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  #1  
Old 03-18-2016, 12:32 PM
1flyingyogi 1flyingyogi is offline
 
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Location: Long Beach, CA
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Default LIO-360 on RV-4

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
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  #2  
Old 03-18-2016, 01:19 PM
Michael Henning Michael Henning is offline
 
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Location: Nashua, NH
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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.
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  #3  
Old 03-18-2016, 01:37 PM
BenNabors BenNabors is offline
 
Join Date: Mar 2014
Location: Alabama
Posts: 127
Talking Horsepower = fuel burn rate

Quote:
Originally Posted by 1flyingyogi View Post
What about fuel burn?
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? Not me.
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  #4  
Old 03-18-2016, 04:20 PM
Michael Henning Michael Henning is offline
 
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Location: Nashua, NH
Posts: 536
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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.
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  #5  
Old 03-18-2016, 04:32 PM
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AX-O AX-O is offline
 
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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.
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RV-4 fastback thread and Pics
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  #6  
Old 03-18-2016, 05:32 PM
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Toobuilder Toobuilder is offline
 
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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.
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WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.

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  #7  
Old 03-18-2016, 08:37 PM
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smokyray smokyray is offline
 
Join Date: Jan 2005
Location: TX32
Posts: 1,891
Default Left hook...

Quote:
Originally Posted by 1flyingyogi View Post
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
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....

Last edited by smokyray : 03-18-2016 at 08:48 PM.
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  #8  
Old 03-18-2016, 09:00 PM
Michael Henning Michael Henning is offline
 
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Location: Nashua, NH
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Axel,
Altitude is msl, speed is true.
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  #9  
Old 03-19-2016, 09:13 AM
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AX-O AX-O is offline
 
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Quote:
Originally Posted by Michael Henning View Post
Axel,
Altitude is msl, speed is true.
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.
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RV-4 fastback thread and Pics
VAF 2020 paid VAF 704
The information that I post is just that; information and my own personal experiences. You need to weight out the pros and cons and make up your own mind/decisions. The pictures posted may not show the final stage or configuration. Build at your own risk.
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  #10  
Old 03-19-2016, 11:22 PM
F1R F1R is offline
 
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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.

Last edited by F1R : 03-19-2016 at 11:25 PM.
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