Which engine

[coodem]

New to the forum and just wanted to thank you all for making it such a great database of info.

I have spent a long time looking into which aeroplane to buy/build. I thought I would end up with the Australian Jabiru J400, as it has 4 seats and is relativley cheap.

Then I did reseach and although it can carry 4 people, the likleyhood of finding such small/light people is unlikley. (Not planning on any kids for a while)

Then I had my eye set on the RV7a, but it seems unlikley it will ever get the aerobatics certification in the UK due to its Spin characteristics.

So now Im left with the RV9a. Pretty much the same as the RV7, apart from the smaller engine and being more of a tourer.

Now the problem is finding a suitable engine. Can't seem to find much.
So far I seen the GNX 320, a Aero Sport Power O-320 and Mattituck.

I have chosen "experimental" engines, due to me wanting a brand new engine, as apposed to an overhalled Conti/Lycoming. I hear Superior are/were thinking of doing a 320.

Has anyone got any other ideas/suggestions.

The other reasons I have chosen/looking into the above engines is due to them having a possibilty of having inverted oil system and Injection

 

[RScott]

Welcome to the forum! I know the folks on here will do their best to be helpful.

First, a question: It sounds like aerobatics is out of the question, so I have to ask, why do you want inverted capability for a -9, which was not intended for aerobatics?

Both Mattituck & Aerosport have good reputations & I doubt you will find much of a savings with someone else. You might think about this: As soon as you start flying with that new engine, it will be a used engine. I'm second guessing from your post, but it sounds like money is an issue. If I am right, you might want to rethink the question of a rebuilt. At Aerosport, they build new engines just the same way as rebuilts. They can make the same mistakes on either kind, so new is no guarantee of perfect assembly work. Haven't heard of the GNX 320 so I can't comment.

Talked with a guy at Van's last weekend who had a Subaru in his RV & with the reduction drive & everything else he could have had a good Lycoming rebuild that would have weighed 50 lbs. less, so at least for me, I don't see that as a desireable option. He did say he saved a gallon per hour on fuel & burned car gas, which might be more of an issue in the UK.

I know others on this forum will have some better info.

RScott
RV-9A very slow build wings

 

[pierre smith]

Lyc

My 2 cents worth.

I have a friend with a supercharged Eggenfellner engine in his new RV 7, a beautiful airplane. He only does 165 MPH or so at 35 inches MP!! I saw this myself because I was in the airplane giving him a BFR. He also only burned 7.2 GPH from Memphis to Ga averaging 162 MPH (his usual speed) so I told him that I just didn't believe that he was making the horsepower or he'd be burning more gas. His performance seems like there's maybe 140 HP or less.

I can't understand the big problem with having a Lyc. There are thousands of them worldwide with a proven record....oh well....to each his own,

Welcome to the forum,
Regards,

 

[coodem]

I forgot to mention that it is possible to get aerobatic certification for the RV9a, but not the RV7a. Hence the need/want for the inverted oil system.

As to the 2nd hand/rebuilt engine, I agree that they are the same, but in the past been unlucky when buying such things. I would just feel reassured and at ease with a new engine. But might still be persuaded should a cheaper alternative come along. But for the time being, the differance in cost between a new superior and a rebuilt Lyc 320. i would pay the little extra and get new.

RScott, thanks for the reply. I will give Mattituck & Aerosport a call as well and see what sort of money they would be. I have since found out that superior have launched the 320 and have already sold 4 in the UK (Another reason for superior is they have an agent in the UK, just up the road from me, so would have no probs with warrenty issues, as the have 3 years)

 

[Guy Prevost]

I forgot to mention that it is possible to get aerobatic certification for the RV9a, but not the RV7a. Hence the need/want for the inverted oil system.

Wow! That's really strange! Even if you can get aerobatic certification for the RV9a, it is not designed for aerobatics. Van's never intended the 9's for aerobatics and it was not engineered for those loads. I doubt the certification alone will hold it together if you overstress the airframe.

It sounds like you have a real disconnect between reality and bureaucracy on that side of the pond. (I thought it was bad here...)

It's none of my business, but I would be very hesitant to pursue this path if I were you.

Cheers,
Guy

 

[frankh]

Its not so bad

The beurochracy in the UK that is....But flying anything will cost you an arm and a leg.

A couple of thoughts from an Ex pat Brit...Why not build the 7a get it certified and then do any aerobatics you want?...Who's gonna know?

The exchange rate is that you you will (should) get an incredible deal right now....Last time I looked the rate was $1.85 to 1pound...It used to run in the 1.3 to 1.6 range.

Both of the Lycoming clones (there really is only 2 types...an ECi or a Superior engine, the rest is dependant on who assembles the motor.

Both of the clone engines will run quite happily on premium autofuel.

I never got an adequate answer to convice me that a water cooled engine in an RV was as fast...I.e did not produce significantly more cooling drag.

I have yet to see an engine fly as fast sipping as little fuel as a Lycoming when run lean of peak. I don't believe the injection system on any readily available will allow LOP operation.

Having flown 400 hours behind an auto conversion, I finally saw the light and stuck a Lycoming clone in mine.

Frank

 

[frankh]

********I don't believe the injection system on any readily available will allow LOP operation.******


I meant any automotive conversion not being able to be run LOP

Frank

 

[Dave_Boxall]

Aerobatic certification for the 9A

I forgot to mention that it is possible to get aerobatic certification for the RV9a, but not the RV7a. Hence the need/want for the inverted oil system.

I'm in the UK and I'm sure that you'll never get aerobatic certification for the 9A. Several people are pushing to get the 7 certified though, so that may happen.

