Homebuild Cruise missiles

Some great posts chaps. Interesting and I guess sad story about the guy in NZ, I remember that now although it wasn't in my mind for this post.


Re ground-hugging.... why? We all know the conventional logic but if your devise is cheap, why not fly it at a convenient height above basic AAA (say 3,000m or 4,000m depending on the enemy's equipment). That'd mean that if they wanted to shoot it down they'd have to use up a SAM, which'd probably cost more than the cruise missile. Combine that with a saturation attack...


Pulse jets seem a definite possibility, but what about piston engines? Think a UAV like airframe but on a one-way pre-programmed flight?

Here's an evolved idea:

* Big enough to fly at 4,200m but small enough to be launched from a UAV catapult.

* Piston engine for fuel efficiency but not speed (80-100kts)

* Drop tanks for extended range (for cheapness, two types of wing would be produced - if drop tanks aren't needed then wing would not have necessary drop controls, fuel shut-off valves etc). Also, smaller fuel pump could be fitted maybe).

* To attack, it sheds the wings and dives nearly vertically on the target, reaching terminal velocity. Might need to redesign tail to prevent damage when wing is shed. Also, might need all-moving tail fins.

* Optical recognition software to locate and hit target. Uses commercial off-the-shelf civilian technology. Solid-state memory ("Flash drives") etc. Avionics would approximate a cheap laptop computer without monitor or keyboard.

(Click for full view)


[edit on 10-3-2008 by planeman]

reply to post by planeman


you could use a pulse jet, but you would either have to 2 stage it with a small solid fuel rocket or launch it from a moving platform (another plane?) as pulse jets only get going when you shove a helluva lot of O2 down them... or a combination piston/pulse jet?

the problem with pison engines is that they are expensive and complex and prone to failure! pulse jets are just a shaped tube with an igniter and an injector!

(i can make a jet engine with a couple of hundreds pounds of thrust with an old turbo charger, 2 tin cans, a big old spark plug and a HT coil... thats quite scary isn't it!)

I'm pretty sure it would be possible to build a turbine powered cruise missile or UAV with significant range & tactically useful speed range & payload using COTS technology marketed to R/C & electronics hobbyists.

Nothing remotely classified about any of it.

Here is a good place to start shopping for turbines. A wide variety of small, lightweight camera systems can be found here.

Really, a determined and clever team could do it fairly easily.

Frankly I am surprised we do not see more guerrilla attacks using RPV's already.

I guess because accuracy tends not to be a major concern, and the technical abilities of these groups tend to be limited, unguided rockets & mortars are in much wider use.

Interesting. Mind you those jets are pretty pricey - about $15000 per throw. Here's a size and specs comp with the Tomahawk's jet. Obviously the Cheapohawk wouldn't require to match the Tomahawk's performance, but it's a rough gauge. Thrust to weight ratio is another problem.



Still, it's worth exploring further.

I think air launched would be a good option.
You won't have the problem of trying to find a launch site within range.
Removes the problem of the extra power needed for launch.
If it was to fly at 4,200m it would use a lot of fuel to get up there.

Although it would need to be more compact say with fold out wings, as you would want your launching aircraft to be able to carry a good amout

Originally posted by solidshot
Wasn't there a bloke in Australia/New Zealand a few years back that claimed he was able to build a cruise missile for only a few hundred dollars? iirc he was forced to hand over the plans ect after the US government pressured his government to stop him?

www.theage.com.au...

That's right - I thinking about this just the other week... When I saw this thread I hoped it would be a follow up on his project. Although I vaguely remember a younger Ozzy bloke in a video, same project?

Any one suggested Hydrogen Peroxide as a propulsion method yet?

It would be impossible to build a cruise missile with a 500km range for $10k. Anti tank missiles with range of 10km cost more than that.

Planeman, here is a a little something i drew up:

My solution is a pusher propeller missile, built around 200hp '08 Suzuki Hayabusa Engine. Given the engines maximum consumption of 50l/h. 100l Fuel tank would give a range of roughly 800km at 400km/h cruising speed.

Missiles frame would weight roughly 170kg, engine and fuel 180kg, Electronics and sensors 10kg, payload 200kg.

Naviagation and control are easily achievable, with combination of a GPS-Pod and a PC. Major parts of the software can be ripped from commercial autopilot solutions. GPS-Map loop can be used to avoid terrain collisions with

acceptable accuracy.

As a 400km/h cruise missile would be piece meal to any half decent AAA, it's designed as a two-stage missile, with secondary stage being high subsonic rocket motor and payloand, controlled by the canards that separate from the the wing/engine section along with the payload and rocket motor. Second stage shoots up high and gathers speed with a near vertical dive to get through trashfire. Rocket phase will only have about 7km range.

