Biggest mistakes in aviation history? Which projects should have been built?

[helmutkohl]

Japan
Original Mitsubishi F-2,

Do you have a picture or description of this?

Here is a 1987 model from Mitsubishi of their FSX, as what the F-2 was known before

source: https://nordot.app/432476021603222625

 

[Justo Miranda]

Reggiane Re 2006

 

[Justo Miranda]

NACA Swept wing Thunderbolt

 

[Justo Miranda]

Jet Thunderbolt

 

[Justo Miranda]

Gluhareff "Dart"

 

[Justo Miranda]

Hurricane Mistel

 

[Justo Miranda]

Martin-Baker M.B. III

 

[Justo Miranda]

Gloster E.28/39 fighter

 

[Justo Miranda]

Jet Mosquito

 

[Justo Miranda]

Arsenal VG.60

 

[Justo Miranda]

Lill Draken (Light fighter version)

 

[Elan Vital]

I'm of the opinion that even if it wasn't suitable for long-term Army needs, the Bell 309 Kingcobra would have been preferable for new production than plain AH-1S variants. There is still a lot of commonality between AH-1Gs converted into AH-1Ses and the Kingcobra, but the latter offered a real night attack capability on top of generally improved performance in other parameters.

Considering we are talking about potentially some 609 airframes (production AH-1S series, Japanese AH-1 and production AH-1W), I think it could easily be financially justified. Moreso since the Apache didn't enter service until about 1984. That's excluding the AH-1T which itself reused many components of the Kingcobra.

 

[royabulgaf]

What if?
During the 1970s, two or more light-weight fighter programs combined their efforts to put one into production.
Yugoslavian Novi Avion, Israeli Lavi, Swiss Pirana, South African early single-engined Carver, etc,
Then more smaller nations could afford to field decent numbers of interceptors with a secondary role of ground attack/scaring citizens into complying with the gov't.

Hmm- SA at that time was a political pariah, and Switzerland and Yugoslavia wouldn't touch them. That leaves Israel to pair up with SA. Clearly some joint work was done here and there, but this was a fairly public project, with US technical assistance and money that would dry up if Israel joined up with SA. I think Switzerland and Yugoslavia would be too fussy to deal with Israel, which also has US strings attached to the Lavi project. Yugoslavia was working at that time with a Jaguar equivalent with Romania, and IIRC Romania was working on something along the Novi lines. Actually a Swiss/Swede co-design would make more sense, as both have similar defense scenarios.

 

[riggerrob]

Lill Draken (Light fighter version)

Minor correction: Lill; Draken was built and flown as a sub-scale prototype to confirm the aerodynamic configuration of the full-scale Draken's double delta wing. Note how the early Lill has a very short nose radome, barely outside the engine intake, while the later version had a regular radome more like contemporary fighters.

 

[riggerrob]

I'm of the opinion that even if it wasn't suitable for long-term Army needs, the Bell 309 Kingcobra would have been preferable for new production than plain AH-1S variants. There is still a lot of commonality between AH-1Gs converted into AH-1Ses and the Kingcobra, but the latter offered a real night attack capability on top of generally improved performance in other parameters.

Considering we are talking about potentially some 609 airframes (production AH-1S series, Japanese AH-1 and production AH-1W), I think it could easily be financially justified. Moreso since the Apache didn't enter service until about 1984. That's excluding the AH-1T which itself reused many components of the Kingcobra.

King cobra would have been most valuable to small air forces that could barely afford one type of helicopter. If Bell built a cargo and passenger carrying UH-1? that shared the same dynamic components as Kingcobra, it would greatly ease logistics, training and maintenance for a cash-strapped small air force..

 

[Archibald]

I'm of the opinion that even if it wasn't suitable for long-term Army needs, the Bell 309 Kingcobra would have been preferable for new production than plain AH-1S variants. There is still a lot of commonality between AH-1Gs converted into AH-1Ses and the Kingcobra, but the latter offered a real night attack capability on top of generally improved performance in other parameters.

Considering we are talking about potentially some 609 airframes (production AH-1S series, Japanese AH-1 and production AH-1W), I think it could easily be financially justified. Moreso since the Apache didn't enter service until about 1984. That's excluding the AH-1T which itself reused many components of the Kingcobra.

