C-2 Greyhound Replacements: N-G Greyhound 21, Fokker F.28, MDD C-9 and others

Gerard31956 said:
More artist impression of the Fokker F28 COD. They, Fokker, even did trials with the UK to see if the F28 pilots could do a carrier approach.
f-28 -10.jpg
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The photo looks odd to me:
- angle of attack is too low
- airbrakes not deployed
But if they were doing an approach-only test (i.e. fly the ball, then veer off before landing) it makes more sense.

The brochure scans you quoted were originally published on this forum, by me. You can find the full brochure earlier in the thread.
 
Hobbes said:
Gerard31956 said:
More artist impression of the Fokker F28 COD. They, Fokker, even did trials with the UK to see if the F28 pilots could do a carrier approach.
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The brochure scans you quoted were originally published on this forum, by me. You can find the full brochure earlier in the thread.
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Do you mean the pdf in #12 ? That is a dead link!
 
thanks. found it. never seen that before. I recall seen the original magazine with the F28 COD story back in the 60/70s All the pictures
I posted I found a few years ago on the WWW
 
The missing PDF from #12 (Flight Global article), and a FlightGlobal story about Fokker's pilot training program including a carrier approach in the flight sim.
 

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Hobbes said:
The photo looks odd to me:
- angle of attack is too low
- airbrakes not deployed
But if they were doing an approach-only test (i.e. fly the ball, then veer off before landing) it makes more sense.
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I would also not rule out an approach and wave off having been flown but these photos look fake to me. YMMV.

Happy to be corrected as I only did a cursory search but a Fokker F.28 has a wingspan of 23.6m (or worse) and an Invincible has a flightdeck 16.8m wide. So unless they were going to redecorate the island......

That's also quite the bunt between photos. I'm also curious as to when Fokkers stopped casting reflections/shadows. You would think someone would have filmed it from the deck? Not convinced a Vinnie would be that representative of a CVN anyway.
 
What you all are missing in the pictures is the fact that the F28 is not aiming for the flight deck. It is at least 30 m left of the stern. The flights were to prove that; The pilots could see the carrier and make a visual approach. They are aiming for the point a US carrier would have the deck. IMHO
 
Opportunistic Minnow said:
I would also not rule out an approach and wave off having been flown but these photos look fake to me. YMMV.
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The shot of the aircraft aft of the flightdeck I can believe. The first one, something just looks badly off about the perspective. The F28 clearly can't be anywhere near the deck on clearance and structural grounds, but it doesn't look like it's close to the camera either. It's possible that the small size of the F28 is making it look like it's further away than it actually is....

The less said about the Shackleton that allegedly lined up an approach on a USN carrier then started feathering props, the better....
 
Gerard31956 said:
What you all are missing in the pictures is the fact that the F28 is not aiming for the flight deck. It is at least 30 m left of the stern. The flights were to prove that; The pilots could see the carrier and make a visual approach. They are aiming for the point a US carrier would have the deck. IMHO
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If that were the case then this event is being rather over-sold. At what kind of offset does a simulated approach become a simple dirty pass? You'd be pretty far removed from anything instructional or of real value. So a simple marketing stunt that could be accomplished by any aircraft really.
 
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The intent was to see if this aircraft can follow the approach path as indicated by the carrier's optical landing system with sufficient accuracy. They did tests on a fixed runway as well, this particular test provided an extra datum point by providing a moving target instead of a stationary one.
Fokker was trying to sell these aircraft, so it's not unexpected for them to use the photo opportunity.
 
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Hobbes said:
...follow the approach path as indicated by the carrier's optical landing system....
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How did it follow the meatball if it's offset? If it's not offset, how did it avoid crashing into the island?

When did the Invincible class use a USN OLS?

Pretty sure the majority of CVS landing-ons were from the side.....

Edited to add: This video may be informative:

View: https://www.youtube.com/watch?v=f5h1g1T46LU
 
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Translation of the Spanish article in post #80:

F28 testing for aircraft carrier service in the North Sea

Fokker's chief pilot praises the aircraft's approach behavior

A Fokker F28 Mk6000 has demonstrated important aspects of its suitability for carrier delivery services for the US Navy during recent tests in the North Sea.