I can't help much on your engine choice as I'm just about to hang one of those strange Wilksch diesel things on the front of my fuselage. That probably makes my engine opinions suspect!


Dave

 

[coodem]

Looks like I have been mislead along the way. Been told the "A" after the model was for aerobatic, and was told only the 7A has not been certified.

So what does the "A" actually stand for?

Guess it means Im back to the 7a, But it would be so tempting to do aero's, knowing the aerplane is more than capable.

This explains why I have only found articles about the 7a's aerobatic capabilities

Dave, can you tell me more about your diesel lump. What sort of Hp, PFA?? Are they happy with it. What does it weigh? Where will you be sourcing it?

Thank you all for clearing the "A" up

 

[Mike S]

A is the designation for a nosewheel.

Used when there is an option or tail or trainer--oops, I mean nose wheel

Note the 3 and 4 only come in tail, and the 10 only in nose, thus no -a for them.

Mike

 

[n2prise]

Engine choices...

It sounds like things are coming together on this thread. Let me finish it off with the basics on my RV-9A with an ECI O-320 160 HP engine built by Penn Yan Aero. The thing here is to buy an ECI engine, no matter who builds it. Get the Titan cylinders with the Nickel-Carbide coating in the cylinders for better wear and rust-proofing. You can get the engine with low-compression 7.5-to-1 pistons for 150 HP and use autofuel... OR... you can get it with 8.5-to-1 pistons for 160 HP and use AVGAS 100 low-lead. One other thing to note, the ECI crank case has several advantages over the Lycoming. The oil galley has provisions for spray nozzles to improve cooling of the pistons and improve the oil flow along the cam shaft. The second feature is a dowel pin and socket arrangement that prevents the two halves of the crank case from shifting longitudinally. The Lycomings can do that shifting and as a result leak oil from the centerline gasket easier than an ECI engine. There are also machined recesses and O-rings around the transverse bolts in the crank case to minimize oil leakage around those bolts.

My RV-9A cruises at around 6 gallons per hour flying above 10,000 feet on cross-country flights. RV-9 and RV-9A airplanes love it up high due to the Roncz airfoil wing design. The longer wing span of that wing is what disqualifies the RV-9 and RV-9A from doing aerobatics. With the longer wing span, larger tail feathers had to be built to match. The larger RV-9 rudder is now standard on the RV-7 to make spin recovery much better. That may be where you got the idea the RV-7 was not intended for aerobatics. I saw a few older RV-7's at Oshkosh this year with the smaller original -7 rudder, but all the RV-7 and RV-7A kits today come with the RV-9 rudders. Van's offered all the older RV-7 and -7A builders the new rudders for free for safety reasons. I asked one of the pilots at OSH this year with the small rudder still on the plane why he had not changed it out. He said he had the rudder kit, but just had not built it yet since he does not do spins with his RV-7.

The RV-7, -7A, -8, and -8A all come with the same aerobatic wings and tail feathers. The RV-8 and -8A still use the smaller rudder, since the narrow fuselage (tandem seating) does not limit rudder authority in spin recovery as much as the RV-7 and -7A which have the wider fuselage (side-by-side seating).

The other thing about the aerobatic airplanes, they all have tapered horizontal stabilizers and elevators. The RV-9, RV-9A, and the RV-10 all have constant chord horizontal stabilizers and elevators for more surface area back there and positive control behind the longer main wings up front. The RV-9 and RV-9A wing span is 28 feet, and the RV-10 is 31 feet.

There are a lot of RV-6, -7. & -8 airplanes out there with 180 HP and 200 HP engines going over 200 MPH, but burning a lot of gas to do it. I find that I can get up higher than those guys with the aerobatic wings, find better tail winds, and burn less gas and not arrive too much behind the guys with more horses up there. With the longer wing span, the 160 HP RV-9A can climb very well compared to the shorter wing RV's with 180 HP up front, and do it on less gas. As for the top end max speed Van's published on the RV-9 and RV-9A, been there, done that doing 193 MPH at 1,000 feet MSL. With the 160 HP engine, I can go "over square" on the power settings since O-320 the engine will not over-stress my Hartzell constant speed prop. To get the 193 MPH, I was turning 2,300 RPM at full power (28 inches of manifold pressure) to get the 193 MPH on a high-speed pass down low about 200 feet above the runway at my local airport. Granted, you cannot do that very long since the engine will get overheated. That does not even consider that the fuel burn doing that is around 11 gallons per hour through the engine. Now you know why I like to get up high, lean the engine, and cruise at 160 MPH true airspeed.

And the last thing to note, the guys at Van's all want to fly in the RV-9A or the RV-10 when they go to the big regional fly-ins or Oshkosh where Van's sets up their exhibit booth.

You will find my story of construction of the airplane, and all my flights documented on my web site www.n2prise.org with lots of photos and some video movies, including arrival and departure from Oshkosh this year. You can also see the RV-8 with an ECI O-360 180 HP engine that is being built by my hangar mate. I am coaching him during the construction and posting his process on my web site. Look for Wendell's RV-8 project from my home page to learn about that.

Jerry K. Thorne
East Ridge, Tennessee
RV-9A N2PZ Hobbs = 207.3 hours
www.n2prise.org

 

[Norman CYYJ]

I disagree with you about the RV6 and 7 not flying high. I fly between 13000 and 18000ft all the time in my RV-7 with 180 carburated fixed pitch prop, with a TAS of 170kts and a fuel burn of 6.2 to 7.3 gph at those heights. My climb rate at 20,000 ft is 450 to 500 ft/min and the highest I have had it is 25,540ft. I have cruised it at 21,000 for 3 hours and it handles just fine. These speeds are all WOT and lean of peak.