This post will serve as a placeholder for the system he used if I can recover it.
In the midst of a 5,000 file data dump from the internet archive, I found version 1.0 of Stu's system for fighters:
Stuart wrote:The Deadliest (Air) Warrior
In the spirit of the TV show, this thread lists combat aircraft for given eras according to a model assessment of their capability. This model works on accessible data that is common and consistent and avoids subjective impressions or ratings based on an opinion.
The model started life as revision 1.0 that featured the following rating data:
Speed - One point for every 10 mph over 200 mph
Range - one point for every 50 miles range on internal fuel plus any fuel carried in jettisonable drop tanks.
Firepower - one point for each pound of shot/shell/bullets delivered in a burst of standard length
Engine power one point for each 100 hp
Altitude one point for every 3000 ft altitude
Maneuverability points calculated by dividing 200 by the wing loading
Protection/strength Aircraft unloaded weight reduced to a standard 30 x30 foot size (effectively unloaded weight * 900 /wingspan / fuselage length) then one point for every 1,000 pounds. To that is added 2 pts for a bullet proof screen, 3 pts for an armored pilot's seat and 5 points for self-sealing fuel tanks.
It was subsequently replaced by revision 2.0 that replaced the raw engine power rating with a power-to-weight based factor.
Revision 3.0 included a penalty for aircraft that had significantly poorer roll rates than teh average due either to long wings or increased moment of inertia. Data tables are revised to comply with the latest revision although this may take a few days to implement.
Stuart wrote:What I have found is a formula for converting thrust into horsepower. Basically, its aircraft speed in ft/sec * thrust in pounds/550. I'm playing with that; if it works we can use it to include the jets (Just playing and stretching the excel sheet; an F-104G comes out at 863).
Stuart wrote:I've finally, blizzards and other things no longer in the way, sat down and looked at bombers. The following are the model criteria where they differ from the fighter model.
Cruising speed is used rather than maximum; this is because the bombers were in formation cruising to their targets.
Bombload is measured in multiples of 500 pounds; this puts the resulting figure in teh same area as other categories.
Firepower is divided by six to allow for gun power directed forward, aft, left, right, up and down. The actual weight of fire is important; there was a lot mroe to bomber defensive fire than just deterrence.
Agility is deleted. Bombers essentially didn't maneuver.
The inertia of the aircraft is now treated as a postive factor; that's because inertia = stability and that meant bombing was mroe accurate (what killed the Northrop B-35/B-49 more than any other factor was their bomb run instability).
Stuart wrote:KDahm wrote:
The bomber formula MK 1
The criteria
Speed: 1 point per mph over 200 mph using cruise speed
Range: 1 point per 100 miles on internal fuel (no Tokyo tanks)
Bombage: 1 point per 250 pounds of bombs, using the standard listed bombload
Power to weight ratio enginer power: engine power in hp multiplied by 100 and divided by max takeoff weight
Altitude: 1 point per 3000 ft maximum altitude
Strength or efficiency: MTOW minus empty weight reduced to a standard 60x60 foot size ((difference * 3600) / (wingspan * length), then 1 point per 1000 pounds payload
Defensive guns: 1 point per defensive gun, regardless of calibre (since they are mainly for deterrence anyway)
Engine penalty: Minus 5 points per engine over 2 (reflects the greater vulnerability, maintenance, and economic cost of 4 engines compared to 2)
Points of debate.
I'm not sure the engine penalty is valid. lot of four-engined birds got back on three or two engines; a high proportion of twin engined aircraft went in after losing one engine and they all did after losing two. Economic cost isn't a concern here (otherwise we'd be ina world of hurt with production hour differences) and its an open question whether four reliable but lower-powered engines are a greater maintenance burden than two high-powered but unreliable ones. The Manchester/Lancaster issue is applicable here. Also, the He-177/277.
I think the strength and efficiency issues need to be seperated. We already have a structural strength rating and we can adopt that pretty much as is (normalizing to 30 foot span/length. - the actual size of the normalized airframe doesn't matter so we should keep the existing figures where possible). Airframe strength is a critical factor; it measures the aircraft's ability to get back after taking damage.
I think the efficiency data is important enough in its own right to have a rating. (MTOW/unloaded weight)*10 might do the trick there.
It's arguable whether guns were just for deterrence. There is a critcial point here (one that killed the Luftwaffe). Fighter combat is Darwinian - the best survive and get to be very, very good and basically don;t die. Fighting bombers is random; it doesn't matter how good you are, getting caught be defensive fire is essentially a matter of chance. So, the bomber defensive guns slowly kill off the expert pilots.
Stuart wrote:KDahm wrote:
When you post the exact formula you use, please highlight the changes from my proposed model in the Fighters thread.
The changes are:
Allowing for differences in gun types used for defense. This was a major factor in the Pacific where the combination of heavy guns on the bombers and the light structure of Japanese fighters mean the losses inflicted by the bombers were significant
I reduced the bombload rating from one point every 250 pounds to one point every 500 pounds to bring things to the 1 to 20 point.
I eliminated efficiency which really duplicated data already in the system
Added in the stability factor which includes both the roll "penalty" now "lack of roll bonus" and an allowance for pitch instability. That's about it I think. Otherwise pretty much your model.
edit - oh yes, eliminated the penalty for extra engines.
