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stilton
6th Oct 2008, 06:12
Just finished 'Joint Force Harrier' which I enjoyed but a couple of questions arise.

The author mentions picking up significant inlet icing in cloud at one point.

Does the Harrier and / or most fighter type aircraft have engine / wing anti ice protection of any kind, e.g. bleed air ?


Secondly, why does the GR7 version have such an oversized canopy, it seems much larger than necessary, when you look at the clearance between the top of the Pilots helmet to the canopy itself.

Seems out of proportion, there must be a good reason ..

Pontius Navigator
6th Oct 2008, 06:20
Interestingly, I am just reading a novel that features AV8a and comments how small the cockpit was and likened it to sitting in a tube rather than the all round vision afforded by the AV8b. Your answer perhaps.

orca
6th Oct 2008, 06:42
The aircraft is a CAS platform. The legacy aspects of this discipline involve a lot of looking out of the window. The size of the transparency helps you keep eyes on the target from medium level, and aids acquisition of the target from a low level profile.

FB11
6th Oct 2008, 16:08
Stilton,

We don't have any anti-icing. For the engine, the first stage is rotating so doesn't collect ice (unlike other airframes whose engine installation has a fixed stator or restricted inlet system prone to icing up.)

Our wings? No icing protection but then again, our wing probably gets more aerodynamic when it gets iced over! (Harrier=glides like a bunch of keys)

As for the canopy - exactly as ORCA says; designed by the USMC who know a thing or 2 about such roles and have blokes built like houses.

It's a great platform to see out of from the medium altitude perspective - quite important in fact.

Glad you enjoyed the book.

CirrusF
6th Oct 2008, 17:46
Lack of de-ice is presumably not going to be much of an issue in the Harrier's operational role, but presumably it becomes a constraint when ferrying them out to overseas deployments?

Flap62
6th Oct 2008, 20:02
Have to say, icing was never a significant problem and we never went out of our way to avoid it.
Worst case was chasing a Tristar up and down the adriatic and picked up sufficient ice to prevent any view out of the front and also sufficient to break the dome on a 9L seeker head!!! Didn't notice any adverse effects on the handling though.

stilton
7th Oct 2008, 05:23
Thanks for the interesting and informative answers, and thank you to the brave and dedicated ladies and Gentlemen operating and supporting these aircraft in demanding and dangerous circumstances.

Heliringer
7th Oct 2008, 09:35
Big canopy needed for the big heads that drive them:}

Just a joke fellas

AdLib
7th Oct 2008, 10:19
Bit confused stilts. Is this a Harrier question or a fighter question?

Pure Pursuit
7th Oct 2008, 14:20
Nice book.

Visited the Harrier mates @ KAF & was thoroughly impressed with them. Cockpit didn't seem particularly large to me, especially when picturing the guys being all kitted up in the seat, but what do I know?!

Particularly liked the references to Crowbar! ;)

FB11
7th Oct 2008, 20:14
Pure Pursuit,

Compared to a Sea Harrier cockpit (for size) or other (anon) UK military jet for visibility, the GR7/9 is top class. Sorry, wrong service strap line - I should have said 'second to none' in case there are those who may get stressed about ownership.

With all the gear on, I can still get a pair of binos, poofter bag and a packed lunch in.

I could just about get a Kit Kat in the FA2 cockpit with gear on. Two finger Kit Kat, not 4 that is.

Glad you approve of the Crowbar reference; something in there for everyone.

AdLib,

I still think I'd just about qualify to answer if there were to be a fighter question...

Heliringer,

I'm a medium broad. Good joke though. Wokka wokka wokka...

FB11

Engines
8th Oct 2008, 19:21
Gents,

AV-8B cockpit is really HUGE by any standards. Lots of clearance and overhangs the fuselage line for maximum visibility. All good.

BUT, a good authority told me that it incurs a speed penalty of around 55kts at max cruise, and there would be a corresponding range penalty. View from my informed friend was that the canopy was an example of a non-optimal trade - too much speed and range lost for the advantages gained. (Interestingly, there were any number of detailed trades on this for the Uk GR5 and the various Harrier III studies. And the Sea Harrier canopy was designed to improve visibility on the approach to the deck, not in air-to-air) Of course, all depends on the role, and if it's 'CAS effectiveness over the target at all costs' then the big canopy wins.

Best Regards as ever,

Engines

GreenKnight121
8th Oct 2008, 23:52
For a CAS aircraft, which is what the AV-8B/GR.5/7/9 are, a high maximum speed may be useful for target area ingress/egress, but is irrelevant while in the target area actually conducting that CAS. The attack runs will be conducted at well below max speed... more like 400 kts (or even less), not over 550.

stilton
9th Oct 2008, 07:18
Yes Adlib, I was asking about the Harrier, but also about modern jet fighters in general, are engine / wing anti-ice systems normally fitted ?

WhiteOvies
9th Oct 2008, 14:53
The Harrier has ducts that run along the front of the wing leading to the reaction control valves (puffers) at the wing tips which steady the aircraft during the hover. Some of the heat from the hot gas that runs along these ducts migrates to the leading edge (BAE and Rolls have done Infra red camera footage looking for hot spots/leaks etc). Of course these ducts are only used when the nozzles are deflected and the butterfly valve is open so no use during flight but I have seen this as being quoted as a de-icing system (it isnt!).

The GR canopy gives a much better view for the pilot and allows some head room for some of the taller aircrew (particularly the RN ones who were used to origami like flying positions in the SHAR). If only the bloody thing would stay shut...:*

szpalko
26th Oct 2008, 17:39
Stilton:

Most canopies are made of thick plastic to protect the aircrew, make it structurally sound. Unfortunately these refract, bend light just like a lens. For ease of argument, lets say the canopy is a sphere of certain thickness, or half of it, sitting on the fuselage. The closer the pilot's head is to the top the more distortion he will encounter. If he sits in the geometric centre, he will see minimal distortion. Designers thought that the way this craft operates, accurate visual assessment of the outside is more important then better streamlining.
Very important with airborne optical devices as well. Take a look, almost all of them have a spherical dome and the device is centred in the middle.