South Africa companies developing the Ahrlac
While not directly related to our DoD pursuit of a "COIN" a/c capability, this fella looked interesting: http://online.wsj.com/article/SB1000...143821174.html
Quote:
Two South African companies are attempting to elbow their way into the global defense market with an unusual new aircraft developed on home soil.
Paramount Group and Aerosud Holdings Ltd. on Tuesday will unveil the Ahrlac, a compact plane that they say merges the capabilities of a drone, an attack helicopter and surveillance aircraft.
"There's nothing like it in the marketplace," says Paul Potgieter, managing director of closely held Aerosud.
The Ahrlac—short for Advanced High Performance Reconnaissance Light Aircraft—aims to fill a niche left by less-versatile and more-expensive rivals. Most countries on the continent rely on modified cargo planes or turboprop fighters for surveillance work, but the Ahrlac is a multipurpose alternative that's marketed for perform military and civilian reconnaissance. It will cater to African governments involved in combat, peacekeeping and humanitarian work, he says.
http://si.wsj.net/public/resources/i...0926174210.jpg
More at the link.
Light Strike Aircraft - Question de Jour
Given that the US DoD is currently undergoing death by a thousand cuts and also given that the USAF has just announced a $355 million contract for the Afghan Air force Light Strike aircraft to the Super Tucano, (http://www.defense.gov/Contracts/Con...ontractID=4695) what are the chances that the USAF would cancel said contract if ISAF (NATO++++) passed around the hat to fund another aircraft of the same gendre, with adequate supply chain and training support? Let’s face it, this will probably blow out to 0.5billion, which is not an insubstantial amount in the current climate? I note also that Hawker-Beechcraft is challenging this contract as it's AT6 lost out, will that stall the procurement in anyway? ( http://www.flightglobal.com/news/art...-6-bid-365163/ )
an OA-X for effective and efficient CAS
Latest issue of Armed Forces Journal has an interesting article on CAS and logistics by COL Michael Pietrucha. [ http://armedforcesjournal.com/2012/02/8792325 ]
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A COIN proposal using a turbo prop in pusher configuration
The Stavatti proposal got my thinking cap going and I propose the aircraft The structure is graphite/kevlar/spectra composite. The armour is a spectra compressed UHMW/carbide composite rated for 50 cal at 200 m
The gun and 70mm rockets are laser targeted. Brimstone is fire and forget. Pars 3 LR can target both tanks and helos. Maverick is for targeting fortified positions, bridges and other targets requiring the larger warhead.
The regimen is to attack ground targets from 1500-5000 m, which is beyond the range of most ground fire.
The plane's cockpit, electrical and piping conduits, and engine are armoured. Fuel tanks are self sealing.
The plane uses the APS-30 recoil operated gun. Mags are in the fuselage, guns in the wing root fairings.
Engine drives a contra rotating prop 10 ft dia.
Wings have slats and two component fowler flaps. Airfoil is a NASA natural laminar flow airfoil as developed by Hitachi for their business jet offering. This combo develops a lift coefficient of 4 at 20 degrees angle of attack.
Plane is designed to take off at 60 knots at Max Gross and land at 40 knots, light.
Plane is meant to use 30X113 gun ammo, 70 mm rockets, as commonly used by helos, with the addition of Brimstone, Pars, and Maverick, to
permit use as a Front Line aircraft attached at brigade level, operating just behind the artillery positions.
shown in the attached Jpegs.
The stats are as follows (lb):
___________________Take Off__________Landing
Fuel------------------------------3,854.4____________771
Engine---PW 127G------------1150____________1150
Airframe_____________2000 ___________2000
Armour___________ ___2000 ____________2000
2 - ASP-30 suto cannon____228.80___________229
30mm 600 rds __________590.75___________ _59.
38 - 70mm AIPKWS _____1330______________ 0
6 - Brimstone missile______642______________0
2 - AIM 9X______________376 _____________0
6 - Pars 3 LR____________660______________0
2 - AGM 65 Maverick_____1090____________0
Pilot _________________ 200_____________200
Ejection Seat ___________120 _____________120
_____________________14,242__________ 6,526
PW 127G TurboProp HP 2920 MTOW 14250
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Aspects of the proposed COIN aircraft.
Quote:
Originally Posted by
carl
Goprisko:
I have a few questions.
Will the pusher propeller really work out? I can't think of a single aircraft design with a single pusher propeller that was truly successful except some sport designs. I read that an insurmountable disadvantage is that the prop has to operate in constantly disturbed air. Are the advantages of that configuration really worth it?
Will a laminar flow airfoil be work if the aircraft is going to be operating at low levels? In North America in the summer the leading edge will be fouled, horribly fouled, by smashed bugs, sometimes in just a few minutes.
Why just one seat, why not two? Perhaps an aircraft like this would be used for simply scouting out areas as much as anything else. Two pairs of eyes are a lot better for that.
All that being said, it would great from just an intellectual point of view to see something like this built. I get tired of reading about the latest delay in the F-35.
To improve airflow into the propellor please note that only the rudder lies ahead of it, the stabilizer is above it, and the wing is well ahead of it. Ever hear
of the B-36? Had 6 pusher propellors. Was the largest aircraft fully operational, the largest was the Spruce Goose.
The prop proposed is a contra-rotating one 10 ft in diameter with a 6 blade prop ahead of a 5 blade one, to minimize vibration.
Pusher propellors are actually more efficient than tractor propellors, and this one is operating behind a fuselage that is extremely fair and has minimal cross section.
