Radials

[lucky52]

Was there any advantage of the P&W 1820 twin row(B24)over the Wright 1830 single row engines (B17)? Both were in the 1200 hp range. All I know is just from reading about them and looking at the specs.From someone on the outside looking in,it seems the single row would be a simpler engine to make.Thankyou.

[bdk]

The DC-3 could be had with either one. Probably depended a lot on fleet commonality and engine availability.

[YAF340]

I think you have your planes wrong. The 1820 are the B17 engine. The 1830's where on the B24 and the PB4Y-2. We are building 4 of the 1830-94 to fit on our PB4Y-2 here at Yankee. We are looking for parts now. Our Plane has R 2600's on it now that Hawkins and Powers put on when it was a Fire Tanker.
Getting to your question, The single row engines have a much bigger Cylinder Bore. That is how you come up with 1820 ci (cubic inchs). The 1830 is only 10 ci bigger but has more cylinders. Hope this helps. JOE

Last edited by YAF340 on Fri Feb 05, 2016 6:25 pm, edited 1 time in total.

[exhaustgases]

Simpler to build yes, that is always the case with less parts in any mechanical device. But simpler doesn't always mean better.
Like the other poster mentioned something has to be bigger to extract the same power as the engine with more cylinders.
And the not so good thing about that is the loads that come with that, bigger loads and more stress are not a good thing especially in a recip aircraft engine.

[phil65]

Pratt's run smoother...

Pratt Inspector
Phil

[lucky52]

Thankyou everybody for your answers.I live 10 miles north of Hooks airport and get to hear the CAF B-17 quite a bit.Nothing sounds like those radials.

[Clifford Bossie]

Pratt's run smoother...

Pratt Inspector
Phil

The P&W R-1830 was one of the most produced big engines ever. Something like 183,000. A good, reliable engine.

Of course there is another superb Pratt, the R-2800, Greatest engine ever!

[phil65]

Thankyou everybody for your answers.I live 10 miles north of Hooks airport and get to hear the CAF B-17 quite a bit.Nothing sounds like those radials.

Those aren't Pratt's....

Phil

[Chuck Giese]

P&W 1830-90/92s are a heck of a lot easier to pull through than Wright 1820-97.

[Fearless Tower]

Was there any advantage of the P&W 1820 twin row(B24)over the Wright 1830 single row engines (B17)? Both were in the 1200 hp range. All I know is just from reading about them and looking at the specs.From someone on the outside looking in,it seems the single row would be a simpler engine to make.Thankyou.

The engines are actually P&W R-1830 and Wright R-1820. The number refers to the cubic inch displacement of the engine during a full rotation of the crank shaft. The similar horsepower is largely due to the similar displacement, but, as you mentioned, the Wright only uses a single row of cylinders vs the double row on the P&W. What does that mean...it means the Wright uses some big honkin' cylinders to achieve the same displacement (and likely has a lot to do with Chuck's comment about requiring more effort to pull the prop through).

As far as which is better....I've flown DC-3s with both. I didn't notice that much of a difference, although I didn't have to maintain the ones I got to fly. I have heard some folks say the Wrights are less reliable than the P&Ws. The Wrights may be cheaper to overhaul (because of fewer cylinders), but I believe the parts availability is better for the P&Ws.

[exhaustgases]

Was there any advantage of the P&W 1820 twin row(B24)over the Wright 1830 single row engines (B17)? Both were in the 1200 hp range. All I know is just from reading about them and looking at the specs.From someone on the outside looking in,it seems the single row would be a simpler engine to make.Thankyou.

The engines are actually P&W R-1830 and Wright R-1820. The number refers to the cubic inch displacement of the engine during a full rotation of the crank shaft. The similar horsepower is largely due to the similar displacement, but, as you mentioned, the Wright only uses a single row of cylinders vs the double row on the P&W. What does that mean...it means the Wright uses some big honkin' cylinders to achieve the same displacement (and likely has a lot to do with Chuck's comment about requiring more effort to pull the prop through).

As far as which is better....I've flown DC-3s with both. I didn't notice that much of a difference, although I didn't have to maintain the ones I got to fly. I have heard some folks say the Wrights are less reliable than the P&Ws. The Wrights may be cheaper to overhaul (because of fewer cylinders), but I believe the parts availability is better for the P&Ws.

No about displacement..... It is the swept volume of the pistons. And for all cylinders to draw in and burn the medium in the cylinders in a 4 stroke engine it requires 2 turns of the crankshaft. And depending on the speed (rpm) the valve timing and how good the exhaust system scavenges, and intake manifold pressure, there can be much greater air intake than the displacement.

[John Dupre]

One interesting thing to note is the Curtiss model 75 Hawk. In the P-36 it used the P&W R 1830 but in other versions for France it used the Wright R-1820. The Finnish Air Force ended up flying both version but preferred the Wright version since it was faster. With 6 fewer cylinders I imagine it was lighter but is that all that accounts for the speed differential? The Finns ended up converting all of their Hawks since they needed the Wright engines for their Brewster F-2A's which were even faster than the Curtiss.

[Rajay]

One interesting thing to note is the Curtiss model 75 Hawk. In the P-36 it used the P&W R 1830 but in other versions for France it used the Wright R-1820. The Finnish Air Force ended up flying both version but preferred the Wright version since it was faster. With 6 fewer cylinders I imagine it was lighter but is that all that accounts for the speed differential? The Finns ended up converting all of their Hawks since they needed the Wright engines for their Brewster F2A's which were even faster than the Curtiss.

Ditto the Grumman F4F (Pratt R-1830) versus Eastern/General Motors FM-2 (Wright R-1820) but don't know if there was any performance differential.

[TheBoy]

Pratt > Wright

(except when it comes to sound!)
Just my $0.02

[Larry Kraus]

When I flew for Express Airways, we had a C-47 with R1830-75 engines. The first time that I started one of the engines I shut it right down because I was sure that it had a broken connecting rod. I was assured by our Chief Pilot/ Director of Maintenance that the sound was normal and was just the crankshaft counterweights clattering. He turned out to be correct, and the sound died down after the engine warmed up, but I never did feel comfortable with all of that clattering racket on start up. We also had a C-53 with R1830-92 engines that was nice and quiet when starting. Go figure.