He-162 Salamander

[The Basket]

If you look at the Folland Gnat, you will see similar issues to the 162.

The Gnat was small, agile and fast. Cheap as chips.

It also had no range and couldn't carry a worthy bombload. Even if it did it didn't have the range to carry it. The Raf pilots loved it but it was of limited use. Point defence dogfights only. Gnats didn't fall apart either.

However...in a Battle of Britain situation then Gnats would have flown off the production line.

The qualities and weanknesses of an aircraft are secondary to what mess you're in at that moment in time. Again had the Raf had 162s in 1940 then yeah they would have flown 'em. But never when they could be selective.

Desperation can do odd things to a man and beggers can't be choosers.

[kool kitty89]

I was just saying wing area isn't the only factor for turning performance, the wing efficiency, airfoil, lift to drag ratio, power/thrust-loading all affect this. Lift loading is the bigest factor with wing efficiency, area, airfoil type and thickness all efecting this. The laminar flow wing has low drag but also low lift so it will produce less lift than a comparable non laminar flow wing. Other low-lift low-drag wings (seen in the P-47, and as mentioned by Delcyros, in the He 162) were similar but not as poor at lifting as a true lamiar-flow airfoil. (though also not as aerodynamicly clean)

I'd like to ask about your thoughts on the He 280's potential, but that might get us too far off topic.

[Soren]

and the laminar airfoil woul more likely separate later than a non laminar flow wing - assuming clean surfaces.

That is very wrong.

The sharper leading edge and middle positioned max chamber of laminar flow airfoils means boundary layer seperation occurs at lower AoA's, the transition point moving forward more rapidly, and this is no matter how clean the surface is.

The low lift, low critical AoA and sharp & sudden stall is an inherent characteristic of laminar flow airfoils and is the very reason why modern fighters feature LE flaps or slats, thus eliminating the big disadvantages of the laminar flow type airfoil.

[Soren]

Originally Posted by delcyros

With 196 Kg/m^2 for landing (almost empty) and it´s low drag, low lift airfoil, the He-162 will not outturn many piston prop A/C low & slow.

Low lift airfoil ? Where did you get that from?

[Soren]

Also remember that the P-51's laminar-flow (low drag at the expence of low lift) airfoil had even lower lift per area than the 162's which wasn't a laminar flow airfoil.

Very correct Koolkitty.

However piston engined a/c benefit from their line of thrust running straight over the wings, increasing the lift over the wing at low airspeeds, and so when comparing jets with piston engined fighters it isn't as simple as just looking at the Clmax of the wing.

[Elvis]

I have a couple of questions.

With all this recent talk of manueverability of 162/262 vs. allied prop fighters, I was wondering if the same held true if the jet were to turn so the prop fighter had to turn against the rotation of its prop?

Also, (and maybe this needs its own thread), did the 262 have dual throttle controls?




Elvis

[Soren]

Yes, the Me-262 has individual throttle control.

[drgondog]

KK- here is an article that explains both what laminar flow is, and what the modified version ultimately installed on the Mustang achieved.

Laminar Flow Airfoil

The key to the understanding of both laminar boundary layers and subsequent flow, is what charcateristics enable a 'laminar flow' airfoil to delay positive pressure gradient to negative pressure gradient and cause a transition from laminar flow to turbulent flow... an instantaneous increase in drag over laminar flow.

The more you retard this change in pressure gradient and maintain a laminar boundary layer, the less drag you produce - all other factors being equal.

The Mustang had wind tunnel results of nearly 40% of chord but never achieved that in real practice... being closer to 28-30% with average factory finish.

Nevertheless, the Zero lift drag was less than every other conventional wing of similar thickness.

[drgondog]

BTW - I have seen several sets of figures for the He 162?

Are these right figure for the He 162A-2?

Wing span = 23.7 ft
Wing Area = 120 sq ft
Gross Weight - no external stores = 6,187#

[Soren]

He-162 A-2 specs

Wing area: 14.5 m^2 (156 ft^2.)
Wing span: 7.2 m (23.62 ft)
Weight fully loaded: 2,800 kg (6,173 lbs)

[Soren]

A very good site on the He-162: Heinkel He 162

[kool kitty89]

But prop wash wont delay tip stall much since most is concentrated at the centerline.

The He 162 didn't use a laminar flow airfoil, but maybe Delcyros meant it used another low-drag airfoil-- the P-47 had a low-drag airfoil iirc, though not laminar flow and had better stall characteristics than the P-51.


I'm not an expet on aerodynamics (though many are here, I know Soren and Delcyros are quite knowledgeable), but I have a decent grasp of the general concepts. From what I've read on this forum about lamiar airfoils is that they tend to bypass turbulent flow and go straight to separated flow (stalling) at high AoA with little warning.


