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iowaflyer

Active Member
First time poster here--so please be gentle. BTW, I have checked the archives but wanted to get some new opinions.

I've just ordered the empennage kit for an RV-7. I'm trying to finalize my choices with regards to prop and engine. I know I want a non-certified FI IO-360 (IO-360-M1B) and I THINK that I want the horizontal induction with the forward facing induction (cold air). For simplicity, I'm going to stick with good old mags.

My questions:

Who should I get the engine from? I've priced out Mattituck and Aerosport power for a new engine. They both tell me that only new engines are available; overhauled are very hard to find and the price difference isn't that great anyway. Anybody else to consider? Is there anyone that can provide an OH'd engine?

Is the cold-air induction worth it?

I'm a first time builder and want to keep things relatively simple. Is the above setup with a Hartzell blended airfoil CS prop going to generally work OK with the Van's-supplied cowl/mount/firewall forward kit without much modification?

Any other suggestions/modifications to my engine choice?

74" or 72" prop?

Thanks in advance--I appreciate the great advice that the forums provide and I'm sure I'll have plenty of questions later on.
 
If you go with horizontal induction, make sure to check with Vans on what, if any, fabrication is necessary to route your intake air from the filtered air box, which is typically placed just inside the cowling air inlet on the left side. This may add a complication that you wouldnt have to deal with using vertical induction. It will defintiely save time to use an engine that Vans has a standard kit setup for.

Are you sure you dont want to consider electronic ignition, at least on one side? There's really nothing complex about it, and it has definite advantages.

erich
 
I've been told that use of autogas may not be possible with electronic ignitions--something about advancing the timing/higher peak pressure/risk of detonation. Any truth to this?
 
iowaflyer said:
I've been told that use of autogas may not be possible with electronic ignitions--something about advancing the timing/higher peak pressure/risk of detonation. Any truth to this?
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Compression ratio, octane rating of the mogas, and possible ethanol content have more effect than EI. Not saying EI doesn't change the game - but it's not the major player.
 
You can't go wrong with Van's recommendation: fixed pich and carburated. I installed two TMX O360 engines and am favorably impress with how smooth they run. Put Van's Sensenich props on. Haven't had to have a prop balance done on either. Help and service from Mattituck was excellent. Use the money you save on something else.
Al
 
iowaflyer said:
First time poster here--so please be gentle. BTW, I have checked the archives but wanted to get some new opinions.

I've just ordered the empennage kit for an RV-7. I'm trying to finalize my choices with regards to prop and engine. I know I want a non-certified FI IO-360 (IO-360-M1B) and I THINK that I want the horizontal induction with the forward facing induction (cold air). For simplicity, I'm going to stick with good old mags.

Great choice on the airplane! I don't fault the mags choice, either.

My questions:

Who should I get the engine from? I've priced out Mattituck and Aerosport power for a new engine. They both tell me that only new engines are available; overhauled are very hard to find and the price difference isn't that great anyway. Anybody else to consider? Is there anyone that can provide an OH'd engine?

Don't overlook Barrett, (BPE), they have an ad just to the left on this page.

Is the cold-air induction worth it?

I can't say, but I like the cowl shape and my engine puts out about 195 hp. (I have 9:1 pistons).

I'm a first time builder and want to keep things relatively simple. Is the above setup with a Hartzell blended airfoil CS prop going to generally work OK with the Van's-supplied cowl/mount/firewall forward kit without much modification?

Short answer is yes. I have this set up with the Teledyne Mattituck IO-360 M1B, (horizontal sump) Hartzell BA, but with one Lightspeed ignition. One caveat... I chose the SilverHawk fuel injection to avoid any cowling issues. It worked nicely.

Any other suggestions/modifications to my engine choice?

I'm very happy with my TM engine. It is smooooth. Barrett, TM, and Aerosport all have excellent reputations and support. For me, it came down to a bit less money when I started piling on the options. Prices have probably changed.

74" or 72" prop?

I went with the 72" but you can argue either way. Some say that the 74" gives you two inches to work with if you ding a tip. My thought was that if you didn't have that extra 2" on a taildragger it may keep you from dinging a tip in the first place. The prop performance should be about the same either way.

