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I'm trying to find out why the designers placed the engines of the A-10 where they did. At first I thought it was to offset the weight of the gun system (CG's) but after reading that the gun wasn't even ready during the fly-off with the A-9 I guess that wouldn't have been a factor. Other than finding info that states the advantages of having the engines where they are I can't seem to find anything as to what led the designers to place them there.

Anyone know why?

TIA




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One of the desired design characteristics of the A-10 was extreme survivability in combat. During Vietnam many aircraft were lost due to fires in their engine bays which sometimes propagated to the other engine the aircraft may have had. The A-10 engines as you know sit in pods attached to the fuselage and can sustain fire damage and fire spreading to the other engine is greatly reduced if not eliminated.

<img src="http://img117.imageshack.us/img117/457/bgnrjsiiw81q1gc.jpg" border=0>

Gravity....its not just a good idea, its the law.

As was stated, that was one reason for separating the two and not placing them inside the fuselage. Placing them high, means less risk of ingesting FOD (Foreign Objects and Debris) making it not rely on an improved surface (runway/tarmac) for operations. It can be deployed closer front for quicker turn arounds. Being higher than the rear elevators, the elevators provide masking of the engines heat signature from below. I'm sure there are many more, but these are some of the more prevalent. I'll dig around some more after I get home from work if you need more.



Edited by - Growler67 on Oct 18 2006 19:13

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Just give me some ammo, a little water.....and some chips if you got 'em

Also, when a jet engine shells out and the engine is in the traditional spot, the fuel tanks are wrapped around the engine. What does all the pieces of the engine exploding hit? The fuel tanks. Eng fire + fuel tank = bad.

Also, I heard they had a brainstorming session during design and said, "OK, this thing isn't ugly enough yet, what else can we do?"
(For the record, I dont think its ugly at all, I swear, I think the Hog is THE best looking jet in the AF.)

What kind of answers are you lokkign for Hitler, I always thought the obvious well-known reasons (FO, survivability) were it. Where else could they put them?

Liberalism is a mental disorder.

Thanks for the replies, here’s what I’ve been able to find on the internet (not the most reliable source of info) since my original post


First the requirements as laid out in the A-X program for the design of the aircraft.

<BLOCKQUOTE id=quote><font size=1 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>
1 - Responsiveness
The pilot must be able to visually identify friend and foe and must be able to loiter above the ever-changing battlefield for extended periods of time so he can immediately respond when needed.

2 - Lethality
Destroy a wide range of enemy targets with accuracy and as little collateral damage as possible. Again with emphasis on the pilot being able to see his target so no gross errors would be made during delivery.

3 - Survivability
The ability to survive all sorts of damage and still make it back to home base.

4 - Simplicity
Maintenance and service times should be as short as possible, so the aircraft will spend most of its time in the air and not on the ground.

5 - Cost
Keep the cost as low as possible so the American Congress would allow the USAF a dedicated CAS plane. This because the people in Congress didn’t understand, and some still
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>


About the engine placement -

<BLOCKQUOTE id=quote><font size=1 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>There are many reasons for the location of the engines on the Warthog. First, as this aircraft was expected to be operated from forward air bases, often with semi-prepared substandard runways, there would be a high risk of FOD (Foreign Object Damage). The height of the engines significantly lowers the chance of sand or stones damaging the complex parts of the jet engines. This also means engines can remain running, allowing for shorter servicing and rearming turn-around time by ground crew. Servicing and rearming are further helped by wings closer to ground than for wing mounted engines. As mentioned above the position also reduces the IR signature which starts low anyway due to the high bypass ration of the engines. The bypass ration is 6:1 and so the engines are very quiet which aids against detection. Because of their high position, the engines are angled upward nine degrees to bring the combined thrust line closer to the aerodynamic center of the aircraft. This avoids trimming measures to counteract a nose down pitching moment if the engines were parallel to the fuselage. The engines, being particularly heavy components, require a high degree of strength in their support. Therefore forged engine-mounting nacelle frames are pin jointed to machined support beams.<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>


I guess I am looking for a definitive answer to if these where the actual reasons or merely an advantage discovered after the fact. IMHO, this seems as though it would have been a bold design concept considering the appearance of other military aircraft. For example, look at the A-10’s competitor, the YA-9A, whose engines are place inline with the fuselage. Additionally, I’m retracting my earlier statement about CG’s not being a possible factor. Seems as though the developers did know it would be installed after completion and you would need someway to counterbalance almost 4000 lbs (gun, feed, drum & full ammo) in the nose of the aircraft


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Edited by - Lil Hitler on Oct 19 2006 00:40

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For whatever reason they did I am glad they did because it made it a lot easier working on them standing up rather than squatting under them like on fighters in years back.

"GLAD TO HAVE BEEN THERE AND HAVE BEEN PROUD TO HAVE SERVERED"

Hitler, you have to remember once the decision was made, which BTW was made early in the design process, to use high bypass turbo fan engines, and the TF-34 in particular, the placement of this type of engine was driven by the fan size (37” if I remember correctly). BTW the A-9 used very low bypass turbo fans which allowed them to be placed in the fuselage. The engines main feature(s) which drove it’s use was fuel economy, heat signature (very low as you know), low sound, and the ability to take damage and keep operating. The only two places they could be placed was under/over the wing or on the fuselage somewhere. IIRC the gun balance (this could have been done with fuel) and the rest of the bennies of placing them on the aft fuselage, like FOD, was a extra reward(s) for placing them where they did.

Visit my A-10 website at
http://www.warthogpen.com

Dice, thanks that sounds more realistic than what I've been able to find.

Faugh ah Ballaugh -Clear The Way

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