THE HISPANO-SUIZA V-8 718 & 1127c.i. CRANKSHAFT PROBLEMS

[m9a3r5i7o2n]

Quote from:
StephenLawson

Greetings M. L. Anderson;

May I say you have drawn a most impressive response in this thread with your comments. Thank you for the earlier reference to my comments. I look forward to your posts here.

My interest in the SPAD goes far back into my childhood when I was only about 10 years old in 1936. However my interest in the Hispano-Suiza only goes back to about 1991 the time I retired from Boeing as an inspector at the helicopter plant in Culver City California. At that time I was advised of the shake by another inspector who was a flyer and told me about the shake of the Hispano-Suiza engine. At that time it was very difficult to find out much about the Hispano-Suiza engine there being very little genuinely accurate and fully believable. I knew from the information I gathered in the following years that there was a lot more that seemed to be kept undercover to the problem. But your article really opened the door to the misinformation in the Caquot report. Which I will post sometime in the future. The part about the broken pipes is probably fully accurate but the missing information is most important.

This episode of the broken pipes reminds me of a Loan agreement I once signed in my youth that stated , “Time is of the essence of this contract.” and so it should have been with Hispano-Suiza, Caquot and the French authorities who were selling engines and the right to manufacture them to the British and Americans and also to their own manufacturers.

Yours, M.L. Anderson

[m9a3r5i7o2n]

Catfish
Observer
Hello,
I know a bit about engines, having restored a V6 Maserati engine and others, but this is not why I post here.
The German pilot Jentsch did fly a captured SPAD for trial and was very fond of it, saying "the engine is unbelievably steady and stable", at least respectively to the Albatros DII he flew at that time (he flew a Rumpler and a Pfalz monoplane before, but the Pfalz had a gnome rotary engine). I will have a look at the book whether it is written what kind of SPAD it exactly was.
He wrote it was no wonder the SPAD pilots always attacked from above (mentioning the brick-like behavior) and were able to aim and shoot exactly due to the smooth running engine. The SPAD seems not to have behaved shaky in any way, or a shaky engine did not have any impact on the rest of the plane, but I doubt it.
Greetings,
Catfish

My answer will apply to all the large Albatross 6 cylinder engines used by either side in WW-1.
Firstly one must remember that these engines had long strokes and the bores were keep to minimum to keep the engines short. The only really important Torsional vibration in these engines is the one that is usually not felt by the pilot but will destroy the engine over a period of time. The reason for the Lanchester Vibration Dampener.
Albatross, Rumpler, Pfalz Scout all had 6 cylinders. But if he was comparing it to a Rotary Radial engine I believe he would be very correct in his judgment as long as the Hispano-Suiza V-8 was in very good working order. However I am very prone to go more by engineering judgments than by individuals opinions of the shake. To really tell the shake one would have to fly one and then immediately fly the other aircraft.

I have often wondered what actual results would have resulted if a test of shooting at flying sleeves would have produced with a SPAD with a 220hp and an Albatross by the same pilot but to my knowledge it never happened. Some pilots seemed to have an uncanny ability to shoot on the fly with unbelieving accuracy.

Yours M.L. Anderson

[m9a3r5i7o2n]

For anyone who is interested in finding out more about the V-8 engines before 1923 and 180 degree crankshafts here are a few places I have written about (Right and Wrong) these types of crankshafts and their vibration/shake peculiarities.


Atlas F1 Bulletin Board - Flat-plane V-8 crankshafts

Atlas F1 Bulletin Board - Questions about Ferrari's road V8 engines...

Atlas F1 Bulletin Board - flat plane crank

M.L. Anderson

[m9a3r5i7o2n]

Copied from Glenn D. Angle’s book , “ ENGINE DYNAMICS AND CRANKSHAFT DESIGN”, PAGE #75, LOWER HALF OF PAGE.
1925,
Glenn D. Angle was in Charge of the Design of Airplane Engines for the United States Army Air Services and the Author of the book Airplane Encyclopedia.