That aside the He 162 has about the same wing loading (maximum loaded) as the P-51D (max fuel clean configuration) both just over 40 lbs/ft2. (much better than the Me 262, albeit it had the advantage of LE slats-- which could add another ~25% lift fully extended)

Now disregarding the type of airfoil, the He 162 would weigh quite a bit less by the time it engaged the enemy (lets assume 40-50% fuel expended). While the P-51 would likely still have all internal fuel (still carrying drop tanks). So if the P-51 drops tanks and engages it will have a higher wing loading than the He 162 and poorer roll, climb, and acceleration (at least above 300 mph) as well. Plus the 30sec 115% over-rev boost (923 kp) of the 003E would allow better acceleration/energy retention in maneuvers-- along with the fact that at ~60% fuel weight is down to ~2,400 kg and thrust/weight is up to .33 normal and .38 with over-rev!

And at optimum combat cruise at altitude 1000 km range was possible at full 2,800 kg loaded weight, this cruise was still achieved at a speed comparable to the P-51D's max speed in WEP (with wing racks) with an endurance of ~85 min at 438 mph at ~30,000 ft.

Does this comparison seem accurate to you guys?

[kool kitty89]

These figures from Delcyros seem to match this except the wing area seems in conflict. (most I've seen state 14.5 m², and the wingloading Delcyros posted on this thread matches this) And the Max takeoff of ~2,700 kg from that link is considerably different than most sited at 2,800 kg usually stated. Though the empty weights and wing-span seem accurate...

From: http://www.ww2aircraft.net/forum/avi...-iii-2642.html (He-162 vs Meteor MK-III)

spanwidth: 7,2m
aspect ratio: 4,65
wing area:11,16 m²

Weight fullyloaden---fight endurance(100%)He-162 A2:
2634 Kg (5800 lbs) ---20 min at sea level
2889 Kg (6361 lbs) ---30 min at sea level
wingload: 240 Kg /lbs per m²

Defensive:
Armor: 70 Kg (154 lbs) in front of the cockpit
Ejection seat for the pilot
sustainable G-forces: 6.5g -serial planes
max G-forces: 8.5g -serial planes
max stick forces at 1000 Km/h (617 mp/h): 8,5 Kg / 18,7 lbs

Offensive:
gunsight:
Revi 16B or -16D:
most prototypes and all serial planes
EZ 42computing gunsight:
He-162 M30 and M31, later probably at JG-1

2 MK 108/30 mm with 50 rounds each (He-162 A1) or
2 MG 151/20mm with 120 rouns each (He-162 A2)

Poerplants----thrust output

BMW-003 A1/2----800 Kp (1761 lbs) _He162 M1-M10
BMW-003 E1----800 Kp (1761 lbs), 923 Kp (2032 lbs at 30 sec. overrew)
installed from He-162 M18 onwards into all serial planes
Jumo-004D4---932 Kp (2052 lbs) He-162 M11 and M12
He-S011A-----1300 Kp (2862 lbs) He-162 M14 and M15 (not completed)
As 014------2* 400-500 Kp He-162 M 42

(lifetime BMW-003A/E: 200+ hours, Jumo-004D: around 50 hours,
He-S011A: unknown, AS-014: unknown)

Service seiling: 11.700 m (around 38.500 ft)
Top speed at sea level: 790 Km/h at 100%
---------------------------820 Km/h at 115 % (30 sec.)
Top speed at 6000 m (nearly 20k ft): 840 Km/h at 100%
---------------------------880 Km/h at 115 % (30 sec.)
Top speed at 11.000 m (36.500 ft): 780 Km/h at 100%
---------------------------810 Km/h at 115% (30 sec.)
highest recorded speed: 905 Km/h at 6.800m (at 115%)
limiting Mach speed: 0.845
critical Mach speed: 0.867

flight endurance at 6.000m: 33 min (at 2634 Kg)
"---100%--------at 11.000m: 57 min (at 2634 Kg)
"-----"------------at 11.000m: 85 min (at 2889 Kg)
Range at sea level: 265 Km (at 2634 Kg)
-------"--------------: 390 Km (at 2889 Kg)Range at 11.000m: 660 Km (at 2634 Kg)
--------"------------:1000 Km (at 2889 Kg)
take off distance: 800 m
take off distance with jettisonable rocket assistance: 380 m

[Soren]

The wing area is 14.5 m^2, and performance was as follows:

Lenght: 9.05m
Wing span: 7.2m
Wing area: 14.5 m^2

Weight empty: 1660kg (3,666lbs)
Weight fully loaded: 2800 kg (5,942lb)

Top speeds:
890 km/h at SL
905 km/h at 5,950 m

Climb rate: 23.4 m/s (4,609 ft/min)

Service ceiling: 12,040 m (39,800 ft)

Range: 975 km (606 miles)

[drgondog]

Originally Posted by kool kitty89

But prop wash wont delay tip stall much since most is concentrated at the centerline.

What airplanes were you thinking of where 'prop' wash influenced tip stalls?

