Author Topic: How much better could modern tech make a world war two engine? (Read 1729 times)

FUNKED1 · « **Reply #30 on:** February 29, 2004, 05:56:13 PM »

Reno is only about 5,000 feet. Altitude for best airspeed for an optimal piston fighter is on the order of 20,000 feet. There were piston engine airplanes flying in 1945 which could touch 500 mph.

To look at what can be done with props, take a look at the Tu-95. 570 mph. That's a huge bomber with ~10,000 mile range.

TPIguy · « **Reply #31 on:** February 29, 2004, 06:44:33 PM »

I remeber this topic coming up a few years ago. I think the general consensus was that power would be no problem, but harnessing that power (prop design) would be the problem.

I think with modern engine designs and fuel managment, we could probibly build engines making the same power as WWII designs. But at 1/2 to 1/3 the displacement and weight.

With other improvements in aircraft design it would be possible to build a figher the size of a p51, with the payload and armamant of a p47 and the range of a b17.

A pure fighter could probibly have low alt La7 performance to 30k and be smaller, lighter and have far more ammunition and range.

Roscoroo · « **Reply #32 on:** February 29, 2004, 06:56:55 PM »

Quote

Originally posted by Captain Virgil Hilts
Nitro hemis in the Top Fuel and Fuel Coupes are 500 cubic inches and closer to 7000 horsepower. They use fuel systems that move 55 gallons of fuel per minute.

You couldn't load the Nitro powered eng correctly with a prop...
to many variables working in atmosphere .
Nitromethane works better the more load you put on it ... ( oh yea try 400-700 gals plus per min btw)

i'd be thinking in Titanium Rods , thermal coatings ,and perhaps hydraulic prop . hint hint

Captain Virgil Hilts · « **Reply #33 on:** February 29, 2004, 07:27:08 PM »

Quote

Originally posted by Roscoroo
You couldn't load the Nitro powered eng correctly with a prop...
to many variables working in atmosphere .
Nitromethane works better the more load you put on it ... ( oh yea try 400-700 gals plus per min btw)

i'd be thinking in Titanium Rods , thermal coatings ,and perhaps hydraulic prop . hint hint

I left out the words "at idle" regarding fuel consumption. It would be possible to load an engine enough to use nitro, you just couldn't use anything over about 30%.

firedome57 · « **Reply #34 on:** February 29, 2004, 07:41:41 PM »

Didnt the hydroplane racers use allison engines into the late 80's. Must have been the best power to weight until they started using tubine engines.

Roscoroo · « **Reply #35 on:** February 29, 2004, 07:54:41 PM »

True ..... I think i used to mix up to 42% outta dads barrel for my scale model 2 strokes ...

I would spend more time with the lighter alloys and improve the Hp to Weight ratio , and Aerodynamics

Vulcan · « **Reply #36 on:** February 29, 2004, 08:16:17 PM »

The Sabre VII in the Tempest was rated to 3000hp and in tests made 4000hp, and that was in '45

(3850rpm btw)

Captain Virgil Hilts · « **Reply #37 on:** February 29, 2004, 09:22:35 PM »

Quote

Originally posted by firedome57
Didnt the hydroplane racers use allison engines into the late 80's. Must have been the best power to weight until they started using tubine engines.

In the early seventies, or late sixties maybe, one of the hot Merlin builders was looking for a way to keep them from flying apart and discovered that the Allison rods would fit the Merlin. Before that, the Merlin was a loser at Reno.

The Merlin was more commonly available and was used in most Unlimited Hydroplanes, with a few Allisons in the mix for awhile.

As a matter of fact, the last piston engine win by an Unlimited was last year.

FUNKED1 · « **Reply #38 on:** February 29, 2004, 09:41:23 PM »

A lot of those boats are actually running Griffons.
Which, incidentally, were derived directly from the R engine, which at one point held the land, air, and water speed records simultaneously.

Captain Virgil Hilts · « **Reply #39 on:** February 29, 2004, 09:57:30 PM »

Quote

Originally posted by FUNKED1
A lot of those boats are actually running Griffons.
Which, incidentally, were derived directly from the R engine, which at one point held the land, air, and water speed records simultaneously.

True, they eventually went to Griffons, but they ran the Merlins and the Allisons for years. And for the most part what they ARE running is turbines.

firedome57 · « **Reply #40 on:** March 01, 2004, 12:30:14 AM »

The Allison(1989) actually won a race after the Merlin(1988), in unlimited hydroplane racing. I found this link when reading up on the subject. The Griffon won into the next century.

http://www.hydroprop.com/hydros/history/q037.htm

GtoRA2 · « **Reply #41 on:** March 01, 2004, 11:20:06 AM »

Guys
Who has the best prop designs of the war?

You look at the late war US props and they are all 4 bladed with big paddle blades.

The Germans still only used three blades but where even widder...

What was better?

GRUNHERZ · « **Reply #42 on:** March 01, 2004, 11:26:12 AM »

American props were prolly better. They had suared of tips which was better than the rounded tips of the german props.

As for three blades or four. Well the most efficient setup is a counterweighted single blade, the more blades you add the more they arodynamically interere with each other. However you need to transfer the power in some way so you need either more blades or bigger blades. For exaple rare bear has a three bladed prop made from big wide c130 prop blades.

The next model Bf109K the K14 fitted a new engine and a four blade prop - they made a tremendous performance increase prolly putting it into P51H performance category.

GtoRA2 · « **Reply #43 on:** March 01, 2004, 11:30:30 AM »

Hmm I did not know the K ran four blades.

What about like the -4 Corsair? it had four blades but rounded tips, and then ran the same prop from the -4 all the way to the -7, why did they not switch over to sqaure tips?

GRUNHERZ · « **Reply #44 on:** March 01, 2004, 11:36:41 AM »

Rounded is relative. I think pointed or eliptical is a better term, german props were elliptical while late us props tended to be more square/rectangular shaped. So the corsair had squared off blades.

K4 had 3 balded prop. This new K14 had a 4 blade - a few K14 may or may not have been built, nobody is sure.