The NASA natural laminar flow airfoil proposed was thoroughly investigated by Hitachi at speeds from 80-600 knots and at reynolds numbers from 3 million up. so yes it will operate effectively at low altitudes and at speeds between 40-500 knots.
Please also note that unlike the Stavatti Proposal, MTOW is held to no more than 5 X HP or 12,900 lbs. This provides the sort of performance inherent in the Thunder Mustang, with an engine that does not suffer from performance losses with altitude, the PW127G
One seat vs two, to keep MTOW low, with the pilot using a heads up display, in a fully automated airplane. Remember, that this cockpit is armoured against 50 cal so this pilot adds nearly 1500 lbs to MTOW when armour, ejection seat, oxygen system, and pilot are included.
Composite construction provides an extremely smooth, low drag skin, contributing greatly to performance.
The intended use of this aircraft is attack and destruction of ground targets found by the pilot, identified by a CAS observer elsewhere, or identified by ground forces. To do this job, this aircraft must have direct radio communication with friendly forces below, direct communication with whoever is supplying CAS, whether a L-19 bird dog, an officer attached to ground forces, or another aircraft, and direct communication with G-2(intelligence) at battalion or regimental level, (whomever this plane is attached to.
To minimize friendly fire incidents, this aircraft uses a combination of high definition RADAR and laser target designation, virtually identical to that used by attack helos.
However, the maintenance effort necessary to keep this aircraft operating is a fraction of that needed to maintain a helo,
Please also note that low level operations, in helos are no longer performed due to the prohibitive amount of maintenance necessary to repair ground fire, and airframe damage, from evasive maneuvering.
To fulfill it's role, this aircraft is not part of the airforce. If a Marine Aircraft, it is attached to an expeditionary force commander, if an Army Aircraft, it is attached to Brigade or a Batallion Commander, and those commanders organize logistics for it, prepare bases for it, and provide ground personnel to service and arm it.
The airforce provides air supremacy via aircraft such as the F-16/F15 at altitudes above 10,000 ft..
The airforce conducts strategic bombing campaigns against infrastructure, behind enemy lines, it no longer conducts bombing runs at the tactical level.
This change will incorporate the lessons learned from the WWII performance of the RAF in France following the Normandy Invasion.
Like the USAF, the RAF focused development on air superiority aircraft, and refused to support the design and implementation of a purpose built ground attack aircraft.
In counterpoint, the US Army Aircorps produced several competing ground attack designs, the most successful of which was the P-47 Thunderbolt, and it was the US Army which broke out first from the Normandy Beach head, despite inferior tanks, and less field experience fighting the Germans.
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3 Attachment(s)
Douglas XP-42 vs Proposal
Please compare the Douglas XP-42 to the proposal. Note several important
differences, as follows:
1. The proposal's propellor circle lies above the bottom of the fuselage, while that of the XP-42 extends 20% below the bottom of the fuselage.
2. The propellor of the proposal is much closer to the trailing edge of the
wing than that in the XP-42/
3. The distance between the aft landing gear and the propellor is much shorter in the proposal than in the XP-42.
4. The departure angle from the main gear to the prop is much greater in the proposal than in either the Stavatti SM-27 or the XP*42, 20 degrees in
fact, to permit landings at high angles of attack
5. The ventral rudder is fixed, for yaw stability only, and is there to protect the prop in the event of high angle of incidence landings.
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The SM-28 COIN proposal...`
Further enquiry into the aerodynamics of fighter aircraft brings up significant changes needed.
1. the Ogive nose shown, can and should be shortened, as it is a supersonic nose, and this aircraft will not exceed 0.7 Mach.
2. Work at Northrop on the F-20 program showed that the nose should be
elliptical with the major(long), axis being horizontal. to improve directional stability and reduce the size of vertical stabilizer needed.
3. The SAAB Viggen showed that the canard eliminated down forces from the horizontal stabilizer, improving lift at all speeds by 10%, so the proposal should have the rear stab deleted to minimize drag.
4. Work on various projects has shown that roll control can be effected by using the rudder and canard in concert, provided the Canard is "flying" that is fully rotatable, and provided the two sides can be rotated together in the same direction, or in opposite directions, as directed by the flight comnputer. This means the ailerons can be dispensed with, infavor of spoilers, and the entire leading edge of the wing given over to a slot, and the entire trailing edge given over to fowler two component flaps. This would greatly improve short field performance.
5. The gun placement shown, is a vast improvement over that on the A-10, given a much simpler mechanism, a rate of fire nearly equal that of the M230 chain gun, due to no spin up time, and mounting of two cannon means 1 second bursts of 16 rounds, vs the A-10's 30. Gun placement so the magazine is on the centerline, above the wing, means improved protection from ground fire, no CG changes consequential to gun use, and simplified reloading.
6. The dorsal inlet for the PW 126 G eliminates FOD and was proved on the UK test aircraft nearly 50 years ago.
7. A nearly 6' long landing gear leg on all gear provides improved ground clearance to enable rough field operations, and the wider stance of the revised main gear placement, provides great cross wind handling during landings. This coupled with a low landing speed of 40 knots empty, means cross runway landings, similar to those routinely performed by twin otters, will be the norm, and thus cross wind landings are un-necessary.
8. Carriage of rockets,missiles, and bombs externally, means simplified armouring, simplified launching of ordinance.
9. Location of external stores hardpoints so as to eliminate CG changes during release of weapons, simplifies design of the rudder and canard, eliminates yaw due to firing, and reduces pilot workload.
10. I am seriously looking into changing the rudder into two rudders canted 40 degrees, to reduce RADAR signature, improve roll control using the rudder, and reduce drag, via elimination of the aft norizontal stabilizer.
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