating the airplane within the speed envelope of an engine with less power SHOULD yield the same results.

Ohhhh...torque. Missed that part earlier I guess...What kind of torque values are there between the 360 and 390?

Why spend the money to achieve the same results?

I hope I'm not pissin' you off CJ...I'm just as curious as everyone as to why the money spent is worth it. I guess the cheap SOB in me is coming out here.

No doubt, it does cost more money.

I am not building an airplane to save money.

CJ

I am...

[RV7Factory]

...and this was the reason Dick Martin went with the IO-390. He was eating up 360's and making too much metal, too often.

Now, I am willing to bet that he has heated up the 390 a good amount too!

I am saying this because that -8 just MOVES, pure and simple!

Yea, but what did he do to the 360? Meaning what enhancements/goodies did he bolt on that caused it to wear? How was he running it? How much power was it putting out? I ask because I am curious.

His -8 certainly does move, but it has no paint, very minimal equipment, SJ cowl and plenum. It is ALL built for speed... it's not just the engine.

[captain_john]

..and yet a THIRD POST!!!

I just got off the horn with Tom Green at Van's. He told me that Lycosaurus wanted to make him a dealer for the 390. He said no thanks.

The reason was that the planes were not "designed" for more than 200 horses. I said, okay then... if we govern them down to 200 HP what is the sticking point then?

He mentioned the fact that at altitude it could still make more power than a 360. Then the pilot would be potentially overpowering the plane AGAIN! I asked if it could then lead to flutter and he did a moonwalk around that one.

I then mentioned the empirical data of some really hot 360's which are equal in HP and performance. He said that Van doesn't agree with that either. Bottom line again was the airframe was designed for 200 HP.

Sooooo, then I asked if this decision was based on a best guess (and who better than Van to do the guessing) or actual, HARD DATA ANALYSIS.

I got a CORPORATE moonwalk! This one was really fancy and included the fact that of I lived in Canada I couldn't do it and so forth and so on.

All said and done, he suggested a prop for the 390 with the SJ cowl and said that they could provide it if I wanted it!

Bottom line, 201 is too much according to Van. It is probably his conservative nature, but so am I! Maybe a good running 360 with a polished spinner would work really well?

I dunno... A trip to Mattituck on the 9th might either clear up or cloud this issue up alltogether!

Now, wouldn't it make a suitable engine for the -10? I forgot to ask him that!

BTW, I know that this WILL NOT make the plane much faster! That ISN't Why I am doing it. I am doing it for climb performance! I get a kick out of takeoff power and climb performance!

CJ

[RV7Factory]

Interesting, very interesting.

[cjensen]

Well, now that is a great reason! Climb!

Interesting conversation with Tom...thanks for posting that.

I am really looking forward to your 390 install CJ, so I hope you do it!

[captain_john]

I will keep you guys posted.

Chad, nawwwww... I like talking about this stuff. Otherwise, I wouldn't be so verbal!

I really LIKE the 390 and what it has to offer. I want/need to/should/WILL give this whole thing due diligence! This is all PAR for the COURSE!

I just don't want to stew in the nether regions of indecision!



At this stage of the game, I am poised to go left or right... 390 OR 360. I just like the idea of the 390. If I do go 360, it'll be HOT!!!

Which brings me to Dick's old engine that was making metal. We have an Express Cruiser here at KPYM that has an IO-360-AIB6 kinda engine. The guy who owns it CLAIMS 250+ horsepower!

Now in order to get that kind of power, you make ALOT of comprimises. Mostly trading off good manners (run quality, temperatures, TBO, start ease and general cantankerousness) with an increase in power.

You DON'T get BOTH sides of the coin!

That is why I want an engine that just simply moves more air, not moves air in a more complicated manner!

CJ

[JohnR]

Wow! This is all good stuff!

Peter, I did not ask specifically about the speed difference. I probably should have but I had already determined it might make 7-8 mph based on what I had read and Van's charts on the website. I'm pretty sure more than 5 and less than ten. 30 HP is a lot but it is hard to increase speed with HP once you get into the 200 mph range according to all I can find. That is why I plan on the SJ cowl, free speed in my mind. We'll see.

I don't think the weight will have any effect on speed. 400 pounds only makes 1 mph difference according to Van's chart.

Brad, maybe we fit that three stoogies category pretty well. I am thinking that the engine I will probably end up with is the IO-360-M1B (parrallel valve horizontal induction) with 9:1 compression, EMag/PMag and Vetterman exhaust. I really want to get my engine from Barrett, their stuff is like artwork to me. It does come at a premium but I believe in the long run it may very well be worth it. I have never kicked myself for buying the best but have often wished I had bought something better when I compromised on a purchase.

By going to the 9:1 compression it gets you into the 185-188 HP range which would be a good place to be and also the higher compression is a little more effecient. Flowing the heads might be a good idea also.

Like CJ I have always been big on HP but in this case I do not want to get greedy.

As far as Dick Martin's 8 goes Luke summed it up pretty well last summer. We were at the RV flyin at Boone, IA and Dick made a low high speed pass down the runway with a pull up to a vertical break at the end taking him back to downwind. As he approached I poked Luke and pointed at the 8 coming toward us. We both stood and watched as he went by. As he entered the downwind all Luke said was "Cool." Not much more to add. There is no doubt taht Dick sqeezes all he can out of the 390. Allen told me that there was nothing on Dick's plane that didn't make it go faster.

By the way Allen is building an RV7. It will have an IO-390 on it. What else?

[JohnR]

What is the consensus on the prop if using a SJ cowl? It will be sticking out there a little farther, 2 1/4 - 2 3/4 inches, so would a person be ahead to go composite or do you think the weight of the Hartzell would still be beneficial?

I don't plan on any heavy areobatic type stuff so am not worried about the extension. However the lighter weight would be nice for helping with useful load as long as I can stay within CG limits. Comments? Thoughts?