Below is when he is writing about the 180 degree crank engine.

The vibrations resulting from the horizontal unbalanced inertia forces in the eight-cylinder 90-degree type engine are extremely unpleasant, and oftentimes prove destructive, especially to engine connections such as piping for fuel and oil. Service conditions have shown that there are practical limits to the size and speed of engines of this type. Experience might indicate that engines delivering about 250 h.p. at 1800 to 2000 r.p.m. approach the size in which the vibrations, due mainly to unbalanced inertia forces, are unfavorable to satisfactory airplane installation.M.L. Anderson

[Bletchley]

Thank you for posting that information

The Hispano-Suiza engines had an unusually short Time Between Overhaul of 50-60 hours (compared to a standard of 80-100 hrs for most other stationary engines by the end of the war), and I guess this would help to explain that. I have looked again at the two British reports that I have in digitised format (the 300 hp H-S and the 'Notes for squadrons in the field') and although they do not appear to include any direct references to vibration problems, there is certainly a great deal about lubrication problems. I can send them to you on a CD if you PM me with your postal address.

Many of the other stationary engines of this period seem to have had similar problems - the Rolls Royce Eagle had one at a certain rpm, and British reports on the Mercedes engines indicate that they also ran 'rough' at certain engine speeds.

Bletchley

[stork718]

This is a very interesting thread and I have just joined the forum having been put in touch by M L Anderson. Many thanks to him.

I have an aero engined car using the H3 1127ci Hispano and can atest to the vibration first hand. Using a 3 point sub chassis to prevent torsional crankcase loadings which is supported on shock-absorbing mounts, most of the vibrations are decoupled from the car and the occupants but there's no doubt that there are substantial out of balance forces at work in the engine,
everything has to be reguarly checked for tightness and there is a lot of lock wire involved! That said the 50 hour check up has shown no problems but that is to be expected as the engine is only operating at pretty light loads for most of the time.

Does any member know of any of these engines still in flying trim? I would be very interested to be in contact with other users even though my device never leaves the ground... hopefully.

[baldeagle]

I don't think that there are any 300HP Hissos flying (I think there are some running in vintage boats though), and only one geared 220, the one in the SPAD at the Memorial Flight in France. There are a number of direct drive 180s and 150s flying. I've flown several of them, and from the pilot's perspective at least they are very smooth engines.




-

[Catfish]

Hello Mr Anderson, and Taz,
thank you for this thread, really interesting. I made a translation i already quoted somewhere else in the aerodrome forum, but since it also fits in here ...

K. Jentsch compared the Spad with the german planes he knew, most of those with inline engines. After rereading the pages before and after i have the impression he flew a Pfalz D XII in Jasta 61 at that time. A bit strange because sometimes in the pages between he again speaks of an Albatros
Short before his test flight the Jasta 61 (?) received new Fokker D VII planes at july 30ieth. The Spad belonged to Jasta Boelcke, and Jentsch was invited to make a test flight:

"The SPAD is being pulled out of the tent, and made ready for start. A mechanic shortly explains the interior. The instruments are not mounted as clearly as in german army planes. The looping harness lets the pilot more freedom of movement than those being used by us. The engine, being a Hispano-Suiza, has to be actuated manually, seemingly the frankmen [or "frenchmen", kind of slang, but not as bad as "boche", "Franzmaenner" in german] do not seem to have heard of starters. After some misfiring i am able to start. The engines's revolutions, around 2400 per minute, are higher than those of our planes.
The SPAD lies wonderfully in the air, and responds well to the slightest control moves. Additionally the engine runs without jolting due to its favourable V-shape. The machine lies calmly in the air, there are no vibrations like in our planes, which are being triggered by the construction type of german in-line engines.
Material is no object for the enemy states. The whole world is open for them for provisioning of raw and working materials. With such a background top performance in the construction of planes can be achieved. The performance of the SPAD towers high above our machines. The loopings and barrel rolls finally validate my assumption. And now i suddenly realize why the first attack by a SPAD is so dangerous, they almost cannot miss while shooting with the calm behaviour and brilliant field of vision. Our fighter pilots at the controls of their SPADs, this would almost put an end to enemy aviation.
Against my expectations i manage to make a good landing. Because of the vertical tail skid i have to land on the wheels. The SPAD needs a long runway to come to full stop, but the aerodrome of Chambry holds no perils in that respect."