Cost would be:
5000$ Engine
1500$ Electronics (Computer, GPS pod, CCD camera)
1000$ Rocket Motor
1000$ Misc Parts
1500$ Frame (glassfiber over Garbonfibre frame)
-----------------
10000$

reply to post by northwolf


I notice you have no dimensions for this 'missile', see bussa engine below..



now granted you could probably loose a lot of the gear box - but is a 4-stroke motorcycle engine really the best option here (and would you really want to waste such a sweet motor?).... I think not.

1. It's huge - this thing would be some sort of small aeroplane, 1300cc you could have a light aircraft you could commute with every day!

2. Far to much power... you would simply waste all the power (and it's a big un-aerodynamic expensive piece)

3. What's wrong with a much smaller 2-stroke?

4. Waste a sweet engine like that and I will cry

But i like 4-stroke engines and you need around 200hp in order to get a decent performance. By comparison to regular aircraft, as this is closer to an Extra 300 than tomahawk... But you could do with a smaller engine and a turbocharger. And as it would only have to work for two hours or so.. you could use some serious pressures to get the power. I just picked up the busa engine because it fitted the power range COTS. probably a 4-stroke 600cc from CBR and turbo would be just as good. But i don't know how well 2-stroke engines do in manouvering aircraft?

Dimensions 4m and frame diameter is 55cm. Wing span isn't on scale (didn't calculate the needed size)

Ps. At least i didn't use a Ducati engine here... THAT would have been a waste

Pps. It's good to get feedback keep it coming.

[edit on 11-3-2008 by northwolf]

reply to post by northwolf


Yes please leave anything Italian alone (you butcher of motorcycles you)

I would of thought 2-stroke cos of the simple nature, the high(er) power to weight ratio, and the reliability at constant high revs - so long as the motor is running good 2-strokes love to rev high.. 4-strokes on the other hand have cams and in the bussa's case injectors and so on.

One other thing is that this 'missile' or any other aircraft makes use of all the 3 dimensions - much more than a motorcycle... example the aircraft makes a steep turn, or even inverts the fuel in the tank will slosh - you may see this and have the electrics and airframe to correct the aircraft (hey you could have digital cameras streamed over GSM networks or something) problem is your fuel is subject to gravity and that may be a problem... you don't want to carry more fuel than necessary cos of weight - so your tank is gonna be half empty sooner (no matter the size of the tank), mind you the injected engine would have an advantage over a carburettor one on that issue.

[edit on 11/3/2008 by Now_Then]

You can minimize the problems in fueltanks by designing the into smaller compartments wiht sloshplates etc. Injection systems for fine inverted. But as i said i'm more familiar with 4-stroke systems so that's the rationale behind my preference.

But you could use the GSM datalink and an additional camera to get a verification of weapon effect from the tail section (you could get it to glide separately towards target) after the payload section has hit its target.

reply to post by northwolf


Regarding the GSM - sure that extra tail piece is a nice idea, the GSM link sorta comes from a back of the mind idea I have played with for years. I've always kinda wanted to fit a large robust R/C air craft with more complex avionics.

Basically I would use a laptop main board / processor / HDD etc for the processing power. As anyone would know there are all sorts of USB products (namely GPS and cameras)... What I really wanted was something that would take off on R/C and then basically operate out of sight from a laptop - constantly feeding back the required. Also I wanted a backup so that if contact was lost, a route would automatically bring the thing back to R/C range for a landing. Thing is I was thinking about this back in 2001 when I worked for a mobile phone company and HSDC was being rolled out (a tech that was doomed ) so in the 7 years they have basically done all that and made it off the shelf

Of course you can't just experiment in built up areas... Might hurt a kitten or some such. (Also funds are quite important )

The quality o the discussion is excellent, thanks

Let's all work together discussing and fleshing out different concepts to the point that we can evaluate their merits. I think we should frame this as a super-cheap cruise missile for use by US forces and their allies, particularly countries that are poor and face a less sophisticated aggressor.

I'll leave the motorbike engined idea with you guys, and see if I can't flesh out the feasibility of using the commercial micro-jet. My gut feeling after reading the posts here is that pulse jets are the obvious winner, but microjets present an interesting idea.

Norwolf, great minds think alike. I too am thinking along the lines of separating inconvenient parts (engine, wings etc) for final phase. I'm guessing that if you dive from 4,000m+ (13,000ft) it'll easily reach terminal velocity and be very hard for AAA to deal with. Of course, the sophistication of the enemy is a factor, but the air defense systems to shoot it down probably cost more than the missile so a win anyway.

