Aircraft Engines Designed by the Duesenberg Brothers

[davparlr]

I have been an admirer of the engineering that went into the Deusenberg automobile engines and have wondered what could have been the results of Lycoming, or someone else, building a V-12 aircraft version of their Deusenberg designed six. Yes, I know they failed in there own attempts at high performance aircraft engines but I don't think Deusenberg was involved in this effort. Here are a few comparison with contemporary 1928-29 engines starting with the Duesenberg SSJ supercharged engine (as are the other engines listed).

Duesenberg SSJ car
Straight six
Displacement (CID) 420 cubic inches
Hp 400 @ 5000 rpm
Valve train dual OHC, four valves per cylinder
Power to displacement (P/D) .95

Mercedes Benz SSK car
Straight six
CID 433
Hp 295
Valve train Single OHC
P/D .68

Jumo 210 L10
Inverted V12
CID 1202
Hp 600
Valve train Single OHC three valves/cyl
P/D .5

DB 600
Inverted V12
CID 2070
Hp 1000
Valve train Single OHC four valves/cyl.
P/D .48

RR Kestrel
V12
CID 1295
Hp 686
Valve train OHC four valves/cyl.
P/D .52

RR Merlin
V12
CID 1650
Hp 950
Valve train Dual OHC four valves/cyl.
P/D .58

Allison
V12
CID 1710
Hp 1070
Valve train OHC four valves/cyl.
P/D .63

The Duesenberg brothers were undoubtedly two of the most gifted automobile and engine designers in the world at that time, having their cars set a world's speed record, winning at Le Mans and having several Indy 500 victories. In the late 20s and early thirties, very few, if any engines could approach their engine performance per cubic inch, not even the vaunted Mercedes Benz SSK. I've always wondered what would have been the results if they had turned their talents to aircraft engines starting with a V12 version of their straight six which could have had better power than the Kestrel and Jumo, and approaching the Merlin and DB at a much reduced size. Of course, they would probably want to increase the size to maybe 1200 CID.

 

[Shortround6]

It is not power / Displacement that interests aircraft engine designers but power / weight.

Car engines, even racing car engines, seldom have to put out their "rated" power for more than a few seconds or at most a minute and their "cruise" setting is often a fraction ( 1/4-1/2 0r less for powerful engines) of their peak power instead of 70% or better.

The Duesenberg brothers were very gifted, there is a story that Augie Duesenberg visited the Allison plant in the early years of Allisons design and looked at the plans. He thought the Crankshaft was too light. He was assured that the engineers had calculated the stress and everything was fine. later after testing, the crankshaft had to be beefed up.

But Aircraft engines are not car engines and trying to turn car engines into airplane engines seldom works well unless the car engine is way under stressed to begin with or de-rated so much that it shows little advantage over aircraft engines except, perhaps, cost.

 

[davparlr]

It is not power / Displacement that interests aircraft engine designers but power / weight.

Of course. Aluminum block would be required. I understand that the Duesenbergs used quite a bit of aluminum in their engine. My suggestion of building an aircraft engine by using an unmodified auto engine was simplistic.

Car engines, even racing car engines, seldom have to put out their "rated" power for more than a few seconds or at most a minute and their "cruise" setting is often a fraction ( 1/4-1/2 0r less for powerful engines) of their peak power instead of 70% or better.

I am not sure I completely agree with this. While you may be right about use of rated power output of race car engines being less than aircraft engines, I would not be surprised that race car engines are stressed as severely but at a different cycle rate. In a race like Le Mans, where hard acceleration cycles are required often over long periods of time, I suspect accumulative operations time at 100% plus power for the race car is higher than mission requirements of a typical fighter. In addition, this cycle rate of power had got to be extremely stressful on the engine. In fact, I suspect that designing an engine to cycle through low power to 100% under heavy loads over multiple cycles a minute for 24 hours and survive is more difficult than designing an engine to survive 100 hours at a constant 100% rated power. In any rate, I think the Duesenberg brothers were quite able to handle either. Since I have done neither, this is just a guess.

But Aircraft engines are not car engines and trying to turn car engines into airplane engines seldom works well unless the car engine is way under stressed to begin with or de-rated so much that it shows little advantage over aircraft engines except, perhaps, cost.

