It's been a long time since I've posted regularly. The answer is partially revealed here tonight.
For the last few years I've been writing articles for a variety of in-house magazines attached to the Northrop Grumman Engineering Department. Starting sporadically with "The Leading Edge," a traditional hard-copy magazine, to "VelocitE," a combination pdf/on-line journal, to the current "Airspace" and its pure, on-line format, I've been gradually writing more and more current and historically-themed pieces.
Earlier this year I was given my own column. While exciting, it's been very time consuming as there is a lot of research involved in some of the articles. Also I've now gone on a 9/80 schedule at work, making for longer days and tougher commutes. Since I do all of my writing on my own time at home, something had to give. Sadly, that included blogging (I think eBay stock dropped as a result, too).
While I've gotten a lot of good response to my articles, I couldn't share them with anyone outside of the company. Fortunately, Diane Hensley, my very generous editor, granted me permission to reprint these on my blog.
However, before I could do so, I had to get them cleared for public release through the Northrop Grumman system. That has been an interesting experience and something of an eye-opener. In today's environment, everyone is being extra cautious. It's understandable, but very frustrating at times.
I now have several articles that have cleared the process - photos included - with several more in the queue. I hope now that I will be able to post more regularly and you can see the results of my work. I hope you enjoy them.
This article was published in Airspace vol. 2 no. 7, May 2011. It is reprinted here with permission and has approved for release case number 12-1465.
Northrop’s TAB for All Seasons
By Tony Chong
Perhaps one of the most unusual designs proposed by the
heritage Northrop Corporation was the Truck, Airplane, Boat (TAB) Vericraft
triphibian, an ungainly looking vehicle that attempted to be the all-in-one answer
to the U.S. Army’s looming tactical needs.
TAB was developed in the mid-1960s in an attempt to secure
participation in an Advanced Research Projects Agency (ARPA) program called
Project AGILE. One of the issues under
investigation was the problem of mobility and logistical supply to remote bases
and outposts in inaccessible environments.
With the U.S.
increasingly involved in the Vietnam
conflict this was a major concern for military planners.
Northrop envisioned a rugged, easy to build, low-cost aircraft
that had the ability to operate effectively not just in the air, but on the
water and on land as well. While
primarily designed for the short-range utility cargo mission, it was to be easily
adaptable for use as a troop transport, weapons carrier, mobile command post or
medical evacuation vehicle.
The proposed craft featured a rectangular box of a fuselage
outfitted with a catamaran hull, retractable wheels and rotatable wings and
tail. Twin Pratt & Whitney PT6-B15
turboprop engines, mounted in a single pod nacelle, provided power to a 7.5
foot shrouded propeller. Engineered with
a constant-chord wing with a span of 60 feet, the TAB was to be 40 feet long,
with a folded wing width of 9.5 feet and a height of 13.5 feet. The cargo compartment was to be 6 feet high,
6 feet wide and 15 feet long. Gross
weight, complete with up to 4,000 lbs of cargo, was projected at 12,000 lbs.
Conversion to any operational mode was anticipated to take
approximately 10 minutes. Additionally, all
mode conversions could be done onboard the TAB during water operations. The vehicle was also scaled to fit into the
cargo hold of a Lockheed C-130 Hercules transport for long, overseas
deployments.
Northrop expended considerable time and effort in this
design. A multi-volume proposal brochure
was developed that included cost and operations comparisons to other proposed
Army vehicles, including the fixed-wing de Havilland of Canada CV-2 (later C-7)
Caribou and the rotary-wing Boeing-Vertol CH-47 Chinook and Bell UH-1 Iroquois
(Huey).
Performance was projected to be modest. The 130 mph air speed would be slightly
faster than the Huey but much slower than the Caribou or Chinook. Truck speed would top out at 50 mph. Ironically the boat mode would provide the
best performance with calm water speeds up to 35 kts.
A detailed scale model was built toward this effort, along
with a larger scale radio controlled model of the basic TAB design. Interestingly enough, no formal N-number was
attached to the program. While a Preliminary
Design (PD) number was likely given to the TAB, its identity has proved elusive
thus far.
In any event, the program did not go forward. ARPA declined to offer funding, perhaps in
part because the newly implemented 1966 agreement between the Army and U.S. Air
Force mandated that the Army give up all fixed-wing tactical airlift
capabilities in exchange for unrestricted development and acquisition of
rotary-wing assets. TAB’s primary
customer was now obliged to go with the UH-1 and CH-47. The end result was the coming of age of the helicopter-borne
air-mobile Army during combat operations in the Vietnam War.
