1/32 Seafang from Iconicair

[stona]

I've had a chance this morning to fit the wing tips. I did toy with the idea of having them folded as this was a feature of the Seafang (as opposed to the Spiteful). They did, and still do, require some work for a nice neat fit but they can be made presentable.






I got bored with them so stuck on the magnifier and started on some of the very small cockpit parts. Here's the rudimentary assembly for the rudder pedals.






I have never seen a photograph of a Seafang cockpit and know of only two of the Spiteful cockpit, which means that most of this cockpit detail is going to be an educated guess by the folks at Iconicair. I won't be worrying over much about that and will only add a Sutton QS harness (the later type with the parachute type quick release box). That harness will be my educated guess, as will be how and where the various parts attach A safe bet with this aircraft is to base anything you have to guess at on a late Mark Spitfire/Seafire.


Cheers


Steve

[Snowman]

little booklet is very well drawn with clear views

I do appreciate well illustrated guides myself. Maybe its the draughtsman in me..?

[flyjoe180]

Contra rotating propellers were used on various carrier aircraft as they largely eliminate both the torque effect and other undesirable aerodynamic issues which arise fromthe differing slipstreams over the different sides of the aircraft (particularly the inner wing area) caused by a single propeller.

Contra-rotating propellers do indeed largely eliminate aerodynamic effects of high power application at lower speed, but the effects are not due solely to air flow over the fuselage or inner wing. The larger the blades, the greater the effects of aerodynamic forces on those blades for any given RPM. Asymmetric blade effect, gyroscopic effect, etc. (remember school physics, precession?). Contra-rotating propellers are largely about absorbing power, increasing the solidity of the propeller disc (Avro Shackleton comes to mind). If you don't absorb increased power output with more blades or contra-rotating blades, you have to increase the chord of the propeller blades (the Germans were of this mind it would seem, some of those late war German types look like they had very large-chord blades).


As you say Steve, no doubt the Sea Fury could have benefited from contra-rotating blades, it had a massive engine swinging a massive five-bladed propeller. Must have been a real eye opener for new pilots doing conversions


Like you statement about resin kits, I know nothing about the substances so it it good to read that many of the comments out there are not true.


Great looking kit, will watch with interest.

[stona]

Yes, it's a combination of several factors. I think Commander Mike Crosley DSC, RN can explain far better than me!


"Pilots found that the extra 1000hp of the Griffon VI, turning the other way to a Merlin, gave far more torque reaction. This was because of several factors, not just the increased engine power. First, the propeller was twisting the air stream far more than in the Merlin engined version, for it had to absorb nearly twice the power in a propeller of the same diametre and at the same rpm. Second, the 'three point' unstick incidence of the Seafire XV was greater and nearer the stall, owing to the longer stroke oleos. Third, the aircraft weighed a ton and a half more than the Seafire III, and therefore needed to unstick at a higher airspeed than the Seafire III. The static torque from the engine attempting to turn the aircraft in the opposite direction to the propeller was not the main reason for the trouble at take off, for the torque on its own could be easily corrected by upfloating the port aileron a couple of degrees. It was only equivalent to a 200lb weight on the port wing abreast the outer gun, and was not serious. The main cause of the 'right wing low' at take off, or 'torque stall' as it was wrongly called, was a partial stall of the entire starboard wing. With two tons of lift on the port wing and very little indeed on the starboard, it was small wonder that the aircraft carried out a full half turn of a spin to the right, on unstick, on occasion.


At the moment of unstick, if the aircraft was wrenched off at maximum incidence, both the wings would be very near stalling incidence. The slightest dissimilarity in their airflow would upset the balance of lift between the port wing and the starboard - too great to correct by aileron. In the case of the Seafire XV, the starboard wing root stalled first as it was subjected to greater slipstream incidence. This stall then spread outboard, until the wing started to lose lift. The starboard wing then started to drop and in doing so increased its incidence yet more, and fully stalled. Attempting to raise it with aileron would make matters worse.


