Marty d's CH-701 build log

[sfGnome]

That is really neat. I’ll have to remember that. 

[Marty_d]

Made the mounting bracket for the oil cooler.  It fits on the two spare M10 holes on the gearbox.   I thought it could be top mounted but there's too much flex in the vibration isolators, so I'll have to find a way of bracketing the bottom too, probably to the radiator front mount.

 

[Blueadventures]

22 minutes ago, Marty_d said:

Made the mounting bracket for the oil cooler.  It fits on the two spare M10 holes on the gearbox.   I thought it could be top mounted but there's too much flex in the vibration isolators, so I'll have to find a way of bracketing the bottom too, probably to the radiator front mount.

 

This is how my oil cooler has been mounted and no issues 337 hours so far.

[Marty_d]

Thanks Mike - so no rubber hasn't caused any problems with vibration?

 

[Blueadventures]

1 hour ago, Marty_d said:

Thanks Mike - so no rubber hasn't caused any problems with vibration?

 

No not at all.  Another oil cooler bracket on another R912 that I made.  All brackets use 32mm by 3mm flat aluminium bar.  I did fit a layer of rubber where the oil hose is in contact with the lower cowl; not installed when phot taken but on before first flight.

Edited May 21, 2023 by Blueadventures

[Marty_d]

Still trying to shoehorn the radiator and oil cooler into the cowl and getting there.

But on the long weekend just gone I had to take a break from plane work and install a toilet in the shed. Winter nights are getting a bit cold to go outside, especially for the missus. 

I did it backwards and put in the loo before the surrounding walls; which does make it a very spacious toilet,  but on the good side, gives you a good view while standing...

[sfGnome]

Good thinking, 99! I’ll bet the installation was a whole lot simpler without walls getting in the way (and you never know, you might get around to adding the walls some time in the next decade or so… 🫣)

[Marty_d]

I don't think SWMBO will wait that long. She's already choosing vanities so I'll have to wall it in, so I can put water supply and drain pipes through the studs.  Good news is though,  I only have to plaster and paint the inside (for now.)

[IBob]

The popular 1930s (?) book, The Professional, is intended as a humorous address... but also contains all the solid practical advice you'd ever need to site and construct a longdrop. Or a row of them (the family 3-seater etc). As this is what the book is all about.

Factors when siting included putting it out past the woodstack: since the ladies don't like to announce where they are actually going, they can say they are just going out to get some wood. and that way the woodbox always stays well topped up.
Clearly you missed the opportunity there, Marty......but you may still find you are required to add soundproofing....)

[facthunter]

Wouldn't the oil cooler be better not attached to the engine at all? There's a hell of a lot of vibration where that's located.   Nev

[Marty_d]

It's a long time since the 1930's Bob - my demure bride has no problem telling me where she's going. And sending me to the woodshed at the same time.

[Marty_d]

1 minute ago, facthunter said:

Wouldn't the oil cooler be better not attached to the engine at all? There's a hell of a lot of vibration where that's located.   Nev

Seems to be a popular spot Nev.  Other option is on a welded plate on the engine mount,  but that requires a separate NACA inlet, duct and shroud. 

[facthunter]

There has to be a risk of cracking. Most oil coolers that are attached to the motor are extremely Robust.   Nev

[IBob]

Hi Marty, the Sav has a bracket from the gearbox side bolts to shock mounts to the oil cooler top. This is a fabricated bracket that picks up the side bolts and has a crossmember across the top of the cooler.

 

The bottom of the oil cooler is shock mounted to a bracket made in the same way that goes back to side bolts under the engine.

 

That point also serves as the mounting point for the top of the coolant radiator, which is also shock mounted. The rear of that radiator is pulled up to the underside of the engine by a tie.

I'm sorry I don't have a clearer pic.

Edited June 14, 2023 by IBob

[IBob]

Partial glimpses here taken during build, when I was trying to figure out why my exhaust pipe wanted to occupy the same space as the cylinder coolant plumbing..............:

 

[Marty_d]

Thanks Bob, that's very similar to what I've done so far... so in the photos ignore the fact that the oil cooler isn't actually there, the bracket holds it.  

Top of the OC brackets have vibro-stops, then at the bottom/back there's vibro-stops going to the radiator, and also on the bottom of the radiator - and the longerons going from the top to bottom of the radiator are bolted to the bottom engine threaded holes.  

I still have to adjust this, maybe get it closer to the muffler, as the cowling makes contact with the starboard side of the radiator right now.

[facthunter]

If ever you run the engine with a variable strobe light and camera you will be shocked at the amount of vibration going on. Under a lot of carburettors there's a drain tray and they invariably crack. Moreso on four cylinder motors. Al fatigues easily. Nev

[IBob]

You do really nice work, Marty.
My radiator bottom corner initially touched the cowl on the port side, I was able easily to pull it up at the rear to give good clearance.

[Marty_d]

I bought some oil cooler fittings from a local performance auto store (ended up going with Aeroflow fittings) and thanks to research done by @skippydiesel I went with Gates 8GTH half inch hose, stocked by the local Hardy Spicer ($67 inc GST for 2m, if anyone's looking at prices).  The Aeroflow fittings weren't cheap but the 135 and 45 degree angles on them means a better run for the oil lines.

Photos show temporary fitting - still waiting on some ally M22x1.5 nuts I've ordered, I'm in no rush so ordered from China.   Will still probably have to cut them down to fit them under the oil cooler mounting.  Hoses can disconnect quite easily.

Unfortunately I'm going to have to take the knife to the cowl (again - it's going to have more blisters than a teenager with acne) - the starboard side of the radiator is pressed hard against it and there's no wriggle room.  Hoping to do that tomorrow.  I have a spare carbon fibre blister as I made 2 when I only needed 1 for the throttle clearance.

 

 

[rgmwa]

Probably not that useful but this plans link shows the oil cooler and radiator installation on the RV-12iS.

https://www.vansaircraft.com/wp-content/uploads/2021/04/50iS-U_12iS.pdf

 

[Marty_d]

Thanks Rob, that's very handy.  I wondered what that nipple on the oil tank is, now I know - overflow!

[rgmwa]

Glad it was useful Marty. Van’s documentation is really good.

[IBob]

Nice work, Marty.
FWIW both my port lower coolant hoses pass through the angle of the lower engine mount, rather than under it.
As I recall, I adjusted (rotated) the position of the fittings on the coolant pump to direct the hoses through that gap. It is easily done with the housing out using moderate heat.
I mention that only as it may give you a bit more clearance under there.
(PS: but whatever you do, don't mess with the fittings in the cylinder heads. They use a high temp Loctite and if you get seepage there it is a b*****d to fix!)

 

 

[Marty_d]

Cowl fitted again with a hole for the radiator end. Bit of a bugger as the blister I have is too big so I'll be doing more fibreglassing.

 

[facthunter]

You have to admit those engine installations are a plumbers nightmare. Nev