Yes, I was being simplistic in suggesting using the same engine as an aircraft engine. It would certainly need to be redesigned. I was really suggesting that what would happen if the Duesenbergs were given the task of designing an aircraft engine based on their auto engine which was very efficient for the day. However, I do think there have been quite a few adaptations of auto engines for marine usage, which is quite similar to the loading of aircraft engines and I am not sure they are derated much, if at all. Of course reliability is not so critical either.

 

[davebender]

Car engines, even racing car engines, seldom have to put out their "rated" power for more than a few seconds

I don't think you've watched many automobile races.

At a high speed track such as Daytona or newly repaved MIS (Michigan International Speedway) they run flat out for 400 to 600 miles, slowing down only for accidents and pit stops. During the 24 Hours of Daytona they run flat out for 24 hours.

 

[Shortround6]

I don't think you've watched many automobile races.

At a high speed track such as Daytona or newly repaved MIS (Michigan International Speedway) they run flat out for 400 to 600 miles, slowing down only for accidents and pit stops. During the 24 Hours of Daytona they run flat out for 24 hours.

Really, flat out for 400-600miles??? I am impressed. Of course I would be even more impressed if their average speed for a 400 mile race was close to their qualifying speeds. Or even if their 50 lap average was close to the qualifying speed.

I certainly take my hat off to those drivers that run the 24 hours of Daytona flat out for 24 hours. :

Map of track: Fileaytona International Speedway - Road Course.svg - Wikipedia, the free encyclopedia

What do they do for the corners??? keep engine at full throttle while using the brakes???

When set up for "endurance" racing like 24 hour or 12 hour races it was common practice to detune ( or drivers were instructed to use 200-500 less rpm) the engines slightly from the way they were set up for 2-4 hour races let alone sprint races or hill climbs. You can't win if you don't finish.

 

[davebender]

Impossible unless race cars are allowed fuel tanks large enough to last the entire race. That would be about 100 gallons for the Daytona 500.

 

[Balljoint]

IC engines don't scale up. A lesser displacement engine will turn higher RPMs and yield higher specific performance. The two-cycle model aero engines score very well.

That said, it's a shame the Dusenbergs weren't brought in to work on the Allison super/turbocharging issue.

 

[Shortround6]

Of course. Aluminum block would be required. I understand that the Duesenbergs used quite a bit of aluminum in their engine. My suggestion of building an aircraft engine by using an unmodified auto engine was simplistic.

I understand, I was trying to point out that there rather different considerations between car engines and aircraft engines and they often require rather different approaches. A good engineer may be able to work with both. I would note, however that the Duesenberg at 5000rpm had a piston speed had a piston speed of 3958 fps. A Merlin or Allison were at 3000fpm. A DB 605 at 2800rpm has a 2940fpm piston speed. A Duesenberg running at
3000fpm piston speed is turning about 3800rpm.

I am not sure I completely agree with this. While you may be right about use of rated power output of race car engines being less than aircraft engines, I would not be surprised that race car engines are stressed as severely but at a different cycle rate. In a race like Le Mans, where hard acceleration cycles are required often over long periods of time, I suspect accumulative operations time at 100% plus power for the race car is higher than mission requirements of a typical fighter. In addition, this cycle rate of power had got to be extremely stressful on the engine. In fact, I suspect that designing an engine to cycle through low power to 100% under heavy loads over multiple cycles a minute for 24 hours and survive is more difficult than designing an engine to survive 100 hours at a constant 100% rated power. In any rate, I think the Duesenberg brothers were quite able to handle either. Since I have done neither, this is just a guess.

The Le Mans engine only has to last 24 hours and many of them did not/do not last the race. 24 hours would be a pathetically short life for an aircraft engine. even 50-75 hours would be considered too short by most countries. Germans were 'spec'ing 110 hours for the DB 605A, I don't know if they got it. Allisons and Merlins were good for 200-300hours early in the war ( they got better as the war went on) unless they were eating dirt.

