VAF Forums

VAF Forums (http://www.vansairforce.com/community/index.php)
-   RV-4 (http://www.vansairforce.com/community/forumdisplay.php?f=9)
-   -   RV 4 Engine selection ? (http://www.vansairforce.com/community/showthread.php?t=145617)

Larry DeCamp 01-11-2017 07:19 PM

RV 4 Engine selection ?
 
I need to decide what engine for my 4 project. I am not a horsepower / ROC / Speed seeker. I am relatively anal about smoothness and am convinced a big engine loafing is more desirable than a small engine working harder to fly the same speed.SO, there are three options for me:
* 340 from stroke increase
* 340 from bore increase
* 360 pretty much stock with maybe 15lb weight penalty
Your comments from EXPERIENCE would be appreciated...Larry

AX-O 01-11-2017 09:13 PM

The 340 is not the smoothes motor and depending on the prop combination there are harmonic issues. Not sure how you came up with the 340 as being smooth compared to others. But i can tell you my 0-320 on my previous rv-4 was way smoother than my IOX-340 in my new rv-4. To the point that i thought something was wrong. Both engines/props were dynamically balanced.

I have had issues with the spinner bulkheads and the prop wearing on each other due to the vibrations. Craig Catto gave me some bevel (spelling?) washers and told me to keep a close eye on it because it is a major problem if it keeps happening. He then told me about the harmonic issues a certain rpms (from test data collected) and cautioned me to stay away from those at continuous rpm operations.

In 100 hrs i have had broken 3 exhaust hangers and found a crack on the exhaust flange on #4.

Hope that helps.

Christopher Murphy 01-11-2017 10:48 PM

Smooth
 
A 320 with a smooth wood prop on a light airframe makes a great airplane. The 320 is pretty bullet proof.

Cm

ArlingtonRV 01-11-2017 10:50 PM

I had a 160HP O-320 with a metal Sensenich prop in my -4. It was reasonably smooth, but could be better. I did not have it dynamically balanced. I ran a 3 blade Catto on it for a while and that was very smooth.

Jetj01 01-12-2017 12:39 AM

No question for me- Lyc O-360A1A
 
Hi Larry,

I have owned four -4s. The first three I bought flying and three had O-320s two with wood props (Sterba and Demuth) and one with a metal Sensenich. I finally built my own -4 after a venture with an RV-8, RV-6 and a Rocket. With those hours and experiences under my belt I went with an RV-4 with an O-360 A1A, carbureted, and Hartzell 74 inch Blended Airfoil. I've had it balanced and LOVE the combination. And now with my EMags it's even smoother. At cruise I run 2350 RPM which keeps the vibration and noise down and can routinely see 200+ mph at 8gph. Flying formation with my O-320 neighbors I can see 6-7 gph at 170-180 mph TAS. I do not fly 'hard' aerobatics in my -4, usually limited to 3-4 Gs and do not have an inverted system. With the energy my airplane maintains I can do a vertical maneuver (loop, Immelmann) from level flight and gain energy! I also LOVE the combination for formation flight and pattern energy control. I'd venture to say once you've gone constant speed in an RV, it's hard to go back to fixed. I used to fly my -4 800 miles a week from TX to KS and back and used to look forwArd to the flight (good seats help) and consider the -4 my perfect all around best airplane......for me. The O-360 'fits' well and gives you a 'no excuses' airplane when built for YOU! Enjoy the adventure!

Tomcat RV4 01-12-2017 08:26 AM

I have RV 4 with STOCK rebuilt Subaru 2.5 Legacy ,with SDS control for fuel injection,ignition, (stošk) along with stock starter,alternator.I used 0-320 mt that came for RV and made own adapters from Suby to mount so a 0-320 could be reinstalled with standard mounts.we have our air worthiness and are currently taxi -testing.However hard to find calm days this time of year in Northeast for first flight.Using PSRU from Air Trikes in Canada,along with their 3 blade ground adjustable 3 blade prop.Using rad underneath,similar to Ross at SDS, my ductwork aluminum,his made neater with fiberglass..Give me e mail an would photos.Tom (have not had time to figure posting photos here)

WAM120RV 01-12-2017 09:40 AM

Look at the UL power engine
 
O.320 with Sensenich FP on mine and TVs not bad.

However, as I will need another engine for my 9 I am considering a UL power engine. Much lighter than a lycosaurus, and more power, plus 6 cylinder which should make it smoother. One has just been fitted to a 4 in the states.

sblack 01-12-2017 12:14 PM

Quote:

Originally Posted by Jetj01 (Post 1141200)
Hi Larry,

I have owned four -4s. The first three I bought flying and three had O-320s two with wood props (Sterba and Demuth) and one with a metal Sensenich. I finally built my own -4 after a venture with an RV-8, RV-6 and a Rocket. With those hours and experiences under my belt I went with an RV-4 with an O-360 A1A, carbureted, and Hartzell 74 inch Blended Airfoil. ......he O-360 'fits' well and gives you a 'no excuses' airplane when built for YOU! Enjoy the adventure!

I have heard that having a CS on a -4 moves the CG quite far forward, enough to increase the pitch forces so that you no longer have the nice light handling. But you seem to be very happy. Do you notice a big difference between the wood prop airplanes and the 360/CS in terms of pitch forces? Or do you always fly with a fat guy in the back seat? :p

springer 01-12-2017 12:36 PM

O-360-A1A with Warnke FP on my -4. 1 mag 1 LSE. Very smooth and significantly out performed my O-320 -4 flying partner.

Michael Henning 01-12-2017 05:33 PM

IO-360A1A pumped
Up to 200 HP. With the whirlwind prop, my empty weight cg is within 1/2" of where Van recommends. So I still get the light handling, with the added vertical performance. Plus, I had the prop balanced so it is turbine smooth with the 3 blades.


All times are GMT -6. The time now is 10:50 AM.