Which bring us back (once again) to the Cheyenne, CAS USAF vs Army turf war of the 60's.
Which led to
- AH-56 Cheyenne
- AH-1 Cobra
- A-10
-YA-9
-Bell 309
- Sikorsky S-67
- YAH-63
- AH-64
- A-7F
-A-10B
-AF-16
All this because USAF was only sure about two things, related to CAS
- "It can't be an helicopter"
- "We must piss the Army"

Every single entry in that list was a fine flying machine (except the F-16 gun pod). And a lot of them ended wasted at great taxpayer dollar expense...

 

[iverson]

How about the decision to destroy the production tooling for the A-10? With a higher thrust engine, state-of-the-art FLIR and MANPDS countermeasures, it could remain a central part of the Air Force mission for at least another 2o years (which was, of course, exactly why the tooling was scrapped).

 

[Conspirator]

Lill Draken (Light fighter version)

for some reason i do not see this having hardly any pulling-up-quick capabilities.... (sorry that was blunt.) i see this with the leading edge pulled back and having canards like a Chengdu. it would outperform even an F/A-18

 

[Pioneer]

I'm of the opinion that even if it wasn't suitable for long-term Army needs, the Bell 309 Kingcobra would have been preferable for new production than plain AH-1S variants. There is still a lot of commonality between AH-1Gs converted into AH-1Ses and the Kingcobra, but the latter offered a real night attack capability on top of generally improved performance in other parameters.

Considering we are talking about potentially some 609 airframes (production AH-1S series, Japanese AH-1 and production AH-1W), I think it could easily be financially justified. Moreso since the Apache didn't enter service until about 1984. That's excluding the AH-1T which itself reused many components of the Kingcobra.

Which bring us back (once again) to the Cheyenne, CAS USAF vs Army turf war of the 60's.
Which led to
- AH-56 Cheyenne
- AH-1 Cobra
- A-10
-YA-9
-Bell 309
- Sikorsky S-67
- YAH-63
- AH-64
- A-7F
-A-10B
-AF-16
All this because USAF was only sure about two things, related to CAS
- It can't be an helicopter
- We must piss the Army

Every single entry in that list was a fine flying machine (except the F-16 gun pod). And a lot of them ended wasted at great taxpayer dollar expense...

In which case Archibald, could your list also include the either the Fiat G.91/Northrop N-156F (F-5A)/Douglas A4D-2N?

Regards
Pioneer

 

[Archibald]

I'm of the opinion that even if it wasn't suitable for long-term Army needs, the Bell 309 Kingcobra would have been preferable for new production than plain AH-1S variants. There is still a lot of commonality between AH-1Gs converted into AH-1Ses and the Kingcobra, but the latter offered a real night attack capability on top of generally improved performance in other parameters.

Considering we are talking about potentially some 609 airframes (production AH-1S series, Japanese AH-1 and production AH-1W), I think it could easily be financially justified. Moreso since the Apache didn't enter service until about 1984. That's excluding the AH-1T which itself reused many components of the Kingcobra.

Which bring us back (once again) to the Cheyenne, CAS USAF vs Army turf war of the 60's.
Which led to
- AH-56 Cheyenne
- AH-1 Cobra
- A-10
-YA-9
-Bell 309
- Sikorsky S-67
- YAH-63
- AH-64
- A-7F
-A-10B
-AF-16
All this because USAF was only sure about two things, related to CAS
- It can't be an helicopter
- We must piss the Army

Every single entry in that list was a fine flying machine (except the F-16 gun pod). And a lot of them ended wasted at great taxpayer dollar expense...

In which case Archibald, could you list also include the either the Fiat G.91/Northrop N-156F (F-5A)/Douglas A4D-2N?

Regards
Pioneer

I use to say: the more, the merrier

 

[topspeed3]

Most people here seem to be posting about post-war and jets.

How about these to consider...

The He 112B, or, even better, the He 100D

Martin-Baker MB.5

Focke-Wulf Fw 187 Falke

100D was faster in 1939 than Me-109 in 1945.

 

[tomo pauk]

Most people here seem to be posting about post-war and jets.

How about these to consider...

The He 112B, or, even better, the He 100D

Martin-Baker MB.5

Focke-Wulf Fw 187 Falke

100D was faster in 1939 than Me-109 in 1945.

Was it?

 

[topspeed3]

Most people here seem to be posting about post-war and jets.

How about these to consider...

The He 112B, or, even better, the He 100D

Martin-Baker MB.5

Focke-Wulf Fw 187 Falke

100D was faster in 1939 than Me-109 in 1945.

Was it?

670 vs 650.

 

[tomo pauk]

670 vs 650.

710 km/h for Bf 109K-4.

