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It was used in the "Nasty" class torpedo boats too, but diesels have bit different power output than gas engines. At least until recently. The march of technology
Until the books you recommended arrive you guys and wiki are my primary sources. So for engines that are going to get shot at is the expense and complexity of sleeve valves a bad idea? The few books I have that give small mention of them do not give the impression they were superior.
Yes, indeed.I wonder what's next?
I saw the electric Lotus..the Tesla on a test and it went rather well to say the least.
Cheers
John
Perhaps this may be the best starting point by creating a hybrid liquid cooling system for this engine. Maybe that would have helped with the overheating problems of the B-36.
.....how are you going to feed these monsters you're proposing? Wouldn't the massive fuel loads result in rapidly diminishing returns on over-all aircraft performance.
All the power you propose may increase climb rate, acceleration, and load carrying, but do nothing to knock down the mach wall of propeller tip speed and airframe design. How are you going to overcome those issues?
Contra-rotating propellers? Did anyone ever really get those right on a piston engined aircraft? I'm not saying they couldn't be made to work, just look at a Tu-95, but are they really worth the complexity and vulnerability?
What is your opinion on a sleeve valved engine versus poppet valved engine in resistance to battle damage and ease of repair?
Its funny, because we can talk displacement and HP ratings, but actual performance of the plane seems to be where you end up putting the damn radiator.
under wing?
chin?
aft the pilot?
It would appear that aft the pilot offered the least drag to the air frame, but then its also more vulnerable to enemy fire.
Reason for keeping it on the chin may have been to keep all vulnerable parts in one area of the air frame.
Perhaps a part two of your question would be how to build a better cooling system?
Here is a British magazine article from 1941 describing the Hercules.
1941 | 2827 | Flight Archive
While there maybe some war time propaganda in there along with some politically incorrect view points, the flight archives are a wonderful resource and a good insight as to what some of the thinking of the day was.
Edit, if you have trouble try a different browser, for some reason it doesn't work with google chrome but it works fine with firefox
Yes and no.
It does depend on what service the engine will see. Bomber, fighter, reconnaissance, etc. A 3000lb, 3000hp engine is probably not the best for a fighter, where light weight is a virtue, but would be great in a B-29.
Propellor tip speed would be adressed in the propellor reduction gearing - turning the prop more slowly. Or replacing the prop with a smaller diameter alternative.
I don't think a contra prop is any more vulnerable than a single rotation prop, other than there are two mechanisms that can go wrong rather than one.
Contra props allow more power to be absorbed, and can be with smaller diameters than single rotation props. They also eliminate the torque effects - which cuases aircraft to turn and roll better in one direction than the other.
Macchi had some success with their go at contra-props, with the MC.72. Though, to be fair, that was essentially two separate engines. A similar thing could have been done with the V-3420, as they could be set up with opposite rotating crankshafts. The Sabre had both cranks rotating in the same direction, so it wouldn't have been as easy.
Rolls-Royce were probably the most successful at using contra-props - The Shackleton and late model Seafires had contra-props fitted to their Griffons.
I think there was a 3000hp engine powered B-29 but it was called the B-50
I was thinking of fighters with the 5000hp monsters proposed when I posted the fuel issue. With the much lower horsepower engines already in use piston engine fighters were being pushed about as fast as mach allows.
I knew about the late model Seafires and Spits, but forgot about the long serving Shackleton. I understood the advantages they promise with torque cancelation and smaller diameter props. But I suspect that with a contrarotating gear box a very minor hit in combat that would be sloughed-off by a single prop gear box would result in frequent XF-11 type events. I recall they were removed from some late mark Spits because of problems. I don't thing the Seafire or Shackleton ever had their day in battle to determine vulnerability of contrarotating props.
I have been within 6 inches of the Tesla. There was one parked at my Doctor's office a month ago. It is great looking and definitely displays the Lotus bloodline. If only it wasn't so expensive. I saw it reviewed on Top Gear awhile back. The real Top Gear, not that genetically deformed and mentally deficient American clone of Top Gear.
It would seem that the leading edge radiators were among the best for drag - Whirlwind, Mosquito, Tempest I.
This probably coincides with the XP-40 have a rear scoop originally, but then instead designing it into into the chin, due to the roll the aircraft.
The Mustang and the P-39/Aircobra both had aft pilot radiator intakes which both had the same Allison engines.
Their top speeds increased remarkably over the P-40 by that engineering move alone.
Well, of course not all of the increase in speed was due to the radiator placement, however the P-39, and early P-51As did use the exact same power plant as did the P-40. Part of having a better drag profile would be eliminating the chin radiator.Ah, I see, the fact that the P-39 and P-51 had different airfoils, different fuselage contours (the Spitfire lost 6mph by fitting the bullet proof glass to the outside of the wind screen) had nothing to do with the different drag, it was all radiator placement?
Once again, I ask for somebody to come up with proof that the P-40 was "supposed" to be a close support (ground attack) fighter.
Leading edge radiators were not the best for drag.
The intake usually disrupts the boundary layer going over the wing, which causes more drag than just the frontal area of the intake.
Similar to sticking your hand out of the window of a car, the air that doesn't fit in the intake creates a pressure gradient that increases the aerodynamic drag of the original frontal area. The drag is not just created by your hand, but also extends to the air trying to go around your hand.
This disruption can interfere with air going over the wing, which would simulate the same effect as having a thicker wing section.
The point of putting the radiator on the leading edge has its benefits despite the drag.
The Tempest was a heavy bird, and designing drag into the air frame may have been beneficial to help control over speeding.
Birds that flew low altitude missions that were more vulnerable to ground fire and flak would also be less vulnerable since their would be less ducting/plumbing for the radiator, and having it centered near or around the engine doesn't make it any more vulnerable.
This probably coincides with the XP-40 have a rear scoop originally, but then instead designing it into into the chin, due to the roll the aircraft.
The Mustang and the P-39/Aircobra both had aft pilot radiator intakes which both had the same Allison engines.
Their top speeds increased remarkably over the P-40 by that engineering move alone.
They probably had no quams about lend leasing the P-39 because of the learned hazards and limitations of the rear-engined plane, but the Mustang had too much potential to lend away, at least, not until newer and improved versions were made.
The P-51 was considered more vulnerable to ground fire which is no surprise given my explanation, but being primarily intended for long-range escort, why worry.
If you are using an annular radiator then it doesn't much matter if the engine is flat or V or inverted V. In fact either of the V's is going to be narrower than a flat engine for better pilot visibility. A Napair Sabre was about 10in wider than Merlin or Griffon. using bigger cylinders would have only made it wider. Sabre already had a piston speed of 3084fpm compared to a Merlin's 3000fpm. a larger cylinder is going to mean lower revs than the original Sabre.
The big problem with a lot of these engine was keeping them cool enough to stay running. At 15lb of boost an 4 stroke engine is moving about the same amount of fuel and air as an EQUAL sized 2 stroke per minute with no super charger. Supercharging a 2 stroke means that much more heat being generated in the cylinder every minute. There may be some advantages but I wouldn't expect a big jump in performance.
You also need a supercharger that could keep up with it
I was under impression that the engine layout (opposed vs. V) allows greater revs? I know that boxer is wider (was driving the Alfa 33 long time ago); placing it lower would've meant that it's in line with wings, hopefully (sketch attached). Ditto for twin-engined usual installation.