Thanks in advance--I appreciate the great advice that the forums provide and I'm sure I'll have plenty of questions later on.
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Sounds to me like you've done some good research.
 
Lots of choices

You've got ECI and Barrett Precision close by. Either would be great. I have an ECI built by Robbie Attaway (mentioned earlier). My next engine will be an IO390 by Barrett Precision.

Props-I highly recommend the Whirlwind 200RV prop. It was designed for the RV airframe. The 200 is extremely smooth and efficient.

You've got lots of time before you need the engine. Things will likely change with improvements and modifications over time. Who knows, the prices might come down, yeah right!!!
 
In regards to "fixed pitch"; there are a lot of us RV'ers that fly a 150 miles to brunch on Sundays.
Now we do operate out of higher altitude airports and have mountains to deal with. The fixed pitch versus constant speed, often comes up at the table discussion...........because I bring it up! :D

And the consensus is.................not one RV owner with a C/S would prefer to go back to a fixed. And most fixed owners, would prefer a C/S after seeing how well ours do! :)

So take this for what it's worth.... ;)

L.Adamson --- RV6A
 
iowaflyer said:
I've been told that use of autogas may not be possible with electronic ignitions--something about advancing the timing/higher peak pressure/risk of detonation. Any truth to this?
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Funny, I wonder how my car operates on autogass and EI?

Seriously, they work just fine and many of the EI systems will alow you to tune them for 100LL, auto fuel, etc., if you want. That is not required to run auto fuels, so don't let that scare you off.

The two big EI vendors out there right now are E-mag and LightSpeed. Research both as they each have their good points.
 
None whatsoever

iowaflyer said:
I've been told that use of autogas may not be possible with electronic ignitions--something about advancing the timing/higher peak pressure/risk of detonation. Any truth to this?
Click to expand...

I run my IO360 (a Mattituck) on autogas with or without ethanol on an E/Pmag combo....Both ROP and LOP

Can't remember the max advance (its adjustable) but Inever altered it from what it came with..I want to say 38 degrees of total adnavce but I don't know for sure.

Do not increase the compression ratio beyond 8.5:1 and run it on premium.

Frank
 
Today I bought an ECI engine and prop governer with Horz. induction.

I could no longer wait for the american economy to recover, so the american economy will have to catch up to me.

Merry Christmas America :D
 
I am sure I will lose sleep over this one as well...

I will be starting my build next month after my SportAir class, but have been thinking about this for a year now. I know Ken at Van's, in a conversation at Oshkosh told me "keep it simple, keep it light".

I will most likely (subject to change at least 20 times between now and FWF) go FP Prop with a 180 hp rebuilt engine on a -7A. Yes, I could spend more going with a constant speed prop, higher hp engine and squeeze every knot out of the plane, but for me it's also a matter of perspective.

I used to own a Mooney 201 with a CS prop and a 200 hp engine. My annual inspections were $4k+. With an RV, I can get BETTER performance with a cheaper FP prop, smaller engine and fixed landing gear. Granted, I will be two seats instead of four, but the payload is almost the same :) I fly out of a 4577' paved sea level runway and with my -7, I will leap into the air under 600'. It works for me.

Of course, I will (over the next three building years) read countless threads over this issue, and will crunch the numbers at least a dozen times, but for now this makes sense. I want to build a simple, efficient fun airplane - the fact that I can do it and get better performance than my previous Mooney is just a wonderful plus. I will keep it simple and light :)

On the engine, my plan is to rebuild one myself (subbing out the cylinders, etc). I will do it hand-in-hand with the A&P who maintained my Mooney - as we have become friends. This way I will learn the engine side of the build, do it per Lycoming specs, and be more comfortable with engine repairs / issues in the future.

my 2c
 
Fixed pitch vs C/S

L.Adamson said:
In regards to "fixed pitch"; there are a lot of us RV'ers that fly a 150 miles to brunch on Sundays.
Now we do operate out of higher altitude airports and have mountains to deal with. The fixed pitch versus constant speed, often comes up at the table discussion...........because I bring it up! :D

And the consensus is.................not one RV owner with a C/S would prefer to go back to a fixed. And most fixed owners, would prefer a C/S after seeing how well ours do! :)

So take this for what it's worth.... ;)

L.Adamson --- RV6A
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Interesting statement:

I have a RV7 with IO-360 and Hartzell prop. If I didn't operate off a short grass strip I would consider the Fixed pitch. Less cost to buy and maintain and the preformance difference above 90 knots isn't that great. T/O and landing yes. but climb and cruise?