The reason for 'wash out' or reducing the angle of attack at tip is because the lifting line results in a tip vortex that effectively increases freestream angle of attack at the tip - when compared to local angle, say at 50-60% of the span. So with higher effective AoA at tip, unless you do something to reduce the tip AoA from the rest of the wing it will stall first - assuming same airfoil type and characteristics..

The He 162 didn't use a laminar flow airfoil, but maybe Delcyros meant it used another low-drag airfoil-- the P-47 had a low-drag airfoil iirc, though not laminar flow and had better stall characteristics than the P-51.

The 51 didn't use a pure Laminar flow airfoil either - it was a proprietary NAA airfoil derived from a laminar flow 15 % thickness at 40% chord line. So what would you point to for your conclusions that it had better stall characteristics. Flight test quotes would be a good source if you have a way to point me there?


I'm not an expet on aerodynamics (though many are here, I know Soren and Delcyros are quite knowledgeable), but I have a decent grasp of the general concepts. From what I've read on this forum about lamiar airfoils is that they tend to bypass turbulent flow and go straight to separated flow (stalling) at high AoA with little warning.

Actually in the context of expert aerodynamicists - I'm not sure I've seen any experts on this forum yet, specifically including myself..how do you define 'expert'?

However, if you are trying to extrapolate the behavior of a P-51 wing in a very high turn in a flight profile nearing local stall, you will get warning in the form of 'shudder' and you better pay attention.. if, on the other hand the stall is due to level flight at a low speed, it is a gentle stall with no violent characteristics. The one case I am aware of where hte 'gentle warning' doesn't occur is the dreader aft cg problem of a full fuse tank - and that is really a stability issue - when it tries to swap ends.

Last, turbulent flow IS separated flow - both distinguished by immediate growth in boundary layer thickness and transition from positive pressure differential to negative. They are basically one and the same in the context of low viscosity flow over an airfoil.

What you might be trying to say is that different airfoils transition at different speeds and angles of attack.. I have no comment on comparing the He 162 to a 51 or any other airplane as I don't have the data.



That aside the He 162 has about the same wing loading (maximum loaded) as the P-51D (max fuel clean configuration) both just over 40 lbs/ft2. (much better than the Me 262, albeit it had the advantage of LE slats-- which could add another ~25% lift fully extended)

On the other hand the encounter you mention might have a 51 leaving Berlin area on the way to a base in Belgium and he is down to 100 gallons versus the He 162 climbing for altitude with full tanks? - in which case we have a wing loading in reverse scenario comparison..

Now disregarding the type of airfoil, the He 162 would weigh quite a bit less by the time it engaged the enemy (lets assume 40-50% fuel expended). While the P-51 would likely still have all internal fuel (still carrying drop tanks). So if the P-51 drops tanks and engages it will have a higher wing loading than the He 162 and poorer roll, climb, and acceleration (at least above 300 mph) as well. Plus the 30sec 115% over-rev boost (920 kp) of the 003E would allow better acceleration/energy retention in maneuvers-- along with the fact that at ~60% fuel weight is down to ~2,400 kg and thrust/weight is up to .33 normal and .38 with over-rev!

Some of which might help if his airspeed is below 350mph - but in any case the He 162 will out roll it. Having said that, the commentary on the He 162 was to be VERY gentle on the controls. Rolling puts big asymetric loads on aft fuselage due to rudders - and the common theme is 'be careful' with that manuever at low to medium speeds until the speed are high enough that much less rudder input is required through the manuever.

And at optimum combat cruise at altitude 1000 km range was possible at full 2,800 kg loaded weight, this cruise was still achieved at a speed comparable to the P-51D's max speed in WEP (with wing racks) with an endurance of ~85 min at 438 mph at ~30,000 ft.

I keep seeing 30 minutes duration for normal He 162 ops (whatever that means). Does anyone have figures on Specific Fuel consumption at different speeds and altitudes? That would help figure out how much fuel is used to climb to say 30,000 feet, cruise, fight for 10 minutes, return and have some reserve left. Other than that 1000km range has no context. A P-51D with full intyernal fuel, full ammo, 30 minute reserve at cruise - is about 510 mile radius... so you are telling me that the He 162 is good for 300+ miles radius under this type comparison?

Does this comparison seem accurate to you guys?

The He 162 was a superior airplane in the context of choosing to engage or leave a fight, just like the Me 262... There isn't enough history to evaluate it or derive assumptions about just 'how superior' it was.

Its excellent speed and small size was a major plus. It's low speed manueverablity/limits seem to be a minus, it's visibility aft is terrible, it's ability to loiter is not good - so the mission seems to be focused well on climbing, attacking and running - to get out of sight so that it can land safely.

As to what the wing loading is I'm having trouble finding an unimpeachable source for the dimensions and weights. Joe Baugher's site that Soren pointed out had a higher wing area and lower gross weight than others that I have found so far.

If someone has any dimensions on the wing (like root chord or mean aero chord) it would be simple as all the span dimensions seem to agree -