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May 30, 2010, 10:45 AM
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awrightbrother's Avatar
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New Product

A10 Thunderbolt Big Bird from Wowplanes


I have always been particularly fascinated with the A10 Thunderbolt aka The Warthog. Around 4 years ago I had designed and kitted a 62" span model. That was before I got infected with the scale virus, so that was more of a fun scale design. It turned out to be an amazingly easy plane to fly, very manueverable and stable, and easy to land. Ever since then I have been wanting to do a scale version, and so here we are.

While at it, I thought it would be nice to scale up to an IMAA legal Big Bird size. For a jet, IMAA rules require that the sum of the wingspan and the length be at least 140". A wingspan of 73", yields a fuselage length of 67", which adds up to the magical 140". So that's where we are headed. At 73" span it is a 10.5% scale.

I could have made it bigger, but decided to stay with 73", a size that can easily be transported in most cars and yet be eligible to participate in Big Bird events. The other consideration was cost.

The attached pictures are of the prototype that I have just finished. The pink colored parts are going to be vacuum formed white plastic while the canopy will be clear plastic. The brown areas are shaped balsa blocks. The construction will be the usual foam/balsa/ply/composite, and I am hoping for a AUW of around 10 to 12 lbs.

Please take a look at the pictures. I would appreciate your input as to whether I have successfully captured the scale outlines. Also attached are pictures of the full scale plane. Any questions, please feel free to ask.

Fahim
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May 30, 2010, 11:17 AM
...design-build-fly-publish...
eye4wings's Avatar
Hi Fahim,
I think most of the features are captured pretty well.
The only one that screams is the nose - or should I call it the 'snout' as it's a Warthog? (You didn't do it that way to draw the flak did you?!)
The underside of the nose does not rise half as much as your model which makes the model look too benign! It's hard to make that out from the photos of the full size you posted, but the nose of your model looks more like a Gloster Meteor to me. I don't think the underside rises at all until forward of the cockpit, but I don't have drawings in front of me - not my favourite era!
Good luck with it anyway.
May 30, 2010, 12:57 PM
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awrightbrother's Avatar
Thread OP
Hi eye4wings,

I took the side view picture and superimposed it on the 3 view drawing. You are absolutely correct. The tip of the nose needs to be lower than it is and the curve less acute. This won't do, so back to the drawing board I go.

Thanks for picking this up. More minds are better than one proves to be right again!

Fahim

Quote:
Originally Posted by eye4wings
Hi Fahim,
I think most of the features are captured pretty well.
The only one that screams is the nose - or should I call it the 'snout' as it's a Warthog? (You didn't do it that way to draw the flak did you?!)
The underside of the nose does not rise half as much as your model which makes the model look too benign! It's hard to make that out from the photos of the full size you posted, but the nose of your model looks more like a Gloster Meteor to me. I don't think the underside rises at all until forward of the cockpit, but I don't have drawings in front of me - not my favourite era!
Good luck with it anyway.
May 30, 2010, 04:28 PM
Neophyte hacker
portablevcb's Avatar
Fahim,

This is a NICE one! I always am surprised at how slender the A10 fuse is.

Retracts? If so then a bunch of Sparky's ordnance need to be hanging!

charlie
May 31, 2010, 07:24 AM
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awrightbrother's Avatar
Thread OP
Charlie,

I have just the right retracts for this one. They can be optionally fitted with OLEO struts. That should look nice. http://www.wowplanes.com/product_inf...4ee20969d54b6a

Also have Sparky's weapon set.
http://www.wowplanes.com/product_inf...4ee20969d54b6a

The A10 does have a slender fuselage which makes for a low drag profile and should help a smoother flight. Pasted below is some info on the plane that would make for a easy to fly model. There is more at http://en.wikipedia.org/wiki/A-10_Thunderbolt_II

HISTORY
The A-10 Thunderbolt II is an American single-seat, twin-engine, straight-wing jet aircraft developed by Fairchild-Republic in the early 1970s. The A-10 was designed for a United States Air Force requirement to provide close air support (CAS) for ground forces by attacking tanks, armored vehicles, and other ground targets with a limited air interdiction capability. It is the first U.S. Air Force aircraft designed exclusively for close air support.
The A-10's official name comes from the Republic P-47 Thunderbolt of World War II, a fighter that was particularly effective at close air support. The A-10 is more commonly known by its nickname "Warthog" or simply "Hog". As a secondary mission, it provides airborne forward air control, guiding other aircraft against ground targets. The A-10 is expected to be replaced in 2028 or later.

