Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Cajunn on April 25, 2009, 03:19:25 PM
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I was asked a question by one of my squad mates and I didn't have an answer and told him I would ask. The question was "can you fight with the saddle tanks on the spitfire, and does it hurt the performance?" He was told that you could and that's why the saddle tanks were made the way they were, it had minimum drag and was meant to stay on while in a fight.
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They were't meant to be left on. Pilots sometimes forgot the 30 gallon tank was still on in the heat of battle, but it wasn't meant to be left on in a fight. They'd keep them on and bring them home if the flight was uneventful
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I hardly notice a difference with them on or off... So I suppose you could tell him it really doesn't matter! :P
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theres a report somewhere on spitfireperformance.com which says the 30gall didnt noticeably effect handling. I tested a spit VIII in AH and the difference is 2-4mph. I always leave em on - one less thing to worry about :)
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Definitely does not hurt performance as much as much as the "suet case thing", the 75 gallon tanks. But still sometimes every milligram can make a different. In a stall fight for example it would be a good idea to drop it, but in an everyday dogfight (especially when your wining) would not hurt to keep it on. I usual keep it on.
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Usually the 30gal is enough for me to get to the fight and settled in, and normally I remember to drop it. I don't see much of a difference with it, but I bet a few times it's saved my cartoon pilot's life.
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The performance deficit was not too much of a problem, especially for what superiority later Spitfires enjoyed.
RAAF pilots were known for bolting the 30 gal tank on the plane during 1945, but then again, they were staying out of heavy combat zones.
In the game, every little thing hurts performance just like in real life. If you want the most out of your bird, drop that tank when empty. Taking the Spitfire VIII can usually be a healthy alternative due to its slightly longer range than the IX. So if you're going anywhere where the IX will need extra gas, try just taking an VIII.
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I would also have liked to have the 170 gallon tank for the Spits.
(http://img88.imageshack.us/img88/8912/lastscantl1.jpg)
Also, I'm not sure if our Spit XIV has the 75 imp gal rear fuselage tank?
An interesting anecdote is the two American long-range Spit experiments. The Americans modified two Mk XIs, MK210 and MK317, at Wright field. Internal fuel capacity was increased by fitting a 43 gallon tank in the fuselage behind the pilot’s seat, and two leading edge tanks of 16½ gals each. Additional fuel was carried externally in two 62½ gallon P-51 type drop tanks suspended under the wings on P-51 bomb racks. Oil tank capacity was also increased to 20 gallons. The still air range of the modified Spitfires was approximately 1,600 miles. Both flew non-stop across the Atlantic from Newfoundland. MK210 tested by RAE at Boscombe Down.
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If it had been needed, the Spitfire could have been modified to be a long range escort fighter. Interestingly, aerobatics were not advised when the rear tank was full, just as in the P-51.
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I've seen a lot of instances of fwd CoGs being called problematic, but IMO, the real bugger is rear bias.. How could you have too much front bias, as far as dogfighting agility went?
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Moot from what I have read with the Spit 9, 11, and 16 pilots notes, confirms your thoughts about the aft CG.
(http://332nd.org/dogs/baumer/BBS%20Stuff/1.jpg)
(http://332nd.org/dogs/baumer/BBS%20Stuff/4.jpg)
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<--- Spit Dweeb.
I fight with mine on all of the time. If things get really hairy and I think about it I might drop it. On the other hand there have been times I carried it for my entire flight even after it's dry.
I don't really notice too much of a difference. If you're losing the fight it's probably not because of the drop tank.
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Thanks Baumer.. I can't recall any US planes that had reportedly too much weight forward.. I'll try and remember, maybe someone has documentation of one, and more details on why it would be a problem.
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I would also have liked to have the 170 gallon tank for the Spits.
Also, I'm not sure if our Spit XIV has the 75 imp gal rear fuselage tank?
An interesting anecdote is the two American long-range Spit experiments. The Americans modified two Mk XIs, MK210 and MK317, at Wright field. Internal fuel capacity was increased by fitting a 43 gallon tank in the fuselage behind the pilot’s seat, and two leading edge tanks of 16½ gals each. Additional fuel was carried externally in two 62½ gallon P-51 type drop tanks suspended under the wings on P-51 bomb racks. Oil tank capacity was also increased to 20 gallons. The still air range of the modified Spitfires was approximately 1,600 miles. Both flew non-stop across the Atlantic from Newfoundland. MK210 tested by RAE at Boscombe Down.
Planning on flying to Malta? Thats what the 170 gallon tank was designed for. Took the armament out, had to have a larger oil tank etc. It was a ferry tank. The 90 gallon tank was used late in the game, July or August 44 on when some of the Spits started to fly escort for RAF bombers having a shot at daylight stuff.
Understand I'm a huge Spit history guy, but for the game I sure don't see that adding those kind of tanks would serve much purpose. The fuselage tank on Spits was not often used either because of the CG issues.
As for the modified Spit IXs from the US. They were one off modifications but they were not viable for combat aircraft,
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I've seen a lot of instances of fwd CoGs being called problematic, but IMO, the real bugger is rear bias.. How could you have too much front bias, as far as dogfighting agility went?