Stuart wrote:Calder wrote:
The generalist approach to fighters made perfect sense to me because any one factor that was missing could be exploited by your opponent but for Bombers it seems to me that with WWII tech the no bomber can be made good enough to always get through and thus damage per sortie should be the most important characteristic.
Basically, there are three factors here. Getting through to drop the bombs. Hitting the target and thirdly destroying the target. Getting through is a combination of cruising speed, altitude,defensive firepower and armor. Hitting the target (assuming everybody's bombsights were about equal which is near enough to true) is a question of the aircraft's stability during its bomb run (St Curtis proved that) and destroying the target means carrying a large bombload.
Now, each of those three is critical. There's no point in carrying a huge bombload if the aircraft can't get through to a defended target with it (the RAF bombers come dangerously close to that paradigm). Likewise there's no point in carrying a huge bombload to a target if the aircraft doing the drop is so unstable the bombs get scattered over a vast area of countryside (the early USAAC raids came very close to that paradigm with the bombers taking wild evasive action susbtituting for lack of stability). Finally, there's no point in getting to the target and dropping accurately if the aircraft is only carrying a single small bomb. (The Germans came close to that paradigm). So, to rank as a high-class bomber, the aircraft has to do all three of those things reasonably well. They have to get to the target, drop accurately enough to be meaningful and drop enough to make the enemy's eyes water. Really the aircraft are divided up into those that did all three well (the B-29), those that diid two of them well and those that did one well. I tried this with a one point for 250 pounds and the result was that the bombload was essentially all that mattered. One might as well discard the rest. That negated two of the three basic requirements. The other problem is that there are some aircraft around that carried such heavy bombloads that the figures get to be absurd - Silverplate/Saddletree for example. But even excluding them, the four points per thousand is just too high.
Stuart wrote:Back to fighters for a moment.
A suggested minor modification based on reading that showed wing guns were often removed or not installed due to the effect they had on roll rate. Crunching the numbers suggests that each wing gun was equivalent to 1/10 of an engine. So, by increasing the roll rate penalty by 1/10 of an engine for each gun installed in a wing should compensate for this effect. This is a relatively minor change and if implemented would constitute version 3.1.
NewGolconda wrote:On engine penalty. If we are agreed that the rankings are independent of resources used at this point.
Twins are half as reliable as singles if they cannot maintain a positive rate of climb on one engine. That’s why tri motors were so common in the 1920's. From the early 1930's twins could offer a slight positive rate of climb - but a degree of caution is needed in that for much of the 1930's a twin at a full operating weight may only have the slimmest of climb rates (say 150ft/min) with full power and when brand new.
A worn 2 year service type with dinged and roughed up surface and engines slightly short of their nominal full power may be in service conditions a 0ft/min climb or -50ft/min climb. Do you want any ice on that?
Note that in these conditions, asymmetric power, more than the usual control forces being applied, pilot stress etc - a positive rate of climb does more than indicate an ability to stay in the air - it’s also indicative of the ease of replacing energy in turns etc. A skilled pilot may be able to compensate for asymmetric thrust, sacrifice height for speed to provide a margin to turn without stalling, avoid obstacles and weather and land again safe and sound. An average pilot?
I have some flight test for the Beaufort with 1200hp twin wasps – and it was exactly in that situation - 150-250ft min new, 0 to -50ft/min in service condition. I suspect these stops being a problem with higher power/performance types – B-25, Mosquito etc.
Four engines? A stable, safe configuration favoured for long range flight for many years. I am not sure why this would be penalised on anything other than resource use grounds.
KDahm wrote:DocMartyn, Page 4: B-25H
.....
Protection/strength 15
So I cranked in the strength and efficiency numbers suggested by Stuart, and I'm getting some very low values for strength that likely minimize it's contribution to the overall total. For the B25, I have an empty weight of 21,120 lbs, wingspan of 67.5 ft, and length of 53 ft. That scores to 5.3 points, or less than half the contribution of the guns. If I use the 60'x60' standard instead of the 30'x30' standard, it increases to 21.3 points. Most of the medium bombers look like they're about 60-70' x 60'. The other bombers are similar.
I give you
The bomber formula MK 1.1
The criteria
Speed: 1 point per mph over 200 mph using cruise speed
Range: 1 point per 100 miles on internal fuel (no Tokyo tanks)
Bombage: 1 point per 250 pounds of bombs, using the standard listed bombload
Power to weight ratio engine power: engine power in hp multiplied by 100 and divided by max takeoff weight
Altitude: 1 point per 3000 ft maximum altitude
Strength: Empty weight reduced to a standard 60x60 foot size ((difference * 3600) / (wingspan * length), then 1 point per 1000 pounds
Efficiency: ((MTOW minus empty weight) / empty weight) * 10
Defensive guns: 1 point per defensive gun, regardless of calibre (since they are mainly for deterrence anyway)
A representative bomber, the B17G:
Speed: 2
Range: 20
Bombage: 24
Power to weight ratio engine power: 7.3
Altitude: 11.9
Strength: 16.9
Efficiency: 8.1
Defensive guns: 13
for a total of 103.2 points
And a selection of WWII bombers are:
Boeing B29........................169.6
Boeing B17G......................103.2
Avro Lancaster....................102.6
Dornier DO217 M-1.............93.0
Heinkel HE-111...................89.9
Mitsubishi G4M...................88.9
Mitchell B25.......................88.7
Vickers Wellington...............74.6
And, unsurprisingly, the Deadliest Warrior is still.......................The Silverplate with an astonishing score of 168,089.0