The is a precedence for the separation idea, the top secret (at the time) Amber-1 project, which shed its wings to dive on the target. It ultimately led to the Predator UAV.




Going back to the Microjets, the same company that we've been looking at has its off-the-shelf microjets used in the following UAVs. From these we can maybe gauge performance etc.

BAE Systems Eclipse



Saab SARC



This gives you an idea of the size..



And my favourite, in terms of proving that these engines are credible for 'larger' aircraft, the Cri Cri

Noted French pilot Nicolas Charmont has installed 2 AMT Olympus
turbines in his Cri Cri together with AMT on-board automatic
start-up units and individual EDT's.
The Cri Cri weighs 170 Kg, and should have enhanced
performance withover 36 Kg of thrust available.
The Cri Cri has made his maiden flight in the weekeind of 7-8 March.
Top speed at this flight was 240 km/hour (150 mph). Flying with
only one engine the speed is still 160 km/hour (100mph).

More here, mostly model aircraft www.amtjets.com...




[edit on 11-3-2008 by planeman]

Oh my this is funny,
So many clusless people, that have no idea what it would take to build such a thing a a cruise missle. I is obvious by the replys so far there is not one person qualified in anyway, to even postulate on what it would take to acheive even the level of technology in an obsolete old cruise missle.

Originally posted by planeman

I like that....

Someone... mention no names suggested this...



Edit: Peace!

[edit on 11/3/2008 by Now_Then]

Originally posted by punkinworks
Oh my this is funny,
So many clusless people, that have no idea what it would take to build such a thing a a cruise missle. I is obvious by the replys so far there is not one person qualified in anyway, to even postulate on what it would take to acheive even the level of technology in an obsolete old cruise missle.

Sounds like a man win an opinion. Please chip in with an explanation of why cruise missiles could not be made cheaply. What's the absolute cheapest one could be made for?

As a frame of reference, a "Cruise missile" in this context would be a longer ranged weapon that 'flies' to its target (as opposed to a ballistic rocket), striking with relative accuracy, with no outside command once launched. The German V1 was probably the first such weapon, although expectations or accuracy are greater these days.

[edit on 11-3-2008 by planeman]

Ok, here's a basic layout for a Cheapohawk using the commercial AMT Titan micro-jet.

The image is close to scale.


The payload (blue, front) is a US Mk81 250lb bomb. By the time you lose the fins etc, it weighs just over 100kg and is about 1.6m long by 0.28m diameter.

Beneath the warhead are two cameras, one facing down for navigation and one facing forwards for terminal guidance.

The fuselage is square wit rounded edges except the nose and tail which are moulded into more aerodynamic shapes.

Range
Behind the payload is the fuel tank. Fuel would be regular kerosene. I've calculated that there'd be about 202 Liters (1.4m long, 0.39m wide and high. 95% used volume) which'd weigh abut 165kg. We know that the AMT Titan micro-jet burns 1.12kg of fuel per min at max power. So simple estimate of range:

Fuel would last 2.4hrs at max power. Thus if max power put you at 150km/hr (about 90mph), that'd equate to 368km. Say, for the sake of argument, that the missile could fly at an average speed of 250kt, that'd get you 615km.

If 75% power used 60% of the max fuel usage (off the cuff estimate), and got you to 120km/hr, then you'd have a range of 490km.



Weight
Components:
Payload: 105kg
Fuel: 168kg
Engine system: 4.5kg
Guess the rest: 25kg
Total: 300kg

Max Thrust: 40kg

Thrust to weight ratio: 0.13 (Tomahawk = 0.20)


Avionics (light blue), pumps, cooling etc would be at the rear of the airframe to compensate for the heavy payload forward.


The most obvious problems with this layout/powerplant is lack of launch/climb power, and probably centre of gravity issues as fuel is used.


Unit cost (100 built)
Micro-jet: $15,000
Payload (Mk 81): $5,000 (guess, cheap inports )
Airframe inc construction: $2,000
Software/aerodynamics research: $5,000 ($500,000/100 units)
Hardware: $1,000
Total: $28,000 (about half that of a JDAM. A Tomahawk costs between $600k and $1m depending which source you quote).

[edit on 11-3-2008 by planeman]

While I have followed this thread with great interest and noted some of the novel solutions, why not just modify a civilian airgraft?

A Cessna 172 has a range of about 800 miles and since safety is not a concern that could be extended with additional fuel. Autonamous control with GPS correction?

The a/c can be purchased used for as low as $29000 US

www.aso.com...

All you would need to do is automate the avionics and then viola you have your cruise missile

Edit to add:

A Cessna 150 can be had for less than 16000 US
www.aso.com...

Its just over half the range of the 172, but you could extend that with more fuel tanks


[edit on 3/12/08 by FredT]