Could the HP O/400 fly on one engine?

[Bob_Mackenzie]

Assuming it jettisoned its bombs?

Indeed I'm curious if any WW1 twin engined plane could fly with just the one engine?

Thanks

Bob

[Bob_Mackenzie]

Anone?

Is the lack of replies because the info is just not available, or is the answer just so obvious I shouldn't need to aks? (not obvious to me )

Cheers

Bob

[Epee]

Probably no info. It's an interesting question but one that I doubt has an easy answer. Given the limited number of o/400s, their combat conditions and their crews' limited survivability I doubt if there are many anecdotes of single engine landings unless such was performed in testing.

[Catfish]

Hello,

the Vickers Vimy could fly on one engine, Srs. John Alcock and Arthur Whitten-Brown had to demonstate this (if unintentionally) repeatedly when crossing the Atlantic for the first time, becasue of ice build-up at the carburettor intakes. No bombs, but fuel overload, and same engines like used in the war.
Don't know about the HP 0/400 though ..

Greetings,
Catfish

[Ransom E. Olds]

Catfish: Interesting to have the confirmation of a Great War twin flying on one engine. Would be nice to know what altitude an Eagle-powered Vimy could have maintained on one powerplant. Another candidate I had considered suggesting is the DeHavilland DH.10 Amiens--same Eagles and somewhat smaller overall, I think. Personally I can't image one lone Mercedes D.IVa could have pulled a Gotha or a Friedrichshafen through the air at any practical altitude. Maybe we'll hear from others. Ransom

[Chock]

I think most could probably fly on one engine, but I suspect it is doubtful they could have maintained altitude on one engine, probably managing a shallow dive to keep flying speed on, assisted by some power, rather than level flight. That's because it's not just a question of adequate thrust from the remaining powerplants, but also of whether the available power from the remaining engine(s) and the resultant asymmetric thrust can be countered with the rudder or ailerons, and whether crossover speeds will be manageable, all of which is doubtful given that control surfaces on most WW1-era aircraft tended to be fairly inadequate. Then of course there's another problem...

If we take for example the V-12 Liberty Engine, it typically had a dry weight of about 845lbs, more of course with the coolant and lubricants in it, and for that weight, it delivered - at best - 449 horsepower, which gives us a power to weight ratio of around 0.5 horsepower per pound of weight.

Naturally, air cooled engines of the same period would have a better power to weight ratio, but even so, it was not really until the mid 1920s, when Frederick Brant Rentschler was mooting the development of a much more powerful air-cooled radial engine by Wright (whom he was at the time the head of) that decent power to weight ratios were on the horizon. Even then, Wrights were not keen on pushing forward with developing Rentschler's proposal, and so he left them and teamed up with the Pratt and Whitney Machine Tool Company to get his idea for an air-cooled radial off the ground. This eventually turned out to be the Pratt and Whitney Wasp Radial, which had a one to one hp/pound ratio and of course powered the Boeing B-40 (Boeing's first airliner) which Boeing had built based on what they learned from studying the Fokker DVII, as well as the many US pursuit planes Boeing built for the US Army and Navy, which again were often glorified copies of the DVII.

Wrights of course realised Rentschler had been correct and went on to produce the rival Wright Cyclone air-cooled radial, and it was this and the Pratt and Whitney Wasp, and Hornet - a derivative of the Wasp - which made engine out flight on twins and multi-engined aircraft a realistic prospect.

Generally speaking, the P&W Wasp-powered Boeing 247D 14-passenger airliner is regarded as the first twin engined aircraft where losing an engine at service loads would not mean having to land immediately, and the 247 wasn't airborne until 1933, although I'm fairly certain that the earlier Ford Tri-motor could probably have had a decent stab at it too, and possibly some of Fokker and Junker's post WW1 airliner and mail aircraft types.

Al

[SCMc]

I believe that at least one of the reasons for the trimotor design was the difficulty of flying early two engine designs when one of the engines failed.

Steve

[Bob_Mackenzie]

Thanks Folks

Thats basically a "no" then

[Dan_San_Abbott]

Hi Bob:
I did a little arithmitic and here is what I arrived at.
1. The Take-off weight of a HP o/400 with 16 x 112 lb bombs with two 375 hp Rolls-Royce Eagle VIII engines rated at 1800 rpm = 13360lbs.
2. The wing loading is 13360/ 1820 square feet of wing area= 7.34 lbs/sq. Ft.
3. The power loading at take-off is 13360 / 2 x 375 hp= 17.81 lbs /hp.
4. The HP o/400, wing loading after bombs are dropped 13360-(16 x 112) =
13360-1792/ 1820 sq.ft. = 6.36 lb/sq.ft.
5. Power loading on one Eagle VIII= (13360 -1792) = 11568 /375= 30.84 lbs/hp. If the emermgency occured 1 hour after takeoff, the fuel consummed would have been 23 gallons x 2 x 7.0 pound /gal. = 23 x 14= 322 pounds.
adjusting the aircraft weight =11568-322=11246/375= 29.98 pounds/hp
6. HP o/100 fully loaded with 16 x 112 lb. bombs= 14022 pounds.
7. Hp o/100 minus bombs = 14022- (16 x 112)= 12230 pounds
8. HP o/100 wing loading minus bombs= 12230 / 1820=6.72 lbs/ft.sq.
9. HP o/100 power loading minus bombs with two engines= 12230 / 2 x 250=
12230/ 500=24.46 lbs/hp.
I think the HP o/400 could have flown on one engine with a slight glide and made it back to the aerodrome. But don't turn into the dead engine.
Blue skies Bob,
Dan-San

[LeicesterTiger]

During WW1, in the list of downed HP's I have in front of me, 20 are mentioned that had to force land specifically due to engine failure, so I don't think it would have been able to return to the aerodrome, especially as many were badly damaged/wrecked during the force landing (one into a forest) on the allied side of lines, or landed on the German side of the lines (again, usually badly damaged), which presumably wouldn't have been the first choice of the aircrew if it could be avoided. There was one case of engine failure on a HP on take off and it ended up running into trenches