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LIO-360 on RV-4

1

1flyingyogi

Well Known Member
Hi guys. I'm looking at an RV-4 that has the LIO-360 (reverse rotating), 200hp engine to buy. I've read mixed opinions about this engine for the -4. Some say the 200hp is not worth it for the added weight (about 40lbs?) compared to the parallel valve O-360. Others seem to be very happy with their 200hp angle valve engines in their -4's.

Anyone care to comment based on experience with either (or both) the 180 and 200hp engines? Besides the added weight, any other disadvantages of the IO-360 angle valve? What about fuel burn? Anything I should look out for in particular when deciding on my purchase?

Thanks!

Brian
 
I have 200 HP parallel valve IO-360 and love the added vertical performance. 100 kts on take off produces 3,700 fpm solo, 80 kts buries the VSI at 4,000+. 25 squared gives me 192 kts at 3,500.
There is no substitute for horsepower.
 
Horsepower = fuel burn rate

1flyingyogi said:
What about fuel burn?
Click to expand...

Fuel burn rate is basically equivalent to horse power produced. A 200 HP engine running at 90% would get basically the same fuel economy as 180 HP engine at full power. The only difference is minor fuel efficiency differences between the two engines.

So the question is: are you going to keep the engine throttled down to have the same burn rate as the smaller engine? :D Not me.
 
The big question is the direction of rotation, especially if going constant speed, it seems the availability of props gets reduced. Also, if you are doing a hammerhead, it will be right rudder instead of left rudder just like the Sukhois.
Fuel burn is easily adjusted downward in cruise settings. At 9,500 ft I am burning 8 gallons an hour getting about 170 kts. (Appx. I don't remember the exact settings).
I'm still smiling from my last takeoff though.
 
Mike,
Just want to compare some numbers with you. I have 180 hp in mine. what are the units on the numbers below? Is the altitude in ft MSL, AGL, is that ft density altitude or pressure altitude? are the kts IAS or TAS? Thank you.

- 25 squared gives me 192 kts at 3,500

- At 9,500 ft I am burning 8 gallons an hour getting about 170 kts.
 
Just as a basis for comparison, at 9,500 MSL I can generally do 170KTAS at 8.5GPH in the Rocket.

The overall airframe drag is what dictates HP/fuel burn at speed.
 
Left hook...

1flyingyogi said:
Hi guys. I'm looking at an RV-4 that has the LIO-360 (reverse rotating), 200hp engine to buy. I've read mixed opinions about this engine for the -4. Some say the 200hp is not worth it for the added weight (about 40lbs?) compared to the parallel valve O-360. Others seem to be very happy with their 200hp angle valve engines in their -4's.

Anyone care to comment based on experience with either (or both) the 180 and 200hp engines? Besides the added weight, any other disadvantages of the IO-360 angle valve? What about fuel burn? Anything I should look out for in particular when deciding on my purchase?

Thanks!

Brian
Click to expand...

Brian,
The LIO-360 in the Spitfire RV4 is a unique engine originally installed in twins to reduce P factor. There were several AD"s as I recall, all accessible on line. Make sure the crank AD has been complied with or its unaffected by serial number. As far as it being odd, I have quite a bit of M-14P (Sukhoi, Yak) time which spins "Left" as well. It only took one flight doing acro to get used to it. It should provide 170KTAS under 10GPH with the right prop and LOP.

My thought is if it's working and flying well, don't spend extra bucks for little gain. Counter-weighted crank IO-360's run smooth but are heavy. Bargaining chips for sure...

It could be a great airplane if the price is right. :)
V/R
Smokey


PS: In 2000 I converted a 0-320/wood prop powered RV4 to an angle valve IO-360/Hartzell. Added 92lbs to the EW, doubled rate of climb and takeoff fuel burn but also gained 12knots in cruise and equaled the old fuel burn at lower speeds. Still had a noticeably heavier nose (not as much as my HR2 solo!) and feel even with the battery in the baggage compartment. The lighter they are, the better they fly....
 
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Michael Henning said:
Axel,
Altitude is msl, speed is true.
Click to expand...

Thanks Mike.

Brian,
a few comparison numbers for you since you asked about 180 vs 200 hp.