 

[topspeed3]

670 vs 650.

710 km/h for Bf 109K-4.

729 with 4 bladed prop for 109 K-14.

 

[tomo pauk]

670 vs 650.

710 km/h for Bf 109K-4.

729 with 4 bladed prop for 109 K-14.

Anyway, both are faster than 670 km/h for the He 100D.

 

[giorgos42gr]

Hi everyone
I would love to see the yf23 braught into production more than the f22
I have a soft spot for this plane.
Also Rah66 Comanche

 

[topspeed3]

670 vs 650.

710 km/h for Bf 109K-4.

729 with 4 bladed prop for 109 K-14.

Anyway, both are faster than 670 km/h for the He 100D.

Bulk of the 109 were G-models...which only reached 600 km/h in practise.

 

[tomo pauk]

670 vs 650.

710 km/h for Bf 109K-4.

729 with 4 bladed prop for 109 K-14.

Anyway, both are faster than 670 km/h for the He 100D.

Bulk of the 109 were G-models...which only reached 600 km/h in practise.

In practice, the G-10 did 685 km/h. Same with other Bf 109s with DB 605AS and ASM engines. The 600 km/h Gs were the ones with retricted DB 605A engines (= in 1943) and gun pods.
Also in practice, was there ever such a thing as a He 100D fighters flight-tested by Luftwaffe, or we're left to believe manufacturer's figures? Three MG 17s as firepower, worth 1/10th of what Bf 109 in 1944 was carrying? No protection for pilot and fuel tanks vs. armored windscreen, back armor and self-sealing fuel tanks on the Bf 109.

 

[topspeed3]

670 vs 650.

710 km/h for Bf 109K-4.

729 with 4 bladed prop for 109 K-14.

Anyway, both are faster than 670 km/h for the He 100D.

Bulk of the 109 were G-models...which only reached 600 km/h in practise.

In practice, the G-10 did 685 km/h. Same with other Bf 109s with DB 605AS and ASM engines. The 600 km/h Gs were the ones with retricted DB 605A engines (= in 1943) and gun pods.
Also in practice, was there ever such a thing as a He 100D fighters flight-tested by Luftwaffe, or we're left to believe manufacturer's figures? Three MG 17s as firepower, worth 1/10th of what Bf 109 in 1944 was carrying? No protection for pilot and fuel tanks vs. armored windscreen, back armor and self-sealing fuel tanks on the Bf 109.

No after 50 flying hours Me-109 G was already so worn out that it only managed to 600 km/h. It was built to last 100 hours.

 

[tomo pauk]

670 vs 650.

710 km/h for Bf 109K-4.

729 with 4 bladed prop for 109 K-14.

Anyway, both are faster than 670 km/h for the He 100D.

Bulk of the 109 were G-models...which only reached 600 km/h in practise.

In practice, the G-10 did 685 km/h. Same with other Bf 109s with DB 605AS and ASM engines. The 600 km/h Gs were the ones with retricted DB 605A engines (= in 1943) and gun pods.
Also in practice, was there ever such a thing as a He 100D fighters flight-tested by Luftwaffe, or we're left to believe manufacturer's figures? Three MG 17s as firepower, worth 1/10th of what Bf 109 in 1944 was carrying? No protection for pilot and fuel tanks vs. armored windscreen, back armor and self-sealing fuel tanks on the Bf 109.

No after 50 flying hours Me-109 G was already so worn out that it only managed to 600 km/h. It was built to last 100 hours.

A ha, so now the 109 does 600 km/h, not 650 km/h as you've stated above? In the same time, the He 100 cannot be worn out.
Good to know.

 

[topspeed3]

670 vs 650.

710 km/h for Bf 109K-4.

729 with 4 bladed prop for 109 K-14.

Anyway, both are faster than 670 km/h for the He 100D.

Bulk of the 109 were G-models...which only reached 600 km/h in practise.

In practice, the G-10 did 685 km/h. Same with other Bf 109s with DB 605AS and ASM engines. The 600 km/h Gs were the ones with retricted DB 605A engines (= in 1943) and gun pods.
Also in practice, was there ever such a thing as a He 100D fighters flight-tested by Luftwaffe, or we're left to believe manufacturer's figures? Three MG 17s as firepower, worth 1/10th of what Bf 109 in 1944 was carrying? No protection for pilot and fuel tanks vs. armored windscreen, back armor and self-sealing fuel tanks on the Bf 109.

