Spitfire cowling details

[Springer6]

Yes I think that on all marks of Spit , the flaps were LOWERED by the use of compressed air from the same source as for the brakes. I don't know how long it takes , but it can only be a matter of a couple of seconds. ( I'll try to time it,  next time I see a Spit on approach, but it will probably be too distant).

The flaps are RAISED by releasing the air to atmosphere via the flap control valve and the flaps are then raised by a spring box attached to each flap, assisted of course by the slipstream if the a/c is in flight or  ground running .This spring return, I would have thought, would be fairly quick.

The undercarriage is raised and lowered by a hydraulic system and speed of operation is therefore dependant upon the speed of the engine driven ( or manual for early a/c ) pump. Therefore for take off, speed of raising is fairly quick for non manual systems , but can be quite slow for lowering if the pilot leaves dropping  the chassis until  late in the approach with the  consequent low engine speed. In an emergency the undercarriage could be lowered ( but not raised) by discharging the contents of a Carbon Dioxide bottle into the downside of the operating ram. In any case I don't think that the lowereing undercarriage would give the initial nose lift that lowering flaps might.

[Hagar]

[quote]The undercarriage is raised and lowered by a hydraulic system and speed of operation is therefore dependant upon the speed of the engine driven ( or manual for early a/c ) pump. Therefore for take off, speed of raising is fairly quick for non manual systems , but can be quite slow for lowering if the pilot leaves dropping

[ozzy72]

As the flaps are lowered they should give a brief second or two of lift whilst getting to the down position, then they really are airbrakes!
Another thing to remember with the U/C down is overheating as the U/C disrupts the airflow to the radiator(s)/oil-cooler, so you can only have them down for a short time before your Merlin starts cooking

[Springer6]

Yeah ,

I think the drill was raise flaps on landing as you slowed to a fast walking speed . Five shillings fine at Operational Training units for taxiing with flaps lowered and another five shillings fine if you boiled the glycol coolant as a result!

[Hagar]

Another thing to remember with the U/C down is overheating as the U/C disrupts the airflow to the radiator(s)/oil-cooler, so you can only have them down for a short time before your Merlin starts cooking

I think this is only while they are in transit. If they jam half-way, as they often did, you have problems.

[ozzy72]

I read of a case of a Seafire III in the Med having to do an emergency deck landing with a U/C jammed down problem and the engine was cooked by the time he got on the deck after having flown only a couple of circuits...

[Springer6]

A Shuttleworth Collection pilot , Neil Williams , in describing his experience of flying the collection's MkVc says that with the single radiator models , even taxiing slowly causes coolant temprature to rise alarmingly as the starboard undercarriage leg is masking the radiator .

[C]

Lowering flaps will result in a nose down pitch in most aircraft (rearward movement of the CofP?) - I'll go and have a look at the XVI pilots notes in a min and check. Lowering the U/C should also produce a slight nose down pitch as they move forward relative to the CofG...

[Springer6]

At Old Warden yesterday , I had a chat with a pilot who flys their Spitfire VC ( now fitted with standard wing tips as opposed to its original clipped wings ).

He confirmed that lowering the flaps causes a nose down change of pitch. He was unable to say exactly how much as he automatically holds it on the stick whilst trimming out. He felt that lowering the undercarriage caused very little if any change of pitch.

On speed of deployment, he said that if tested on the ground the flaps would deploy "bang instantly" under pneumatic pressure, but in the air when acting against the airflow they would take "a second or two". The flaps powered by their return springs raised equally quickly.

A mechanic , who works on the Spitfire, confirmed that the cowling detail shown in Rifleman's photo was indeed to direct airflow over the Merlin's generator. He pointed out that the Collection's Sea Hurricane also had a similar if less obvious air pick up on the port cowling.

Another pilot who had flown both types pointed out that the Hurricane was very much less prone to overheating than the similarly engined Spitfire , due to it's larger centrally mounted radiator which is not masked by either flaps or undercarriage.

Another interesting aspect of seeing these two birds fly together at close quarters was the noticable difference in their sounds ( even though they are powered by similar engines and props. The Spitfire has a distinctive "whistling sound" in flight that can be heard above the general roar of the Merlin . I understand that this "whistling" is caused by the air passing through the Morris type radiator. Apparantly this sound was not present with the early Serck type radiators.

The flying aircraft housed at Old Warden range from a 1910 Bristol  Boxkite to a 1946 Chipmunk. The staff are friendly and informative and it's a beautiful location. I recommend a visit.
http://www.shuttleworth.org/shuttleworth/index.htm

[Hagar]

I was at Old Warden yesterday & also spoke to a pilot on this subject. He confirmed what you've just written. I was surprised when he said that lowering the undercarriage doesn't usually affect trim a great deal. On the subject of overheating in the air, this is when power is applied with the undercarriage extended as the legs partially block the radiator intake(s).

PS. I really enjoyed yesterday's show. Check out my pics in the Photos forum.

[Springer6]

Great photos Hagar...made up for my rather disapointing results.

[C]

Is this turning into the Shuttleworth Collection appreciation soceity? First mention of God's own aeroplane, AR501 (even with its "growths" on the wingtips), and then a mention of one of the greatest pilots and air navigators who has ever grace this earth, the late Flt Lt Neil Williams.

Who did you have the fortune of a chat with (that question goes to Doug and Springer (Maurice I take it?))?

Maybe I'll put their link back in my sig, and maybe a plug for the SVAS too...

[Hagar]

Is this turning into the Shuttleworth Collection appreciation soceity? First mention of God's own aeroplane, AR501 (even with its "growths" on the wingtips), and then a mention of one of the greatest pilots and air navigators who has ever grace this earth, Flt Lt Neil Williams.

Who did you have the fortune of a chat with (that question goes to Doug and Springer (Maurice I take it?))?

LOL I was going to ask you that. I'm terrible with names. Chap with receding hair - don't tell him I said that. Name began with an M - could it have been Rob Millinship? He was standing in front of the Gladiator when I grabbed him for a chat. One of the regular pilots although he told me he hasn't flown the Spitfire - yet.

[C]

Sounds very much like Rob Millinship, the "oddball" pilot at the Collection, being a) not current or ex-military and b) not a test pilot, and master aeromodeller of years gone by. Had a nice chat with him at the May show. Felt a bit of a numpty standing in the middle of the flightline with my jeans on though! I was having a discussion at the same show involving a few of the pilots, and the two I knew (from work) were trying to work how long it would take before they would get their hands on the Spit. 7-9 years sounded about average... Having said that, another of the pilots has the hard job of occasionally flying the Sea Fury and Sea Hawk for the RNHF.

[Springer6]

Charlie,

The Shuttleworth pilot who I spoke to was in his mid forties with receding hair, about 5' 9". I didn't get the opportunity to ask his name as he was quite busy on the flightline in discussion with mechanics.

He confirmed that he flew the Spitfire , but was not the chap who flew it later in the afternoon display. That pilot was  a large  military looking guy in his ( late?) fifties with shortish grey hair and a very ruddy complexion.

All the staff, from shop staff to mechanics and pilots were extremely helpfull and friendly. This all contibuted to a marvellous day. It  was my first visit to Old Warden  ( apart from on the Sim. ) and even though it was a 400 mile round trip for me I will certainly be back.