DESIGN
The A-10 has superior maneuverability at low speeds and altitude, due to large wing area, high wing aspect ratio, and large ailerons. The large high aspect ratio wing also allows for short takeoffs and landings, permitting operations from primitive forward airfields near front lines. It typically flies at a relatively slow speed of 300 knots (560 km/h; 350 mph), which makes it a much better platform for the ground-attack role than fast fighter-bombers, which often have difficulty targeting small and slow-moving targets.

The ailerons are at the far ends of the wings to gain greater rolling moment, as with many aircraft, but there are two distinguishing features. First, the ailerons are larger than is typical, almost 50% of the chord, providing improved control even at slow speeds. The aileron is also split, making it a deceleron.

The sturdy landing gear, low-pressure tires and large, straight wings allow operation from short rough strips even with a heavy ordnance load, allowing the aircraft to operate from damaged airbases. If runways are damaged in an attack, the A-10 can operate from taxiways, or straight roadway sections, such as Germany's autobahn.

DURABILITY
The A-10 is exceptionally tough. The aircraft is designed to fly with one engine, one tail, one elevator and half a wing torn off.

The A-10's main landing gear is designed so that the wheels semi-protrude from their nacelles when the gear is retracted so as to make gear-up landings (belly landing) easier to control and less damaging to the aircraft's underside. A belly landing would be required in the case of a landing gear failure. Additionally, the landing gear are all hinged toward the rear of the aircraft, so if hydraulic power is lost the pilot can drop the gear and a combination of gravity and wind resistance will open and lock the gear in place.

There are several reasons for the unusual location of the A-10's General Electric TF34-GE-100 turbofan engines. First, the A-10 was expected to fly from forward air bases, often with semi-prepared substandard runways that presented a high risk of foreign object damage to the engines. The height of the engines lowers the chance that sand or stones will enter the inlet.




Quote:
Originally Posted by portablevcb
Fahim,

This is a NICE one! I always am surprised at how slender the A10 fuse is.

Retracts? If so then a bunch of Sparky's ordnance need to be hanging!

charlie
May 31, 2010, 07:34 AM
Neophyte hacker
portablevcb's Avatar
Thanks Fahim.

Cool setup.
Jun 01, 2010, 10:31 PM
Wowplanes.com
awrightbrother's Avatar
Thread OP
I re-did the nose and also added the airscoop behind the gun.

Now it looks much better.

Fahim
Jun 01, 2010, 11:29 PM
Flying electric since 1986
Mark Wolf's Avatar
Here's some inspiration for you, I took these last week at The Pima air museum and Davis-Monthan AFB:









Jun 02, 2010, 09:52 PM
Registered User
Looks good, signing on. Just the right size too if you ask me!

Keep the pics coming.

Cheers,
Dave
Jun 02, 2010, 10:19 PM
Neophyte hacker
portablevcb's Avatar
Mark,

Why didn't you take any pics of the flying ones at D-M? Or do they still get a bit nervous about taking pics on the AF base?

charlie
Jun 02, 2010, 10:32 PM
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awrightbrother's Avatar
Thread OP
Mark
Thanks for the pictures. Is this a graveyard for the A10s or are thyey operational machines?

Dave,
Stay tuned. I am waiting for the plastic parts to arrive and then I will start a detailed build with lots of pictures.

Fahim
Jun 03, 2010, 09:16 AM
Flying electric since 1986
Mark Wolf's Avatar
Quote:
Originally Posted by portablevcb
Mark,

Why didn't you take any pics of the flying ones at D-M? Or do they still get a bit nervous about taking pics on the AF base?

charlie
I was only on the base for the boneyard tour and never saw any of the active warthogs. There were some F-16's and C-130's overhead though.
Jun 03, 2010, 09:20 AM
Flying electric since 1986
Mark Wolf's Avatar
Quote:
Originally Posted by awrightbrother
Mark
Thanks for the pictures. Is this a graveyard for the A10s or are thyey operational machines?

Fahim
The A-10 fleet is undergoing a major wing renovation program to extend the service life of the plane. There were wingless Warthogs all over the place and a field full of wings in racks waiting to be rebuilt/modified.
Jun 03, 2010, 09:57 AM
Registered User
vonJaerschky's Avatar
Great project Fahim! The Warthog has awesome lines. Have you decided on a power system yet? 70mm or 90mm fans?
Jun 03, 2010, 11:31 AM
Wowplanes.com
awrightbrother's Avatar
Thread OP
Mark
Thanks for the heads up. I was getting worried that they were damaged in action.

vonJaerschky,
This size is just perfect for 90mm and the dusts are designed for that.

Of course the builder can modify the ducts for 70mm. The cost difference of the fan itself is not a whole lot these days. I prefer the 90 because they don't have to be driven as hard as the 70 to generate enough thrust. Less wear, tear, and heat to deal with on the motor, battery & ESC.

fahim


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