No after 50 flying hours Me-109 G was already so worn out that it only managed to 600 km/h. It was built to last 100 hours.

A ha, so now the 109 does 600 km/h, not 650 km/h as you've stated above? In the same time, the He 100 cannot be worn out.
Good to know.

Heinkel knew his plane is 80 km/h faster thus he informed Udet about it.

 

[Pioneer]

Have we mentioned the Grumman A-6F Intruder?

This would have offered a capability the USN still lacks to this day (even after the A-12 Avenger II cancellation decision)

The F/A-18E/F still lacks the A-6F's range and offensive payload capability


Regards
Pioneer

Reading over this subject of the A-6F, I guess another advantage of this Intruder evaluation, is the Aim-120 capability that was to be incorporated....Interesting that it would have given the A-6F some degree of 'self-escort' capability in hostile aerospace....

Regards
Pioneer

 

[kaiserd]

Have we mentioned the Grumman A-6F Intruder?

This would have offered a capability the USN still lacks to this day (even after the A-12 Avenger II cancellation decision)

The F/A-18E/F still lacks the A-6F's range and offensive payload capability


Regards
Pioneer

Reading over this subject of the A-6F, I guess another advantage of this Intruder evaluation, is the Aim-120 capability that was to be incorporated....Interesting that it would have given the A-6F some degree of 'self-escort' capability in hostile aerospace....

Regards
Pioneer

The A-6F was horribly misconceived and out of time.
The A-6F would have been and would now be a death trap for its crew, unable to survive against even moderate threats it would have to face in its role.
Extra range/ payload capabilities don’t help you if you are already dead.

 

[steelpillow]

Returning to the main topic, which is serious suggestions for unbuilt projects, I'd suggest the Vought ADAM V/STOL fighter. The Air Deflection And Modulation system comprised a distributed propulsion arrangement with multiple small jet engines sandwiched in a kind of unholy offspring of a narrow-gap biplane and the thick-wing monoplane, all blowing air over large, full-span Coanda flaps to create vertical lift. An outboard tail kept it clear of the highly variable wing wake and jet efflux.
The Vought ADAM would have been a fine competitor to the AV-8 Americanised Harrier, and potentially supersonic to boot. It would have brought the performance of the B.Ae P.1216 a decade or so sooner (if that opportunity had not also been missed). Intriguingly, the final ADAM III and P.1216 designs were almost identical in size and, apart from the propulsive arrangement, general configuration. However (and despite the best efforts of Yakovlev) practical supersonic + VTOL did not arrive until today's F-35 Raptor.
The advantages of distributed propulsion are being re-examined for the clean, sustainable aircraft of the future, be it electric, hydrogen or biofuel: NASA is even building the X-57 Maxwell to check it out.
Was ADAM an idea before its time? Technically, the wind tunnel work had been done and the engineering was otherwise pretty conservative. The only novel issue would have been failure rate among its wingful of small jet engines. Would sufficient excess power to sustain VTOL operation with perhaps one or two engines out have been practicable? We shall never know.

 

[T. A. Gardner]

I'm of the opinion that even if it wasn't suitable for long-term Army needs, the Bell 309 Kingcobra would have been preferable for new production than plain AH-1S variants. There is still a lot of commonality between AH-1Gs converted into AH-1Ses and the Kingcobra, but the latter offered a real night attack capability on top of generally improved performance in other parameters.

Considering we are talking about potentially some 609 airframes (production AH-1S series, Japanese AH-1 and production AH-1W), I think it could easily be financially justified. Moreso since the Apache didn't enter service until about 1984. That's excluding the AH-1T which itself reused many components of the Kingcobra.

Which bring us back (once again) to the Cheyenne, CAS USAF vs Army turf war of the 60's.
Which led to
- AH-56 Cheyenne
- AH-1 Cobra
- A-10
-YA-9
-Bell 309
- Sikorsky S-67
- YAH-63
- AH-64
- A-7F
-A-10B
-AF-16
All this because USAF was only sure about two things, related to CAS
- It can't be an helicopter
- We must piss the Army

Every single entry in that list was a fine flying machine (except the F-16 gun pod). And a lot of them ended wasted at great taxpayer dollar expense...

In which case Archibald, could your list also include the either the Fiat G.91/Northrop N-156F (F-5A)/Douglas A4D-2N?

Regards
Pioneer

In the field of helicopters, the problems with many of the advanced attack ones at the time was they started development and reached prototype status just as the Army found out that all the lessons they'd learned in Vietnam using helicopters were completely wrong for an environment where the likely opponent (eg., the Soviets) had lots of air defense systems.