Peter
 
kiwipete said:
Interesting statement:

I have a RV7 with IO-360 and Hartzell prop. If I didn't operate off a short grass strip I would consider the Fixed pitch. Less cost to buy and maintain and the preformance difference above 90 knots isn't that great. T/O and landing yes. but climb and cruise?
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As I said, FWIW...:)

We live and fly in the Mountain West of the USA. Typical airport altitudes are in the 4000 - 7000' msl range, let alone density altitude. Climb & cruise? You bet! :D

I wouldn't take a F/P if it was given to me... ;)

L.Adamson --- RV6A
 
FP vs CS prop battle

I have a Catto three blade on an O-360 in my -6A. Ideal would be constant speed for better climb performance and the ability to drop the RPM during cruise with those benefits.

I just can't justify $10 K USD to make that change. Starting a project it would be BIG engine and CS prop. Personally I doubt that many people will not buy a plane because it has a CS prop. I suspect that many will avoid a plane with fixed pitch because they want the advantages of a CS prop. Just my opinion with no data to back it up. I bought mine and the prop type was negotiable. Engine size was not!
 
It's only money. I ended up with the superior XP360 and put the blended CS 72" to me smaller makes sense, ground clearance and weight. I was set on two mags, but all the sudden I find myself with a plasma III on top. I went vertical because I wanted mufflers, you can only do mufflers with a vertical setup. Quiet is good. When you like performance, quiet is good. Don't ask.

You need to make up your mind what you want in an aircraft. If it's to show off(looks, and that includes the panel), than build with a smaller engine, if it's to perform, than put in the engine and prop and skimp on the rest.
 
Ron Lee said:
I... Personally I doubt that many people will not buy a plane because it has a CS prop. I suspect that many will avoid a plane with fixed pitch because they want the advantages of a CS prop. Just my opinion with no data to back it up. I bought mine and the prop type was negotiable. Engine size was not!
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Some might avoid the CS prop because of the weight penalty. There are some people out there who will not fly their RV over the Van's recommended GW and others who will. (Apparently a lot who will.)

Performance has many parameters and high useful load is one of them. My two blade Catto prop is 9 lbs, which helps give me a 760 pound useful load with the RV-9 recommended GW of 1750.

Remember, people have flown C-172's out west in and out of those high elevation airports L.A. keeps talking about for years. A FP RV of any color/engine/etc. will outperform those factory birds hands down. (Granted, a CS RV will outperform a FP RV but at what cost?)
 
N941WR said:
Some might avoid the CS prop because of the weight penalty. There are some people out there who will not fly their RV over the Van's recommended GW and others who will. (Apparently a lot who will.)
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And why not....

Van's weight numbers have always been on the conservative side. Thousands of flying airplanes have proven what the airframe can actually take.
We set our "legal" gross weights, and I have no problem with the 1850 lbs. I stamped on my my 6A. Either does the airplane.

And BTW, I'm still getting a few "this fly's like a rocket" comments from a few other RV owners. I know a "Harmon Rocket/F1" pilot won't be saying that anytime soon................but I don't mind it from the other guys.. :D

L.Adamson ---- RV6A/ 0360/ Hartzell CS
 
L.Adamson said:
And why not....

Van's weight numbers have always been on the conservative side. Thousands of flying airplanes have proven what the airframe can actually take....
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LA, I'm saying there are some people who believe the engineers and fly within their recommendations. I didn't say it was good or bad, just that some people follow the designers.

As for "thousands of flying airplanes...", if your friends jumped of a cliff, would you? ;)
 
N941WR said:
As for "thousands of flying airplanes...", if your friends jumped of a cliff, would you? ;)
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If I'm seeing the thousands of airplanes surviving, and the friends jumping off cliffs......not....

then no...

L.Adamson --- RV6A -- "classic tail"
 
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