In the case of 'minimum distance take off' on the flight deck when the pilot was pulling back on the stick to get off as soon as possible, the starboard wing might not establish a proper airflow, and therefore lift, at all.


Once the starboard wheels steadying effect was gone as the aircraft left the deck and flew over the ship's bow, it was inevitable that it spun to the right, into the sea, right in the path of the carrier. Further causes of this problem might have been a gyroscopic 'kick' to the right as the pilot pulled the nose up too sharply on unstick.......


It is interesting to note that the Blackburn Skua had a lift spoiler fixed to its leading edge on its down going propeller side, to equalise the stall characteristics between port and starboard wing when power was on."


Cheers


Steve

[flyjoe180]

Interesting reading Steve, cheers. Remarkably cunning solutions. I'm intrigued that modern turboprop aircraft don't use contra-rotating blades as they are limited in speed by propellers, and it also eliminates the critical engine scenario in multi-engined aeroplanes. Anyway, don't want to digress from your kit build

[Robert1968]

Hi Steve reading and catching up its your progress on this I thought I'd have a look through my saved pics and I have found only one relating to a Supermarine Seafang. It's a bit grainy and b/ w but wondered if this helps

[stona]

Thanks Robert. I have that as one of the two supposedly of the Spiteful, which would be more or less the same as the Seafang.


Cheers


Steve

[rickoshea52]

Interesting reading Steve, cheers. Remarkably cunning solutions. I'm intrigued that modern turboprop aircraft don't use contra-rotating blades as they are limited in speed by propellers, and it also eliminates the critical engine scenario in multi-engined aeroplanes. Anyway, don't want to digress from your kit build

Interesting discussion on propeller torque, I'll remember to ask a Bomberdier rep next time I am with a Q400 operator. But have you noticed the propeller blades on the A400M and their direction of rotation?

[flyjoe180]

Interesting discussion on propeller torque, I'll remember to ask a Bomberdier rep next time I am with a Q400 operator. But have you noticed the propeller blades on the A400M and their direction of rotation?

No I'm not up with the A400M Rick, they have contra-rotating blades though? Which of course would make every engine 'critical' so to speak.


Sorry Steve!

[rickoshea52]

No I'm not up with the A400M Rick, they have contra-rotating blades though? Which of course would make every engine 'critical' so to speak.
Sorry Steve!

The propellers on each engine rotate in opposite directions.

[flyjoe180]

The propellers on each engine rotate in opposite directions.

Yep, they would being contra-rotating?

[stona]

Sorry Steve!

It's all interesting stuff, so absolutely not a problem! I quite enjoy these tangents and they break up the build thread very nicely in an educational way


Cheers


Steve

[stona]

This morning I've built the seat, which was interesting, and attached it to the relevant fuselage frame.






The white plastic card is armour plate (I assume) which is a part shown in the instructions but which isn't in the kit, unless I've lost it! Anyway, it was a fairly simple job to make the piece from some suitable card. The grubby black marks are the remnants of the markings used to make the holes through which the seat supports pass to their mounts and will disappear later.


I've also done the front part of the cockpit assembly and am just waiting for the paint to dry on the instrument panel before assembling that.






I hope to get more done tomorrow.


Cheers


Steve

[Snowman]

I've noticed that a number British Naval kites have contra rotating props - there is probably a performance benefit to justify the design requirement.o_O

[stona]

Not much exciting progress to report. I've spent considerable time cutting out parts to drop in the various camera ports and making them fit, hopefully without needing much filler.Trickiest was the door with a round hole to be glazed in the fuselage half at the top of this image. The part with the two holes to be glazed was fitted by first cutting out the relevant section of each fuselage half, taping the two halves together, and the shaving, filing and sanding until it dropped in nicely.






Apart from that I've made a load of cockpit sub-assemblies and sprayed them a basic black. They will obviously need some detail painting and general jazzing up before everything gets fitted into the fuselage.






Next, assembling the RB Productions harness, if my eyes can take the strain


Cheers


Steve