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0-360 on a 0-320 engine mount question?

rhill

Well Known Member
Has anyone used a 0-360/Catto three blade mounted by a longer(2") engine mount to counter Weight & Balance issues on a 7a tip up? If so what cowl have you used? what would you do differently? etc... I am not crazy about added weight, especially if it's rotating, I am even more apprehensive of aft CG as I have an hour in a 7 with two big guys and low fuel, Pitch sensitivity is disturbing.
 
I have on O-360 on a 320 mount on my 7/TU with a three blade Catto. I haven't weighed yet, but I suspect I'll be fine seeing as thought the 320 mount is designed with the use of a constant speed prop in mind. My overall engine/prop combo weighs less than the 320/CS combo.

I did have to have Will James make me a special length cowl, but it didn't cost any additional. I will have some "special" 'glass work to take care of at some point because of the additional length, but that can be dealt with easily enough.

I wouldn't change a thing at this point, and like I said, I do believe my WB numbers will be good...
 
Thanks Chad, What were the fit problems for the std Vans Cowl? 0-320 vs0-360? Did you use the Saber 2.25" ? Light or heavy crush plate? What
is your choice of ignition systems?
 
Reiley is right...the 235/320 cowl won't work, it's too narrow, and too short for a 360. I don't know anything about the std 360 cowl from Van's other than the fact that Gus told me the carb inlet scoop would need to be cutoff and re-grafted on the cowl in a more forward position. I never planned to use the Van's cowl, so Will James just made me one that would work. The way I understand it tho, is that either cowl would need to be lengthened to work with a 360, and the SJ cowl scoop didn't need to be modified.

I used the standard 4" extension from Saber for the 360/Catto combo. Works fine. The crush plate is the 7" one, 1/2" thick.

I have one mag, one Lightspeed Plasma II+.
 
I would think that there would be enough trim material on the 360 cowl not to cause you any issues. Even on the 235-320 cowl there is a lot of material to trim off the back when fitting the cowl. I do know one thing you will like is having the 2" 's of extra room behind the engine. You can absolutely get to everything with ease. :)
 
Thanks Guys, I will check with Van's, Sounds like a 0-360FI cowl with a carburetor scoop grafted on the right location might be the way to go.
I would think Van's would have thought of this and worked something out by now.
I waited ten years for a Lycoming to fall off a turnip truck ,I never dreamed it
would be a 0-360, all my plans are based on 0-320, light weight, Catto three blade . I will trade off 21 extra pounds/20 to 30 more ponies for more fiberglass
work any day, I cant help thinking there is more to this than that.
 
IO-360 Engine on 320 mount

Picking up a long-dormant thread.

I am building a Vans RV-7A with a Superior XP-IO-360-A1HC2 engine and a Catto 3-blade fixed-pitch prop. I purchased the Vans finishing kit with the 360 engine mount (WD-739-PC), 360 cowling, and the spinner for the wooden prop. I am also getting the 2.25" saber extension.

Saber told me that the plane is likely to be tail heavy and recommended the 20-pound crush plate on the prop. It pains me to be building light and to buy a spiffy light composite prop and then put 20 pounds of crush plate on to fix the CG.

I've seen this thread about using a 320 engine mount to push the 360 engine forward and improve the CG. One of my friends met a Vans engineer at a fly-in and understands the engineer is doing this on his plane. But another builder tells me he called Vans and was told Vans has no cowling that will work with an IO-360 engine that far forward.

This thread is old and I'm wondering what the latest news is. If you have built a RV-7 with an IO-360 engine on a 320 engine mount, I'd like to hear how it worked and whether you had cowling issues.

Thank you,

David
 
Has anyone mounted a Concord RG25 on the firewall of their RV 7/7A to address the aft CG issue when using a light weight Prop? Seems like a more useful way to move the CG forward, than a crush plate. Assuming it fits of course.
Bob Bisbee
 
Has anyone mounted a Concord RG25 on the firewall of their RV 7/7A to address the aft CG issue when using a light weight Prop? Seems like a more useful way to move the CG forward, than a crush plate. Assuming it fits of course.
Bob Bisbee

The original RV-9 plans were for a battery tray that fit a standard 25 size battery on the firewall because the Odysee wasn't in common use then, so it could be done.
If you do the W&B computations though, I think you will find that it helps much less than a weight out on the front of the prop. because the firewall is not very far fwd of the CG by comparison.
 
Not flying yet but I've done it on RV7

Vert induction io360 parallel valve, three blade CS MT. O320 mount, vans O360 cowl had to graft between 1-2.5 inch on rear of cowl halves (actually 3 inches all round then trimmed back to fit length.

Was originally intending sensi metal 2 blade with future upgrade to 3 blade catto and that was the purpose. MT weighs same as sensi so maybe a tad on the forward side of W&B full fuel no baggage or Pax but won't know for sure until it's weighed.

Vans said no, I signed a waiver, other people had done already at that time or added spacers between engine mount and FW. I'm comfortable with what I'm doing, I wouldn't necessarily recommend it for every builder. It wasn't an insignificant amount of extra work, mostly due to cowl extension. If you could order an extra length or uncut 360 cowl from Vans or aftermarket that would cut down the work. Not sure how it would go with horizontal induction setup. The room behind the engine is much more manageable. I couldn't stomach bolting on dead weight to fix W&B after the fact when it was very obvious there was going to be an issue that could be fixed during the build process.

If a subsequent owner ever wants the aeroplane to get re-engined to IO360 Angle Valve/horizontal induction and or Harzel metal CS, new cowl and engine mount will be required... But the entire FWF will need to be redone at that point anyway. Same as switching from O320 to O/IO360.
 
I have the 20 lb Saber plate and would do it again. Empty weight, without paint is just over 1100 lbs. If I ever change my engine from solid crank and go constant speed, it won't require a new engine mount.

And, I can drop 11-12 lbs from the firewall by replacing the PC680 with an EarthX.
 
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