The Ansbach trials held in Germany using US AH-1's equipped with just 2.75" FFAR rockets and guns proved that the tactics the Army used in Vietnam were suicidal against Soviet air defenses. The helicopters had to adopt totally new tactics, and needed new weapons like the TOW missile.

For the AH 56 Cheyenne, these trials pretty much meant the program was dead. Lockheed had developed the Cheyenne to be a cross between a helicopter and airplane. The rigid rotor system using a gyro assist to tilt the whole assembly while the blades were fixed in pitch was done to allow for high speed and to use the rotor at high speed as a flight control to maneuver the helicopter, the stub wings providing enough lift at high speed to partially unload the rotor from generating lift.
All that meant the Cheyenne couldn't hover in ground effect almost at all. NOE flight was difficult or even in some tighter terrain, impossible to do. The flying above small arms ground fire and using diving attacks with rockets and guns as the Army did in Vietnam, was a sure way to be shot down against light AA cannon and SAM missiles.

That's pretty much why it didn't proceed any further in development, the entire design would have had to been redesigned to make it work.

The YAH-63 proved inferior to the YAH-64 that became the Apache. That Bell's AH-1 has proven viable in combat almost to today says a lot about the original quality of that design.

 

[Elan Vital]

I'm of the opinion that even if it wasn't suitable for long-term Army needs, the Bell 309 Kingcobra would have been preferable for new production than plain AH-1S variants. There is still a lot of commonality between AH-1Gs converted into AH-1Ses and the Kingcobra, but the latter offered a real night attack capability on top of generally improved performance in other parameters.

Considering we are talking about potentially some 609 airframes (production AH-1S series, Japanese AH-1 and production AH-1W), I think it could easily be financially justified. Moreso since the Apache didn't enter service until about 1984. That's excluding the AH-1T which itself reused many components of the Kingcobra.

Which bring us back (once again) to the Cheyenne, CAS USAF vs Army turf war of the 60's.
Which led to
- AH-56 Cheyenne
- AH-1 Cobra
- A-10
-YA-9
-Bell 309
- Sikorsky S-67
- YAH-63
- AH-64
- A-7F
-A-10B
-AF-16
All this because USAF was only sure about two things, related to CAS
- It can't be an helicopter
- We must piss the Army

Every single entry in that list was a fine flying machine (except the F-16 gun pod). And a lot of them ended wasted at great taxpayer dollar expense...

In which case Archibald, could your list also include the either the Fiat G.91/Northrop N-156F (F-5A)/Douglas A4D-2N?

Regards
Pioneer

In the field of helicopters, the problems with many of the advanced attack ones at the time was they started development and reached prototype status just as the Army found out that all the lessons they'd learned in Vietnam using helicopters were completely wrong for an environment where the likely opponent (eg., the Soviets) had lots of air defense systems.

The Ansbach trials held in Germany using US AH-1's equipped with just 2.75" FFAR rockets and guns proved that the tactics the Army used in Vietnam were suicidal against Soviet air defenses. The helicopters had to adopt totally new tactics, and needed new weapons like the TOW missile.

For the AH 56 Cheyenne, these trials pretty much meant the program was dead. Lockheed had developed the Cheyenne to be a cross between a helicopter and airplane. The rigid rotor system using a gyro assist to tilt the whole assembly while the blades were fixed in pitch was done to allow for high speed and to use the rotor at high speed as a flight control to maneuver the helicopter, the stub wings providing enough lift at high speed to partially unload the rotor from generating lift.
All that meant the Cheyenne couldn't hover in ground effect almost at all. NOE flight was difficult or even in some tighter terrain, impossible to do. The flying above small arms ground fire and using diving attacks with rockets and guns as the Army did in Vietnam, was a sure way to be shot down against light AA cannon and SAM missiles.

That's pretty much why it didn't proceed any further in development, the entire design would have had to been redesigned to make it work.

The YAH-63 proved inferior to the YAH-64 that became the Apache. That Bell's AH-1 has proven viable in combat almost to today says a lot about the original quality of that design.

What about the 309 as a potential bridge? I have heard the two-bladed rotor was questionable on this one but was the aircraft just too new to justify starting production in the interim to AH-64?

 

[isayyo2]

Reading over this subject of the A-6F, I guess another advantage of this Intruder evaluation, is the Aim-120 capability that was to be incorporated....Interesting that it would have given the A-6F some degree of 'self-escort' capability in hostile aerospace....