My plane:
-RV-4 air frame with fastback and rocket canopy
-sam james cowl and wheel pants
-engine plenum
-IOX-340 with electronic ignitions

-Full open throttle, leaned out rich of peak, 8500 ft msl gets me 189kts true (corrected/verified) burning about 9.5-9.6 gal/hr. I don't have all my fairings on yet and my horizontal stab angle of incidence is not where I want it yet. So I am hoping I can get to 190 KTAS after the changes.

-At my normal cruise (2650 rpm, fix pitch, cant remember MP), lean of peak, 8500 ft msl gets me 174kts true burning about 7.4-7.6 gal/hr.

That being said, all our air planes can't really be compared apples to apples. Some have electronic ignitions, some take painful approaches to reducing drag and drag cooling and some just build to plans.

Like Smokey said. If the motor is a good price, who cares. The only opinion that matters is yours. You can reduce some of the empty weight if you go to a fix pitch prop. If you go that route, pick a company that has experience making props for the pusher communities (i.e. Catto, etc).

Good luck.
 
You might check with the RV 4 plans. Normally either the motor mount or Vertical stab is angled a few degrees to compensate for the prop rotation / p factor. If it is only the V stab alignment, that is easy to do. The motor mount, not so easy.
 
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Thanks for all the replies. Great info. That deal is a no-go, though. It's got a history of engine issues and compressions currently are 70, 65,66, 71. And although the paint looks great, I'm not crazy about the scheme.

But I ended making a deal for another -4 nearby. It's close to new, with 270hrs E/ AF, great condition. The only thing is it's got the O-320, instead of the O-360, which I really wanted. But for the price and with everything considered, I think I can be happy with it for now.

If I end up really getting into aerobatics and liking it as much as I think I will, I'll get something else. But for now, I'll be happy enough just to own my own airplane and spend LOTS of time flying!! =)

Picking it up on Thursday!
 
Axel, what airport are you at? I'll be keeping my plane at Compton. If you're close by, I'd love to check out your fast-back. I LOVE the looks of the fast-back and would like to convert mine at some point. But not sure if I have the skills to do it... LOL.

AX-O said:
Thanks Mike.

Brian,
a few comparison numbers for you since you asked about 180 vs 200 hp.

My plane:
-RV-4 air frame with fastback and rocket canopy
-sam james cowl and wheel pants
-engine plenum
-IOX-340 with electronic ignitions

-Full open throttle, leaned out rich of peak, 8500 ft msl gets me 189kts true (corrected/verified) burning about 9.5-9.6 gal/hr. I don't have all my fairings on yet and my horizontal stab angle of incidence is not where I want it yet. So I am hoping I can get to 190 KTAS after the changes.

-At my normal cruise (2650 rpm, fix pitch, cant remember MP), lean of peak, 8500 ft msl gets me 174kts true burning about 7.4-7.6 gal/hr.

That being said, all our air planes can't really be compared apples to apples. Some have electronic ignitions, some take painful approaches to reducing drag and drag cooling and some just build to plans.

Like Smokey said. If the motor is a good price, who cares. The only opinion that matters is yours. You can reduce some of the empty weight if you go to a fix pitch prop. If you go that route, pick a company that has experience making props for the pusher communities (i.e. Catto, etc).

Good luck.
Click to expand...
 
No worries!

1flyingyogi said:
Thanks for all the replies. Great info. That deal is a no-go, though. It's got a history of engine issues and compressions currently are 70, 65,66, 71. And although the paint looks great, I'm not crazy about the scheme.

But I ended making a deal for another -4 nearby. It's close to new, with 270hrs E/ AF, great condition. The only thing is it's got the O-320, instead of the O-360, which I really wanted. But for the price and with everything considered, I think I can be happy with it for now.

If I end up really getting into aerobatics and liking it as much as I think I will, I'll get something else. But for now, I'll be happy enough just to own my own airplane and spend LOTS of time flying!! =)

Picking it up on Thursday!
Click to expand...
Brian,
You won't be disappointed. My lightweight (925lb) 0-320 powered Four outperformed many 0-360 versions and surprised quite a few in 1v1"s. :)
Having flown them all and owned a Rocket my favorite RV is still the light, simple 0-320 powered RV4!
V/R
Smokey
 
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Wow, really?? I've read that from a few other guys too and am really surprised. How does the 160hp keep up or outperform the 180hp??