Some days later, at August 13th, 1918, Jentsch was transferred to the Jasta Boelcke.
So even if the Spad V8 had some bad vibrations or behaved shaky it seems it was still a smoother engine than Jentsch experienced from german inline "straight-six" engines - the last inliners he flew before the Spad were most probably the Albatros D III, and the Pfalz D XII, if not a Fokker D VII.

Mr Anderson, you wrote about the inline six-cyl. engines:
"The only really important Torsional vibration in these engines is the one that is usually not felt by the pilot but will destroy the engine over a period of time. The reason for the Lanchester Vibration Dampener"
Now i have sought for this and a picture but i did not quite get what it is - this must be a device to dampen the up-and-down movement at the front and back end ? I am sure every engine would need such a device -

Thanks and greetings,
Catfish

[m9a3r5i7o2n]

-------THE HISPANO-SUIZA 718 c.i. 8A PROBLEMS LONGERONS (#2)--------
The SPAD 7 when first entered into service in 1916 had some severe problems, see book, “French Aircraft of the First World War”, page 485 second paragraph one and two under SPAD 7. Some of which was the fault of the radiator cowling and some with the engine vibration causing the engine bearing longerons to break. The two steel plates were added to the longerons, one each side.
The exact words were. “The engine bearers were reinforced with steel plates, as it was found that there were frequent failures as a result of engine vibrations.”
I would imagine that the plates were affixed to the bottom of the longerons which would require 18 holes spaced at 75,73.73,78,78,73,73, 92 mm and 334mm from side to side. This should give us an idea of the power of the vibration. The bolts required were 3/8” (6.525mm) but no thread type/size/pitch given. These figures given on the Sunbeam-Arab which is supposedly the same as the Hispano-Suiza. This makes the bolt pattern 24.213” long or 615mm. A very long piece of steel. It would be interesting to know just how wide and thick it was. My guess is .250” thick and a width of 1.875”.
It did not state if the plate was just drilled or whether it was drilled and tapped and the bolts tightened into the plate being on the bottom. If it were on top it would just be drilled and the bolts being tightened into nuts on the bottom. Both drilling and tapping would be preferable to save the weight of the nuts required altho the plate was likely not very thick. But then again the 18 bolts multiplied by the number of effective threads might be very sufficient to do the job.
I have made a sketch of what I believe the plate may have appeared to be but actual plates may have differed in many small respects. We do not know just where the plate went especially if on top or the under side as it appears the bottom side of the longerons would be somewhat superior to me. But you never know how heavy the plate needed to be in their theories. Also we do not know if it was bolted directly into the plate or into nuts.
If the bolts were .375” by 24 threads per inch there would be 4 full threads in tension at each bolt. Four threads times 18 would be 72 threads in holding force at any time. This should have been adequate for any forces this engine was going to exert against the longeron. Later on I believe they reinforced the longeron itself!
M.L. Anderson

[m9a3r5i7o2n]

Mr Anderson, you wrote about the inline six-cyl. engines:
"The only really important Torsional vibration in these engines is the one that is usually not felt by the pilot but will destroy the engine over a period of time. The reason for the Lanchester Vibration Dampener"
Now I have sought for this and a picture but I did not quite get what it is - this must be a device to dampen the up-and-down movement at the front and back end ? I am sure every engine would need such a device -

Thanks and greetings,
Catfish


Catfish
Go here first;
Atomic Performance Products

and then if this does not answer your question type up the words, “Torsional Vibration Dampener” on the Internet and there are hundreds of places both showing and telling about them. It is a very simple rotary device. I only works in the rotary direction!

Yours, M.L. Anderson