I recall, back when I flew R/C airplanes, that moving the CG forward made the plane more sluggish and "gentle", while moving it back made it more unstable, and more prone to wigging out if it was too far back. Moving it back also generally made it capable of more extreme maneuvers, if it could be kept stable.
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The fuselage tank on Spits was not often used either because of the CG issues.
Doesn't seem to be modeled correctly in AH, then.
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Moving the CG foward relative to the center of lift increases longitudinal (pitch) stability. Stability can be static or dynamic but I'm only considering static here which can be described as the initial response after a control displacement. Controlability and manuverablility are related factors. When the CG is at the forward extreme the aircraft is positively stable; after a control displacement it tends to return to the previous condition. This can have a deleterious effect on manueverability as the aircraft can become too stable. To visualize the extreme case of positive static stability consider a bar dart, a very stable object but not very maneuverable. Some year models of the Cessna Cardinal actually had a slotted stabilator lifting down because folks were unable to flare at forward CG loadings and were pranging nosegears. Most aircraft are designed to be operated with some degree of positive static longitudinal stability. It makes them easier to fly as they tend to correct themselves after a displacement.
If the CG is approximately co-located with the CL the longitudinal static stability approaches neutral. The initial response after a control displacement is to remain in the displaced condition. This can enhance manueverability and in some cases can be advantageous. If you are flying an aerobatic routine you want the airplane to stay where you put it. Maneuverabily is enhanced because more of the wing lift can be used to turn the airplane due to the fact that it is not required to support the downforce on the tail (in addition to the aircraft weight) necessary to keep the nose up.
If the CG is behind the CL the longitudinal static stability starts to be come negative. The aircraft will continue to diverge from an initial control displacement. This is a manueverable condition and also will generally yield the highest top speed. There is no downforce on the tail so the wing can generate sufficient lift to remain airborne at a lower angle of attack (and therefore induced drag). The problem is that with a CG behind the CL recovery from stalls or spins becomes difficult or impossible. I once took a tiny boyscout for a ride in the front seat of a Schwiezer 233 and was too lazy to walk across the field to get the ballast block. We were nose high and climbing with full foward elevator at the takeoff but accelerated enough to regain elevator authority with a few moments. No huge drama but a good lesson in the effects of rearward CG.
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Doesn't seem to be modeled correctly in AH, then.
Cause the Spits in AH don't have it Krusty. not the DT, but a fuselage fuel tank that was fitted behind the cockpit that held 75 gallons. I don't know that I've ever seen it in a photo of a combat bird. I have seen photos of the installation, and ML417, a restored Spit IX has it installed.
I wouldn't want it added to an AH bird personally.
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Ahhh.. thought that was the term for the DT, my bad. Kinda looks like a saddle stand, only upside down.
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The slipper tanks on the Spit were really the first conformal fuel tanks, in particular the 30 gallon.
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Fuselage tanks, and you have the Spit21. A bird with contra rotating props, similar performance as a XIV (but not the torque) and long legs. Quad cannons?
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According to the pilots notes I have (see previous post in this thread) the Spit IX, XI, and XVI all could have the fuselage tank fitted for ferry purposes. It also sounds like it was a pain in the rear to fly with, "takeoff only from a long smooth concrete runway" or "except in an emergency, do not attempt to land with more than 30 gallons in the fuselage tank".
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Thanks Casca :)
I don't understand, though, why CG aft of CL would tend towards higher top speed.
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Thanks Casca :)
I don't understand, though, why CG aft of CL would tend towards higher top speed.
If the CG is forward of the CL the aircraft is nose heavy. You have to push down on the tail to hold the nose up. The wing does not know if it has to carry an increased load because there is a downforce on the tail or a fat chick in the cockpit. All it knows is that it has to operate at an increased angle of attack to support the airframe in straight and level flight for a given airspeed. The increased angle of attack causes an associated increase in drag; specifically induced drag or that component of drag associated with the production of lift.
At the aft CG loading the force on the tail is up, that is to say the tail is actually lifting with the result that the load the wing sees is decreased. The wing can operate in S&L at a reduced angle of attack and reduce the drag penalty. This is the reason that canard planform aircraft operate more efficiently, everything is lifting.
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Fuselage tanks, and you have the Spit21. A bird with contra rotating props, similar performance as a XIV (but not the torque) and long legs. Quad cannons?
Only a couple fitted with contra rotating props, not operational that way. Didn't have the fuselage tank either. The 4 cannons and the redesigned wing were the big dif over the XIV, but performance wasn't that much greater. 91 squadron had em before the war ended. No air to air in them though, patrolling over the hook of Holland mainly from England.
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I understand, thank you.
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Only a couple fitted with contra rotating props, not operational that way. Didn't have the fuselage tank either. The 4 cannons and the redesigned wing were the big dif over the XIV, but performance wasn't that much greater. 91 squadron had em before the war ended. No air to air in them though, patrolling over the hook of Holland mainly from England.