All else being the same, the weight difference of the O360 is only about 18lbs heavier right? So same AF weight, same prop, and only an 18lb weight penalty, wouldn't the additional 20hp be much better? Maybe not so much in cruise, but certainly climb, right? And for aerobatics, especially upline maneuvers, the extra hp would be a definite plus, right? Would the 160hp even have enough power to pull to a 90 degree vertical from level and maybe do a few rolls on the way up?

I'm picking up my -4 on Thursday. Can't wait!!!

Brian




smokyray said:
Brian,
You won't be disappointed. My lightweight 0-320 powered Four outperformed many 0-360 versions and surprised quite a few in 1v1"s. :)
Having flown them all and owned a Rocket my favorite RV is still the light, simple 0-320 powered RV4!
V/R
Smokey
Click to expand...
 
Outstanding video. Thank you Chris for posting
My airplane is a simple and light -4 . I have been flying it for nine years. I am not disappointed in the performance.:)
 
Nice airplane

Dayton,
I saw your -4 at the west coast formation clinic a few years ago, and you have a very nice airplane.

The all around performance and handling qualities of the light nimble -4 is hard to beat..
Cm
 
But why????

1flyingyogi said:
Thanks for all the replies. Great info. That deal is a no-go, though. It's got a history of engine issues and compressions currently are 70, 65,66, 71. And although the paint looks great, I'm not crazy about the scheme.

But I ended making a deal for another -4 nearby. It's close to new, with 270hrs E/ AF, great condition. The only thing is it's got the O-320, instead of the O-360, which I really wanted. But for the price and with everything considered, I think I can be happy with it for now.

If I end up really getting into aerobatics and liking it as much as I think I will, I'll get something else. But for now, I'll be happy enough just to own my own airplane and spend LOTS of time flying!! =)

Picking it up on Thursday!
Click to expand...

Flyingyogi,
Glad you were able to make your decision.
When comparing engine combinations in the model, there are plenty of variables as others have mentioned.
My question is;

What do you really want?
Top speed?
endurance/fuel burn
climb over mountains

After some airframe clean up, change to P-Mag, I recorded the following numbers using my "old-fashioned IO-320 CS"
167 its true
fuel burn 7.1 gph
24.5 square
climb at sea level 2500 sustained

Everything is a compromise. Speed, baggage, cost.
Fortunately, in an RV 4 it is ALL fun.

Daddyman
 
My empty weight is 1021. That sounds heavy by the official numbers on Van's website. But of all the -4's I've looked at over the past few months, I've never seen one under 1000lbs. What do all of your planes weigh?

Mine is simple with O-320, manual flaps and trim, steam gauges, Sensenich metal prop standard everything.
 
N359DM weight sheet

WEIGHT & BALANCE DATA

Make: Van?s Aircraft
Model: RV4 Serial # 4354 Registration # N359DM

Datum= 60 inches forward of wing leading edge. (L.E.)
Design C.G. Range = 15% to 29% of wing chord, or 8.7? to 16.8 inches from L.E., or 68.7 to 77.4 inches aft of Datum.
Wing L.E. = 60?aft of datum.
Main wheel, right = 60?aft of datum.
Main wheel, left = 60.3?aft of datum.
Tail Wheel = 237.5?aft of datum.

Aircraft weighed empty in level flight attitude.
Weight (lbs) Arm (ins) Moment (lbs. in)
Right Wheel 441 60 26460
Left Wheel 436 60.3 26290.8
Tail Wheel 56 237.5 13300
Total: 933 66050.8

CG=66050.8 / 933= Empty moment of aircraft 70.8? aft of datum
 
Weight of the Dream Flyer

1flyingyogi said:
My empty weight is 1021. That sounds heavy by the official numbers on Van's website. But of all the -4's I've looked at over the past few months, I've never seen one under 1000lbs. What do all of your planes weigh?

Mine is simple with O-320, manual flaps and trim, steam gauges, Sensenich metal prop standard everything.
Click to expand...

Mine weighs 993.
But to be fair, I've equipped it for IFR flight, with ILS, KI 155 dual radios, ADS-B in.
Got it at 1015, and put it on a diet.
Yanked outdated electronics (that saved some).
Bought a lighter battery when my old "red/pink" one died. Saved 18 pounds right there.
Light with starter when the old one died too.
So it looks like death has contributed to loosing weight.

Also in a previous post, I did not correct speeds for temp and pressure.

I can really feel the difference when I'm alone in the plane and slight less than full fuel. Elevation of home field is 85 ft. and initial rate of climb- just less than 4,000/ft/min



Daddyman
 
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