The A-4 Skyhawk

[Riggerrob]

Starting with one of the TA-4 might help, as it would give a larger canopy to start with or one of the Singaporean TA-4SU as they are actually longer.

If you kept the slats, one could go with manual slats to solve a heap of aerodynamic development issues.

Probably better to scale down the canopy on the US Navy's two-seater TA-4 trainer. That way the pilot's seat back could be closer to the centre-of-gravity, but you still have a large enough exit hatch.

On a replica, landing gear only has to be half as long ... as long as you skip carrying bombs, drop tanks, etc.

Also re-read some of the books about Ed Heineman to understand how he was able to build A-4
Skyhawks so much simpler and smaller and lighter than 1950s vintage competitors. A-4 was so small and landed so slow that it was one of the few US Navy jets that could operate from British, WW2-surplus aircraft carriers like those sold to Argentina, Australia, Brazil, Canada, India, etc. The Royal Canadian Navy trialed A-4s on HMCS Bonaventure, but never bought any as by then the RCN had decided to concentrate on anti-submarine warfare.

 

[Steve C]

I flew an A-4E Skyhawk today. It was a little over 56 inches long, had a wingspan of 37 inches, weighed about 5 lbs, and was powered by an 80mm ducted fan running on 24 volts. I purchased it in October 2017 and have hated it ever since. Yes, it's a neat-looking plane, but it does not fly well at all.

If it's a Freewing I set one up and it flies very well with no gyro. I even plugged up the cheater hole because it's not needed. Maybe your cg is off or your throws are too high. It has a very high roll rate that can be toned down by changing the linkage positions.

I don't see why a scaled down A-4 wouldn't work if you made it big enough to fit yourself and all of the components. If the airframe gets too small the canopy might look cartoonish though.

 

[Yellowhammer]

What engine are you guys think of for a scaled, or look-alike, A4?


BJC

The same one on the sub sonex. The T-100.

 

[Yellowhammer]

Probably better to scale down the canopy on the US Navy's two-seater TA-4 trainer. That way the pilot's seat back could be closer to the centre-of-gravity, but you still have a large enough exit hatch.

On a replica, landing gear only has to be half as long ... as long as you skip carrying bombs, drop tanks, etc.

Also re-read some of the books about Ed Heineman to understand how he was able to build A-4
Skyhawks so much simpler and smaller and lighter than 1950s vintage competitors. A-4 was so small and landed so slow that it was one of the few US Navy jets that could operate from British, WW2-surplus aircraft carriers like those sold to Argentina, Australia, Brazil, Canada, India, etc. The Royal Canadian Navy trialed A-4s on HMCS Bonaventure, but never bought any as by then the RCN had decided to concentrate on anti-submarine warfare.

I think the two seat version would be a better scale too. I really like the Trainer version!

 

[Yellowhammer]

Speaking of scaled war birds, I recall seeing a composite T-33 scaled down some. It really looked cool.
Has anybody seen that jet?

Thanks,
Yellowhammer

 

[Yellowhammer]

Fun discussion and great nostalgic video- Thanks. A question - It seems to me that the Viper Jet is a good example of the diminishing returns of down-scaling performance Jet Aircraft. Even their greatly improved MK2 version with stellar performance and (as reported) great overall handling is very tough to travel anywhere in due to the fuel burn rate verses capacity.

Even the comparatively meek Sonex Jet is limited to 200 miles per hop. Jets just gobble fuel so fast that even though we'd like there to be a baby fighter jet to build doesn't that scaling factor impact the reality to a point of severe impracticality?

Sure if I could afford a million bucks to spend on an plane and $20/minute to fly it the Viper or an A4 derivative would be a blast but I could get a 92' Shorts Tacono for $1M and have a usable range and 95% of the fun.. I know this is a builders forum so I'm sorry if my idea offends, just saying - jets are tough to scale.

Speaking of the Tucano, I am 99 percent sure my next kit is going to be the Tucano Replica by Flying Legends out of Sicily. I know the guys over there personally and they do a phenomenal job in all respects.
I think it is the best looking light sport prop plane on the market today. Hell, I even have all the drawings and build manuals for it already. Frank, the guy who owns the company, has really been a great friend and knows the passion I have for the Tucano R.

 

[Yellowhammer]

I would love to be the first to do it, but the odds are against it. So far, no one has successfully built a ducted fan powered replica. Even the Jet Hawk, which sold an untold number of plans sets, hasn't appeared at any fly-in that I've been to or read about. I thought the replica Russian fighter might make it, but it has been very quiet for a couple years. I'd better get back to my rolling DF test stand.

You an me both are fans of the ducted fan engine. Man I wish someone could make it work.

 

[Yellowhammer]

Probably better to scale down the canopy on the US Navy's two-seater TA-4 trainer. That way the pilot's seat back could be closer to the centre-of-gravity, but you still have a large enough exit hatch.

On a replica, landing gear only has to be half as long ... as long as you skip carrying bombs, drop tanks, etc.

Also re-read some of the books about Ed Heineman to understand how he was able to build A-4
Skyhawks so much simpler and smaller and lighter than 1950s vintage competitors. A-4 was so small and landed so slow that it was one of the few US Navy jets that could operate from British, WW2-surplus aircraft carriers like those sold to Argentina, Australia, Brazil, Canada, India, etc. The Royal Canadian Navy trialed A-4s on HMCS Bonaventure, but never bought any as by then the RCN had decided to concentrate on anti-submarine warfare.