Regards
Pioneer

I think the AIM-120 capability was designed for assisting the CAP at shooting down Tu-22s and their payload?

 

[isayyo2]

For the AH 56 Cheyenne, these trials pretty much meant the program was dead. Lockheed had developed the Cheyenne to be a cross between a helicopter and airplane. The rigid rotor system using a gyro assist to tilt the whole assembly while the blades were fixed in pitch was done to allow for high speed and to use the rotor at high speed as a flight control to maneuver the helicopter, the stub wings providing enough lift at high speed to partially unload the rotor from generating lift.
All that meant the Cheyenne couldn't hover in ground effect almost at all. NOE flight was difficult or even in some tighter terrain, impossible to do. The flying above small arms ground fire and using diving attacks with rockets and guns as the Army did in Vietnam, was a sure way to be shot down against light AA cannon and SAM missiles.

Unless I missed something was the Cheyenne not designed from the outset with TOW in mind, with the AAFSS program aimed for Western Europe? It had an incredibly advanced (and very complex) rotating sighting system that allowed for day and night TOW operations in any weather condition. If you have a free hour, I would read what one use on our forum has written about the potential use of Cheyenne's in Europe: AH-56 Cheyenne and derivatives Post #334

 

[T. A. Gardner]

I'm of the opinion that even if it wasn't suitable for long-term Army needs, the Bell 309 Kingcobra would have been preferable for new production than plain AH-1S variants. There is still a lot of commonality between AH-1Gs converted into AH-1Ses and the Kingcobra, but the latter offered a real night attack capability on top of generally improved performance in other parameters.

Considering we are talking about potentially some 609 airframes (production AH-1S series, Japanese AH-1 and production AH-1W), I think it could easily be financially justified. Moreso since the Apache didn't enter service until about 1984. That's excluding the AH-1T which itself reused many components of the Kingcobra.

Which bring us back (once again) to the Cheyenne, CAS USAF vs Army turf war of the 60's.
Which led to
- AH-56 Cheyenne
- AH-1 Cobra
- A-10
-YA-9
-Bell 309
- Sikorsky S-67
- YAH-63
- AH-64
- A-7F
-A-10B
-AF-16
All this because USAF was only sure about two things, related to CAS
- It can't be an helicopter
- We must piss the Army

Every single entry in that list was a fine flying machine (except the F-16 gun pod). And a lot of them ended wasted at great taxpayer dollar expense...

In which case Archibald, could your list also include the either the Fiat G.91/Northrop N-156F (F-5A)/Douglas A4D-2N?

Regards
Pioneer

In the field of helicopters, the problems with many of the advanced attack ones at the time was they started development and reached prototype status just as the Army found out that all the lessons they'd learned in Vietnam using helicopters were completely wrong for an environment where the likely opponent (eg., the Soviets) had lots of air defense systems.

The Ansbach trials held in Germany using US AH-1's equipped with just 2.75" FFAR rockets and guns proved that the tactics the Army used in Vietnam were suicidal against Soviet air defenses. The helicopters had to adopt totally new tactics, and needed new weapons like the TOW missile.

For the AH 56 Cheyenne, these trials pretty much meant the program was dead. Lockheed had developed the Cheyenne to be a cross between a helicopter and airplane. The rigid rotor system using a gyro assist to tilt the whole assembly while the blades were fixed in pitch was done to allow for high speed and to use the rotor at high speed as a flight control to maneuver the helicopter, the stub wings providing enough lift at high speed to partially unload the rotor from generating lift.
All that meant the Cheyenne couldn't hover in ground effect almost at all. NOE flight was difficult or even in some tighter terrain, impossible to do. The flying above small arms ground fire and using diving attacks with rockets and guns as the Army did in Vietnam, was a sure way to be shot down against light AA cannon and SAM missiles.

That's pretty much why it didn't proceed any further in development, the entire design would have had to been redesigned to make it work.

The YAH-63 proved inferior to the YAH-64 that became the Apache. That Bell's AH-1 has proven viable in combat almost to today says a lot about the original quality of that design.

What about the 309 as a potential bridge? I have heard the two-bladed rotor was questionable on this one but was the aircraft just too new to justify starting production in the interim to AH-64?

I'd say the 309 was more of an improved AH-1 and the Army saw it as not better enough. This would be a case of why spend on better when we can wait a year or two and get something that is really much better and more capable of further development?

The Army had the advantage at the time of not being engaged in a war, so that kind of makes sense.