Amazing RC Jets

[Spitfire]

This is incredible flying with a plane of that size and speed ... the final approach and landing is just amazing



This plane is also brilliant - just love those 'afterburners' - very effective The cameraman needs a tripod - but its mostly ok - and again a superb landing



I think this is the same plane in a bit more detail - lovely model (The field and tarmac runway layout looks identical - but no sign of afterburners )



Nice model - I love the shape of Phantoms - Again a greaser of a landing at speed

[Xplumberlives]

Thanks for posting those, that A10 is extremely impressive and so nice to see a model carrying ordnance! I wonder if a working cannon could be fitted?

Only one thing spoilt that display, the speed at which the model was taxied back up the runway was far too fast!

Second SR71 has a different paint scheme!

Why did the phantom suffer from a back seat ejection?

[Spitfire]

I wonder if a working cannon could be fitted?

Only one thing spoilt that display, the speed at which the model was taxied back up the runway was far too fast!

Best I could do

Yeah - you can't scale speed easily - it's like watching large model battleships bobbing up and down on the smallest of ripples

[Xplumberlives]

I love small ripples!

[Thumper]

Wow I LOVE the Warthog thats the best RC plane I have ever seen, so realistic and superbly flown!

The Phantom take off was wierd, I thought it as gonna come down when he first lifted off!!

I love this large P-51 with retractable landing gear



Thrust vectoring Jet Typhoon with a REALLY annoying commentator



An SU-37 with thrust vectoring too



Finally this is just cool

[Xplumberlives]

Thumps, the Toom was on it's FIRST flight!

[Spitfire]

Retracts on big scale stuff are pretty much standard now - but what's needed for us pedants is PROPER asymmetric retracting as in a full scale Spitfire......One wheel up and stowed seconds before the other


My model making mate has been working on this - but its not easy in model making - the only real way you'd do it is 2 separate servos and one geared slightly differently to the other - but that adds weight

Using one servo or air retracts normally leads to symmetrical retract or at best none adjustable and random asymmetry.

Don't want much do I

[Dan4th]

One servo, two different gear links....

D.

[Sooty655]

One servo, split linkage, excess slack on one side, spring loaded over travel on the other.

[Dan4th]

Like I said............

D.

[Pujgnie]

......One wheel up and stowed seconds before the other

Always intrigued me as to why Spitfires had that trait.

[Saracenman]

i believe it's because the pneumatics are laid out such that one leg is closer to the air reservoir than the other, ergo the closer leg retracts first

sm

[Xplumberlives]

Are they designed to move one before the other or is it traight of the pipework?

[Saracenman]

not a design feature, just accidental - all to do with the plumbing

i believe they extend largely due to gravity, so the delay only occurs with retraction

sm

[Xplumberlives]

I suffer in much the same way!

[Saracenman]

but unlike RJM's finest, that's just AGE!

sm

[Xplumberlives]

Indeed!

[Spitfire]

Never really thought about it - its always been - well - just SPITFIRE to me

But a bit of noodling around has come up with some snippets.......

The Spitfire undercarriage was hydraulic, and I suspect there was one pump driving the rams in each leg through a common circuit. Manufacturing tolerances will ensure that the ram on one leg will have less friction than the other, and will move first. I don't think any asymmetry in operation was by design.

Interesting to know that the earliest Spitfires didn't have a powered hydraulic pump, the pilot had to fly with his left hand and hand pump the gear with his right!

The DC-3 MLG retracts in the same manner as its run off one pump and its usually the leg nearest the pump in use (it has two but only one is in use at a time) that retracts first. FYI the MLG on the Spit blocked the airflow to the radiator so it was important to retract the MLG quickly after take off.

I have a copy of AP1565B (1943) for the Spitfire Mk II A & B - which includes the maintenance notes. Sect 4 Chap Fig 5 shows a schematic of the hydraulic system. It has a single, engine driven, pump which acts directly on the two main undercarriage jacks through the undercarriage control unit in the cockpit. Neitther there or in the flying notes is there any mention of sequencing, nor in the ground test schedule which goes in to some detail on the checking process.

We're an operator.....one MkV and an XIV; there is no sequencing, just one pump and two legs. If there is a retractable tail wheel that will go first. The pump is on the right hand side and it's usually the right leg that raises before the left one.

It seems that last one is the definitive answer as it matches with the bit in red above and it comes from an actual operator. Also if you look at the next clip of the Grace 2 seater - and I've never noticed - it is the right one stowed first



SIMPLES

[Xplumberlives]

Thank you P1

[Saracenman]

a Spit's undercar is hydraulic?

i always thought it was pneumatic! well, one learns something new every day!

sm

[Spitfire]

Nah - the flaps are pneumatic - which is why the are only up or down and they are quite 'aggressive' when selected - a big hiss and down they go

The Spitfire flap extends to 85 degrees. There are only two positions - up or down and no intermediate stages. The flaps are lowered using pneumatic pressure and raised using spring cartridges. During the war carrier based Spitfires and Seafires would often use a wedge of wood to provide a small amount of flap which was dropped out after take off by lowering the flaps.

P N E U M A T I C S Y S T E M
The pneumatic system in the Spitfire is charged to a pressure of 300 lb./sq.in. by an engine driven pump.
This system drives the flaps, radiator flaps, supercharger control and brakes. If the pressure falls below 100
PSI, the flaps will not deploy and the radiator flaps will remain in whatever position they are at the time of
failure. If the supercharger is in high gear it will return to low gear. Below 50 lb./sq.in. the wheel brakes
will fail.

The Spitfire undercarriage system is very simple but clever using a combination of chain, cable and hydraulics to lock, un lock and move the legs.

Really must get one of these........

[Sooty655]

The effect isn't caused by there only being one pump. It is the configuration of two rams hydraulically connected in parallel but mechanically separate that does it.

The vulcan bomb doors are exactly the same - they start and finish together but during travel they do not match position. The effect is most pronounced when using the (single) electric emergency pump. but the same thing happens with three engine driven pumps running, it just happens faster.