Piloted by Henk Themmen, head of Fokker's flight department, the aircraft made several approach passes to an aircraft carrier to check flight path control and stability in this phase of operations. No landing was made, as the emphasis was mostly on handling and maneuverability during approaches, although Themmen later said: 'The sea was calm and the ship had virtually no vertical movement, and I could have landed quite easily in the length of the aircraft carrier deck.

'But that was not the purpose of the tests. In operations related to aircraft carriers, it is very important to have an easily controllable low approach speed, as well as very good stability, so that the control of the flight path does not present complications. The Mk6000 meets both requirements.

'The aircraft also has a very steep lift curve and a very large angle of attack margin, so that with only small changes in the attitude of the aircraft, immediate changes in the angle of the flight path can be achieved. This means that a very controlled approach can be made towards the aircraft carrier.

Fokker has shown the US Navy the performance characteristics of the F28 and the modifications that are needed to adapt it to operations of delivery of material to aircraft carriers. Once modified for this mission, it could be easily adapted for tanker missions and other tasks performed by embarked aircraft.
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A Fokker employee is quoted saying they tested approaches to the carrier. You claim they couldn't possibly have gained useful information from those flights.

Without knowing far more detail of the test than was published, there's no way for us to tell. So I'm going to take Themmen's word at face value.
 
Hobbes said:
You claim they couldn't possibly have gained useful information from those flights.
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That the aircraft could be handled down to VMin would have been established during the initial flight test programme. That it could do so again over water with a grey floaty thing within visual (but not close enough to affect aerodynamics because of clearance-splashy-death issues) should not be new information.

Also, correct me if I am wrong but the F.28COD was to have a new wing, in addition to new nose-gear and a hook so the approach alpha and general handling would be sufficiently different to render this exercise superfluous. I guess it comes down to what you define as useful.
 
Opportunistic Minnow said:
Hobbes said:
You claim they couldn't possibly have gained useful information from those flights.
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That the aircraft could be handled down to VMin would have been established during the initial flight test programme. That it could do so again over water with a grey floaty thing within visual (but not close enough to affect aerodynamics because of clearance-splashy-death issues) should not be new information.

Also, correct me if I am wrong but the F.28COD was to have a new wing, in addition to new nose-gear and a hook so the approach alpha and general handling would be sufficiently different to render this exercise superfluous. I guess it comes down to what you define as useful.
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I think its called 'marketing'
 
Well I think you could argue the point that an existing wing with a wing-fold is in fact a new wing but that might be straying into semantics. I'm certainly satisfied that the prototype is representative of a carrier capable variant in only the barest, barest sense and likewise the carrier.

If the point was to simulate a meaningfully typical carrier approach rather than play-acting, then I would have expected some more alpha over the fantail. Does the below look like a "trapable" attitude to anyone? Perhaps Fokker should have hired an old Sea Hawk driver? Certainly any actual CarQuals would have benefited from some pros.
Gerard31956 said:
f-28-10-jpg.668395
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Again, the point was to test carrier approaches without an actual landing. So the interesting part of the test ends a few hundred meters aft of the carrier, where they'll break off the approach and veer to the left to avoid the carrier and pass it on its left. This photo is taken after the breakoff maneuver.
 
Do you know that for a fact or are you spitballing? It is at least equally likely that the approach is flown at a lateral offset down to a simulated floor alongside the carrier as posited in post#89. If they have indeed aborted their approach long before coming alongside, why are they alongside at all, in a nose down attitude no less? Surely they would abort vertically and avoid any lateral manoeuvrers, much like the procedure they are supposedly emulating?

If the test ends hundreds of metres astern, do the tests even need a carrier?
 
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Opportunistic Minnow said:
If the test ends hundreds of metres astern, do the tests even need a carrier?
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The tests would need a moving OLS/something-else-to-aim-for. The moving target could be on a public road (a bit scary for passing terrestrial traffic) or on a runway of sufficient length. Neither would speak to the imagination as much as the approach of Invincible. Very useful as a test? Don't know. The picture made me smile.
 
