Ikarus IK-3

[Knegel]

Hi,

I hope for Yougos it wasn't so. MS-405 never exceeded 450 km/h, and Hurry was a big peace of cake; it's performance was mostly due to it's 1030 hp Merlin rather to the very roomy airframe and thick wings.

With the same Hispano 880 hp power it's performance would have certainly been pityfull. So the IK-3 airframe was better than both of theese and should be compared to the very improved MS-410 (510 km/h).
Sorry, MS405 was a type, wanted to write MS406.
This are the datas i have for it:
Empty weight : 1.896 kg
Wing area : 17.10 m2
Full weigth : 2.426 kg
Max Speed - sea level : 401 km/h
Max speed - 5000 m Alt : 486 km/h
Initial climb speed : 13 m/s
Cruising speed : 320 km/h
Take-off speed : 140 km/h
Landing speed : 125 km/h
stall speed (No flaps) : 155 km/h
Max Altitude : 9850 M
Fuel capacity : 401 liters
Cruising speed fuel burn rate : 100 liters /hour
Full speed fuel burn rate : 200 liters / hour

I cant see why the IK-3 should have been faster. Maybe the prototype, without guns, but not the service plane, or they improoved the engine.

Why high alt? The low power request generated by high aspect ratio and a light wing loading plays a rule at any hight to outclimb or outfight in turning circles the same (what if) powered Me-109.

I don't think that IK-3 technology was more advanced that the Hurricane's, Bf-109's and MS-406 one's, but at least it was cleverly concieved (i mean optimised for it's low available power).

Like the french D-520, D-550, VG-33, soviet I-17, I-18, Czekh Avia B-135 and the rest of the unlucky underrated family...

Regards

VG-33

In lower altitudes planes in general fight at a higher IAS and so at a smaler relative Angle of attack. Due to this the advantage of a smaler induced drag is smaler than in high alt , where the AoA tend to be bigger.
High aspectratio wings in general produce a higher drag at high speed (IAS or mach), cause the airmasses cant get shifted away that good, this will happen more often in low level. Also a higher aspectratio is not got for the wing stability and roll ratio at higher speeds (IAS).

In higher altitude the power weight relation is in most cases very bad, so here its more important to have smooth controlls, a smooth stall edge and a effective wing for slow speed IAS. High aspectratio wings tend to have all this.

Thats why planes, constructed for high alt or for slow speed(IAS) in general have a higher wing aspect ratio(Mig3, Ta152H, P38H, Me109H, Spitfire with extended wingtips, most Bombers), while planes, made to fly at high speed IAS or mach or low altitude normaly get a smaler aspectratio(La(gg) 3-7, F4-U, He162, Spit cw, Me163, P39/400/63).

Alrounder normaly have a aspectratio of something around 6 (190, 109, P51, P40, Yak1 to 9, F6F, Typhoon, F2A, Zero, Ki-43)

High alt or slow speed planes normaly use > 6,3 up to 8,8

Low level or highspeed planes normaly use < 5,5.

There are only a few exceptions, where this thumb rule dont fit, like the P47, wich had a smal aspect ratio, but due to its engine it was still fast in high alt, still its climb performence was rather poor in relation to its power in high alt, most probably due to the wing. At the end he P47 got used in low level mainly. And the 262 had a rather high aspect ratio, but its swept wings probably did even this out.

Greetings,

Knegel

 

[VG-33]

Hello

Hi,

Sorry, MS405 was a type, wanted to write MS406.
This are the datas i have for it:
Empty weight : 1.896 kg
Wing area : 17.10 m2
Full weigth : 2.426 kg
Max Speed - sea level : 401 km/h
Max speed - 5000 m Alt : 486 km/h
Initial climb speed : 13 m/s
Cruising speed : 320 km/h
Take-off speed : 140 km/h
Landing speed : 125 km/h
stall speed (No flaps) : 155 km/h
Max Altitude : 9850 M
Fuel capacity : 401 liters
Cruising speed fuel burn rate : 100 liters /hour
Full speed fuel burn rate : 200 liters / hour



I cant see why the IK-3 should have been faster.

Mainly to exhaust blow-effect pipes, a much improved (less draggy) coolant system. Some better little aerodynamic details, without great importance on their own, witch taken altogether make the difference. I'm sorry to deceive you, in its form with retractable water cooler that wasn't used since last 20ies, the MS -406 was unable to maintain such speed (480 km/h) any longer, cause you soon need to turn the hand crack in order to extract the radiator more outside creating extra drag. So stabilised Morane speed wouldn't exceed 450 km/h, even less…

With the same 860-880hp Ycrs engine, the D-520 was able to reach 510 and + km/h, the MS 410 509-511, the Arsenal VG-33, 558 km/h. And the Laté 298, 310 km/h…

In lower altitudes planes in general fight at a higher IAS and so at a smaler relative Angle of attack.

In all altitude, even in the lowest one, planes do fight at AoA they need to: high for manoeuvring, turning and climbing, very high (Cl max) for landing, small for diving. I cannot understand your logic and TAS, IAS matters.

High aspectratio wings in general produce a higher drag at high speed (IAS or mach), cause

Here's something new...Well, the drag formula is F= Cd. S. V².

In general case S is the aera for wings, at 0 (ie Cdo) lift there aren't many differences between a 5, a 10 and more aspect ratio wing since they have the same aera and the same profile.

It changes when AoA increase:

So all things being equal, a high aspect ratio wing always have a growingly better lift coef Cl, and lower power requests with AoA increase.


Regards

 

[Knegel]

Hi,

the D-520 was smaler (wings) and had the Hispano-Suiza-12Y-45 with way more power than the Hispano-Suiza-12Y-31.