I once got into an argument on another forum about the Offenhauser engine in the 1930s vs aircraft engines. The Offenhauser (Miller) in the 30s was good for around 300-325hp from 255 cu in. but it weighed over 400lbs and while unsupercharged it was running on alcohol and using around a 14 to 1 compression ratio. (wiki data is for 1950s versions.)
in any particular 1930s Indy race (roughly 4 hours) around 20-25%of the cars dropped out with engine failures, including thrown rods. Qualifying speeds are somewhat different than race speeds too

Yes, I was being simplistic in suggesting using the same engine as an aircraft engine. It would certainly need to be redesigned. I was really suggesting that what would happen if the Duesenbergs were given the task of designing an aircraft engine based on their auto engine which was very efficient for the day. However, I do think there have been quite a few adaptations of auto engines for marine usage, which is quite similar to the loading of aircraft engines and I am not sure they are derated much, if at all. Of course reliability is not so critical either.

Mr. Duesenberg may have been able to pull it off, I don't know.

Miller tried selling several designs to the air corp. Only one got any traction at all and considering that it was the power plant in the Tucker XP-57 perhaps the less said the better? Offenhauser and Goossen tended to reign in Millers flights of fancy and turn them into usable engines bu they had parted company at this time.

As far as marine engines go, it depends on useage. Speed boat engines are note de-rated much at all. Cabin cruiser engines were derated somewhat ( 2000+ engines vers 1930-40-50 engines are in a different world as far as durability go) and engines for "commercial" use (working fishing boats and such) were considerably de-rated if used at all.

 

[Shortround6]

Impossible unless race cars are allowed fuel tanks large enough to last the entire race. That would be about 100 gallons for the Daytona 500.

Which is it.

Are they running flat out or are they running at less than full power to conserve fuel, it can't be both.

Pick a number of laps, 10 or 20 or 30, without a pit stop. If the average speed for that number of laps is not close to qualifying speed then they are not going flat out.

Now go one season on one engine. enough races to even hit 60 hours on one engine.

 

[johnbr]

Here are there aircraft engines.

 

[tyrodtom]

In my experience of circle track racing , i've often exceeded my qualifing lap times during a race.

When you qualify, you've got to hit your marks perfect, but the cutoff and on gas times you've chosen might not be fastest for current track conditions. During a race your times might be a little faster, because you gradually extend yourself a little further until you've reached the limits.
You don't really use less power, but you're at full throttle less per lap, if you're "cruising".

 

[model299]

I must say that first one up there looks rather cobbled together, almost like they threw the proverbial plate of spagetti at the wall to wee what would stick. Can you imagine having to sit behind that row of exhaust stacks if this were used in a single engined aircraft? Even if you're in an enclosed cockpit, those gases are gonna get ya after a while.

 

[WJPearce]

Jimmy Murphy driving a Duesenberg won the French Grand Prix at Le Mans in 1921. This was not the 24 hour endurance race that we think of today when we hear "Le Mans." This was a race of about 320 miles (520 km).

The Duesenberg brothers worked with Sandford Moss to develop their (sidewinder) supercharger in the early 1920s. Their involvement with aviation was from 1915-1919. In 1919 their exiting plant was sold to Willys and their company reorganized to focus purely on automobiles (no more marine or aviation engines). Since their attempts with aero engines were not successful, I do not think they had any interest in trying again.

The engines posted by johnbr are their Model H of 1918 (top pic) and their V-12 of 1916 (all other pics).

Engine: Model H
First Run: 1918
Type: 45° V-16, three valves per cylinder, water-cooled, aircraft engine
Horsepower: Direct 700 hp at 1,350 rpm, Geared 800 hp at 1,800 rpm
Displacement: 3,393 cu. in.
Bore: 6"
Stroke: 7.5"
Compression Ratio: 4.66:1
Gear Reduction: None or 0.758:1
Carburetor: Four 2.25" Miller updraft
Length: 88.75"
Width: 32"
Height: 38.875"
Weight: Direct 1,390 lb, Geared 1,575 lb


Engine: V-12
First Run: 1916
Type: 60° V-12, two valves per cylinder, water-cooled, aircraft engine
Horsepower: 300 hp at 1,400 rpm and 350 hp at 1,800 rpm
Displacement: 1,568 cu. in.
Bore: 4.875"
Stroke: 7"
Gear Reduction: None
Carburetor: One or two Miller or Schebler updraft
Length: 68"
Width: 31.25"
Height: 39.625"
Weight: 1,040 lb

They also built a couple of I-4s for aircraft use, aided Charles King's rework of the Bugatti U-16 (that became the King-Bugatti), and did some work on King's V-12.