counterrotating propellers

The Inspector · **Posted:** Fri Jan 11, 2008 4:43 am

Why is it that the British, the French, and the Russians all seemed to be able to produce so many aircraft that sucessfully used counterrotating props. Yet every U.S. manufacturer who tried them failed miserably and gave up?

Anowreck · **Joined:** Sun Dec 16, 2007 5:06 pm **Posts:** 28

The Inspector wrote:

Why is it that the British, the French, and the Russians all seemed to be able to produce so many aircraft that sucessfully used counterrotating props. Yet every U.S. manufacturer who tried them failed miserably and gave up?

Uncomfortable associations with Lockheed Salmon and Convair Pogo perhaps? :lol:

RickH · **Posted:** Fri Jan 11, 2008 8:48 am

Don't forget the problems that Northrop had on the XB-35 contra prop gearboxes

Jesse C. · **Posted:** Fri Jan 11, 2008 10:24 am

Don't forget Hughes' XF-11. The props where the cause of his crash.

I think with the big push towards jets the U.S. may have just hung up the contra prop idea.

bdk · **Joined:** Sun May 02, 2004 1:16 am **Posts:** 11330

The Inspector wrote:

Why is it that the British, the French, and the Russians all seemed to be able to produce so many aircraft that sucessfully used counterrotating props. Yet every U.S. manufacturer who tried them failed miserably and gave up?

How many are still being built around the world? Maybe the US discovered they weren't worth the weight, cost and complexity much sooner?

CAPFlyer · **Posted:** Fri Jan 11, 2008 12:44 pm

I don't think any of the above had truely working designs though. The Tu-95 uses what is essentially 2 engines attached one behind the other and driving 2 separate props so there is no complicated gearbox as in other installations attempted in the US in Britain. The Griffon gearbox was always a source of technical concern and was subject to frequent and time-consuming inspections. The Tu-95's systems rely heavily on Titanium (which is abundant in Russian designs) to take the stresses and heat of operation, so they are a bit more robust, but it has still been a source of mechanical reliability issues throughout it's service life.

famvburg · **Joined:** Fri Oct 07, 2005 9:41 am **Posts:** 540

Technically, you're talking about contra-rotating props. Counter-rotating props were on the P-38, F-82 & some other a/c.

Anowreck wrote:

The Inspector wrote:

Why is it that the British, the French, and the Russians all seemed to be able to produce so many aircraft that sucessfully used counterrotating props. Yet every U.S. manufacturer who tried them failed miserably and gave up?

Uncomfortable associations with Lockheed Salmon and Convair Pogo perhaps? :lol:

lestweforget · **Posted:** Fri Jan 11, 2008 1:17 pm

Don't know much about the workings of contra-rotating props

, but I would have loved to see this going into production... :rock:

Tigercat · **Joined:** Mon Jun 20, 2005 11:54 am **Posts:** 288

Jesse C. wrote:

Don't forget Hughes' XF-11. The props where the cause of his crash.

I was at the 1979 Reno Air Races and witnessed Steve Hinton's crash in the highly modified Mustang, The Red Baron. This aircraft sported a Rolls Royce Griffon engine with a contra rotating six blade propeller.

As I recall, the cause of the crash, which totally destroyed The Red Baron , was mechanical malfunction of the contra rotating prop.

Ted

Jet Mech · **Posted:** Fri Jan 11, 2008 4:18 pm

From the back of my gray matter, the main purpose of the counter rotating props were to offset the torque effect a single direction prop/s make in reguards to straight foward flight with neutral controls.

Some AC manufactors actuall cocked the rudder a little to offset the torque.

P-38's use one on each side spinning in opposite directions to reduce the problem (when both were running)

PeterA · **Posted:** Fri Jan 11, 2008 4:23 pm

Tigercat wrote:

As I recall, the cause of the crash, which totally destroyed The Red Baron , was mechanical malfunction of the contra rotating prop. Ted

..that same prop assembly that gave near on 40 years of service on the RAF's Shackletons. :wink:

PeterA

http://en.wikipedia.org/wiki/Avro_Shack ... al_history

Old SAR pilot · **Posted:** Fri Jan 11, 2008 6:15 pm

Mmmm, I think that was to overcome P-factor, as opposed to torque.

b29flteng · **Posted:** Fri Jan 11, 2008 7:46 pm

I suspect the reason behind the contra-rotating props was to use the abundent horse power with out too large of a prop diameter, in addition to the torque factor. The Griffon put out about 2,200 hp.?? with a ten foot, five blade prop?, and the B-29 had 2,200 hp. with a 16 foot 7 inch four blade prop. The Shack. had a six blade 10 foot? contra-prop. Just a guess...

Jerry O'Neill · **Posted:** Fri Jan 11, 2008 9:19 pm

Chance Vought built an experimental Corsair with Counter rotating props...but it sucked.
Jerry

bdk · **Joined:** Sun May 02, 2004 1:16 am **Posts:** 11330

Tigercat wrote:

As I recall, the cause of the crash, which totally destroyed The Red Baron , was mechanical malfunction of the contra rotating prop.

A loss of ENGINE oil pressure caused the blades to go flat. Drag was increased, descent was ensured. There was nothing wrong with the prop until the crash.

Quote:

With the record in hand the aircraft was prepared for Reno, '79. During the final Gold Race with Steve Hinton in second place the old nemesis of blower gear failure occurred. This time however things went from bad to worse to catastrophic. Broken pieces of gear jammed the pressure oil pump resulting in rapid engine failure due to a failed rod. Steve could not get the prop feathered resulting in the contra prop acting as a massive air brake. The ensuing crash landing in the desert resulted in a huge fireball and total destruction of the aircraft but miraculously, Steve came out of it alive albeit seriously injured. Thus the final chapter was written on an aircraft that never saw it's true potential realized.

http://www.lonnieortegaaviationart.com/ ... airra.html

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