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mk4 twin engined spitfire (very whiffy)


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Hmmm... bonkers! (In a "what the hell, do it anyway" fun kinda way) :mental:

However I feel compelled to foolishly throw the minor issue of reality and basic aero engineering at an otherwise flawless design concept :whistle:

1. torque... if both engines and props are spinning in the same direction then you have a bit of a problem.... the thing is going to need a hell of a big rudder to overcome the tendancy (i.e. obsessive tendancy) to roll (which the spit had a bit of a problem with anyway).

OR

if they are counter rotating (It looks like the rear prop is round the right way for this?) then the airframe is going to suffer from lots of torsional loads as the two engines try to turn your spit into a twisler! So you'll need more structural strengthening and hence increase weight and this will affect the next point:

2. Wings: Your wings (and their counter ballance of the horizontal stabilisers) need to be bigger. Sure at speed they may generate enough lift to keep the huge extra weight of an additional engine, prop-shafts, double the fuel etc in the air, but...... full speed isn't really the limiting factor, it is the stall speed and low speed handling that are an issue (as presumably unlike some german designs this aircraft is intended to be used more than once?) and therefore need to be able to land! Also as you get to higher altitude your increased wing loading is going to affect the performance envelope and make her as twitchy as a twitchy thing! Presumably the pilots will get lots of spin recovery training! ;)

Also the wing tip extensions aren't going to add much because the majority of the eliptical plan-form wings lift is generated in the first 3/4 of the span and the tip doesn't generate that much - hence why late spits got away with shortened wing tips.

3. Fuel: where are you putting the extra fuel tanks? the wings are full of machine guns/cannons and their respective ammo stores as well as the current tanks. if you put them in the rear fuselage how are you protecting them from gunfire? if thats more armour then again you have greater weight... see point 2! also that would alter the center of gravity and so you'd need to move the wings a bit so that the relationship of the CoG to the Centre of Force of the wings is maintained with the original spit.

4. Also if the rear fuselage is mostly engine, prop shaft and fuel, where is the radio gear going?

Still apart from these minor reality issues its great! :thumbsup:

Edited by Flying Badger
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Imagine the take off run : "V1.....VR.....bugger!" Might be worth re-thinking the undercarriage arrangement as there isn't much clearance for the rear prop blade.

Love the concept

and the merge!

Hmmm... bonkers! (In a "what the hell, do it anyway" fun kinda way) :mental:

However I feel compelled to foolishly throw the minor issue of reality and basic aero engineering at an otherwise flawless design concept :whistle:

1. torque... if both engines and props are spinning in the same direction then you have a bit of a problem.... the thing is going to need a hell of a big rudder to overcome the tendancy (i.e. obsessive tendancy) to roll (which the spit had a bit of a problem with anyway).

OR

if they are counter rotating (It looks like the rear prop is round the right way for this?) then the airframe is going to suffer from lots of torsional loads as the two engines try to turn your spit into a twisler! So you'll need more structural strengthening and hence increase weight and this will affect the next point:

2. Wings: Your wings (and their counter ballance of the horizontal stabilisers) need to be bigger. Sure at speed they may generate enough lift to keep the huge extra weight of an additional engine, prop-shafts, double the fuel etc in the air, but...... full speed isn't really the limiting factor, it is the stall speed and low speed handling that are an issue (as presumably unlike some german designs this aircraft is intended to be used more than once?) and therefore need to be able to land! Also as you get to higher altitude your increased wing loading is going to affect the performance envelope and make her as twitchy as a twitchy thing! Presumably the pilots will get lots of spin recovery training! ;)

Also the wing tip extensions aren't going to add much because the majority of the eliptical plan-form wings lift is generated in the first 3/4 of the span and the tip doesn't generate that much - hence why late spits got away with shortened wing tips.

3. Fuel: where are you putting the extra fuel tanks? the wings are full of machine guns/cannons and their respective ammo stores as well as the current tanks. if you put them in the rear fuselage how are you protecting them from gunfire? if thats more armour then again you have greater weight... see point 2! also that would alter the center of gravity and so you'd need to move the wings a bit so that the relationship of the CoG to the Centre of Force of the wings is maintained with the original spit.

4. Also if the rear fuselage is mostly engine, prop shaft and fuel, where is the radio gear going?

Still apart from these minor reality issues its great! :thumbsup:

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1 engines and props are counter rotating so much less torque steer than the real thing (it is strengthened but the whole point of the plane is a short term point defence interceptor using the same design philosaphy as the lightning)

2 wings are a bit bigger and tips are extended its meant to be a high performace interceptor so twitchy isnt always a bad thing

iv also moved the wings back to deal with a cog change

3 drop tanks and any available space

4 wherever it fits lol

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what do i do regards weathering for the guns? theres a hole under each gun on the bottom of the wing are these gas vents? ie would you get a streak of crap fro there toward the trailing edge of the wings?

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MK4 SPITFIRE

by 1943 it was obvious that war with germany was at the very least quite likely. the main fighter/interceptor in raf service was the mk2 spitfire with a 1600 hp merlin engine with 2x20mm cannons and 2x .50 cal mgs.
the new mk3 spitfire with 4 cannons and a new more powerfull griffon engine were beggining to enter service but it was felt that someting more extreme was needed to combat the rumoured jets that tha allies thought germany were developing.
the gloster meteor wasnt progressing as quickly as hoped and a stop gap was proposed to keep pace with these wonderweapons.

the supermarine design team decided to put to new griffon 64 engines (2350 hp each) into a spitfire inline this gave over 3 times the power of the mk2 variant with no noticable increase in drag this resulted in superb performance with an astounding top speed of 560 mph (which was even faster than most of the german jets!).
coupled with 4 hispano cannon this interceptor version went on to serve well into the jet age on equal footing

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As mad as a bag full of woverines in a tumble drier!

Still nicely done that man.

re: holes under the guns in the wing - aren't they for the spent cartridge cases?

TFB

i think they are yeah

im pretty happy with the build because i did alot of chopping and filling etc.

nmf and photos both show EVERY imperfection

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I like it...!!! A nice bit of wiffery there....... :goodjob:

Regards,

ggc

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