I'm done arguing about this. We have one source quoting the pilot involved who says they did a useful test, and on the other hand someone arguing from a single photo that the test couldn't possibly have been useful. Without access to company archives, we won't get any further.
 
'The sea was calm and the ship had virtually no vertical movement, and I could have landed quite easily in the length of the aircraft carrier deck.
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Whaaaat he said ? an Invincible is 210 m long; even with some wind to slow it down, can a Foker F28 really land on such short distance ?
 
Ship sailing windward? Would increase wind over deck speed. Invincible would have been able to reach 28 knots. Add wind speed.
 
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Not the ship, the F28. I meant sustract the ship speed from the F28's.
Drats, you said it better than me.

So I reformulate my question: can a F28 land in 200 meters with 28 kt of wind sustracted from its speed ?
 
... as well as the velocity of the wind the carrier is sailing into. Subtract 50 kts in total? 60? An F28's landing speed was something like 110 kts. I don't know.
 
Me neither. What's the ordinary landing distance of a F28 ? Can't see how it could be less than 1000 m, and cutting that to 200 m gets into STOL territory - think YC-14 / YC-15.
 
1,000 metres slowing down from 110 knots. Slowing down from 55 knots, taking into account wind over deck, should be much less. Time to dust off old school physics. You would need something in the order of 0.25G deceleration from 55 kts speed relative to deck not to land in the drink.
(edit) Invincible's flight deck length 168m. At 0.25G deceleration from 55 kts, landing distance is slightly over 160m. No margin for error. Required 55kts wind over deck creates turbulence around ship's superstructure, raising controllability issues. If Invincible is at 28 kts max speed, required wind speed 27 kts - wind force 6 on Beaufort scale.
In short, touch and go might be possible. Landing isn't.
 
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Archibald said:
Me neither. What's the ordinary landing distance of a F28 ? Can't see how it could be less than 1000 m, and cutting that to 200 m gets into STOL territory - think YC-14 / YC-15.
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Ordinary landing distance is specified at about 1000 m, which should be with a full payload and no wind, at the kind of deceleration airlines are comfortable with. The other end of the spectrum is a 'maximum energy stop', which is only done in emergencies and during the certification process: plane at MTOW, abort the takeoff at V1, brake as hard as possible. - for certification this must be done without a fire breaking out, usually the wheels will get hot enough to trigger the overpressure valve in the tires so you'll end up with a bunch of flat tires.

Found a landing chart:
lc42.JPG


So at light weight and a 40kt headwind (28kt ship speed plus a moderate 12kt wind) gets you down to 1500ft of 'normal' runway required.
 
I'm not sure that I understand today's issue.

My guess is that mock approaches to the Invincible were made primarily because the latter was in the neighborhood and available for practicing approaches (and for publicity photos). I doubt that these tests would be expected to provide a lot of practical data.

Nor do they undercut the idea of using the F28 from US carriers: the flight deck on the USS Nimitz is ~333 m or just under 1100 ft long. The F28 COD would no doubt have had an arrestor hook. Its size and weights were generally comparable to those of the A-3 which operated more or less successfully from smaller carriers than Nimitz.
 
I readily agree with the above -yet the pilot said he felt he could have landed on Invincible... which sound doubtful.
 
See reply #94
Piloted by Henk Themmen, head of Fokker's flight department, the aircraft made several approach passes to an aircraft carrier to check flight path control and stability in this phase of operations. No landing was made, as the emphasis was mostly on handling and maneuverability during approaches, although Themmen later said: 'The sea was calm and the ship had virtually no vertical movement, and I could have landed quite easily in the length of the aircraft carrier deck.

'But that was not the purpose of the tests. In operations related to aircraft carriers, it is very important to have an easily controllable low approach speed, as well as very good stability, so that the control of the flight path does not present complications. The Mk6000 meets both requirements.
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Then we had a go at whether Henk Themmen would have kep his feet dry.
 

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