I will do just that. I know the replica A-4 is just a dream but I love the A-4 and Ed Heinemann so much I have to read his books. Thanks for the inspiration.

 

[TarDevil]

Speaking of scaled war birds, I recall seeing a composite T-33 scaled down some. It really looked cool.
Has anybody seen that jet?

Thanks,
Yellowhammer

I remember that. Can't tell you a thing about it other that how envious I was.

 

[plncraze]

Can it burn diesel? LOL. And it is licensed in the "experimental" category isn't it?

 

[wktaylor]

Configuration closer to scale-down possibility?... T-45 Goshawk T-45 Goshawk

 

[wktaylor]

NOTE.
My 3rd most-favorite attack jet [was] the heavy-hauler A-7D [USAF] SLUF. Too bad the structure was made from the worst possible alloys 7075-T6, 7178-T6 and 7079-T6... fatigue cracking and corrosion doomed the jet to be a throw-away. However the Fort Worth TX heritage of the A-7 is evident in the F-16... IF you squint. New generation aluminum alloys and augmented turbofan engine [F-404, etc] would make the A7x jet eye-popping.
LTV A-7 Corsair II - Wikipedia
SLUF huggers... A-7 Corsair II Association, Inc.

PS: TA-7C [training 'tub', with enlarged dual-cockpits and canopy] might be something to consider... especially with a used J-85.

 

[Voidhawk9]

PS:

My 3rd most-favorite attack jet [was] the heavy-hauler A-7D [USAF] SLUF.
...F-404 [or newer] augmented turbofan engine would make the A7x jet eye-popping.

Would an F100 engine do?

 

[BJC]

However the Fort Worth TX heritage of the A-7 is evident in the F-16... IF you squint.

wk, I squinted as hard as I could, but still didn't see it.


BJC

 

[REVAN]

My 3rd most-favorite attack jet [was] the heavy-hauler A-7D [USAF] SLUF.

The 2-seat version was a nice looking plane. The A-7 was one of the few military fighter/attack planes that got better looking with the addition of a second seat. The F-5 was another in this category. IMO - The T-38 looks better than the F-5 Tiger.

 

[wktaylor]

BJC... bring the wing down to mid fuselage and move the inlet backwards.

Vh9...
The A-7D with an F404 engine mod would have been a superior upgrade with modest $$ investment and huge gains in climb performance, range and payload... to the basic jet.

OH... I suppose that You are talking about the YA-7F Strikefighter... Stretched, supersonic version of A-7 powered by a Pratt & Whitney F100-220 turbofan, optimized for interdiction role, but cancelled after only two were built. Vought YA-7F - Wikipedia

The project was canceled due to improved relations with former adversaries, lower defense budgets, and the Air National Guard, by then the principal US operator of the A-7, generally favoring the in-production F-16 Fighting Falcon

An odd aspect of significant modifications to old aircraft designs is that they can become 'so-much better', that they compete with the next/newer class of jet...

This happened with the F-5 single engine mod/upgrade that was re-designated the F-20A Tigershark [F404 engine]… and to the A-7D >> YA-7F and... with the F-4 test aircraft modified with F100-100.

Performance/payload improvements were astounding... but in the case of the F-20A and the YA-7F they were 'almost as good as the F-16'... and almost as expensive... and old technology. Hmmm.

In the case of the F-4, the F100 engines made it a kick-ass machine. The pilots discovered it had amazing maneuver/climb performance... and were constantly exceeding G limits and were 'beating-up' the relatively new test-airframe fatigue-cycles-wise. A new design F-4 airframe would have been required to keep-up with the engines. In this case the F-4 was still inferior to the newly designed F-15A/Bs in all respects.

 

[Vigilant1]

wk, I squinted as hard as I could, but still didn't see it.


BJC

I think you have to drink a lot, then squint.

They do both have the inlet and ducting under the main fuselage, which is unusual if not unique.

 

[Yellowhammer]

NOTE.
My 3rd most-favorite attack jet [was] the heavy-hauler A-7D [USAF] SLUF. Too bad the structure was made from the worst possible alloys 7075-T6, 7178-T6 and 7079-T6... fatigue cracking and corrosion doomed the jet to be a throw-away. However the Fort Worth TX heritage of the A-7 is evident in the F-16... IF you squint. New generation aluminum alloys and augmented turbofan engine [F-404, etc] would make the A7x jet eye-popping.
LTV A-7 Corsair II - Wikipedia
SLUF huggers... A-7 Corsair II Association, Inc.

PS: TA-7C [training 'tub', with enlarged dual-cockpits and canopy] might be something to consider... especially with a used J-85.

Man I love the A-7 too! What a machine. Last GUNFIGHTER!

 

[Yellowhammer]

The 2-seat version was a nice looking plane. The A-7 was one of the few military fighter/attack planes that got better looking with the addition of a second seat. The F-5 was another in this category. IMO - The T-38 looks better than the F-5 Tiger.

View attachment 107367

What a fighter plane should look like!

 

[Yellowhammer]

Would an F100 engine do?

**** sure would!