Kristi Harding contributed to this article.
Photo Captions
- 100_0001_rlw: The TAB proposal brochure included this artist’s
conception of the vehicle in a scenario that showcased all three modes. Boat operations could take place on
rivers, estuaries, coastal areas, lakes and, revealingly, rice
paddies. Clearly Southeast Asian
environments were in mind. Image credit: Tony Chong collection
-
img662: This 3-view shows
the basic dimensions of the vehicle.
Note the split inlet on the nacelle for the twin P&W PT6-B15
turboprop engines. As a point of
reference, Northrop Grumman’s new X-47B UCAS-D is a couple of feet greater
in span and about a foot shorter in length than the proposed TAB. Image
credit: Tony Chong collection
- img665w: All three modes of transportation
are shown in this image. The stowed
wings would have shielded the shrouded prop, possibly dampening the noise for
bystanders. Image credit: Tony Chong collection
- img666w: The wing and tail folding operations
appear to be simple and straightforward, a plus for use by draftees in
rough conditions. Image credit: Tony Chong collection
- img675w: This detailed view, with
cross-sections, shows the catamaran hull design of the TAB. Image credit: Tony Chong collection
- img676w: The cockpit
would have been a fairly basic affair.
Instrumentation was only installed on the “driver’s” side even
though a second wheel was provided for the right seat. Image
credit: Tony Chong collection
- img667w:
TAB was designed to fit inside the Lockheed C-130 Hercules,
albeit rather snuggly. Note the Hercules
outline is of the early C-130A “Roman-nose” configuration. Image
credit: Tony Chong collection
- img670w: The projected aircraft performance
specs were very modest compared to other fixed wing aircraft, and even to
some helicopters. Obviously the
selling point was the versatility of the land and water options. Image
credit: Tony Chong collection
- img673w: Projected truck performance was
better, despite a top speed of only 50 mph and the ungainly addition of
large exposed surfaces from the stowed wings. One wonders how vehicle mobility would
have been affected by this, much less their susceptibility to road damage
and small arms fire. Image credit: Tony Chong
- img671w:
Water performance would be rather good, all things considered,
especially in speed. Note the sea
state operations/survivability figures.
Image credit: Tony Chong
collection
- Northrop TAB bw: Old Polaroid photos found in the
Display Model Shop archives show a rather nicely detailed scale model of
the TAB in profile with cargo ramp down.
The angle of the nacelle and shroud is more pronounced in the model
than in the 3-view, suggesting a different design iteration. Photo
credit: Northrop Grumman Display Model Shop
- Northrop TAB
cw: Another Polaroid showing a
high-angle view of TAB. The size of
the model is apparent when seen with the tabletop. Photo
credit: Northrop Grumman Display Model Shop
- TAB model lf frt: This
appears to be a studio shot of the TAB model with the wings and tail
folded into the stowed position.
The shrouded propeller is effectively shielded by the wings. They also appear to channel airflow to
the prop. Ground and water
operations would seem to be similar to Airboat vehicles. Since TAB was supposed to be able to
handle 45% longitudinal slopes on a hard surface, propulsion via prop would’ve
been interesting to see in those conditions. Photo
credit: Tony Chong collection
- TAB model lf rr: The TAB cargo bay was designed to hold either a standard Jeep, Army Mule, M-102 105mm Howitzer
or other like equipment. The model shows
two such payload options. Photo credit: Tony Chong collection
- Northrop
RC cw: Northrop authorized a
Radio Control (RC) model for concept testing. This is a shot of a straight-tail version under construction. Note the catamaran hull and wood body. Photo
credit: Northrop Grumman Display Model Shop
- 14060-104Aw: It is unclear
if only one RC model was made or if there were more than one. This image shows a variant with a
pronounced dihedral to the tail.
There are endplates to the tail as well and a tricycle-type landing
gear arrangement. The propeller
shroud also appears different in configuration, although that may be an
illusion due to the large side support structure of the model. Note the size compared to the
cameraman. Photo credit: Northrop Grumman
- 14063-104Bw: This photo shows the model taking
off for a flight. It is unknown how
many flight were made, or where. It
does not appear to be Hawthorne. One thought is that it might be the old Rancho Conejo
Airport, where the former
Northrop Ventura Division facility was located near the southern end of
the runway in Newbury Park,
CA. Photo
credit: Northrop Grumman