0-300 for RV's?
 

Does anyone have information concerning if a Cont. 0-300 will fit under an unmodfied RV cowling? What about engine mounts? Thanks for the help.

No and Why?
 

I am sorry I don't know of anyone but.......

Why?

I am just curious. What is the argument to use this engine. I know it's a 145HP 6-banger that is out of production used in C-170/172's and smoother than a 4-banger, but all that extra work? Even if it would fit why?


I say old out of production engine and an untraveled journey that (I know of), means this is a poor choice. Are these engines cheap to overhaul? My guess is they are not cheap. I know the O-200 has some expensive parts.

The Lycoming is the obvious choice and even if someone gave me one I would not use it, but more power to you (pun intended :D ). This of course doss not consider possible )likely) technical objections, meaning it just does not fit with out major modification.

Cheers George

I wouldn't suggest this engine, they rarely make rated power, and the overhaul costs are high. Also they tend to leak a LOT of oil. 50's technology at it's best :). As for it fitting under the cowl? Most likely would, but the mount would be a thing to see.

An 0-300 puts you a little farther into experimental land. It can be done (I've seen one), but you'll need to fabricate your own engine mount. I don't remember if it requires a custom cowl or not.

If you ever went to resell the airplane, it might have a big of a "freak" stigma, so you should consider that too.

Also, most builders are adding more HP, not less.

Why the 0-300?
 

Here is an answer to some of the questions;

1) 6 cylinders are smoother than 4.
2) If nobody has done it so it would be fun to be the first.
3) That is the great thing about being "experimental" if I wanted to do what everyone else does, I would buy a C-172.
4) The RV is already the closest thing to a production A/C that you can get, I want to keep the "experimenting" in EXPERIMENTAL.
5) I want to us MOGAS to keep costs down
6) I am an A&P and thus and not worried about overhaul cost
7) The RV-9 would be the airframe of choice for a 145HP engine, sipping 6 GPH in cruise while giving you an honest 120 KT cruise speed.

These are just a few thoughts that I am kicking around.

I'll take a crack at a few of your above notes with my usual "no holds barred". Please don't take offense at my comments if they sound harsh, I'm just not good at sugar coating or being a politician! That being said, it almost sounds like your mind might be made up, and if so I sincerely wish you good luck. Happy Holidays,
Stein.

True to an extent, but getting them both being well balanced it's honestly hard to tell.
Depends on what you mean by "fun". If Tons of extra time, extra pain in the rear fabricating your own mount, baffling, intake/FAB system, oil cooling, and maybe modifying the cowl if "fun", the that's great! And...these things usually end up costing more money as well.
Once again, depends on how much you want to be "experimental". Not too much if you settled on the RV...I'm guessing because they are a great bird!
So...the question is if you detest the masses building something similar, why pick it and not just "Experiment" from the start? I'm guessing the obvious attraction to you was the unbeatable performance of the RV's, affordability, etc.. There is a reason so many people have built them you know.....and....those combinations of performance, cost, etc... have come from the majority running a proven combination of systems.
This is an option with nearly every engine you put on the RV's, including both the -320's and -360's so that's a moot point.
Another moot point. It doesn't matter whether you're an A&P or not, anyone can overhaul and engine for their experimental. The parts will cost you the same no matter who overhauls your engine, A&P or not. Parts for current production Lycosaurs are cheap, parts for the out of production 300's are going up all the time.
Or, you could put a -235 on the front of it, go just a lot faster on even less fuel burn....like several other -9 drivers have done! Check Van's Website for performance figures with the 118hp or 135hp engine installed.

I really don't mean to sound like I'm flaming you, I'm not. Just that it's never as simple as it sounds using a totally different setup on these RV's with much success or improved performance/cost. Anyway, if you love tinkering and don't mind adding a lot of extra time and probably money to your project then jump in. If your goal is to get the airplane done and in the air, the choice of that engine will certainly work against that goal.

Sounds like you.....
 

Hey no argument. If being first is important, different, experimental and all than it sounds like you got your reasons:


A few things I would add or point out is:

>O-300 overhaul parts are more expensive due to low volume (regardless of labor)
>The Cont is not more (or less) efficient than a Lycoming (HP vs. GPH)
>The 150 HP Lyc can burn 6 GPH at approx 55% power
>No one has done it (a plus for you as mentioned)
>The 150 HP lyc is MOGAS capable

For the RV-9A solo:

I think you got your speeds a little low, looking at Vans data a 118HP at 55%/75% will give you 131/145 kts.

A Lyc 150HP at 55% power burns about 6 GPH

Van does not give 150 HP performance #'s, but a 160HP RV-9A would be about 2.17% faster.

Using the Lyc O-320/150 hp:
55% your speed is (@ 6 GPH) = 144 Kts
75% your speed is (189/1.0217)= 185/1.15 = 161 kts
Top speed is (197/1.0217)= 192.8/1.15 = 168 kts
(from Van's 160HP data adjusted for 150HP)

Of course you could go to a 160 HP Lyc and get all the same benifits of the 150 hp except you will have better performance. THe 160 hp of course is not good for MOGAS with the HC pistons. Still you can throttle back or fly higher and still get 6 GPH with a 160 hp engine.

Anyway good luck, and if you decide to do it post some pictures, G

There's a Franklin 125HP 4 banger advertised for sale at POC... There's something that probably hasn't been done before!

If you were going to go to all the trouble to mount a Cont 0-300 six cyl engine, then you would be FAR better off to just use the I0-360 Cont six cyl engine that makes 210 hp and is virtually the same weight.

Just my 2 cents!

First, second, or third; it sounds like good enough reason for me. Have fun.

It's your plane, build it the way you want it.

Good luck and keep us posted on how it comes out.