Pratt R-4360 Build

[Bryan1]

Hello,
Here is a link to my site showing progress on a Pratt R-4360 It's a slow project but I keep plugging away on it. Follow the link for up dates. http://www.nyemachine.com/pratt_whitney_r4360.php

 

[Bryan1]

Here is a photo of the distributor case. There are 7 distributors that fire from the front cylinder to the rear cylinder. No cylinder fires at the same time.

 

[John Rus]

Words are not enough, you should very proud of your work!

Keep up the incredible work,
John.

 

[Naiveambition]

Unbelievable craftsmanship Definitely worthy of a museum

 

[Bryan1]

This is the cam side of one of the case sections. The Pratt 4360 has 4 rows of 7 cylinders totaling 28 cylinders. Because each cylinder has a valve on opposite sides of the head, the engine requires 5 cams. The three center cams share duty opening valves for front and rear cylinders. You can see the alternating tappet holes in the first photo posted.

 

[petertha]

Wow, incredible effort. I also noticed a completed 18 cyl radial on your web site, is that a variation of the Hodgson?

Well if you have any more build pics, either from the past or going forward, I for one would keenly interested.

 

[Bryan1]

This photo is the oil pump adapter. the smaller hole at the out edge is for the starter pinion gear. I hope to make this engine remote starting. I'll try and "hide" the starter motor under the oil tank. The story about how I originally started this engine all began with a TV show. The show stated "The Pratt-Whitney R-4360, one of the seven most complicated mechanisms ever mass produced". I saw that as a challenge. My friends always ask me "What were the other six?" I don't even want to know, not until I get this engine running. So to get a handle on the whole radial engine concept, I purchased plans from Lee Hodgson and built an 18 cylinder radial. I deviated from the plans and enclosed the rocker arms and found a problem there with oil getting trapped in the lower push rod tubes and rocker boxes. So for the 4360 I designed an oil pump with two scavenge pumps and one pressure pump. One scavenge for the crank case and the other for the rocker boxes.

 

[kvom]

Is the prop variable pitch too? Wow.

 

[Bryan1]

I purchased the prop and hub from SOLO PROPS. I waited forever for that assembly to be delivered. Almost 10 months. The prop hub is capable of changing the pitch with adjusting screws inside the hub. My long range plans are to adjust the pitch while running using adjustable oil pressure and an internal hydraulic cylinder similar to the operation of an actual hub. That is why I made the hub is a little larger and longer than the original.

 

[Bentwings]

Nice stuff you are a real glutton for punishment.with a real constant speed prop. I’ll be looking for details on this. When it comes to props I have a huge respect for the potential dangers. Over the years I had props split and throw blades. I definitely won’t fight them.....lots of room. I’ve had my share of cuts and bruises from less than perfect props.I give any prop a wide danger path. When just a 22” in wood prop sticks in the wall like a KBar knife you quickly see the danger. Imagin a carbon fiber one! Yikes.
in my reading over the last several weeks there were accounts of prop problems that often led to ripping the big 4360 right out of the aircraft. In some cases resulting in a crashed plane. I haven’t enen started looking up how these props worked.
ok here is one I just ran into. Nice ISO drawing of a link rod. It shows
there is a pocket milled all around the inside perimeter. Not sure how deep but I’d guess about a 1/16” deep with a tiny radius all around the bottom. Ok you can buy an end I’ll to do this. Now the hard part. How to cut the radius around the top side? Yeah you can get an end mill for this. A corner rounder won’t work around the pin ends. So short of free handing this on a buffer, machining this is going to take some creativity Because it will leave an edge around the pin ends. Maybe designing something to accommodate this would be easier. I’ll have to create a cad model first. Cnc might do it with a number of nearly blank passes but buffing will still be required.
my son is a cnc nut. Every thing can be done on these cool machines According to him. Unfortunately he has 0 experience in the shop making chips.
im going to go fire up my cad work station. It’s been almost 20 years since I retired so I may have some relearning to do.