Oh, I thought they saw service like that. I knew about no air-to-air, but by that time the LW was hard to find.
I have an account from Neville Duke when he was testing one and the prop mechanism broke. I can type that one up for you if you do not have it Guppy :)
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Planning on flying to Malta?
I might!
;)
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Oh, I thought they saw service like that. I knew about no air-to-air, but by that time the LW was hard to find.
I have an account from Neville Duke when he was testing one and the prop mechanism broke. I can type that one up for you if you do not have it Guppy :)
Seems like I remember that one. One of the Spit XII drivers I got to know, later became a Supermarine Service Test Pilot after his combat tour. He did the production tests on the 21 and his most eventful flight was taking off in a Spit 21 with the Ailerons reversed. Tough to have to fly it the opposite of normal just to get it back on the ground :)
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Duke's problem was that the pitch of both parctically went flat. So he could barely make it to the airfield with full power. What a silly sight it must have been, an aircraft flaring in for a short 3-point landing with the engine on absolute full power :D
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Duke's problem was that the pitch of both parctically went flat. So he could barely make it to the airfield with full power. What a silly sight it must have been, an aircraft flaring in for a short 3-point landing with the engine on absolute full power :D
Another one of the Spit XII guys, Peter Cowell, was flying MB882 EB-B on a low level rhubarb and hit the water with his prop. Broke all 4 blades off equally so they were about half length. He got it back at full power too and barely moving :)
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Since we are telling prop strike stories.
Last year the Cdn Aviation Museum had a small fly-in. A speaker was this WW2 fighter pilot. He spent much of his time in the Sierra Leone area of Africa. A/c were delivered there, assembled and then flown across Africa to Egypt. He finally got to make one of these delivery flights. Khartoum was one of the staging bases. He and several others took off for Egypt. Shortly after take off a Polish Wing Commander radioed that his engine was vibrating but kept on going. When they had landed it was found that several inches of his prop tips was missing. He had a prop strike while taking off.
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My great uncle (Tony Jonsson) had a prop hitting a wave-top over the channel on a rhubarb mission. He made it (barely) to Manson on full power. The engine was by then quite tortured and the blades were all bent forward. Not broken though.
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Angus, did your great-uncle later fly a Mustang?
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Yes. Mustang III. Converted from Spit V to Spit IX, which to his disappointment was a short-term thing. They got Mustangs which he firstly looked upon as "American Junk", but soon was very pleased with.
BTW, the Mustang was unstable until you had burned up from the rear tank, or at least that's what he said. But basically an extremely pleasant aircraft, both fast and with a lot of gas.
Darn, I miss that guy ;)
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Thorsteinn Jonsson? I did a really amateur skin of his Mustang a while back. Wasn't a lot of info to go on, I think I skinned it as YT-J and was later told it was YT-B...
(http://img.photobucket.com/albums/v621/jocko417/th_YTJ2.jpg) (http://smg.photobucket.com/albums/v621/jocko417/?action=view¤t=YTJ2.jpg)
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Oiii!
I have not yet found the time and patience for skinning, but his Spit V carried the lettes Ju-J, and later it was YT-B, - I think. Both Euro-camo and later the desert camo, but that aircraft had the Vokes filter.
BTW, he is on some poster with the name of "company of aces" or something of the sort. Picture, signature, and aircraft picture, and on that one is his desert camo Spit V. Yeager is on that poster as well, and because of that (and other things) those two met and were able to compare their Mustang tactics.....
He did some hopping between planes I think, and his P51 went to scrap after he got shot up in the summer of 1944. Guess he got a new one.
P51C with a bubbly hood.
Did you read his autobiography?
Now, back to the Saddle tank, Tony flew his Spit V from Gibraltar to Algiers. The aircraft was assembled in Gibraltar and off he went. The squadron had an escort duty en route, so the cruise was not the one the pilots would have chosen, ending up with a couple of ditches due to fuel shortage. I can dig up the text on this if you like. One heck of a ride he had, barely making it to base.
I also have some data from Johnnie Johnsson about taking of for Malta with fully loaded Spit V's from an aircraft carrier at maximum distance. Slipper thanks there as well.
Promise: I'll type up if requested ;)
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Promise: I'll type up if requested ;)
consider this a formal request :D
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You bad!
I go digging in the stack. Luckily I did not include a DATE with my promise. This is a highly developed skill by now, since I happen to be married by a German. And she's a lawyer. And younger than me. A lot. :devil
But a promise is a promise, and I will absolutely give you some stuff. Happily, and rather soon.
:rock
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I happen to be married by a German. And she's a lawyer. And younger than me. A lot. :devil
marrying a lawyer, now that deserves a commendation for bravery :eek:
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Hehe, that may be true.
Anyway, I saw a mistake in a post a little bit back. I referred to a prop problem of Duke, it should have been Quill.
Back to Tony Jonsson. I have some pictures of the guy that are mine, but I do not have a space to host them. If any of you guys can do that, I can mail them to you.
And some tales will follow ;)
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marrying a lawyer, now that deserves a commendation for bravery :eek:
yea, divorce's always end bad for you :rofl