I never did read anywhere that the MS406 didnt reach 480km/h, while the MS410 should reach 510km/h??
I guess this is also mainly due to a better engine, not the aerodynamic. At this slow speeds IAS in 5000m, the aerodynamic is not as important as at sea level or with later planes, which did reach 200km/h more.

The advantage of smal aspectratio wings over high aspect ratio wings at high speed(smal AoA) is caused the problem to shift away airmasses. As smaler the aspect ratio, as easyer the airmasses can go around the wing.

Though, at the rather slow speeds in a horizontal flight of the early planes surly this is not the most important part, like the problems of creating a stable structure with a high aspect ratio wing and the resulting disadvantage in the rolling axe caused by the longer wings.
And this is mainly a problem in low alt, where the propeller/engine produce way more thrust than in high alt.

There is a reason why some jets got movable wings and why high alt planes in WWII got extended wings, while low/medium alt fighters had a smal aspectratio.

You wrote: "I cannot understand your logic and TAS, IAS matters."
As more thrust a plane have, as smaler will be the relative AoA he use, cause his speed will be higher.

In high alt(lets say 7000m), the Hispano engine had just around 50% of its max power and the thin air reduced the thrust even more. So at this altitude the plane for sure couldnt loop anymore and had trouble to make a barrel roll, without an big altitude drop.
Under such circumstanes the structural problems of an high aspect ratio wing dont matter much anymore, cause high g-forces are not expected, but the plane always need a rather high AoA, even to maintail altitude.

In low level, the engine/propeller produce most thrust and so the plane only need a very smal AoA to maintain altitude.
Here the planes get into high G force fightes, where the wings tend to bend and break appart and where this structural limits and the pilots ability to withstand high g-forces turn to be the limiting factor for the turn and roll.

So all over the in the middle used AoA will be way smaler than above critical altitude, in same degree the advantage of the high aspect ratio wing smelt down, while the disadvantages increase.

As result the FW190D9 is faster and more manouverable than the Ta152H in low alt. Same goes for the Spitfire with clipped wings.

Greetings,

Knegel

 

[VG-33]

Hi,

the D-520 was smaler (wings) and had the Hispano-Suiza-12Y-45 with way more power than the Hispano-Suiza-12Y-31.

It'why i have wrote

[I]With the same 860-880hp Ycrs engine, the D-520 was able to reach 510 and + km/h, the MS 410 509-511, the Arsenal VG-33, 558 km/h. And the Laté 298, 310 km/h…[/I]

In other way it's making no sense. We can compare also with an experimental MS-406 fitted with the same HS 12Y 45:
493 km/h at 5500m for the MS-406
534 km/h for the D-520.
We can also report, that D-520 aiframe evolved from the first trials with an HS Y-31 and the later with HS Y-45 ones.

I never did read anywhere that the MS406 didnt reach 480km/h, while the MS410 should reach 510km/h??

As previously, i have already asked to that question:

Mainly to exhaust blow-effect pipes, a much improved (less draggy) coolant system. Some better little aerodynamic details, without great importance on their own, witch taken altogether make the difference.

The MS 410, had a different wing and a tunneled radiator, and numerous other details to make it faster. (SN° 1028, 1040).
With hispano-suiza blowing pipes, instead of the bronzavia collector, the speed was improved from 44 to 41 km/h on SN° 1035, 1005 airframes. Some sources quoted that SN° 1035 had a fixed tunneled radiator during the trials, so the blow effect was only for 20-25 km/h increase, still not negligible indeed.*

I guess this is also mainly due to a better engine, not the aerodynamic. At this slow speeds IAS in 5000m, the aerodynamic is not as important as at sea level or with later planes, which did reach 200km/h more.

There might be some discrepancy between the serial engines, but no global increase in power from early to late Y-31 was never reported, at least some reliability improvements.

The advantage of smal aspectratio wings over high aspect ratio wings at high speed(smal AoA) is caused the problem to shift away airmasses. As smaler the aspect ratio, as easyer the airmasses can go around the wing.

Shift away? At sustainted flight the downwash is exactly the same for a 5 asect ratio or a 10 AR wing. For a 3000 kg airplanes, it makes exactly 3000 kg/s rate of flow in both cases. Except that at higher AoA the high AR wing does it better, at lower drag coast. At minimal Cd point (Cd0), no differences, at lower and negatives AoA the small AR had lower Cd values, but what's the use for that? Look on Cl/Cd polars.

Though, at the rather slow speeds in a horizontal etc etc....In low level, the engine/propeller produce most thrust and so the plane only need a very smal AoA to maintain altitude.

All that seems confused and badly assimilated in your reply. Take advantage of your banishement to read good mechanics of flight books...

As result the FW190D9 is faster and more manouverable than the Ta152H in low alt. Same goes for the Spitfire with clipped wings.

The Ta-152 had bigger wings, with higher AR; it was more manouvrable in turing circles (both due to higher lift and lower induced drag values) and climb than the D9 even at low alt; worse on roll, pure speed, diving. This with the same engine power, but with uncertainlies about the increase of weight due to the bigger (heavier) wing. I supposed no increase of Wing Loading value at least.


Just to say, the french company Azur had recently released a good-looking plastic kit 1/72th scale of the Rogozarski IK-3. Saw it two weeks ago, seems detailed and accurate, but i'm not the IK-3 specialist...

for instance
Maquette Azur FR013 Rogozarski IK-3 'Belgrade Defence'

Regards

* Mach 1, encyclopédie de l'aviation, n°88,89.

 

[Milos Sijacki]

Ikarus S-49 combined elements of both YAK fighters and Ik-3. For example, in that picture, you can see YAK nose and IK-3 tail.