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n38139

Well Known Member
I was considering selling my -4 and buying a -8 for a little more room and bigger engine. I flew an -8 that was for sale and it didn't handle as well as my -4 or have much better performance.

Sooooo my question is what is the best 180 to put in a -4 and is the expense justifiable when compared to selling and stepping up into a -8 with a larger engine. I have an O-320-E2D. I would like a constant speed prop.

The debate for me is really not having a larger airplane but more climb and overall performance.

thanks,

Steve :confused:
 
I was well into building my RV-4 before I ever got a ride in one. The very first ride I had was in an RV-4 with a 180 horse motor and a constant speed prop. I have never forgotten that ride. I may be biased but I think that was probably the best performing airplane I've ever ridden in. He also didn't seem to have to fret over backseat weight like I do. If space isn't a huge concern to you and you're mostly just looking for performance, it's a good way to go.
 
RV-4 w. 180

Hi,

I have an RV-4 with O-360-A1A and a FP wood prop. It weighs 964lb empty with oil and the CG ~17%. I don't have any aft CG problems with pax, though it noticeably changes the handling. I can climb at 1800fpm solo if I wish, but the RPM is way back and I generally climb at 110KIAS/24-2500rpm and get well over the 1000fpm still. I've flown RVs with metal CS props, and I notice the T/O and climb improvement, but I also notice the extra weight on the stick. 75% cruise is ~172KTAS. I think the ideal -4 might be a 160hp O-320 with WW 151 CS prop.
 
Its doable

n38139 said:
I was considering selling my -4 and buying a -8 for a little more room and bigger engine. I flew an -8 that was for sale and it didn't handle as well as my -4 or have much better performance.

Sooooo my question is what is the best 180 to put in a -4 and is the expense justifiable when compared to selling and stepping up into a -8 with a larger engine. I have an O-320-E2D. I would like a constant speed prop.

The debate for me is really not having a larger airplane but more climb and overall performance.

thanks, Steve :confused:
Click to expand...
Yep the RV-4 handles better in my opinion and I think looks better. The RV-8 has more room and gas, no doubt.

I had a 150HP O320 and a hartzell constant speed prop on my RV-4. Not sure you are going to get that much more performance.

However if you love you RV-4 consider selling your whole FWF and buying a O360/hartzell BA prop. (Do you have the long cowl 4" prop extension or the shorter one.) If you have the short cowl you should be OK, other wise plan on $1000 for a new cowl and spinner. Suggest you look at James Aircraft cowl and sealed plenum, good for 8-10 mph more speed.

I figure you are looking at $30,000 for the upgrade minus the sale of you current engine/prop.

I recommend Mattituck for a O360 and Vans for a BA Hartzell. You probably don't want to convert to fuel injection (FI).

As I said you will need a new baffle and maybe cowl. At min the cowl scoop will have to be cut off and changed going from a 320 to 360. If you have the long cowl you will need to get a short "constant speed" cowl, which is not a bad thing. The new cowls are better than Van's old gel coat solid laminate jobs.

The other thing you could do is sell your RV-4 for another RV-4 with a 180 or 160 hp with a constant speed prop.
 
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$2000 per knot...

I have helped three RV buddies convert good flying, reliable, well proven 150/160HP RV4's to 180HP C/S.
Three issues came to bear. The 180HP uses different baffling, exhaust and is physically bigger by several inches requiring a new larger cowling with a bigger air scoop. Second is your exp airworthiness certificate. In some peoples opinion changing engines is a major change requiring an inspection and re-certification. On 2 of them I helped with no paperwork was done and the third guy wished he hadn't called the FSDO. Overall the change cost $2000 per knot of cruise speed gained over the 160HP. Climb is obviously improved as is STOL. Cruise on all three was around 165 knots true at 8500'. The conversion grounded the airplane for about 2 weeks, mainly working on it part-time.
My recommendation is to use the extra money to buy alot of 100LL, enjoy what you have and save your pennies for an HR2. Having both an RV4 with 160 HP and an HR2, the Rocket rules!

RR
 
Steve,
I have the 180 / CS prop on my -4. I have the Hartzell B/A on mine as well. I also have the tip tanks for a total of 50 Gallons. Mine has a slider and is quite heavy @ 1109 LBS. If I'm light and on a standard day I get off in about 300' to 400' and never do less than 2500 FPM. I do wish I had purchased the Aero Sport prop as it is lighter & faster though. I do have some performance mods as well. The 0-360-A1A weighs in @ 9 LBS more than the O-320 A1A. All RV's are fun, some are more than others. It all depends on what you want to do with yours, as well as who you fly with. I likely can't turn with the light ones, but they don't have the vertical either. I do like to mod mine some.
Gary
 
Were it mine, I would consider upgrading to the 160 0-320. (easy to do with your existing engine). All in all, the 320 series engines are IMHO the best series ever produced by Lycoming. Very few Service Bulletins and AD's, good on fossil fuel, can be converted to constant speed, less expensive to overhaul.

Bumping the compression to 8.5:1 will get you to 160 and still enjoy the benefit of 2000 hours (subjectively) TBO. You could go higher in compression, but run the risk of decreasing the life of the engine due to increased bearing loads caused by higher cylinder pressures.

Just my 2 pennies

Allen
 
how different would it be..

Steve,
I suspect the reason you didn't like the RV-8 was because it has a big engine/prop combo hung way out on the nose to handle the "back seat bubba factor".

If you do the same to your RV-4, you may not like that either. So, plan B:
How about getting one of those engine hot rodders to breathe a little more 'umph into your 320? Say 170 or 175 hp. I suspect ( but don't know ) that it could be done safely. Then add the previously mentioned WW prop and maybe those Dolly Parton wheel pants and a plenum. Maybe, you could get most of the performance without changing the feel of the plane too much.

Or, plan C: Say screw the whole thing and go buy Milt's Rocket and blast off into the Stratosphere :). You better hurry though, If I hit the lottery this weekend, I'll beat you to it ... :).

John
 
Thanks for the replies

I guess I will just stick with what I have. Thanks for all of the input.

Steve
 
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